Using multiple Treeview objects with the same (but cloned) itemssource - wpf

Question

So, I have a listview with different datatemplates as seen here:
<ListView Panel.ZIndex="0" x:Name="FilterList" Margin="10,0" Grid.Row="2"
Grid.ColumnSpan="3" Background="White" ItemTemplateSelector="{StaticResource
ReportFilterTemplateSelector}" ItemsSource="{Binding reportParameters,
Mode=TwoWay}" ScrollViewer.CanContentScroll="False">
One of my sample datatemplates can be seen below. Everything shows up great. My problem, is that for this (and other) datatemplates, I can have multiple instances of the same one. In this particular instance, the treeview itemssource is bound to DataContext.OfficeListText to populate all the elements.
<DataTemplate x:Key="office">
<Grid MinHeight="35" MaxHeight="250">
<Grid.RowDefinitions>
<RowDefinition/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="100"/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<TextBlock Text="{Binding rpName}" VerticalAlignment="Center" Grid.Row="0" Grid.Column="0" />
<Expander HorizontalAlignment="Stretch" Grid.Row="0" Grid.Column="1"
Header="{Binding Path=DataContext.OfficeListText, RelativeSource=
{RelativeSource FindAncestor, AncestorType={x:Type UserControl}}}"
VerticalAlignment="Top" ExpandDirection="Down">
<TreeView Tag="{Binding rpParameter}" HorizontalAlignment="Stretch"
VerticalAlignment="Stretch" ItemsSource="{Binding
Path=DataContext.OfficeList, RelativeSource={RelativeSource
FindAncestor, AncestorType={x:Type UserControl}}, Mode=TwoWay}"
ItemTemplate="{StaticResource CheckBoxItemTemplate}"
ItemContainerStyle="{StaticResource TreeViewItemStyle}"/>
</Expander>
</Grid>
</DataTemplate>
The main problem with this is one, for instance, if I select an office in say the first treeview, the 2nd treeview shows the same. Essentially I want them to have the same itemssource initially but have separate instances. Since they are generated dynamically that is where I'm getting stuck. Any help would be appreciated.
I'm not sure what other code would be necessary, since I'm sure most of it will be irreverent based on what I'll need to do to make this work, but if you would like more I will gladly provide. Thanks!

Answer 1

Currently your TreeView binds to a single instance of OfficeList that belongs to your UserControl's DataContext. This means that every TreeView points to the same list. If I understand your question correctly, what you really want is to have a different instance of OfficeList for each TreeView.
I don't recommend instantiating a new OfficeList each time the DataTemplate is applied to a reportParameter. You could do that with a ValueConverter, but it would be pretty hacky.
The cleaner solution would be to have a class that contains the data for your reportParameter, plus an instance of OfficeList, and then bind to instances of that class instead of binding to the UserControl. Depending on how the reportParameters are structured (I am going to assume that reportParameters is a list of objects of type ReportParameter), there are two ways you might want to do this:
1) If ReportParameter is a ViewModel, you can simply add an OfficeList property to the ReportParameter class, and initialize it when you instantiate each ReportParameter.
Then your TreeView would look like this:
<TreeView Tag="{Binding rpParameter}" HorizontalAlignment="Stretch"
VerticalAlignment="Stretch" ItemsSource="{Binding Path=OfficeList, Mode=TwoWay}"
ItemTemplate="{StaticResource CheckBoxItemTemplate}"
ItemContainerStyle="{StaticResource TreeViewItemStyle}"/>
2) If ReportParameter is not a ViewModel (and thus it would not be appropriate to add an OfficeList parameter), then create a new class called something like ReportParameterViewModel that contains 2 properties: ReportParameter and OfficeList. Instead of binding your ListView to a list of ReportParameter, bind to a list of ReportParameterViewModel.
Then your ListView will look something like this:
<ListView Panel.ZIndex="0" x:Name="FilterList" Margin="10,0" Grid.Row="2"
Grid.ColumnSpan="3" Background="White" ItemTemplateSelector="{StaticResource
ReportFilterTemplateSelector}" ItemsSource="{Binding reportParameterViewModels,
Mode=TwoWay}" ScrollViewer.CanContentScroll="False">
Your TextBlock will look like this:
<TextBlock Text="{Binding ReportParameter.rpName}" VerticalAlignment="Center" Grid.Row="0" Grid.Column="0" />
Your TreeView will look like this:
<TreeView Tag="{Binding rpParameter}" HorizontalAlignment="Stretch"
VerticalAlignment="Stretch" ItemsSource="{Binding Path=OfficeList, Mode=TwoWay}"
ItemTemplate="{StaticResource CheckBoxItemTemplate}"
ItemContainerStyle="{StaticResource TreeViewItemStyle}"/>