Implementing MVC in Winforms

I agree with pm100 in that there has to be a publish/subscribe mechanism.

In order to observe the 'separation of concerns' principle, the form (or view if you will), should define a number of events, of which your controller (or presenter in MVP) can hook up to.

If in the left pane you change selection, this will trigger the 'LeftPane_SelectionChanged' event which the controller is hooked up to and acts on, in this case obtaining the details of the selected item (which can be passed as event args), collating the selected customer's orders in a 'model' object and once obtained, the model can then be 'posted' back to the view (form) by means of invoking a 'rightPanel_load' routine and passing that model.

The form/view should remain as lightweight and dumb as possible, leaving all business logic to be defined in the other now decoupled middleware layers and act purely on events.

On mobile at the minute so posting examples isn't easy but will update in due course.

Have a good read on MVC architecture and also on object oriented design principles (SOLID is a good starting point), this should get you in the right mindset for it and once you 'get it', you'll have that lightbulb moment, the fog clears and suddenly you'll be flying!

a) define an event - say selectionchange. If should be high level and expressed in terms of the model data

b) each view with a selection (your left pane for example) exposes this event

c) any view that wants to subscribe (your right pane for example) attaches itself to the event exposed by (b)

You should read up on defining and using events (most good c# books will have this)

Where it gets interesting is then having some form of brokerage system so that consumers can find event publishers, this removes the need for (c) to know the name of (b)

For your simple 2 pane system what I have described is maybe overkill, but it will be interesting to implement and adds more long term flexibility