Null ref on calendar column

[Chris]

I received a stack trace from a user containing the following message:

[Arg_NullReferenceException]
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=5.0.61118.00&File=mscorlib.dll&Key=Arg_NullReferenceException
Type: System.NullReferenceException
at Telerik.Windows.WeakReferenceList`1.WeakReferenceEnumerator.get_Current()
at Telerik.Windows.Controls.SelectionChanger`1.SynchronizeInternalSelection()
at Telerik.Windows.Controls.SelectionChanger`1.End()
at Telerik.Windows.Controls.SelectionChanger`1.AddJustThis(T item)
at Telerik.Windows.Controls.RadCalendar.AddToSelection(DateTime selectedDate, Boolean controlKeyDown, Boolean shiftKeyDown)
at Telerik.Windows.Controls.RadCalendar.Select(DateTime selectedDate, Boolean forceSelection)
at Telerik.Windows.Controls.Calendar.CalendarView.AddDate(Object sender)
at Telerik.Windows.Controls.Calendar.CalendarView.HandleMouseEvents(Object sender, MouseButtonEventArgs e)
at Telerik.Windows.Controls.Calendar.CalendarView.CalendarButtonMouseLeftButtonDown(Object sender, MouseButtonEventArgs 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, Int32 actualArgsTypeIndex, String eventName, UInt32 flags)

Has this issue been investigated / resolved? I believe the user was trying to change a date field using a grid cell using a date.

[Yana]

Hi Adam,

I am afraid that the provided information is not enough for us to reproduce the issue, can you please send us a simple runnable project demonstrating the problem? You should open a support ticket and attach it there.

Thanks in advance.

All the best,
Yana
the Telerik team

[Matt]

Unfortunately this was not something we witnessed or could reproduce but rather was something we encountered in an exception log and were hoping you had resolved since then. It appears to be an issue with garbage collection due to the null ref and Weak Listener usage so it's highly unlikely that any project that could be provided could reproduce this issue consistently anyway.

[Elena Sinelnikova]

We have experienced following intermittent errors, that seem to be similar to yours:

Error1:

[Arg_NullReferenceException]
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=4.0.60310.0&File=mscorlib.dll&Key=Arg_NullReferenceException; StackTrace:    at Telerik.Windows.WeakReferenceList`1.CopyTo(T[] array, Int32 arrayIndex)
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at Telerik.Windows.Controls.SelectionChanger`1.BuildSelectionChangedEventArgs()
   at Telerik.Windows.Controls.SelectionChanger`1.ClearItems()
   at System.Collections.ObjectModel.Collection`1.Clear()
   at Telerik.Windows.Controls.RadCalendar.OnSelectedDateChanged(DependencyObject sender, 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.RefreshExpression(DependencyProperty dp)
   at System.Windows.Data.BindingExpression.SendDataToTarget()
   at System.Windows.Data.BindingExpression.SourcePropertyChanged(PropertyPathListener sender, PropertyPathChangedEventArgs args)
   at System.Windows.PropertyPathListener.RaisePropertyPathStepChanged(PropertyPathStep source)
   at System.Windows.PropertyAccessPathStep.RaisePropertyPathStepChanged(PropertyListener source)
   at System.Windows.DependencyPropertyListener.SourcePropertyChanged(DependencyObject sender, DependencyProperty dp)
   at System.Windows.Data.WeakDependencyPropertyChangedListener.SourcePropertyChanged(DependencyObject sender, DependencyProperty dp)
   at System.Windows.DPChangedEventHandler.Invoke(DependencyObject sender, DependencyProperty dp)
   at System.Windows.DependencyObject.OnPropertyChanged(DependencyProperty dp)
   at System.Windows.FrameworkElement.OnPropertyChanged(DependencyProperty dp)
   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 Telerik.Windows.Controls.RadDateTimePicker.OnSelectedValueChanged()
   at Telerik.Windows.Controls.RadDateTimePicker.OnSelectedValueChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
   at Telerik.Windows.PropertyMetadata.PropertyChangeHook.OnPropertyChanged(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.RefreshExpression(DependencyProperty dp)
   at System.Windows.Data.BindingExpression.SendDataToTarget()
   at System.Windows.Data.BindingExpression.SourcePropertyChanged(PropertyPathListener sender, PropertyPathChangedEventArgs args)
   at System.Windows.PropertyPathListener.RaisePropertyPathStepChanged(PropertyPathStep source)
   at System.Windows.PropertyAccessPathStep.RaisePropertyPathStepChanged(PropertyListener source)
   at System.Windows.CLRPropertyListener.SourcePropertyChanged(Object sender, PropertyChangedEventArgs args)
   at System.Windows.Data.WeakPropertyChangedListener.PropertyChangedCallback(Object sender, PropertyChangedEventArgs args)
   at System.ComponentModel.PropertyChangedEventHandler.Invoke(Object sender, PropertyChangedEventArgs e)
   at EPS_PICU.ViewModels.ViewModelBase.OnPropertyChanged(String propertyName, Boolean dirty)
   at EPS_PICU.ViewModels.PICSearchViewModel.set_CreFrom(Nullable`1 value)
   at EPS_PICU.ViewModels.PICSearchViewModel.OnReset(Object parameter)
   at EPS_PICU.ViewModels.RelayCommand.Execute(Object parameter)
   at Telerik.Windows.Controls.RadButton.ExecuteCommand()
   at Telerik.Windows.Controls.RadButton.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, Int32 actualArgsTypeIndex, String eventName)

