Convert.ToDecimal 方法

定義

將指定的值轉換為十進位數字。Converts a specified value to a decimal number.

多載

ToDecimal(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十進位數字。Converts the specified string representation of a number to an equivalent decimal number, using the specified culture-specific formatting information.

ToDecimal(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相等的十進位數字。Converts the value of the specified object to an equivalent decimal number, using the specified culture-specific formatting information.

ToDecimal(UInt64)

將指定之 64 位元不帶正負號的整數值,轉換為相等的十進位數字。Converts the value of the specified 64-bit unsigned integer to an equivalent decimal number.

ToDecimal(UInt32)

將指定之 32 位元不帶正負號的整數值,轉換為相等的十進位數字。Converts the value of the specified 32-bit unsigned integer to an equivalent decimal number.

ToDecimal(UInt16)

將指定之 16 位元不帶正負號的整數值,轉換為相等的十進位數字。Converts the value of the specified 16-bit unsigned integer to an equivalent decimal number.

ToDecimal(String)

將指定之數字的字串表示,轉換為相等的十進位數字。Converts the specified string representation of a number to an equivalent decimal number.

ToDecimal(SByte)

將指定之 8 位元帶正負號的整數值,轉換為相等的十進位數字。Converts the value of the specified 8-bit signed integer to the equivalent decimal number.

ToDecimal(Object)

將指定之物件的值,轉換為相等的十進位數字。Converts the value of the specified object to an equivalent decimal number.

ToDecimal(Single)

將指定之單精確度浮點數的值,轉換為相等的十進位數字。Converts the value of the specified single-precision floating-point number to the equivalent decimal number.

ToDecimal(Int32)

將指定之 32 位元帶正負號的整數值,轉換為相等的十進位數字。Converts the value of the specified 32-bit signed integer to an equivalent decimal number.

ToDecimal(Boolean)

將指定的布林值轉換為相等的十進位數字。Converts the specified Boolean value to the equivalent decimal number.

ToDecimal(Byte)

將指定之 8 位元不帶正負號的整數值,轉換為相等的十進位數字。Converts the value of the specified 8-bit unsigned integer to the equivalent decimal number.

ToDecimal(Char)

呼叫這個方法一律會擲回 InvalidCastExceptionCalling this method always throws InvalidCastException.

ToDecimal(Int64)

將指定之 64 位元帶正負號的整數值,轉換為相等的十進位數字。Converts the value of the specified 64-bit signed integer to an equivalent decimal number.

ToDecimal(Decimal)

傳回指定的十進位數字,不執行實際的轉換。Returns the specified decimal number; no actual conversion is performed.

ToDecimal(Double)

將指定之雙精確度浮點數的值,轉換為相等的十進位數字。Converts the value of the specified double-precision floating-point number to an equivalent decimal number.

ToDecimal(Int16)

將指定之 16 位元帶正負號的整數值,轉換為相等的十進位數字。Converts the value of the specified 16-bit signed integer to an equivalent decimal number.

ToDecimal(DateTime)

呼叫這個方法一律會擲回 InvalidCastExceptionCalling this method always throws InvalidCastException.

ToDecimal(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十進位數字。Converts the specified string representation of a number to an equivalent decimal number, using the specified culture-specific formatting information.

public:
 static System::Decimal ToDecimal(System::String ^ value, IFormatProvider ^ provider);
public static decimal ToDecimal (string value, IFormatProvider provider);
static member ToDecimal : string * IFormatProvider -> decimal
Public Shared Function ToDecimal (value As String, provider As IFormatProvider) As Decimal

參數

value
String

字串,包含要轉換的數字。A string that contains a number to convert.

provider
IFormatProvider

物件,提供特定文化特性格式資訊。An object that supplies culture-specific formatting information.

傳回

value 中之數字相等的十進位數字;如果 valuenull,則為 0 (零)。A decimal number that is equivalent to the number in value, or 0 (zero) if value is null.

例外狀況

value 不是有效格式的數字。value is not a number in a valid format.

value 代表小於 MinValue 或大於 MaxValue 的數字。value represents a number that is less than MinValue or greater than MaxValue.

範例

下列範例會使用代表兩個不同文化特性的 NumberFormatInfo 物件,嘗試將字串陣列轉換成 Decimal 值。The following example attempts to convert an array of strings to Decimal values by using NumberFormatInfo objects that represent two different cultures.

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" };
      CultureInfo[] cultures = { new CultureInfo("en-US"),
                                 new CultureInfo("fr-FR") }; 

      foreach (CultureInfo culture in cultures)
      {
         Console.WriteLine("String -> Decimal Conversion Using the {0} Culture",
                           culture.Name);
         foreach (string value in values)
         {
            Console.Write("{0,20}  ->  ", value);
            try {
               Console.WriteLine(Convert.ToDecimal(value, culture));
            }
            catch (FormatException) {
               Console.WriteLine("FormatException");
            }
         }
         Console.WriteLine();
      }                     
   }
}
// The example displays the following output:
//       String -> Decimal Conversion Using the en-US Culture
//                  123456789  ->  123456789
//                 12345.6789  ->  12345.6789
//                12 345,6789  ->  FormatException
//                123,456.789  ->  123456.789
//                123 456,789  ->  FormatException
//           123,456,789.0123  ->  123456789.0123
//           123 456 789,0123  ->  FormatException
//       
//       String -> Decimal Conversion Using the fr-FR Culture
//                  123456789  ->  123456789
//                 12345.6789  ->  FormatException
//                12 345,6789  ->  12345.6789
//                123,456.789  ->  FormatException
//                123 456,789  ->  123456.789
//           123,456,789.0123  ->  FormatException
//           123 456 789,0123  ->  123456789.0123
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" }
      Dim cultures() As CultureInfo = { New CultureInfo("en-US"), _
                                        New CultureInfo("fr-FR") } 

