共用方式為


Convert.ToDecimal Method (String, IFormatProvider)

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Converts the specified String representation of a number to an equivalent Decimal number using the specified culture-specific formatting information.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

Syntax

'Declaration
Public Shared Function ToDecimal ( _
    value As String, _
    provider As IFormatProvider _
) As Decimal
public static decimal ToDecimal(
    string value,
    IFormatProvider provider
)

Parameters

Return Value

Type: System.Decimal
A Decimal number equivalent to the value of value.
-or-
Zero if value is nulla null reference (Nothing in Visual Basic).

Exceptions

Exception Condition
FormatException

value is not a number in a valid format.

OverflowException

value represents a number less than MinValue or greater than MaxValue.

Remarks

The return value is the result of invoking the Decimal.Parse method on value.

provider is an IFormatProvider instance that obtains a NumberFormatInfo object. The NumberFormatInfo object provides culture-specific information about the format of value. If provider is nulla null reference (Nothing in Visual Basic), the NumberFormatInfo for the current culture is used.

If you prefer not to handle an exception if the conversion fails, you can call the Decimal.TryParse method instead. It returns a Boolean value that indicates whether the conversion succeeded or failed.

Examples

The following code example converts String representations of Decimal values with the ToDecimal method, using an IFormatProvider object.

' Example of the Convert.ToDecimal( String ) and 
' Convert.ToDecimal( String, IFormatProvider ) methods.
Imports System.Globalization

Module Example

   Dim formatter As String = "{0,-22}{1,-20}{2}"

   ' Get the exception type name; remove the namespace prefix.
   Function GetExceptionType(ByVal ex As Exception) As String

      Dim exceptionType As String = ex.GetType().ToString()
      GetExceptionType = exceptionType.Substring( _
          exceptionType.LastIndexOf("."c) + 1)
   End Function

   Sub ConvertToDecimal(ByVal outputBlock As System.Windows.Controls.TextBlock, ByVal numericStr As String, _
       ByVal provider As IFormatProvider)

      Dim defaultValue As Object
      Dim providerValue As Object

      ' Convert numericStr to Decimal without a format provider.
      Try
         defaultValue = Convert.ToDecimal(numericStr)
      Catch ex As Exception
         defaultValue = GetExceptionType(ex)
      End Try

      ' Convert numericStr to Decimal with a format provider.
      Try
         providerValue = Convert.ToDecimal(numericStr, provider)
      Catch ex As Exception
         providerValue = GetExceptionType(ex)
      End Try

      outputBlock.Text &= String.Format(formatter, numericStr, _
          defaultValue, providerValue) & vbCrLf
   End Sub

   Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)

      ' Create a NumberFormatInfo object and set several of its
      ' properties that apply to numbers.
      Dim provider As NumberFormatInfo = New NumberFormatInfo()

      provider.NumberDecimalSeparator = ","
      provider.NumberGroupSeparator = "."
      provider.NumberGroupSizes = New Integer() {3}

      outputBlock.Text &= String.Format("This example of" & vbCrLf & _
          "  Convert.ToDecimal( String ) and " & vbCrLf & _
          "  Convert.ToDecimal( String, IFormatProvider ) " & _
          vbCrLf & "generates the " & _
          "following output when run in the [{0}] culture.", _
          CultureInfo.CurrentCulture.Name) & vbCrLf
      outputBlock.Text &= String.Format(vbCrLf & _
          "Several strings are converted to Decimal values, " & _
          "using " & vbCrLf & "default formatting " & _
          "and a NumberFormatInfo object." & vbCrLf) & vbCrLf
      outputBlock.Text &= String.Format(formatter, "String to convert", _
          "Default/exception", "Provider/exception") & vbCrLf
      outputBlock.Text &= String.Format(formatter, "-----------------", _
          "-----------------", "------------------") & vbCrLf

      ' Convert strings, with and without an IFormatProvider.
      ConvertToDecimal(outputBlock, "123456789", provider)
      ConvertToDecimal(outputBlock, "12345.6789", provider)
      ConvertToDecimal(outputBlock, "12345,6789", provider)
      ConvertToDecimal(outputBlock, "123,456.789", provider)
      ConvertToDecimal(outputBlock, "123.456,789", provider)
      ConvertToDecimal(outputBlock, "123,456,789.0123", provider)
      ConvertToDecimal(outputBlock, "123.456.789,0123", provider)
   End Sub
End Module

