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Char.IsLetterOrDigit Method (String, Int32)

.NET Framework 1.1

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

[Visual Basic]
Overloads Public Shared Function IsLetterOrDigit( _
   ByVal s As String, _
   ByVal index As Integer _
) As Boolean
public static bool IsLetterOrDigit(
 string s,
 int index
public: static bool IsLetterOrDigit(
 String* s,
 int index
public static function IsLetterOrDigit(
   s : String,
 index : int
) : Boolean;


A string.
The character position in s.

Return Value

true if the character at position index in s is an alphabetic character or a decimal digit; otherwise, false.


Exception Type Condition
ArgumentNullException s is a null reference (Nothing in Visual Basic).
ArgumentOutOfRangeException 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.


[Visual Basic, C#, C++] The following sample demonstrates IsLetterOrDigit.

[Visual Basic] 
imports System

Module IsLetterOrDigitSample

    Sub Main()

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

        Console.WriteLine(Char.IsLetterOrDigit("8"c))       ' Output: "True"
        Console.WriteLine(Char.IsLetterOrDigit(str, 8))     ' Output: "False", because it's a NewLine

    End Sub

End Module

using System;

public class IsLetterOrDigitSample {
    public static void Main() {
        string str = "newline:\n";

        Console.WriteLine(Char.IsLetterOrDigit('8'));        // Output: "True"
        Console.WriteLine(Char.IsLetterOrDigit(str, 8));    // Output: "False", because it's a newline

#using <mscorlib.dll>
using namespace System;

int main() {
   String* str = "newline:\n";

   Console::WriteLine(Char::IsLetterOrDigit('8'));      // Output: "True"
   Console::WriteLine(Char::IsLetterOrDigit(str, 8));   // Output: "False", because it's a newline

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.


Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, Common Language Infrastructure (CLI) Standard

See Also

Char Structure | Char Members | System Namespace | Char.IsLetterOrDigit Overload List | Boolean