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exception when dragging a DockingManager panel

Thread ID:





56648 Feb 18,2007 08:15 AM UTC Apr 20,2007 07:58 AM UTC WinForms 3
Tags: Tools
Ryan Hardoon
Asked On February 18, 2007 08:15 AM UTC

I get a reoccuring exception whenever I start dragging any of the docking panels.

Here are the details, hoping someone here has confronted the problem successfully.

thanks in advance.


System.NullReferenceException was unhandled
Message="Object reference not set to an instance of an object."
at Syncfusion.Windows.Forms.Tools.Renderers.DockingManagerRenderer.PaintDockedControl(Graphics g, Rectangle rectangle, PaintDockControlArgs args)
at Syncfusion.Windows.Forms.Tools.FloatingForm.PaintNCArea()
at Syncfusion.Windows.Forms.Tools.FloatingForm..ctor(DockingManager dmgr)
at Syncfusion.Windows.Forms.Tools.DockingManager.CreateFloatingForm()
at Syncfusion.Windows.Forms.Tools.DockHostController.SelectActivationForm(Boolean& restored)
at Syncfusion.Windows.Forms.Tools.DockHostController.CreateFloatingFrame(Point ptlocation, Boolean show)
at Syncfusion.Windows.Forms.Tools.DockHostController.TransitDockToFloat()
at Syncfusion.Windows.Forms.Tools.DockHostController.ApplyDockInfo()
at Syncfusion.Windows.Forms.Tools.WhidbeyDragProvider.ProcessMouseMove(DockControllerBase controller, IDraggable ctrl, Point ptscreen)
at Syncfusion.Windows.Forms.Tools.DockHostController.HandleMouseMoveImp(MouseButtons button, Point pt)
at Syncfusion.Windows.Forms.Tools.DockHost.OnMouseMove(MouseEventArgs e)
at System.Windows.Forms.Control.WmMouseMove(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 Syncfusion.Windows.Forms.Tools.DockHost.WndProc(Message& msg)
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 DockingTest.Program.Main() in C:\Documents and Settings\Administrator\Desktop\DockingTest\DockingTest\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()

Golda Rebecal [Syncfusion]
Replied On February 19, 2007 02:36 PM UTC

Hi Ryan,

I am afraid that I am not able to reproduce the issue you have mentioned. I created a sample to reproduce the issue and I found it working fine. Herewith I have attached the sample.


Please try running the above sample. If still the issue exists, kindly try reproducing it with this sample and send it back to me so that it would help me to find out the cause of the issue.

Thanks for your interest in Syncfusion products

Best Regards,

Vikram Bhavsar
Replied On April 19, 2007 02:35 PM UTC

I am seeing this exception as well. I have found another post with a user seeing the same problem (with an example of how to reproduce it):


Once of the messages of te exception is:
Syncfusion.Windows.Forms.Tools.WhidbeyDragProvider.GetMainFormController(Point ptscreen)

Has anyone else seen this, or found a fix/workaround for it?


Poly J [Syncfusion]
Replied On April 20, 2007 07:58 AM UTC

Hi Vik,

Thanks for your interest in Syncfusion Products.

Could you please let me know the Essential Studio Version you are using. Exception when dragging Docking window is reported in Version and this issue is fixed in the next version.

Best Regards,


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