Convert.ToSingle 方法

参考

定义

命名空间:: System

程序集:: System.Runtime.Extensions.dll

程序集:: System.Runtime.dll

程序集:: mscorlib.dll

程序集:: netstandard.dll

重要

一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。

将指定的值转换为单精度浮点数。

重载

ToSingle(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单精度浮点数。
ToSingle(SByte)	将指定的 8 位带符号整数的值转换为等效的单精度浮点数。
ToSingle(Object, IFormatProvider)	使用指定的区域性特定格式设置信息，将指定对象的值转换为单精度浮点数。
ToSingle(UInt64)	将指定的 64 位无符号整数的值转换为等效的单精度浮点数。
ToSingle(UInt32)	将指定的 32 位无符号整数的值转换为等效的单精度浮点数。
ToSingle(String)	将数字的指定字符串表示形式转换为等效的单精度浮点数。
ToSingle(Single)	返回指定的单精度浮点数；不执行任何实际的转换。
ToSingle(Object)	将指定对象的值转换为单精度浮点数。
ToSingle(UInt16)	将指定的 16 位无符号整数的值转换为等效的单精度浮点数。
ToSingle(Int32)	将指定的 32 位带符号整数的值转换为等效的单精度浮点数。
ToSingle(Int16)	将指定的 16 位带符号整数的值转换为等效的单精度浮点数。
ToSingle(Double)	将指定的双精度浮点数的值转换为等效的单精度浮点数。
ToSingle(Decimal)	将指定的十进制数的值转换为等效的单精度浮点数。
ToSingle(DateTime)	调用此方法始终引发 InvalidCastException。
ToSingle(Char)	调用此方法始终引发 InvalidCastException。
ToSingle(Byte)	将指定的 8 位无符号整数的值转换为等效的单精度浮点数。
ToSingle(Boolean)	将指定的布尔值转换为等效的单精度浮点数。
ToSingle(Int64)	将指定的 64 位带符号整数的值转换为等效的单精度浮点数。

ToSingle(String, IFormatProvider)

Source:: Convert.cs

Source:: Convert.cs

Source:: Convert.cs

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单精度浮点数。

public:
 static float ToSingle(System::String ^ value, IFormatProvider ^ provider);

public static float ToSingle (string value, IFormatProvider provider);

public static float ToSingle (string? value, IFormatProvider? provider);

static member ToSingle : string * IFormatProvider -> single

Public Shared Function ToSingle (value As String, provider As IFormatProvider) As Single

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。

Single

与 value 中数字等效的单精度浮点数，如果 value 为 null，则为 0（零）。

例外

FormatException

value 不是一个具有有效格式的数字。

OverflowException

value 表示小于 Single.MinValue 或大于 Single.MaxValue 的数字。

示例

下面的示例在将数值字符串Single数组中的元素转换为值时，使用IFormatProvider表示 en-US 和 fr-FR 区域性的对象。

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      string[] values = { "123456789", "12345.6789", "12 345,6789",
                          "123,456.789", "123 456,789", "123,456,789.0123",
                          "123 456 789,0123", "1.235e12", "1.03221e-05",
                          Double.MaxValue.ToString() };
      CultureInfo[] cultures = { new CultureInfo("en-US"),
                                 new CultureInfo("fr-FR") };

      foreach (CultureInfo culture in cultures)
      {
         Console.WriteLine("String -> Single Conversion Using the {0} Culture",
                           culture.Name);
         foreach (string value in values)
         {
            Console.Write("{0,22}  ->  ", value);
            try {
               Console.WriteLine(Convert.ToSingle(value, culture));
            }
            catch (FormatException) {
               Console.WriteLine("FormatException");
            }
            catch (OverflowException) {
               Console.WriteLine("OverflowException");
            }
         }
         Console.WriteLine();
      }
   }
}
// The example displays the following output:
//    String -> Single Conversion Using the en-US Culture
//                 123456789  ->  1.234568E+08
//                12345.6789  ->  12345.68
//               12 345,6789  ->  FormatException
//               123,456.789  ->  123456.8
//               123 456,789  ->  FormatException
//          123,456,789.0123  ->  1.234568E+08
//          123 456 789,0123  ->  FormatException
//                  1.235e12  ->  1.235E+12
//               1.03221e-05  ->  1.03221E-05
//     1.79769313486232E+308  ->  Overflow
//
//    String -> Single Conversion Using the fr-FR Culture
//                 123456789  ->  1.234568E+08
//                12345.6789  ->  FormatException
//               12 345,6789  ->  12345.68
//               123,456.789  ->  FormatException
//               123 456,789  ->  123456.8
//          123,456,789.0123  ->  FormatException
//          123 456 789,0123  ->  1.234568E+08
//                  1.235e12  ->  FormatException
//               1.03221e-05  ->  FormatException
//     1.79769313486232E+308  ->  FormatException

open System
open System.Globalization

let values =
    [| "123456789"; "12345.6789"; "12 345,6789"
       "123,456.789"; "123 456,789"; "123,456,789.0123"
       "123 456 789,0123"; "1.235e12"; "1.03221e-05"
       string Double.MaxValue |]
let cultures =
    [| CultureInfo "en-US"; CultureInfo "fr-FR" |]

for culture in cultures do
    printfn $"String -> Single Conversion Using the {culture.Name} Culture"
    for value in values do
        printf $"{value,22}  ->  "
        try
            printfn $"{Convert.ToSingle(value, culture)}"
        with
        | :? FormatException ->
            printfn "FormatException"
        | :? OverflowException ->
            printfn "OverflowException"
    printfn ""
// The example displays the following output:
//    String -> Single Conversion Using the en-US Culture
//                 123456789  ->  1.234568E+08
//                12345.6789  ->  12345.68
//               12 345,6789  ->  FormatException
//               123,456.789  ->  123456.8
//               123 456,789  ->  FormatException
//          123,456,789.0123  ->  1.234568E+08
//          123 456 789,0123  ->  FormatException
//                  1.235e12  ->  1.235E+12
//               1.03221e-05  ->  1.03221E-05
//     1.79769313486232E+308  ->  Overflow
//
//    String -> Single Conversion Using the fr-FR Culture
//                 123456789  ->  1.234568E+08
//                12345.6789  ->  FormatException
//               12 345,6789  ->  12345.68
//               123,456.789  ->  FormatException
//               123 456,789  ->  123456.8
//          123,456,789.0123  ->  FormatException
//          123 456 789,0123  ->  1.234568E+08
//                  1.235e12  ->  FormatException
//               1.03221e-05  ->  FormatException
//     1.79769313486232E+308  ->  FormatException

Imports System.Globalization

Module Example
   Public Sub Main()
      Dim values() As String = { "123456789", "12345.6789", "12 345,6789", _
                                 "123,456.789", "123 456,789", "123,456,789.0123", _
                                 "123 456 789,0123", "1.235e12", "1.03221e-05", _
                                 Double.MaxValue.ToString() }
      Dim cultures() As CultureInfo = { New CultureInfo("en-US"), _
                                        New CultureInfo("fr-FR") } 

      For Each culture As CultureInfo In cultures
         Console.WriteLine("String -> Single Conversion Using the {0} Culture", _
                           culture.Name)
         For Each value As String In values
            Console.Write("{0,22}  ->  ", value)
            Try
               Console.WriteLine(Convert.ToSingle(value, culture))
            Catch e As FormatException
               Console.WriteLine("FormatException")
            CAtch e As OverflowException
               Console.WriteLine("Overflow")
            End Try   
         Next
         Console.WriteLine()
      Next                     
   End Sub
End Module
' The example displays the following output:
'    String -> Single Conversion Using the en-US Culture
'                 123456789  ->  1.234568E+08
'                12345.6789  ->  12345.68
'               12 345,6789  ->  FormatException
'               123,456.789  ->  123456.8
'               123 456,789  ->  FormatException
'          123,456,789.0123  ->  1.234568E+08
'          123 456 789,0123  ->  FormatException
'                  1.235e12  ->  1.235E+12
'               1.03221e-05  ->  1.03221E-05
'     1.79769313486232E+308  ->  Overflow
'    
'    String -> Single Conversion Using the fr-FR Culture
'                 123456789  ->  1.234568E+08
'                12345.6789  ->  FormatException
'               12 345,6789  ->  12345.68
'               123,456.789  ->  FormatException
'               123 456,789  ->  123456.8
'          123,456,789.0123  ->  FormatException
'          123 456 789,0123  ->  1.234568E+08
'                  1.235e12  ->  FormatException
'               1.03221e-05  ->  FormatException
'     1.79769313486232E+308  ->  FormatException

