System.Windows.Data Error = 2

[Anthony]

I'm seeing an odd error with the grouping in the RadGridView. It's worth pointing out that the data is being displayed and grouped properly despite the error. However, I still want it resolved.

System.Windows.Data Error: 2 : Cannot find governing FrameworkElement or FrameworkContentElement for target element. BindingExpression:Path=Columns[ContactType]; DataItem=null; target element is 'ColumnGroupDescriptor' (HashCode=34214014); target property is 'Column' (type 'GridViewColumn')

Below is the relevant portion of my XAML. The extra columns have been elided as is the rest of the visual tree. I get the same problem if it's in different parts of the visual tree and even with just the one column.

​<telerik:RadGridView x:Name="ContactsGridView"
                        ItemsSource="{Binding Employee.Contacts}">
    <telerik:RadGridView.Columns>
        <telerik:GridViewComboBoxColumn Header="Type" UniqueName="TypeColumn"
                                        ItemsSource="{Binding ContactTypesView}"
                                        DataMemberBinding="{Binding ContactTypeId}"
                                        SelectedValueMemberPath="Id" DisplayMemberPath="TypeName"
                                        EditTriggers="CellClick" ShowColumnWhenGrouped="False" />
    </telerik:RadGridView.Columns>
    <telerik:RadGridView.GroupDescriptors>
        <telerik:ColumnGroupDescriptor Column="{Binding Columns[\TypeColumn\], ElementName=ContactsGridView}"
                                        SortDirection="Ascending" />
    </telerik:RadGridView.GroupDescriptors>
</telerik:RadGridView>

I have a style that governs the several grids in my window. Here is that XAML:

<Style TargetType="{x:Type telerik:RadGridView}">
    <Setter Property="BorderThickness" Value="0" />
    <Setter Property="GridLinesVisibility" Value="None" />
    <Setter Property="ShowGroupPanel" Value="False" />
    <Setter Property="RowIndicatorVisibility" Value="Collapsed" />
    <Setter Property="RowDetailsVisibilityMode" Value="Collapsed" />
    <Setter Property="AutoGenerateColumns" Value="False" />
    <Setter Property="CanUserFreezeColumns" Value="False" />
    <Setter Property="SelectionUnit" Value="FullRow" />
    <Setter Property="AutoExpandGroups" Value="True" />
    <Setter Property="GroupRenderMode" Value="Flat" />
</Style>

Any ideas of what might be causing this error? I created a stripped down solution and couldn't duplicate the error message.

[Boris]

Hello Anthony,

We tried to reproduce the mentioned BindingExpressions. However, we were unsuccessful. In order to reproduce the error, could you please modify the attached sample project and send it back to us so that we can debug it on our side ?


Regards,
Boris Penev
Telerik

 

 

[Anthony]

Odd. My previous reply didn't get posted. In it I had indicated that I hadn't been able to reproduce it. Tonight I messed with it some more and I was able to get the magical combination without pasting my entire application.

Essentially, Error: 2:Cannot find governing FrameworkElement or FrameworkContentElement for target element occurs when the RadGridView is inside a RadExpander.

<telerik:RadExpander>
     <telerik:RadGridView ...>
          ...
     </telerik:RadGridView>
</telerik:RadExpander>

[Boris]

Hello Anthony,

We were successful in reproducing the issue. 
The reason for this issue is that the Column property of the ColumnGroupDescriptor is bound to "{Binding Columns[\Country\], ElementName=pilotsGrid}". This is an issue because the WPF Framework reads initially through the XAML and at that point the pilotsGrid still does not exist (RadExpander is not yet expanded). In order to resolve this you can use a GroupDescriptor instead of the ColumnGroupDescriptor one.

<telerik:RadGridView.GroupDescriptors>
        <telerik:GroupDescriptor Member="CountryId" SortDirection="Ascending" />
</telerik:RadGridView.GroupDescriptors>

Also, I attached a sample project that demonstrates the suggested approach.

I hope this helps.


Regards,
Boris Penev
Telerik

 

 

[Anthony]

Thanks. That works great. I wasn't aware of the GroupDescriptor.

I was a little concerned about it working, because my member is a key value and not a discrete value (and I obviously don't want to show the key value). However, this uses the rules of the column to show the name of the contact type just like a column.

[Aliaster]

Firstly, this message will not do affect your binding part, if you want to know the reason, I think you could add a Converter to debug your binding: You could also try the Windows Data Recovery Tool by SysInfoTools a leading software firm developing high end software utilities