• Article

Char.IsLetterOrDigit Method (String, Int32)

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

Indicates whether the character at the specified position in a specified string is categorized as a letter or a decimal digit.

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

Syntax

'Declaration
Public Shared Function IsLetterOrDigit ( _
    s As String, _
    index As Integer _
) As Boolean

public static bool IsLetterOrDigit(
    string s,
    int index
)

Parameters

  • index
    Type: System.Int32
    The position of the character to evaluate in s.

Return Value

Type: System.Boolean
true if the character at position index in s is a letter or a decimal digit; otherwise, false.

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.

Valid alphabetic letters and decimal digits are members of the following categories in UnicodeCategory: UppercaseLetter, LowercaseLetter, TitlecaseLetter, ModifierLetter, OtherLetter, or DecimalDigitNumber.

Examples

The following example demonstrates IsLetterOrDigit.


Module Example

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

      Dim str As String
      str = "newline:" + vbNewLine

      outputBlock.Text &= Char.IsLetterOrDigit("8"c) & vbCrLf       ' Output: "True"
      outputBlock.Text += String.Format(Char.IsLetterOrDigit(str, 8)) & vbCrLf     ' Output: "False", because it's a NewLine

   End Sub

End Module

using System;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      string str = "newline:\n";

      outputBlock.Text += Char.IsLetterOrDigit('8').ToString() + "\n";  
      outputBlock.Text += (Char.IsLetterOrDigit(str, 8).ToString()) + "\n";
   }
}
// The example displays the following output:
//    True
//    False

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.