(ASP.NET) MVC View Models

    Concepts

        * What is a Viewmodel?

        * What are Viewmodels used for?

        * Viewmodel vs DTO

    Motivations

        * Decoupling

        * Differentiated output (HTML, JSON, XML, etc)

        * Progressive enhancement (render on server side, then on client side, with same shared HTML template and data structure)

        * Nice tie-in with ASP.NET MVC2 templated helpers

    Implementation

        Types of viewmodels

            [ 1) Domain entity in view ]

            2) Viewmodel per domain entity

            3) Viewmodel per domain entity + metadata (like property ACLs)

            5) Viewmodel per form

            4) Viewmodel per page

        Implementation patterns

            * AutoMapper for plumbing

                * http://automapper.codeplex.com/

            * "Who Can Help Me" style IMapper class setup on the controller level

                * http://whocanhelpme.codeplex.com/

    Questions, Concerns

        Validation

        Complexity

        Layer of indirection

        Amount of code