[Solved] NullReferenceException in scrolling

[Piotr]

For RadJumpList of many elements(>300) with grouping  where ItemTemplate  is big, when you try to scroll fastquickly
sometimes can get this exception:

Przechwycony wyjątek:

NullReferenceException

"NullReferenceException"

 

Więcej informacji:

 

System.NullReferenceException: NullReferenceException

   at Telerik.Windows.Controls.RadVirtualizingDataControl.OnContainerStateChanged(RadVirtualizingDataControlItem container, IDataSourceItem item, ItemState state)

   at Telerik.Windows.Controls.VirtualizationStrategy.GetContainerForItem(IDataSourceItem item, Int32 insertAt)

   at Telerik.Windows.Controls.StackVirtualizationStrategy.GetContainerForItem(IDataSourceItem item, Int32 insertAt)

   at Telerik.Windows.Controls.VirtualizationStrategy.GetContainerForItem(IDataSourceItem item, Boolean insertLast)

   at Telerik.Windows.Controls.VirtualizationStrategy.ManageLowerViewport(Boolean recycle)

   at Telerik.Windows.Controls.RadVirtualizingDataControl.ManageViewport()

   at Telerik.Windows.Controls.RadVirtualizingDataControl.BalanceVisualSpace()

   at Telerik.Windows.Controls.RadVirtualizingDataControl.OnVerticalScrollOffsetChanged(Boolean balanceImmediately)

   at Telerik.Windows.Controls.RadDataBoundListBox.OnVerticalScrollOffsetChanged(Boolean balanceImmediately)

   at Telerik.Windows.Controls.RadJumpList.OnVerticalScrollOffsetChanged(Boolean balanceImmediately)

   at Telerik.Windows.Controls.RadVirtualizingDataControl.h()

   at System.Reflection.RuntimeMethodInfo.InternalInvoke(RuntimeMethodInfo rtmi, Object obj, BindingFlags invokeAttr, Binder binder, Object parameters, CultureInfo culture, Boolean isBinderDefault, Assembly caller, Boolean verifyAccess, StackCrawlMark& stackMark)

   at System.Reflection.RuntimeMethodInfo.InternalInvoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, StackCrawlMark& stackMark)

   at System.Reflection.MethodBase.Invoke(Object obj, Object[] parameters)

   at System.Delegate.DynamicInvokeOne(Object[] args)

   at System.MulticastDelegate.DynamicInvokeImpl(Object[] args)

   at System.Windows.Threading.DispatcherOperation.Invoke()

   at System.Windows.Threading.Dispatcher.Dispatch(DispatcherPriority priority)

   at System.Windows.Threading.Dispatcher.OnInvoke(Object context)

   at System.Windows.Hosting.CallbackCookie.Invoke(Object[] args)

   at System.Windows.RuntimeHost.ManagedHost.InvokeDelegate(IntPtr pHandle, Int32 nParamCount, ScriptParam[] pParams, ScriptParam& pResult)


The problem is easier to call on slow phones.

[Deyan]

Hi Piotr,

Thanks for writing and for reporting this issue.

Could you please provide us with sample project that we can use to reproduce the scenario on our side and be able to debug it. We are currently not aware of similar issues and therefore a demo project would be really helpful for us to investigate.

Please note that you will have to open a new support ticket in order to be able to upload the project.

Kind regards,
Deyan
the Telerik team