Use the inherited Object methods: Equals : System.Object « Class « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. Class
3. System.Object

using System;

class MainClass
{
    public static void Main(string[] args)
    {
    MainClass c1 = new MainClass();

    MainClass c2 = c1;
    object o = c2;
    
    if(o.Equals(c1) && c2.Equals(o))
      Console.WriteLine("Same instance!\n");

    }
}

Same instance!