      For Each culture As CultureInfo In cultures
         Console.WriteLine("String -> Decimal Conversion Using the {0} Culture", _
                           culture.Name)
         For Each value As String In values
            Console.Write("{0,20}  ->  ", value)
            Try
               Console.WriteLine(Convert.ToDecimal(value, culture))
            Catch e As FormatException
               Console.WriteLine("FormatException")
            End Try   
         Next
         Console.WriteLine()
      Next                     
   End Sub
End Module
' The example displays the following output:
'       String -> Decimal Conversion Using the en-US Culture
'                  123456789  ->  123456789
'                 12345.6789  ->  12345.6789
'                12 345,6789  ->  FormatException
'                123,456.789  ->  123456.789
'                123 456,789  ->  FormatException
'           123,456,789.0123  ->  123456789.0123
'           123 456 789,0123  ->  FormatException
'       
'       String -> Decimal Conversion Using the fr-FR Culture
'                  123456789  ->  123456789
'                 12345.6789  ->  FormatException
'                12 345,6789  ->  12345.6789
'                123,456.789  ->  FormatException
'                123 456,789  ->  123456.789
'           123,456,789.0123  ->  FormatException
'           123 456 789,0123  ->  123456789.0123

備註

傳回值是在 value上叫用 Decimal.Parse 方法的結果。The return value is the result of invoking the Decimal.Parse method on value.

provider 是取得 NumberFormatInfo 物件的 IFormatProvider 實例。provider is an IFormatProvider instance that obtains a NumberFormatInfo object. NumberFormatInfo 物件提供有關 value格式的特定文化特性資訊。The NumberFormatInfo object provides culture-specific information about the format of value. 如果 null``provider,則會使用目前文化特性的 NumberFormatInfoIf provider is null, the NumberFormatInfo for the current culture is used.

如果您不想在轉換失敗時處理例外狀況,您可以改為呼叫 Decimal.TryParse 方法。If you prefer not to handle an exception if the conversion fails, you can call the Decimal.TryParse method instead. 它會傳回 Boolean 值,指出轉換是否成功或失敗。It returns a Boolean value that indicates whether the conversion succeeded or failed.

ToDecimal(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相等的十進位數字。Converts the value of the specified object to an equivalent decimal number, using the specified culture-specific formatting information.

public:
 static System::Decimal ToDecimal(System::Object ^ value, IFormatProvider ^ provider);
public static decimal ToDecimal (object value, IFormatProvider provider);
static member ToDecimal : obj * IFormatProvider -> decimal
Public Shared Function ToDecimal (value As Object, provider As IFormatProvider) As Decimal

參數

value
Object

實作 IConvertible 介面的物件。An object that implements the IConvertible interface.

provider
IFormatProvider

物件,提供特定文化特性格式資訊。An object that supplies culture-specific formatting information.

傳回

value 相等的十進位數字;如果 valuenull,則為 0 (零)。A decimal number that is equivalent to value, or 0 (zero) if value is null.

例外狀況

value 的格式對於 Decimal 類型不正確。value is not in an appropriate format for a Decimal type.

value 未實作 IConvertible 介面。value does not implement the IConvertible interface.

-或--or- 不支援轉換。The conversion is not supported.

value 代表小於 MinValue 或大於 MaxValue 的數字。value represents a number that is less than MinValue or greater than MaxValue.

範例

下列範例定義一個實作 Temperature 介面的 IConvertible 類別。The following example defines a Temperature class that implements the IConvertible interface.

using System;
using System.Globalization;

public class Temperature : IConvertible
{
   private decimal m_Temp;

   public Temperature(decimal temperature)
   {
      this.m_Temp = temperature;
   }
   
   public decimal Celsius
   {
      get { return this.m_Temp; }   
   }
   
   public decimal Kelvin
   {
      get { return this.m_Temp + 273.15m; }    
   }
   
   public decimal Fahrenheit
   {
      get { return Math.Round((decimal) (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 Decimal.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 this.m_Temp;
   }
   
   public double ToDouble(IFormatProvider provider)
   {
      return Decimal.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 Decimal.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 Decimal.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 Decimal.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 Decimal.ToSByte(this.m_Temp);
   }

   public float ToSingle(IFormatProvider provider)
   {
      return Decimal.ToSingle(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 Decimal.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 Decimal.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 Decimal.ToUInt64(this.m_Temp);
   }
}
Imports System.Globalization

Public Class Temperature : Implements IConvertible
   Private m_Temp As Decimal

   Public Sub New(temperature As Decimal)
      Me.m_Temp = temperature
   End Sub
   
   Public ReadOnly Property Celsius() As Decimal
      Get
         Return Me.m_Temp
      End Get   
   End Property
   
   Public ReadOnly Property Kelvin() As Decimal
      Get
         Return Me.m_Temp + 273.15d   
      End Get
   End Property
   
   Public ReadOnly Property Fahrenheit() As Decimal
      Get
         Return Math.Round(CDec(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 Decimal.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 Me.m_Temp
   End Function
   
   Public Function ToDouble(provider As IFormatProvider) As Double _
                   Implements IConvertible.ToDouble
      Return Decimal.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 Decimal.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 Decimal.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 Decimal.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 Decimal.ToSByte(Me.m_Temp)
      End If      
   End Function

   Public Function ToSingle(provider As IFormatProvider) As Single _
                   Implements IConvertible.ToSingle
      Return Decimal.ToSingle(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 Decimal.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 Decimal.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 Decimal.ToUInt64(Me.m_temp)
      End If   
   End Function
End Class

下列範例顯示當 Temperature 物件當做參數傳遞至 ToDecimal(Object, IFormatProvider) 方法時,會呼叫 Temperature 類別的 IConvertible.ToDecimal 實作為執行轉換。The following example shows that when a Temperature object is passed as a parameter to the ToDecimal(Object, IFormatProvider) method, the IConvertible.ToDecimal implementation of the Temperature class is called to perform the conversion.

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.ToDecimal(cold, null));
      Console.WriteLine(Convert.ToDecimal(freezing, null));
      Console.WriteLine(Convert.ToDecimal(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.ToDecimal(cold, Nothing))
      Console.WriteLine(Convert.ToDecimal(freezing, Nothing))
      Console.WriteLine(Convert.ToDecimal(boiling, Nothing))
   End Sub
End Module
' The example displays the following output:
'       -40
'       0
'       100

備註

傳回值是叫用 value基礎類型之 IConvertible.ToDecimal 方法的結果。The return value is the result of invoking the IConvertible.ToDecimal method of the underlying type of value.

provider 可讓使用者指定有關 value內容的特定文化特性轉換資訊。provider enables the user to specify culture-specific conversion information about the contents of value. 基底類型會忽略 provider;不過,如果 value 是用來執行 IConvertible 介面的使用者定義型別,則可以使用參數。The base types ignore provider; however, the parameter may be used if value is a user-defined type that implements the IConvertible interface.

