Microsoft released the ASP.NET MVC Framework updates to CTP 2 in the middle of April and for those using it you may have noticed some changes to the way certain things are done. 

I am working on a project where I am using the CTP to get a web site built and learning ASP.NET MVC along the way.  I started using the CTP 2 for the project and moved over to the latest code drop as soon as it came out.  Sure, I expected some changes so it was not a big deal, but the ones I encountered were interesting and caused a little head scratching about something that worked before but not now.

Project Wizard

The CodePlex April 16 MVC Interim Source Code Release includes two downloads, the MVC code itself and a set of Visual Studio MVC Templates.  When I first saw the templates I figured they were just some additional ones but they are above and beyond those in the original CTP2.  You can see there are two templates now when creating a new project.

One is shown under Visual Studio installed templates, called ASP.NET MVC Web Application and the other one and newer is under My Templates and is also called ASP.NET MVC Web Application.  Choosing one over the other creates two very different sets of code.

One benefit of having two sets of templates is you can create applications for both sets of code bases, CTP2 and the interim drop.  One other thing that is different when using the new templates is you don’t get a nice test project to go in your solution.  It can be added of course.

Controllers

One of the changes which threw me off right away is the way Controller action methods have changed.  You can see from the screen shot just below that the controller action method Index() returns a void.

But the controller from the interim code drop controller action now returns an ActionResult, not a void.  This obviously breaks existing code.  Changing my existing code to work was not a big deal but was a surprise when trying the first build with the new code drop.

After fixing this code and heading over to Scott Guthrie’s blog, he explains the reasoning behind the changes:

The MVC feature team is experimenting with a few ideas in this week’s drop and are trying out some new ideas:

1. Action methods on Controllers now by default return an "ActionResult" object (instead of void).  This ActionResult object indicates the result from an action (a view to render, a URL to redirect to, another action/route to execute, etc). 

2. The RenderView(), RedirectToAction(), and Redirect() helper methods on the Controller base class now return typed ActionResult objects (which you can further manipulate or return back from action methods).

3. The RenderView() helper method can now be called without having to explicitly pass in the name of the view template to render.  When you omit the template name the RenderView() method will by default use the name of the action method as the name of the view template to render.  So calling "RenderView()" with no parameters inside the "About()" action method is now the same as explicitly writing "RenderView(‘About’)".

So why change Controller action methods to return ActionResult objects by default instead of returning void?  A number of other popular Web-MVC frameworks use the return object approach (including Django, Tapestry and others), and we found for ASP.NET MVC that it brought a few nice benefits.

Please take a look at Scott’s post on this to see all of the benefits which I won’t go into here.

Routing and Default.aspx

In the CTP2 release there is a default.aspx page that was really just a placeholder page that had no code-behind, but building with the new bits causes the default route to not behave the same way and produce a page not found error.  In order to fix this some code behind is added to default.aspx which fixes the problem for CTP2 code.  Below is what I added and incidentally is the same code added by the new templates.

The changes are needed because of helper method called routes.MapRoute() which eases the syntax of creating routes.  Anyone who created routes with routes.Add will understand how it can be a bit simpler:

The recent code drop (4/16) templates fix all these issues and new projects just work without having to deal with tweaking code.

Conclusion

I think these changes are keeping us on course in the right direction but are a couple of gotchas if you are not aware of them.

As an fan of all things MVC, today’s news of the release of the ASP.NET MVC Source Code was really good news.  I think it shows Microsoft’s continued steps toward being open source. 

Scott Guthrie was the one breaking the news and he has some details on his blog to check out.  The source was released as part of a CodePlex project and can be found as part of the ASP.NET CodePlex project, where the source can be found and downloaded.

Scott Hanselman also has a great post about his thoughts on the ASP.NET MVC source code and goes into some detail in The Weekly Source Code.  It’s really nice to see Scott spend the time pointing us to various areas of the source code.  It’s good stuff and worth the read.

In case you missed one of Scott’s earlier examination of the ASP.NET MVC Source you should also check it out.

The team providing us with the ASP.NET MVC Framework made available the 2nd preview release during the MIX08 Conference March 5-7, 2008 in Las Vegas, NV.  This release has many great changes as they team works toward an RTM maybe later in the year, but no promises were made.

