title: Entity framework add a where clause to all queries
body: <p>I am using Entity framework 5 and using repository pattern. Say I got these entities Customer, Files, Images, Tasks, Invoice, User. </p>
  
  <p>Each entity (apart from Customer) has a foreign key of Customer. When a user logs in I store the customerid in session (aps.net mvc). What I want is any CRUD taken on all entities to be limited to the customer who's user is logged in. e.g I can't afford to delete a Task belonging to customer 1 to be deleted by user who is from customer 2. </p>
  
  <p>Is adding an argument of customerid for each method of repositories the best way to achieve this or are there any better/clever ways of doing it?</p>