另請參閱

ToDecimal(UInt64)

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,轉換為相等的十進位數字。Converts the value of the specified 64-bit unsigned integer to an equivalent decimal number.

public:
 static System::Decimal ToDecimal(System::UInt64 value);
[System.CLSCompliant(false)]
public static decimal ToDecimal (ulong value);
static member ToDecimal : uint64 -> decimal
Public Shared Function ToDecimal (value As ULong) As Decimal

參數

value
UInt64

要轉換之 64 位元不帶正負號的整數。The 64-bit unsigned integer to convert.

傳回

十進位數字,其與 value 相等。A decimal number that is equivalent to value.

屬性

範例

下列範例會將不帶正負號的長整數陣列轉換成 Decimal 值。The following example converts an array of unsigned long integers to Decimal values.

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

foreach (ulong number in numbers)
{
   result = Convert.ToDecimal(number);
   Console.WriteLine("Converted the UInt64 value {0} to {1}.",
                     number, result);
}   
// The example displays the following output:
//    Converted the UInt64 value 0 to 0.
//    Converted the UInt64 value 121 to 121.
//    Converted the UInt64 value 12345 to 12345.
//    Converted the UInt64 value 18446744073709551615 to 18446744073709551615.
Dim numbers() As ULong = { UInt64.MinValue, 121, 12345, UInt64.MaxValue }
Dim result As Decimal

For Each number As ULong In numbers
   result = Convert.ToDecimal(number)
   Console.WriteLine("Converted the UInt64 value {0} to {1}.", _
                     number, result)
Next   
' The example displays the following output:
'    Converted the UInt64 value 0 to 0.
'    Converted the UInt64 value 121 to 121.
'    Converted the UInt64 value 12345 to 12345.
'    Converted the UInt64 value 18446744073709551615 to 18446744073709551615.

另請參閱

ToDecimal(UInt32)

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,轉換為相等的十進位數字。Converts the value of the specified 32-bit unsigned integer to an equivalent decimal number.

public:
 static System::Decimal ToDecimal(System::UInt32 value);
[System.CLSCompliant(false)]
public static decimal ToDecimal (uint value);
static member ToDecimal : uint32 -> decimal
Public Shared Function ToDecimal (value As UInteger) As Decimal

參數

value
UInt32

要轉換之 32 位元不帶正負號的整數。The 32-bit unsigned integer to convert.

傳回

十進位數字,其與 value 相等。A decimal number that is equivalent to value.

屬性

範例

下列範例會將不帶正負號整數的陣列轉換成 Decimal 值。The following example converts an array of unsigned integers to Decimal values.

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

foreach (uint number in numbers)
{
   result = Convert.ToDecimal(number);
   Console.WriteLine("Converted the UInt32 value {0} to {1}.",
                     number, result);
}   
// The example displays the following output:
//       Converted the UInt32 value 0 to 0.
//       Converted the UInt32 value 121 to 121.
//       Converted the UInt32 value 12345 to 12345.
//       Converted the UInt32 value 4294967295 to 4294967295.
Dim numbers() As UInteger = { UInt32.MinValue, 121, 12345, UInt32.MaxValue }
Dim result As Decimal

For Each number As UInteger In numbers
   result = Convert.ToDecimal(number)
   Console.WriteLine("Converted the UInt32 value {0} to {1}.", _
                     number, result)
Next   
' The example displays the following output:
'       Converted the UInt32 value 0 to 0.
'       Converted the UInt32 value 121 to 121.
'       Converted the UInt32 value 12345 to 12345.
'       Converted the UInt32 value 4294967295 to 4294967295.

另請參閱

ToDecimal(UInt16)

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,轉換為相等的十進位數字。Converts the value of the specified 16-bit unsigned integer to an equivalent decimal number.

public:
 static System::Decimal ToDecimal(System::UInt16 value);
[System.CLSCompliant(false)]
public static decimal ToDecimal (ushort value);
static member ToDecimal : uint16 -> decimal
Public Shared Function ToDecimal (value As UShort) As Decimal

參數

value
UInt16

要轉換之 16 位元不帶正負號的整數。The 16-bit unsigned integer to convert.

傳回

value 相等的十進位數字。The decimal number that is equivalent to value.

屬性

範例

下列範例會將16位不帶正負號整數的陣列轉換成 Decimal 值。The following example converts an array of 16-bit unsigned integers to Decimal values.

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

foreach (ushort number in numbers)
{
   result = Convert.ToDecimal(number);
   Console.WriteLine("Converted the UInt16 value {0} to {1}.",
                     number, result);
}   
// The example displays the following output:
//       Converted the UInt16 value 0 to 0.
//       Converted the UInt16 value 121 to 121.
//       Converted the UInt16 value 12345 to 12345.
//       Converted the UInt16 value 65535 to 65535.      
Dim numbers() As UShort = { UInt16.MinValue, 121, 12345, UInt16.MaxValue }
Dim result As Decimal

For Each number As UShort In numbers
   result = Convert.ToDecimal(number)
   Console.WriteLine("Converted the UInt16 value {0} to {1}.", _
                     number, result)
Next   
' The example displays the following output:
'       Converted the UInt16 value 0 to 0.
'       Converted the UInt16 value 121 to 121.
'       Converted the UInt16 value 12345 to 12345.
'       Converted the UInt16 value 65535 to 65535.      

另請參閱

ToDecimal(String)

將指定之數字的字串表示,轉換為相等的十進位數字。Converts the specified string representation of a number to an equivalent decimal number.

public:
 static System::Decimal ToDecimal(System::String ^ value);
public static decimal ToDecimal (string value);
static member ToDecimal : string -> decimal
Public Shared Function ToDecimal (value As String) As Decimal

參數

value
String

字串,包含要轉換的數字。A string that contains a number to convert.

傳回

value 中之數字相等的十進位數字;如果 valuenull,則為 0 (零)。A decimal number that is equivalent to the number in value, or 0 (zero) if value is null.

例外狀況

value 不是有效格式的數字。value is not a number in a valid format.

value 代表小於 MinValue 或大於 MaxValue 的數字。value represents a number that is less than MinValue or greater than MaxValue.

