I just started using SP 2010, I need to implement a process using SP, so I created a parent/child list, and modify the dispform of the parent list to add child list as a web part to it. The problem is now when I click an item in the parent list, all the item of child list is displayed to the item. But I just want the item of child list with the same look up value of the item to be displayed. For example, the item in parent list has a ID of 2, I want only the item with ID 2 in the child list to be displayed when I open the parent item. Is there any good approaches to achieve the function?