InvalidOperationException: Failed to compare two elements in the array.

[Jonathon]

Hi,

I decided to make a new thread for this issue:

My GridView is a collection of IActivity which is an interface I made that 3 classes implement. This only happens when I try to adda new activity to the grid when it is sorted. When the Grid is not sorted, the activity is added to the grid. This is the error:

{System.InvalidOperationException: Failed to compare two elements in the array. ---> System.InvalidCastException: Unable to cast object of type 'FirstActivityViewModel' to type 'SecondActivityViewModel'.
   at Telerik.Windows.Data.FuncExtensions.<>c__DisplayClass1`2.<ToUntypedFunc>b__0(Object item)
   at Telerik.Windows.Data.FunctionComparer.Compare(Object x, Object y)
   at System.Collections.Generic.ArraySortHelper`1.InternalBinarySearch(T[] array, Int32 index, Int32 length, T value, IComparer`1 comparer)
   at System.Collections.Generic.ArraySortHelper`1.BinarySearch(T[] array, Int32 index, Int32 length, T value, IComparer`1 comparer)
   --- End of inner exception stack trace ---
   at System.Collections.Generic.ArraySortHelper`1.BinarySearch(T[] array, Int32 index, Int32 length, T value, IComparer`1 comparer)
   at System.Array.BinarySearch[T](T[] array, Int32 index, Int32 length, T value, IComparer`1 comparer)
   at System.Collections.Generic.List`1.BinarySearch(Int32 index, Int32 count, T item, IComparer`1 comparer)
   at System.Collections.Generic.List`1.BinarySearch(T item, IComparer`1 comparer)
   at Telerik.Windows.Data.KeyedCollection.IndexOf(Object value)
   at Telerik.Windows.Data.QueryableCollectionView.InternalIndexOf(Object item)
   at Telerik.Windows.Data.QueryableCollectionView.IndexOf(Object item)
   at Telerik.Windows.Data.DataItemCollection.IndexOf(Object value)
   at Telerik.Windows.Controls.DataControl.ItemCoerce(DependencyObject d, Object baseValue)
   at Telerik.Windows.PropertyMetadata.DoCoercion(Func`3 areValuesEqual, DependencyObject d, DependencyProperty dp, CoerceValueCallback coerceCallback, Object defaultBaseValue, Boolean forceNewBaseValue, Boolean& isReentrantImplicitCoercion)
   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 GalaSoft.MvvmLight.ViewModelBase.RaisePropertyChanged(String propertyName)
   at Telerik.Windows.Controls.RadSplitButton.ExecuteCommand()
   at Telerik.Windows.Controls.RadSplitButton.OnClick()
   at Telerik.Windows.Controls.RadSplitButton.ActionButton_Click(Object sender, RoutedEventArgs e)
   at System.Windows.Controls.Primitives.ButtonBase.OnClick()
   at System.Windows.Controls.Button.OnClick()
   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)}

Is there a fix for this?

Thanks,

Jonathon

[Christian Burkhardt]

I have exactly the same error. It wasn't there in the previous version of the gridview.

[Christian Burkhardt]

I now compiled the sources and debugged it. The problem is in the FuncExtensions class, specifically this method:

        public static Func<object, object> ToUntypedFunc<T, TResult>(Func<T, TResult> func)
        {
            return item => func.Invoke((T) item);
        }

It tries to cast to T, but if you have items of multiple types in the gridview, it will be called once for the "wrong" type of object and try to cast it to T and fail.

Looking forward to a fix, as this actually broke my app :(

[Vlad]

Hi,

 Will post more info about your scenario? What is your current grid version and what was the previous version?

Greetings,
Vlad
the Telerik team

[Jonathon]

I'm currently using 2011.3.1116.1040. 

[Luc]

Same error using  2011.3 1220 for SL5.. Any fix to this sortdescriptor issue

[Vlad]

Hi,

 Please open support ticket and send us an example project where we can reproduce and debug the exception. 

Kind regards,
Vlad
the Telerik team

[Josh Eastburn]

Has there been a resolution to this problem?
I am experiencing the same problem in my application running 2011.2.920.1040.

Thank you.

[Josh Eastburn]

To be more precise about the error I am receiving, the exception is due to a NullReferenceException:

System.InvalidOperationException: Failed to compare two elements in the array. ---> System.NullReferenceException: Object reference not set to an instance of an object.

The exception is thrown when I try to sort on a column that sorts by a property of a related object that is NULL for an item.  However, I do not get the exception the first time when sorting by this column.  Only after repeatedly changing the sort order on other columns will the error occur.

The GridViewDataColumn with the problem:

<telerik:GridViewDataColumn IsReadOnly="True" DataMemberBinding="{Binding Vendoremployee.VendorEmployeeName}" SortMemberPath="Vendoremployee.FirstName" />

I looked at the data and the Vendoremployee property is null for two of the rows.  But why does this exception not occur the first time I sort on this column?
Is there a way to change the Sort behavior to trap this exception?