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Correct use of Model vs Controller in MVC / ASP.NET MVC

Asked 2011-08-10T20:48:03.790
30

I have a Service class with a method called GetProducts(). That encapsulates business logic and calls the repository to get a list of products.

My MVC view wants to show that list of products as an MVC SelectList. Where is the correct place for that logic to go. I seem to have 3 options:

  1. Model

    The Model should expose a property called ProductSelectList. When the getter of this property is called by the View, the Model should call Service.GetProducts() and convert the result to a SelectList before passing it on.

    Plausible argument: The Model should make calls to business logic and the repository. The View should merely render predetermined data. The Controller should not be involved, save for passing contextual data to the Model.

  2. View

    The View should contain code that calls Service.GetProducts() directly and converts the result to a SelectList inline.

    Plausible argument: The View should call for this data directly as it is specifically for use on the View. There is no need to involve the Model or Controller, as we are calling an abstracted Service method anyway, so anything else just adds extra overhead.

  3. Controller

    The Controller should make the call to Service.GetProducts(), convert the results to a SelectList and pass it through to the Model, which should contain a simple ProductSelectList property. The View will access this property for rendering.

    Plausible argument: The Controller knows which parameters to provide to the Service method, so it should make the call. The Model should be a simple placeholder for data, filled by the Controller. The View's job is to simply render the data from the Model.

I have a feeling that the correct answer is Model, but the other two make

asp.net-mvc model-view-controller
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You're right that there are a number of ways to handle this, and that's even before considering variations like MVP, MVVM, et cetera. Since you're asking about ASP.Net MVC in particular, I will defer to Microsoft:

An MVC model contains all of your application logic that is not contained in a view or a controller. The model should contain all of your application business logic, validation logic, and database access logic. For example, if you are using the Microsoft Entity Framework to access your database, then you would create your Entity Framework classes (your .edmx file) in the Models folder.

A view should contain only logic related to generating the user interface. A controller should only contain the bare minimum of logic required to return the right view or redirect the user to another action (flow control). Everything else should be contained in the model.

In general, you should strive for fat models and skinny controllers. Your controller methods should contain only a few lines of code. If a controller action gets too fat, then you should consider moving the logic out to a new class in the Models folder.

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I would say your call belongs in the Model.

answered 2011-08-10T21:43:21.133

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