using System;

public class Program

{

    public static void Main()

    {

        string test = null;

        Console.WriteLine("Hello World");

        if (test.HasValue()) {

            Console.WriteLine("Nope");

        }

    }   

}

​

public static class StringExtensions {

    public static bool HasValue(this string text) {

        return string.IsNullOrWhiteSpace(text);

    }

}