Essential SharePoint

Connecting Parts

A web part that can exchange data with another web part is called connectable. You create a connectable part by implementing one of the SharePoint connection interfaces in your web part class. Since there are two sides to any connection, there are two interfaces for each type of connection: a provider and a consumer. The interfaces are described in Table 9-5.

Table 9-5. Web part connection interfaces

Interface pair	Use to share	Example
ICellProvider, ICellConsumer	Single item	Form web part (cell provider), Image web part (cell consumer)
IRowProvider, IRowConsumer	Row of values	List web part (row provider)
IListProvider, IListConsumer	List (table) of values	List web part (list provider)
IFilterProvider, IFilterConsumer	A list filter	Form web part (filter provider)
IParametersInProvider, IParametersInConsumer	Set of values as described by the web part	None
IParametersOutProvider, IParametersOutConsumer	Set of values as described by the web part	None

Creating a Simple Connection

The Web Part Templates for Visual Studio includes templates for ICellProvider and ICellConsumer web parts. To add connectable web parts to an existing web part library project:

1. In Visual Studio, choose Project → Add → New Item and select the Provider Web Part template.

2. Create a .dwp file for the web part.

3. Repeat for the the Consumer Web Part template.

4. Build the project.

5. Create a test web page and import the two web parts onto the page.

6. Choose Modify Shared Page ...