ASP.NET MVC ViewModel Pattern

Question

EDIT: I made something much better to fill and read data from a view using ViewModels, called it ValueInjecter. http://valueinjecter.codeplex.com/

it is used by http://prodinner.codeplex.com - an ASP.net MVC sample application

you can see the best way of using ViewModels in prodinner

using the ViewModel to store the mapping logic was not such a good idea because there was repetition and SRP violation, but now with the ValueInjecter I have clean ViewModels and dry mapping code

---

That's the old stuff, don't use it:
I made a ViewModel pattern for editing stuff in asp.net mvc this pattern is useful when you have to make a form for editing an entity and you have to put on the form some drop-downs for the user to choose some values

    public class OrganisationBadViewModel
    {
        //paramterless constructor required, cuz we are gonna get an OrganisationViewModel object from the form in the post save method
        public OrganisationViewModel() : this(new Organisation()) {}
        public OrganisationViewModel(Organisation o)
        {
            Organisation = o;
            Country = new SelectList(LookupFacade.Country.GetAll(), "ID", "Description", CountryKey);  
        }       
        //that's the Type for whom i create the viewmodel
        public Organisation Organisation { get; set; }
...     

    }

Answer 1

This looks very similar to the recommended practice in the Wrox Professional ASP.NET MVC book, the first chapter of which is available for free from the above URL.

Starting on page 100 they have a section on ViewData and ViewModels.

When a Controller class decides to render an HTML response back to a client, it is responsible for explicitly passing to the view template all of the data needed to render the response. View templates should never perform any data retrieval or application logic – and should instead limit themselves to only have rendering code that is driven off of the model/data passed to it by the controller.

[...]

When using [the "ViewModel"] pattern we create strongly-typed classes that are optimized for our specific view scenarios, and which expose properties for the dynamic values/content needed by our view templates. Our controller classes can then populate and pass these view-optimized classes to our view template to use. This enables type-safety, compile-time checking, and editor intellisense within view templates.

Taken from "Chapter 1 "Nerd Dinner" from Professional ASP.NET MVC 1.0 written by Rob Connery et al published by Wrox". The original is available at http://tinyurl.com/aspnetmvc