I have a .NET 4.0 WinForms application. A Form of the application contains a Grid – an System.Windows.Forms.DataGridView object
Suddenly I have got a (non-reproducible!) NullReferenceException in it. The call stack was the following:
System.NullReferenceException: Object reference not set to an instance of an object.
at System.Windows.Forms.DataGridView.UnwireEditingControlEvents()
at System.Windows.Forms.DataGridView.EndEdit(DataGridViewDataErrorContexts context, DataGridViewValidateCellInternal validateCell, Boolean fireCellLeave, Boolean fireCellEnter, Boolean fireRowLeave, Boolean fireRowEnter, Boolean fireLeave, Boolean keepFocus, Boolean resetCurrentCell, Boolean resetAnchorCell)
at System.Windows.Forms.DataGridView.SetCurrentCellAddressCore(Int32 columnIndex, Int32 rowIndex, Boolean setAnchorCellAddress, Boolean validateCurrentCell, Boolean throughMouseClick)
at System.Windows.Forms.DataGridView.set_CurrentCell(DataGridViewCell value)
at System.Windows.Forms.DataGridView.OnClearingRows()
at System.Windows.Forms.DataGridViewRowCollection.ClearInternal(Boolean recreateNewRow)
at System.Windows.Forms.DataGridView.RefreshRows(Boolean scrollIntoView)
at System.Windows.Forms.DataGridView.DataGridViewDataConnection.ProcessListChanged(ListChangedEventArgs e)
at System.Windows.Forms.DataGridView.DataGridViewDataConnection.currencyManager_ListChanged(Object sender, ListChangedEventArgs e)
at System.Windows.Forms.CurrencyManager.OnListChanged(ListChangedEventArgs e)
at System.Windows.Forms.CurrencyManager.List_ListChanged(Object sender, ListChangedEventArgs e)
at System.Windows.Forms.BindingSource.OnListChanged(ListChangedEventArgs e)
at System.Windows.Forms.BindingSource.InnerList_ListChanged(Object sender, ListChangedEventArgs e)
at System.ComponentModel.BindingList`1.OnListChanged(ListChangedEventArgs e)
at System.ComponentModel.BindingList`1.FireListChanged(ListChangedType type, Int32 index)
at System.ComponentModel.BindingList`1.ClearItems()
at System.Collections.ObjectModel.Collection`1.Clear()
at <My Code>;
The calls method Clear of a BindingList-derived list. The BindingList-derived list is, in turn, used in a BindingSource object. The BindingSource object is a datasource of the DataGridView.
I cannot understand – why this happens? And why it happens only sometimes? (to the moment I have seen the problem only once).
And how can this be avoided?
Ran into this myself just now. In my case, I noticed it only happens if the grid has more than about 10 rows or so and you immediately try to go to the last row. My workaround was, after setting the BindingSource, to manually set the current cell to a cell within the first row:
grdConditions.DataSource = myDataSource;
if (grdConditions.Rows.Count > 0)
grdConditions.CurrentCell = grdConditions[0, grdConditions.RowCount - 1];
Seemed to fix the issue for me.
I've inherited a fairly big project that needed upgrading from Silverlight 2 to Silverlight 4. I recently ran into an error trying to test the project.
Microsoft JScript runtime error: Unhandled Error in Silverlight Application Set property 'System.Windows.FrameworkElement.Style' threw an exception. [Line: 257 Position: 27] at System.Windows.Application.LoadComponent(Object component, Uri resourceLocator)
at ESM.Visualization.MainPage.InitializeComponent()
at ESM.Visualization.MainPage..ctor()
at ESM.Visualization.App.Application_Startup(Object sender, StartupEventArgs e)
at MS.Internal.CoreInvokeHandler.InvokeEventHandler(Int32 typeIndex, Delegate handlerDelegate, Object sender, Object args)
at MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, Int32 actualArgsTypeIndex, String eventName)
I think there might be some files that went missing between Silverlight 2 and 4, but I'm not sure where to start looking for changes to fix. Any help would be appreciated.
We have just recently deployed a Trusted, In-Browser, Silverlight 5 application to our Production webserver. We are getting fairly frequent ArgumentExceptions captured by the App.xaml.cs UnhandledException handler. So far we have been unable to determine the source of the exception.
We are not seeing the exception when running under the debugger (I have that explicitly enabled the exception for capture under Debug->Exceptions....). Some users see this error very frequently, while others never see the error. It doesn't seem to be a fatal error as the users can just click the OK button from the ErrorWindow that we display and everything functions normally.
To stop annoying the users, I have added a handler for ArgumentException types and just mark it as handled and continue on. However, I am still logging the errors and would really like to determine the actual source so that I can fix the problem. Just ignoring the exception doesn't seem like a long term solution.
The Stack trace is below and is the same for all ArgumentExceptions.
