WPF Bindings TreeView Issue with view

Question

I'm simply trying to bind my tree view in xaml but for some reason the list does not seem to be showing, I have attached the code. Any help would be great.

Many thanks

class Item
{
    public string Header { get; set; }
    public List<string> TreeItems { get; set; }
    public List<Item> SubItems { get; set; }
}

this is the view model

    public StoreLibraryViewModel()
    {
        this.DisplayName = "hierarchy Library";
        TreeItems = new ObservableCollection<Item>();

        string[] data = new string[]{
            "Warwick","Birmingham",
        };
        Item item = new Item()
        {
            Header = "Region",
            TreeItems = new List<string>(data)
        };

        TreeItems.Add(new Item()
        {
            Header = "Region 1",
            SubItems = new List<Item>(new Item[] { item }),
            TreeItems = new List<string>(data)
        });
        TreeItems.Add(new Item()
        {
            Header = "Region 2",
            SubItems = new List<Item>(new Item[] { item }),
            TreeItems = new List<string>(data)
        });

        TreeItems.Add(new Item()
        {
            Header = "Region 3",
            SubItems = new List<Item>(new Item[] { item }),
            TreeItems = new List<string>(data)
        });
    }
    ObservableCollection<Item> TreeItems { get; set; }

this is the XAML

TreeView ItemsSource="{Binding TreeItems}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
        <TreeView.ItemTemplate>
            <HierarchicalDataTemplate ItemsSource="{Binding SubItems}">
                <Expander Header="{Binding Header}">
                    <ItemsControl Margin="25,0,0,0" ItemsSource="{Binding TreeItems}" />
                </Expander>
            </HierarchicalDataTemplate>
        </TreeView.ItemTemplate>
    </TreeView>

All I seem to be displaying is a empty tree view, any assistance would be greatly appreciated.

Many Thanks

Answer 1

You just have to assign your datacontext in the xaml code like this:

<Window ....
        xmlns:local="clr-namespace:myStoreLibraryViewModelNameSpace"
        ....
        />
     <Window.DataContext>
        <local:StoreLibraryViewModel />
     </Window.DataContext>
   ....

where myStoreLibraryViewModelNameSpace is the namespace in which StoreLibraryViewModel is located

Answer 2

You should add:

DataContext = new StoreLibraryViewModel();

Then you need to make your ObservableCollection TreeItems { get; set; } public

public ObservableCollection<Item> TreeItems { get; set; }

Here is the result