Sharepoint: Developing Web Parts with the ICellProvider Interface
An ICellProvider Interface Web Part connects to a developed Web Part using an ICellConsumer interface. An ICellProvider interface should only be used to provide a single value to a Web Part developed from an ICellConsumer interface. There is no transformer available when an ICellProvider interface Web Part connects with an ICellConsumer Web Part. It's a direct connection between the provider and consumer Web Parts.
Please refer to "Connectable Web Parts in SharePoint Portal Server 2003" for more details regarding Connection Interfaces in SharePoint architecture.
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