using System;

using System.Linq;

using System.Collections.Generic;

using System.Threading.Tasks;

using System.Reflection;

public class Program

{

    public static void Main()

    {       

        long? a = 10;

        long? b = 10;

        var rs = a.Comparexxx<long>(b);

        Console.WriteLine(rs);

    }

}

​

public static class AttributeExtensions

    {

        public static bool Comparexxx<T>(this T? myValue, T? otherValue)

            where T : struct

            { 

                var comparer = new NullableComparer<T>();

                return comparer.Compare(myValue, otherValue) == 1 ? true : false;               

            } 

            public class NullableComparer<T> : IComparer<Nullable<T>>

                  where T : struct

            {

                 public int Compare(Nullable<T> x, Nullable<T> y)

                 {

                    //Compare nulls acording MSDN specification

                    //Two nulls are equal

                    if (!x.HasValue && !y.HasValue)

                        return 0;

                    //Any object is greater than null

                    if (x.HasValue && !y.HasValue) 

                        return 1;

                    if (y.HasValue && !x.HasValue)

                        return -1;

                    //Otherwise compare the two values

                    return x.Value.Equals(y.Value) ? 1 : 0 ;

                 }

            }

    }

​

​