Convert.ToSingle 方法

參考

定義

命名空間:: System

組件:: System.Runtime.Extensions.dll

組件:: System.Runtime.dll

組件:: mscorlib.dll

組件:: netstandard.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

將指定的值轉換為單精確度浮點數。

多載

ToSingle(String, IFormatProvider)	使用指定之特定文化特性格式資訊，將指定之數字的字串表示轉換為相等的單精確度浮點數。
ToSingle(SByte)	將指定之 8 位元帶正負號的整數值，轉換為相等的單精確度浮點數。
ToSingle(Object, IFormatProvider)	使用指定之特定文化特性格式資訊，將指定之物件的值轉換為單精確度浮點數。
ToSingle(UInt64)	將指定之 64 位元不帶正負號的整數值，轉換為相等的單精確度浮點數。
ToSingle(UInt32)	將指定之 32 位元不帶正負號的整數值，轉換為相等的單精確度浮點數。
ToSingle(String)	將指定之數字的字串表示，轉換為相等的單精確度浮點數。
ToSingle(Single)	傳回指定的單精確度浮點數，不執行實際的轉換。
ToSingle(Object)	將指定之物件的值，轉換為單精確度浮點數。
ToSingle(UInt16)	將指定之 16 位元不帶正負號的整數值，轉換為相等的單精確度浮點數。
ToSingle(Int32)	將指定之 32 位元帶正負號的整數值，轉換為相等的單精確度浮點數。
ToSingle(Int16)	將指定之 16 位元帶正負號的整數值，轉換為相等的單精確度浮點數。
ToSingle(Double)	將指定之雙精確度浮點數的值，轉換為相等的單精確度浮點數。
ToSingle(Decimal)	將指定之十進位數字的值，轉換為相等的單精確度浮點數。
ToSingle(DateTime)	呼叫這個方法一律會擲回 InvalidCastException。
ToSingle(Char)	呼叫這個方法一律會擲回 InvalidCastException。
ToSingle(Byte)	將指定之 8 位元不帶正負號的整數值，轉換為相等的單精確度浮點數。
ToSingle(Boolean)	將指定的布林值轉換為相等的單精確度浮點數。
ToSingle(Int64)	將指定之 64 位元帶正負號的整數值，轉換為相等的單精確度浮點數。

ToSingle(String, IFormatProvider)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

使用指定之特定文化特性格式資訊，將指定之數字的字串表示轉換為相等的單精確度浮點數。

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

參數

value: String

字串，包含要轉換的數字。

provider: IFormatProvider

物件，提供特定文化特性格式資訊。

傳回

Single

與 value 中之數字相等的單精確度浮點數；如果 value 為 null，則為 0 (零)。

例外狀況

FormatException

value 不是有效格式的數字。

OverflowException

value 代表小於 Single.MinValue 或大於 Single.MaxValue 的數位。

範例

下列範例會在將數值字串Single陣列中的項目轉換成值時，使用IFormatProvider代表 en-US 和 fr-FR 文化特性的物件。

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

備註

傳回值是在上value叫用 Single.Parse 方法的結果。

provider IFormatProvider是取得 NumberFormatInfo 對象的實例。物件 NumberFormatInfo 提供有關格式 value的文化特性特定資訊。如果為 providernull， NumberFormatInfo 則會使用目前文化特性的。

如果您不想在轉換失敗時處理例外狀況，您可以改為呼叫 Single.TryParse 方法。它會傳回值 Boolean ，指出轉換成功或失敗。

適用於

ToSingle(SByte)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

重要

此 API 不符合 CLS 規範。

將指定之 8 位元帶正負號的整數值，轉換為相等的單精確度浮點數。

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

參數

value: SByte

要轉換的 8 位元帶正負號的整數。

傳回

Single

與 value 相等的 8 位元帶正負號的整數。

屬性: CLSCompliantAttribute

範例

下列範例會將帶正負號位元組陣列中的每個項目轉換成 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.

