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Char.IsControl Method (String, Int32)


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

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

public static bool IsControl(
	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 control character; otherwise, false.

Exception Condition

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.

Control characters are formatting and other non-printing characters, such as ACK, BEL, CR, FF, LF, and VT. The Unicode standard assigns code points from \U0000 to \U001F, \U007F, and from \U0080 to \U009F to control characters. According to the Unicode standard, these values are to be interpreted as control characters unless their use is otherwise defined by an application. Valid control characters are members of the UnicodeCategory.Control category.

The following example enumerates the characters in a string and determines whether any are control characters.

using System;

public class ControlChar
   public static void Main()
      string sentence = "This is a " + Environment.NewLine + "two-line sentence.";
      for (int ctr = 0; ctr < sentence.Length; ctr++)
         if (Char.IsControl(sentence, ctr))
           Console.WriteLine("Control character \\U{0} found in position {1}.", 
             Convert.ToInt32(sentence[ctr]).ToString("X4"), ctr);

// The example displays the following output to the console:
//       Control character \U000D found in position 10.
//       Control character \U000A found in position 11.

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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