The most obvious change in the internal workings of ASP.NET 2.0 relates to how an ASP.NET Web page is created. In this section, we will examine the changes to the code-behind model and how these changes impact ASP.NET development.

In ASP.NET 1.x, developers had two primary options for developing a Web Form. First, the developer could follow the traditional ASP model and write code directly in the ASPX page. This process, known as code-inline, works very well for simple commands. However, for more complex code, writing code-inline results in difficult to read Web pages that mix presentation (HTML) with functionality (code).

In ASP.NET, the default coding practice was changed to help solve this problem. Business logic and event-handling code could be written in a separate, code-only file known as the code-behind file. The code-behind model links a code-only file with the ASPX file that contains presentation tags. By separating the code from the presentation, development teams could work faster by allowing the designers to work on the presentation file while the developers worked on the code file.