using System;

​

public class Program

{

    public abstract class EventBase

    {

    }

    public class Event1 : EventBase

    {

    }

    public class Event2 : EventBase

    {

    }

    private static void Foo(EventBase eventBase)

    {

        Bar((dynamic)eventBase);

    }

    private static void Bar(object param)

    {

        Console.WriteLine("object Bar");

    }

    public static void Bar(Event1 param)

    {

        Console.WriteLine("Event1 Bar");

    }

    public static void Bar(Event2 param)

    {

        Console.WriteLine("Event2 Bar");

    }

​

    public static void Main()

    {

        Foo(new Event1());

        Foo(new Event2());

    }

}