So far, all web pages we have created in our coding samples are based on the page controller pattern, which is the default architecture in the ASP.NET web forms. Let us understand page controller in detail.

In Chapter 2, we noticed that inline coding samples in ASP and ASP.NET had HTML and code scripts mixed together, creating a hard-to-maintain code base. Then we studied how code-behind classes "modularized" the architecture by separating the logic from the HTML. This code-behind architecture is a page controller based design, where by controller we mean the components that control the rendering of the HTML, which in the case of ASP.NET web forms are the code-behind classes.

Each page has a code-behind class, and the URL requested by the client is directly handled by individual pages. Any button or server control causing postbacks (such as a DropDownList control) is handled directly by the page code-behind class. So understanding the page life cycle is very...