I just wanted to point out some of the bigger changes in the Preview 2 release.

The ASP.NET MVC Framework can be deployed in the \bin directory of an app and work in partial trust

One of the pain-points in the current CTP of the ASP.NET MVC Framework is the framework is installed with a setup program to register it in the Global Assembly Cache (GAC), this is fine for local installations on development machines but not good when need to deploy to other systems.  Microsoft is fixing this:

Starting with this upcoming preview release we will enable applications to instead directly reference the System.Web.Mvc.dll assembly from the application’s \bin directory.  This means that no setup programs need to be run on a sever to use the ASP.NET MVC Framework – you can instead just copy your application onto a remote ASP.NET server and have it run (no registration or extra configuration steps required).

Requiring  System.Web.Mvc.dll to be in the GAC also made it unlikely to be able to use the MVC framework with shared hosting providers, the new CTP will also fix this potential problem as well:

We are also doing work to enable the ASP.NET MVC framework to run in “partial/medium trust” hosting scenarios.  This will enable you to use it with low-cost shared hosting accounts – without requiring the hosting provider to-do anything to enable it (just FTP your application up and and it will be good to run – they don’t need to install anything).

It’s unlikely anyone would have faced these issues yet, since the MVC is so new, but good to know it was thought out in advance.

Significantly enhanced routing features and infrastructure

URL routing is one of the most powerful features of the MVC framework, letting developers have infinite control over the structure of the URL’s in their applications. 

This upcoming ASP.NET MVC preview release contains even more URL routing features and enhancements.  You can now use named routes (enabling explicit referencing of route rules), use flexible routing wildcard rules (enabling custom CMS based urls), and derive and declare custom route rules (enabling scenarios like REST resources mappings, etc).

We have also factored out the URL routing infrastructure from the rest of the MVC framework with this preview, which enables us to use it for other non-MVC features in ASP.NET (including ASP.NET Dynamic Data and ASP.NET Web Forms).

Improved VS 2008 Tool Support

The initial release of the MVC framework shipped with some useful but simple templates for web projects but improvements are coming:

This upcoming ASP.NET MVC preview release will ship with improved VS 2008 integration.  This includes better project item templates, automatic project default settings, etc.  We are also adding a built-in “Test Framework” wizard that will automatically run when you create a new ASP.NET MVC Project via the File->New Project dialog.  This will enable you to easily name and wire-up a unit test project for your ASP.NET MVC application.

The Test Framework wizard will allow the developer to choose from a list of available unit testing frameworks but is pluggable to allow for additional testing frameworks to be added.

[ControllerAction] Attribute No Longer Required on Controller Action Methods

The first MVC framework required developers to use the [ControllerAction] attribute to distinguish action methods on a controller in order for it to be callable from an application.  Due to developer feedback the new release will do away with this requirement and make all public methods defined on a controller to be action methods and therefore callable.

There will be attributes available to use to make a public method a non-action method.

New Filter Attribute Support for Controllers and Action Methods

A new feature being added to the release are Filter Attributes.  Basically, these attributes are actions a developer may want to execute either before or after a controller or its action executes.

These enable you to inject code interceptors into the request of a MVC controller that can execute before and after a Controller or its Action methods execute.  This capability enables some nice encapsulation scenarios where you can package-up and re-use functionality in a clean declarative way.

HTML Helpers Built-in

Helper methods were limited in the first release of the framework, where a separate download was made available which included a bunch of HTML helper methods.  The new release will have all of the optional helper methods built-in.  Future framework updates will include ASP.NET AJAX support:

Next month we are also going to start to talk about some of the new enhancements to the client-side ASP.NET AJAX libraries we are making, as well as some of the AJAX helper methods we will build to enable it to easily integrate with ASP.NET MVC.

These were the HTML helper methods developed by Rob Conery.

Lots of Refactoring and Design Improvements

As with any public CTP of a product, the idea is to iterate and evolve the product into something people will use.  The team is making design improvements to the existing code base to allow for better extensibility.

In general the team has followed a philosophy where for all features you have three options:

1. Use the built-in features/implementations “as-is” out of the box
2. Slightly customize the built-in features/implementations without having to write much code
3. Completely swap out the built-in features/implementations for custom ones

For example: you can now override the ViewEngine locator logic without having to override the ViewEngine execution logic (and vice-versa) – or alternatively swap out ViewEngines entirely.  The Controller Factory support has been extended to make it even easier to integrated with dependency injection frameworks.  Route rules are now fully extensible.  Controllers are more easily testable, etc.

