Convert.ToInt64 方法

定义

将指定的值转换为 64 位有符号整数。

重载

ToInt64(Single)

将指定的单精度浮点数的值转换为等效的 64 位带符号整数。

ToInt64(String, Int32)

将指定基数的数字的字符串表示形式转换为等效的 64 位有符号整数。

ToInt64(String, IFormatProvider)

使用指定的区域性特定格式设置信息,将数字的指定字符串表示形式转换为等效的 64 位带符号整数。

ToInt64(Object, IFormatProvider)

使用指定的区域性特定格式信息,将指定对象的值转换为 64 位带符号整数。

ToInt64(UInt64)

将指定的 64 位无符号整数的值转换为等效的 64 位有符号整数。

ToInt64(UInt32)

将指定的 32 位无符号整数的值转换为等效的 64 位有符号整数。

ToInt64(UInt16)

将指定的 16 位无符号整数的值转换为等效的 64 位有符号整数。

ToInt64(String)

将数字的指定字符串表示形式转换为等效的 64 位带符号整数。

ToInt64(SByte)

将指定的 8 位带符号整数的值转换为等效的 64 位带符号整数。

ToInt64(Object)

将指定对象的值转换为 64 位带符号整数。

ToInt64(Int64)

返回指定的 64 位有符号整数;不执行实际的转换。

ToInt64(Byte)

将指定的 8 位无符号整数的值转换为等效的 64 位有符号整数。

ToInt64(Char)

将指定的 Unicode 字符的值转换为等效的 64 位有符号整数。

ToInt64(DateTime)

调用此方法始终引发 InvalidCastException

ToInt64(Boolean)

将指定的布尔值转换为等效的 64 位带符号整数。

ToInt64(Double)

将指定的双精度浮点数的值转换为等效的 64 位带符号整数。

ToInt64(Int16)

将指定的 16 位有符号整数的值转换为等效的 64 位有符号整数。

ToInt64(Int32)

将指定的 32 位有符号整数的值转换为等效的 64 位有符号整数。

ToInt64(Decimal)

将指定的十进制数的值转换为等效的 64 位带符号整数。

ToInt64(Single)

将指定的单精度浮点数的值转换为等效的 64 位带符号整数。

public:
 static long ToInt64(float value);
public static long ToInt64 (float value);
static member ToInt64 : single -> int64
Public Shared Function ToInt64 (value As Single) As Long

参数

value
Single

要转换的单精度浮点数。

返回

value,舍入为最接近的 64 位有符号整数。 如果 value 为两个整数中间的数字,则返回二者中的偶数;即 4.5 转换为 4,而 5.5 转换为 6。

例外

value 大于 Int64.MaxValue 或小于 Int64.MinValue

示例

以下示例尝试将值数组 Single 中的每个元素转换为长整数。

float[] values= { Single.MinValue, -1.38e10f, -1023.299f, -12.98f,
                  0f, 9.113e-16f, 103.919f, 17834.191f, Single.MaxValue };
long result;

foreach (float value in values)
{
   try {
      result = Convert.ToInt64(value);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        value.GetType().Name, value, result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("{0} is outside the range of the Int64 type.", value);
   }
}
// The example displays the following output:
//    -3.4028235E+38 is outside the range of the Int64 type.
//    Converted the Single value -1.38E+10 to the Int64 value -13799999488.
//    Converted the Single value -1023.299 to the Int64 value -1023.
//    Converted the Single value -12.98 to the Int64 value -13.
//    Converted the Single value 0 to the Int64 value 0.
//    Converted the Single value 9.113E-16 to the Int64 value 0.
//    Converted the Single value 103.919 to the Int64 value 104.
//    Converted the Single value 17834.191 to the Int64 value 17834.
//    3.4028235E+38 is outside the range of the Int64 type.
let values =
    [| Single.MinValue; -1.38e10f; -1023.299f; -12.98f
       0f; 9.113e-16f; 103.919f; 17834.191f; Single.MaxValue |]

for value in values do
    try
        let result = Convert.ToInt64 value
        printfn $"Converted the {value.GetType().Name} value {value} to the {result.GetType().Name} value {result}."
    with :? OverflowException ->
        printfn $"{value} is outside the range of the Int64 type."
// The example displays the following output:
//    -3.40282346638529E+38 is outside the range of the Int64 type.
//    -13799999488 is outside the range of the Int64 type.
//    Converted the Double value -1023.29901123047 to the Int64 value -1023.
//    Converted the Double value -12.9799995422363 to the Int64 value -13.
//    Converted the Double value 0 to the Int64 value 0.
//    Converted the Double value 9.11299983940444E-16 to the Int64 value 0.
//    Converted the Double value 103.918998718262 to the Int64 value 104.
//    Converted the Double value 17834.19140625 to the Int64 value 17834.
//    3.40282346638529E+38 is outside the range of the Int64 type.
Dim values() As Single = { Single.MinValue, -1.38e10, -1023.299, -12.98, _
                           0, 9.113e-16, 103.919, 17834.191, Single.MaxValue }
Dim result As Long

For Each value As Single In values
   Try
      result = Convert.ToInt64(value)
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.", _
                        value.GetType().Name, value, result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("{0} is outside the range of the Int64 type.", value)
   End Try
Next
' The example displays the following output:
'    -3.4028235E+38 is outside the range of the Int64 type.
'    Converted the Single value -1.38E+10 to the Int64 value -13799999488.
'    Converted the Single value -1023.299 to the Int64 value -1023.
'    Converted the Single value -12.98 to the Int64 value -13.
'    Converted the Single value 0 to the Int64 value 0.
'    Converted the Single value 9.113E-16 to the Int64 value 0.
'    Converted the Single value 103.919 to the Int64 value 104.
'    Converted the Single value 17834.191 to the Int64 value 17834.
'    3.4028235E+38 is outside the range of the Int64 type.

另请参阅

适用于

ToInt64(String, Int32)

将指定基数的数字的字符串表示形式转换为等效的 64 位有符号整数。

public:
 static long ToInt64(System::String ^ value, int fromBase);
public static long ToInt64 (string value, int fromBase);
public static long ToInt64 (string? value, int fromBase);
static member ToInt64 : string * int -> int64
Public Shared Function ToInt64 (value As String, fromBase As Integer) As Long

参数

value
String

包含要转换的数字的字符串。

fromBase
Int32

value 中数字的基数,它必须是 2、8、10 或 16。

返回

一个与 value 中数字等效的 64 位带符号整数,如果 valuenull,则为 0(零)。

例外

fromBase 不是 2、8、10 或 16。

value(表示基数不为 10 的符号数字)的前缀为负号。

value 包含一个字符,该字符不是由 fromBase 指定的基数中的有效数字。 如果 value 中的第一个字符无效,则该异常消息指示没有要转换的数字;否则,该消息指示 value 包含无效的尾随字符。

value(表示基数不为 10 的符号数字)的前缀为负号。

value 表示小于 Int64.MinValue 或大于 Int64.MaxValue 的数字

注解

如果 fromBase 为 16,则可以在参数指定的 value 数字前面添加“0x”或“0X”。

由于非基数 10 数值表示形式不支持负号,因此 该方法 ToInt64(String, Int32) 假定负数使用二的补补表示形式。 换句话说,方法始终将长整数的最高二进制位 (位 63) 解释为其符号位。 因此,可以编写代码,将数据类型范围 Int64 外的非基数 10 转换为 Int64 值,而不会引发方法异常。 以下示例将 转换为 MaxValue 其十六进制字符串表示形式,然后调用 ToInt64(String, Int32) 方法。 方法显示消息“0xFFFFFFFFFFFFFFFF转换为 -1”,而不是引发异常。

// Create a hexadecimal value out of range of the long type.
string value = ulong.MaxValue.ToString("X");
// Use Convert.ToInt64 to convert it back to a number.
try
{
   long number = Convert.ToInt64(value, 16);
   Console.WriteLine("0x{0} converts to {1}.", value, number);
}
catch (OverflowException)
{
   Console.WriteLine("Unable to convert '0x{0}' to a long integer.", value);
}
// Create a hexadecimal value out of range of the long type.
let value = UInt64.MaxValue.ToString "X"
// Use Convert.ToInt64 to convert it back to a number.
try
    let number = Convert.ToInt64(value, 16)
    printfn $"0x{value} converts to {number}."
with :? OverflowException ->
    printfn $"Unable to convert '0x{value}' to a long integer."
' Create a hexadecimal value out of range of the Long type.
Dim value As String = ULong.MaxValue.ToString("X")
' Call Convert.ToInt64 to convert it back to a number.
Try
   Dim number As Long = Convert.ToInt64(value, 16)
   Console.WriteLine("0x{0} converts to {1}.", value, number)
Catch e As OverflowException
   Console.WriteLine("Unable to convert '0x{0}' to a long integer.", value)
End Try

在执行二进制运算或数值转换时,开发人员始终有责任验证方法是否使用适当的数值表示形式来解释特定值。 如以下示例所示,在将值转换为其十六进制字符串表示形式时,首先确定值是表示无符号类型还是带符号类型,以确保该方法适当处理溢出。 如果原始值是无符号类型,但转换回整数会生成符号位处于打开状态的值,则引发异常。

// Create a negative hexadecimal value out of range of the Byte type.
ulong sourceNumber = ulong.MaxValue;
bool isSigned = Math.Sign(Convert.ToDouble(sourceNumber.GetType().GetField("MinValue").GetValue(null))) == -1;
string value = sourceNumber.ToString("X");
long targetNumber;
try
{
   targetNumber = Convert.ToInt64(value, 16);
   if (! isSigned && ((targetNumber & 0x80000000) != 0))
      throw new OverflowException();
   else
      Console.WriteLine("0x{0} converts to {1}.", value, targetNumber);
}
catch (OverflowException)
{
   Console.WriteLine("Unable to convert '0x{0}' to a long integer.", value);
}
// Displays the following to the console:
//    Unable to convert '0xFFFFFFFFFFFFFFFF' to a long integer.
// Create a negative hexadecimal value out of range of the Byte type.
let sourceNumber = UInt64.MaxValue
let isSigned = sign (Convert.ToDouble(sourceNumber.GetType().GetField("MinValue").GetValue null)) = -1
let value = sourceNumber.ToString "X"
try
    let targetNumber = Convert.ToInt64(value, 16)
    if not isSigned && targetNumber &&& 0x80000000L <> 0L then
        raise (OverflowException())
    else
        printfn $"0x{value} converts to {targetNumber}."
with :? OverflowException ->
    printfn $"Unable to convert '0x{value}' to a long integer."
// Displays the following to the console:
//    Unable to convert '0xFFFFFFFFFFFFFFFF' to a long integer.
' Create a negative hexadecimal value out of range of the Long type.
Dim sourceNumber As ULong = ULong.MaxValue
Dim isSigned As Boolean = Math.Sign(sourceNumber.MinValue) = -1
Dim value As String = sourceNumber.ToString("X")
Dim targetNumber As Long
Try
   targetNumber = Convert.ToInt64(value, 16)
   If Not isSigned And ((targetNumber And &H8000000000) <> 0) Then
      Throw New OverflowException()
   Else 
      Console.WriteLine("0x{0} converts to {1}.", value, targetNumber)
   End If    
Catch e As OverflowException
   Console.WriteLine("Unable to convert '0x{0}' to a long integer.", value)
End Try 
' Displays the following to the console:
'    Unable to convert '0xFFFFFFFFFFFFFFFF' to a long integer.

以下示例尝试将字符串数组中的每个元素解释为十六进制字符串,并将其转换为长整数。

using System;

public class Example
{
   public static void Main()
   {
      string[] hexStrings = { "8000000000000000", "0FFFFFFFFFFFFFFF",
                              "f0000000000001000", "00A30", "D", "-13", "GAD" };
      foreach (string hexString in hexStrings)
      {
         try {
            long number = Convert.ToInt64(hexString, 16);
            Console.WriteLine("Converted '{0}' to {1:N0}.", hexString, number);
         }
         catch (FormatException) {
            Console.WriteLine("'{0}' is not in the correct format for a hexadecimal number.",
                              hexString);
         }
         catch (OverflowException) {
            Console.WriteLine("'{0}' is outside the range of an Int64.", hexString);
         }
         catch (ArgumentException) {
            Console.WriteLine("'{0}' is invalid in base 16.", hexString);
         }
      }
   }
}
// The example displays the following output:
//       Converted '8000000000000000' to -9,223,372,036,854,775,808.
//       Converted '0FFFFFFFFFFFFFFF' to 1,152,921,504,606,846,975.
//       'f0000000000001000' is outside the range of an Int64.
//       Converted '00A30' to 2,608.
//       Converted 'D' to 13.
//       '-13' is invalid in base 16.
//       'GAD' is not in the correct format for a hexadecimal number.
open System

let hexStrings =
    [| "8000000000000000"; "0FFFFFFFFFFFFFFF"
       "f0000000000001000"; "00A30"; "D"; "-13"; "GAD" |]
for hexString in hexStrings do
    try
        let number = Convert.ToInt64(hexString, 16)
        printfn $"Converted '{hexString}' to {number:N0}."
    with
    | :? FormatException ->
        printfn $"'{hexString}' is not in the correct format for a hexadecimal number."
    | :? OverflowException ->
        printfn $"'{hexString}' is outside the range of an Int64."
    | :? ArgumentException ->
        printfn $"'{hexString}' is invalid in base 16."
// The example displays the following output:
//       Converted '8000000000000000' to -9,223,372,036,854,775,808.
//       Converted '0FFFFFFFFFFFFFFF' to 1,152,921,504,606,846,975.
//       'f0000000000001000' is outside the range of an Int64.
//       Converted '00A30' to 2,608.
//       Converted 'D' to 13.
//       '-13' is invalid in base 16.
//       'GAD' is not in the correct format for a hexadecimal number.
Module Example
   Public Sub Main()
      Dim hexStrings() As String = { "8000000000000000", "0FFFFFFFFFFFFFFF", _
                                     "f0000000000001000", "00A30", "D", "-13", "GAD" }
      For Each hexString As String In hexStrings
         Try
            Dim number As Long = Convert.ToInt64(hexString, 16)
            Console.WriteLine("Converted '{0}' to {1:N0}.", hexString, number)
         Catch e As FormatException
            Console.WriteLine("'{0}' is not in the correct format for a hexadecimal number.", _
                              hexString)
         Catch e As OverflowException
            Console.WriteLine("'{0}' is outside the range of an Int64.", hexString)
         Catch e As ArgumentException
            Console.WriteLine("'{0}' is invalid in base 16.", hexString)
         End Try
      Next                                            
   End Sub
End Module
' The example displays the following output:
'       Converted '8000000000000000' to -9,223,372,036,854,775,808.
'       Converted '0FFFFFFFFFFFFFFF' to 1,152,921,504,606,846,975.
'       'f0000000000001000' is outside the range of an Int64.
'       Converted '00A30' to 2,608.
'       Converted 'D' to 13.
'       '-13' is invalid in base 16.
'       'GAD' is not in the correct format for a hexadecimal number.