範例

下列範例說明如何使用 ToDecimalThe following example illustrates the use of ToDecimal. 它會嘗試將 String 轉換成 Decimal,並擲回可能在轉換期間發生的例外狀況。It attempts to convert a String to a Decimal, and throws the possible exceptions that may arise during the conversion.

public:
   void ConvertStringDecimal( String^ stringVal )
   {
      Decimal decimalVal = 0;

      try
      {
         decimalVal = System::Convert::ToDecimal( stringVal );
         System::Console::WriteLine( "The String as a decimal is {0}.",
         decimalVal );
      }
      catch ( System::OverflowException^ ) 
      {
         System::Console::WriteLine(
            "The conversion from String to decimal overflowed." );
      }
      catch ( System::FormatException^ ) 
      {
         System::Console::WriteLine(
            "The String is not formatted as a decimal." );
      }
      catch ( System::ArgumentNullException^ ) 
      {
         System::Console::WriteLine( "The String is 0." );
      }
      
      // Decimal to String conversion will not overflow.
      stringVal = System::Convert::ToString( decimalVal );
      System::Console::WriteLine(
         "The decimal as a String is {0}.", stringVal );
   }
public void ConvertStringDecimal(string stringVal) {
    decimal decimalVal = 0;
    
    try {
        decimalVal = System.Convert.ToDecimal(stringVal);
        System.Console.WriteLine(
            "The string as a decimal is {0}.", decimalVal);
    } 
    catch (System.OverflowException){
        System.Console.WriteLine(
            "The conversion from string to decimal overflowed.");
    }
    catch (System.FormatException) {
        System.Console.WriteLine(
            "The string is not formatted as a decimal.");
    }
    catch (System.ArgumentNullException) {
        System.Console.WriteLine(
            "The string is null.");
    }

    // Decimal to string conversion will not overflow.
    stringVal = System.Convert.ToString(decimalVal);
    System.Console.WriteLine(
        "The decimal as a string is {0}.", stringVal);
}	
Public Sub ConvertStringDecimal(ByVal stringVal As String)
    Dim decimalVal As Decimal = 0

    Try
        decimalVal = System.Convert.ToDecimal(stringVal)
        System.Console.WriteLine("The string as a decimal is {0}.", _
                                  decimalVal)
    Catch exception As System.OverflowException
        System.Console.WriteLine( _
            "Overflow in string-to-decimal conversion.")
    Catch exception As System.FormatException
        System.Console.WriteLine( _
            "The string is not formatted as a decimal.")
    Catch exception As System.ArgumentException
        System.Console.WriteLine("The string is null.")
    End Try

    ' Decimal to string conversion will not overflow.
    stringVal = System.Convert.ToString(decimalVal)
    System.Console.WriteLine("The decimal as a string is {0}.", _
                              stringVal)
End Sub

備註

使用 ToDecimal(String) 方法相當於將 value 傳遞至 Decimal.Parse(String) 方法。Using the ToDecimal(String) method is equivalent to passing value to the Decimal.Parse(String) method. value 是使用目前執行緒文化特性的格式化慣例來解譯。value is interpreted by using the formatting conventions of the current thread culture.

如果您不想在轉換失敗時處理例外狀況,您可以改為呼叫 Decimal.TryParse 方法。If you prefer not to handle an exception if the conversion fails, you can call the Decimal.TryParse method instead. 它會傳回 Boolean 值,指出轉換是否成功或失敗。It returns a Boolean value that indicates whether the conversion succeeded or failed.

ToDecimal(SByte)

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,轉換為相等的十進位數字。Converts the value of the specified 8-bit signed integer to the equivalent decimal number.

public:
 static System::Decimal ToDecimal(System::SByte value);
[System.CLSCompliant(false)]
public static decimal ToDecimal (sbyte value);
static member ToDecimal : sbyte -> decimal
Public Shared Function ToDecimal (value As SByte) As Decimal

參數

value
SByte

要轉換的 8 位元帶正負號的整數。The 8-bit signed integer to convert.

傳回

十進位數字,其與 value 相等。A decimal number that is equivalent to value.

屬性

範例

下列範例會將帶正負號的位元組陣列中的每個元素轉換成 Decimal 值。The following example converts each element in an array of signed bytes to a Decimal value.

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

foreach (sbyte number in numbers)
{
   result = Convert.ToDecimal(number);
   Console.WriteLine("Converted the SByte value {0} to {1}.", number, result);
}
//       Converted the SByte value -128 to -128.
//       Converted the SByte value -23 to -23.
//       Converted the SByte value 0 to 0.
//       Converted the SByte value 17 to 17.
//       Converted the SByte value 127 to 127.
Dim numbers() As SByte = { SByte.MinValue, -23, 0, 17, SByte.MaxValue }
Dim result As Decimal

For Each number As SByte In numbers
   result = Convert.ToDecimal(number)
   Console.WriteLine("Converted the SByte value {0} to {1}.", number, result)
Next
'       Converted the SByte value -128 to -128.
'       Converted the SByte value -23 to -23.
'       Converted the SByte value 0 to 0.
'       Converted the SByte value 17 to 17.
'       Converted the SByte value 127 to 127.

另請參閱

ToDecimal(Object)

將指定之物件的值,轉換為相等的十進位數字。Converts the value of the specified object to an equivalent decimal number.

public:
 static System::Decimal ToDecimal(System::Object ^ value);
public static decimal ToDecimal (object value);
static member ToDecimal : obj -> decimal
Public Shared Function ToDecimal (value As Object) As Decimal

參數

value
Object

實作 IConvertible 介面的物件,或是 nullAn object that implements the IConvertible interface, or null.

傳回

value 相等的十進位數字;如果 valuenull,則為 0 (零)。A decimal number that is equivalent to value, or 0 (zero) if value is null.

例外狀況

value 的格式對於 Decimal 類型不正確。value is not in an appropriate format for a Decimal type.

value 未實作 IConvertible 介面。value does not implement the IConvertible interface.

-或--or- 不支援轉換。The conversion is not supported.

value 代表小於 MinValue 或大於 MaxValue 的數字。value represents a number that is less than MinValue or greater than MaxValue.

範例

下列範例會嘗試將物件陣列中的每個元素轉換成 Decimal 值。The following example tries to convert each element in an object array to a Decimal value.

