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WhidbeyDragProvider.UpdateDragControlPosition causes NullReferenceException

Thread ID:





47192 Jul 31,2006 12:00 AM UTC Aug 1,2006 08:03 PM UTC WinForms 3
Tags: Tools
Dmitry Bakuntsev
Asked On July 31, 2006 12:00 AM UTC


the attached sample demonstrates error conditions that occur when two independent (and not linked to each other) docking managers are used in an application. One docking manager handles dockable views in the main window. Yet another docking manager handles exactly two sub-views (view #2 and view #3) in a view docked in the main window (view #1). It is worth of mentioning that either view #2 or view #3 is auto-hidden on load (for the sake of argument, let''s say it is view #2), and the docking manager that works within view #1 confines has "Dock with Fill Style" property enabled.

Now, everything works fine (e.g. view #1 can be undocked from its default location, and re-docked somewhere else) until the size of view #2 (the one that is auto-hidden on load) changes. While the application appears to be performing normally, it is no longer the case. View #1 can no longer be re-docked within its docking manager constraints without causing a NullReferenceException, like the one below:

System.NullReferenceException: Object reference not set to an instance of an object.
at Syncfusion.Windows.Forms.Tools.WhidbeyDragProvider.UpdateDragControlPosition(Point ptscreen)
at Syncfusion.Windows.Forms.Tools.WhidbeyDragProvider.HostControl_Move(Object sender, EventArgs e)
at System.Windows.Forms.Control.OnMove(EventArgs e)
at System.Windows.Forms.Control.OnLocationChanged(EventArgs e)
at System.Windows.Forms.Control.UpdateBounds(Int32 x, Int32 y, Int32 width, Int32 height, Int32 clientWidth, Int32 clientHeight)
at System.Windows.Forms.Control.UpdateBounds()
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.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

************** Loaded Assemblies **************
Assembly Version:
Win32 Version:
CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/Syncfusion.Tools.Windows/
Assembly Version:
Win32 Version:
CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/Syncfusion.Shared.Base/
Assembly Version:
Win32 Version:
CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/Syncfusion.Core/



Joy K George [Syncfusion]
Replied On July 31, 2006 09:30 PM UTC

Hi Dmitry,

We regret for the inconvenience caused.

I was able to reproduce the issue here with our latest source is free from this issue.Here is the steps which I used for testing.

1.Started the application.
2.Resized usercontrol2 in the Autohidden mode itself.
3.Redocked usercontrol1 to right.

This produced an exception with same stack trace which you have sent.But this worked fine with our latest source.

So could you please create a DirectTrac incident to obtain the new dll?

Thanks for choosing Syncfusion.

Dmitry Bakuntsev
Replied On August 1, 2006 01:53 AM UTC

Thank you for looking into this. Incident ID is #27310.


Joy K George [Syncfusion]
Replied On August 1, 2006 08:03 PM UTC

Hi Dmitry,

We have updated incident #27310.Please follow that.We will release a patch by thursday which contains this fix.



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