注解

返回值是在上value调用 Single.Parse 方法的结果。

provider 是获取 IFormatProvider NumberFormatInfo 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 provider 为 null， NumberFormatInfo 则使用当前区域性的。

如果希望在转换失败时不处理异常，可以改为调用 Single.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

ToSingle(SByte)

Source:: Convert.cs

Source:: Convert.cs

Source:: Convert.cs

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单精度浮点数。

public:
 static float ToSingle(System::SByte value);

[System.CLSCompliant(false)]
public static float ToSingle (sbyte value);

[<System.CLSCompliant(false)>]
static member ToSingle : sbyte -> single

Public Shared Function ToSingle (value As SByte) As Single

参数

value: SByte

要转换的 8 位带符号整数。

Single

一个与 value 等效的 8 位带符号整数。

属性: CLSCompliantAttribute

示例

以下示例将有符号字节数组中的每个元素转换为 Single 值。

sbyte[] numbers = { SByte.MinValue, -23, 0, 17, SByte.MaxValue };
float result;

foreach (sbyte number in numbers)
{
   result = Convert.ToSingle(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 Single value -128.
//    Converted the SByte value '-23' to the Single value -23.
//    Converted the SByte value '0' to the Single value 0.
//    Converted the SByte value '17' to the Single value 17.
//    Converted the SByte value '127' to the Single value 127.

let numbers = [| SByte.MinValue; -23y; 0y; 17y; SByte.MaxValue |]

for number in numbers do
    let result = Convert.ToSingle 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 Single value -128.
//    Converted the SByte value '-23' to the Single value -23.
//    Converted the SByte value '0' to the Single value 0.
//    Converted the SByte value '17' to the Single value 17.
//    Converted the SByte value '127' to the Single value 127.

Dim numbers() As SByte = { SByte.MinValue, -23, 0, 17, SByte.MaxValue }
Dim result As Single

For Each number As SByte In numbers
   result = Convert.ToSingle(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 Single value -128.
'    Converted the SByte value '-23' to the Single value -23.
'    Converted the SByte value '0' to the Single value 0.
'    Converted the SByte value '17' to the Single value 17.
'    Converted the SByte value '127' to the Single value 127.

适用于

ToSingle(Object, IFormatProvider)

Source:: Convert.cs

Source:: Convert.cs

Source:: Convert.cs

使用指定的区域性特定格式设置信息，将指定对象的值转换为单精度浮点数。

public:
 static float ToSingle(System::Object ^ value, IFormatProvider ^ provider);

public static float ToSingle (object value, IFormatProvider provider);

public static float ToSingle (object? value, IFormatProvider? provider);

static member ToSingle : obj * IFormatProvider -> single

Public Shared Function ToSingle (value As Object, provider As IFormatProvider) As Single

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。

Single

与 value 等效的单精度浮点数，如果 value 为 null，则为零。

例外

FormatException

value 的格式不正确。

InvalidCastException

value 不实现 IConvertible。

OverflowException

value 表示小于 Single.MinValue 或大于 Single.MaxValue 的数字。

示例

下面的示例定义一个实现 Temperature 接口的 IConvertible 类。该方法的 IConvertible.ToSingle 实现返回表示温度的私有 Single 变量的内部值。

using System;
using System.Globalization;

public class Temperature : IConvertible
{
   private float m_Temp;

   public Temperature(float temperature)
   {
      this.m_Temp = temperature;
   }

   public float Celsius
   {
      get { return this.m_Temp; }
   }

   public float Kelvin
   {
      get { return this.m_Temp + 273.15f; }
   }

   public float Fahrenheit
   {
      get { return (float) Math.Round(this.m_Temp * 9 / 5 + 32, 2); }
   }

   public override string ToString()
   {
      return m_Temp.ToString("N2") + " °C";
   }

   // IConvertible implementations.
   public TypeCode GetTypeCode()
   {
      return TypeCode.Object;
   }

   public bool ToBoolean(IFormatProvider provider)
   {
      if (m_Temp == 0)
         return false;
      else
         return true;
   }

   public byte ToByte(IFormatProvider provider)
   {
      if (m_Temp < Byte.MinValue || m_Temp > Byte.MaxValue)
         throw new OverflowException(String.Format("{0} is out of range of the Byte type.",
                                                   this.m_Temp));
      else
         return Convert.ToByte(this.m_Temp);
   }

   public char ToChar(IFormatProvider provider)
   {
      throw new InvalidCastException("Temperature to Char conversion is not supported.");
   }

   public DateTime ToDateTime(IFormatProvider provider)
   {
      throw new InvalidCastException("Temperature to DateTime conversion is not supported.");
   }

   public decimal ToDecimal(IFormatProvider provider)
   {
      return Convert.ToDecimal(this.m_Temp);
   }

   public double ToDouble(IFormatProvider provider)
   {
      return Convert.ToDouble(this.m_Temp);
   }

   public short ToInt16(IFormatProvider provider)
   {
      if (this.m_Temp < Int16.MinValue || this.m_Temp > Int16.MaxValue)
         throw new OverflowException(String.Format("{0} is out of range of the Int16 type.",
                                                   this.m_Temp));
      else
         return Convert.ToInt16(this.m_Temp);
   }

   public int ToInt32(IFormatProvider provider)
      {
      if (this.m_Temp < Int32.MinValue || this.m_Temp > Int32.MaxValue)
         throw new OverflowException(String.Format("{0} is out of range of the Int32 type.",
                                                   this.m_Temp));
      else
         return Convert.ToInt32(this.m_Temp);
   }

   public long ToInt64(IFormatProvider provider)
   {
      if (this.m_Temp < Int64.MinValue || this.m_Temp > Int64.MaxValue)
         throw new OverflowException(String.Format("{0} is out of range of the Int64 type.",
                                                   this.m_Temp));
      else
         return Convert.ToInt64(this.m_Temp);
   }

   public sbyte ToSByte(IFormatProvider provider)
   {
      if (this.m_Temp < SByte.MinValue || this.m_Temp > SByte.MaxValue)
         throw new OverflowException(String.Format("{0} is out of range of the SByte type.",
                                                   this.m_Temp));
      else
         return Convert.ToSByte(this.m_Temp);
   }

   public float ToSingle(IFormatProvider provider)
   {
      return this.m_Temp;
   }

   public string ToString(IFormatProvider provider)
   {
      return m_Temp.ToString("N2", provider) + " °C";
   }

   public object ToType(Type conversionType, IFormatProvider provider)
   {
      switch (Type.GetTypeCode(conversionType))
      {
         case TypeCode.Boolean:
            return this.ToBoolean(null);
         case TypeCode.Byte:
            return this.ToByte(null);
         case TypeCode.Char:
            return this.ToChar(null);
         case TypeCode.DateTime:
            return this.ToDateTime(null);
         case TypeCode.Decimal:
            return this.ToDecimal(null);
         case TypeCode.Double:
            return this.ToDouble(null);
         case TypeCode.Int16:
            return this.ToInt16(null);
         case TypeCode.Int32:
            return this.ToInt32(null);
         case TypeCode.Int64:
            return this.ToInt64(null);
         case TypeCode.Object:
            if (typeof(Temperature).Equals(conversionType))
               return this;
            else
               throw new InvalidCastException(String.Format("Conversion to a {0} is not supported.",
                                                            conversionType.Name));
         case TypeCode.SByte:
            return this.ToSByte(null);
         case TypeCode.Single:
            return this.ToSingle(null);
         case TypeCode.String:
            return this.ToString(provider);
         case TypeCode.UInt16:
            return this.ToUInt16(null);
         case TypeCode.UInt32:
            return this.ToUInt32(null);
         case TypeCode.UInt64:
            return this.ToUInt64(null);
         default:
            throw new InvalidCastException(String.Format("Conversion to {0} is not supported.", conversionType.Name));
      }
   }