適用於

ToSingle(Object, IFormatProvider)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

使用指定之特定文化特性格式資訊，將指定之物件的值轉換為單精確度浮點數。

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

參數

value: Object

實作 IConvertible 介面的物件。

provider: IFormatProvider

物件，提供特定文化特性格式資訊。

傳回

Single

與 value 相等的單精確度浮點數；如果 value 為 null，則為零。

例外狀況

FormatException

value 的格式不正確。

InvalidCastException

value 未實作 IConvertible。

OverflowException

value 代表小於 Single.MinValue 或大於 Single.MaxValue 的數位。

範例

下列範例定義一個實作 Temperature 介面的 IConvertible 類別。其方法的實作 IConvertible.ToSingle 會傳回代表 Single 溫度的私人變數內部值。

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

下列範例說明如何接著呼叫 Convert.ToSingle(Object, IFormatProvider) 方法，呼叫 IConvertible.ToSingle 類別的實作 Temperature 。

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

備註

傳回值是叫用 IConvertible.ToSingle 基礎類型 value之方法的結果。

provider 可讓使用者指定有關內容 value的文化特性特定轉換資訊。例如，如果 value 是 String 代表數位的， provider 可能會提供用來表示該數位之表示法的文化特性特定資訊。

基底類型會忽略 provider;不過，如果 value 是實作 IConvertible 介面的使用者定義型別，可以使用參數。

適用於

ToSingle(UInt64)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

重要

此 API 不符合 CLS 規範。

將指定之 64 位元不帶正負號的整數值，轉換為相等的單精確度浮點數。

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

參數

value: UInt64

要轉換之 64 位元不帶正負號的整數。

傳回

Single

單精確度浮點數，與 value 相等。

屬性: CLSCompliantAttribute

範例

下列範例會將不帶正負號長整數陣列中的每個元素轉換成 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.

適用於

ToSingle(UInt32)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

重要

此 API 不符合 CLS 規範。

將指定之 32 位元不帶正負號的整數值，轉換為相等的單精確度浮點數。

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

參數

value: UInt32

要轉換之 32 位元不帶正負號的整數。

傳回

Single

單精確度浮點數，與 value 相等。

屬性: CLSCompliantAttribute

範例

下列範例會將不帶正負號整數陣列中的每個項目轉換成 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.

適用於

ToSingle(String)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

將指定之數字的字串表示，轉換為相等的單精確度浮點數。

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

參數

value: String

字串，包含要轉換的數字。

傳回

Single

與 value 中之數字相等的單精確度浮點數；如果 value 為 null，則為 0 (零)。

例外狀況

FormatException

value 不是有效格式的數字。

OverflowException

value 代表小於 Single.MinValue 或大於 Single.MaxValue 的數位。

範例

下列範例會嘗試將數值字串陣列中的每個項目轉換成 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.

備註

ToSingle(String)使用方法相當於傳遞value至 Single.Parse(String) 方法。 value 會使用目前文化特性的格式化慣例來解譯。

如果您不想在轉換失敗時處理例外狀況，您可以改為呼叫 Single.TryParse 方法。它會傳回值 Boolean ，指出轉換成功或失敗。

適用於

ToSingle(Single)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

傳回指定的單精確度浮點數，不執行實際的轉換。

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

參數

value: Single

要傳回的單精確度浮點數。

傳回

Single

value 會原封不動地傳回。

另請參閱

Single

適用於

ToSingle(Object)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

將指定之物件的值，轉換為單精確度浮點數。

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

參數

value: Object

實作 IConvertible 介面的物件，或是 null。

傳回

Single

與 value 相等的單精確度浮點數；如果 value 為 null，則為零。

例外狀況

FormatException

value 的格式不正確。

InvalidCastException

value 未實作 IConvertible 介面。

-或-

不支援轉換。

OverflowException

value 代表小於 Single.MinValue 或大於 Single.MaxValue 的數位。

範例

下列範例會嘗試將物件陣列中的每個項目轉換成 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.

備註

傳回值是叫 IConvertible.ToSingle 用基礎型 value別之方法的結果。

適用於

ToSingle(UInt16)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

重要

此 API 不符合 CLS 規範。

將指定之 16 位元不帶正負號的整數值，轉換為相等的單精確度浮點數。

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

參數

value: UInt16

要轉換之 16 位元不帶正負號的整數。

傳回

Single

單精確度浮點數，與 value 相等。

屬性: CLSCompliantAttribute

範例

下列範例會將不帶正負號 16 位整數 Single 陣列中的每個項目轉換成值。

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.

