String.IsNullOrWhiteSpace Method (System)

.NET Framework Class Library

String..::.IsNullOrWhiteSpace Method

Indicates whether a specified string is nullNothingnullptra null reference (Nothing in Visual Basic), empty, or consists only of white-space characters.

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

Syntax

Public Shared Function IsNullOrWhiteSpace ( _
	value As String _
) As Boolean

public static bool IsNullOrWhiteSpace(
	string value
)

public:
static bool IsNullOrWhiteSpace(
	String^ value
)

static member IsNullOrWhiteSpace : 
        value:string -> bool

Parameters

value: Type: System..::.String
The string to test.

Return Value

Type: System..::.Boolean
true if the value parameter is nullNothingnullptra null reference (Nothing in Visual Basic) or String..::.Empty, or if value consists exclusively of white-space characters.

Remarks

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


Return String.IsNullOrEmpty(value) OrElse value.Trim().Length = 0


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.

Examples

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


Module Example
   Public Sub Main()
      Dim values() As String = { Nothing, String.Empty, "ABCDE", 
                                 New String(" "c, 20), "  " + vbTab + "   ", 
                                 New String(ChrW(&h2000), 10) }
      For Each value As String In values
         Console.WriteLine(String.IsNullOrWhiteSpace(value))
      Next
   End Sub
End Module
' The example displays the following output:
'       True
'       True
'       False
'       True
'       True
'       True


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)
         Console.WriteLine(String.IsNullOrWhiteSpace(value));
   }
}
// The example displays the following output:
//       True
//       True
//       False
//       True
//       True
//       True

Version Information

.NET Framework

Supported in: 4

.NET Framework Client Profile

Supported in: 4

Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, 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.

Reference

String Class

System Namespace

IsNullOrEmpty