适用于

ToInt64(String, IFormatProvider)

使用指定的区域性特定格式设置信息,将数字的指定字符串表示形式转换为等效的 64 位带符号整数。

public:
 static long ToInt64(System::String ^ value, IFormatProvider ^ provider);
public static long ToInt64 (string value, IFormatProvider provider);
public static long ToInt64 (string? value, IFormatProvider? provider);
static member ToInt64 : string * IFormatProvider -> int64
Public Shared Function ToInt64 (value As String, provider As IFormatProvider) As Long

参数

value
String

包含要转换的数字的字符串。

provider
IFormatProvider

一个提供区域性特定的格式设置信息的对象。

返回

一个与 value 中数字等效的 64 位带符号整数,如果 valuenull,则为 0(零)。

例外

value 不由一个可选符号后跟一系列数字 (0-9) 组成。

示例

以下示例定义一个自定义 NumberFormatInfo 对象,该对象将字符串“pos”识别为正号,将字符串“neg”识别为负号。 然后,它会尝试使用此提供程序和 NumberFormatInfo 固定区域性的提供程序将数值字符串数组的每个元素转换为整数。

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      // Create a NumberFormatInfo object and set the properties that
      // affect conversions using Convert.ToInt64(String, IFormatProvider).
      NumberFormatInfo customProvider = new NumberFormatInfo();
      customProvider.NegativeSign = "neg ";
      customProvider.PositiveSign = "pos ";

      // Create an array of providers with the custom provider and the
      // NumberFormatInfo object for the invariant culture.
      NumberFormatInfo[] providers = { customProvider,
                                       NumberFormatInfo.InvariantInfo };

      // Define an array of strings to parse.
      string[] numericStrings = { "123456789", "+123456789", "pos 123456789",
                                  "-123456789", "neg 123456789", "123456789.",
                                  "123,456,789", "(123456789)",
                                  "9223372036854775808", "-9223372036854775809" };

      for (int ctr = 0; ctr < 2; ctr++)
      {
         IFormatProvider provider = providers[ctr];
         Console.WriteLine(ctr == 0 ? "Custom Provider:" : "Invariant Culture:");
         foreach (string numericString in numericStrings)
         {
            Console.Write("   {0,-22} -->  ", numericString);
            try {
               Console.WriteLine("{0,22}", Convert.ToInt32(numericString, provider));
            }
            catch (FormatException) {
               Console.WriteLine("{0,22}", "Unrecognized Format");
            }
            catch (OverflowException) {
               Console.WriteLine("{0,22}", "Overflow");
            }
         }
         Console.WriteLine();
      }
   }
}
// The example displays the following output:
//       Custom Provider:
//          123456789              -->               123456789
//          +123456789             -->     Unrecognized Format
//          pos 123456789          -->               123456789
//          -123456789             -->     Unrecognized Format
//          neg 123456789          -->              -123456789
//          123456789.             -->     Unrecognized Format
//          123,456,789            -->     Unrecognized Format
//          (123456789)            -->     Unrecognized Format
//          9223372036854775808    -->                Overflow
//          -9223372036854775809   -->     Unrecognized Format
//
//       Invariant Culture:
//          123456789              -->               123456789
//          +123456789             -->               123456789
//          pos 123456789          -->     Unrecognized Format
//          -123456789             -->              -123456789
//          neg 123456789          -->     Unrecognized Format
//          123456789.             -->     Unrecognized Format
//          123,456,789            -->     Unrecognized Format
//          (123456789)            -->     Unrecognized Format
//          9223372036854775808    -->                Overflow
//          -9223372036854775809   -->                Overflow
open System
open System.Globalization

// Create a NumberFormatInfo object and set the properties that
// affect conversions using Convert.ToInt64(String, IFormatProvider).
let customProvider = NumberFormatInfo()
customProvider.NegativeSign <- "neg "
customProvider.PositiveSign <- "pos "

// Create an array of providers with the custom provider and the
// NumberFormatInfo object for the invariant culture.
let providers =
    [| customProvider; NumberFormatInfo.InvariantInfo |]

// Define an array of strings to parse.
let numericStrings =
    [| "123456789"; "+123456789"; "pos 123456789"
       "-123456789"; "neg 123456789"; "123456789."
       "123,456,789"; "(123456789)"
       "9223372036854775808"; "-9223372036854775809" |]

for i = 0 to 2 do
    let provider = providers[i]
    printfn $"""{if i = 0 then "Custom Provider:" else "Invariant Culture:"}"""
    for numericString in numericStrings do
        printf $"   {numericString,-22} -->  "
        try
            printfn $"{Convert.ToInt32(numericString, provider),22}"
        with
        | :? FormatException ->
            printfn "%22s" "Unrecognized Format"
        | :? OverflowException ->
            printfn "%22s" "Overflow"
    printfn ""

// The example displays the following output:
//       Custom Provider:
//          123456789              -->               123456789
//          +123456789             -->     Unrecognized Format
//          pos 123456789          -->               123456789
//          -123456789             -->     Unrecognized Format
//          neg 123456789          -->              -123456789
//          123456789.             -->     Unrecognized Format
//          123,456,789            -->     Unrecognized Format
//          (123456789)            -->     Unrecognized Format
//          9223372036854775808    -->                Overflow
//          -9223372036854775809   -->     Unrecognized Format
//
//       Invariant Culture:
//          123456789              -->               123456789
//          +123456789             -->               123456789
//          pos 123456789          -->     Unrecognized Format
//          -123456789             -->              -123456789
//          neg 123456789          -->     Unrecognized Format
//          123456789.             -->     Unrecognized Format
//          123,456,789            -->     Unrecognized Format
//          (123456789)            -->     Unrecognized Format
//          9223372036854775808    -->                Overflow
//          -9223372036854775809   -->                Overflow
Imports System.Globalization

Public Module Example
   Public Sub Main()
      ' Create a NumberFormatInfo object and set the properties that
      ' affect conversions using Convert.ToInt64(String, IFormatProvider).
      Dim customProvider As New NumberFormatInfo()
      customProvider.NegativeSign = "neg "
      customProvider.PositiveSign = "pos "

      ' Create an array of providers with the custom provider and the
      ' NumberFormatInfo object for the invariant culture.
      Dim providers() As NumberFormatInfo = {customProvider, _
                                             NumberFormatInfo.InvariantInfo }
      
      ' Define an array of strings to parse.
      Dim numericStrings() As String = { "123456789", "+123456789", _
                                         "pos 123456789", "-123456789", _
                                         "neg 123456789", "123456789.", _
                                         "123,456,789", "(123456789)", _
                                         "9223372036854775808", "-9223372036854775809" }

      For ctr As Integer = 0 to 1
         Dim provider As IFormatProvider = providers(ctr)
         Console.WriteLine(IIf(ctr = 0, "Custom Provider:", "Invariant Culture:"))
         For Each numericString As String In numericStrings
            Console.Write("   {0,-22} -->  ", numericString)
            Try
               Console.WriteLine("{0,22}", Convert.ToInt32(numericString, provider))
            Catch e As FormatException
               Console.WriteLine("{0,22}", "Unrecognized Format")
            Catch e As OverflowException
               Console.WriteLine("{0,22}", "Overflow")
            End Try
         Next
         Console.WriteLine()
      Next
   End Sub 
End Module 
' The example displays the following output:
'       Custom Provider:
'          123456789              -->               123456789
'          +123456789             -->     Unrecognized Format
'          pos 123456789          -->               123456789
'          -123456789             -->     Unrecognized Format
'          neg 123456789          -->              -123456789
'          123456789.             -->     Unrecognized Format
'          123,456,789            -->     Unrecognized Format
'          (123456789)            -->     Unrecognized Format
'          9223372036854775808    -->                Overflow
'          -9223372036854775809   -->     Unrecognized Format
'       
'       Invariant Culture:
'          123456789              -->               123456789
'          +123456789             -->               123456789
'          pos 123456789          -->     Unrecognized Format
'          -123456789             -->              -123456789
'          neg 123456789          -->     Unrecognized Format
'          123456789.             -->     Unrecognized Format
'          123,456,789            -->     Unrecognized Format
'          (123456789)            -->     Unrecognized Format
'          9223372036854775808    -->                Overflow
'          -9223372036854775809   -->                Overflow

注解

返回值是在 上value调用 Int64.Parse 方法的结果。

provider 是获取 IFormatProviderNumberFormatInfo 对象的实例。 对象 NumberFormatInfo 提供有关 格式的 value区域性特定信息。 如果 providernullNumberFormatInfo 则使用当前区域性的 。

如果不想在转换失败时处理异常,可以改为调用 Int64.TryParse 方法。 它返回一个 Boolean 值,该值指示转换是成功还是失败。

适用于

ToInt64(Object, IFormatProvider)

使用指定的区域性特定格式信息,将指定对象的值转换为 64 位带符号整数。

public:
 static long ToInt64(System::Object ^ value, IFormatProvider ^ provider);
public static long ToInt64 (object value, IFormatProvider provider);
public static long ToInt64 (object? value, IFormatProvider? provider);
static member ToInt64 : obj * IFormatProvider -> int64
Public Shared Function ToInt64 (value As Object, provider As IFormatProvider) As Long

参数

value
Object

一个实现 IConvertible 接口的对象。

provider
IFormatProvider

一个提供区域性特定的格式设置信息的对象。

返回

一个与 value 等效的 64 位带符号整数,如果 valuenull,则为零。

例外

value 的格式不正确。

value 不实现 IConvertible 接口。

不支持该转换。

示例

以下示例定义实现 的 IConvertible 类和实现 的 IFormatProvider类。 实现 IConvertible 的 类的对象保存值数组 Double 。 每个类的 一个 对象将 ToInt64 传递给 方法。 此方法使用实现IFormatProvider的 对象来确定如何计算平均值,返回值数组Double的平均值。

using namespace System;
using namespace System::Collections;

// Define the types of averaging available in the class 
// implementing IConvertible.
public enum class AverageType : short
{
   None = 0,
   GeometricMean = 1,
   ArithmeticMean = 2,
   Median = 3
};


// Pass an instance of this class to methods that require an 
// IFormatProvider. The class instance determines the type of 
// average to calculate.
ref class AverageInfo: public IFormatProvider
{
protected:
   AverageType AvgType;

public:

   // Specify the type of averaging in the constructor.
   AverageInfo( AverageType avgType )
   {
      this->AvgType = avgType;
   }


   // This method returns a reference to the containing object 
   // if an object of AverageInfo type is requested. 
   virtual Object^ GetFormat( Type^ argType )
   {
      if ( argType == AverageInfo::typeid)
            return this;
      else
            return (Object^)0;
   }


   property AverageType TypeOfAverage 
   {

      // Use this property to set or get the type of averaging.
      AverageType get()
      {
         return this->AvgType;
      }

      void set( AverageType value )
      {
         this->AvgType = value;
      }

   }

};


// This class encapsulates an array of double values and implements 
// the IConvertible interface. Most of the IConvertible methods 
// return an average of the array elements in one of three types: 
// arithmetic mean, geometric mean, or median. 
ref class DataSet: public IConvertible
{
private:
   static Object^ null = nullptr;

protected:
   ArrayList^ data;
   AverageInfo^ defaultProvider;

   // This method unboxes a boxed double.
   double UnBoxDouble( Object^ obj )
   {
      return  *static_cast<double^>(obj);
   }


public:

   // Construct the object and add an initial list of values.
   // Create a default format provider.
   DataSet( ... array<Double>^values )
   {
      data = gcnew ArrayList( (Array^)values );
      defaultProvider = gcnew AverageInfo( AverageType::ArithmeticMean );
   }


   // Add additional values with this method.
   int Add( double value )
   {
      data->Add( value );
      return data->Count;
   }


   property double Item[ int ]
   {

      // Get, set, and add values with this indexer property.
      double get( int index )
      {
         if ( index >= 0 && index < data->Count )
                  return UnBoxDouble( data[ index ] );
         else
                  throw gcnew InvalidOperationException( "[DataSet.get] Index out of range." );
      }

      void set( int index, double value )
      {
         if ( index >= 0 && index < data->Count )
                  data[ index ] = value;
         else
         if ( index == data->Count )
                  data->Add( value );
         else
                  throw gcnew InvalidOperationException( "[DataSet.set] Index out of range." );
      }

   }

   property int Count 
   {

      // This property returns the number of elements in the object.
      int get()
      {
         return data->Count;
      }

   }

protected:

   // This method calculates the average of the object's elements.
   double Average( AverageType avgType )
   {
      double SumProd;
      if ( data->Count == 0 )
            return 0.0;

      switch ( avgType )
      {
         case AverageType::GeometricMean:
            SumProd = 1.0;
            for ( int Index = 0; Index < data->Count; Index++ )
               SumProd *= UnBoxDouble( data[ Index ] );
            
            // This calculation will not fail with negative 
            // elements.
            return Math::Sign( SumProd ) * Math::Pow( Math::Abs( SumProd ), 1.0 / data->Count );

         case AverageType::ArithmeticMean:
            SumProd = 0.0;
            for ( int Index = 0; Index < data->Count; Index++ )
               SumProd += UnBoxDouble( data[ Index ] );
            return SumProd / data->Count;

         case AverageType::Median:
            if ( data->Count % 2 == 0 )
                        return (UnBoxDouble( data[ data->Count / 2 ] ) + UnBoxDouble( data[ data->Count / 2 - 1 ] )) / 2.0;
            else
                        return UnBoxDouble( data[ data->Count / 2 ] );

         default:
            return 0.0;
      }
   }


   // Get the AverageInfo object from the caller's format provider,
   // or use the local default.
   AverageInfo^ GetAverageInfo( IFormatProvider^ provider )
   {
      AverageInfo^ avgInfo = nullptr;
      if ( provider != nullptr )
            avgInfo = static_cast<AverageInfo^>(provider->GetFormat( AverageInfo::typeid ));

      if ( avgInfo == nullptr )
            return defaultProvider;
      else
            return avgInfo;
   }


   // Calculate the average and limit the range.
   double CalcNLimitAverage( double min, double max, IFormatProvider^ provider )
   {
      
      // Get the format provider and calculate the average.
      AverageInfo^ avgInfo = GetAverageInfo( provider );
      double avg = Average( avgInfo->TypeOfAverage );
      
      // Limit the range, based on the minimum and maximum values 
      // for the type.
      return avg > max ? max : avg < min ? min : avg;
   }


public:

   // The following elements are required by IConvertible.
   // None of these conversion functions throw exceptions. When
   // the data is out of range for the type, the appropriate
   // MinValue or MaxValue is used.
   virtual TypeCode GetTypeCode()
   {
      return TypeCode::Object;
   }

   virtual bool ToBoolean( IFormatProvider^ provider )
   {
      
      // ToBoolean is false if the dataset is empty.
      if ( data->Count <= 0 )
            return false;
      // For median averaging, ToBoolean is true if any 
      // non-discarded elements are nonzero.
      else
      
      // For median averaging, ToBoolean is true if any 
      // non-discarded elements are nonzero.
      if ( AverageType::Median == GetAverageInfo( provider )->TypeOfAverage )
      {
         if ( data->Count % 2 == 0 )
                  return (UnBoxDouble( data[ data->Count / 2 ] ) != 0.0 || UnBoxDouble( data[ data->Count / 2 - 1 ] ) != 0.0);
         else
                  return UnBoxDouble( data[ data->Count / 2 ] ) != 0.0;
      }
      // For arithmetic or geometric mean averaging, ToBoolean is 
      // true if any element of the dataset is nonzero.  
      else
      {
         for ( int Index = 0; Index < data->Count; Index++ )
            if ( UnBoxDouble( data[ Index ] ) != 0.0 )
                        return true;
         return false;
      }
   }

   virtual Byte ToByte( IFormatProvider^ provider )
   {
      return Convert::ToByte( CalcNLimitAverage( Byte::MinValue, Byte::MaxValue, provider ) );
   }

   virtual Char ToChar( IFormatProvider^ provider )
   {
      return Convert::ToChar( Convert::ToUInt16( CalcNLimitAverage( Char::MinValue, Char::MaxValue, provider ) ) );
   }


   // Convert to DateTime by adding the calculated average as 
   // seconds to the current date and time. A valid DateTime is 
   // always returned.
   virtual DateTime ToDateTime( IFormatProvider^ provider )
   {
      double seconds = Average( GetAverageInfo( provider )->TypeOfAverage );
      try
      {
         return DateTime::Now.AddSeconds( seconds );
      }
      catch ( ArgumentOutOfRangeException^ ) 
      {
         return seconds < 0.0 ? DateTime::MinValue : DateTime::MaxValue;
      }

   }

   virtual Decimal ToDecimal( IFormatProvider^ provider )
   {
      
      // The Double conversion rounds Decimal.MinValue and 
      // Decimal.MaxValue to invalid Decimal values, so the 
      // following limits must be used.
      return Convert::ToDecimal( CalcNLimitAverage(  -79228162514264330000000000000.0, 79228162514264330000000000000.0, provider ) );
   }

   virtual double ToDouble( IFormatProvider^ provider )
   {
      return Average( GetAverageInfo( provider )->TypeOfAverage );
   }

   virtual short ToInt16( IFormatProvider^ provider )
   {
      return Convert::ToInt16( CalcNLimitAverage( Int16::MinValue, Int16::MaxValue, provider ) );
   }

   virtual int ToInt32( IFormatProvider^ provider )
   {
      return Convert::ToInt32( CalcNLimitAverage( Int32::MinValue, Int32::MaxValue, provider ) );
   }

   virtual __int64 ToInt64( IFormatProvider^ provider )
   {
      
      // The Double conversion rounds Int64.MinValue and 
      // Int64.MaxValue to invalid Int64 values, so the following 
      // limits must be used.
      return Convert::ToInt64( CalcNLimitAverage(  -9223372036854775000, 9223372036854775000, provider ) );
   }

   virtual signed char ToSByte( IFormatProvider^ provider )
   {
      return Convert::ToSByte( CalcNLimitAverage( SByte::MinValue, SByte::MaxValue, provider ) );
   }

   virtual float ToSingle( IFormatProvider^ provider )
   {
      return Convert::ToSingle( CalcNLimitAverage( Single::MinValue, Single::MaxValue, provider ) );
   }

   virtual UInt16 ToUInt16( IFormatProvider^ provider )
   {
      return Convert::ToUInt16( CalcNLimitAverage( UInt16::MinValue, UInt16::MaxValue, provider ) );
   }

   virtual UInt32 ToUInt32( IFormatProvider^ provider )
   {
      return Convert::ToUInt32( CalcNLimitAverage( UInt32::MinValue, UInt32::MaxValue, provider ) );
   }

   virtual UInt64 ToUInt64( IFormatProvider^ provider )
   {
      
      // The Double conversion rounds UInt64.MaxValue to an invalid
      // UInt64 value, so the following limit must be used.
      return Convert::ToUInt64( CalcNLimitAverage( 0, 18446744073709550000.0, provider ) );
   }

   virtual Object^ ToType( Type^ conversionType, IFormatProvider^ provider )
   {
      return Convert::ChangeType( Average( GetAverageInfo( provider )->TypeOfAverage ), conversionType );
   }

   virtual String^ ToString( IFormatProvider^ provider )
   {
      AverageType avgType = GetAverageInfo( provider )->TypeOfAverage;
      return String::Format( "( {0}: {1:G10} )", avgType, Average( avgType ) );
   }

};


// Display a DataSet with three different format providers.
void DisplayDataSet( DataSet^ ds )
{
   IFormatProvider^ null = nullptr;
   String^ fmt = "{0,-12}{1,20}{2,20}{3,20}";
   AverageInfo^ median = gcnew AverageInfo( AverageType::Median );
   AverageInfo^ geMean = gcnew AverageInfo( AverageType::GeometricMean );
   
   // Display the dataset elements.
   if ( ds->Count > 0 )
   {
      Console::Write( "\nDataSet: [{0}", ds->Item[ 0 ] );
      for ( int iX = 1; iX < ds->Count; iX++ )
         Console::Write( ", {0}", ds->Item[ iX ] );
      Console::WriteLine( "]\n" );
   }

   Console::WriteLine( fmt, "Convert::", "Default", "Geometric Mean", "Median" );
   Console::WriteLine( fmt, "---------", "-------", "--------------", "------" );
   Console::WriteLine( fmt, "ToBoolean", Convert::ToBoolean( ds, null ), Convert::ToBoolean( ds, geMean ), Convert::ToBoolean( ds, median ) );
   Console::WriteLine( fmt, "ToByte", Convert::ToByte( ds, null ), Convert::ToByte( ds, geMean ), Convert::ToByte( ds, median ) );
   Console::WriteLine( fmt, "ToChar", Convert::ToChar( ds, null ), Convert::ToChar( ds, geMean ), Convert::ToChar( ds, median ) );
   Console::WriteLine( "{0,-12}{1,20:yyyy-MM-dd HH:mm:ss}"
   "{2,20:yyyy-MM-dd HH:mm:ss}{3,20:yyyy-MM-dd HH:mm:ss}", "ToDateTime", Convert::ToDateTime( ds, null ), Convert::ToDateTime( ds, geMean ), Convert::ToDateTime( ds, median ) );
   Console::WriteLine( fmt, "ToDecimal", Convert::ToDecimal( ds, null ), Convert::ToDecimal( ds, geMean ), Convert::ToDecimal( ds, median ) );
   Console::WriteLine( fmt, "ToDouble", Convert::ToDouble( ds, null ), Convert::ToDouble( ds, geMean ), Convert::ToDouble( ds, median ) );
   Console::WriteLine( fmt, "ToInt16", Convert::ToInt16( ds, null ), Convert::ToInt16( ds, geMean ), Convert::ToInt16( ds, median ) );
   Console::WriteLine( fmt, "ToInt32", Convert::ToInt32( ds, null ), Convert::ToInt32( ds, geMean ), Convert::ToInt32( ds, median ) );
   Console::WriteLine( fmt, "ToInt64", Convert::ToInt64( ds, null ), Convert::ToInt64( ds, geMean ), Convert::ToInt64( ds, median ) );
   Console::WriteLine( fmt, "ToSByte", Convert::ToSByte( ds, null ), Convert::ToSByte( ds, geMean ), Convert::ToSByte( ds, median ) );
   Console::WriteLine( fmt, "ToSingle", Convert::ToSingle( ds, null ), Convert::ToSingle( ds, geMean ), Convert::ToSingle( ds, median ) );
   Console::WriteLine( fmt, "ToUInt16", Convert::ToUInt16( ds, null ), Convert::ToUInt16( ds, geMean ), Convert::ToUInt16( ds, median ) );
   Console::WriteLine( fmt, "ToUInt32", Convert::ToUInt32( ds, null ), Convert::ToUInt32( ds, geMean ), Convert::ToUInt32( ds, median ) );
   Console::WriteLine( fmt, "ToUInt64", Convert::ToUInt64( ds, null ), Convert::ToUInt64( ds, geMean ), Convert::ToUInt64( ds, median ) );
}

int main()
{
   Console::WriteLine( "This example of the "
   "Convert::To<Type>( Object*, IFormatProvider* ) methods "
   "\ngenerates the following output. The example "
   "displays the values \nreturned by the methods, "
   "using several IFormatProvider objects.\n" );
   
   // To call a [ParamArray] method in C++, you cannot just
   // list the parameters, you need to build an array.
   array<Double>^dataElem = gcnew array<Double>(6);
   dataElem[ 0 ] = 10.5;
   dataElem[ 1 ] = 22.2;
   dataElem[ 2 ] = 45.9;
   dataElem[ 3 ] = 88.7;
   dataElem[ 4 ] = 156.05;
   dataElem[ 5 ] = 297.6;
   DataSet^ ds1 = gcnew DataSet( dataElem );
   DisplayDataSet( ds1 );
   dataElem = gcnew array<Double>(5);
   dataElem[ 0 ] = 359999.95;
   dataElem[ 1 ] = 425000;
   dataElem[ 2 ] = 499999.5;
   dataElem[ 3 ] = 775000;
   dataElem[ 4 ] = 1695000;
   DataSet^ ds2 = gcnew DataSet( dataElem );
   DisplayDataSet( ds2 );
}

/*
This example of the Convert::To<Type>( Object*, IFormatProvider* ) methods
generates the following output. The example displays the values
returned by the methods, using several IFormatProvider objects.

DataSet: [10.5, 22.2, 45.9, 88.7, 156.05, 297.6]

Convert::                Default      Geometric Mean              Median
---------                -------      --------------              ------
ToBoolean                   True                True                True
ToByte                       103                  59                  67
ToChar                         g                   ;                   C
ToDateTime   2003-05-13 15:30:23 2003-05-13 15:29:39 2003-05-13 15:29:47
ToDecimal       103.491666666667    59.4332135445164                67.3
ToDouble        103.491666666667    59.4332135445164                67.3
ToInt16                      103                  59                  67
ToInt32                      103                  59                  67
ToInt64                      103                  59                  67
ToSByte                      103                  59                  67
ToSingle                103.4917            59.43321                67.3
ToUInt16                     103                  59                  67
ToUInt32                     103                  59                  67
ToUInt64                     103                  59                  67

DataSet: [359999.95, 425000, 499999.5, 775000, 1695000]

Convert::                Default      Geometric Mean              Median
---------                -------      --------------              ------
ToBoolean                   True                True                True
ToByte                       255                 255                 255
ToChar                         ?                   ?                   ?
ToDateTime   2003-05-22 08:05:19 2003-05-20 22:54:57 2003-05-19 10:21:59
ToDecimal              750999.89    631577.237188435            499999.5
ToDouble               750999.89    631577.237188435            499999.5
ToInt16                    32767               32767               32767
ToInt32                   751000              631577              500000
ToInt64                   751000              631577              500000
ToSByte                      127                 127                 127
ToSingle                750999.9            631577.3            499999.5
ToUInt16                   65535               65535               65535
ToUInt32                  751000              631577              500000
ToUInt64                  751000              631577              500000
*/
using System;
using System.Collections;

// Define the types of averaging available in the class
// implementing IConvertible.
public enum AverageType : short
{
    None = 0,
    GeometricMean = 1,
    ArithmeticMean = 2,
    Median = 3
};

// Pass an instance of this class to methods that require an
// IFormatProvider. The class instance determines the type of
// average to calculate.
public class AverageInfo : IFormatProvider
{
    protected AverageType AvgType;

    // Specify the type of averaging in the constructor.
    public AverageInfo( AverageType avgType )
    {
        this.AvgType = avgType;
    }

    // This method returns a reference to the containing object
    // if an object of AverageInfo type is requested.
    public object GetFormat( Type argType )
    {
        if ( argType == typeof( AverageInfo ) )
            return this;
        else
            return null;
    }

    // Use this property to set or get the type of averaging.
    public AverageType TypeOfAverage
    {
        get { return this.AvgType; }
        set { this.AvgType = value; }
    }
}

// This class encapsulates an array of double values and implements
// the IConvertible interface. Most of the IConvertible methods
// return an average of the array elements in one of three types:
// arithmetic mean, geometric mean, or median.
public class DataSet : IConvertible
{
    protected ArrayList     data;
    protected AverageInfo   defaultProvider;

    // Construct the object and add an initial list of values.
    // Create a default format provider.
    public DataSet( params double[ ] values )
    {
        data = new ArrayList( values );
        defaultProvider =
            new AverageInfo( AverageType.ArithmeticMean );
    }

    // Add additional values with this method.
    public int Add( double value )
    {
        data.Add( value );
        return data.Count;
    }

    // Get, set, and add values with this indexer property.
    public double this[ int index ]
    {
        get
        {
            if( index >= 0 && index < data.Count )
                return (double)data[ index ];
            else
                throw new InvalidOperationException(
                    "[DataSet.get] Index out of range." );
        }
        set
        {
            if( index >= 0 && index < data.Count )
                data[ index ] = value;

            else if( index == data.Count )
                data.Add( value );
            else
                throw new InvalidOperationException(
                    "[DataSet.set] Index out of range." );
        }
    }

    // This property returns the number of elements in the object.
    public int Count
    {
        get { return data.Count; }
    }

    // This method calculates the average of the object's elements.
    protected double Average( AverageType avgType )
    {
        double  SumProd;

        if( data.Count == 0 )
            return 0.0;

        switch( avgType )
        {
            case AverageType.GeometricMean:

                SumProd = 1.0;
                for( int Index = 0; Index < data.Count; Index++ )
                    SumProd *= (double)data[ Index ];

                // This calculation will not fail with negative
                // elements.
                return Math.Sign( SumProd ) * Math.Pow(
                    Math.Abs( SumProd ), 1.0 / data.Count );

            case AverageType.ArithmeticMean:

                SumProd = 0.0;
                for( int Index = 0; Index < data.Count; Index++ )
                    SumProd += (double)data[ Index ];

                return SumProd / data.Count;

            case AverageType.Median:

                if( data.Count % 2 == 0 )
                    return ( (double)data[ data.Count / 2 ] +
                        (double)data[ data.Count / 2 - 1 ] ) / 2.0;
                else
                    return (double)data[ data.Count / 2 ];

            default:
                return 0.0;
        }
    }

    // Get the AverageInfo object from the caller's format provider,
    // or use the local default.
    protected AverageInfo GetAverageInfo( IFormatProvider provider )
    {
        AverageInfo avgInfo = null;

        if( provider != null )
            avgInfo = (AverageInfo)provider.GetFormat(
                typeof( AverageInfo ) );

        if ( avgInfo == null )
            return defaultProvider;
        else
            return avgInfo;
    }

    // Calculate the average and limit the range.
    protected double CalcNLimitAverage( double min, double max,
        IFormatProvider provider )
    {
        // Get the format provider and calculate the average.
        AverageInfo avgInfo = GetAverageInfo( provider );
        double avg = Average( avgInfo.TypeOfAverage );

        // Limit the range, based on the minimum and maximum values
        // for the type.
        return avg > max ? max : avg < min ? min : avg;
    }

    // The following elements are required by IConvertible.

    // None of these conversion functions throw exceptions. When
    // the data is out of range for the type, the appropriate
    // MinValue or MaxValue is used.
    public TypeCode GetTypeCode( )
    {
        return TypeCode.Object;
    }

    public bool ToBoolean( IFormatProvider provider )
    {
        // ToBoolean is false if the dataset is empty.
        if( data.Count <= 0 )
        {
            return false;
        }

        // For median averaging, ToBoolean is true if any
        // non-discarded elements are nonzero.
        else if( AverageType.Median ==
            GetAverageInfo( provider ).TypeOfAverage )
        {
            if (data.Count % 2 == 0 )
                return ( (double)data[ data.Count / 2 ] != 0.0 ||
                    (double)data[ data.Count / 2 - 1 ] != 0.0 );
            else
                return (double)data[ data.Count / 2 ] != 0.0;
        }

        // For arithmetic or geometric mean averaging, ToBoolean is
        // true if any element of the dataset is nonzero.
        else
        {
            for( int Index = 0; Index < data.Count; Index++ )
                if( (double)data[ Index ] != 0.0 )
                    return true;
            return false;
        }
    }

    public byte ToByte( IFormatProvider provider )
    {
        return Convert.ToByte( CalcNLimitAverage(
            Byte.MinValue, Byte.MaxValue, provider ) );
    }

    public char ToChar( IFormatProvider provider )
    {
        return Convert.ToChar( Convert.ToUInt16( CalcNLimitAverage(
            Char.MinValue, Char.MaxValue, provider ) ) );
    }

    // Convert to DateTime by adding the calculated average as
    // seconds to the current date and time. A valid DateTime is
    // always returned.
    public DateTime ToDateTime( IFormatProvider provider )
    {
        double seconds =
            Average( GetAverageInfo( provider ).TypeOfAverage );
        try
        {
            return DateTime.Now.AddSeconds( seconds );
        }
        catch( ArgumentOutOfRangeException )
        {
            return seconds < 0.0 ? DateTime.MinValue : DateTime.MaxValue;
        }
    }

    public decimal ToDecimal( IFormatProvider provider )
    {
        // The Double conversion rounds Decimal.MinValue and
        // Decimal.MaxValue to invalid Decimal values, so the
        // following limits must be used.
        return Convert.ToDecimal( CalcNLimitAverage(
            -79228162514264330000000000000.0,
            79228162514264330000000000000.0, provider ) );
    }

    public double ToDouble( IFormatProvider provider )
    {
        return Average( GetAverageInfo(provider).TypeOfAverage );
    }

    public short ToInt16( IFormatProvider provider )
    {
        return Convert.ToInt16( CalcNLimitAverage(
            Int16.MinValue, Int16.MaxValue, provider ) );
    }

    public int ToInt32( IFormatProvider provider )
    {
        return Convert.ToInt32( CalcNLimitAverage(
            Int32.MinValue, Int32.MaxValue, provider ) );
    }

    public long ToInt64( IFormatProvider provider )
    {
        // The Double conversion rounds Int64.MinValue and
        // Int64.MaxValue to invalid Int64 values, so the following
        // limits must be used.
        return Convert.ToInt64( CalcNLimitAverage(
            -9223372036854775000, 9223372036854775000, provider ) );
    }

    public SByte ToSByte( IFormatProvider provider )
    {
        return Convert.ToSByte( CalcNLimitAverage(
            SByte.MinValue, SByte.MaxValue, provider ) );
    }

    public float ToSingle( IFormatProvider provider )
    {
        return Convert.ToSingle( CalcNLimitAverage(
            Single.MinValue, Single.MaxValue, provider ) );
    }

    public UInt16 ToUInt16( IFormatProvider provider )
    {
        return Convert.ToUInt16( CalcNLimitAverage(
            UInt16.MinValue, UInt16.MaxValue, provider ) );
    }

    public UInt32 ToUInt32( IFormatProvider provider )
    {
        return Convert.ToUInt32( CalcNLimitAverage(
            UInt32.MinValue, UInt32.MaxValue, provider ) );
    }

    public UInt64 ToUInt64( IFormatProvider provider )
    {
        // The Double conversion rounds UInt64.MaxValue to an invalid
        // UInt64 value, so the following limit must be used.
        return Convert.ToUInt64( CalcNLimitAverage(
            0, 18446744073709550000.0, provider ) );
    }

    public object ToType( Type conversionType,
        IFormatProvider provider )
    {
        return Convert.ChangeType( Average(
            GetAverageInfo( provider ).TypeOfAverage ),
            conversionType );
    }

    public string ToString( IFormatProvider provider )
    {
        AverageType avgType = GetAverageInfo( provider ).TypeOfAverage;
        return String.Format( "( {0}: {1:G10} )", avgType,
            Average( avgType ) );
    }
}

class IConvertibleProviderDemo
{
    // Display a DataSet with three different format providers.
    public static void DisplayDataSet( DataSet ds )
    {
        string      fmt    = "{0,-12}{1,20}{2,20}{3,20}";
        AverageInfo median = new AverageInfo( AverageType.Median );
        AverageInfo geMean =
            new AverageInfo( AverageType.GeometricMean );

         // Display the dataset elements.
        if( ds.Count > 0 )
        {
            Console.Write( "\nDataSet: [{0}", ds[ 0 ] );
            for( int iX = 1; iX < ds.Count; iX++ )
                Console.Write( ", {0}", ds[ iX ] );
            Console.WriteLine( "]\n" );
        }

        Console.WriteLine( fmt, "Convert.", "Default",
            "Geometric Mean", "Median");
        Console.WriteLine( fmt, "--------", "-------",
            "--------------", "------");
        Console.WriteLine( fmt, "ToBoolean",
            Convert.ToBoolean( ds, null ),
            Convert.ToBoolean( ds, geMean ),
            Convert.ToBoolean( ds, median ) );
        Console.WriteLine( fmt, "ToByte",
            Convert.ToByte( ds, null ),
            Convert.ToByte( ds, geMean ),
            Convert.ToByte( ds, median ) );
        Console.WriteLine( fmt, "ToChar",
            Convert.ToChar( ds, null ),
            Convert.ToChar( ds, geMean ),
            Convert.ToChar( ds, median ) );
        Console.WriteLine( "{0,-12}{1,20:yyyy-MM-dd HH:mm:ss}" +
            "{2,20:yyyy-MM-dd HH:mm:ss}{3,20:yyyy-MM-dd HH:mm:ss}",
            "ToDateTime", Convert.ToDateTime( ds, null ),
            Convert.ToDateTime( ds, geMean ),
            Convert.ToDateTime( ds, median ) );
        Console.WriteLine( fmt, "ToDecimal",
            Convert.ToDecimal( ds, null ),
            Convert.ToDecimal( ds, geMean ),
            Convert.ToDecimal( ds, median ) );
        Console.WriteLine( fmt, "ToDouble",
            Convert.ToDouble( ds, null ),
            Convert.ToDouble( ds, geMean ),
            Convert.ToDouble( ds, median ) );
        Console.WriteLine( fmt, "ToInt16",
            Convert.ToInt16( ds, null ),
            Convert.ToInt16( ds, geMean ),
            Convert.ToInt16( ds, median ) );
        Console.WriteLine( fmt, "ToInt32",
            Convert.ToInt32( ds, null ),
            Convert.ToInt32( ds, geMean ),
            Convert.ToInt32( ds, median ) );
        Console.WriteLine( fmt, "ToInt64",
            Convert.ToInt64( ds, null ),
            Convert.ToInt64( ds, geMean ),
            Convert.ToInt64( ds, median ) );
        Console.WriteLine( fmt, "ToSByte",
            Convert.ToSByte( ds, null ),
            Convert.ToSByte( ds, geMean ),
            Convert.ToSByte( ds, median ) );
        Console.WriteLine( fmt, "ToSingle",
            Convert.ToSingle( ds, null ),
            Convert.ToSingle( ds, geMean ),
            Convert.ToSingle( ds, median ) );
        Console.WriteLine( fmt, "ToUInt16",
            Convert.ToUInt16( ds, null ),
            Convert.ToUInt16( ds, geMean ),
            Convert.ToUInt16( ds, median ) );
        Console.WriteLine( fmt, "ToUInt32",
            Convert.ToUInt32( ds, null ),
            Convert.ToUInt32( ds, geMean ),
            Convert.ToUInt32( ds, median ) );
        Console.WriteLine( fmt, "ToUInt64",
            Convert.ToUInt64( ds, null ),
            Convert.ToUInt64( ds, geMean ),
            Convert.ToUInt64( ds, median ) );
    }

    public static void Main( )
    {
        Console.WriteLine( "This example of " +
            "the Convert.To<Type>( object, IFormatProvider ) methods " +
            "\ngenerates the following output. The example " +
            "displays the values \nreturned by the methods, " +
            "using several IFormatProvider objects.\n" );

        DataSet ds1 = new DataSet(
            10.5, 22.2, 45.9, 88.7, 156.05, 297.6 );
        DisplayDataSet( ds1 );

        DataSet ds2 = new DataSet(
            359999.95, 425000, 499999.5, 775000, 1695000 );
        DisplayDataSet( ds2 );
    }
}

/*
This example of the Convert.To<Type>( object, IFormatProvider ) methods
generates the following output. The example displays the values
returned by the methods, using several IFormatProvider objects.

DataSet: [10.5, 22.2, 45.9, 88.7, 156.05, 297.6]

Convert.                 Default      Geometric Mean              Median
--------                 -------      --------------              ------
ToBoolean                   True                True                True
ToByte                       103                  59                  67
ToChar                         g                   ;                   C
ToDateTime   2003-05-13 15:04:12 2003-05-13 15:03:28 2003-05-13 15:03:35
ToDecimal       103.491666666667    59.4332135445164                67.3
ToDouble        103.491666666667    59.4332135445164                67.3
ToInt16                      103                  59                  67
ToInt32                      103                  59                  67
ToInt64                      103                  59                  67
ToSByte                      103                  59                  67
ToSingle                103.4917            59.43321                67.3
ToUInt16                     103                  59                  67
ToUInt32                     103                  59                  67
ToUInt64                     103                  59                  67

DataSet: [359999.95, 425000, 499999.5, 775000, 1695000]

Convert.                 Default      Geometric Mean              Median
--------                 -------      --------------              ------
ToBoolean                   True                True                True
ToByte                       255                 255                 255
ToChar                         ?                   ?                   ?
ToDateTime   2003-05-22 07:39:08 2003-05-20 22:28:45 2003-05-19 09:55:48
ToDecimal              750999.89    631577.237188435            499999.5
ToDouble               750999.89    631577.237188435            499999.5
ToInt16                    32767               32767               32767
ToInt32                   751000              631577              500000
ToInt64                   751000              631577              500000
ToSByte                      127                 127                 127
ToSingle                750999.9            631577.3            499999.5
ToUInt16                   65535               65535               65535
ToUInt32                  751000              631577              500000
ToUInt64                  751000              631577              500000
*/
open System
open System.Collections

// Define the types of averaging available in the class
// implementing IConvertible.
type AverageType =
    | None = 0s
    | GeometricMean = 1s
    | ArithmeticMean = 2s
    | Median = 3s

// Pass an instance of this class to methods that require an
// IFormatProvider. The class instance determines the type of
// average to calculate.
[<AllowNullLiteral>]
type AverageInfo(avgType: AverageType) =
    // Use this property to set or get the type of averaging.
    member val TypeOfAverage = avgType with get, set 
    
    interface IFormatProvider with
        // This method returns a reference to the containing object
        // if an object of AverageInfo type is requested.
        member this.GetFormat(argType: Type) =
            if argType = typeof<AverageInfo> then
                this
            else
                null

// This class encapsulates an array of double values and implements
// the IConvertible interface. Most of the IConvertible methods
// an average of the array elements in one of three types:
// arithmetic mean, geometric mean, or median.
type DataSet([<ParamArray>] values: double[]) =
    let data = ResizeArray values
    let defaultProvider =
        AverageInfo AverageType.ArithmeticMean

    // Add additional values with this method.
    member _.Add(value: double) =
        data.Add value
        data.Count

    // Get, set, and add values with this indexer property.
    member _.Item
        with get (index) =
            if index >= 0 && index < data.Count then
                data[index]
            else
                raise (InvalidOperationException "[DataSet.get] Index out of range.")
        and set index value =
            if index >= 0 && index < data.Count then
                data[index] <- value
            elif index = data.Count then
                data.Add value
            else
                raise (InvalidOperationException "[DataSet.set] Index out of range.")

    // This property returns the number of elements in the object.
    member _.Count =
        data.Count

    // This method calculates the average of the object's elements.
    member _.Average(avgType: AverageType) =
        if data.Count = 0 then
            0.0
        else
            match avgType with
            | AverageType.GeometricMean ->
                let sumProd =
                    Seq.reduce ( * ) data
                
                // This calculation will not fail with negative
                // elements.
                (sign sumProd |> float) * Math.Pow(abs sumProd, 1.0 / (float data.Count))

            | AverageType.ArithmeticMean ->
                Seq.average data

            | AverageType.Median ->
                if data.Count % 2 = 0 then
                    (data[data.Count / 2] + data[data.Count / 2 - 1]) / 2.0
                else
                    data[ data.Count / 2]
            | _ ->
                0.0

    // Get the AverageInfo object from the caller's format provider,
    // or use the local default.
    member _.GetAverageInfo(provider: IFormatProvider) =
        let avgInfo =
            if provider <> null then
                provider.GetFormat typeof<AverageInfo> :?> AverageInfo
            else 
                null

        if avgInfo = null then
            defaultProvider
        else
            avgInfo

    // Calculate the average and limit the range.
    member this.CalcNLimitAverage(min: double, max: double, provider: IFormatProvider) =
        // Get the format provider and calculate the average.
        let avgInfo = this.GetAverageInfo provider
        let avg = this.Average avgInfo.TypeOfAverage

        // Limit the range, based on the minimum and maximum values
        // for the type.
        if avg > max then max elif avg < min then min else avg

    // The following elements are required by IConvertible.
    interface IConvertible with
        // None of these conversion functions throw exceptions. When
        // the data is out of range for the type, the appropriate
        // MinValue or MaxValue is used.
        member _.GetTypeCode() =
            TypeCode.Object

        member this.ToBoolean(provider: IFormatProvider) =
            // ToBoolean is false if the dataset is empty.
            if data.Count <= 0 then
                false

            // For median averaging, ToBoolean is true if any
            // non-discarded elements are nonzero.
            elif AverageType.Median = this.GetAverageInfo(provider).TypeOfAverage then
                if data.Count % 2 = 0 then
                    (data[data.Count / 2] <> 0.0 || data[data.Count / 2 - 1] <> 0.0)
                else
                    data[data.Count / 2] <> 0.0

            // For arithmetic or geometric mean averaging, ToBoolean is
            // true if any element of the dataset is nonzero.
            else
                Seq.exists (fun x -> x <> 0.0) data

        member this.ToByte(provider: IFormatProvider) =
            Convert.ToByte(this.CalcNLimitAverage(float Byte.MinValue, float Byte.MaxValue, provider) )

        member this.ToChar(provider: IFormatProvider) =
            Convert.ToChar(Convert.ToUInt16(this.CalcNLimitAverage(float Char.MinValue, float Char.MaxValue, provider) ) )

        // Convert to DateTime by adding the calculated average as
        // seconds to the current date and time. A valid DateTime is
        // always returned.
        member this.ToDateTime(provider: IFormatProvider) =
            let seconds = this.Average(this.GetAverageInfo(provider).TypeOfAverage)
            try
                DateTime.Now.AddSeconds seconds
            with :? ArgumentOutOfRangeException ->
                if seconds < 0.0 then DateTime.MinValue else DateTime.MaxValue

        member this.ToDecimal(provider: IFormatProvider) =
            // The Double conversion rounds Decimal.MinValue and
            // Decimal.MaxValue to invalid Decimal values, so the
            // following limits must be used.
            Convert.ToDecimal(this.CalcNLimitAverage(-79228162514264330000000000000.0, 79228162514264330000000000000.0, provider) )

        member this.ToDouble(provider: IFormatProvider) =
            this.Average(this.GetAverageInfo(provider).TypeOfAverage)

        member this.ToInt16(provider: IFormatProvider) =
            Convert.ToInt16(this.CalcNLimitAverage(float Int16.MinValue, float Int16.MaxValue, provider) )

        member this.ToInt32(provider: IFormatProvider) =
            Convert.ToInt32(this.CalcNLimitAverage(Int32.MinValue, Int32.MaxValue, provider) )

        member this.ToInt64(provider: IFormatProvider) =
            // The Double conversion rounds Int64.MinValue and
            // Int64.MaxValue to invalid Int64 values, so the following
            // limits must be used.
            Convert.ToInt64(this.CalcNLimitAverage(-9223372036854775000., 9223372036854775000., provider) )

        member this.ToSByte(provider: IFormatProvider) =
            Convert.ToSByte(this.CalcNLimitAverage(float SByte.MinValue, float SByte.MaxValue, provider) )

        member this.ToSingle(provider: IFormatProvider) =
            Convert.ToSingle(this.CalcNLimitAverage(float Single.MinValue, float Single.MaxValue, provider) )

        member this.ToUInt16(provider: IFormatProvider) =
            Convert.ToUInt16(this.CalcNLimitAverage(float UInt16.MinValue, float UInt16.MaxValue, provider) )

        member this.ToUInt32(provider: IFormatProvider) =
            Convert.ToUInt32(this.CalcNLimitAverage(float UInt32.MinValue, float UInt32.MaxValue, provider) )

        member this.ToUInt64(provider: IFormatProvider) =
            // The Double conversion rounds UInt64.MaxValue to an invalid
            // UInt64 value, so the following limit must be used.
            Convert.ToUInt64(this.CalcNLimitAverage(0, 18446744073709550000.0, provider) )

        member this.ToType(conversionType: Type, provider: IFormatProvider) =
            Convert.ChangeType(this.Average(this.GetAverageInfo(provider).TypeOfAverage), conversionType)

        member this.ToString(provider: IFormatProvider) =
            let avgType = this.GetAverageInfo(provider).TypeOfAverage
            $"( {avgType}: {this.Average avgType:G10} )"                

// Display a DataSet with three different format providers.
let displayDataSet (ds: DataSet) =
    let fmt obj1 obj2 obj3 obj4 = printfn $"{obj1,-12}{obj2,20}{obj3,20}{obj4,20}"
    let median = AverageInfo AverageType.Median
    let geMean =
        AverageInfo AverageType.GeometricMean

    // Display the dataset elements.
    if ds.Count > 0 then
        printf $"\nDataSet: [{ds[0]}"
        for i = 1 to ds.Count - 1 do
            printf $", {ds[i]}"
        printfn "]\n"

    fmt "Convert." "Default" "Geometric Mean" "Median"
    fmt "--------" "-------" "--------------" "------"
    fmt "ToBoolean"
        (Convert.ToBoolean(ds, null))
        (Convert.ToBoolean(ds, geMean))
        (Convert.ToBoolean(ds, median))
    fmt "ToByte"
        (Convert.ToByte(ds, null))
        (Convert.ToByte(ds, geMean))
        (Convert.ToByte(ds, median))
    fmt "ToChar"
        (Convert.ToChar(ds, null))
        (Convert.ToChar(ds, geMean))
        (Convert.ToChar(ds, median))
    printfn $"""{"ToDateTime",-12}{Convert.ToDateTime(ds, null).ToString "20:yyyy-MM-dd HH:mm:ss"}{Convert.ToDateTime(ds, geMean).ToString "20:yyyy-MM-dd HH:mm:ss"}{Convert.ToDateTime(ds, median).ToString "20:yyyy-MM-dd HH:mm:ss"}"""

    fmt "ToDecimal"
        (Convert.ToDecimal(ds, null))
        (Convert.ToDecimal(ds, geMean))
        (Convert.ToDecimal(ds, median))
    fmt "ToDouble"
        (Convert.ToDouble(ds, null))
        (Convert.ToDouble(ds, geMean))
        (Convert.ToDouble(ds, median))
    fmt "ToInt16"
        (Convert.ToInt16(ds, null))
        (Convert.ToInt16(ds, geMean))
        (Convert.ToInt16(ds, median))
    fmt "ToInt32"
        (Convert.ToInt32(ds, null))
        (Convert.ToInt32(ds, geMean))
        (Convert.ToInt32(ds, median))
    fmt "ToInt64"
        (Convert.ToInt64(ds, null))
        (Convert.ToInt64(ds, geMean))
        (Convert.ToInt64(ds, median))
    fmt "ToSByte"
        (Convert.ToSByte(ds, null))
        (Convert.ToSByte(ds, geMean))
        (Convert.ToSByte(ds, median))
    fmt "ToSingle"
        (Convert.ToSingle(ds, null))
        (Convert.ToSingle(ds, geMean))
        (Convert.ToSingle(ds, median))
    fmt "ToUInt16"
        (Convert.ToUInt16(ds, null))
        (Convert.ToUInt16(ds, geMean))
        (Convert.ToUInt16(ds, median))
    fmt "ToUInt32"
        (Convert.ToUInt32(ds, null))
        (Convert.ToUInt32(ds, geMean))
        (Convert.ToUInt32(ds, median))
    fmt "ToUInt64"
        (Convert.ToUInt64(ds, null))
        (Convert.ToUInt64(ds, geMean))
        (Convert.ToUInt64(ds, median))

printfn
    """This example of the Convert.To<Type>( object, IFormatprovider) methods 
generates the following output. The example displays the values 
returned by the methods, using several IFormatProvider objects.
"""

let ds1 = DataSet(10.5, 22.2, 45.9, 88.7, 156.05, 297.6)
displayDataSet ds1

let ds2 = DataSet(359999.95, 425000, 499999.5, 775000, 1695000)
displayDataSet ds2

// This example of the Convert.To<Type>( object, IFormatprovider) methods
// generates the following output. The example displays the values
// returned by the methods, using several IFormatProvider objects.
//
// DataSet: [10.5, 22.2, 45.9, 88.7, 156.05, 297.6]
//
// Convert.                 Default      Geometric Mean              Median
// --------                 -------      --------------              ------
// ToBoolean                   True                True                True
// ToByte                       103                  59                  67
// ToChar                         g                   ;                   C
// ToDateTime   2003-05-13 15:04:12 2003-05-13 15:03:28 2003-05-13 15:03:35
// ToDecimal       103.491666666667    59.4332135445164                67.3
// ToDouble        103.491666666667    59.4332135445164                67.3
// ToInt16                      103                  59                  67
// ToInt32                      103                  59                  67
// ToInt64                      103                  59                  67
// ToSByte                      103                  59                  67
// ToSingle                103.4917            59.43321                67.3
// ToUInt16                     103                  59                  67
// ToUInt32                     103                  59                  67
// ToUInt64                     103                  59                  67
//
// DataSet: [359999.95, 425000, 499999.5, 775000, 1695000]
//
// Convert.                 Default      Geometric Mean              Median
// --------                 -------      --------------              ------
// ToBoolean                   True                True                True
// ToByte                       255                 255                 255
// ToChar                         ?                   ?                   ?
// ToDateTime   2003-05-22 07:39:08 2003-05-20 22:28:45 2003-05-19 09:55:48
// ToDecimal              750999.89    631577.237188435            499999.5
// ToDouble               750999.89    631577.237188435            499999.5
// ToInt16                    32767               32767               32767
// ToInt32                   751000              631577              500000
// ToInt64                   751000              631577              500000
// ToSByte                      127                 127                 127
// ToSingle                750999.9            631577.3            499999.5
// ToUInt16                   65535               65535               65535
// ToUInt32                  751000              631577              500000
// ToUInt64                  751000              631577              500000
Imports System.Collections

Module IConvertibleProviderDemo

    ' Define the types of averaging available in the class 
    ' implementing IConvertible.
    Enum AverageType as Short
        None = 0
        GeometricMean = 1
        ArithmeticMean = 2
        Median = 3
    End Enum

    ' Pass an instance of this class to methods that require an 
    ' IFormatProvider. The class instance determines the type of 
    ' average to calculate.
    Public Class AverageInfo
        Implements IFormatProvider

        Protected  AvgType      As AverageType

        ' Specify the type of averaging in the constructor.
        Public Sub New( avgType As AverageType )
            Me.AvgType = avgType
        End Sub

        ' This method returns a reference to the containing object 
        ' if an object of AverageInfo type is requested. 
        Public Function GetFormat( argType As Type ) As Object _
            Implements IFormatProvider.GetFormat

            If argType Is GetType( AverageInfo ) Then
                Return Me
            Else
                Return Nothing
            End If
        End Function 

        ' Use this property to set or get the type of averaging.
        Public Property TypeOfAverage( ) As AverageType
            Get
                Return Me.AvgType
            End Get
            Set( ByVal value as AverageType )
                Me.AvgType = value
            End Set
        End Property
    End Class 

    ' This class encapsulates an array of Double values and implements 
    ' the IConvertible interface. Most of the IConvertible methods 
    ' return an average of the array elements in one of three types: 
    ' arithmetic mean, geometric mean, or median. 
    Public Class DataSet
        Implements IConvertible

        Protected data              As ArrayList
        Protected defaultProvider   As AverageInfo
           
        ' Construct the object and add an initial list of values.
        ' Create a default format provider.
        Public Sub New( ParamArray values( ) As Double )
            data = New ArrayList( values )
            defaultProvider = New AverageInfo( _
                AverageType.ArithmeticMean )  
        End Sub
           
        ' Add additional values with this method.
        Public Function Add( value As Double ) As Integer
            data.Add( value )
            Return data.Count
        End Function
           
        ' Get, set, and add values with this indexer property.
        Default Public Property Item(index As Integer) As Double
            Get
                If index >= 0 AndAlso index < data.Count Then
                    Return System.Convert.ToDouble( data( index ) )
                Else
                    Throw New InvalidOperationException( _
                        "[DataSet.get] Index out of range." )
                End If
            End Get
            Set
                If index >= 0 AndAlso index < data.Count Then
                    data( index ) = value
                 
                ElseIf index = data.Count Then
                    data.Add( value )
                Else
                    Throw New InvalidOperationException( _
                        "[DataSet.set] Index out of range." )
                End If
            End Set
        End Property
          
        ' This property returns the number of elements in the object.
        Public ReadOnly Property Count( ) As Integer
            Get
                Return data.Count
            End Get
        End Property

        ' This method calculates the average of the object's elements.
        Protected Function Average( ByVal avgType As AverageType ) As Double

            Dim SumProd As Double 
            Dim Index   As Integer

            If data.Count = 0 Then Return 0.0

            Select Case avgType
                
                Case AverageType.GeometricMean

                    SumProd = 1.0
                    For Index = 0 To data.Count - 1
                        SumProd *= data( Index )
                    Next Index
                    
                    ' This calculation will not fail with negative 
                    ' elements.
                    Return Math.Sign( SumProd ) * Math.Pow( _
                        Math.Abs( SumProd ), 1.0 / data.Count )

                Case AverageType.ArithmeticMean

                    SumProd = 0.0
                    For Index = 0 To data.Count - 1
                        SumProd += data( Index )
                    Next Index

                    Return SumProd / data.Count 

                Case AverageType.Median

                    If data.Count Mod 2 = 0 Then
                        Return ( data( data.Count \ 2 ) + _
                            data( data.Count \ 2 - 1 ) ) / 2.0
                    Else
                        Return data( data.Count \ 2 ) 
                    End If
            End Select
        End Function

        ' Get the AverageInfo object from the caller's format 
        ' provider, or use the local default.
        Protected Function GetAverageInfo( _
            provider As IFormatProvider ) As AverageInfo

            Dim avgInfo As AverageInfo = Nothing

            If Not provider Is Nothing Then
                avgInfo = provider.GetFormat( GetType( AverageInfo ) )
            End If

            Return IIf( avgInfo Is Nothing, defaultProvider, avgInfo )
            
        End Function           

        ' Calculate the average and limit the range.
        Protected Function CalcNLimitAverage( min As Double, _
            max As Double, provider as IFormatProvider ) As Double

            ' Get the format provider and calculate the average.
            Dim avgInfo As AverageInfo = GetAverageInfo( provider )
            Dim avg As Double = Average( avgInfo.TypeOfAverage )

            ' Limit the range, based on the minimum and maximum values 
            ' for the type.
            Return IIf( avg > max, max, IIf( avg < min, min, avg ) )

        End Function

        ' The following elements are required by IConvertible.

        ' None of these conversion functions throw exceptions. When
        ' the data is out of range for the type, the appropriate
        ' MinValue or MaxValue is used.
        Public Function GetTypeCode( ) As TypeCode _
            Implements IConvertible.GetTypeCode
            Return TypeCode.Object
        End Function

        Function ToBoolean( ByVal provider As IFormatProvider ) As _
            Boolean Implements IConvertible.ToBoolean

            ' ToBoolean is false if the dataset is empty.
            If data.Count <= 0 Then
                Return False

            ' For median averaging, ToBoolean is true if any 
            ' non-discarded elements are nonzero.
            ElseIf AverageType.Median = _
                GetAverageInfo( provider ).TypeOfAverage Then

                If data.Count Mod 2 = 0 Then
                    Return ( data( data.Count \ 2 ) <> 0.0 Or _
                        data( data.Count \ 2 - 1 ) <> 0.0 )
                Else
                    Return data( data.Count \ 2 ) <> 0.0
                End If

            ' For arithmetic or geometric mean averaging, ToBoolean is 
            ' true if any element of the dataset is nonzero.  
            Else
                Dim Index As Integer
                For Index = 0 To data.Count - 1
                    If data( Index ) <> 0.0 Then Return True
                Next Index
                Return False
            End If
        End Function

        Function ToByte( ByVal provider As IFormatProvider ) As Byte _
            Implements IConvertible.ToByte
            Return Convert.ToByte( CalcNLimitAverage( _
                Byte.MinValue, Byte.MaxValue, provider ) )
        End Function

        Function ToChar( ByVal provider As IFormatProvider ) As Char _
            Implements IConvertible.ToChar
            Return Convert.ToChar( Convert.ToUInt16( _
                CalcNLimitAverage( 0.0, &HFFFF, provider ) ) )
        End Function

        ' Convert to DateTime by adding the calculated average as 
        ' seconds to the current date and time. A valid DateTime is 
        ' always returned.
        Function ToDateTime( ByVal provider As IFormatProvider ) As _
            DateTime Implements IConvertible.ToDateTime
            Dim seconds As Double = Average( _
                GetAverageInfo( provider ).TypeOfAverage )
            Try
                Return DateTime.Now.AddSeconds( seconds )
            Catch ex As ArgumentOutOfRangeException 
                Return IIf( seconds < 0.0, DateTime.MinValue, _
                    DateTime.MaxValue )
            End Try
        End Function

        Function ToDecimal( ByVal provider As IFormatProvider ) As _
            Decimal Implements IConvertible.ToDecimal

            ' The Double conversion rounds Decimal.MinValue and
            ' Decimal.MaxValue to invalid Decimal values, so the 
            ' following limits must be used.
            Return Convert.ToDecimal( CalcNLimitAverage( _
                -79228162514264330000000000000.0, _
                79228162514264330000000000000.0, provider ) )
        End Function

        Function ToDouble( ByVal provider As IFormatProvider) As _
            Double Implements IConvertible.ToDouble
            Return Average( GetAverageInfo( provider ).TypeOfAverage )
        End Function

        Function ToInt16( ByVal provider As IFormatProvider ) As _
            Short Implements IConvertible.ToInt16
            Return Convert.ToInt16( CalcNLimitAverage( _
                Int16.MinValue, Int16.MaxValue, provider ) )
        End Function

        Function ToInt32( ByVal provider As IFormatProvider ) As _
            Integer Implements IConvertible.ToInt32
            Return Convert.ToInt32( CalcNLimitAverage( _
                Int32.MinValue, Int32.MaxValue, provider ) )
        End Function

        Function ToInt64( ByVal provider As IFormatProvider ) As Long _
            Implements IConvertible.ToInt64

            ' The Double conversion rounds Int64.MinValue and 
            ' Int64.MaxValue to invalid Long values, so the following 
            ' limits must be used.
            Return Convert.ToInt64( CalcNLimitAverage( _
                -9223372036854775000, 9223372036854775000, provider ) )
        End Function

        Function ToSByte( ByVal provider As IFormatProvider ) As _
            SByte Implements IConvertible.ToSByte

            ' SByte.MinValue and SByte.MaxValue are not defined in
            ' Visual Basic.
            Return Convert.ToSByte( CalcNLimitAverage( _
                -128, 127, provider ) )
        End Function

        Function ToSingle( ByVal provider As IFormatProvider ) As _
            Single Implements IConvertible.ToSingle
            Return Convert.ToSingle( CalcNLimitAverage( _
                Single.MinValue, Single.MaxValue, provider ) )
        End Function

        Function ToUInt16( ByVal provider As IFormatProvider ) As _
            UInt16 Implements IConvertible.ToUInt16

            ' UInt16.MinValue and UInt16.MaxValue are not defined in 
            ' Visual Basic.
            Return Convert.ToUInt16( CalcNLimitAverage( _
                0, &HFFFF, provider ) )
        End Function

        Function ToUInt32( ByVal provider As IFormatProvider ) As _
            UInt32 Implements IConvertible.ToUInt32

            ' UInt32.MinValue and UInt32.MaxValue are not defined in 
            ' Visual Basic.
            Return Convert.ToUInt32( CalcNLimitAverage( _
                0, 4294967295, provider ) )
        End Function

        Function ToUInt64( ByVal provider As IFormatProvider ) As _
            UInt64 Implements IConvertible.ToUInt64

            ' UInt64.MinValue and UInt64.MaxValue are not defined in 
            ' Visual Basic. The Double conversion would have rounded 
            ' UInt64.MaxValue, so the following limit must be used.
            Return Convert.ToUInt64( CalcNLimitAverage( _
                0, 18446744073709550000.0, provider ) )
        End Function

        Function ToType( ByVal conversionType As Type, _
            ByVal provider As IFormatProvider) As Object _
            Implements IConvertible.ToType
            Return Convert.ChangeType( Average( GetAverageInfo( _
                provider ).TypeOfAverage ), conversionType )
        End Function

        Overloads Function ToString( ByVal provider As IFormatProvider _
            ) As String Implements IConvertible.ToString
            Dim avgType as AverageType = _
                GetAverageInfo( provider ).TypeOfAverage
            Return String.Format( "( {0}: {1:G10} )", avgType, _
                Average( avgType ) )
        End Function
    End Class
   
    ' Display a DataSet with three different format providers.
    Sub DisplayDataSet( ds As DataSet )

        Dim fmt    As String      = "{0,-12}{1,20}{2,20}{3,20}"
        Dim median As AverageInfo = New AverageInfo( AverageType.Median )
        Dim geMean As AverageInfo = _
            New AverageInfo( AverageType.GeometricMean )
        Dim iX     As Integer

        ' Display the dataset elements.
        If ds.Count > 0 Then
            Console.Write( vbCrLf & "DataSet: [{0}", ds( 0 ) )
            For iX = 1 To ds.Count - 1
                Console.Write( ", {0}", ds( iX ) )
            Next iX
            Console.WriteLine( "]" & vbCrLf )
        End If

        Console.WriteLine( fmt, "Convert.", "Default", _
            "Geometric Mean", "Median" )
        Console.WriteLine( fmt, "--------", "-------", _
            "--------------", "------" )
        Console.WriteLine( fmt, "ToBoolean", _
            Convert.ToBoolean( ds, Nothing ), _
            Convert.ToBoolean( ds, geMean ), _
            Convert.ToBoolean( ds, median ) )
        Console.WriteLine( fmt, "ToByte", _
            Convert.ToByte( ds, Nothing ), _
            Convert.ToByte( ds, geMean ), _
            Convert.ToByte( ds, median ) )
        Console.WriteLine( fmt, "ToChar", _
            Convert.ToChar( ds, Nothing ), _
            Convert.ToChar( ds, geMean ), _
            Convert.ToChar( ds, median ) )
        Console.WriteLine( "{0,-12}{1,20:yyyy-MM-dd HH:mm:ss}" & _
            "{2,20:yyyy-MM-dd HH:mm:ss}{3,20:yyyy-MM-dd HH:mm:ss}", _
            "ToDateTime", Convert.ToDateTime( ds, Nothing ), _
            Convert.ToDateTime( ds, geMean ), _
            Convert.ToDateTime( ds, median ) )
        Console.WriteLine( fmt, "ToDecimal", _
            Convert.ToDecimal( ds, Nothing ), _
            Convert.ToDecimal( ds, geMean ), _
            Convert.ToDecimal( ds, median ) )
        Console.WriteLine( fmt, "ToDouble", _
            Convert.ToDouble( ds, Nothing ), _
            Convert.ToDouble( ds, geMean ), _
            Convert.ToDouble( ds, median ) )
        Console.WriteLine( fmt, "ToInt16", _
            Convert.ToInt16( ds, Nothing ), _
            Convert.ToInt16( ds, geMean ), _
            Convert.ToInt16( ds, median ) )
        Console.WriteLine( fmt, "ToInt32", _
            Convert.ToInt32( ds, Nothing ), _
            Convert.ToInt32( ds, geMean ), _
            Convert.ToInt32( ds, median ) )
        Console.WriteLine( fmt, "ToInt64", _
            Convert.ToInt64( ds, Nothing ), _
            Convert.ToInt64( ds, geMean ), _
            Convert.ToInt64( ds, median ) )
        Console.WriteLine( fmt, "ToSByte", _
            Convert.ToSByte( ds, Nothing ), _
            Convert.ToSByte( ds, geMean ), _
            Convert.ToSByte( ds, median ) )
        Console.WriteLine( fmt, "ToSingle", _
            Convert.ToSingle( ds, Nothing ), _
            Convert.ToSingle( ds, geMean ), _
            Convert.ToSingle( ds, median ) )
        Console.WriteLine( fmt, "ToUInt16", _
            Convert.ToUInt16( ds, Nothing ), _
            Convert.ToUInt16( ds, geMean ), _
            Convert.ToUInt16( ds, median ) )
        Console.WriteLine( fmt, "ToUInt32", _
            Convert.ToUInt32( ds, Nothing ), _
            Convert.ToUInt32( ds, geMean ), _
            Convert.ToUInt32( ds, median ) )
        Console.WriteLine( fmt, "ToUInt64", _
            Convert.ToUInt64( ds, Nothing ), _
            Convert.ToUInt64( ds, geMean ), _
            Convert.ToUInt64( ds, median ) )
    End Sub
   
    Sub Main( )
        Console.WriteLine( _
            "This example of the Convert.To<Type>( Object, " & _
            "IFormatProvider ) methods " & vbCrLf & "generates " & _
            "the following output. The example displays the " & _
            "values " & vbCrLf & "returned by the methods, " & _
            "using several IFormatProvider objects." & vbCrLf )
          
        Dim ds1 As New DataSet( 10.5, 22.2, 45.9, 88.7, 156.05, 297.6 )
        DisplayDataSet( ds1 )
          
        Dim ds2 As New DataSet( _
            359999.95, 425000, 499999.5, 775000, 1695000 )
        DisplayDataSet( ds2 )
    End Sub 
End Module 

' This example of the Convert.To<Type>( Object, IFormatProvider ) methods
' generates the following output. The example displays the values
' returned by the methods, using several IFormatProvider objects.
' 
' DataSet: [10.5, 22.2, 45.9, 88.7, 156.05, 297.6]
' 
' Convert.                 Default      Geometric Mean              Median
' --------                 -------      --------------              ------
' ToBoolean                   True                True                True
' ToByte                       103                  59                  67
' ToChar                         g                   ;                   C
' ToDateTime   2003-05-13 14:52:53 2003-05-13 14:52:09 2003-05-13 14:52:17
' ToDecimal       103.491666666667    59.4332135445164                67.3
' ToDouble        103.491666666667    59.4332135445164                67.3
' ToInt16                      103                  59                  67
' ToInt32                      103                  59                  67
' ToInt64                      103                  59                  67
' ToSByte                      103                  59                  67
' ToSingle                103.4917            59.43321                67.3
' ToUInt16                     103                  59                  67
' ToUInt32                     103                  59                  67
' ToUInt64                     103                  59                  67
' 
' DataSet: [359999.95, 425000, 499999.5, 775000, 1695000]
' 
' Convert.                 Default      Geometric Mean              Median
' --------                 -------      --------------              ------
' ToBoolean                   True                True                True
' ToByte                       255                 255                 255
' ToChar                         ?                   ?                   ?
' ToDateTime   2003-05-22 07:27:49 2003-05-20 22:17:27 2003-05-19 09:44:29
' ToDecimal              750999.89    631577.237188435            499999.5
' ToDouble               750999.89    631577.237188435            499999.5
' ToInt16                    32767               32767               32767
' ToInt32                   751000              631577              500000
' ToInt64                   751000              631577              500000
' ToSByte                      127                 127                 127
' ToSingle                750999.9            631577.3            499999.5
' ToUInt16                   65535               65535               65535
' ToUInt32                  751000              631577              500000
' ToUInt64                  751000              631577              500000

注解

返回值是调用 IConvertible.ToInt64 基础类型的 value方法的结果。

provider 使用户能够指定有关 的内容 value的区域性特定转换信息。 例如,如果 value 是 一个 String 表示数字的 , provider 则可提供有关用于表示该数字的表示法的区域性特定信息。

基类型忽略 provider;但是,如果 value 是实现 IConvertible 接口的用户定义类型,则可以使用 参数。

适用于

ToInt64(UInt64)

重要

此 API 不符合 CLS。

将指定的 64 位无符号整数的值转换为等效的 64 位有符号整数。

public:
 static long ToInt64(System::UInt64 value);
[System.CLSCompliant(false)]
public static long ToInt64 (ulong value);
[<System.CLSCompliant(false)>]
static member ToInt64 : uint64 -> int64
Public Shared Function ToInt64 (value As ULong) As Long

参数

value
UInt64

要转换的 64 位无符号整数。

返回

一个与 value 等效的 64 位带符号整数。

属性

例外

示例

以下示例尝试将无符号长整数数组中的每个元素转换为长整数。

ulong[] numbers = { UInt64.MinValue, 121, 340, UInt64.MaxValue };
long result;
foreach (ulong number in numbers)
{
   try {
      result = Convert.ToInt64(number);
      Console.WriteLine("Converted the {0} value {1} to a {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Int64 type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//    Converted the UInt64 value 0 to a Int32 value 0.
//    Converted the UInt64 value 121 to a Int32 value 121.
//    Converted the UInt64 value 340 to a Int32 value 340.
//    The UInt64 value 18446744073709551615 is outside the range of the Int64 type.
let numbers =
    [| UInt64.MinValue; 121uL; 340uL; UInt64.MaxValue |]

for number in numbers do
    try
        let result = Convert.ToInt64 number
        printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
    with :? OverflowException ->
        printfn $"The {number.GetType().Name} value {number} is outside the range of the Int64 type."
// The example displays the following output:
//    Converted the UInt64 value 0 to a Int32 value 0.
//    Converted the UInt64 value 121 to a Int32 value 121.
//    Converted the UInt64 value 340 to a Int32 value 340.
//    The UInt64 value 18446744073709551615 is outside the range of the Int64 type.
Dim numbers() As ULong = { UInt64.MinValue, 121, 340, UInt64.MaxValue }
Dim result As Long

For Each number As ULong In numbers
   Try
      result = Convert.ToInt64(number)
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Int64 type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'    Converted the UInt64 value 0 to the Int64 value 0.
'    Converted the UInt64 value 121 to the Int64 value 121.
'    Converted the UInt64 value 340 to the Int64 value 340.
'    The UInt64 value 18446744073709551615 is outside the range of the Int64 type.

适用于

ToInt64(UInt32)

重要

此 API 不符合 CLS。

将指定的 32 位无符号整数的值转换为等效的 64 位有符号整数。

public:
 static long ToInt64(System::UInt32 value);
[System.CLSCompliant(false)]
public static long ToInt64 (uint value);
[<System.CLSCompliant(false)>]
static member ToInt64 : uint32 -> int64
Public Shared Function ToInt64 (value As UInteger) As Long

参数

value
UInt32

要转换的 32 位无符号整数。

返回

一个与 value 等效的 64 位带符号整数。

属性

示例

以下示例将无符号整数数组中的每个元素转换为长整数。

uint[] numbers = { UInt32.MinValue, 121, 340, UInt32.MaxValue };
long result;
foreach (uint number in numbers)
{
   result = Convert.ToInt64(number);
   Console.WriteLine("Converted the {0} value {1:N0} to the {2} value {3:N0}.",
                     number.GetType().Name, number,
                     result.GetType().Name, result);
}
// The example displays the following output:
//    Converted the UInt32 value 0 to the Int64 value 0.
//    Converted the UInt32 value 121 to the Int64 value 121.
//    Converted the UInt32 value 340 to the Int64 value 340.
//    Converted the UInt32 value 4,294,967,295 to the Int64 value 4,294,967,295.
let numbers =
    [| UInt32.MinValue; 121u; 340u; UInt32.MaxValue |]

for number in numbers do
    try
        let result = Convert.ToInt64 number
        printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
    with :? OverflowException ->
        printfn $"The {number.GetType().Name} value {number} is outside the range of the Int64 type."
// The example displays the following output:
//    Converted the UInt32 value 0 to the Int64 value 0.
//    Converted the UInt32 value 121 to the Int64 value 121.
//    Converted the UInt32 value 340 to the Int64 value 340.
//    The UInt32 value 4294967295 is outside the range of the Int64 type.
Dim numbers() As UInteger = { UInt32.MinValue, 121, 340, UInt32.MaxValue }
Dim result As Long
For Each number As UInteger In numbers
   result = Convert.ToInt64(number)
   Console.WriteLine("Converted the {0} value {1:N0} to the {2} value {3:N0}.", _
                     number.GetType().Name, number, _
                     result.GetType().Name, result)
Next
' The example displays the following output:
'    Converted the UInt32 value 0 to the Int64 value 0.
'    Converted the UInt32 value 121 to the Int64 value 121.
'    Converted the UInt32 value 340 to the Int64 value 340.
'    Converted the UInt32 value 4,294,967,295 to the Int64 value 4,294,967,295.

适用于

ToInt64(UInt16)

重要

此 API 不符合 CLS。

将指定的 16 位无符号整数的值转换为等效的 64 位有符号整数。

public:
 static long ToInt64(System::UInt16 value);
[System.CLSCompliant(false)]
public static long ToInt64 (ushort value);
[<System.CLSCompliant(false)>]
static member ToInt64 : uint16 -> int64
Public Shared Function ToInt64 (value As UShort) As Long

参数

value
UInt16

要转换的 16 位无符号整数。

返回

一个与 value 等效的 64 位带符号整数。

属性

示例

以下示例将 16 位无符号整数数组中的每个元素转换为长整数。

ushort[] numbers = { UInt16.MinValue, 121, 340, UInt16.MaxValue };
long result;
foreach (ushort number in numbers)
{
   try {
      result = Convert.ToInt64(number);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Int64 type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//    Converted the UInt16 value 0 to the Int64 value 0.
//    Converted the UInt16 value 121 to the Int64 value 121.
//    Converted the UInt16 value 340 to the Int64 value 340.
//    Converted the UInt16 value 65535 to the Int64 value 65535.
let numbers =
    [| UInt16.MinValue; 121us; 340us; UInt16.MaxValue |]

for number in numbers do
    try
        let result = Convert.ToInt64 number
        printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
    with :? OverflowException ->
        printfn $"The {number.GetType().Name} value {number} is outside the range of the Int64 type."
// The example displays the following output:
//    Converted the UInt16 value 0 to the Int64 value 0.
//    Converted the UInt16 value 121 to the Int64 value 121.
//    Converted the UInt16 value 340 to the Int64 value 340.
//    Converted the UInt16 value 65535 to the Int64 value 65535.
Dim numbers() As UShort = { UInt16.MinValue, 121, 340, UInt16.MaxValue }
Dim result As Long
For Each number As UShort In numbers
   Try
      result = Convert.ToInt64(number)
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Int64 type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'    Converted the UInt16 value 0 to the Int64 value 0.
'    Converted the UInt16 value 121 to the Int64 value 121.
'    Converted the UInt16 value 340 to the Int64 value 340.
'    Converted the UInt16 value 65535 to the Int64 value 65535.

