Convert.ToSingle Method (String, IFormatProvider)

Parameters

• value
  Type: System.String
  A String containing a number to convert.

• provider
  Type: System.IFormatProvider
  An IFormatProvider interface implementation that supplies culture-specific formatting information.

Return Value

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

' Example of the Convert.ToSingle( String ) and 
' Convert.ToSingle( 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 ConvertToSingle(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 Single without a format provider.
      Try
         defaultValue = Convert.ToSingle(numericStr)
      Catch ex As Exception
         defaultValue = GetExceptionType(ex)
      End Try

      ' Convert numericStr to Single with a format provider.
      Try
         providerValue = Convert.ToSingle(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.ToSingle( String ) and " & vbCrLf & _
          "  Convert.ToSingle( 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 Single 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.
      ConvertToSingle(outputBlock, "1234567", provider)
      ConvertToSingle(outputBlock, "1234.567", provider)
      ConvertToSingle(outputBlock, "1234,567", provider)
      ConvertToSingle(outputBlock, "12,345.67", provider)
      ConvertToSingle(outputBlock, "12.345,67", provider)
      ConvertToSingle(outputBlock, "1,234,567.89", provider)
      ConvertToSingle(outputBlock, "1.234.567,89", provider)
   End Sub
End Module

' This example of
'   Convert.ToSingle( String ) and
'   Convert.ToSingle( String, IFormatProvider )
' generates the following output when run in the [en-US] culture.
' 
' Several strings are converted to Single values, using
' default formatting and a NumberFormatInfo object.
' 
' String to convert     Default/exception   Provider/exception
' -----------------     -----------------   ------------------
' 1234567               1234567             1234567
' 1234.567              1234.567            1234567
' 1234,567              1234567             1234.567
' 12,345.67             12345.67            FormatException
' 12.345,67             FormatException     12345.67
' 1,234,567.89          1234568             FormatException
' 1.234.567,89          FormatException     1234568

// Example of the Convert.ToSingle( String ) and 
// Convert.ToSingle( 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 ConvertToSingle(System.Windows.Controls.TextBlock outputBlock, string numericStr,
       IFormatProvider provider)
   {
      object defaultValue;
      object providerValue;

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

      // Convert numericStr to float with a format provider.
      try
      {
         providerValue = Convert.ToSingle(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.ToSingle( String ) and \n" +
          "  Convert.ToSingle( 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 float 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.
      ConvertToSingle(outputBlock, "1234567", provider);
      ConvertToSingle(outputBlock, "1234.567", provider);
      ConvertToSingle(outputBlock, "1234,567", provider);
      ConvertToSingle(outputBlock, "12,345.67", provider);
      ConvertToSingle(outputBlock, "12.345,67", provider);
      ConvertToSingle(outputBlock, "1,234,567.89", provider);
      ConvertToSingle(outputBlock, "1.234.567,89", provider);
   }
}

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

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

String to convert     Default/exception   Provider/exception
-----------------     -----------------   ------------------
1234567               1234567             1234567
1234.567              1234.567            1234567
1234,567              1234567             1234.567
12,345.67             12345.67            FormatException
12.345,67             FormatException     12345.67
1,234,567.89          1234568             FormatException
1.234.567,89          FormatException     1234568
*/