Gridview Update

Question

Please, friends I have two related tables-Projects and Project Type Tables. I have used inner join to show data from both tables in a gridview in asp.net page and also written an update, insert, delete stored procedures for them all these is working fine. The Project Type is a foreign key in Projects Table. I want to edit the Project Type in Projects table using a Dropdownlist in gridview. Please any idea on how to go about will be highly appreciated. Thanks.