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.NET Framework 3.5
System Namespace
Char Structure
Char Methods
IsDigit Method
 IsDigit Method (Char)

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This page is specific to
Microsoft Visual Studio 2008/.NET Framework 3.5

Other versions are also available for the following:
.NET Framework Class Library
Char..::.IsDigit Method (Char)

Updated: October 2008

Indicates whether the specified Unicode character is categorized as a decimal digit.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)
Visual Basic (Declaration)
Public Shared Function IsDigit ( _
    c As Char _
) As Boolean
Visual Basic (Usage)
Dim c As Char
Dim returnValue As Boolean

returnValue = Char.IsDigit(c)
C#
public static bool IsDigit(
    char c
)
Visual C++
public:
static bool IsDigit(
    wchar_t c
)
JScript
public static function IsDigit(
    c : char
) : boolean

Parameters

c
Type: System..::.Char
A Unicode character.

Return Value

Type: System..::.Boolean
true if c is a decimal digit; otherwise, false.

This method determines if a Char is a radix-10 digit. This contrasts with the IsNumber method, which determines if a Char is of any numeric Unicode category. Numbers include characters such as fractions, subscripts, superscripts, Roman numerals, currency numerators, encircled numbers, and script-specific digits.

Valid digits are members of the UnicodeCategory..::.DecimalDigitNumber category.

The following code example demonstrates IsDigit.

Visual Basic
Imports System

Module IsDigitSample

    Sub Main()

        Dim ch8 As Char
        ch8 = "8"c

        Console.WriteLine(Char.IsDigit(ch8))                    ' Output: "True"
        Console.WriteLine(Char.IsDigit("sample string", 6))     ' Output: "False"

    End Sub

End Module

C#
using System;

public class IsDigitSample {
    public static void Main() {
        char ch = '8';

        Console.WriteLine(Char.IsDigit(ch));                    // Output: "True"
        Console.WriteLine(Char.IsDigit("sample string", 7));    // Output: "False"
    }
}

Visual C++
using namespace System;
int main()
{
   char ch = '8';
   Console::WriteLine( Char::IsDigit( ch ) ); // Output: "True"
   Console::WriteLine( Char::IsDigit(  "sample string", 7 ) ); // Output: "False"
}


Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Date

History

Reason

October 2008

Added detail about the difference between the IsDigit and IsNumber methods.

Customer feedback.

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