MSDN Magazine - March 2008 - (Page 52)

technologies. A future drop of the framework will be shipping with a WebFormsRouteHandler, and other technologies will be taking advantage of the generic routing system in the future. Controllers don’t have to derive from System.Web.Mvc.Controller. All a controller need do is implement the IController interface, which has only a single method called ExThe ASP.NET MVC ecute. From there you can Framework is a compelling do whatever you like. If complement to Web Forms you only want to tweak a few behaviors of the base for developers who want Controller class, on the complete control over their other hand, Controller has Web applications. many virtual functions you can override: • OnPreAction, OnPostAction, and OnError let you hook up generic pre- and post-processing on every action that gets executed. OnError gives you a controller-wide error handling mechanism. • HandleUnknownAction is called when a URL gets routed to the controller but that controller doesn’t implement the action requested in the route. By default, this method throws an exception, but you can override it to do anything you’d like. • InvokeAction is the method that figures out what action method to call and calls it. If you’d like to customize the process (for example, to get rid of the requirement for [ControllerAction] attributes), this is the place to do it. There are several more virtual methods on Controller, but they’re primarily there as testing hooks rather than as extension points. For example, RedirectToAction is virtual so that you can create a derived class that doesn’t actually redirect. This lets you test actions that redirect without needing a full Web server running. Farewell Web Forms? At this point you may be wondering, “What’s happening to Web Forms? Is MVC replacing it?” The answer is no! Web Forms is a well-understood technology, and Microsoft will continue to support and enhance it. There are many applications where Web Forms work very well; the typical intranet database reporting app, for instance, can be created using Web Forms in a fraction of the time it would take to write it in MVC. Plus Web Forms supports a vast marketplace of controls, many of which are extremely sophisticated and save massive amounts of work. So, when should you choose MVC over Web Forms? In many ways, it comes down to your requirements and your preferences. Are you struggling to get your URLs formed the way you want? Do you want to unit test your UI? Either of those scenarios would lean toward MVC. On the other hand, are you doing a lot of data display, with editable grids and fancy tree view controls? Then you’re probably better off with Web Forms for the moment. Over time, the MVC Framework will probably catch up in the UI control department, but most likely it’ll never be as easy to get started with as with Web Forms, where massive amounts of functionality are just a drag and drop away. But in the meantime, the ASP.NET MVC Framework offers Web developers a new way to build Web applications in the Microsoft .NET Framework. The Framework is designed for testability, embraces HTTP instead of trying to abstract it away, and is extensible at just about every point. It is a compelling complement to Web Forms for those developers who want complete control over their Web applications. ■ 52 msdnmagazine ASP.NET MVC

Table of Contents Feed for the Digital Edition of MSDN Magazine - March 2008

MSDN Magazine - March 2008 Contents Toolbox CLR Inside Out Data Points Advanced Basics Office Space Introducing ASP.NET MVC Loosen Up CI Server Performance Office Development Test Run Security Briefs Extreme ASP.NET Foundations .NET Matters {End Bracket}

MSDN Magazine - March 2008

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