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The Provider web part pushes out the parameter and the Consumer web part is set up to receive and consume the consume the parameter information.
Interface file: Defines the data to be shared from the Provider to the Consumer web part.
Provider web part:
a. Inherits from Microsoft.SharePoint.WebPartPages.WebPart
b. Implements a data interface – this interface is a definition of the data that will be shared from the Provider web part to the Consumer web part.
c. Provide mechanisms for user selection of the interfacing data
d. Provide a ConnectionProvider method which will expose the interfacing data to the Consumer web part.
Step 1 – Create visual web part solution