Windows apps
Collapse the table of content
Expand the table of content
The topic you requested is included in another documentation set. For convenience, it's displayed below. Choose Switch to see the topic in its original location.

Char.IsLetterOrDigit Method (String, Int32)

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)

public static bool IsLetterOrDigit(
	string s,
	int index


Type: System.String
A string.
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.


s is null.


index is less than zero or greater than the last position in s.

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.

The following example demonstrates IsLetterOrDigit.

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


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

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

© 2018 Microsoft