Object Ref errors

[James Foster]

With the latest release, we are seeing new random Object Ref errors coming out of the Syncfusion code. We have the control on a tab, and these errors occur when users are on another tab doing routine operations like clicking on dropdown lists, radio buttons, buttons, etc in non-Syncfusion code.

Looking at the stack trace, these errors come straight out of Syncfusion code. Any idea?

Here is the exception:

Message:
Object reference not set to an instance of an object.

Stack Trace:

at Syncfusion.Windows.Diagram.LineConnector.getNodeRect(Node n)
at Syncfusion.Windows.Diagram.LineConnector.UpdateConnectorPathGeometry()
at Syncfusion.Windows.Diagram.LineConnector.Line_PropertyChanged(Object sender, PropertyChangedEventArgs e)
at System.ComponentModel.PropertyChangedEventHandler.Invoke(Object sender, PropertyChangedEventArgs e)
at Syncfusion.Windows.Diagram.Node.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
at System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)
at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType)
at System.Windows.DependencyObject.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType, Boolean isInternal)
at System.Windows.DependencyObject.SetValue(DependencyProperty dp, Object value)
at Syncfusion.Windows.Diagram.Node.set_Position(Point value)
at Syncfusion.Windows.Diagram.Node.set_PxPosition(Point value)
at Syncfusion.Windows.Diagram.Node.Node_LayoutUpdated(Object sender, EventArgs e)
at System.Windows.ContextLayoutManager.fireLayoutUpdateEvent()
at System.Windows.ContextLayoutManager.UpdateLayout()
at System.Windows.ContextLayoutManager.UpdateLayoutCallback(Object arg)
at System.Windows.Media.MediaContext.InvokeOnRenderCallback.DoWork()
at System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks()
at System.Windows.Media.MediaContext.RenderMessageHandlerCore(Object resizedCompositionTarget)
at System.Windows.Media.MediaContext.RenderMessageHandler(Object resizedCompositionTarget)
at System.Windows.Media.MediaContext.Resize(ICompositionTarget resizedCompositionTarget)
at System.Windows.Interop.HwndTarget.OnResize()
at System.Windows.Interop.HwndTarget.HandleMessage(WindowMessage msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Interop.HwndSource.HwndTargetFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)

Target Site:

Syncfusion.Diagram.Wpf

Data:

System.Windows.Rect getNodeRect(Syncfusion.Windows.Diagram.Node)

Source:

System.Collections.ListDictionaryInternal

[Ramya Thirugnanam]

Hi James,

We are unable to reproduce the reported issue ”Object reference not set to an instance of an object” in 9.4.0.62v. But with the help of the given stack trace we are able to see there are some possibilities to causes this exceptions. We will provide a patch for this fix on December 12th 2011.

Possibilities:
In getNodeRect function, There is no such a possibility that the Node(argument ) to be ‘null’, but there are chances that internal variable dc (DiagramControl) to be null.
We tried to reproduce this issue in many scenario by hosting diagram in tabcontrol, but still we are not able to reproduce this issue. We can fix this issue by null value check, but the root cause of the issue is still unknown. It would be the great help for us, if you provide a more details about the scenario to reproduce this issue.

Please let us know if you have any concerns.
Regards,
Ramya