Any ideas on how I can troubleshoot better and determine the cause of this exception?
Thanks,
Tim
Unhandled Exception: [Arg_ArgumentException]
Arguments:
Debugging resource strings are unavailable. Often the key and arguments provide sufficient information to diagnose the problem. See http://go.microsoft.com/fwlink/?linkid=106663&Version=5.0.10411.00&File=mscorlib.dll&Key=Arg_ArgumentException :
at MS.Internal.XcpImports.CheckHResult(UInt32 hr)
at MS.Internal.XcpImports.SetValue(IManagedPeerBase obj, DependencyProperty property, Double d)
at MS.Internal.XcpImports.SetValue(IManagedPeerBase doh, DependencyProperty property, Object obj)
at System.Windows.DependencyObject.SetObjectValueToCore(DependencyProperty dp, Object value)
at System.Windows.DependencyObject.SetEffectiveValue(DependencyProperty property, EffectiveValueEntry& newEntry, Object newValue)
at System.Windows.DependencyObject.UpdateEffectiveValue(DependencyProperty property, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, ValueOperation operation)
at System.Windows.DependencyObject.RefreshExpression(DependencyProperty dp)
at System.Windows.Data.BindingExpression.SendDataToTarget()
at System.Windows.Data.BindingExpression.SourceAcquired()
at System.Windows.Data.BindingExpression.PerformTargetLoaded()
at System.Windows.Data.BindingExpression.TargetLoaded(Object o, RoutedEventArgs e)
at MS.Internal.CoreInvokeHandler.InvokeEventHandler(UInt32 typeIndex, Delegate handlerDelegate, Object sender, Object args)
at MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex
I am not new to WPF, but I can't figure out this problem:
I use an ObservableCollection<MyCustomType> that i bind to ComboBoxes, it's all working great as usual, but at some point i need to change the content of the collection (i retrieve a new set from the database, that may or may not contain part of the old one).
Now adding or removing elements is all done by WPF, but if you change the whole collection I found you had to raise PropertyChanged for the collection.
The problem is that sometimes it crashes giving me a not-so-friendly exception.
I'm unsure of what exactly triggers the crash, but if I don't touch the View and retrieve a new set from DB, it doesn't crash.
Here is some code:
public const string MyObsCollectionProperty = "MyObsCollection";
private ObservableCollection<MyCustomType> m_MyObsCollection;
public ObservableCollection<MyCustomType> MyObsCollection
{
get { return m_MyObsCollection; }
set
{
m_MyObsCollection = value;
RaisePropertyChanged(MyObsCollectionProperty); // <-- Crashes here
}
}
I get the exception: Unable to cast object of type 'MS.Internal.NamedObject' to type 'MyNameSpace.MyCustomType'
Please note that this exception comes from Prism, but it's probably just because i inherit from NotificationObject on my ViewModel.
I appreciate any help on this problem,
Regards,
LK.
EDIT: I think the problem comes from the ComboBox, and more specifically, from the way i set their properties.
I bind the ItemsSource property to an ObservableCollection, and to decide which element to select, I bind the SelectedValue to a field of an item of an ObservableCollection (the ComboBox is nested within a ListView).
I also set SelectedValuePath (you get the idea).
I guess when i change the first collection hell breaks lose on that setup. And it leaves it in peace when i don't touch the view because of virtualization (it is hidden at first).
ADDITION:
The InnerException is nulll.
Message: Unable to cast object of type 'MS.Internal.NamedObject' to type 'CocoonV4.DAL.WcfServiceCocoonV4.DekoTemplate'.
