Chapter 8. Custom Controls

At its core , ASP.NET is a control-based architecture, defined in the following way:

• A Page is a control.

• Any control may contain child controls.

• A control is rendered by rendering its contents and then iteratively rendering its children.

This architecture is analogous to the window architecture in the Win32 API. The desktop itself is a window (like the Page ), and any window may contain child windows . Each window is rendered by first rendering its contents and then rendering the contents of its children. The rendering of a window on the desktop involves drawing pixels to a display, whereas the rendering of an ASP.NET control involves generating HTML to populate a portion of the response to an HTTP request. ASP.NET's control architecture is a completely extensible framework, and in this chapter, we look at techniques for building custom controls to create truly reusable Web components that encapsulate details of presentation and server interaction.