' This example of
'   Convert.ToDecimal( String ) and
'   Convert.ToDecimal( String, IFormatProvider )
' generates the following output when run in the [en-US] culture.
' 
' Several strings are converted to Decimal values, using
' default formatting and a NumberFormatInfo object.
' 
' String to convert     Default/exception   Provider/exception
' -----------------     -----------------   ------------------
' 123456789             123456789           123456789
' 12345.6789            12345.6789          123456789
' 12345,6789            123456789           12345.6789
' 123,456.789           123456.789          FormatException
' 123.456,789           FormatException     123456.789
' 123,456,789.0123      123456789.0123      FormatException
' 123.456.789,0123      FormatException     123456789.0123
// Example of the Convert.ToDecimal( String ) and 
// Convert.ToDecimal( String, IFormatProvider ) methods.
using System;
using System.Globalization;

class Example
{
   static string formatter = "{0,-22}{1,-20}{2}";

   // Get the exception type name; remove the namespace prefix.
   static string GetExceptionType(Exception ex)
   {
      string exceptionType = ex.GetType().ToString();
      return exceptionType.Substring(
          exceptionType.LastIndexOf('.') + 1);
   }

   static void ConvertToDecimal(System.Windows.Controls.TextBlock outputBlock, string numericStr,
       IFormatProvider provider)
   {
      object defaultValue;
      object providerValue;

      // Convert numericStr to decimal without a format provider.
      try
      {
         defaultValue = Convert.ToDecimal(numericStr);
      }
      catch (Exception ex)
      {
         defaultValue = GetExceptionType(ex);
      }

      // Convert numericStr to decimal with a format provider.
      try
      {
         providerValue = Convert.ToDecimal(numericStr, provider);
      }
      catch (Exception ex)
      {
         providerValue = GetExceptionType(ex);
      }

      outputBlock.Text += String.Format(formatter, numericStr, defaultValue,
          providerValue) + "\n";
   }

   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      // Create a NumberFormatInfo object and set several of its
      // properties that apply to numbers.
      NumberFormatInfo provider = new NumberFormatInfo();

      provider.NumberDecimalSeparator = ",";
      provider.NumberGroupSeparator = ".";
      provider.NumberGroupSizes = new int[] { 3 };

      outputBlock.Text += String.Format(
          "This example of\n  Convert.ToDecimal( String ) and \n" +
          "  Convert.ToDecimal( String, IFormatProvider ) \n" +
          "generates the following output when run in the " +
          "[{0}] culture.",
          CultureInfo.CurrentCulture.Name) + "\n";
      outputBlock.Text += String.Format("\nSeveral " +
          "strings are converted to decimal values, using \n" +
          "default formatting and a NumberFormatInfo object.\n") + "\n";
      outputBlock.Text += String.Format(formatter, "String to convert",
          "Default/exception", "Provider/exception") + "\n";
      outputBlock.Text += String.Format(formatter, "-----------------",
          "-----------------", "------------------") + "\n";

      // Convert strings, with and without an IFormatProvider.
      ConvertToDecimal(outputBlock, "123456789", provider);
      ConvertToDecimal(outputBlock, "12345.6789", provider);
      ConvertToDecimal(outputBlock, "12345,6789", provider);
      ConvertToDecimal(outputBlock, "123,456.789", provider);
      ConvertToDecimal(outputBlock, "123.456,789", provider);
      ConvertToDecimal(outputBlock, "123,456,789.0123", provider);
      ConvertToDecimal(outputBlock, "123.456.789,0123", provider);
   }
}

/*
This example of
  Convert.ToDecimal( String ) and
  Convert.ToDecimal( String, IFormatProvider )
generates the following output when run in the [en-US] culture.

Several strings are converted to decimal values, using
default formatting and a NumberFormatInfo object.

String to convert     Default/exception   Provider/exception
-----------------     -----------------   ------------------
123456789             123456789           123456789
12345.6789            12345.6789          123456789
12345,6789            123456789           12345.6789
123,456.789           123456.789          FormatException
123.456,789           FormatException     123456.789
123,456,789.0123      123456789.0123      FormatException
123.456.789,0123      FormatException     123456789.0123
*/

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.