at Microsoft.Practices.Prism.Commands.DelegateCommand`1.<>c__DisplayClass6.<.ctor>b__3(Object o)
at Microsoft.Practices.Prism.Commands.DelegateCommandBase.CanExecute(Object parameter)
at Microsoft.Practices.Prism.Commands.DelegateCommandBase.System.Windows.Input.ICommand.CanExecute(Object parameter)
at System.Windows.Interactivity.InvokeCommandAction.Invoke(Object parameter)
at System.Windows.Interactivity.TriggerBase.InvokeActions(Object parameter)
at System.Windows.Interactivity.EventTriggerBase.OnEvent(EventArgs eventArgs)
at System.Windows.Interactivity.EventTriggerBase.OnEventImpl(Object sender, EventArgs eventArgs)
at System.Windows.Controls.SelectionChangedEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
at System.Windows.UIElement.RaiseEvent(RoutedEventArgs e)
at System.Windows.Controls.ComboBox.OnSelectionChanged(SelectionChangedEventArgs e)
at System.Windows.Controls.Primitives.Selector.InvokeSelectionChanged(List`1 unselectedItems, List`1 selectedItems)
at System.Windows.Controls.Primitives.Selector.SelectionChanger.End()
at System.Windows.Controls.Primitives.Selector.OnItemsChanged(NotifyCollectionChangedEventArgs e)
at System.Windows.Controls.ItemsControl.OnItemCollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)
at System.Collections.Specialized.NotifyCollectionChangedEventHandler.Invoke(Object sender, NotifyCollectionChangedEventArgs e)
at System.Windows.Data.CollectionView.OnCollectionChanged(NotifyCollectionChangedEventArgs args)
at System.Windows.Controls.ItemCollection.System.Windows.IWeakEventListener.ReceiveWeakEvent(Type managerType, Object sender, EventArgs e)
at System.Windows.WeakEventManager.DeliverEventToList(Object sender, EventArgs args, ListenerList list)
at System.Windows.WeakEventManager.DeliverEvent(Object sender, EventArgs args)
at System.Collections.Specialized.CollectionChangedEventManager.OnCollectionChanged(Object sender, NotifyCollectionChangedEventArgs args)
at System.Windows.Data.CollectionView.OnCollectionChanged(NotifyCollectionChangedEventArgs args)
at System.Windows.Data.ListCollectionView.RefreshOverride()
at System.Windows.Data.CollectionView.RefreshOrDefer()
at System.Windows.Data.ListCollectionView.ProcessCollectionChanged(NotifyCollectionChangedEventArgs args)
at System.Windows.Data.CollectionView.OnCollectionChanged(Object sender, NotifyCollectionChangedEventArgs args)
at System.Collections.ObjectModel.ObservableCollection`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
at System.Collections.ObjectModel.ObservableCollection`1.ClearItems()
at System.Collections.ObjectModel.Collection`1.Clear()
at CocoonV4.Modules.CocoonViewsVMs.ManageTemplateDekocastViewModel.SetAllowedDekos(IEnumerable`1 _NewAllowedDekos) in C:\Users\lkottmann\Documents\Visual Studio 2010\Projects\IAV-Cocoon\MAIN\CocoonV4\CocoonV4.Modules.RunningItem\CocoonViewsVMs\ManageTemplateDekocastViewModel.cs:line 83
at CocoonV4.Modules.CocoonViewsVMs.ManageTemplateDekocastViewModel.LoadTemplates(Nullable`1 param) in C:\Users\lkottmann\Documents\Visual Studio 2010\Projects\IAV-Cocoon\MAIN\CocoonV4\CocoonV4.Modules.RunningItem\CocoonViewsVMs\ManageTemplateDekocastViewModel.cs:line 128
at Microsoft.Practices.Prism.Commands.DelegateCommand`1.<>c__DisplayClass6.<.ctor>b__2(Object o)
at Microsoft.Practices.Prism.Commands.DelegateCommandBase.Execute(Object parameter)
at Microsoft.Practices.Prism.Commands.DelegateCommandBase.System.Windows.Input.ICommand.Execute(Object parameter)
at System.Windows.Interactivity.InvokeCommandAction.Invoke(Object parameter)
at System.Windows.Interactivity.TriggerBase.InvokeActions(Object parameter)
at System.Windows.Interactivity.EventTriggerBase.OnEvent(EventArgs eventArgs)
at System.Windows.Interactivity.EventTriggerBase.OnEventImpl(Object sender, EventArgs eventArgs)
at System.Windows.Controls.SelectionChangedEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
at System.Windows.UIElement.RaiseEvent(RoutedEventArgs e)
at System.Windows.Controls.ComboBox.OnSelectionChanged(SelectionChangedEventArgs e)
at System.Windows.Controls.Primitives.Selector.InvokeSelectionChanged(List`1 unselectedItems, List`1 selectedItems)
at System.Windows.Controls.Primitives.Selector.SelectionChanger.End()
at System.Windows.Controls.Primitives.Selector.SelectionChanger.SelectJustThisItem(Object item, Boolean assumeInItemsCollection)
at System.Windows.Controls.ComboBox.NotifyComboBoxItemMouseUp(ComboBoxItem comboBoxItem)
at System.Windows.Controls.ComboBoxItem.OnMouseLeftButtonUp(MouseButtonEventArgs e)
at System.Windows.UIElement.OnMouseLeftButtonUpThunk(Object sender, MouseButtonEventArgs e)
at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.ReRaiseEventAs(DependencyObject sender, RoutedEventArgs args, RoutedEvent newEvent)
at System.Windows.UIElement.OnMouseUpThunk(Object sender, MouseButtonEventArgs e)
at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
at System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)
at System.Windows.Input.InputManager.ProcessStagingArea()
at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at System.Windows.Interop.HwndSource.InputFilterMessage(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)
at System.Windows.Threading.Dispatcher.InvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
at System.Windows.Application.RunDispatcher(Object ignore)
at System.Windows.Application.RunInternal(Window window)
at System.Windows.Application.Run(Window window)
at System.Windows.Application.Run()
at CocoonV4.App.Main() in C:\Users\lkottmann\Documents\Visual Studio 2010\Projects\IAV-Cocoon\MAIN\CocoonV4\CocoonV4\obj\x86\Debug\App.g.cs:line 0
at System.AppDomain._nExecuteAssembly(RuntimeAssembly 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, Boolean ignoreSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
More EDIT:
I isolated the problem to a single ComboBox declarated as follow:
<custom:CComboBox x:Name="cmbFirstDko"
ItemsSource="{Binding Path=DataContext.MyFirstCollection, ElementName=myViewName}"
SelectedValue="{Binding anObjectID, Mode=TwoWay}"
SelectedValuePath="anObjectID">
Please note that the anObjectID property in SelectedValue comes from the ListView's DataContext (this ComboBox is displaying part of an item of that ListView), whereas the anObjectID in SelectedValuePath refers to a property that each item in DataContext.MyFirstCollection has.
