10.6. Exploring ASP.NET Web Part Controls

The Toolbox task pane in SharePoint Designer hosts another set of ASP.Net 2.0 controls called Web part controls. These are generic controls that can be used to host custom Web part controls and server controls developed programmatically. The primary hosting controls offered in ASP.NET 2.0 for Web parts are:

• WebPartZone: This control acts as a placeholder control and hosts other server Web part controls and ASP.NET 2.0 controls.

• CatalogZone: A catalog is basically a list of Web part controls. The CatalogZone allows developers to create a list of Web parts that can be used to insert them on Web pages dynamically at browse time.

• EditorZone: This control acts as a host for a number of editor Web parts, such as AppearanceEditorPart, BehaviorEditorPart, LayoutEditorPart, and PropertyGridEditorPart. The editor Web parts can be used to design the editing interface of the Web part properties, which are displayed to the end user at browse time.

• ConnectionZone: The ASP.NET 2.0 ConnectionZone Web part allows developers to enable connections between Web parts at browse time. This means that end users visiting the Web sites can connect two or more Web parts together and then transfer data from one Web part to another.

Web part controls are different from other ASP.NET controls in that ASP.NET 2.0 provides the infrastructure to dynamically add, remove, and modify properties of Web part controls directly in a browser. This means that developers can use these controls to program Web site interfaces in such a way that the end user visiting a Web site can add or remove Web parts from a list of predefined Web part controls. This way, developers can offer enhanced control of the Web site interface to Web site users.

SharePoint extensively uses these Web part controls as well as controls inherited from these controls to implement its Web part functionality. ASP.NET 2.0 also forms the basis for the ability to add Web parts dynamically to Web pages at browse time, creating Web part connections, editing Web part properties, etc.