   public ushort ToUInt16(IFormatProvider provider)
   {
      if (this.m_Temp < UInt16.MinValue || this.m_Temp > UInt16.MaxValue)
         throw new OverflowException(String.Format("{0} is out of range of the UInt16 type.",
                                                   this.m_Temp));
      else
         return Convert.ToUInt16(this.m_Temp);
   }

   public uint ToUInt32(IFormatProvider provider)
   {
      if (this.m_Temp < UInt32.MinValue || this.m_Temp > UInt32.MaxValue)
         throw new OverflowException(String.Format("{0} is out of range of the UInt32 type.",
                                                   this.m_Temp));
      else
         return Convert.ToUInt32(this.m_Temp);
   }

   public ulong ToUInt64(IFormatProvider provider)
   {
      if (this.m_Temp < UInt64.MinValue || this.m_Temp > UInt64.MaxValue)
         throw new OverflowException(String.Format("{0} is out of range of the UInt64 type.",
                                                   this.m_Temp));
      else
         return Convert.ToUInt64(this.m_Temp);
   }
}

open System

type Temperature(temperature: float32) =
    member _.Celsius =
        temperature

    member _.Kelvin =
        temperature + 273.15f

    member _.Fahrenheit =
        MathF.Round(temperature * 9f / 5f + 32f, 2)

    override _.ToString() =
        $"{temperature:N2} °C"

    // IConvertible implementations.
    interface IConvertible with

        member _.GetTypeCode() =
            TypeCode.Object

        member _.ToBoolean(provider: IFormatProvider) =
            temperature <> 0f

        member _.ToByte(provider: IFormatProvider) =
            if temperature < float32 Byte.MinValue || temperature > float32 Byte.MaxValue then
                raise (OverflowException $"{temperature} is out of range of the Byte type.")
            else
                Convert.ToByte temperature

        member _.ToChar(provider: IFormatProvider) =
            raise (InvalidCastException "Temperature to Char conversion is not supported.")

        member _.ToDateTime(provider: IFormatProvider) =
            raise (InvalidCastException "Temperature to DateTime conversion is not supported.")

        member _.ToDecimal(provider: IFormatProvider) =
            Convert.ToDecimal temperature

        member _.ToDouble(provider: IFormatProvider) =
            Convert.ToDouble temperature

        member _.ToInt16(provider: IFormatProvider) =
            if temperature < float32 Int16.MinValue || temperature > float32 Int16.MaxValue then
                raise (OverflowException $"{temperature} is out of range of the Int16 type.")
            else
                Convert.ToInt16 temperature

        member _.ToInt32(provider: IFormatProvider) =
            if temperature < float32 Int32.MinValue || temperature > float32 Int32.MaxValue then
                raise (OverflowException $"{temperature} is out of range of the Int32 type.")
            else
                Convert.ToInt32 temperature

        member _.ToInt64(provider: IFormatProvider) =
            if float32 temperature < float32 Int64.MinValue || temperature > float32 Int64.MaxValue then
                raise (OverflowException $"{temperature} is out of range of the Int64 type.")
            else
                Convert.ToInt64 temperature

        member _.ToSByte(provider: IFormatProvider) =
            if temperature < float32 SByte.MinValue || temperature > float32 SByte.MaxValue then
                raise (OverflowException $"{temperature} is out of range of the SByte type.")
            else
                Convert.ToSByte temperature

        member _.ToSingle(provider: IFormatProvider) =
            temperature

        override _.ToString(provider: IFormatProvider) =
            temperature.ToString("N2", provider) + " °C"

        member this.ToType(conversionType: Type, provider: IFormatProvider) =
            let this = this :> IConvertible
            match Type.GetTypeCode conversionType with
            | TypeCode.Boolean ->
                this.ToBoolean null
            | TypeCode.Byte ->
                this.ToByte null
            | TypeCode.Char ->
                this.ToChar null
            | TypeCode.DateTime ->
                this.ToDateTime null
            | TypeCode.Decimal ->
                this.ToDecimal null
            | TypeCode.Double ->
                this.ToDouble null
            | TypeCode.Int16 ->
                this.ToInt16 null
            | TypeCode.Int32 ->
                this.ToInt32 null
            | TypeCode.Int64 ->
                this.ToInt64 null
            | TypeCode.Object ->
                if typeof<Temperature>.Equals conversionType then
                    this
                else
                    raise (InvalidCastException $"Conversion to a {conversionType.Name} is not supported.")
            | TypeCode.SByte ->
                this.ToSByte null
            | TypeCode.Single ->
                this.ToSingle null
            | TypeCode.String ->
                this.ToString provider
            | TypeCode.UInt16 ->
                this.ToUInt16 null
            | TypeCode.UInt32 ->
                this.ToUInt32 null
            | TypeCode.UInt64 ->
                this.ToUInt64 null
            | _ ->
                    raise (InvalidCastException $"Conversion to {conversionType.Name} is not supported.")

        member _.ToUInt16(provider: IFormatProvider) =
            if temperature < float32 UInt16.MinValue || temperature > float32 UInt16.MaxValue then
                raise (OverflowException $"{temperature} is out of range of the UInt16 type.")
            else
                Convert.ToUInt16 temperature

        member _.ToUInt32(provider: IFormatProvider) =
            if temperature < float32 UInt32.MinValue || temperature > float32 UInt32.MaxValue then
                raise (OverflowException $"{temperature} is out of range of the UInt32 type.")
            else
                Convert.ToUInt32 temperature

        member _.ToUInt64(provider: IFormatProvider) =
            if temperature < float32 UInt64.MinValue || temperature > float32 UInt64.MaxValue then
                raise (OverflowException $"{temperature} is out of range of the UInt64 type.")
            else
                Convert.ToUInt64 temperature

Imports System.Globalization

Public Class Temperature : Implements IConvertible
   Private m_Temp As Single

   Public Sub New(temperature As Single)
      Me.m_Temp = temperature
   End Sub
   
   Public ReadOnly Property Celsius() As Single
      Get
         Return Me.m_Temp
      End Get   
   End Property
   
   Public ReadOnly Property Kelvin() As Single
      Get
         Return Me.m_Temp + 273.15F
      End Get
   End Property
   
   Public ReadOnly Property Fahrenheit() As Single
      Get
         Return CSng(Math.Round(Me.m_Temp * 9 / 5 + 32, 2))
      End Get      
   End Property
   
   Public Overrides Function ToString() As String
      Return m_Temp.ToString("N2") & " °C"
   End Function

   ' IConvertible implementations.
   Public Function GetTypeCode() As TypeCode _
                   Implements IConvertible.GetTypeCode
      Return TypeCode.Object
   End Function
   
   Public Function ToBoolean(provider As IFormatProvider) As Boolean _
                   Implements IConvertible.ToBoolean
      If m_Temp = 0 Then
         Return False
      Else
         Return True
      End If
   End Function 
   
   Public Function ToByte(provider As IFormatProvider) As Byte _
                   Implements IConvertible.ToByte
      If m_Temp < Byte.MinValue Or m_Temp > Byte.MaxValue Then
         Throw New OverflowException(String.Format("{0} is out of range of the Byte type.", _ 
                                                   Me.m_Temp)) 
      Else
         Return Convert.ToByte(Me.m_Temp)
      End If       
   End Function
   
   Public Function ToChar(provider As IFormatProvider) As Char _
                   Implements IConvertible.ToChar
      Throw New InvalidCastException("Temperature to Char conversion is not supported.")
   End Function 
   
   Public Function ToDateTime(provider As IFormatProvider) As Date _
                   Implements IConvertible.ToDateTime
      Throw New InvalidCastException("Temperature to DateTime conversion is not supported.")
   End Function
   
