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String.IsNullOrWhiteSpace Method

Indicates whether a specified string is Nothing, empty, or consists only of white-space characters.

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

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

Parameters

value
Type: System.String
The string to test.

Return Value

Type: System.Boolean
true if the value parameter is Nothing 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) OrElse 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.


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


.NET Framework

Supported in: 4

.NET Framework Client Profile

Supported in: 4

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.
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