c# - where clause in entityDataSource with field from other table entity -

i've got 3 tables, products, productspercategory , category. can choose category, after products category listed.

but cannot seem work.

i using entity framework, have created 2 entitydatasources, 1 products , 1 productspercategory. i've got id category in variable in code.

i have added parameter productspercategory entitydatasource.

 <whereparameters>                 <asp:controlparameter controlid="categoryid" name="category_id" propertyname="value" />  </whereparameters>

but need add parameter products entitydatasource show products in productspercategory entitydatasource. how can this?

database structure:

category table contains: name, categoryid productspercategory table contains: id, categoryid, productid product table contains: productid, name

so want product names in entitydatasource belong selected categoryid

i solved using sqldatasource

KHS