   Public Function ToDecimal(provider As IFormatProvider) As Decimal _
                   Implements IConvertible.ToDecimal
      Return Convert.ToDecimal(Me.m_Temp)
   End Function
   
   Public Function ToDouble(provider As IFormatProvider) As Double _
                   Implements IConvertible.ToDouble
      Return Convert.ToDouble(Me.m_Temp)
   End Function   
   
   Public Function ToInt16(provider As IFormatProvider) As Int16 _
                   Implements IConvertible.ToInt16
      If Me.m_Temp < Int16.MinValue Or Me.m_Temp > Int16.MaxValue Then
         Throw New OverflowException(String.Format("{0} is out of range of the Int16 type.", _
                                                   Me.m_Temp))
      Else
         Return Convert.ToInt16(Me.m_Temp)   
      End If
   End Function
   
   Public Function ToInt32(provider As IFormatProvider) As Int32 _
                   Implements IConvertible.ToInt32
      If Me.m_Temp < Int32.MinValue Or Me.m_Temp > Int32.MaxValue Then
         Throw New OverflowException(String.Format("{0} is out of range of the Int32 type.", _
                                                   Me.m_Temp))
      Else
         Return Convert.ToInt32(Me.m_Temp)
      End If      
   End Function
   
   Public Function ToInt64(provider As IFormatProvider) As Int64 _
                   Implements IConvertible.ToInt64
      If Me.m_Temp < Int64.MinValue Or Me.m_Temp > Int64.MaxValue Then
         Throw New OverflowException(String.Format("{0} is out of range of the Int64 type.", _
                                                   Me.m_Temp))
      Else
         Return Convert.ToInt64(Me.m_Temp)
      End If      
   End Function
   
   Public Function ToSByte(provider As IFormatProvider) As SByte _
                   Implements IConvertible.ToSByte
      If Me.m_Temp < SByte.MinValue Or Me.m_Temp > SByte.MaxValue Then
         Throw New OverflowException(String.Format("{0} is out of range of the SByte type.", _
                                                   Me.m_Temp))
      Else
         Return Convert.ToSByte(Me.m_Temp)
      End If      
   End Function

   Public Function ToSingle(provider As IFormatProvider) As Single _
                   Implements IConvertible.ToSingle
      Return Me.m_Temp
   End Function

   Public Overloads Function ToString(provider As IFormatProvider) As String _
                   Implements IConvertible.ToString
      Return m_Temp.ToString("N2", provider) & " °C"
   End Function
   
   Public Function ToType(conversionType As Type, provider As IFormatProvider) As Object _
                   Implements IConvertible.ToType
      Select Case Type.GetTypeCode(conversionType)
         Case TypeCode.Boolean 
            Return Me.ToBoolean(Nothing)
         Case TypeCode.Byte
            Return Me.ToByte(Nothing)
         Case TypeCode.Char
            Return Me.ToChar(Nothing)
         Case TypeCode.DateTime
            Return Me.ToDateTime(Nothing)
         Case TypeCode.Decimal
            Return Me.ToDecimal(Nothing)
         Case TypeCode.Double
            Return Me.ToDouble(Nothing)
         Case TypeCode.Int16
            Return Me.ToInt16(Nothing)
         Case TypeCode.Int32
            Return Me.ToInt32(Nothing)
         Case TypeCode.Int64
            Return Me.ToInt64(Nothing)
         Case TypeCode.Object
            If GetType(Temperature).Equals(conversionType) Then
               Return Me
            Else
               Throw New InvalidCastException(String.Format("Conversion to a {0} is not supported.", _
                                                            conversionType.Name))
            End If 
         Case TypeCode.SByte
            Return Me.ToSByte(Nothing)
         Case TypeCode.Single
            Return Me.ToSingle(Nothing)
         Case TypeCode.String
            Return Me.ToString(provider)
         Case TypeCode.UInt16
            Return Me.ToUInt16(Nothing)
         Case TypeCode.UInt32
            Return Me.ToUInt32(Nothing)
         Case TypeCode.UInt64
            Return Me.ToUInt64(Nothing)   
         Case Else
            Throw New InvalidCastException(String.Format("Conversion to {0} is not supported.", conversionType.Name))   
      End Select
   End Function
   
   Public Function ToUInt16(provider As IFormatProvider) As UInt16 _
                   Implements IConvertible.ToUInt16
      If Me.m_Temp < UInt16.MinValue Or Me.m_Temp > UInt16.MaxValue Then
         Throw New OverflowException(String.Format("{0} is out of range of the UInt16 type.", _
                                                   Me.m_Temp))
      Else
         Return Convert.ToUInt16(Me.m_Temp)
      End If   
   End Function

   Public Function ToUInt32(provider As IFormatProvider) As UInt32 _
                   Implements IConvertible.ToUInt32
      If Me.m_Temp < UInt32.MinValue Or Me.m_Temp > UInt32.MaxValue Then
         Throw New OverflowException(String.Format("{0} is out of range of the UInt32 type.", _
                                                   Me.m_Temp))
      Else
         Return Convert.ToUInt32(Me.m_Temp)
      End If   
   End Function
   
   Public Function ToUInt64(provider As IFormatProvider) As UInt64 _
                   Implements IConvertible.ToUInt64
      If Me.m_Temp < UInt64.MinValue Or Me.m_Temp > UInt64.MaxValue Then
         Throw New OverflowException(String.Format("{0} is out of range of the UInt64 type.", _
                                                   Me.m_Temp))
      Else
         Return Convert.ToUInt64(Me.m_temp)
      End If   
   End Function
End Class

下面的示例说明了对方法的 Convert.ToSingle(Object, IFormatProvider) 调用如何反过来调用 IConvertible.ToSingle 类的 Temperature 实现。

public class Example
{
   public static void Main()
   {
      Temperature cold = new Temperature(-40);
      Temperature freezing = new Temperature(0);
      Temperature boiling = new Temperature(100);

      Console.WriteLine(Convert.ToInt32(cold, null));
      Console.WriteLine(Convert.ToInt32(freezing, null));
      Console.WriteLine(Convert.ToDouble(boiling, null));
   }
}
// The example dosplays the following output:
//       -40
//       0
//       100

let cold = Temperature -40f
let freezing = Temperature 0f
let boiling = Temperature 100f

printfn $"{Convert.ToInt32(cold, null)}"
printfn $"{Convert.ToInt32(freezing, null)}"
printfn $"{Convert.ToDouble(boiling, null)}"
// The example dosplays the following output:
//       -40
//       0
//       100

Module Example
   Public Sub Main()
      Dim cold As New Temperature(-40)
      Dim freezing As New Temperature(0)
      Dim boiling As New Temperature(100)
      
      Console.WriteLine(Convert.ToInt32(cold, Nothing))
      Console.WriteLine(Convert.ToInt32(freezing, Nothing))
      Console.WriteLine(Convert.ToDouble(boiling, Nothing))
   End Sub
End Module
' The example displays the following output:
'       -40
'       0
'       100

注解

返回值是调用 IConvertible.ToSingle 的基础类型的 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 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

ToSingle(UInt64)

Source:: Convert.cs

Source:: Convert.cs

Source:: Convert.cs

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单精度浮点数。

public:
 static float ToSingle(System::UInt64 value);

[System.CLSCompliant(false)]
public static float ToSingle (ulong value);

[<System.CLSCompliant(false)>]
static member ToSingle : uint64 -> single

Public Shared Function ToSingle (value As ULong) As Single

参数

value: UInt64

要转换的 64 位无符号整数。

Single

一个等于 value 的单精度浮点数。

属性: CLSCompliantAttribute

示例

以下示例将无符号长整数数组中的每个元素转换为 Single 值。

ulong[] numbers = { UInt64.MinValue, 121, 12345, UInt64.MaxValue };
float result;

foreach (ulong number in numbers)
{
   result = Convert.ToSingle(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 UInt64 value '0' to the Single value 0.
//    Converted the UInt64 value '121' to the Single value 121.
//    Converted the UInt64 value '12345' to the Single value 12345.
//    Converted the UInt64 value '18446744073709551615' to the Single value 1.844674E+19.

let numbers = [| UInt64.MinValue; 121uL; 12345uL; UInt64.MaxValue |]

for number in numbers do
    let result = Convert.ToSingle number
    printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
// The example displays the following output:
//    Converted the UInt64 value '0' to the Single value 0.
//    Converted the UInt64 value '121' to the Single value 121.
//    Converted the UInt64 value '12345' to the Single value 12345.
//    Converted the UInt64 value '18446744073709551615' to the Single value 1.844674E+19.

