Article
11/18/2011

Char.GetUnicodeCategory Method (String, Int32)

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Updated: December 2010

Categorizes the character at the specified position in a specified string into a group identified by one of the UnicodeCategory values.

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

Syntax

'Declaration
Public Shared Function GetUnicodeCategory ( _
    s As String, _
    index As Integer _
) As UnicodeCategory

public static UnicodeCategory GetUnicodeCategory(
    string s,
    int index
)

Parameters

s
Type: System.String
A String.

index
Type: System.Int32
The character position in s.

Return Value

Type: System.Globalization.UnicodeCategory
A UnicodeCategory enumerated constant that identifies the group that contains the character at position index in s.

Exceptions

Exception	Condition
ArgumentNullException	s is nulla null reference (Nothing in Visual Basic).
ArgumentOutOfRangeException	index is less than zero or greater than the last position in s.

Remarks

Character positions in a string are indexed starting from zero.

The GetUnicodeCategory method does not always return the same UnicodeCategory value as the CharUnicodeInfo.GetUnicodeCategory(String, Int32) method when passed a particular character as a parameter. The CharUnicodeInfo.GetUnicodeCategory(String, Int32) method is designed to reflect the current version of the Unicode standard. In contrast, although the GetUnicodeCategory method usually reflects the current version of the Unicode standard, it may return a character's category based on a previous version of the standard or it may return a category that differs from the current standard in order to preserve backward compatibility. As a result, we recommend that you use the CharUnicodeInfo.GetUnicodeCategory(Char) method instead of Char.GetUnicodeCategory(String, Int32).

Examples

The following example demonstrates GetUnicodeCategory.


Module Example
   Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      Dim ch2 As Char
      ch2 = "2"c
      Dim str As String
      str = "Upper Case"

      outputBlock.Text &= Char.GetUnicodeCategory("a"c) & vbCrLf   
      outputBlock.Text &= Char.GetUnicodeCategory(ch2) & vbCrLf       
      outputBlock.Text &= Char.GetUnicodeCategory(str, 6) & vbCrLf  
   End Sub
End Module
' The example displays the following output:
'       LowercaseLetter
'       DecimalDigitNumber
'       UppercaseLetter

using System;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      char ch2 = '2';
      string str = "Upper Case";

      outputBlock.Text += Char.GetUnicodeCategory('a') + "\n";      
      outputBlock.Text += Char.GetUnicodeCategory(ch2) + "\n";      
      outputBlock.Text += Char.GetUnicodeCategory(str, 6) + "\n";   
   }
}
// The example displays the following output:
//       LowercaseLetter
//       DecimalDigitNumber
//       UppercaseLetter

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.

Change History

Date	History	Reason
December 2010	Noted that the CharUnicodeInfo.GetUnicodeCategory method is recommended.	Information enhancement.

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