What's better approach when creating a user control: receive a full object or only the needed values?

Question

I'm working with ASP.NET Web User Control (WUC) and I got to this question:

I'm creating a WUC to show an object's data. This object is already loaded when I call that WUC. I'm wondering what would be better: give the WUC the full object or only the necessary attributes?

Answer 1

If the UC is responsible for displaying the entire object, and only that object (not other objects) then it should be passed an instance of it, or a base class/interface of it.

If the UC is meant to be more general, though, or only displays a couple properties, you might just expose members for those specific properties.

Answer 2

Pass the full object, as long as the user control should "know of" its existence (separation of concerns). If the class for the object ever changes, you will only need to modify the user control internally, not how it is invoked.

Answer 3

Most controls will do just fine with the object itself. If you want to shield yourself a bit, create an interface which the object inherits, then pass the object as that interface to the UC. That way, you can change replace the object later and the UC won't care, because it only knows about the pieces in the interface.

You really don't want to pass individual properties unless it's only 1 or 2. Otherwise, you end up with functions that have a large number of parameters, or long lists of object initialization lines. Pass an object or an interface - things will be much cleaner.