This type of flexibility gives developers choices, not forcing them into doing things a certain way which can help improve the ability for developers to more quickly adopt the framework.

Downloadable ASP.NET MVC Framework Source that can be Built and Patched

Following the lead of downloadable .NET Framework source code, the team will be making the source code for the MVC framework available with the same methods.

Starting with this next preview, we are also going to make the ASP.NET MVC Framework source code downloadable as a buildable VS project solution.  This will enable you to easily view and debug the ASP.NET MVC Framework source code.  We are also going to include a license that permits you to optionally make patches to the ASP.NET MVC Framework source code in the event that you run into a bug in an application you are developing with it.

The license won’t enable you to redistribute your patched version of ASP.NET MVC (we want to avoid having multiple incompatible ASP.NET MVC versions floating around and colliding with each other).  But it will enable developers who want to get started building ASP.NET MVC applications immediately to make progress – and not have to w
orry about getting blocked by an interim bug that they can’t work around.

Screencasts Showing-off Features

Scott Hanselman has put out some great screencasts to show off how the ASP.NET MVC works in its current iteration.  At the time I write this there are 4 screencasts available showing increased complexity while working on the same sample code base.

• Part 1 – Displaying Data
• Part 2 – Editing Data and Making Forms
• Part 3 – Advanced Techniques
• Part 4 – Testing

Also available is Scott’s session at MIX08

Developing ASP.NET Applications Using the Model View Controller Pattern

I have taken the time to work with this Preview 2 of the ASP.NET MVC Framework and developed some simple applications, which worked wonderful.  My experience with Ruby on Rails really helps in understanding this framework.  Comparing the first CTP to this one is really a night and day difference, in my opinion.  I am looking forward to future releases and building real applications this way on .NET.

Rob Conery’s recent post, Ramble: ASP.NET MVC Is A Geek Chisel started me thinking again about the Microsoft ASP.NET MVC Framework.  I develop software targeting the .NET framework as well as Ruby web applications using Ruby on Rails.   The .NET applications I manage have clients ranging from small shops to enterprise-wide complex pieces of software.  When I have a choice, I choose Ruby on Rails.  Why?  Because it is so much simpler to turn out software fast.

I have not given much thought to the MVC Framework lately after watching Scott Hanselman’s screencast on its usage.  No offense to Scott but the video left a really bad taste in my mouth.  I saw too much of the overly cumbersome things ASP.NET developers have to go through to make things line up.  Sure, you can drop a few controls on a page, hook up a database and wire-up your data bound controls, but that is not a realistic approach.

As most developers know, Microsoft has released an early CTP of the Microsoft ASP.NET MVC Framework which implements the Model-View-Controller pattern, the same pattern implemented by Ruby on Rails.

Rob’s post can be summed up here:

Chiseling a Digital David
While I was in Redmond last week I discussed this very thing (?the story? behind MVC and why it?s appealing) close to 12 times. I kept struggling with analogies and I think I found one that works for me. It might not work for you – but I?m sincerely interested to hear what you have to say in this arena. Believe me – it?s important!

As a developer you build things- just like any contractor building a house, or artist creating a work of art. Often times artists will choose not to use tools that save them time, preferring to build something that they can (literally) work with their hands so they can ?feel the art inside the medium?.

In the same way that Big Z showed Cody how to shape a board (?looong, easy strokes?) – many people just want the machinery to get out of their way when building a web site so they can create their HTML how THEY want to, and use JavaScript and form tags as they see fit.

Some people see this as tedious, repetitive work – others see the process as creationary and artistic. I think they?re both right and I love how ASP, now, supports both.

I was in the conversation Scott referenced in his post about implementing a Repeater in MVC:

We need to come up with a Repeater control for folks using MVC?

We have a Repeater – it?s called a For Loop

I want to share who said that line but I?ll keep it close to my chest since it was said behind a closed door ;).

What Do You Think?
Part of my gig with Microsoft is soliciting as much community feedback as I can. I tend to believe that ASP.NET MVC allows for much more ?hands-on? type of development with extreme control over your UI (HTML/JavaScript) that allows you to create some really cool work.

