using System;

using System.Collections.Generic;

​

public interface IViewEngine

{

    string Render(string viewName, Dictionary<string, object> context);

}

​

public class MatchaViewEngine: IViewEngine

{

    public string Render(string viewName, Dictionary<string, object> context)

    {

        return "View Rendered by Matcha";

    }

}

​

public class SharpViewEngine: IViewEngine

{

    public string Render(string viewName, Dictionary<string, object> context)

    {

        return "View Rendered by Sharp";

    }

}

​

public class Controller

{

    public void Render(string viewName, Dictionary<string, object> context)

    {

        var viewEngine = CreateViewEngine();

        var html = viewEngine.Render(viewName, context);

        Console.WriteLine(html);

    }

​

    protected virtual IViewEngine CreateViewEngine()

    {

        return new MatchaViewEngine();

    }

}

​

public class SharpController: Controller

{

    protected override IViewEngine CreateViewEngine()

    {

        return new SharpViewEngine();

    }

}

​

public class ProductsController: SharpController

{

    public void ListProducts()

    {

        Dictionary<string, object> context = new Dictionary<string, object>();

        Render("products.html", context);

    }

}

​

​

public class Program

{

    public static void Main()

    {

        ProductsController controller = new ProductsController();

        controller.ListProducts();

    }

}