using System;

public class Program

{

    public static void Main()

    {

        var mainClass = new MainClass();

        mainClass.Test();

    }

}

​

    class MainClass

    {

        int mode = 31416;

        ObjectA obj = new ObjectA();

        public MainClass() 

        {

            obj.ValueReturnEvent += HandleValueReturnEvent;

        }

        public int GetMainClassMode() 

        {

            return mode;

        }

        // Handle event, return data

        private int HandleValueReturnEvent(object sender, EventArgs e)

        {

            return mode;

        }

        public void Test() {

            Console.WriteLine("Calling test method inside obj");

            obj.Test();

        }

    }

    class ObjectA {

        // delegate

        public delegate int ReturnValueEventHandler(object sender, EventArgs args);

        // event

        public event ReturnValueEventHandler ValueReturnEvent;

        public void Test() 

        {

            // make sure at least one subscriber

            if (ValueReturnEvent != null)  

            {

                // note the event is returning a value

                var myValue = ValueReturnEvent(this, null);

                Console.WriteLine("Getting mode from 'parent' MainClass");

                Console.WriteLine(string.Format("Mode = {0}", myValue));

            }

        }   

    }