Do you agree with this? If not – what?s the appeal for you? Does it frustrate you to have so many choices and if so – how can we help to provide some guidance?

I would like the ASP.NET MVC Framework to provide the ease of application creation just like Ruby on Rails.  I use Ruby on Rails often and the framework makes the life of the developer so much easier.  The key requirements for me are:

• One of the most important aspects of Ruby on Rails to me is it’s ability to create web applications fast.  Prototyping is necessary to help aid clients or even other developers understand the interpretation of the business requirements.  It is much better to find out up-front the ideas are wrong before spending too much time coding.  Today this is difficult using ASP.NET WebForms.
• SubSonic is great tool, integrate it in the framework but make the integration and usage dead easy.  Rails usage of ActiveRecord is very simple and is not something developers have to pay much attention to.  Creating Migrations, running them and then having the frame “just know” about them is great. 
• Let me write my migrations and configuration files in my language of choice, C#, VB.NET or whatever. 
• Give developers drop-dead-simple to powerful features like Scaffolding which makes creating back-end data management applications almost instantaneous and take the pain of this necessary evil.
• Give me a default configuration so I just start pumping out new models, controllers, scaffolding or what ever I might need.   Command line or a right-click in Visual Studio’s Solution Explorer.
• Make all view engines first-class citizens, easy integration and usage.
• Make all back-end ORM toolkits first-class citizens; if SubSonic, NHibernate or some other ORM, make it just work with extensive configuration.

Powerful frameworks without a simple and default implementation lead to slow adoption.  It has taken most developers many years of dedicated development to pick up ASP.NET Web Forms and consider themselves experts on using it.  These developers won’t jump ship and just start using the MVC Framework if this framework has the complexities of web forms.  Ruby on Rails gives developers a default implementation, makes decisions for them so they can use the framework immediately out-of-the-box but provides great depth so it can be overridden and harness the great power of the underlying framework.  The key here is the canned or out-of-the-box implementation used as a catalyst to allow developers to create prototypes very quickly.

So, if Microsoft is looking for a story for the MVC Framework, make it drop-dead easy to create web applications.  Don’t make me work any harder than I do to create a Ruby on Rails applications and give me all the same tools the Rails team gives its developers.  I don’t really think I need to be pointing this out, it should be as obvious to other developers as it is to me.  I guess maybe not if you never used Rails before.

The moment has finally arrived, Microsoft released their first CTP of the MVC Framework.  I am very anxious to get some time to start working with the bits they are releasing today.

I plan to get heavily into this framework and will post some tidbits of how it works, but in the meantime here are links to some interesting content from some people who know about the MVC Framework.

Scott Guthrie has a couple nice posts on using the framework from the past couple weeks:

• ASP.NET MVC Framework (Part 1)
• ASP.NET MVC Framework (Part 2): URL Routing
• ASP.NET MVC Framework (Part 3): Passing ViewData from Controllers to Views
• ASP.NET MVC Framework (Part 4): Handling Form Edit and Post Scenarios
• ScottGu MVC Presentation and ScottHa Screencast from ALT.NET Conference

Rob Conery, who joined Microsoft recently, also posted about his work on the MVC team:

• ASP.NET MVC Preview: Using The MVC UI Helpers
• ASP.NET MVC: Using RESTful Architecture

Jeffery Palermo has been active working on the framework:

• ASP.NET MVC and the Future of Model View Presenter : Interview with Jeffery Palermo
• Use the ASP.NET MVC Framework to Write Web Apps without Viewstate or Postbacks from Code Magazine

Rick Strahl provides some insight about his take on the MVC Framework:

• What’s Ailing ASP.NET Web Forms

Phil Haack was also recently hired by Microsoft and post some interesting MVC related items:

• TDD and Dependency Injection with ASP.NET MVC
• Extending ASP.NET MVC To Add Conventions

Microsoft has started an open source project on CodePlex for those wanting to contribute to the ASP.NET MVC Framework, called MVC Contrib.  Also, to get everyone started are some Quickstarts.

UPDATE: Thanks to Jeffrey Palermo for setting me straight, the MVC Contrib project was started by Jeffrey and Eric Hexter.  It is a project independent of Microsoft.

