IsNullOrWhiteSpace Method

String.IsNullOrWhiteSpace Method (String)


Indicates whether a specified string is null, empty, or consists only of white-space characters.

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

public static bool IsNullOrWhiteSpace(
	string value


Type: System.String

The string to test.

Return Value

Type: System.Boolean

true if the value parameter is null or String.Empty, or if value consists exclusively of white-space characters.

IsNullOrWhiteSpace is a convenience method that is similar to the following code, except that it offers superior performance:

return String.IsNullOrEmpty(value) || value.Trim().Length == 0;

White-space characters are defined by the Unicode standard. The IsNullOrWhiteSpace method interprets any character that returns a value of true when it is passed to the Char.IsWhiteSpace method as a white-space character.

The following example creates a string array, and then passes each element of the array to the IsNullOrWhiteSpace method.

using System;

public class Example
   public static void Main()
      string[] values = { null, String.Empty, "ABCDE", 
                          new String(' ', 20), "  \t   ", 
                          new String('\u2000', 10) };
      foreach (string value in values)
// The example displays the following output:
//       True
//       True
//       False
//       True
//       True
//       True

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Available since 4.0
Windows Phone Silverlight
Available since 7.1
Windows Phone
Available since 8.1
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