use GetHashCode as per identity and equality

If you want to unique hashcode then there are 2 ways 

1] requirement is equality mean if value contain in object should return same hashcode in this scenario you can use "Object.GetHashCode()" method.

2] requirement is identity mean if object  contain same value but different instance should

return different hashcode, you can use "RuntimeHelpers.GetHashCode" method

Here you can find same hashcode for string becuase of CLR's intern pool for string.

Example

using System.Runtime.CompilerServices;    <<<======= RuntimeHelpers class

namespace GetHashCodeSample

{

    class Program

    {

        static void Main(string[] args)

        {

            string s1 = "nitin";

            string s2 = "nitin";

            int i = 1;

            int j = 1;

            System.Console.WriteLine("Using Object's GetHashCode");

            System.Console.WriteLine("s1:{0}, s2 {1}", s1.GetHashCode(), s2.GetHashCode());

            System.Console.WriteLine("Using RuntimeHelper's GetHashCode");

            System.Console.WriteLine("s1:{0}, s2 {1}", RuntimeHelpers.GetHashCode(s1), RuntimeHelpers.GetHashCode(s2));

            System.Console.WriteLine("Using RuntimeHelper's GetHashCode");

            System.Console.WriteLine("i:{0}, j {1}", RuntimeHelpers.GetHashCode(i), RuntimeHelpers.GetHashCode(j));

            System.Console.ReadLine();

        }

    }

}

Using Object's GetHashCode

s1:-1904952336, s2 -1904952336

Using RuntimeHelper's GetHashCode

s1:37121646, s2 37121646

Using RuntimeHelper's GetHashCode

i:45592480, j 57352375