static void Main(string[] args) { MyClass M=new MyClass(); M.Age = 10; M.Name = "unos"; MyClass A = new MyClass(); A.Age = 20; A.Name = "reza"; M = A; // they point to the same place in memory A = null; // A got null but M's reference to memory is alive. check M M.Update(30,"meysam"); M.Update2(M); Console.ReadLine(); }