适用于

ToInt64(String)

将数字的指定字符串表示形式转换为等效的 64 位带符号整数。

public:
 static long ToInt64(System::String ^ value);
public static long ToInt64 (string value);
public static long ToInt64 (string? value);
static member ToInt64 : string -> int64
Public Shared Function ToInt64 (value As String) As Long

参数

value
String

包含要转换的数字的字符串。

返回

一个与 value 中数字等效的 64 位带符号整数,如果 valuenull,则为 0(零)。

例外

value 不由一个可选符号后跟一系列数字 (0-9) 组成。

示例

以下示例尝试将数值字符串数组中的每个元素转换为长整数。

string[] values = { "One", "1.34e28", "-26.87", "-18", "-6.00",
                    " 0", "137", "1601.9", Int32.MaxValue.ToString() };
long result;

foreach (string value in values)
{
   try {
      result = Convert.ToInt64(value);
      Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.",
                        value.GetType().Name, value, result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("{0} is outside the range of the Int64 type.", value);
   }
   catch (FormatException) {
      Console.WriteLine("The {0} value '{1}' is not in a recognizable format.",
                        value.GetType().Name, value);
   }
}
// The example displays the following output:
//    The String value 'One' is not in a recognizable format.
//    The String value '1.34e28' is not in a recognizable format.
//    The String value '-26.87' is not in a recognizable format.
//    Converted the String value '-18' to the Int64 value -18.
//    The String value '-6.00' is not in a recognizable format.
//    Converted the String value ' 0' to the Int64 value 0.
//    Converted the String value '137' to the Int64 value 137.
//    The String value '1601.9' is not in a recognizable format.
//    Converted the String value '2147483647' to the Int64 value 2147483647.
let values = 
    [| "One"; "1.34e28"; "-26.87"; "-18"; "-6.00"
       " 0"; "137"; "1601.9"; string Int32.MaxValue |]

for value in values do
    try
        let result = Convert.ToInt64 value
        printfn $"Converted the {value.GetType().Name} value {value} to the {result.GetType().Name} value {result}."
    with
    | :? OverflowException ->
        printfn $"{value} is outside the range of the Int64 type."
    | :? FormatException ->
        printfn $"The {value.GetType().Name} value '{value}' is not in a recognizable format."
// The example displays the following output:
//    The String value 'One' is not in a recognizable format.
//    The String value '1.34e28' is not in a recognizable format.
//    The String value '-26.87' is not in a recognizable format.
//    Converted the String value '-18' to the Int64 value -18.
//    The String value '-6.00' is not in a recognizable format.
//    Converted the String value ' 0' to the Int64 value 0.
//    Converted the String value '137' to the Int64 value 137.
//    The String value '1601.9' is not in a recognizable format.
//    Converted the String value '2147483647' to the Int64 value 2147483647.
Dim values() As String = { "One", "1.34e28", "-26.87", "-18", "-6.00", _
                           " 0", "137", "1601.9", Int32.MaxValue.ToString() }
Dim result As Long

For Each value As String In values
   Try
      result = Convert.ToInt64(value)
      Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.", _
                        value.GetType().Name, value, result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("{0} is outside the range of the Int64 type.", value)
   Catch e As FormatException
      Console.WriteLine("The {0} value '{1}' is not in a recognizable format.", _
                        value.GetType().Name, value)
   End Try
Next
' The example displays the following output:
'    The String value 'One' is not in a recognizable format.
'    The String value '1.34e28' is not in a recognizable format.
'    The String value '-26.87' is not in a recognizable format.
'    Converted the String value '-18' to the Int64 value -18.
'    The String value '-6.00' is not in a recognizable format.
'    Converted the String value ' 0' to the Int64 value 0.
'    Converted the String value '137' to the Int64 value 137.
'    The String value '1601.9' is not in a recognizable format.
'    Converted the String value '2147483647' to the Int64 value 2147483647.

注解

ToInt64(String)使用 方法等效于将 传递给 valueInt64.Parse(String) 方法。 value 通过使用当前区域性的格式设置约定进行解释。

如果希望在转换失败时不处理异常,可以改为调用 Int64.TryParse 方法。 它返回一个 Boolean 值,该值指示转换是成功还是失败。

适用于

ToInt64(SByte)

重要

此 API 不符合 CLS。

将指定的 8 位带符号整数的值转换为等效的 64 位带符号整数。

public:
 static long ToInt64(System::SByte value);
[System.CLSCompliant(false)]
public static long ToInt64 (sbyte value);
[<System.CLSCompliant(false)>]
static member ToInt64 : sbyte -> int64
Public Shared Function ToInt64 (value As SByte) As Long

参数

value
SByte

要转换的 8 位带符号整数。

返回

一个与 value 等效的 64 位带符号整数。

属性

示例

以下示例将带符号字节数组中的每个元素转换为长整数。

sbyte[] numbers = { SByte.MinValue, -1, 0, 10, SByte.MaxValue };
long result;

foreach (sbyte number in numbers)
{
   result = Convert.ToInt64(number);
   Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                     number.GetType().Name, number,
                     result.GetType().Name, result);
}
// The example displays the following output:
//       Converted the SByte value -128 to the Int64 value -128.
//       Converted the SByte value -1 to the Int64 value -1.
//       Converted the SByte value 0 to the Int64 value 0.
//       Converted the SByte value 10 to the Int64 value 10.
//       Converted the SByte value 127 to the Int64 value 127.
let numbers =
    [| SByte.MinValue; -1y; 0y; 10y; SByte.MaxValue |]

for number in numbers do
    let result = Convert.ToInt64 number
    printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
// The example displays the following output:
//       Converted the SByte value -128 to the Int64 value -128.
//       Converted the SByte value -1 to the Int64 value -1.
//       Converted the SByte value 0 to the Int64 value 0.
//       Converted the SByte value 10 to the Int64 value 10.
//       Converted the SByte value 127 to the Int64 value 127.
Dim numbers() As SByte = { SByte.MinValue, -1, 0, 10, SByte.MaxValue }
Dim result As Long

For Each number As SByte In numbers
   result = Convert.ToInt64(number)
   Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.", _
                     number.GetType().Name, number, _
                     result.GetType().Name, result)
Next
' The example displays the following output:
'       Converted the SByte value -128 to the Int64 value -128.
'       Converted the SByte value -1 to the Int64 value -1.
'       Converted the SByte value 0 to the Int64 value 0.
'       Converted the SByte value 10 to the Int64 value 10.
'       Converted the SByte value 127 to the Int64 value 127.

适用于

ToInt64(Object)

将指定对象的值转换为 64 位带符号整数。

public:
 static long ToInt64(System::Object ^ value);
public static long ToInt64 (object value);
public static long ToInt64 (object? value);
static member ToInt64 : obj -> int64
Public Shared Function ToInt64 (value As Object) As Long

参数

value
Object

用于实现 IConvertible 接口的对象,或为 null

返回

一个与 value 等效的 64 位带符号整数,如果 valuenull,则为零。

例外

value 的格式不正确。

value 不实现 IConvertible 接口。

不支持该转换。

示例

以下示例尝试将对象数组中的每个元素转换为长整型。

object[] values = { true, -12, 163, 935, 'x', new DateTime(2009, 5, 12),
                    "104", "103.0", "-1",
                    "1.00e2", "One", 1.00e2, 16.3e42};
long result;

foreach (object value in values)
{
   try {
      result = Convert.ToInt64(value);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        value.GetType().Name, value,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Int64 type.",
                        value.GetType().Name, value);
   }
   catch (FormatException) {
      Console.WriteLine("The {0} value {1} is not in a recognizable format.",
                        value.GetType().Name, value);
   }
   catch (InvalidCastException) {
      Console.WriteLine("No conversion to an Int64 exists for the {0} value {1}.",
                        value.GetType().Name, value);
   }
}
// The example displays the following output:
//    Converted the Boolean value True to the Int64 value 1.
//    Converted the Int32 value -12 to the Int64 value -12.
//    Converted the Int32 value 163 to the Int64 value 163.
//    Converted the Int32 value 935 to the Int64 value 935.
//    Converted the Char value x to the Int64 value 120.
//    No conversion to an Int64 exists for the DateTime value 5/12/2009 12:00:00 AM.
//    Converted the String value 104 to the Int64 value 104.
//    The String value 103.0 is not in a recognizable format.
//    Converted the String value -1 to the Int64 value -1.
//    The String value 1.00e2 is not in a recognizable format.
//    The String value One is not in a recognizable format.
//    Converted the Double value 100 to the Int64 value 100.
//    The Double value 1.63E+43 is outside the range of the Int64 type.
let values: obj[] = 
    [| true; -12; 163; 935; 'x'; DateTime(2009, 5, 12)
       "104"; "103.0"; "-1"
       "1.00e2"; "One"; 1.00e2; 16.3e42 |]

for value in values do
    try
        let result = Convert.ToInt64 value
        printfn $"Converted the {value.GetType().Name} value {value} to the {result.GetType().Name} value {result}."
    with 
    | :? OverflowException ->
        printfn $"The {value.GetType().Name} value {value} is outside the range of the Int64 type."
    | :? FormatException ->
        printfn $"The {value.GetType().Name} value {value} is not in a recognizable format."
    | :? InvalidCastException ->
        printfn $"No conversion to an Int64 exists for the {value.GetType().Name} value {value}."
// The example displays the following output:
//    Converted the Boolean value True to the Int64 value 1.
//    Converted the Int32 value -12 to the Int64 value -12.
//    Converted the Int32 value 163 to the Int64 value 163.
//    Converted the Int32 value 935 to the Int64 value 935.
//    Converted the Char value x to the Int64 value 120.
//    No conversion to an Int64 exists for the DateTime value 5/12/2009 12:00:00 AM.
//    Converted the String value 104 to the Int64 value 104.
//    The String value 103.0 is not in a recognizable format.
//    Converted the String value -1 to the Int64 value -1.
//    The String value 1.00e2 is not in a recognizable format.
//    The String value One is not in a recognizable format.
//    Converted the Double value 100 to the Int64 value 100.
//    The Double value 1.63E+43 is outside the range of the Int64 type.
Dim values() As Object = { True, -12, 163, 935, "x"c, #5/12/2009#, _
                           "104", "103.0", "-1", _
                           "1.00e2", "One", 1.00e2, 16.3e42}
Dim result As Long

For Each value As Object In values
   Try
      result = Convert.ToInt64(value)
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.", _
                        value.GetType().Name, value, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Int64 type.", _
                        value.GetType().Name, value)
   Catch e As FormatException
      Console.WriteLine("The {0} value {1} is not in a recognizable format.", _
                        value.GetType().Name, value)
   Catch e As InvalidCastException
      Console.WriteLine("No conversion to an Int64 exists for the {0} value {1}.", _
                        value.GetType().Name, value)

   End Try
Next
' The example displays the following output:
'    Converted the Boolean value True to the Int64 value 1.
'    Converted the Int64 value -12 to the Int64 value -12.
'    Converted the Int64 value 163 to the Int64 value 163.
'    Converted the Int64 value 935 to the Int64 value 935.
'    Converted the Char value x to the Int64 value 120.
'    No conversion to an Int64 exists for the DateTime value 5/12/2009 12:00:00 AM.
'    Converted the String value 104 to the Int64 value 104.
'    The String value 103.0 is not in a recognizable format.
'    Converted the String value -1 to the Int64 value -1.
'    The String value 1.00e2 is not in a recognizable format.
'    The String value One is not in a recognizable format.
'    Converted the Double value 100 to the Int64 value 100.
'    The Double value 1.63E+43 is outside the range of the Int64 type.

注解

如果 value 不是 null,则此方法包装对 IConvertible.ToInt64 的基础类型的 实现的 value调用。

适用于

ToInt64(Int64)

返回指定的 64 位有符号整数;不执行实际的转换。

public:
 static long ToInt64(long value);
public static long ToInt64 (long value);
static member ToInt64 : int64 -> int64
Public Shared Function ToInt64 (value As Long) As Long

参数

value
Int64

64 位带符号整数。

返回

不经更改即返回 value

示例

以下示例将整数数组中的每个元素转换为长整型。

int[] numbers = { Int32.MinValue, -1, 0, 121, 340, Int32.MaxValue };
long result;
foreach (int number in numbers)
{
   result = Convert.ToInt64(number);
   Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                     number.GetType().Name, number,
                     result.GetType().Name, result);
}
// The example displays the following output:
//    Converted the Int32 value -2147483648 to the Int64 value -2147483648.
//    Converted the Int32 value -1 to the Int64 value -1.
//    Converted the Int32 value 0 to the Int64 value 0.
//    Converted the Int32 value 121 to the Int64 value 121.
//    Converted the Int32 value 340 to the Int64 value 340.
//    Converted the Int32 value 2147483647 to the Int64 value 2147483647.
let numbers =
    [| Int32.MinValue; -1; 0; 121; 340; Int32.MaxValue |]

for number in numbers do
    try
        let result = Convert.ToInt64 number
        printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
    with :? OverflowException ->
        printfn $"The {number.GetType().Name} value {number} is outside the range of the Int64 type."
// The example displays the following output:
//    The Int64 value -9223372036854775808 is outside the range of the Int64 type.
//    Converted the Int32 value -1 to the Int64 value -1.
//    Converted the Int32 value 0 to the Int64 value 0.
//    Converted the Int32 value 121 to the Int64 value 121.
//    Converted the Int32 value 340 to the Int64 value 340.
//    The Int64 value 9223372036854775807 is outside the range of the Int64 type.
Dim numbers() As Integer = { Int32.MinValue, -1, 0, 121, 340, Int32.MaxValue }
Dim result As Long
For Each number As Integer In numbers
   result = Convert.ToInt64(number)
   Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.", _
                     number.GetType().Name, number, _
                     result.GetType().Name, result)
Next
' The example displays the following output:
'    Converted the Int32 value -2147483648 to the Int64 value -2147483648.
'    Converted the Int32 value -1 to the Int64 value -1.
'    Converted the Int32 value 0 to the Int64 value 0.
'    Converted the Int32 value 121 to the Int64 value 121.
'    Converted the Int32 value 340 to the Int64 value 340.
'    Converted the Int32 value 2147483647 to the Int64 value 2147483647.

