String.IsNullOrEmpty Method
.NET Framework 2.0
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)
Assembly: mscorlib (in mscorlib.dll)
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.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 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
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.
