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String.IsNullOrEmpty Method

Note: This method is new in the .NET Framework version 2.0.

Indicates whether the specified String object is a null reference (Nothing in Visual Basic) or an Empty string.

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

'Declaration
Public Shared Function IsNullOrEmpty ( _
	value As String _
) As Boolean
'Usage
Dim value As String
Dim returnValue As Boolean

returnValue = String.IsNullOrEmpty(value)
public static boolean IsNullOrEmpty (
	String value
)
public static function IsNullOrEmpty (
	value : String
) : boolean

Parameters

value

A String reference.

Return Value

true if the value parameter is a null reference (Nothing in Visual Basic) or an empty string (""); otherwise, false.

IsNullOrEmpty is a convenience method that enables you to simultaneously test whether a String is a null reference (Nothing in Visual Basic) or its value is Empty.

The following code example determines whether each of three strings has a value, is an empty string or is a null reference (Nothing in Visual Basic).

' This example demonstrates the String.IsNullOrEmpty() method
Imports System

Class Sample
   Public Shared Sub Main()
      Dim s1 As String = "abcd"
      Dim s2 As String = ""
      Dim s3 As String = Nothing
      
      Console.WriteLine("String s1 {0}.", Test(s1))
      Console.WriteLine("String s2 {0}.", Test(s2))
      Console.WriteLine("String s3 {0}.", Test(s3))
   End Sub 'Main
   
   Public Shared Function Test(s As String) As [String]
      If [String].IsNullOrEmpty(s) = True Then
         Return "is null or empty"
      Else
         Return String.Format("(""{0}"") is not null or empty", s)
      End If
   End Function 'Test
End Class 'Sample 
'
'This example produces the following results:
'
'String s1 ("abcd") is not null or empty.
'String s2 is null or empty.
'String s3 is null or empty.
'

// This example demonstrates the String.IsNullOrEmpty() method
import System.*;

class Sample
{
    public static void main(String[] args)
    {
        String s1 = "abcd";
        String s2 = "";
        String s3 = null;

        Console.WriteLine("String s1 {0}.", Test(s1));
        Console.WriteLine("String s2 {0}.", Test(s2));
        Console.WriteLine("String s3 {0}.", Test(s3));
    } //main

    public static String Test(String s)
    {
        if (String.IsNullOrEmpty(s) == true) {
            return "is null or empty";
        }
        else {
            return String.Format("(\"{0}\") is not null or empty", s);
        }
    } //Test
} //Sample 
 /*
This example produces the following results:

String s1 ("abcd") is not null or empty.
String s2 is null or empty.
String s3 is null or empty.

*/

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

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

.NET Framework

Supported in: 2.0

.NET Compact Framework

Supported in: 2.0
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