This allows me to select a different ComboBoxItem for each element of the ListView.
I hope my explanation is clear, otherwise tell me in the comments and i'll try to clarify.
Breakthrough:
The ComboBoxes have their DataContext set to {DisconnectedItem}, this is the result of the work of so-called SentinelObjects which intervene when there's a binding between 2 collections, as in my example.
It is actually officialy a bug of the framework, and it has been fixed for the next version, see this MS Bug Page
Does anyone know of a workaround?
EDIT:
There used to be an answer linking to my blog, but while I move it people downvoted the answer. I got sick of it so now it'll be back when it's ready.
No need to call RaisePropertyChanged for MyObsCollection, because ObservableCollection internal implements INotifiyProperty Changed.
I think it is Crashing while assign the value(during set call), this will happen when you try to assign a collection of one type collection of another type. You have to create object of the MyCustomType and should be added to the MyObsCollection instead of directly assigning a collection of different type to MyObsCollection
It would be great if could post the entire code or piece of code where u assign the or add objects to MyObsCollection
I've the same problem just now, and after I remove the static-ressource Style on the ItemContainerStyle and define it directly beneath ListBox, the problem went away.
I had x:Name property on the elements in DataTemplate, and since I deleted them, the compilator didn't make it at all, probably. So I changed a way at all to make it sense.
Hope this small trick will help you !
I have several similar comboboxes with custom templates that display one custom control on the dropdown. Suddenly one of those controls have broken and they give me the following error when I open the combobox.
Message: Unhandled Error in Silverlight 2 Application Error 0x17F8. Debugging resource strings are unavailable. See http://go.microsoft.com/fwlink/?linkid=106663&Version=4.0.50401.0&File=mscorrc.dll&Key=0x17F8 at <INSERT_NAMESPACE>.ComboBox_DropDownOpened(Object sender, EventArgs e)
at System.Windows.Controls.ComboBox.OnDropDownOpened(EventArgs e)
at System.Windows.Controls.ComboBox.OnIsDropDownOpenChanged(Boolean isDropDownOpen)
at System.Windows.Controls.ComboBox.OnIsDropDownOpenChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
at System.Windows.DependencyObject.RaisePropertyChangeNotifications(DependencyProperty dp, Object oldValue, Object newValue)
at System.Windows.DependencyObject.UpdateEffectiveValue(DependencyProperty property, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, ValueOperation operation)
at System.Windows.DependencyObject.SetValueInternal(DependencyProperty dp, Object value, Boolean allowReadOnlySet)
at System.Windows.DependencyObject.SetValue(DependencyProperty property, Boolean b)
at System.Windows.Controls.ComboBox.ElementDropDownToggle_Click(Object sender, RoutedEventArgs e)
at System.Windows.Controls.Primitives.ButtonBase.OnClick()
at System.Windows.Controls.Primitives.ToggleButton.OnClick()
at System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)
at System.Windows.Controls.Control.OnMouseLeftButtonUp(Control ctrl, EventArgs e)
at MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, String eventName)
Line: 1
Char: 1
Code: 0
As you can see this only happens in deployed release versions and on the machines with no development environments. The same release version (and debug version) is working on my development machine.
I wrapped everything on the DropDownOpened event handler inside a try-catch-block to get more information but the catch doesn't fire at all.
I tried to Google the error but so far haven't found anything that would be helpful. Any advice how to start solving this? Could this be related to Silverlight runtime version or something that should be installed on the release machines as well?
I managed to solve the issue. I installed Developer Runtime to the machine for the hope that it would reveal better error message from the Exception. And it did! The issue was in the code of the control that was being displayed in the combobox dropdown. I fixed the bug and it's now working fine. Apparently even the strangest error message can mean the simplest thing :)
I wonder if there is a drawback on having the developer runtime instead of the standard runtime?