4.1. The UI and Web Forms

Web Forms are the most common paradigm used to create ASP.NET pages. They’ve been available since version 1.0, and they’re based totally on an event-driven approach. The name recalls the characteristic of an ASP.NET page: to be composed of a maximum of one server form at a time. You can embed non-server forms at your discretion, but only one of them is the server form. You can also have a page that doesn’t have a server form. You need one only if you’re planning to include a server control that needs PostBack (or that explicitly requires it). (If all this sounds strange to you, take some time and review chapter 1).

Most developers use Web Forms to build the GUI in a web application. Even if you decide to opt for MVC (outlined in chapter 8), many of the ideas we’ll present here will still be valid. Remember, though, that the reason behind the success of ASP.NET is, without a doubt, Web Forms and their simplicity. ASP.NET MVC looks cool and promising (and it is), but it’s relatively new. Although the Web Form model is fully extensible, it’s not designed to be used in scenarios where you need 100% markup control or testability. In those cases, ASP.NET MVC is the better choice.