Checked Combobox inside DataTemplate which is inside Listbox DataTemplate - wpf

Question

I have a listbox and its data template. But in its DataTemplate i have CheckedCombobox DataTemplate. Wanted to know how to set the bindings. I have tried below things to get which are items checked in child element by each listbox item. Below is the code which is not working.
<ListBox
Name="ListLayers"
ItemsSource="{Binding LstDragList}"
Height="123"
Width="283"
SelectedIndex="{Binding SelectedRow, UpdateSourceTrigger=PropertyChanged, Mode=OneWayToSource}"
>
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<ComboBox
Name="childlayers"
Style="{StaticResource EditableCboStyle}"
ItemsSource="{Binding lstLayerModel}"
Text="{Binding SelectedLayers, UpdateSourceTrigger=PropertyChanged}"
ItemContainerStyle="{DynamicResource ComboboxItemContainerStyle}"
Width="200"
IsEditable="True"
IsReadOnly="False"
PreviewMouseLeftButtonDown="ComboBox_PreviewMouseLeftButtonDown"
>
<ComboBox.ItemTemplate>
<DataTemplate DataType="{x:Type local:Model}">
<CheckBox
VerticalAlignment="Center"
VerticalContentAlignment="Center"
IsChecked="{Binding IsChecked}"
Content="{Binding DisplayLayer}"
/>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
Models:
public class DragList : ObservableObject
{
public DragList()
{
_selectedLayers = string.Empty;
}
public string FileName { get; set; }
public ObservableCollection<Model> lstLayerModel { get; set; }
public string Text { get; set; }
private string _selectedLayers;
public string SelectedLayers
{
get { return _selectedLayers; }
set { SetAndNotify(ref _selectedLayers, value, () => this.SelectedLayers); }
}
private int _selectedLayerInx;
public int SelectedLayerInx
{
get { return _selectedLayerInx; }
set { SetAndNotify(ref _selectedLayerInx, value, () => this.SelectedLayerInx); }
}
}
my constructor viewmodel:
public ViewModel()
{
_lstLayers = new ObservableCollection<Model>();
mCheckedItems = new ObservableCollection<Model>();
_tempDragList = new List<DragList>();
_lstLayers.CollectionChanged += _lstLayers_CollectionChanged;
_lstLayers.Add(new Model
{
LayerName = "All",
LayerNumber = "",
IsChecked = true
});
_lstLayers.Add(new Model { LayerName = "Layer one", LayerNumber = "1", IsChecked = false });
_lstLayers.Add(new Model { LayerName = "Layer two", LayerNumber = "2", IsChecked = false });
_lstLayers.Add(new Model { LayerName = "Layer three", LayerNumber = "3", IsChecked = false });
_lstDragList = new List<DragList>();
_lstDragList.Add(new DragList { FileName = "Test", lstLayerModel = _lstLayers });
_lstDragList.Add(new DragList { FileName = "Test1", lstLayerModel = _lstLayers });
_tempDragList = _lstDragList;
}

Answer 1

It's because you need to use RelativeSource on the inner bindings to get the correct DataContext like so:
{Binding DataContext.SelectedRow, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListBox}}}
There are many other articles on RelativeSource here on SO that should provide you with that you need.