Dim numbers() As ULong = { UInt64.MinValue, 121, 12345, UInt64.MaxValue }
Dim result As Single

For Each number As ULong In numbers
   result = Convert.ToSingle(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 UInt64 value '0' to the Single value 0.
'    Converted the UInt64 value '121' to the Single value 121.
'    Converted the UInt64 value '12345' to the Single value 12345.
'    Converted the UInt64 value '18446744073709551615' to the Single value 1.844674E+19.

适用于

ToSingle(UInt32)

Source:: Convert.cs

Source:: Convert.cs

Source:: Convert.cs

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单精度浮点数。

public:
 static float ToSingle(System::UInt32 value);

[System.CLSCompliant(false)]
public static float ToSingle (uint value);

[<System.CLSCompliant(false)>]
static member ToSingle : uint32 -> single

Public Shared Function ToSingle (value As UInteger) As Single

参数

value: UInt32

要转换的 32 位无符号整数。

Single

一个等于 value 的单精度浮点数。

属性: CLSCompliantAttribute

示例

以下示例将无符号整数数组中的每个元素转换为 Single 值。

uint[] numbers = { UInt32.MinValue, 121, 12345, UInt32.MaxValue };
float result;

foreach (uint number in numbers)
{
   result = Convert.ToSingle(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 UInt32 value '0' to the Single value 0.
//    Converted the UInt32 value '121' to the Single value 121.
//    Converted the UInt32 value '12345' to the Single value 12345.
//    Converted the UInt32 value '4294967295' to the Single value 4.294967E+09.

let numbers = [| UInt32.MinValue; 121u; 12345u; UInt32.MaxValue |]

for number in numbers do
    let result = Convert.ToSingle number
    printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
// The example displays the following output:
//    Converted the UInt32 value '0' to the Single value 0.
//    Converted the UInt32 value '121' to the Single value 121.
//    Converted the UInt32 value '12345' to the Single value 12345.
//    Converted the UInt32 value '4294967295' to the Single value 4.294967E+09.

   Dim numbers() As UInteger = { UInt32.MinValue, 121, 12345, UInt32.MaxValue }
   Dim result As Single

   For Each number As UInteger In numbers
      result = Convert.ToSingle(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 UInt32 value '0' to the Single value 0.
'    Converted the UInt32 value '121' to the Single value 121.
'    Converted the UInt32 value '12345' to the Single value 12345.
'    Converted the UInt32 value '4294967295' to the Single value 4.294967E+09.

适用于

ToSingle(String)

Source:: Convert.cs

Source:: Convert.cs

Source:: Convert.cs

将数字的指定字符串表示形式转换为等效的单精度浮点数。

public:
 static float ToSingle(System::String ^ value);

public static float ToSingle (string value);

public static float ToSingle (string? value);

static member ToSingle : string -> single

Public Shared Function ToSingle (value As String) As Single

参数

value: String

包含要转换的数字的字符串。

Single

与 value 中数字等效的单精度浮点数，如果 value 为 null，则为 0（零）。

例外

FormatException

value 不是一个具有有效格式的数字。

OverflowException

value 表示小于 Single.MinValue 或大于 Single.MaxValue 的数字。

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 Single 值。

string[] values= { "-1,035.77219", "1AFF", "1e-35", "1.63f",
                   "1,635,592,999,999,999,999,999,999", "-17.455",
                   "190.34001", "1.29e325"};
float result;

foreach (string value in values)
{
   try {
      result = Convert.ToSingle(value);
      Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.",
                        value.GetType().Name, value,
                        result.GetType().Name, result);
   }
   catch (FormatException) {
      Console.WriteLine("Unable to convert '{0}' to a Single.", value);
   }
   catch (OverflowException) {
      Console.WriteLine("'{0}' is outside the range of a Single.", value);
   }
}
// The example displays the following output:
//    Converted the String value '-1,035.77219' to the Single value -1035.772.
//    Unable to convert '1AFF' to a Single.
//    Converted the String value '1e-35' to the Single value 1E-35.
//    Unable to convert '1.63f' to a Single.
//    Converted the String value '1,635,592,999,999,999,999,999,999' to the Single value 1.635593E+24.
//    Converted the String value '-17.455' to the Single value -17.455.
//    Converted the String value '190.34001' to the Single value 190.34.
//    1.29e325' is outside the range of a Single.

let values =
    [| "-1,035.77219"; "1AFF"; "1e-35"; "1.63f"; "1,635,592,999,999,999,999,999,999"
       "-17.455"; "190.34001"; "1.29e325" |]

for value in values do
    try
        let result = Convert.ToSingle value
        printfn $"Converted the {value.GetType().Name} value {value} to the {result.GetType().Name} value {result}."
    with
    | :? FormatException ->
        printfn $"Unable to convert '{value}' to a Single."
    | :? OverflowException ->
        printfn $"'{value}' is outside the range of a Single."
// The example displays the following output:
//    Converted the String value '-1,035.77219' to the Single value -1035.772.
//    Unable to convert '1AFF' to a Single.
//    Converted the String value '1e-35' to the Single value 1E-35.
//    Unable to convert '1.63f' to a Single.
//    Converted the String value '1,635,592,999,999,999,999,999,999' to the Single value 1.635593E+24.
//    Converted the String value '-17.455' to the Single value -17.455.
//    Converted the String value '190.34001' to the Single value 190.34.
//    1.29e325' is outside the range of a Single.

Dim values() As String = { "-1,035.77219", "1AFF", "1e-35", "1.63f",
                           "1,635,592,999,999,999,999,999,999", "-17.455",
                           "190.34001", "1.29e325"}
Dim result As Single

For Each value As String In values
   Try
      result = Convert.ToSingle(value)
      Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.",
                        value.GetType().Name, value, _
                        result.GetType().Name, result)
   Catch e As FormatException
      Console.WriteLine("Unable to convert '{0}' to a Single.", value)
   Catch e As OverflowException
      Console.WriteLine("'{0}' is outside the range of a Single.", value)
   End Try
Next
' The example displays the following output:
'    Converted the String value '-1,035.77219' to the Single value -1035.772.
'    Unable to convert '1AFF' to a Single.
'    Converted the String value '1e-35' to the Single value 1E-35.
'    Unable to convert '1.63f' to a Single.
'    Converted the String value '1,635,592,999,999,999,999,999,999' to the Single value 1.635593E+24.
'    Converted the String value '-17.455' to the Single value -17.455.
'    Converted the String value '190.34001' to the Single value 190.34.
'    '1.29e325' is outside the range of a Single.