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

foreach (object value in values)
{
   try {
      result = Convert.ToDecimal(value);
      Console.WriteLine("Converted the {0} value {1} to {2}.",
                        value.GetType().Name, value, result);
   }                     
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is out of range of the Decimal type.",
                        value.GetType().Name, value);
   }                     
   catch (FormatException) {
      Console.WriteLine("The {0} value {1} is not recognized as a valid Decimal value.",
                        value.GetType().Name, value);
   }                     
   catch (InvalidCastException) {
      Console.WriteLine("Conversion of the {0} value {1} to a Decimal is not supported.",
                        value.GetType().Name, value);
   }                     
}
// The example displays the following output:
//    Converted the Boolean value True to 1.
//    Conversion of the Char value a to a Decimal is not supported.
//    Converted the Int32 value 123 to 123.
//    The Double value 1.764E+32 is out of range of the Decimal type.
//    Converted the String value 9.78 to 9.78.
//    The String value 1e-02 is not recognized as a valid Decimal value.
//    Converted the Double value 1670 to 1670.
//    The String value A100 is not recognized as a valid Decimal value.
//    Converted the String value 1,033.67 to 1033.67.
//    Conversion of the DateTime value 10/15/2008 05:40:42 PM to a Decimal is not supported.
//    The Double value 1.79769313486232E+308 is out of range of the Decimal type.      
Dim values() As Object = { True, "a"c, 123, 1.764e32, "9.78", "1e-02", _
                           1.67e03, "A100", "1,033.67", Date.Now, _
                           Double.MaxValue }   
Dim result As Decimal

For Each value As Object In values
   Try
      result = Convert.ToDecimal(value)
      Console.WriteLine("Converted the {0} value {1} to {2}.", _
                        value.GetType().Name, value, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is out of range of the Decimal type.", _
                        value.GetType().Name, value)
   Catch e As FormatException
      Console.WriteLine("The {0} value {1} is not recognized as a valid Decimal value.", _
                        value.GetType().Name, value)
   Catch e As InvalidCastException
      Console.WriteLine("Conversion of the {0} value {1} to a Decimal is not supported.", _
                        value.GetType().Name, value)
   End Try                     
Next
' The example displays the following output:
'    Converted the Boolean value True to 1.
'    Conversion of the Char value a to a Decimal is not supported.
'    Converted the Int32 value 123 to 123.
'    The Double value 1.764E+32 is out of range of the Decimal type.
'    Converted the String value 9.78 to 9.78.
'    The String value 1e-02 is not recognized as a valid Decimal value.
'    Converted the Double value 1670 to 1670.
'    The String value A100 is not recognized as a valid Decimal value.
'    Converted the String value 1,033.67 to 1033.67.
'    Conversion of the DateTime value 10/15/2008 05:40:42 PM to a Decimal is not supported.
'    The Double value 1.79769313486232E+308 is out of range of the Decimal type.      

備註

傳回值是叫用 value基礎類型之 IConvertible.ToDecimal 方法的結果。The return value is the result of invoking the IConvertible.ToDecimal method of the underlying type of value.

另請參閱

ToDecimal(Single)

將指定之單精確度浮點數的值,轉換為相等的十進位數字。Converts the value of the specified single-precision floating-point number to the equivalent decimal number.

public:
 static System::Decimal ToDecimal(float value);
public static decimal ToDecimal (float value);
static member ToDecimal : single -> decimal
Public Shared Function ToDecimal (value As Single) As Decimal

參數

value
Single

要轉換的單精確度浮點數。The single-precision floating-point number to convert.

傳回

十進位數字,其與 value 相等。A decimal number that is equivalent to value.

例外狀況

value 大於 MaxValue 或小於 MinValuevalue is greater than MaxValue or less than MinValue.

範例

下列範例會嘗試將 Single 值陣列中的每個元素轉換成 Decimal 值。The following example tries to convert each element in an array of Single values to a Decimal value.

float[] numbers = { Single.MinValue, -3e10f, -1093.54f, 0f, 1e-03f,
                    1034.23f, Single.MaxValue };
decimal result;

foreach (float number in numbers)
{
   try {
      result = Convert.ToDecimal(number);
      Console.WriteLine("Converted the Single value {0} to {1}.", number, result);
   }   
   catch (OverflowException) {
      Console.WriteLine("{0} is out of range of the Decimal type.", number);
   }
}                                  
// The example displays the following output:
//       -3.402823E+38 is out of range of the Decimal type.
//       Converted the Single value -3E+10 to -30000000000.
//       Converted the Single value -1093.54 to -1093.54.
//       Converted the Single value 0 to 0.
//       Converted the Single value 0.001 to 0.001.
//       Converted the Single value 1034.23 to 1034.23.
//       3.402823E+38 is out of range of the Decimal type.
Dim numbers() As Single = { Single.MinValue, -3e10, -1093.54, 0, 1e-03, _
                            1034.23, Single.MaxValue }
Dim result As Decimal

For Each number As Single In numbers
   Try
      result = Convert.ToDecimal(number)
      Console.WriteLine("Converted the Single value {0} to {1}.", number, result)
   Catch e As OverflowException
      Console.WriteLine("{0} is out of range of the Decimal type.", number)
   End Try
Next                                  
' The example displays the following output:
'       -3.402823E+38 is out of range of the Decimal type.
'       Converted the Single value -3E+10 to -30000000000.
'       Converted the Single value -1093.54 to -1093.54.
'       Converted the Single value 0 to 0.
'       Converted the Single value 0.001 to 0.001.
'       Converted the Single value 1034.23 to 1034.23.
'       3.402823E+38 is out of range of the Decimal type.

備註

這個方法所傳回的 Decimal 值最多包含七個有效位數。The Decimal value returned by this method contains a maximum of seven significant digits. 如果 value 參數包含超過七個有效位數,則會使用四捨五入到最接近的來四捨五入。If the value parameter contains more than seven significant digits, it is rounded using rounding to nearest. 下列範例說明 ToDecimal(Single) 方法如何使用最接近的舍入,傳回具有七個有效位數的 Decimal 值。The following example illustrates how the ToDecimal(Single) method uses rounding to nearest to return a Decimal value with seven significant digits.