適用於

ToSingle(Int32)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

將指定之 32 位元帶正負號的整數值，轉換為相等的單精確度浮點數。

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

參數

value: Int32

要轉換的 32 位元帶正負號的整數。

傳回

Single

單精確度浮點數，與 value 相等。

範例

下列範例會將整數陣列 Single 中的每個項目轉換成值。

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.

適用於

ToSingle(Int16)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

將指定之 16 位元帶正負號的整數值，轉換為相等的單精確度浮點數。

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

參數

value: Int16

要轉換的 16 位元帶正負號的整數。

傳回

Single

單精確度浮點數，與 value 相等。

範例

下列範例會將16位整數 Single 陣列中的每個項目轉換成值。

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.

適用於

ToSingle(Double)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

將指定之雙精確度浮點數的值，轉換為相等的單精確度浮點數。

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

參數

value: Double

要轉換的雙精確度浮點數。

傳回

Single

單精確度浮點數，與 value 相等。

value 會四捨五入為最接近的數字。例如，在四捨五入為兩個小數位數時，值 2.345 會變成 2.34，而值 2.355 會變成 2.36。

範例

下列範例會將值Single陣列Double中的每個項目轉換成值。

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.

另請參閱

Double
Round

適用於

ToSingle(Decimal)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

將指定之十進位數字的值，轉換為相等的單精確度浮點數。

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

參數

value: Decimal

要轉換的十進位數字。

傳回

Single

單精確度浮點數，與 value 相等。

value 會四捨五入為最接近的數字。例如，在四捨五入為兩個小數位數時，值 2.345 會變成 2.34，而值 2.355 會變成 2.36。

範例

下列範例會將值Single陣列Decimal中的每個項目轉換成值。

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.

另請參閱

Round

適用於

ToSingle(DateTime)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫這個方法一律會擲回 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

參數

value: DateTime

要轉換的日期和時間值。

傳回

Single

不支援此轉換。沒有傳回值。

例外狀況

InvalidCastException

不支援此轉換。

適用於

ToSingle(Char)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫這個方法一律會擲回 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

參數

value: Char

要轉換的 Unicode 字元。

傳回

Single

不支援此轉換。沒有傳回值。

例外狀況

InvalidCastException

不支援此轉換。

另請參閱

Char

適用於

ToSingle(Byte)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

將指定之 8 位元不帶正負號的整數值，轉換為相等的單精確度浮點數。

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

參數

value: Byte

要轉換之 8 位元不帶正負號的整數。

傳回

Single

單精確度浮點數，與 value 相等。

範例

下列範例會將位元組值 Single 陣列中的每個項目轉換成值。

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.

適用於

ToSingle(Boolean)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

將指定的布林值轉換為相等的單精確度浮點數。

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

參數

value: Boolean

要轉換的布林值。

傳回

Single

如果 value 為 true，則為數字 1，否則為 0。

範例

下列範例會將布爾值 true 和 false 轉換為 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.

適用於

ToSingle(Int64)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

將指定之 64 位元帶正負號的整數值，轉換為相等的單精確度浮點數。

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

參數

value: Int64

要轉換的 64 位元帶正負號的整數。

傳回

Single

單精確度浮點數，與 value 相等。

範例

下列範例會將長整數 Single 數位中的每個項目轉換成值。

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.

適用於

共用方式為

Convert.ToSingle 方法

定義

多載

ToSingle(String, IFormatProvider)

參數

傳回

例外狀況

範例

備註

適用於

ToSingle(SByte)

參數

傳回

範例

適用於

ToSingle(Object, IFormatProvider)

參數

傳回

例外狀況

範例

備註

適用於

ToSingle(UInt64)

參數

傳回

範例

適用於

ToSingle(UInt32)

參數

傳回

範例

適用於

ToSingle(String)

參數

傳回

例外狀況

範例

備註

適用於

ToSingle(Single)

參數

傳回

另請參閱

適用於

ToSingle(Object)

參數

傳回

例外狀況

範例

備註

適用於

ToSingle(UInt16)

參數

傳回

範例

適用於

ToSingle(Int32)

參數

傳回

範例

適用於

ToSingle(Int16)

參數

傳回

範例

適用於

ToSingle(Double)

參數

傳回

範例

另請參閱

適用於

ToSingle(Decimal)

參數

傳回

範例

另請參閱

適用於

ToSingle(DateTime)