C# check if DateTime variable is null

using System;

using System.Text;

namespace ConsoleApplication

{

    class Program

    {

        static void Main(string[] args)

        {

            DateTime dt1 = new DateTime();

            DateTime? dt2=null ;

            isDateTimeNull(dt1);

            isDateTimeNull(dt2);

        }

        static void isDateTimeNull(DateTime? dt)

        {

            if(dt.GetHashCode()==0)

            {

                Console.WriteLine("DateTime is unassigned");

            }

        }

    }

}

Output:

In stackoverflow.com I found another way for checking null datetime

 DateTime datetime = new DateTime();

 if (datetime == DateTime.MinValue)

 {

    //unassigned

 }