Indicates whether the specified String object is nullNothingnullptra null reference (Nothing in Visual Basic) or an Empty string.
(in mscorlib.dll)
Visual Basic (Declaration)
Public Shared Function IsNullOrEmpty ( _
value As String _
) As Boolean
Dim value As String
Dim returnValue As Boolean
returnValue = String.IsNullOrEmpty(value)
public static bool IsNullOrEmpty(
string value
)
public:
static bool IsNullOrEmpty(
String^ value
)
public static function IsNullOrEmpty(
value : String
) : boolean
Return Value
Type:
System..::.Boolean
true if the value parameter is nullNothingnullptra 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 nullNothingnullptra null reference (Nothing in Visual Basic) or its value is Empty.
The following example determines whether each of three strings has a value, is an empty string or is nullNothingnullptra 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
using System;
class Sample
{
public static void Main()
{
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));
}
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);
}
}
/*
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
using namespace System;
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 );
}
int main()
{
String^ s1 = "abcd";
String^ s2 = "";
String^ s3 = nullptr;
Console::WriteLine( "String s1 {0}.", Test( s1 ) );
Console::WriteLine( "String s2 {0}.", Test( s2 ) );
Console::WriteLine( "String s3 {0}.", Test( s3 ) );
}
/*
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 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
.NET Framework
Supported in: 3.5, 3.0, 2.0
.NET Compact Framework
Supported in: 3.5, 2.0
XNA Framework
Supported in: 3.0, 2.0, 1.0
Reference