There isn't any built-in thread synchronization. However you could remove the Diagram from the DiagramView to make it safe to access from another thread:

private Diagram d;
private void miViewThreadTest_Click(object sender, EventArgs e)
{
	d = diagramView.Diagram;
	diagramView.Diagram = new Diagram();
	diagramView.Diagram.BackgroundImage = d.CreateImage();
	BackgroundWorker w = new BackgroundWorker();
	w.DoWork += w_DoWork;
	w.RunWorkerAsync();
}

void w_DoWork(object sender, DoWorkEventArgs e)
{
	Random r = new Random();
	for (int i = 0; i < 100; i++)
	{
		d.Factory.CreateShapeNode(r.Next(200), r.Next(200), 10, 10);
		Thread.Sleep(10);
	}
	diagramView.Diagram = d;
} 

I hope that helps,
Stoyan

I have such scenario:

//-----------------------------------------------------------
public delegate void TRefreshDelegate();
private TRefreshDelegate RefreshDelegate = new TRefreshDelegate(RefreshCore);
//-----------------------------------------------------------
public void Refresh()
{
if (this.InvokeRequired)
this.Invoke(RefreshDelegate, null);
else
RefreshCore();
}
//-----------------------------------------------------------
public void RefreshCore()
{
view.Refresh();
}

In a Dedicated thread ---
private static void ProberOp(Object state)
{
while (true)
{
.....
diagram.Nodes.Remove(node1); // ** Error point
diagram.Nodes.Add(node2);
Refresh();
Thread.Sleep(1000);
}
}

In my first predicate that the diagram is not control-ui -sensitive(just doc feature), so can ui-threading-free. and can safely run the 'diagram.Nodes.Remove()'.
and let Refresh() to Control.Invoke() the view.Refresh().
but the result is:
error message:"Cross-thread operation not valid: Control '' accessed from a thread other than the thread it was created on"

and error called stack show:
Source=System.Windows.Forms
StackTrace:
at System.Windows.Forms.Control.get_Handle()
at System.Windows.Forms.Control.SetVisibleCore(Boolean value)
at System.Windows.Forms.Control.set_Visible(Boolean value)
at MindFusion.Diagramming.WinForms.DiagramView.ResetScrollbars()
at MindFusion.Diagramming.WinForms.DiagramView.x115588a415d2dbd9(Object xe0292b9ed559da7d, EventArgs xfbf34718e704c6bc)
at MindFusion.Diagramming.Diagram.ResetDocSize()
at MindFusion.Diagramming.Diagram.xaf4db0d26185109c()
at MindFusion.Diagramming.Diagram.RemoveItem(DiagramItem item)
at MindFusion.Diagramming.Commands.RemoveItemCmd.Execute(Boolean undoEnabled)
at MindFusion.Diagramming.UndoManager.xdf8cd2685f83d9b7(Command x61b060a94340c4fc)
at MindFusion.Diagramming.Diagram.x7d877b7264517b49(DiagramItem xccb63ca5f63dc470)
at MindFusion.Diagramming.Diagram.xba535330911dfd91(Object xe0292b9ed559da7d, ItemEventArgs xfbf34718e704c6bc)
at MindFusion.Diagramming.ItemCollectionBase.RaiseRemoving(DiagramItem item)
at MindFusion.Diagramming.DiagramNodeCollection.x52b190e626f65140(DiagramNode xda5bf54deb817e37, Boolean x808547253555a9ba)
at MindFusion.Diagramming.DiagramNodeCollection.Remove(DiagramNode node)
at Pn.Doc.TPlace.RemoveToken(Int32 cnt) in E:\myProjects\0801_Cy\03_Code\Cy2011\Pn\Pn\Place.cs:line 72
at Pn.Doc.TTransition.ProberOp(Object state) in E:\myProjects\0801_Cy\03_Code\Cy2011\Pn\Pn\Transition.cs:line 85
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart(Object obj)

this mean the diagram access the view when diagram.Nodes.Add(node).

so my question is: is there any switch function, when I do not want the view be update in some case? (switch off the refreshing the view)

so, the code logic will seems confusion when multi-threading.
how about WPF version of Diagramming?

will the next version deal with it?

The WPF version isn't thread-safe either. I'm afraid we don't have plans to add thread-safety at this time.