Cloning a form on an extended desktop

Question

Here is my situation (sorry for being long-winded, but I'm finding it difficult to describe this concisely):

We have a C# application (that we develop) that runs on a system with two monitors. However, each monitor faces a different user. That is, user 1, who has control, only sees monitor A and user 2, who has a 'read-only' position only sees monitor B. Up until now, we have been using a cloned display, such that A and B display the same information. However, it is desirable to be able to display different things to users 1 and 2 at specific instances in the workflow.

This calls for a situation where the desktop is sometimes Cloned and other times is Extended. Unfortunately, this solution seems undesirable to me because of what happens visually when you switch between desktop modes (screen goes black, temporary repositioning of windows) - it's basically not a clean transition. This is why I'm exploring alternatives.

Obviously, a Cloned-only solution won't work, so that leaves Extended mode.

Extended mode easily allows me to display two different forms on Monitors A and B, but what can I do for the times I want both monitors showing the same thing? Is there a way for me to show a "copy" or "clone" of a C# System.Windows.Forms.Form while the original is open, that reflects the same information?

Is there another solution to this problem that I'm overlooking? Or is the "switch between display modes using DisplaySwitch.exe" approach as good as it gets?

(assume we have complete control over the platform - hardware and software)

Answer 1

Consider using a remote access program like TightVNC. It can operate in loopback mode, displaying the main monitor image in the client program. Which you then have to move to the second monitor to get the clone. Together with the custom form that you minimize and restore.

Answer 2

To elaborate on my comment now that I have more time.

Rather than trying to clone Form A into Form B, set up some kind of communication layer between the two, such that Form A doesn't care what it's communicating with or whether the data displayed is the same or completely different.

The easiest way to do this is to hook a mediator into events on Form A and, when those events are triggered, send the necessary data to Form B to render it.

In the case where the data is the same, this could be as simple as taking a snapshot every time Form A updates and rendering it on Form B (much like harvardflu's answer, but putting that logic in a mediator), or you could take it as far as running the application process in another thread and updating Form A and Form B simultaneously through different mediators (though, as you suggest, this will probably be a major reengineering).

It is likely that the optimal solution is somewhere in between.