Console.WriteLine(Convert.ToDecimal(1234567500.12F));  // Displays 1234568000
Console.WriteLine(Convert.ToDecimal(1234568500.12F));  // Displays 1234568000

Console.WriteLine(Convert.ToDecimal(10.980365F));      // Displays 10.98036 
Console.WriteLine(Convert.ToDecimal(10.980355F));      // Displays 10.98036
Console.WriteLine(Convert.ToDecimal(1234567500.12f))   ' Displays 1234568000
Console.WriteLine(Convert.ToDecimal(1234568500.12f))   ' Displays 1234568000

Console.WriteLine(Convert.ToDecimal(10.980365f))       ' Displays 10.98036 
Console.WriteLine(Convert.ToDecimal(10.980355f))       ' Displays 10.98036

另請參閱

ToDecimal(Int32)

將指定之 32 位元帶正負號的整數值,轉換為相等的十進位數字。Converts the value of the specified 32-bit signed integer to an equivalent decimal number.

public:
 static System::Decimal ToDecimal(int value);
public static decimal ToDecimal (int value);
static member ToDecimal : int -> decimal
Public Shared Function ToDecimal (value As Integer) As Decimal

參數

value
Int32

要轉換的 32 位元帶正負號的整數。The 32-bit signed integer to convert.

傳回

十進位數字,其與 value 相等。A decimal number that is equivalent to value.

範例

下列範例會將帶正負號的整數陣列轉換成 Decimal 值。The following example converts an array of signed integers to Decimal values.

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

foreach (int number in numbers)
{
   result = Convert.ToDecimal(number);
   Console.WriteLine("Converted the Int32 value {0} to the Decimal value {1}.",
                     number, result);
}
// The example displays the following output:
//    Converted the Int32 value -2147483648 to the Decimal value -2147483648.
//    Converted the Int32 value -1000 to the Decimal value -1000.
//    Converted the Int32 value 0 to the Decimal value 0.
//    Converted the Int32 value 1000 to the Decimal value 1000.
//    Converted the Int32 value 2147483647 to the Decimal value 2147483647.      
Dim numbers() As Integer = { Int32.MinValue, -1000, 0, 1000, Int32.MaxValue }
Dim result As Decimal

For Each number As Integer In numbers
   result = Convert.ToDecimal(number)
   Console.WriteLine("Converted the Int32 value {0} to the Decimal value {1}.", _
                     number, result)
Next
' The example displays the following output:
'    Converted the Int32 value -2147483648 to the Decimal value -2147483648.
'    Converted the Int32 value -1000 to the Decimal value -1000.
'    Converted the Int32 value 0 to the Decimal value 0.
'    Converted the Int32 value 1000 to the Decimal value 1000.
'    Converted the Int32 value 2147483647 to the Decimal value 2147483647.      

另請參閱

ToDecimal(Boolean)

將指定的布林值轉換為相等的十進位數字。Converts the specified Boolean value to the equivalent decimal number.

public:
 static System::Decimal ToDecimal(bool value);
public static decimal ToDecimal (bool value);
static member ToDecimal : bool -> decimal
Public Shared Function ToDecimal (value As Boolean) As Decimal

參數

value
Boolean

要轉換的布林值。The Boolean value to convert.

傳回

如果 valuetrue,則為數字 1,否則為 0。The number 1 if value is true; otherwise, 0.

範例

下列範例說明如何將 Boolean 轉換為 Decimal 值。The following example illustrates the conversion of Boolean to Decimal values.

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

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

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

另請參閱

ToDecimal(Byte)

將指定之 8 位元不帶正負號的整數值,轉換為相等的十進位數字。Converts the value of the specified 8-bit unsigned integer to the equivalent decimal number.

public:
 static System::Decimal ToDecimal(System::Byte value);
public static decimal ToDecimal (byte value);
static member ToDecimal : byte -> decimal
Public Shared Function ToDecimal (value As Byte) As Decimal

參數

value
Byte

要轉換之 8 位元不帶正負號的整數。The 8-bit unsigned integer to convert.

傳回

value 相等的十進位數字。The decimal number that is equivalent to value.

範例

下列範例會將 Byte 值轉換為 Decimal 值。The following example converts a Byte value to a Decimal value.

public:
   void ConvertByteDecimal( Byte byteVal )
   {
      Decimal decimalVal;
      
      // Byte to decimal conversion will not overflow.
      decimalVal = System::Convert::ToDecimal( byteVal );
      System::Console::WriteLine( "The Byte as a decimal is {0}.",
         decimalVal );
      
      // Decimal to Byte conversion can overflow.
      try
      {
         byteVal = System::Convert::ToByte( decimalVal );
         System::Console::WriteLine( "The Decimal as a Byte is {0}.",
         byteVal );
      }
      catch ( System::OverflowException^ ) 
      {
         System::Console::WriteLine(
            "The decimal value is too large for a Byte." );
      }
   }
public void ConvertByteDecimal(byte byteVal) {
    decimal decimalVal;

    // Byte to decimal conversion will not overflow.
    decimalVal = System.Convert.ToDecimal(byteVal);
    System.Console.WriteLine("The byte as a decimal is {0}.",
        decimalVal);

    // Decimal to byte conversion can overflow.
    try {
        byteVal = System.Convert.ToByte(decimalVal);
        System.Console.WriteLine("The Decimal as a byte is {0}.",
            byteVal);
    }
    catch (System.OverflowException) {
        System.Console.WriteLine(
            "The decimal value is too large for a byte.");
    }
}
Public Sub ConvertByteDecimal(ByVal byteVal As Byte)
    Dim decimalVal As Decimal

    ' Byte to decimal conversion will not overflow.
    decimalVal = System.Convert.ToDecimal(byteVal)
    System.Console.WriteLine("The byte as a decimal is {0}.", _
                              decimalVal)

    ' Decimal to byte conversion can overflow.
    Try
        byteVal = System.Convert.ToByte(decimalVal)
        System.Console.WriteLine("The Decimal as a byte is {0}.", _
                                  byteVal)
    Catch exception As System.OverflowException
        System.Console.WriteLine( _
            "Overflow in decimal-to-byte conversion.")
    End Try
End Sub

另請參閱

ToDecimal(Char)

呼叫這個方法一律會擲回 InvalidCastExceptionCalling this method always throws InvalidCastException.

public:
 static System::Decimal ToDecimal(char value);
public static decimal ToDecimal (char value);
static member ToDecimal : char -> decimal
Public Shared Function ToDecimal (value As Char) As Decimal

參數

value
Char

要轉換的 Unicode 字元。The Unicode character to convert.

