using System;

using System.Collections.Generic;

​

public static class StringExtensions

{

    public static bool isEmpty(this string _str)

    {

        return _str == "";

    }

    public static bool hasContent(this string _str)

    {

        return _str != null && _str.Length > 0;

    }

}

​

public class Program

{

​

    public static void Main()

    {

        var strings = new List<string>()

        {

            "word",

            "",

            null,

        };

        foreach(var str in strings)

        {

            Console.WriteLine("isEmpty[" + str.isEmpty() + "]");

            Console.WriteLine("hasContent[" + str.hasContent() + "]\n");

        }

    }

}