ASP.NET Custom Server Controls Content Map
This section includes topics that show you how to create custom ASP.NET web server controls. The topics provide information and code examples that illustrate different control-authoring tasks such as rendering, defining properties, managing state, and creating composite controls.
Adding AJAX functionality to ASP.NET server controls
The following resource provides additional information about how to create custom web server controls.
This blog post explains coding techniques that make sure custom controls install and run correctly in web site projects, in web application projects, and in the toolbox.