Error 2:

[Arg_NullReferenceException]
Arguments: a
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=4.0.60310.0&File=mscorlib.dll&Key=Arg_NullReferenceException; StackTrace:    at Telerik.Windows.WeakReferenceList`1.CopyTo(T[] array, Int32 arrayIndex)
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at Telerik.Windows.Controls.SelectionChanger`1.BuildSelectionChangedEventArgs()
   at Telerik.Windows.Controls.SelectionChanger`1.ClearItems()
   at System.Collections.ObjectModel.Collection`1.Clear()
   at Telerik.Windows.Controls.RadCalendar.OnSelectedDateChanged(DependencyObject sender, 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.RefreshExpression(DependencyProperty dp)
   at System.Windows.Data.BindingExpression.SendDataToTarget()
   at System.Windows.Data.BindingExpression.SourcePropertyChanged(PropertyPathListener sender, PropertyPathChangedEventArgs args)
   at System.Windows.PropertyPathListener.RaisePropertyPathStepChanged(PropertyPathStep source)
   at System.Windows.PropertyAccessPathStep.RaisePropertyPathStepChanged(PropertyListener source)
   at System.Windows.DependencyPropertyListener.SourcePropertyChanged(DependencyObject sender, DependencyProperty dp)
   at System.Windows.Data.WeakDependencyPropertyChangedListener.SourcePropertyChanged(DependencyObject sender, DependencyProperty dp)
   at System.Windows.DPChangedEventHandler.Invoke(DependencyObject sender, DependencyProperty dp)
   at System.Windows.DependencyObject.OnPropertyChanged(DependencyProperty dp)
   at System.Windows.FrameworkElement.OnPropertyChanged(DependencyProperty dp)
   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.RefreshExpression(DependencyProperty dp)
   at System.Windows.Data.BindingExpression.SendDataToTarget()
   at System.Windows.Data.BindingExpression.SourceAcquired()
   at System.Windows.Data.BindingExpression.System.Windows.IDataContextChangedListener.OnDataContextChanged(Object sender, DataContextChangedEventArgs e)
   at System.Windows.Data.BindingExpression.DataContextChanged(Object sender, DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnAncestorDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.NotifyDataContextChanged(DataContextChangedEventArgs e)
   at System.Windows.FrameworkElement.OnPropertyChanged(DependencyProperty dp)
   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.RefreshExpression(DependencyProperty dp)
   at System.Windows.Data.BindingExpression.SendDataToTarget()
   at System.Windows.Data.BindingExpression.SourcePropertyChanged(PropertyPathListener sender, PropertyPathChangedEventArgs args)
   at System.Windows.PropertyPathListener.RaisePropertyPathStepChanged(PropertyPathStep source)
   at System.Windows.PropertyAccessPathStep.RaisePropertyPathStepChanged(PropertyListener source)
   at System.Windows.CLRPropertyListener.SourcePropertyChanged(Object sender, PropertyChangedEventArgs args)
   at System.Windows.Data.WeakPropertyChangedListener.PropertyChangedCallback(Object sender, PropertyChangedEventArgs args)
   at System.ComponentModel.PropertyChangedEventHandler.Invoke(Object sender, PropertyChangedEventArgs e)
   at EPS_PICU.ViewModels.ViewModelBase.OnPropertyChanged(String propertyName, Boolean dirty)
   at EPS_PICU.ViewModels.PICApplicationViewModel.set_PICApplication(ApplicationForm value)
   at EPS_PICU.ViewModels.PICApplicationViewModel.Load(Object parameter)
   at EPS_PICU.Views.PICApplication..ctor()

[Ivo]

Hi,

We successfully reproduced similar issue at our side. We will do our best to fix it for one of the upcoming builds.

Thank you for your great feedback.

All the best,
Ivo
the Telerik team

[Ovidiu]

   We seem to encounter the same problem . Has any fix been released in future versions ?

[Ivo]

Hello Ovidiu,

We fixed a similar issue a couple of months ago, so you can download the latest version of RadControls for Silverlight and check it at your side.

Regards,
Ivo
the Telerik team