Convert.ToByte 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.Byte
An 8-bit signed integer equivalent to the value of value.
-or-
Zero if value is nulla null reference (Nothing in Visual Basic).

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

Module Example

   Dim format As String = "{0,-20}{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()
      Return exceptionType.Substring( _
          exceptionType.LastIndexOf("."c) + 1)
   End Function

   Sub ConvertToByte(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 Byte without a format provider.
      Try
         defaultValue = Convert.ToByte(numericStr)
      Catch ex As Exception
         defaultValue = GetExceptionType(ex)
      End Try

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

      outputBlock.Text &= String.Format(format, 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()

      ' These properties affect the conversion.
      provider.PositiveSign = "pos "
      provider.NegativeSign = "neg "

      ' These properties do not affect the conversion.
      ' The input string cannot have decimal and group separators.
      provider.NumberDecimalSeparator = "."

      outputBlock.Text &= String.Format("This example of" & vbCrLf & _
          "  Convert.ToByte( String ) and " & vbCrLf & _
          "  Convert.ToByte( String, IFormatProvider ) " & _
          vbCrLf & "generates the following output. It " & _
          "converts several strings to " & vbCrLf & "Byte " & _
          "values, using default formatting " & _
          "or a NumberFormatInfo object." & vbCrLf) & vbCrLf
      outputBlock.Text &= String.Format(format, "String to convert", _
          "Default/exception", "Provider/exception") & vbCrLf
      outputBlock.Text &= String.Format(format, "-----------------", _
          "-----------------", "------------------") & vbCrLf

      ' Convert strings, with and without an IFormatProvider.
      ConvertToByte(outputBlock, "234", provider)
      ConvertToByte(outputBlock, "+234", provider)
      ConvertToByte(outputBlock, "pos 234", provider)
      ConvertToByte(outputBlock, "234.", provider)
      ConvertToByte(outputBlock, "255", provider)
      ConvertToByte(outputBlock, "256", provider)
      ConvertToByte(outputBlock, "-1", provider)
   End Sub
End Module

' This example of
'   Convert.ToByte( String ) and
'   Convert.ToByte( String, IFormatProvider )
' generates the following output. It converts several strings to
' Byte values, using default formatting or a NumberFormatInfo object.
' 
' String to convert   Default/exception   Provider/exception
' -----------------   -----------------   ------------------
' 234                 234                 234
' +234                234                 FormatException
' pos 234             FormatException     234
' 234.                FormatException     FormatException
' 255                 255                 255
' 256                 OverflowException   OverflowException
' -1                  OverflowException   FormatException

// Example of the Convert.ToByte( string ) and 
// Convert.ToByte( string, IFormatProvider ) methods.
using System;
using System.Globalization;

class Example
{
   static string format = "{0,-20}{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 ConvertToByte(System.Windows.Controls.TextBlock outputBlock, string numericStr,
       IFormatProvider provider)
   {
      object defaultValue;
      object providerValue;

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

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

      outputBlock.Text += String.Format(format, 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();

      // These properties affect the conversion.
      provider.NegativeSign = "neg ";
      provider.PositiveSign = "pos ";

      // These properties do not affect the conversion.
      // The input string cannot have decimal and group separators.
      provider.NumberDecimalSeparator = ".";

      outputBlock.Text += String.Format("This example of\n" +
          "  Convert.ToByte( string ) and \n" +
          "  Convert.ToByte( string, IFormatProvider ) " +
          "\ngenerates the following output. It converts " +
          "several strings to \nbyte values, using " +
          "default formatting or a NumberFormatInfo object.\n") + "\n";
      outputBlock.Text += String.Format(format, "String to convert",
          "Default/exception", "Provider/exception") + "\n";
      outputBlock.Text += String.Format(format, "-----------------",
          "-----------------", "------------------") + "\n";

      // Convert strings, with and without an IFormatProvider.
      ConvertToByte(outputBlock, "234", provider);
      ConvertToByte(outputBlock, "+234", provider);
      ConvertToByte(outputBlock, "pos 234", provider);
      ConvertToByte(outputBlock, "234.", provider);
      ConvertToByte(outputBlock, "255", provider);
      ConvertToByte(outputBlock, "256", provider);
      ConvertToByte(outputBlock, "-1", provider);
   }
}

/*
This example of
  Convert.ToByte( string ) and
  Convert.ToByte( string, IFormatProvider )
generates the following output. It converts several strings to
byte values, using default formatting or a NumberFormatInfo object.

String to convert   Default/exception   Provider/exception
-----------------   -----------------   ------------------
234                 234                 234
+234                234                 FormatException
pos 234             FormatException     234
234.                FormatException     FormatException
255                 255                 255
256                 OverflowException   OverflowException
-1                  OverflowException   FormatException
*/