C# String IsNullOrEmpty

Description

String IsNullOrEmpty indicates whether the specified string is null or an Empty string.

Syntax

String.IsNullOrEmpty has the following syntax.


public static bool IsNullOrEmpty(
  string value
)

Parameters

String.IsNullOrEmpty has the following parameters.

value - The string to test.

Returns

String.IsNullOrEmpty method returns true if the value parameter is null or an empty string (""); otherwise, false.

Example

The following example examines three strings and determines whether each string has a value, is an empty string, or is null.


using System;/*from w  ww  .j a v a  2  s . co  m*/

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 neither null nor empty", s);
    }
}

The code above generates the following result.