This documentation is archived and is not being maintained.

Char.IsControl Method (String, Int32)

.NET Framework 1.1

Indicates whether the character at the specified position in a specified string is categorized as a control character.

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


A string.
The character position in s.

Return Value

true if the character at position index in s is a control character; 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 control characters are members of the following category in UnicodeCategory: Control.


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

[Visual Basic] 
imports System

Module IsControlSample

    Sub Main()

        Dim chTab As Char
        chTab = Chr(9)      ' Tab character
        Dim str As String
        str = "sample string"

        Console.WriteLine(Char.IsControl(chTab))    ' Output: "True"
        Console.WriteLine(Char.IsControl(str, 6))   ' Output: "False"

    End Sub

End Module

using System;

public class IsControlSample {
    public static void Main() {
        string str = "sample string";

        Console.WriteLine(Char.IsControl('\t'));    // Output: "True"
        Console.WriteLine(Char.IsControl(str, 7));    // Output: "False"

#using <mscorlib.dll>
using namespace System;

int main() {
    String* str = "sample string";

    Console::WriteLine(Char::IsControl('\t'));    // Output: "True"
    Console::WriteLine(Char::IsControl(str, 7));    // Output: "False"

[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.IsControl Overload List | Boolean