An ASP.NET file has an *.aspx extension. Typically, it contains HTML elements, server-side codes and client-side codes. As shown in Figure 3.4, when a user requests an ASPX page, the server retrieves it from the disk and then sends it to the ASPX Engine for further processing. The ASPX Engine compiles the server side codes and generates the page class file. It then instantiates the class file and executes the instructions to develop the response object. During the execution stage, the system follows the programmatic instructions (in the server-side code) to process the data submitted by the user. Finally, the server transmits the response object to the client. In short, the major steps in processing a request for an ASPX page are as follows:

1. The server receives a request for a desired ASPX page.

2. The server locates the page in the disk.

3. The server gives the page to the ASP.NET Engine.

4. The ASP.NET Engine compiles the page and generates the page class. If the class had already been loaded, it simply provides a thread to the running class instead of regenerating the class. During compilation, it may require other code classes, such as code-behind classes and component classes. These are assembled during this step.

5. The ASP.NET instantiates the class, performs necessary processing, and it generates the Response object.

6. The Web server then sends the Response object to the client.

Figure 3.4: Major Steps in Serving an ASPX Page

Now that we know about the...