In the DiagramView, when scrolling a TreeViewNode by clicking and dragging the scrollbar , the contents of the node do not change until I have stopped for a moment.

BUT, the contents in the Overview window do change in real time as the scrolling occurs.

This is happening on a Windows 7 Ultimate x64 workstation.

It works as expected exporting the diagram and loading into identical app on a Windows 2003 x86 server instance.

Nothing in the TreeViewNode (including the scrollbar) repaints until either I have stopped for anything longer than a fraction of a second or change scroll direction.

But you can see the scrolling in the Overview window as expected.

It's a quad core i7 920 CPU (one of the gruntiest cpus around), nothing else happening on the system. 

It doesn't seem to happen on the addition of the first node, but will start after the second or third.

Will keep on playing and get back to you.

Narrowed it down to only happening when I have an Overview window visible.

Extended the simple app to have an Overview control side by side with the DiagramView, and added a button to toggle the Visible of the Overview.

If Overview is not visible, scrolling works as expected.

I have emailed the VS2008 project and a sample XML file.

Unfortunately the proper app already does have the Overview in a floating panel/window by default using a VS2008 style docking framework from DevExpress.


Can you please send me an updated sample project with your recommended implementation.

We've found that when the Overview and DiagramView are in the same window, as in your sample, you can call diagramView.BringToFront() to make the view repaint immediately while scrolling tree nodes. The Overview still lags behind for a part of a second, but that's the normal behavior you get under XP anyway.

If you want the overview to repaint immediately too, you might do that by deriving from Overview, handling the diagram.Repaint event, and calling the base.OnPaint from the handler. Otherwise the default Repaint handler simply invalidates the overview and it is refreshed later when the system sends WM_PAINT and calls OnPaint.

I hope that helps,
Stoyan

I didn't meant these options, but the case when both DiagramView and Overview are in the same form. We've only added BringToFront to the form constructor, without changing anything else:

public Form1()
{
	InitializeComponent();
	Diagram.RegisterItemClass(typeof(TableNode), "custom:TableNode", 1);
	diagramView1.BringToFront();
}
 

The result is that the DiagramView is repainted immediately, and the Overview lags, as in your point 2. This is the behavior by design we've had for years. We don't plan changing that to make the overview repaint immediately - it would just slow down all user interaction without adding anything beneficial.

Regarding repainting the DiagramView - we'll fix that for the next release. The active view is usually repainted immediately during item modification, but we've overlooked the case when scrolling treeviews - the control just calls Invalidate in this case and repaints after the system decides to call OnPaint. Apparently it takes hundreds of items, an Overview and Windows 7 to notice this problem.

Stoyan