注解

ToSingle(String)使用方法等效于将传递给 valueSingle.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 Single.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

ToSingle(Single)

Source:: Convert.cs

Source:: Convert.cs

Source:: Convert.cs

返回指定的单精度浮点数；不执行任何实际的转换。

public:
 static float ToSingle(float value);

public static float ToSingle (float value);

static member ToSingle : single -> single

Public Shared Function ToSingle (value As Single) As Single

参数

value: Single

要返回的单精度浮点数。

Single

不经更改即返回 value。

另请参阅

Single

适用于

ToSingle(Object)

Source:: Convert.cs

Source:: Convert.cs

Source:: Convert.cs

将指定对象的值转换为单精度浮点数。

public:
 static float ToSingle(System::Object ^ value);

public static float ToSingle (object value);

public static float ToSingle (object? value);

static member ToSingle : obj -> single

Public Shared Function ToSingle (value As Object) As Single

参数

value: Object

用于实现 IConvertible 接口的对象，或为 null。

Single

与 value 等效的单精度浮点数，如果 value 为 null，则为零。

例外

FormatException

value 的格式不正确。

InvalidCastException

value 不实现 IConvertible 接口。

或

不支持该转换。

OverflowException

value 表示小于 Single.MinValue 或大于 Single.MaxValue 的数字。

示例

以下示例尝试将对象数组中的每个元素转换为 Single 值。

object[] values = { true, 'a', 123, 1.764e32, "9.78", "1e-02",
                    1.67e03, "A100", "1,033.67", DateTime.Now,
                    Decimal.MaxValue };
float result;

foreach (object value in values)
{
   try {
      result = Convert.ToSingle(value);
      Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.",
                        value.GetType().Name, value,
                        result.GetType().Name, result);
   }
   catch (FormatException) {
      Console.WriteLine("The {0} value {1} is not recognized as a valid Single value.",
                        value.GetType().Name, value);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Single type.",
                        value.GetType().Name, value);
   }
   catch (InvalidCastException) {
      Console.WriteLine("Conversion of the {0} value {1} to a Single is not supported.",
                        value.GetType().Name, value);
   }
}
// The example displays the following output:
//    Converted the Boolean value 'True' to the Single value 1.
//    Conversion of the Char value a to a Single is not supported.
//    Converted the Int32 value '123' to the Single value 123.
//    Converted the Double value '1.764E+32' to the Single value 1.764E+32.
//    Converted the String value '9.78' to the Single value 9.78.
//    Converted the String value '1e-02' to the Single value 0.01.
//    Converted the Double value '1670' to the Single value 1670.
//    The String value A100 is not recognized as a valid Single value.
//    Converted the String value '1,033.67' to the Single value 1033.67.
//    Conversion of the DateTime value 11/7/2008 08:02:35 AM to a Single is not supported.
//    Converted the Decimal value '79228162514264337593543950335' to the Single value 7.922816E+28.

let values: obj[] =
    [| true; 'a'; 123; 1.764e32; "9.78"; "1e-02"; 1.67e03; "A100"; "1,033.67"; DateTime.Now; Decimal.MaxValue |]

for value in values do
    try
        let result = Convert.ToSingle value            
        printfn $"Converted the {value.GetType().Name} value {value} to the {result.GetType().Name} value {result}."
    with
    | :? FormatException ->
        printfn $"The {value.GetType().Name} value {value} is not recognized as a valid Single value."
    | :? OverflowException ->
        printfn $"The {value.GetType().Name} value {value} is outside the range of the Single type."
    | :? InvalidCastException ->
        printfn $"Conversion of the {value.GetType().Name} value {value} to a Single is not supported."
// The example displays the following output:
//    Converted the Boolean value 'True' to the Single value 1.
//    Conversion of the Char value a to a Single is not supported.
//    Converted the Int32 value '123' to the Single value 123.
//    Converted the Double value '1.764E+32' to the Single value 1.764E+32.
//    Converted the String value '9.78' to the Single value 9.78.
//    Converted the String value '1e-02' to the Single value 0.01.
//    Converted the Double value '1670' to the Single value 1670.
//    The String value A100 is not recognized as a valid Single value.
//    Converted the String value '1,033.67' to the Single value 1033.67.
//    Conversion of the DateTime value 11/7/2008 08:02:35 AM to a Single is not supported.
//    Converted the Decimal value '79228162514264337593543950335' to the Single value 7.922816E+28.

Dim values() As Object = { True, "a"c, 123, 1.764e32, "9.78", "1e-02", _
                           1.67e03, "A100", "1,033.67", Date.Now, _
                           Decimal.MaxValue }
Dim result As Single

For Each value As Object In values
   Try
      result = Convert.ToSingle(value)
      Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.", _
                        value.GetType().Name, value, _
                        result.GetType().Name, result)

   Catch e As FormatException
      Console.WriteLine("The {0} value {1} is not recognized as a valid Single value.", _
                        value.GetType().Name, value)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Single type.", _
                        value.GetType().Name, value)

   Catch e As InvalidCastException
      Console.WriteLine("Conversion of the {0} value {1} to a Single is not supported.", _
                        value.GetType().Name, value)
   End Try
Next
' The example displays the following output:
'    Converted the Boolean value 'True' to the Single value 1.
'    Conversion of the Char value a to a Single is not supported.
'    Converted the Int32 value '123' to the Single value 123.
'    Converted the Double value '1.764E+32' to the Single value 1.764E+32.
'    Converted the String value '9.78' to the Single value 9.78.
'    Converted the String value '1e-02' to the Single value 0.01.
'    Converted the Double value '1670' to the Single value 1670.
'    The String value A100 is not recognized as a valid Single value.
'    Converted the String value '1,033.67' to the Single value 1033.67.
'    Conversion of the DateTime value 11/7/2008 07:56:24 AM to a Single is not supported.
'    Converted the Decimal value '79228162514264337593543950335' to the Single value 7.922816E+28.

注解

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

适用于

ToSingle(UInt16)

Source:: Convert.cs

Source:: Convert.cs

Source:: Convert.cs

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单精度浮点数。

public:
 static float ToSingle(System::UInt16 value);

[System.CLSCompliant(false)]
public static float ToSingle (ushort value);

[<System.CLSCompliant(false)>]
static member ToSingle : uint16 -> single

Public Shared Function ToSingle (value As UShort) As Single

参数

value: UInt16

要转换的 16 位无符号整数。

Single

一个等于 value 的单精度浮点数。

属性: CLSCompliantAttribute

示例

以下示例将无符号 16 位整数数组中的每个元素转换为 Single 值。

ushort[] numbers = { UInt16.MinValue, 121, 12345, UInt16.MaxValue };
float result;

foreach (ushort number in numbers)
{
   result = Convert.ToSingle(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 UInt16 value '0' to the Single value 0.
//    Converted the UInt16 value '121' to the Single value 121.
//    Converted the UInt16 value '12345' to the Single value 12345.
//    Converted the UInt16 value '65535' to the Single value 65535.

let numbers = [| UInt16.MinValue; 121us; 12345us; UInt16.MaxValue |]

for number in numbers do
    let result = Convert.ToSingle number
    printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
// The example displays the following output:
//    Converted the UInt16 value '0' to the Single value 0.
//    Converted the UInt16 value '121' to the Single value 121.
//    Converted the UInt16 value '12345' to the Single value 12345.
//    Converted the UInt16 value '65535' to the Single value 65535.

Dim numbers() As UShort = { UInt16.MinValue, 121, 12345, UInt16.MaxValue }
Dim result As Single

For Each number As UShort In numbers
   result = Convert.ToSingle(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 UInt16 value '0' to the Single value 0.
'    Converted the UInt16 value '121' to the Single value 121.
'    Converted the UInt16 value '12345' to the Single value 12345.
'    Converted the UInt16 value '65535' to the Single value 65535.

适用于

ToSingle(Int32)

Source:: Convert.cs

Source:: Convert.cs

Source:: Convert.cs

将指定的 32 位带符号整数的值转换为等效的单精度浮点数。

public:
 static float ToSingle(int value);

public static float ToSingle (int value);

static member ToSingle : int -> single

Public Shared Function ToSingle (value As Integer) As Single

参数

value: Int32

要转换的 32 位带符号整数。

Single

一个等于 value 的单精度浮点数。

示例

以下示例将整数数组中的每个元素转换为 Single 值。

int[] numbers = { Int32.MinValue, -1000, 0, 1000, Int32.MaxValue };
float result;

foreach (int number in numbers)
{
   result = Convert.ToSingle(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 Single value -2.147484E+09.
//    Converted the Int32 value '-1000' to the Single value -1000.
//    Converted the Int32 value '0' to the Single value 0.
//    Converted the Int32 value '1000' to the Single value 1000.
//    Converted the Int32 value '2147483647' to the Single value 2.147484E+09.

let numbers = 
    [| Int32.MinValue; -1000; 0; 1000; Int32.MaxValue |]

for number in numbers do
    let result = Convert.ToSingle number
    printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
// The example displays the following output:
//    Converted the Int32 value '-2147483648' to the Single value -2.147484E+09.
//    Converted the Int32 value '-1000' to the Single value -1000.
//    Converted the Int32 value '0' to the Single value 0.
//    Converted the Int32 value '1000' to the Single value 1000.
//    Converted the Int32 value '2147483647' to the Single value 2.147484E+09.