适用于

ToInt64(Byte)

将指定的 8 位无符号整数的值转换为等效的 64 位有符号整数。

public:
 static long ToInt64(System::Byte value);
public static long ToInt64 (byte value);
static member ToInt64 : byte -> int64
Public Shared Function ToInt64 (value As Byte) As Long

参数

value
Byte

要转换的 8 位无符号整数。

返回

一个与 value 等效的 64 位带符号整数。

示例

以下示例将字节数组中的每个元素转换为长整数。

byte[] bytes = { Byte.MinValue, 14, 122, Byte.MaxValue};
long result;

foreach (byte byteValue in bytes)
{
   result = Convert.ToInt64(byteValue);
   Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                     byteValue.GetType().Name, byteValue,
                     result.GetType().Name, result);
}
// The example displays the following output:
//       Converted the Byte value 0 to the Int64 value 0.
//       Converted the Byte value 14 to the Int64 value 14.
//       Converted the Byte value 122 to the Int64 value 122.
//       Converted the Byte value 255 to the Int64 value 255.
let bytes = 
    [| Byte.MinValue; 14uy; 122uy; Byte.MaxValue |]

for byteValue in bytes do
    let result = Convert.ToInt64 byteValue
    printfn $"Converted the {byteValue.GetType().Name} value {byteValue} to the {result.GetType().Name} value {result}."
// The example displays the following output:
//       Converted the Byte value 0 to the Int64 value 0.
//       Converted the Byte value 14 to the Int64 value 14.
//       Converted the Byte value 122 to the Int64 value 122.
//       Converted the Byte value 255 to the Int64 value 255.
Dim bytes() As Byte = { Byte.MinValue, 14, 122, Byte.MaxValue}
Dim result As Long

For Each byteValue As Byte In bytes
   result = Convert.ToInt64(byteValue)
   Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.", _
                     byteValue.GetType().Name, byteValue, _
                     result.GetType().Name, result)
Next
' The example displays the following output:
'    Converted the Byte value 0 to the Int64 value 0.
'    Converted the Byte value 14 to the Int64 value 14.
'    Converted the Byte value 122 to the Int64 value 122.
'    Converted the Byte value 255 to the Int64 value 255.

适用于

ToInt64(Char)

将指定的 Unicode 字符的值转换为等效的 64 位有符号整数。

public:
 static long ToInt64(char value);
public static long ToInt64 (char value);
static member ToInt64 : char -> int64
Public Shared Function ToInt64 (value As Char) As Long

参数

value
Char

要转换的 Unicode 字符。

返回

一个与 value 等效的 64 位带符号整数。

示例

以下示例将数组中的每个 Char 元素转换为长整数。

char[] chars = { 'a', 'z', '\u0007', '\u03FF',
                 '\u7FFF', '\uFFFE' };
long result;

foreach (char ch in chars)
{
   result = Convert.ToInt64(ch);
   Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.",
                     ch.GetType().Name, ch,
                     result.GetType().Name, result);
}
// The example displays the following output:
//       Converted the Char value 'a' to the Int64 value 97.
//       Converted the Char value 'z' to the Int64 value 122.
//       Converted the Char value '' to the Int64 value 7.
//       Converted the Char value 'Ͽ' to the Int64 value 1023.
//       Converted the Char value '翿' to the Int64 value 32767.
//       Converted the Char value '' to the Int64 value 65534.
let chars = 
    [| 'a'; 'z'; '\u0007'; '\u03FF'; '\u7FFF'; '\uFFFE' |]

for ch in chars do
    try
        let result = Convert.ToInt64 ch
        printfn $"Converted the {ch.GetType().Name} value '{ch}' to the {result.GetType().Name} value {result}."
    with :? OverflowException ->
        printfn $"Unable to convert u+{int ch:X4} to an Int32."
// The example displays the following output:
//       Converted the Char value 'a' to the Int64 value 97.
//       Converted the Char value 'z' to the Int64 value 122.
//       Converted the Char value '' to the Int64 value 7.
//       Converted the Char value 'Ͽ' to the Int64 value 1023.
//       Converted the Char value '翿' to the Int64 value 32767.
//       Converted the Char value '' to the Int64 value 65534.
Dim chars() As Char = { "a"c, "z"c, ChrW(7), ChrW(1023), _
                        ChrW(Short.MaxValue), ChrW(&hFFFE) }
Dim result As Long

For Each ch As Char in chars
   result = Convert.ToInt64(ch)
   Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.", _
                     ch.GetType().Name, ch, _
                     result.GetType().Name, result)
Next
' The example displays the following output:
'       Converted the Char value 'a' to the Int64 value 97.
'       Converted the Char value 'z' to the Int64 value 122.
'       Converted the Char value '' to the Int64 value 7.
'       Converted the Char value 'Ͽ' to the Int64 value 1023.
'       Converted the Char value '翿' to the Int64 value 32767.
'       Converted the Char value '' to the Int64 value 65534.

适用于

ToInt64(DateTime)

调用此方法始终引发 InvalidCastException

public:
 static long ToInt64(DateTime value);
public static long ToInt64 (DateTime value);
static member ToInt64 : DateTime -> int64
Public Shared Function ToInt64 (value As DateTime) As Long

参数

value
DateTime

要转换的日期和时间值。

返回

不支持此转换。 不返回任何值。

例外

不支持此转换。

适用于

ToInt64(Boolean)

将指定的布尔值转换为等效的 64 位带符号整数。

public:
 static long ToInt64(bool value);
public static long ToInt64 (bool value);
static member ToInt64 : bool -> int64
Public Shared Function ToInt64 (value As Boolean) As Long

参数

value
Boolean

要转换的布尔值。

返回

如果 valuetrue,则为数字 1;否则,为 0。

示例

以下示例将 Booleantruefalse 转换为长整数。

bool falseFlag = false;
bool trueFlag = true;

Console.WriteLine("{0} converts to {1}.", falseFlag,
                  Convert.ToInt64(falseFlag));
Console.WriteLine("{0} converts to {1}.", trueFlag,
                  Convert.ToInt64(trueFlag));
// The example displays the following output:
//       False converts to 0.
//       True converts to 1.
let falseFlag = false
let trueFlag = true

printfn $"{falseFlag} converts to {Convert.ToInt64 falseFlag}."
printfn $"{trueFlag} converts to {Convert.ToInt64 trueFlag}."
// The example displays the following output:
//       False converts to 0.
//       True converts to 1.
Dim falseFlag As Boolean = False
Dim trueFlag As Boolean = True

Console.WriteLine("{0} converts to {1}.", falseFlag, _
                  Convert.ToInt64(falseFlag))
Console.WriteLine("{0} converts to {1}.", trueFlag, _
                  Convert.ToInt64(trueFlag))
' The example displays the following output:
'       False converts to 0.
'       True converts to 1.

适用于

ToInt64(Double)

将指定的双精度浮点数的值转换为等效的 64 位带符号整数。

public:
 static long ToInt64(double value);
public static long ToInt64 (double value);
static member ToInt64 : double -> int64
Public Shared Function ToInt64 (value As Double) As Long

参数

value
Double

要转换的双精度浮点数。

返回

value,舍入为最接近的 64 位有符号整数。 如果 value 为两个整数中间的数字,则返回二者中的偶数;即 4.5 转换为 4,而 5.5 转换为 6。

例外

value 大于 Int64.MaxValue 或小于 Int64.MinValue

示例

以下示例尝试将值数组 Double 中的每个元素转换为长整数。

double[] values= { Double.MinValue, -1.38e10, -1023.299, -12.98,
                   0, 9.113e-16, 103.919, 17834.191, Double.MaxValue };
long result;

foreach (double value in values)
{
   try {
      result = Convert.ToInt64(value);
      Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.",
                        value.GetType().Name, value,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("{0} is outside the range of the Int64 type.", value);
   }
}
//    -1.7976931348623157E+308 is outside the range of the Int64 type.
//    Converted the Double value '-13800000000' to the Int64 value -13800000000.
//    Converted the Double value '-1023.299' to the Int64 value -1023.
//    Converted the Double value '-12.98' to the Int64 value -13.
//    Converted the Double value '0' to the Int64 value 0.
//    Converted the Double value '9.113E-16' to the Int64 value 0.
//    Converted the Double value '103.919' to the Int64 value 104.
//    Converted the Double value '17834.191' to the Int64 value 17834.
//    1.7976931348623157E+308 is outside the range of the Int64 type.
let values = 
    [| Double.MinValue; -1.38e10; -1023.299; -12.98
       0; 9.113e-16; 103.919; 17834.191; Double.MaxValue |]

for value in values do
    try
        let result = Convert.ToInt64 value
        printfn $"Converted the {value.GetType().Name} value '{value}' to the {result.GetType().Name} value {result}."
    with :? OverflowException ->
        printfn $"{value} is outside the range of the Int64 type."
//    -1.79769313486232E+308 is outside the range of the Int64 type.
//    -13800000000 is outside the range of the Int64 type.
//    Converted the Double value '-1023.299' to the Int64 value -1023.
//    Converted the Double value '-12.98' to the Int64 value -13.
//    Converted the Double value '0' to the Int64 value 0.
//    Converted the Double value '9.113E-16' to the Int64 value 0.
//    Converted the Double value '103.919' to the Int64 value 104.
//    Converted the Double value '17834.191' to the Int64 value 17834.
//    1.79769313486232E+308 is outside the range of the Int64 type.
Dim values() As Double = { Double.MinValue, -1.38e10, -1023.299, -12.98, _
                           0, 9.113e-16, 103.919, 17834.191, Double.MaxValue }
Dim result As Long

For Each value As Double In values
   Try
      result = Convert.ToInt64(value)
      Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.", _
                        value.GetType().Name, value, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("{0} is outside the range of the Int64 type.", value)
   End Try
Next
'    -1.79769313486232E+308 is outside the range of the Int64 type.
'    Converted the Double value '-13800000000' to the Int64 value -13800000000.
'    Converted the Double value '-1023.299' to the Int64 value -1023.
'    Converted the Double value '-12.98' to the Int64 value -13.
'    Converted the Double value '0' to the Int64 value 0.
'    Converted the Double value '9.113E-16' to the Int64 value 0.
'    Converted the Double value '103.919' to the Int64 value 104.
'    Converted the Double value '17834.191' to the Int64 value 17834.
'    1.79769313486232E+308 is outside the range of the Int64 type.

另请参阅

适用于

ToInt64(Int16)

将指定的 16 位有符号整数的值转换为等效的 64 位有符号整数。

public:
 static long ToInt64(short value);
public static long ToInt64 (short value);
static member ToInt64 : int16 -> int64
Public Shared Function ToInt64 (value As Short) As Long

参数

value
Int16

要转换的 16 位带符号整数。

返回

一个与 value 等效的 64 位带符号整数。

示例

以下示例将 16 位整数数组中的每个元素转换为长整数。

short[] numbers= { Int16.MinValue, -1, 0, 121, 340, Int16.MaxValue };
long result;

foreach (short number in numbers)
{
   result = Convert.ToInt64(number);
   Console.WriteLine("Converted the {0} value {1} to a {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
}
// The example displays the following output:
//    Converted the Int16 value -32768 to a Int32 value -32768.
//    Converted the Int16 value -1 to a Int32 value -1.
//    Converted the Int16 value 0 to a Int32 value 0.
//    Converted the Int16 value 121 to a Int32 value 121.
//    Converted the Int16 value 340 to a Int32 value 340.
//    Converted the Int16 value 32767 to a Int32 value 32767.
let numbers = 
    [| Int16.MinValue; -1s; 0s; 121s; 340s; Int16.MaxValue |]

for number in numbers do
    let result = Convert.ToInt64 number
    printfn $"Converted the {number.GetType().Name} value {number} to a {result.GetType().Name} value {result}."
// The example displays the following output:
//    Converted the Int16 value -32768 to a Int64 value -32768.
//    Converted the Int16 value -1 to a Int64 value -1.
//    Converted the Int16 value 0 to a Int64 value 0.
//    Converted the Int16 value 121 to a Int64 value 121.
//    Converted the Int16 value 340 to a Int64 value 340.
//    Converted the Int16 value 32767 to a Int64 value 32767.
Dim numbers() As Short = { Int16.MinValue, -1, 0, 121, 340, Int16.MaxValue }
Dim result As Long

For Each number As Short In numbers
   result = Convert.ToInt64(number)
   Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
Next
' The example displays the following output:
'    Converted the Int16 value -32768 to the Int64 value -32768.
'    Converted the Int16 value -1 to the Int64 value -1.
'    Converted the Int16 value 0 to the Int64 value 0.
'    Converted the Int16 value 121 to the Int64 value 121.
'    Converted the Int16 value 340 to the Int64 value 340.
'    Converted the Int16 value 32767 to the Int64 value 32767.

适用于

ToInt64(Int32)

将指定的 32 位有符号整数的值转换为等效的 64 位有符号整数。

public:
 static long ToInt64(int value);
public static long ToInt64 (int value);
static member ToInt64 : int -> int64
Public Shared Function ToInt64 (value As Integer) As Long

参数

value
Int32

要转换的 32 位带符号整数。

返回

一个与 value 等效的 64 位带符号整数。

适用于

ToInt64(Decimal)

将指定的十进制数的值转换为等效的 64 位带符号整数。

public:
 static long ToInt64(System::Decimal value);
public static long ToInt64 (decimal value);
static member ToInt64 : decimal -> int64
Public Shared Function ToInt64 (value As Decimal) As Long

参数

value
Decimal

要转换的十进制数。

返回

value,舍入为最接近的 64 位有符号整数。 如果 value 为两个整数中间的数字,则返回二者中的偶数;即 4.5 转换为 4,而 5.5 转换为 6。

例外

value 大于 Int64.MaxValue 或小于 Int64.MinValue

示例

以下示例尝试将值数组 Decimal 中的每个元素转换为长整数。

decimal[] values= { Decimal.MinValue, -1034.23m, -12m, 0m, 147m,
                    199.55m, 9214.16m, Decimal.MaxValue };
long result;

foreach (decimal value in values)
{
   try {
      result = Convert.ToInt64(value);
      Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.",
                        value.GetType().Name, value,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("{0} is outside the range of the Int64 type.",
                        value);
   }
}
// The example displays the following output:
//    -79228162514264337593543950335 is outside the range of the Int64 type.
//    Converted the Decimal value '-1034.23' to the Int64 value -1034.
//    Converted the Decimal value '-12' to the Int64 value -12.
//    Converted the Decimal value '0' to the Int64 value 0.
//    Converted the Decimal value '147' to the Int64 value 147.
//    Converted the Decimal value '199.55' to the Int64 value 200.
//    Converted the Decimal value '9214.16' to the Int64 value 9214.
//    79228162514264337593543950335 is outside the range of the Int64 type.
let values = 
    [| Decimal.MinValue; -1034.23m; -12m; 0m; 147m
       199.55m; 9214.16m; Decimal.MaxValue |]

for value in values do
    try
        let result = Convert.ToInt64 value
        printfn $"Converted the {value.GetType().Name} value '{value}' to the {result.GetType().Name} value {result}."
    with :? OverflowException ->
        printfn $"{value} is outside the range of the Int64 type."
// The example displays the following output:
//    -79228162514264337593543950335 is outside the range of the Int64 type.
//    Converted the Decimal value '-1034.23' to the Int64 value -1034.
//    Converted the Decimal value '-12' to the Int64 value -12.
//    Converted the Decimal value '0' to the Int64 value 0.
//    Converted the Decimal value '147' to the Int64 value 147.
//    Converted the Decimal value '199.55' to the Int64 value 200.
//    Converted the Decimal value '9214.16' to the Int64 value 9214.
//    79228162514264337593543950335 is outside the range of the Int64 type.
Dim values() As Decimal = { Decimal.MinValue, -1034.23d, -12d, 0d, 147d, _
                            199.55d, 9214.16d, Decimal.MaxValue }
Dim result As Long

For Each value As Decimal In values
   Try
      result = Convert.ToInt64(value)
      Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.", _
                        value.GetType().Name, value, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("{0} is outside the range of the Int64 type.", _
                        value)
   End Try
Next
' The example displays the following output:
'    -79228162514264337593543950335 is outside the range of the Int64 type.
'    Converted the Decimal value '-1034.23' to the Int64 value -1034.
'    Converted the Decimal value '-12' to the Int64 value -12.
'    Converted the Decimal value '0' to the Int64 value 0.
'    Converted the Decimal value '147' to the Int64 value 147.
'    Converted the Decimal value '199.55' to the Int64 value 200.
'    Converted the Decimal value '9214.16' to the Int64 value 9214.
'    79228162514264337593543950335 is outside the range of the Int64 type.

另请参阅

适用于