傳回

不支援這個轉換。This conversion is not supported. 沒有傳回值。No value is returned.

例外狀況

不支援這個轉換。This conversion is not supported.

範例

下列範例會嘗試將 Char 值轉換成 Decimal,並在失敗時擲回 InvalidCastExceptionThe following example attempts to convert a Char value to Decimal, and throws InvalidCastException upon failure.

public:
   void ConvertCharDecimal( Char charVal )
   {
      Decimal decimalVal = 0;
      
      // Char to decimal conversion is not supported and will always
      // throw an InvalidCastException.
      try
      {
         decimalVal = System::Convert::ToDecimal( charVal );
      }
      catch ( System::InvalidCastException^ ) 
      {
         System::Console::WriteLine(
            "Char-to-Decimal conversion is not supported by the .NET Framework." );
      }
      
      //Decimal to char conversion is also not supported.
      try
      {
         charVal = System::Convert::ToChar( decimalVal );
      }
      catch ( System::InvalidCastException^ ) 
      {
         System::Console::WriteLine(
            "Decimal-to-Char conversion is not supported by the .NET Framework." );
      }
   }
public void ConvertCharDecimal(char charVal) {
    Decimal decimalVal = 0;
    
    // Char to decimal conversion is not supported and will always
    // throw an InvalidCastException.
    try {
        decimalVal = System.Convert.ToDecimal(charVal);
    } 
    catch (System.InvalidCastException) {
        System.Console.WriteLine(
            "Char-to-Decimal conversion is not supported " +
            "by the .NET Framework.");
    }

    //Decimal to char conversion is also not supported.
    try {
        charVal = System.Convert.ToChar(decimalVal);
    } 
    catch (System.InvalidCastException) {
        System.Console.WriteLine(
            "Decimal-to-Char conversion is not supported " +
            "by the .NET Framework.");
    }
}
Public Sub ConvertCharDecimal(ByVal charVal As Char)
    Dim decimalVal As [Decimal] = 0

    ' Char to decimal conversion is not supported and will always
    ' throw an InvalidCastException.
    Try
        decimalVal = System.Convert.ToDecimal(charVal)
    Catch exception As System.InvalidCastException
        System.Console.WriteLine( _
             "Char-to-Decimal conversion is not supported " + _
             "by the .NET Framework.")
    End Try

    'Decimal to char conversion is also not supported.
    Try
        charVal = System.Convert.ToChar(decimalVal)
    Catch exception As System.InvalidCastException
        System.Console.WriteLine( _
            "Decimal-to-Char conversion is not supported " + _
            "by the .NET Framework.")
    End Try
End Sub

另請參閱

ToDecimal(Int64)

將指定之 64 位元帶正負號的整數值,轉換為相等的十進位數字。Converts the value of the specified 64-bit signed integer to an equivalent decimal number.

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

參數

value
Int64

要轉換的 64 位元帶正負號的整數。The 64-bit signed integer to convert.

傳回

十進位數字,其與 value 相等。A decimal number that is equivalent to value.

範例

下列範例會將 Int64 值轉換為 Decimal 值。The following example converts an Int64 value to a Decimal value.

public:
   void ConvertLongDecimal( Int64 longVal )
   {
      Decimal decimalVal;
      
      // Long to decimal conversion cannot overflow.
      decimalVal = System::Convert::ToDecimal( longVal );
      System::Console::WriteLine( " {0} as a decimal is {1}",
         longVal, decimalVal );
      
      // Decimal to long conversion can overflow.
      try
      {
         longVal = System::Convert::ToInt64( decimalVal );
         System::Console::WriteLine( " {0} as a long is {1}",
         decimalVal, longVal );
      }
      catch ( System::OverflowException^ ) 
      {
         System::Console::WriteLine( "Overflow in decimal-to-long conversion." );
      }
   }
public void ConvertLongDecimal(long longVal) {

    decimal	decimalVal;
    
    // Long to decimal conversion cannot overflow.
    decimalVal = System.Convert.ToDecimal(longVal);
    System.Console.WriteLine("{0} as a decimal is {1}", 
            longVal, decimalVal);

    // Decimal to long conversion can overflow.
    try {
        longVal = System.Convert.ToInt64(decimalVal);
        System.Console.WriteLine("{0} as a long is {1}", 
            decimalVal, longVal);
    }
    catch (System.OverflowException) {
        System.Console.WriteLine(
            "Overflow in decimal-to-long conversion.");
    }
}
Public Sub ConvertLongDecimal(ByVal longVal As Long)

    Dim decimalVal As Decimal

    'Long to Decimal conversion cannot overflow.
    decimalVal = System.Convert.ToDecimal(longVal)
    System.Console.WriteLine("{0} as a Decimal is {1}", _
                              longVal, decimalVal)

    'Decimal to Long conversion can overflow.
    Try
        longVal = System.Convert.ToInt64(decimalVal)
        System.Console.WriteLine("{0} as a Long is {1}", _
                                  decimalVal, longVal)
    Catch exception As System.OverflowException
        System.Console.WriteLine( _
            "Overflow in decimal-to-long conversion.")
    End Try
End Sub

另請參閱

ToDecimal(Decimal)

傳回指定的十進位數字,不執行實際的轉換。Returns the specified decimal number; no actual conversion is performed.

public:
 static System::Decimal ToDecimal(System::Decimal value);
public static decimal ToDecimal (decimal value);
static member ToDecimal : decimal -> decimal
Public Shared Function ToDecimal (value As Decimal) As Decimal

參數

value
Decimal

十進位數字。A decimal number.

傳回

value 會原封不動地傳回。value is returned unchanged.

ToDecimal(Double)

將指定之雙精確度浮點數的值,轉換為相等的十進位數字。Converts the value of the specified double-precision floating-point number to an equivalent decimal number.

public:
 static System::Decimal ToDecimal(double value);
public static decimal ToDecimal (double value);
static member ToDecimal : double -> decimal
Public Shared Function ToDecimal (value As Double) As Decimal

參數

value
Double

要轉換的雙精確度浮點數。The double-precision floating-point number to convert.

傳回

十進位數字,其與 value 相等。A decimal number that is equivalent to value.

例外狀況

value 大於 MaxValue 或小於 MinValuevalue is greater than MaxValue or less than MinValue.