Dim numbers() As Integer = { Int32.MinValue, -1000, 0, 1000, Int32.MaxValue }
Dim result As Single

For Each number As Integer In numbers
   result = Convert.ToSingle(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 Single value -2.147484E+09.
'    Converted the Int32 value '-1000' to the Single value -1000.
'    Converted the Int32 value '0' to the Single value 0.
'    Converted the Int32 value '1000' to the Single value 1000.
'    Converted the Int32 value '2147483647' to the Single value 2.147484E+09.

适用于

ToSingle(Int16)

Source:: Convert.cs

Source:: Convert.cs

Source:: Convert.cs

将指定的 16 位带符号整数的值转换为等效的单精度浮点数。

public:
 static float ToSingle(short value);

public static float ToSingle (short value);

static member ToSingle : int16 -> single

Public Shared Function ToSingle (value As Short) As Single

参数

value: Int16

要转换的 16 位带符号整数。

Single

一个等于 value 的单精度浮点数。

示例

以下示例将 16 位整数数组中的每个元素转换为 Single 值。

short[] numbers = { Int16.MinValue, -1032, 0, 192, Int16.MaxValue };
float result;

foreach (short number in numbers)
{
   result = Convert.ToSingle(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 Int16 value '-32768' to the Single value -32768.
//    Converted the Int16 value '-1032' to the Single value -1032.
//    Converted the Int16 value '0' to the Single value 0.
//    Converted the Int16 value '192' to the Single value 192.
//    Converted the Int16 value '32767' to the Single value 32767.

let numbers = 
    [| Int16.MinValue; -1032s; 0s; 192s; Int16.MaxValue |]

for number in numbers do
    let result = Convert.ToSingle number
    printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
// The example displays the following output:
//    Converted the Int16 value '-32768' to the Single value -32768.
//    Converted the Int16 value '-1032' to the Single value -1032.
//    Converted the Int16 value '0' to the Single value 0.
//    Converted the Int16 value '192' to the Single value 192.
//    Converted the Int16 value '32767' to the Single value 32767.

Dim numbers() As Short = { Int16.MinValue, -1032, 0, 192, Int16.MaxValue }
Dim result As Single

For Each number As Short In numbers
   result = Convert.ToSingle(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 Single value -32768.
'    Converted the Int16 value '-1032' to the Single value -1032.
'    Converted the Int16 value '0' to the Single value 0.
'    Converted the Int16 value '192' to the Single value 192.
'    Converted the Int16 value '32767' to the Single value 32767.

适用于

ToSingle(Double)

Source:: Convert.cs

Source:: Convert.cs

Source:: Convert.cs

将指定的双精度浮点数的值转换为等效的单精度浮点数。

public:
 static float ToSingle(double value);

public static float ToSingle (double value);

static member ToSingle : double -> single

Public Shared Function ToSingle (value As Double) As Single

参数

value: Double

要转换的双精度浮点数。

Single

一个等于 value 的单精度浮点数。

使用“舍入为最接近的数字”规则对 value 进行舍入。例如，当舍入为两位小数时，值 2.345 变成 2.34，而值 2.355 变成 2.36。

示例

以下示例将值数组 Double 中的每个元素转换为 Single 值。

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

foreach (double value in values)
{
   result = Convert.ToSingle(value);
   Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.",
                     value.GetType().Name, value,
                     result.GetType().Name, result);
}
// The example displays the following output:
//    Converted the Double value '-1.79769313486232E+308' to the Single value -Infinity.
//    Converted the Double value '-13800000000' to the Single value -1.38E+10.
//    Converted the Double value '-1023.299' to the Single value -1023.299.
//    Converted the Double value '-12.98' to the Single value -12.98.
//    Converted the Double value '0' to the Single value 0.
//   Converted the Double value '9.113E-16' to the Single value 9.113E-16.
//    Converted the Double value '103.919' to the Single value 103.919.
//    Converted the Double value '17834.191' to the Single value 17834.19.
//    Converted the Double value '1.79769313486232E+308' to the Single value Infinity.

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
    let result = Convert.ToSingle value
    printfn $"Converted the {value.GetType().Name} value {value} to the {result.GetType().Name} value {result}."
// The example displays the following output:
//    Converted the Double value '-1.79769313486232E+308' to the Single value -Infinity.
//    Converted the Double value '-13800000000' to the Single value -1.38E+10.
//    Converted the Double value '-1023.299' to the Single value -1023.299.
//    Converted the Double value '-12.98' to the Single value -12.98.
//    Converted the Double value '0' to the Single value 0.
//   Converted the Double value '9.113E-16' to the Single value 9.113E-16.
//    Converted the Double value '103.919' to the Single value 103.919.
//    Converted the Double value '17834.191' to the Single value 17834.19.
//    Converted the Double value '1.79769313486232E+308' to the Single value Infinity.

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 Single

For Each value As Double In values
   result = Convert.ToSingle(value)
   Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.", _
                     value.GetType().Name, value, _
                     result.GetType().Name, result)
Next
' The example displays the following output:
'    Converted the Double value '-1.79769313486232E+308' to the Single value -Infinity.
'    Converted the Double value '-13800000000' to the Single value -1.38E+10.
'    Converted the Double value '-1023.299' to the Single value -1023.299.
'    Converted the Double value '-12.98' to the Single value -12.98.
'    Converted the Double value '0' to the Single value 0.
'    Converted the Double value '9.113E-16' to the Single value 9.113E-16.
'    Converted the Double value '103.919' to the Single value 103.919.
'    Converted the Double value '17834.191' to the Single value 17834.19.
'    Converted the Double value '1.79769313486232E+308' to the Single value Infinity.

另请参阅

Double
Round

适用于

ToSingle(Decimal)

Source:: Convert.cs

Source:: Convert.cs

Source:: Convert.cs

将指定的十进制数的值转换为等效的单精度浮点数。

public:
 static float ToSingle(System::Decimal value);

public static float ToSingle (decimal value);

static member ToSingle : decimal -> single

Public Shared Function ToSingle (value As Decimal) As Single

参数

value: Decimal

要转换的十进制数。

Single

一个等于 value 的单精度浮点数。

使用“舍入为最接近的数字”规则对 value 进行舍入。例如，当舍入为两位小数时，值 2.345 变成 2.34，而值 2.355 变成 2.36。

示例

以下示例将值数组 Decimal 中的每个元素转换为 Single 值。

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

foreach (var value in values)
{
   result = Convert.ToSingle(value);
   Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.",
                     value.GetType().Name, value,
                     result.GetType().Name, result);
}
// The example displays the following output:
//    Converted the Decimal value '-79228162514264337593543950335' to the Single value -7.9228163E+28.
//    Converted the Decimal value '-1034.23' to the Single value -1034.23.
//    Converted the Decimal value '-12' to the Single value -12.
//    Converted the Decimal value '0' to the Single value 0.
//    Converted the Decimal value '147' to the Single value 147.
//    Converted the Decimal value '199.55' to the Single value 199.55.
//    Converted the Decimal value '9214.16' to the Single value 9214.16.
//    Converted the Decimal value '79228162514264337593543950335' to the Single value 7.9228163E+28.

let values = 
    [| Decimal.MinValue; -1034.23m; -12m; 0m; 147m; 199.55m; 9214.16m; Decimal.MaxValue |]

for value in values do
    let result = Convert.ToSingle value
    printfn $"Converted the {value.GetType().Name} value {value} to the {result.GetType().Name} value {result}."
// The example displays the following output:
//    Converted the Decimal value '-79228162514264337593543950335' to the Single value -7.9228163E+28.
//    Converted the Decimal value '-1034.23' to the Single value -1034.23.
//    Converted the Decimal value '-12' to the Single value -12.
//    Converted the Decimal value '0' to the Single value 0.
//    Converted the Decimal value '147' to the Single value 147.
//    Converted the Decimal value '199.55' to the Single value 199.55.
//    Converted the Decimal value '9214.16' to the Single value 9214.16.
//    Converted the Decimal value '79228162514264337593543950335' to the Single value 7.9228163E+28.

