Problems while changing the data of itemSource of ScheduleView in another thread.

[Qizhang]

I got this error while updating the data of schedule view in another thread , not in dispatching thread. Per the exception message, the collection was changed already while it was being enumerated, in line 4625 in ScheduleViewBase.cs, which was triggered in the method OnQueryGoToNextAppointmentCanExecuted in ScheduleViewBase.

The situation is that I have to update the data in a timer , which will execute update in another thread. Could you please give some suggestion about how to fix it, or some work around? I was trapped for almost a week.

The message of the exception is attached.
Thanks a lot.

[Qizhang]

Sorry the attachment was uploaded successfully. I pasted it here as following:

A first chance exception of type 'System.InvalidOperationException' occurred in mscorlib.dll
'ATOMS.CrewManagerApp.exe' (Managed (v4.0.30319)): Loaded 'C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Transactions.resources\v4.0_4.0.0.0_zh-Hans_b77a5c561934e089\System.Transactions.resources.dll'
System.Transactions Critical: 0 : <TraceRecord xmlns="http://schemas.microsoft.com/2004/10/E2ETraceEvent/TraceRecord" Severity="Critical"><TraceIdentifier>http://msdn.microsoft.com/TraceCodes/System/ActivityTracing/2004/07/Reliability/Exception/Unhandled</TraceIdentifier><Description>未处理的异常</Description><AppDomain>ATOMS.CrewManagerApp.exe</AppDomain><Exception><ExceptionType>System.InvalidOperationException, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</ExceptionType><Message>集合已修改；可能无法执行枚举操作。</Message><StackTrace>   在 System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource)
   在 System.Collections.Generic.List`1.Enumerator.MoveNextRare()
   在 System.Collections.Generic.List`1.Enumerator.MoveNext()
   在 System.Linq.Enumerable.&amp;lt;OfTypeIterator&amp;gt;d__aa`1.MoveNext()
   在 System.Linq.Enumerable.WhereEnumerableIterator`1.MoveNext()
   在 System.Linq.Enumerable.&amp;lt;SelectManyIterator&amp;gt;d__14`2.MoveNext()
   在 System.Linq.Enumerable.WhereEnumerableIterator`1.MoveNext()
   在 System.Linq.Enumerable.Any[TSource](IEnumerable`1 source)
   在 Telerik.Windows.Controls.ScheduleViewBase.HasAppointmentsInRange(IDateSpan range, Boolean skipIntersectedWithTheRangeAppointments, Boolean moveForward, DateTimeInterval interval)
   在 Telerik.Windows.Controls.ScheduleViewBase.OnQueryGoToPreviousAppointmentCanExecuted(Object sender, CanExecuteRoutedEventArgs e)
   在 System.Windows.Input.CommandBinding.OnCanExecute(Object sender, CanExecuteRoutedEventArgs e)
   在 System.Windows.Input.CommandManager.FindCommandBinding(Object sender, RoutedEventArgs e, ICommand command, Boolean execute)
   在 System.Windows.Input.CommandManager.OnCanExecute(Object sender, CanExecuteRoutedEventArgs e)
   在 System.Windows.UIElement.OnCanExecuteThunk(Object sender, CanExecuteRoutedEventArgs e)
   在 System.Windows.Input.CanExecuteRoutedEventArgs.InvokeEventHandler(Delegate genericHandler, Object target)
   在 System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
   在 System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
   在 System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   在 System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   在 System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)
   在 System.Windows.Input.RoutedCommand.CriticalCanExecuteWrapper(Object parameter, IInputElement target, Boolean trusted, CanExecuteRoutedEventArgs args)
   在 System.Windows.Input.RoutedCommand.CanExecuteImpl(Object parameter, IInputElement target, Boolean trusted, Boolean&amp;amp; continueRouting)
   在 System.Windows.Input.RoutedCommand.CriticalCanExecute(Object parameter, IInputElement target, Boolean trusted, Boolean&amp;amp; continueRouting)
   在 System.Windows.Input.RoutedCommand.CanExecute(Object parameter, IInputElement target)
   在 MS.Internal.Commands.CommandHelpers.CanExecuteCommandSource(ICommandSource commandSource)
   在 System.Windows.Controls.Primitives.ButtonBase.UpdateCanExecute()
   在 System.Windows.Controls.Primitives.ButtonBase.OnCanExecuteChanged(Object sender, EventArgs e)
   在 System.Windows.Input.CanExecuteChangedEventManager.HandlerSink.OnCanExecuteChanged(Object sender, EventArgs e)
   在 System.Windows.WeakEventManager.ListenerList.DeliverEvent(Listener&amp;amp; listener, Object sender, EventArgs args, Type managerType)
   在 System.Windows.WeakEventManager.ListenerList.DeliverEvent(Object sender, EventArgs args, Type managerType)
   在 System.Windows.WeakEventManager.DeliverEvent(Object sender, EventArgs args)
   在 System.Windows.Input.CommandManager.RequerySuggestedEventManager.OnRequerySuggested(Object sender, EventArgs args)
   在 System.Windows.Input.CommandManager.RaiseRequerySuggested(Object obj)
   在 System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   在 MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
   在 System.Windows.Threading.DispatcherOperation.InvokeImpl()
   在 System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
   在 System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   在 System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   在 System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   在 System.Windows.Threading.DispatcherOperation.Invoke()
   在 System.Windows.Threading.Dispatcher.ProcessQueue()
   在 System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean&amp;amp; handled)
   在 MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean&amp;amp; handled)
   在 MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
   在 System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   在 MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
   在 System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
