Use CollectionViewSource with TabControl - wpf

Question

I'm trying to group and display the items of an ObservableCollection, just by using XAML code. It works well using a simple CollectionViewSource and a ListBox[1].
Actually, I would prefer to display the group's content in a tabcontrol. Google led me to the following social.msdn article wich presents a workaround to display the groups as a TabControl using code behind:
https://social.msdn.microsoft.com/Forums/vstudio/en-US/e073f275-0826-4fca-b9da-e310ccf1713e/wpf-grouping?forum=wpf
However, as I'm using MVVM and must rely on xaml only, I can't get it to work. Actually, the CollectionViewSource populates the groups (the TabControl shows the correct tabItemHeaders), but clicking on any of these TabItems freezes the application. Here's what I've tried:
<StackPanel x:Key="ModulSelectInputParameterView">
<StackPanel.Resources>
<CollectionViewSource x:Key="cvs" x:Name="collectionViewSource" Source="{Binding ReferencedLmtItem.ModulInputParameterCollection }">
<CollectionViewSource.GroupDescriptions>
<PropertyGroupDescription PropertyName="Category"/>
</CollectionViewSource.GroupDescriptions>
</CollectionViewSource>
</StackPanel.Resources>
<Grid >
<TabControl ItemsSource="{Binding Source={StaticResource cvs}, Path=Groups, Mode=OneWay}" DataContext="{Binding Source={StaticResource cvs}, Mode=OneWay}">
<!-- First Level -->
<TabControl.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Name}"/>
</DataTemplate>
</TabControl.ItemTemplate>
<TabControl.ContentTemplate>
<DataTemplate>
<ListBox ItemsSource="{Binding Items}">
Second Level
<ListBox.ItemTemplate>
<DataTemplate>
<Expander Header="{Binding Name}">
<ListBox ItemsSource="{Binding Items}">
The Item of the Collection
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Key}"/>
<TextBlock Text=" - "/>
<TextBlock Text="{Binding Value.Comment}"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Expander>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</DataTemplate>
</TabControl.ContentTemplate>
</TabControl>
</Grid>
</StackPanel>
[1]: This peace of xaml does work as expected, but uses a wrappanel to display groups contents:
<StackPanel x:Key="ModulSelectInputParameterView">
<StackPanel.Resources>
<CollectionViewSource x:Key="cvs" x:Name="collectionViewSource" Source="{Binding ReferencedLmtItem.ModulInputParameterCollection }">
<CollectionViewSource.GroupDescriptions>
<PropertyGroupDescription PropertyName="Category"/>
</CollectionViewSource.GroupDescriptions>
</CollectionViewSource>
</StackPanel.Resources>
<ListBox ItemsSource="{Binding Source={StaticResource cvs}}" VerticalContentAlignment="Top" ItemContainerStyle="{StaticResource ModulSelectInputParameterListBoxItemContainerStyle}" ScrollViewer.HorizontalScrollBarVisibility="Disabled">
<ListBox.GroupStyle>
<GroupStyle>
<GroupStyle.HeaderTemplate>
<DataTemplate>
<Border BorderBrush="DarkGray" BorderThickness="2" Margin="2">
<TextBlock FontWeight="Bold" FontSize="14" Text="{Binding Path=Name}" HorizontalAlignment="Center" MinWidth="100"/>
</Border>
</DataTemplate>
</GroupStyle.HeaderTemplate>
<GroupStyle.Panel>
<ItemsPanelTemplate>
<WrapPanel Orientation="Horizontal" Margin="2"/>
</ItemsPanelTemplate>
</GroupStyle.Panel>
<GroupStyle.ContainerStyle>
<Style TargetType="{x:Type GroupItem}" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type GroupItem}">
<Border BorderThickness="2" BorderBrush="DarkGray">
<StackPanel>
<ContentPresenter Content="{TemplateBinding ContentControl.Content}" ContentTemplate="{TemplateBinding ContentControl.ContentTemplate}" ContentStringFormat="{TemplateBinding ContentControl.ContentStringFormat}" />
<ItemsPresenter Margin="2,0,2,2" />
</StackPanel>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</GroupStyle.ContainerStyle>
</GroupStyle>
</ListBox.GroupStyle>
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<WrapPanel IsItemsHost="True" Orientation="Vertical" VerticalAlignment="Top"/>
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
</ListBox>
</StackPanel>

Answer 1

I think there's something wrong with your binding your code should work.
To get the same items in both ListBoxes try to bind the second ListBox Itemssource to the first ListBox Itemssource like this :
<ListBox ItemsSource="{Binding Items}" Name="ListBox">
<ListBox.ItemTemplate>
<DataTemplate>
<Expander Header="{Binding Key}">
<ListBox ItemsSource="{Binding ItemsSource, ElementName=ListBox}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Key}"/>
<TextBlock Text=" - "/>
<TextBlock Text="{Binding Value}"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Expander>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>

Answer 2

Thanks to Joh who helped with the appropriate DataBinding. However, the reason was totally different, a quick and dirty solution is given below[1]:
Basically, I was missing that the above mentioned tab control is nested within an outer Tab Control in my main window. I am not toally sure if the following description is entirely correct[1], but to my mind the reason is the following:
The outer TabControl uses a style to display its content. This content applies to a ViewModel which holds the above mentioned observable collection, which in turn should be the ItemsSource of the CollectionViewSource that feeds the inner tabControl with the groups.
As I have defined this style only in the outer TabControl.Resources, and missed to define a separate style for the inner tab Control, the inner tabcontrol inherits the outer style and tries to display its data using the same content.
This content is again another inner tabControl, which calls another inner tabControl and so on.
[1] Defining an empty style in the inenr tabControl.Resources solved the problem:
<TabControl.Resources>
<Style TargetType="TabItem">
</Style>
</TabControl.Resources>
I would be happy if someone could confirm this idea or provide some links to well known issues with shared styles in nested controls.