Understanding the ASP.NET MVC Execution Process
Learn how the ASP.NET MVC framework processes a browser request step-by-step.
Requests to an ASP.NET MVC-based Web application first pass through
the UrlRoutingModule object, which is an HTTP module. This module
parses the request and performs route selection. The UrlRoutingModule
object selects the first route object that matches the current request.
(A route object is a class that implements RouteBase, and is
typically an instance of the Route class.) If no routes match,
the UrlRoutingModule object does nothing and lets the request
fall back to the regular ASP.NET or IIS request processing.
From the selected Route object, the UrlRoutingModule object obtains the IRouteHandler object that is associated with the Route object. Typically, in an MVC application, this will be an instance of MvcRouteHandler. The IRouteHandler instance creates an IHttpHandler object and passes it the IHttpContext object. By default, the IHttpHandler instance for MVC is the MvcHandler object. The MvcHandler object then selects the controller that will ultimately handle the request.
|When an ASP.NET MVC Web application runs in IIS 7.0, no file name extension is required for MVC projects. However, in IIS 6.0, the handler requires that you map the .mvc file name extension to the ASP.NET ISAPI DLL.|
The module and handler are the entry points to the ASP.NET MVC framework. They perform the following actions:
- Select the appropriate controller in an MVC Web application.
- Obtain a specific controller instance.
- Call the controller s Execute method.
The following table lists the stages of execution for an MVC Web project.