ASP.NET MVC – Where Is Model Data Stored?

asp.net-mvcasp.net-mvc-4mvc

I am using ViewModel classes in order to structure data being populated inside of a controller.

My questions is now where exactly is data of a @model stored after being populated via asp mvc controller.

Best Answer

In MVC, the model (that is an instance of a model class) is nothing more than an ordinary object. It is initialized by the controller which passes it to MVC's engine which, in turn, uses it when generating the final result from a view.

If you're asking whether it is stored on the stack or on the heap, the response is: on the heap.

Instance variables for a reference type are always on the heap.

If you're asking whether it is stored in memory or on a hard disk, the response is: it depends. In general, it will be in memory, unless the operating system runs out of memory and decides to move it to the pagefile (chances for this to happen are slim).

If you're asking how should you access the model once initialized (i.e. where to find the instance of the model class), just keep a reference to it within the controller itself.

Related Solutions

MVC Pattern, ViewModels, Location of conversion

I agree that you are doing it the right way. Jimmy Bogard (author of AutoMapper) wrote an excellent article on why this style of solution structure works and I follow this "guidance" whenever I can: http://www.lostechies.com/blogs/jimmy_bogard/archive/2009/12/08/organizing-asp-net-mvc-solutions.aspx

However you should also focus on getting the right structure within you Library assembly. Richard Dingwall wrote an interesting article on organizing your code by responsibility rather than technology: http://richarddingwall.name/2009/08/08/real-life-ddd-organise-code-by-responsibility-layers-not-repositories-and-services/

ASP.NET MVC – Role of ViewModels in MVC and 3-Tier Architecture

main MVC project, where M of MVC was moved to Data Access Layer

Common misconception. The M of MVC has nothing to do with data, despite the many examples and tutorials that claim so.

M is your ViewModel and should reside in your MVC project. The ViewModels you have in your BLL are actually to be named DataContracts or BusinessModels.

In your controller you have something comparable to this:

Get(id):
    dataContract = _service.Get(id);
    viewModel = Map(dataContract);
    return viewModel

In your service, something like this:

Get(id):
    dataModel = _dataAccess.Get(id);
    dataContract = Map(dataModel);
    return dataContract;

And in the DataAccess, you perform the proper joins according to the object requested. You are however of course free to add custom methods to your DataAccess when required, so your service can call those methods:

GetWithBars():
    dataModels = _repository.Query("select from foos join bars");
    return dataModels;

Best Answer

Related Solutions

MVC Pattern, ViewModels, Location of conversion

ASP.NET MVC – Role of ViewModels in MVC and 3-Tier Architecture

Related Topic