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String.Trim Method (Char[])

Removes all leading and trailing occurrences of a set of characters specified in an array from the current String object.

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

public string Trim(
	params char[] trimChars
)

Parameters

trimChars
Type: System.Char[]
An array of Unicode characters to remove, or null.

Return Value

Type: System.String
The string that remains after all occurrences of the characters in the trimChars parameter are removed from the start and end of the current string. If trimChars is null or an empty array, white-space characters are removed instead.

The Trim method removes from the current string all leading and trailing characters that are in the trimChars parameter. Each leading and trailing trim operation stops when a character that is not in trimChars is encountered. For example, if the current string is "123abc456xyz789" and trimChars contains the digits from "1" through "9", the Trim method returns "abc456xyz".

NoteNote

This method does not modify the value of the current instance. Instead, it returns a new string in which all leading and trailing trimChars characters found in the current instance are removed.

If the current string equals Empty or all the characters in the current instance consist of characters in the trimChars array, the method returns Empty.

If trimChars is null or an empty array, this method removes any leading or trailing characters that result in the method returning true when they are passed to the Char.IsWhiteSpace method,

Notes to Callers

The .NET Framework 3.5 SP1 and earlier versions maintains an internal list of white-space characters that this method trims if trimChars is null or an empty array. Starting with the .NET Framework 4, if trimChars is null or an empty array, the method trims all Unicode white-space characters (that is, characters that produce a true return value when they are passed to the Char.IsWhiteSpace method). Because of this change, the Trim method in the .NET Framework 3.5 SP1 and earlier versions removes two characters, ZERO WIDTH SPACE (U+200B) and ZERO WIDTH NO-BREAK SPACE (U+FEFF), that the Trim method in the .NET Framework 4 does not remove. In addition, the Trim method in the .NET Framework 3.5 SP1 and earlier versions does not trim three Unicode white-space characters: MONGOLIAN VOWEL SEPARATOR (U+180E), NARROW NO-BREAK SPACE (U+202F), and MEDIUM MATHEMATICAL SPACE (U+205F).

The following example uses the String.Trim(Char[]) method to remove space, asterisk (*), and apostrophe (') characters from a string.


using System;

public class Example
{
   public static void Main()
   {
      char[] charsToTrim = { '*', ' ', '\''};
      string banner = "*** Much Ado About Nothing ***";
      string result = banner.Trim(charsToTrim);
      Console.WriteLine("Trimmmed\n   {0}\nto\n   '{1}'", banner, result);
   }
}
// The example displays the following output:
//       Trimmmed
//          *** Much Ado About Nothing ***
//       to
//          'Much Ado About Nothing'


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

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