Updated: December 2010
Indicates whether the specified string is
Assembly: mscorlib (in mscorlib.dll)
Syntax . . :: . Boolean
true if the value parameter isnull Nothing nullptr a null reference (Nothing in Visual Basic) or an empty string (""); otherwise, false.
Public Shared Function IsNullOrEmpty ( _
value As String _
) As Booleanpublic static bool IsNullOrEmpty(
string value
)public:
static bool IsNullOrEmpty(
String^ value
)static member IsNullOrEmpty :
value:string -> bool
Parameters
- value
- Type: System
. . :: . String
The string to test.
Return Value
Type: Systemtrue if the value parameter is
Remarks
IsNullOrEmpty is a convenience method that enables you to simultaneously test whether a String is
result = s Is Nothing OrElse s = String.Empty
result = s == null || s == String.Empty;
result = s == nullptr || s == String::Empty;
Examples
The following example determines whether each of three strings has a value, is an empty string or is
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
Public Shared Function Test(s As String) As String
If String.IsNullOrEmpty(s) Then
Return "is null or empty"
Else
Return String.Format("(""{0}"") is not null or empty", s)
End If
End Function
End Class
' The example displays the following output:
' String s1 ("abcd") is not null or empty.
' String s2 is null or empty.
' String s3 is null or empty.
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))
return "is null or empty";
else
return String.Format("(\"{0}\") is not null or empty", s);
}
}
// The example displays the following output:
// String s1 ("abcd") is not null or empty.
// String s2 is null or empty.
// String s3 is null or empty.
using namespace System;
String^ Test( String^ s )
{
if (String::IsNullOrEmpty(s))
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 ) );
}
// The example displays the following output:
// String s1 ("abcd") is not null or empty.
// String s2 is null or empty.
// String s3 is null or empty.
Platforms
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, 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.