What Is ASP.Net MVC?

Question

When I first heard about StackOverflow, and heard that it was being built in ASP.Net MVC, I was a little confused. I thought ASP.Net was always an example of an MVC architecture. You have the .aspx page that provides the view, the .aspx.vb page that provides the controller, and you can create another class to be the model. The process for using MVC in ASP.Net is described in this Microsoft article.

So my question is. What Does ASP.Net MVC provide that you wouldn't be able to do with regular ASP.Net (even as far back as ASP.Net 1.1)? It is just fancy URLs? Is it just for bragging rights for MS to be able to compare themselves with new technologies like Ruby On Rails, and say, "We can do that too"? Is there something more that ASP.Net MVC actually provides, rather than a couple extra templates in the File->New menu?

I'm probably sounding really skeptical and negative right now, so I'll just stop. But I really want to know what ASP.Net MVC actually provides. Also, if anybody can tell me why it's Model-View-Controller and not in order of the layers of View-Controller-Model or Model-Control-View depending on whether you are going top to bottom, or vice versa, I'd really appreciate that too.

EDIT

Also, it's probably worth pointing out that I've never really cared for the web forms (AKA server controls) model either. I've only used it minimally, and never on the job.

Answer 1

ASP.Net with it's code behind is almost MVC - but not - the one big thing that makes it not is that the codebehinds are tied directly to the aspx's - which is a big component of MVC. If you are thinking of the codebehinds as the controller - the should be completely decoupled from the view. The new .NET MVC rounds this out - and brings a complete MVC framework. Though there are existing ones for .NET already (see Spring.NET).

Answer 2

.aspx doesn't fulfill the MVC pattern because the aspx page (the 'view') is called before the code behind (the 'controller').

This means that the controller has a 'hard dependency' on the view, which is very much against MVC principles.

One of the core benefits of MVC is that it allows you to test your controller (which contains a lot of logic) without instantiating a real view. You simply can't do this in the .aspx world.

Testing the controller all by itself is much faster than having to instantiate an entire asp.net pipeline (application, request, response, view state, session state etc).

Answer 3

Primarily, it makes it very easy to create testable websites with well defined separations of responsibility. Its also much easier to create valid XHTML UIs using the new MVC framework.

I've used the 2nd CTP (I think they're on five now) to start work on a website and, having created a few web applications before, I have to say its hundreds of times better than using the server control model.

Server controls are fine when you don't know what you're doing. As you start to learn about how web applications should function, you start fighting them. Eventually, you have to write your own to get past the shortcomings of current controls. Its at this point where the MVC starts to shine. And that's not even considering the testability of your website...

Answer 4

The most common and known model of ASP.NET is (still) the Web Forms model, which is more similar to a event-driven model of making a web app, by using "Web Components", and handling events on them. Not really MVC at all.

ASP.NET MVC is a very different beast. I don't know the nitty gritty details of it, but I know it's more related to frameworks like Ruby on Rails. It hasn't really an 1.0 release yet, but it's usable.

Answer 5

Great article by Dino Esposito that is meant to explain ASP.net MVC to ASP.net webforms developpers:

http://dotnetslackers.com/articles/aspnet/AnArchitecturalViewOfTheASPNETMVCFramework.aspx

Answer 6

I looked through a couple simple examples such as this one. I can kind of see the difference. However, I don't really see how MVC uncouples the view from the controller. The view still references stuff that's in the controller. I do see how it makes it much easier to test, and that at least in MVC the controller doesn't have any knowledge of the view. And you wouldn't have to process the view to call methods in the controller. I can see that's quite a leap, even though at first glance it may not seem like much.

I do agree with @Will about fighting server controls. I've never worked in a situation where they were actually used, but many people I know who have, have run into quite a few limitations with them.

Answer 7

No more auto-generated html IDs!!! Anyone doing any sort of javascript appreciates this fact.

Answer 8

Article about ASP.net MVC Vs ASP.net Web form

http://weblogs.asp.net/shijuvarghese/archive/2008/07/09/asp-net-mvc-vs-asp-net-web-form.aspx

Answer 9

Scott Guthrie explained it in this post "ASP.NET MVC Framework"

• It enables clean separation of concerns, testability, and TDD by default. All core contracts within the MVC framework are interface based and easily mockable (it includes interface based IHttpRequest/IHttpResponse intrinsics). You can unit test the application without having to run the Controllers within an ASP.NET process (making unit testing fast). You can use any unit testing framework you want to-do this testing (including NUnit, MBUnit, MS Test, etc).

• It is highly extensible and pluggable. Everything in the MVC framework is designed so that it can be easily replaced/customized (for example: you can optionally plug-in your own view engine, routing policy, parameter serialization, etc). It also supports using existing dependency injection and IOC container models (Windsor, Spring.Net, NHibernate, etc).

• It includes a very powerful URL mapping component that enables you to build applications with clean URLs. URLs do not need to have extensions within them, and are designed to easily support SEO and REST-friendly naming patterns. For example, I could easily map the /products/edit/4 URL to the "Edit" action of the ProductsController class in my project above, or map the /Blogs/scottgu/10-10-2007/SomeTopic/ URL to a "DisplayPost" action of a BlogEngineController class.

• The MVC framework supports using the existing ASP.NET .ASPX, .ASCX, and .Master markup files as "view templates" (meaning you can easily use existing ASP.NET features like nested master pages, <%= %> snippets, declarative server controls, templates, data-binding, localization, etc). It does not, however, use the existing post-back model for interactions back to the server. Instead, you'll route all end-user interactions to a Controller class instead - which helps ensure clean separation of concerns and testability (it also means no viewstate or page lifecycle with MVC based views).

• The ASP.NET MVC framework fully supports existing ASP.NET features like forms/windows authentication, URL authorization, membership/roles, output and data caching, session/profile state management, health monitoring, configuration system, the provider architecture, etc.