Dim values() As Decimal = { Decimal.MinValue, -1034.23d, -12d, 0d, 147d, _
                            199.55d, 9214.16d, Decimal.MaxValue }
Dim result As Single

For Each value As Decimal In values
   result = Convert.ToSingle(value)
   Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.", _
                     value.GetType().Name, value, _
                     result.GetType().Name, result)
Next
' The example displays the following output:
'    Converted the Decimal value '-79228162514264337593543950335' to the Single value -7.922816E+28.
'    Converted the Decimal value '-1034.23' to the Single value -1034.23.
'    Converted the Decimal value '-12' to the Single value -12.
'    Converted the Decimal value '0' to the Single value 0.
'    Converted the Decimal value '147' to the Single value 147.
'    Converted the Decimal value '199.55' to the Single value 199.55.
'    Converted the Decimal value '9214.16' to the Single value 9214.16.
'    Converted the Decimal value '79228162514264337593543950335' to the Single value 7.922816E+28.

另请参阅

Round

适用于

ToSingle(DateTime)

Source:: Convert.cs

Source:: Convert.cs

Source:: Convert.cs

调用此方法始终引发 InvalidCastException。

public:
 static float ToSingle(DateTime value);

public static float ToSingle (DateTime value);

static member ToSingle : DateTime -> single

Public Shared Function ToSingle (value As DateTime) As Single

参数

value: DateTime

要转换的日期和时间值。

Single

不支持此转换。不返回任何值。

例外

InvalidCastException

不支持此转换。

适用于

ToSingle(Char)

Source:: Convert.cs

Source:: Convert.cs

Source:: Convert.cs

调用此方法始终引发 InvalidCastException。

public:
 static float ToSingle(char value);

public static float ToSingle (char value);

static member ToSingle : char -> single

Public Shared Function ToSingle (value As Char) As Single

参数

value: Char

要转换的 Unicode 字符。

Single

不支持此转换。不返回任何值。

例外

InvalidCastException

不支持此转换。

另请参阅

Char

适用于

ToSingle(Byte)

Source:: Convert.cs

Source:: Convert.cs

Source:: Convert.cs

将指定的 8 位无符号整数的值转换为等效的单精度浮点数。

public:
 static float ToSingle(System::Byte value);

public static float ToSingle (byte value);

static member ToSingle : byte -> single

Public Shared Function ToSingle (value As Byte) As Single

参数

value: Byte

要转换的 8 位无符号整数。

Single

一个等于 value 的单精度浮点数。

示例

以下示例将字节值数组中的每个元素转换为 Single 值。

byte[] numbers = { Byte.MinValue, 10, 100, Byte.MaxValue };
float result;

foreach (byte number in numbers)
{
   result = Convert.ToSingle(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 Byte value 0 to the Single value 0.
//       Converted the Byte value 10 to the Single value 10.
//       Converted the Byte value 100 to the Single value 100.
//       Converted the Byte value 255 to the Single value 255.

let numbers = [| Byte.MinValue; 10uy; 100uy; Byte.MaxValue |]

for number in numbers do
    let result = Convert.ToSingle number
    printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
// The example displays the following output:
//       Converted the Byte value 0 to the Single value 0.
//       Converted the Byte value 10 to the Single value 10.
//       Converted the Byte value 100 to the Single value 100.
//       Converted the Byte value 255 to the Single value 255.

Dim numbers() As Byte = { Byte.MinValue, 10, 100, Byte.MaxValue }
Dim result As Single

For Each number As Byte In numbers
   result = Convert.ToSingle(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 Byte value 0 to the Single value 0.
'       Converted the Byte value 10 to the Single value 10.
'       Converted the Byte value 100 to the Single value 100.
'       Converted the Byte value 255 to the Single value 255.

适用于

ToSingle(Boolean)

Source:: Convert.cs

Source:: Convert.cs

Source:: Convert.cs

将指定的布尔值转换为等效的单精度浮点数。

public:
 static float ToSingle(bool value);

public static float ToSingle (bool value);

static member ToSingle : bool -> single

Public Shared Function ToSingle (value As Boolean) As Single

参数

value: Boolean

要转换的布尔值。

Single

如果 value 为 true，则为数字 1；否则，为 0。

示例

以下示例将布尔值 true 和 false 转换为 Single 值。

bool[] flags = { true, false };
float result;

foreach (bool flag in flags)
{
   result = Convert.ToSingle(flag);
   Console.WriteLine("Converted {0} to {1}.", flag, result);
}
// The example displays the following output:
//       Converted True to 1.
//       Converted False to 0.

let flags = [| true; false |]

for flag in flags do
    let result = Convert.ToSingle flag
    printfn $"Converted {flag} to {result}."
// The example displays the following output:
//       Converted True to 1.
//       Converted False to 0.

Dim flags() As Boolean = { True, False }
Dim result As Single

For Each flag As Boolean In flags
   result = Convert.ToSingle(flag)
   Console.WriteLine("Converted {0} to {1}.", flag, result)
Next
' The example displays the following output:
'       Converted True to 1.
'       Converted False to 0.

适用于

ToSingle(Int64)

Source:: Convert.cs

Source:: Convert.cs

Source:: Convert.cs

将指定的 64 位带符号整数的值转换为等效的单精度浮点数。

public:
 static float ToSingle(long value);

public static float ToSingle (long value);

static member ToSingle : int64 -> single

Public Shared Function ToSingle (value As Long) As Single

参数

value: Int64

要转换的 64 位带符号整数。

Single

一个等于 value 的单精度浮点数。

示例

以下示例将长整数数组中的每个元素转换为 Single 值。

long[] numbers = { Int64.MinValue, -903, 0, 172, Int64.MaxValue};
float result;

foreach (long number in numbers)
{
   result = Convert.ToSingle(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 Int64 value '-9223372036854775808' to the Single value -9.223372E+18.
//    Converted the Int64 value '-903' to the Single value -903.
//    Converted the Int64 value '0' to the Single value 0.
//    Converted the Int64 value '172' to the Single value 172.
//    Converted the Int64 value '9223372036854775807' to the Single value 9.223372E+18.

let numbers = 
    [| Int64.MinValue; -903; 0; 172; Int64.MaxValue |]

for number in numbers do
    let result = Convert.ToSingle number
    printfn $"Converted the {number.GetType().Name} value {number} to the {result.GetType().Name} value {result}."
// The example displays the following output:
//    Converted the Int64 value '-9223372036854775808' to the Single value -9.223372E+18.
//    Converted the Int64 value '-903' to the Single value -903.
//    Converted the Int64 value '0' to the Single value 0.
//    Converted the Int64 value '172' to the Single value 172.
//    Converted the Int64 value '9223372036854775807' to the Single value 9.223372E+18.

      Dim numbers() As Long = { Int64.MinValue, -903, 0, 172, Int64.MaxValue}
      Dim result As Single

      For Each number As Long In numbers
         result = Convert.ToSingle(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 Int64 value '-9223372036854775808' to the Single value -9.223372E+18.
Converted the Int64 value '-903' to the Single value -903.
Converted the Int64 value '0' to the Single value 0.
Converted the Int64 value '172' to the Single value 172.
Converted the Int64 value '9223372036854775807' to the Single value 9.223372E+18.

      '    Converted the Int64 value '-9223372036854775808' to the Single value -9.223372E+18.
      '    Converted the Int64 value '-903' to the Single value -903.
      '    Converted the Int64 value '0' to the Single value 0.
      '    Converted the Int64 value '172' to the Single value 172.
      '    Converted the Int64 value '9223372036854775807' to the Single value 9.223372E+18.

适用于