The talk in the blogs about the Microsoft ASP.NET MVC is gaining momentum and some interesting chatter is coming to the surface.

I posted my thoughts about the framework recently and came across a post by Scott Watermasysk as well, with his views in line with mine.  I found an interesting post today from Ken Egozi, who writes a view engine for MonoRail.  Ken plans on duplicating the effort put forth by Scott Guthrie who is creating a sample application using ASP.NET MVC Framework, but Ken will be using MonoRail and ASPView.

Ken has some great points about the adoption of the ASP.NET MVC Framework requiring .NET 3.5, where so many web hosts and companies support version 2.0 of the runtime and will they be willing to upgrade.   Ken’s solution can be run on .NET 2.0 today.

I am looking forward to comparing the results.   The types of challenges are what makes competition good for all developers and can only help make MonoRail/ASPView and the ASP.NET MVC Framework better for it.

I have been an ASP.NET developer for a few years now and have used it successfully on many projects.  I never really liked Webforms from the perspective of good architecture with separation of concerns but it has been the generally accepted way to develop web application with ASP.NET.  Yes, I know about MonoRail now but it wasn’t a technology I was aware of back in the ASP.NET 1.0 days.

Much of my work on projects these days is from an architecture and technical lead role so I get to work with new technologies to see how they may best-fit into an application or environment.   I discovered Ruby on Rails about a year and half ago and was really awed by MVC pattern usage in the framework.   The MVC framework was not developed by 37Signals but they surely made it popular in today’s web development arena.

Today I write applications both in Ruby on Rails and ASP.NET C#, both have their strengths and weaknesses.   The single greatest feature from an architecture perspective, in my opinion, is the implementation of the MVC.  The greatest news I have heard coming from Redmond was the addition of an ASP.NET framework for MVC coming after Visual Studio 2008 is released.

First Look

The first opportunity I had to see the new ASP.NET MVC Framework was the presentation at ALT.NET by Scott Guthrie.  It seemed like Scott and his team had done their homework and produced something we could work with.

Scott Guthrie gives a very nice write-up on his blog on what we can expect in this new framework.  He says all the right things here:

• Separation of concerns
• Test-Driven Development (TDD)
• Highly Extensible and Pluggable
• URL Mapping to SEO and REST-friendly naming

These are things that make Rails very powerful and some of the things I really love about Rails.

It makes one wonder what we might be giving up, the ASP.NET MVC Framework is going to allow ASP.NET to keep the things that make using the rich framework pleasant.   The ASP.NET MVC Framework supports:

• ASP.NET .ASPX and .ASCX and .Master as “View” templates.
• Forms/windows authentication, URL authorization, membership/roles, output and data caching, session/profile state management, health monitoring, configuration system and the provider architecture.
• We lose the post-back model (yah), actions are routed to a controller instead.

Best of Both Worlds

The ASP.NET MVC Framework is still some time off but the information released so far should make it easier for developers such as myself who write Rails applications but also write ASP.NET applications.  As an architect I can use my favorite web design pattern and use it on two platforms, giving me choice.

It will be easier becoming an expert on a pattern such as MVC and apply it to both Rails and now…ASP.NET.  This will be very good.

Mads Kristensen had an interesting post about the Dangers of the ASP.NET MVC Framework.  Mads states the introduction of the MVC Framework could divide the development community in a negative way.  I agree the community may split a bit but I don’t think it will be a bad thing as those entrenched in ASP.NET Webforms will continue to use them.  I will continue to use them for existing applications already running on a code base committed to Webforms.  There will be people who move to MVC either because they have used Rails or MonoRail and want to give it a try or are curious about the whole hoopla about MVC.  Webforms has a solid base and will be improved and supported, Microsoft just sees an opportunity here and is taking advantage of it for the better of ASP.NET.

The Result

So who knows where this journey will take us but I know Microsoft is not stupid and they follow what is popular and working well.  I think Rails and Monorail had great influence in creating this framework.

The framework is getting closer to being released as a CTP, as evidenced by Scott Guthrie’s great example on creating a website using the framework, part 1 of many.  I don’t know how he finds time to produce such great content but he does.

My hope is being able to have one architecture (MVC) but have two frameworks, Rails and ASP.NET MVC to chose from to solve my client problems.  I think Microsoft has taken the right approach and my hopes will be realized.