   在 MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   在 MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG&amp;amp; msg)
   在 System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
   在 System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
   在 System.Windows.Threading.Dispatcher.Run()
   在 System.Windows.Application.RunDispatcher(Object ignore)
   在 System.Windows.Application.RunInternal(Window window)
   在 System.Windows.Application.Run(Window window)
   在 System.Windows.Application.Run()
   在 ATOMS.CrewManagerApp.App.Main() 位置 D:\working\SMRT\ATMOS\SRC\ATOMS.CrewManagerApp\obj\x86\Debug\App.g.cs:行号 0</StackTrace><ExceptionString>System.InvalidOperationException: 集合已修改；可能无法执行枚举操作。
   在 System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource)
   在 System.Collections.Generic.List`1.Enumerator.MoveNextRare()
   在 System.Collections.Generic.List`1.Enumerator.MoveNext()
   在 System.Linq.Enumerable.&amp;lt;OfTypeIterator&amp;gt;d__aa`1.MoveNext()
   在 System.Linq.Enumerable.WhereEnumerableIterator`1.MoveNext()
   在 System.Linq.Enumerable.&amp;lt;SelectManyIterator&amp;gt;d__14`2.MoveNext()
   在 System.Linq.Enumerable.WhereEnumerableIterator`1.MoveNext()
   在 System.Linq.Enumerable.Any[TSource](IEnumerable`1 source)
   在 Telerik.Windows.Controls.ScheduleViewBase.HasAppointmentsInRange(IDateSpan range, Boolean skipIntersectedWithTheRangeAppointments, Boolean moveForward, DateTimeInterval interval)
   在 Telerik.Windows.Controls.ScheduleViewBase.OnQueryGoToPreviousAppointmentCanExecuted(Object sender, CanExecuteRoutedEventArgs e)
   在 System.Windows.Input.CommandBinding.OnCanExecute(Object sender, CanExecuteRoutedEventArgs e)
   在 System.Windows.Input.CommandManager.FindCommandBinding(Object sender, RoutedEventArgs e, ICommand command, Boolean execute)
   在 System.Windows.Input.CommandManager.OnCanExecute(Object sender, CanExecuteRoutedEventArgs e)
   在 System.Windows.UIElement.OnCanExecuteThunk(Object sender, CanExecuteRoutedEventArgs e)
   在 System.Windows.Input.CanExecuteRoutedEventArgs.InvokeEventHandler(Delegate genericHandler, Object target)
   在 System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
   在 System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
   在 System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   在 System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   在 System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)
   在 System.Windows.Input.RoutedCommand.CriticalCanExecuteWrapper(Object parameter, IInputElement target, Boolean trusted, CanExecuteRoutedEventArgs args)
   在 System.Windows.Input.RoutedCommand.CanExecuteImpl(Object parameter, IInputElement target, Boolean trusted, Boolean&amp;amp; continueRouting)
   在 System.Windows.Input.RoutedCommand.CriticalCanExecute(Object parameter, IInputElement target, Boolean trusted, Boolean&amp;amp; continueRouting)
   在 System.Windows.Input.RoutedCommand.CanExecute(Object parameter, IInputElement target)
   在 MS.Internal.Commands.CommandHelpers.CanExecuteCommandSource(ICommandSource commandSource)
   在 System.Windows.Controls.Primitives.ButtonBase.UpdateCanExecute()
   在 System.Windows.Controls.Primitives.ButtonBase.OnCanExecuteChanged(Object sender, EventArgs e)
   在 System.Windows.Input.CanExecuteChangedEventManager.HandlerSink.OnCanExecuteChanged(Object sender, EventArgs e)
   在 System.Windows.WeakEventManager.ListenerList.DeliverEvent(Listener&amp;amp; listener, Object sender, EventArgs args, Type managerType)
   在 System.Windows.WeakEventManager.ListenerList.DeliverEvent(Object sender, EventArgs args, Type managerType)
   在 System.Windows.WeakEventManager.DeliverEvent(Object sender, EventArgs args)
   在 System.Windows.Input.CommandManager.RequerySuggestedEventManager.OnRequerySuggested(Object sender, EventArgs args)
   在 System.Windows.Input.CommandManager.RaiseRequerySuggested(Object obj)
   在 System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   在 MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
   在 System.Windows.Threading.DispatcherOperation.InvokeImpl()
   在 System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
   在 System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   在 System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   在 System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   在 System.Windows.Threading.DispatcherOperation.Invoke()
   在 System.Windows.Threading.Dispatcher.ProcessQueue()
   在 System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean&amp;amp; handled)
   在 MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean&amp;amp; handled)
   在 MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
   在 System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   在 MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
   在 System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
   在 MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   在 MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG&amp;amp; msg)
   在 System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
   在 System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
   在 System.Windows.Threading.Dispatcher.Run()
   在 System.Windows.Application.RunDispatcher(Object ignore)
   在 System.Windows.Application.RunInternal(Window window)
   在 System.Windows.Application.Run(Window window)
   在 System.Windows.Application.Run()
   在 ATOMS.CrewManagerApp.App.Main() 

[Konstantina]

Hi,

Could you please give us some more detail about your application - are you using PRISM, or any other information you find essential. Also, if you provide us with very basic and simple application which simulates your scenario and approach, it will be much easier for us to track down the source of the problem.

Looking forward to your reply.

Regards,
Konstantina
Telerik