範例

下列範例會將 Double 值轉換為 Decimal 值。The following example converts a Double value to a Decimal value.

public:
   void ConvertDoubleDecimal( double doubleVal )
   {
      Decimal decimalVal;
      
      // Conversion from double to decimal cannot overflow.
      decimalVal = System::Convert::ToDecimal( doubleVal );
      System::Console::WriteLine( " {0} as a decimal is: {1}",
         doubleVal, decimalVal );
      
      // Decimal to double conversion can overflow.
      try
      {
         doubleVal = System::Convert::ToDouble( decimalVal );
         System::Console::WriteLine( " {0} as a double is: {1}",
         decimalVal, doubleVal );
      }
      catch ( System::OverflowException^ ) 
      {
         System::Console::WriteLine( "Overflow in decimal-to-double conversion." );
      }
   }
public void ConvertDoubleDecimal(decimal decimalVal){
    
    double doubleVal;
    
    // Decimal to double conversion cannot overflow.
 doubleVal = System.Convert.ToDouble(decimalVal);
    System.Console.WriteLine("{0} as a double is: {1}",
            decimalVal, doubleVal);

    // Conversion from double to decimal can overflow.
    try 
 {
       decimalVal = System.Convert.ToDecimal(doubleVal);
    System.Console.WriteLine ("{0} as a decimal is: {1}",
        doubleVal, decimalVal);
    } 
    catch (System.OverflowException) {
        System.Console.WriteLine(
            "Overflow in double-to-double conversion.");
    }
    

}
Public Sub ConvertDoubleDecimal(ByVal decimalVal As Decimal)

    Dim doubleVal As Double

    ' Decimal to Double conversion cannot overflow.
    doubleVal = System.Convert.ToDouble(decimalVal)
    System.Console.WriteLine("{0} as a Double is: {1}", _
                             decimalVal, doubleVal)
    
    ' Conversion from Double to Decimal can overflow.
    Try
       decimalVal = System.Convert.ToDecimal(doubleVal)
       System.Console.WriteLine("{0} as a Decimal is: {1}", _
                                doubleVal, decimalVal)
    Catch exception As System.OverflowException
        System.Console.WriteLine( _
            "Overflow in Double-to-Decimal conversion.")
    End Try

End Sub

備註

這個方法所傳回的 Decimal 值最多包含15個有效位數。The Decimal value returned by this method contains a maximum of 15 significant digits. 如果 value 參數包含超過15個有效位數,則會使用 [四捨五入至最接近] 將其四捨五入。If the value parameter contains more than 15 significant digits, it is rounded using rounding to nearest. 下列範例說明 Convert.ToDecimal(Double) 方法如何使用最接近的舍入,傳回具有15個有效位數的 Decimal 值。The following example illustrates how the Convert.ToDecimal(Double) method uses rounding to nearest to return a Decimal value with 15 significant digits.

Console.WriteLine(Convert.ToDecimal(123456789012345500.12D));  // Displays 123456789012346000
Console.WriteLine(Convert.ToDecimal(123456789012346500.12D));  // Displays 123456789012346000

Console.WriteLine(Convert.ToDecimal(10030.12345678905D));      // Displays 10030.123456789 
Console.WriteLine(Convert.ToDecimal(10030.12345678915D));      // Displays 10030.1234567892
Console.WriteLine(Convert.ToDecimal(123456789012345500.12R))   ' Displays 123456789012346000
Console.WriteLine(Convert.ToDecimal(123456789012346500.12R))   ' Displays 123456789012346000

Console.WriteLine(Convert.ToDecimal(10030.12345678905R))       ' Displays 10030.123456789 
Console.WriteLine(Convert.ToDecimal(10030.12345678915R))       ' Displays 10030.1234567892

另請參閱

ToDecimal(Int16)

將指定之 16 位元帶正負號的整數值,轉換為相等的十進位數字。Converts the value of the specified 16-bit signed integer to an equivalent decimal number.

public:
 static System::Decimal ToDecimal(short value);
public static decimal ToDecimal (short value);
static member ToDecimal : int16 -> decimal
Public Shared Function ToDecimal (value As Short) As Decimal

參數

value
Int16

要轉換的 16 位元帶正負號的整數。The 16-bit signed integer to convert.

傳回

十進位數字,其與 value 相等。A decimal number that is equivalent to value.

範例

下列範例會將16位帶正負號整數的陣列轉換成 Decimal 值。The following example converts an array of 16-bit signed integers to Decimal values.

short[] numbers = { Int16.MinValue, -1000, 0, 1000, Int16.MaxValue };
decimal result;

foreach (short number in numbers)
{
   result = Convert.ToDecimal(number);
   Console.WriteLine("Converted the Int16 value {0} to the Decimal value {1}.",
                     number, result);
}
// The example displays the following output:
//       Converted the Int16 value -32768 to the Decimal value -32768.
//       Converted the Int16 value -1000 to the Decimal value -1000.
//       Converted the Int16 value 0 to the Decimal value 0.
//       Converted the Int16 value 1000 to the Decimal value 1000.
//       Converted the Int16 value 32767 to the Decimal value 32767.
Dim numbers() As Short = { Int16.MinValue, -1000, 0, 1000, Int16.MaxValue }
Dim result As Decimal

For Each number As Short In numbers
   result = Convert.ToDecimal(number)
   Console.WriteLine("Converted the Int16 value {0} to the Decimal value {1}.", _
                     number, result)
Next
' The example displays the following output:
'       Converted the Int16 value -32768 to the Decimal value -32768.
'       Converted the Int16 value -1000 to the Decimal value -1000.
'       Converted the Int16 value 0 to the Decimal value 0.
'       Converted the Int16 value 1000 to the Decimal value 1000.
'       Converted the Int16 value 32767 to the Decimal value 32767.

另請參閱

ToDecimal(DateTime)

呼叫這個方法一律會擲回 InvalidCastExceptionCalling this method always throws InvalidCastException.

public:
 static System::Decimal ToDecimal(DateTime value);
public static decimal ToDecimal (DateTime value);
static member ToDecimal : DateTime -> decimal
Public Shared Function ToDecimal (value As DateTime) As Decimal

參數

value
DateTime

要轉換的日期和時間值。The date and time value to convert.

傳回

不支援這個轉換。This conversion is not supported. 沒有傳回值。No value is returned.

例外狀況

不支援這個轉換。This conversion is not supported.

適用於