CODEWITHSUNDEEP
asp.net-mvcasp.net-mvc-3model-view-controllerviewmodel
Kamyar
Kamyar

Reputation: 18797

Developing ASP.NET MVC web applications the right way

I'm starting to develop a new ASP.NET MVC application, and I'd like to make sure that my understanding about the way of developing applications under MVC pattern is correct.

Question 1: Suppose that I have some main views (MainView1, MainView2, ...) with some partial views in it (PartialView1, PartialView2, PartialView3, ...). From what I have understood about MVC, I should define a Model for each view. e.g. I have to define PartialModel, PartialModel2, ... and also define my main models which are containers of the partial models which have been used in them: 

public class MainModel1
{
    public PartialModel1 Partial1 {get;set}        
    public PartialModel2 Partial2 {get;set}
    public PartialModel3 Partial3 {get;set}
}

This way when I want to redirect to MainView, I can initialize the models used in that view by using this Model. Is my understanding of MVC correct? Or should communication between Views and Models be in another form in MVC?

Question 2: If the above is correct, Then suppose I have a partial view in some of my main view pages. This partial view has a submit button which calls an action method. This action method should somehow return the main page's view with the right viewmodels for views. Is there any recommendation about how to get/set viewmodels of other views in a partial view's action?

Thanks.

Upvotes: 1

Views: 375

Answers (2)

Pankaj Upadhyay
Pankaj Upadhyay

Reputation: 13574

Your understanding is perfectly fine. This is what you can also refer to ViewModel in Asp.net MVC.

So, What basically is an Asp.net MVC ViewModel ?

In ASP.NET MVC, ViewModels allow you to shape multiple entities from one or more data models or sources into a single object, optimized for consumption and rendering by the view. The below image illustrates the concept of a ViewModel:

enter image description here

The purpose of a ViewModel is for the view to have a single object to render, alleviating the need for UI logic code in the view that would otherwise be necessary. This means the only responsibility, or concern, of the view is to render that single ViewModel object, aiding in a cleaner separation of concerns (SoC). Concerns are distinct aspects of the application that have a particular purpose (i.e., concern), and keeping these aspects apart means your application is more organized, and the code more focused. Putting data manipulation code in its own location away from the view and controller, enforces SoC.

Using ViewModels in MVC for finer granularity and better SoC leads to more easily maintainable and testable code. Remember, unit testing is about testing small units.

Along with better coding practices, there are many business reasons demonstrating why you might consider using ViewModels:

  • Incorporating dropdown lists of lookup data into a related entity
  • Master-detail records view
  • Pagination: combining actual data and paging information
  • Components like a shopping cart or user profile widget
  • Dashboards, with multiple sources of disparate data
  • Reports, often with aggregate data

Upvotes: 1

Darin Dimitrov
Darin Dimitrov

Reputation: 1038710

You understanding is correct. Each view (no matter whether it is main or partial) should have a corresponding view model (unless in the very rare case where this view contains only static html of course). And following this logic a main view that has to render other partial views will have a view model which itself will have reference (maybe as properties) to view models that are required by those partial views.

There is another technique which is using the Html.Action helper. In this case the partial is rendered through another controller/action than the main one. So you don't need to reference the partial view model in the main view model. They will be completely distinct. Take a look at the following blog post to learn more about Html.Action.

Upvotes: 2

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