Microsoft SharePoint provides a variety of ways to add custom code to enhance or customize the SharePoint experience. These include web parts, timer jobs, application pages, delegate controls, custom actions, and so on. Delegate controls provide numerous locations on each SharePoint master page where default controls may be replaced with specified custom controls. This allows for SharePoint to place different controls on the page based on the features that are activated. For instance, when publishing features are enabled, SharePoint will use the delegate controls to add the publishing controls to the page.

In addition to the delegate controls provided (and required) on each SharePoint master page, additional delegate controls can be added to custom master pages. In this chapter, however, we will stick to the ones provided by SharePoint. The commonly used delegate controls provided by SharePoint are listed in the following table: