using System;

​

class Checker

   {

      public void Check(object param1) //STEP 2: write test 

      {

         if (param1 is ClassA)

            Console.WriteLine("Variable can be converted to ClassA.");

         else

            Console.WriteLine("Variable can't be converted to ClassA.");

         if (param1 is IMyInterface)

            Console.WriteLine("Variable can be converted to IMyInterface.");

         else

            Console.WriteLine("Variable can't be converted to IMyInterface.");

      }

   }

​

   interface IMyInterface {} //STEP 1: define classes 

​

   class ClassA : IMyInterface {} // IMPLEMENTS IMyInterface

​

   class ClassB : IMyInterface {} // IMPLEMENTS IMyInterface

​

   class ClassC {} // totally unrelated 

​

   class ClassD : ClassA {} // a CHILD of ClassA

​

public class Program

{

    public static void Main()

    {

        Checker check = new Checker(); // STEP 3

        ClassA try1 = new ClassA();

        ClassB try2 = new ClassB();

        ClassC try3 = new ClassC();

        ClassD try4 = new ClassD();

        Console.WriteLine("Analyzing ClassA type variable:");  //STEP 4: run each class through the test 

        check.Check(try1); // see line 4-17 and line 34 and 21

        Console.WriteLine("\nAnalyzing ClassB type variable:");

        check.Check(try2);// see line 4-17 and 35 and 23 

        Console.WriteLine("\nAnalyzing ClassC type variable:");

        check.Check(try3);// see line 4-17

        Console.WriteLine("\nAnalyzing ClassD type variable:");

        check.Check(try4);// see line 4-17

​

    }

}