Question

I have two classes,

public class BookItem
{
    public string BookID            { get; set; }
    public string ItemID            { get; set; }
    public Item Item                { get; set; }   
    public ItemType Type            { get; set; }
    public string ParentID          { get; set; }
    public string BoxID             { get; set; }
    public string StyleID           { get; set; }
    public string NotesID           { get; set; }
    public string Code_XAML         { get; set; }
    public string Description_XAML      { get; set; }
    public CompositeCollection SubItems { get; set; }
}

public class Item : ClaunchBaseClass
{
    public string ItemID        { get; set; }
    public int    Type          { get; set; }
    public string Code          { get; set; }
    public string Description   { get; set; }
    private BookList _books = new BookList();
    public BookList Books       { get {return _books;} set { _books = value; }}
}

and I’ve created the following XAML:

<pre>    
<TreeView Name="tvList" Grid.Row="2" MouseDoubleClick="tvList_MouseDoubleClick">
    <TreeView.ItemTemplate>
        <HierarchicalDataTemplate DataType="x:Type j:BookItem" ItemsSource="{Binding SubMenu}">
            <Grid>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="50"/>
                    <ColumnDefinition Width="*"/>
                </Grid.ColumnDefinitions>
                <TextBlock Text="{Binding Item.Code}" Grid.Column="0" />
                <TextBlock Text="{Binding Item.Description}" Grid.Column="1"/>
            </Grid>
        </HierarchicalDataTemplate>
    </TreeView.ItemTemplate>
</TreeView>
<code>

This XAML binds the treeview items to the collection of book items and displays the Item subclass’s Description and Code, the treeview populates and displays correctly but now I want to sort the treeview on either Item.Code or Item.Description and have tried the following with no results:

<pre> 
var bookItemsSort = CollectionViewSource.GetDefaultView(_bookItemList) as ListCollectionView;
tvList.ItemsSource = _bookItemList;         //bind the book items to the treeview
bookItemsSort.SortDescriptions.Clear();
bookItemsSort.SortDescriptions.Add(new SortDescription(sort, Ascending));
<code>

I’ve had this code work correctly for other treeviews so I can only guess it is a problem with binding to a subclass.

Answer 1

While the answers here provided partial answers to my question, none of them gave the answer that I needed.

The most sensible solution for this problem was to write my own object comparer for this object type and sort the underlying list and then re-bind the new list to the treeview. This allowed for comparing sublasses at any nested level which I couldn’t make work any other way 🙂