Null Reference Exception and Invalid Operation Exceptions

Question

I'm getting some strange exceptions while creating and then later updating a dynamically generated graph.
I can catch and ignore them, but after a second or two I see the graph flicker and sometimes disappear when I do so.

Looking for any help with these, thanks!

The first seems similary to the other post about Null Reference exception

   at Microsoft.Msagl.GeometryGraph.PumpTheBoxToTheGraph(Rectangle& b) in C:\dev\MSAGL_RTMJune2008\LayoutEngine\GraphLayoutApi\GeometryGraph.cs:line 600
   at Microsoft.Msagl.GeometryGraph.PumpTheBoxToTheGraphWithMargins() in C:\dev\MSAGL_RTMJune2008\LayoutEngine\GraphLayoutApi\GeometryGraph.cs:line 585
   at Microsoft.Msagl.Engine.RunPostLayering() in C:\dev\MSAGL_RTMJune2008\LayoutEngine\Engine\Engine.cs:line 241
   at Microsoft.Msagl.Engine.Run() in C:\dev\MSAGL_RTMJune2008\LayoutEngine\Engine\Engine.cs:line 226
   at Microsoft.Msagl.SugiyamaLayoutSettings.CalculateLayout(GeometryGraph msaglGraph) in C:\dev\MSAGL_RTMJune2008\LayoutEngine\GraphLayoutApi\SugiyamaLayoutSettings.cs:line 187
   at Microsoft.Msagl.GeometryGraph.CalculateLayout() in C:\dev\MSAGL_RTMJune2008\LayoutEngine\GraphLayoutApi\GeometryGraph.cs:line 416
   at Microsoft.Msagl.GraphViewerGdi.GViewer.LayoutAndCreateDGraph() in C:\dev\MSAGL_RTMJune2008\GraphViewerGDI\GViewer.cs:line 962
   at Microsoft.Msagl.GraphViewerGdi.GViewer.CalculateLayout(Graph graph) in C:\dev\MSAGL_RTMJune2008\GraphViewerGDI\GViewer.cs:line 1498
   at Microsoft.Msagl.GraphViewerGdi.GraphRenderer.CalculateLayout() in C:\dev\MSAGL_RTMJune2008\GraphViewerGDI\GraphRenderer.cs:line 28
   at Microsoft.Msagl.GraphViewerGdi.GraphRenderer.Render(Graphics graphics, Rectangle rect) in C:\dev\MSAGL_RTMJune2008\GraphViewerGDI\GraphRenderer.cs:line 59
   at BroadbandConfig.Controls.WirelessGraphControl.paintGraph(Graph g, Rectangle gClip, Graphics graphics) in C:\Documents and Settings\Trevor Ackerman\My Documents\Visual Studio 2005\Projects\BroadbandConfig-msagl-trial\BroadbandConfig.Controls\WirelessGraphControl.cs:line 720
   at BroadbandConfig.Controls.WirelessGraphControl.OnPaint(PaintEventArgs e) in C:\Documents and Settings\Trevor Ackerman\My Documents\Visual Studio 2005\Projects\BroadbandConfig-msagl-trial\BroadbandConfig.Controls\WirelessGraphControl.cs:line 732
   at System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer, Boolean disposeEventArgs)
   at System.Windows.Forms.Control.WmPaint(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
   at System.Windows.Forms.ContainerControl.WndProc(Message& m)
   at System.Windows.Forms.UserControl.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
   at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.Run(Form mainForm)
   at BroadbandConfig.Program.Main() in C:\Documents and Settings\Trevor Ackerman\My Documents\Visual Studio 2005\Projects\BroadbandConfig-msagl-trial\BroadbandConfig\Program.cs:line 17
   at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
   at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
   at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
   at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()

And the other is InvalidOperationException

"a node with id 63:F8:E7 does note the boundary curve set"

   at Microsoft.Msagl.SugiyamaLayoutSettings.CalculateLayout(GeometryGraph msaglGraph) in C:\dev\MSAGL_RTMJune2008\LayoutEngine\GraphLayoutApi\SugiyamaLayoutSettings.cs:line 157
   at Microsoft.Msagl.GeometryGraph.CalculateLayout() in C:\dev\MSAGL_RTMJune2008\LayoutEngine\GraphLayoutApi\GeometryGraph.cs:line 416
   at BroadbandConfig.Controls.WirelessGraphControl.periodicWorker_DoWork(Object sender, DoWorkEventArgs e) in C:\Documents and Settings\Trevor Ackerman\My Documents\Visual Studio 2005\Projects\BroadbandConfig-msagl-trial\BroadbandConfig.Controls\WirelessGraphControl.cs:line 332
   at System.ComponentModel.BackgroundWorker.OnDoWork(DoWorkEventArgs e)
   at System.ComponentModel.BackgroundWorker.WorkerThreadStart(Object argument)

Answer 1

it looks like you are changing the graph while the layout is being calculated on this graph.
Thanks,
Lev

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Lev Nachmanson

Answer 2

I'm getting some strange exceptions while creating and then later updating a dynamically generated graph.
I can catch and ignore them, but after a second or two I see the graph flicker and sometimes disappear when I do so.

I wonder if these exceptions from different threads? Can you provide more information?

Answer 3

Sorry for the huge delay. Yes, the layout is calculated in a separate thread.

Thanks,

Lev

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Lev Nachmanson