using System;

using System.Linq;

​

namespace HelloWorld

{

 class Aggregate {}

 class Listing : Aggregate {}

 interface IAction<TA> {}

 interface IAggregateAction<TA, out TB> : IAction<TA> where TB : Aggregate {

 }

 class CreateListingAction: IAggregateAction<string, Listing> {}

  class Program

  {

    static void Main(string[] args)

    {

     var myAction = new CreateListingAction();

      Console.WriteLine($"myAction is IAction<string> {myAction is IAction<string>}");   

              Console.WriteLine($"myAction is IAction<string> {myAction is not null}");    

​

      Console.WriteLine($"myAction is IAggregateAction<string,Listing> {myAction is IAggregateAction<string,Listing>}");    

      Console.WriteLine($"myAction is IAggregateAction<string,Aggregate> {myAction is IAggregateAction<string,Aggregate>}");    

​

        IAggregateAction<string, Aggregate> myAggregateAction = myAction as IAggregateAction<string, Aggregate>;

      Console.WriteLine($"Cast success?: {myAggregateAction != null}");

    }

  }

}