WPF: Custom collection ( List<Type>) databinding to a Listbox with Path filtering

Question

I have created a custom DataSourceProvider that provides a List<XmlNode> as a Query result.

By using the Path parameter, the resulting Listbox should contain the specified list of the property named in XmlNode

Path=Tag should populate the listbox with the Tag(s) contained in the List. But instead it populates the list with the first List-items Tag.

The question is why the Path parameter not retreives all Tag elements from the List but only the letters from the first list elements Tag.

---

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The Custom list is provided as a resource:

<Window.Resources>

    <classes:Custom_XmlProvider x:Key="txtProvider" Path="name" />

</Window.Resources>

The ListBox binds to the resource with the Path=Tag:

 <ListBox Grid.Row="1" ItemsSource="{Binding Path=Tag, Source={ StaticResource txtProvider}}"
             DockPanel.Dock="Bottom">
        <ListBox.ItemTemplate>
            <DataTemplate>
                <StackPanel Orientation="Horizontal">
                    <Label Content="{Binding}" FontFamily="Arial" FontWeight="Normal" Margin="5,0,0,0"/>
                </StackPanel>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>

The custom DataSourceProvider returns the List with 1200 objects:

protected override void BeginQuery()
    {
        System.Threading.ThreadPool.QueueUserWorkItem(RunQuery, null);
    }

    private void RunQuery(object state)
    {
        base.BeginQuery();

        try
        {
            //TODO - do something with the NodeList
            c_pData = c_thisXmlParser.NodeList;

            OnQueryFinished(c_pData, null, null, c_pData);
        }
        catch
        {
            OnQueryFinished(null, null, null, null);
        }
    }

The XmlNode is defined as:

 public class XmlNode
{
    public string Tag { get; set; }
    public string Type { get; set; }
    public string InnerText { get; set; }
    public int FileNumber { get; set; }
    public int NodeDepth { get; set; }
    public int IndexNumber { get; set; }
}

This is the first element in the list :

and the resulting list is shown as this in the window :

The above list should contain a list of Tag elements, and I cannot get a proper understanding of why the Path parameter does not collect the proper elements of the List, and rather provides a list of the first list-elements tag-name.

Answer 1

What you normally bind to ItemsSource is a property that contains some collection of elements. You have bound property Tag that is a string and a string happens to be a collection of characters. That is why each list item contains single character of the foodlist , and WPF is perfectly happy to interpret this binding as FirstOrDefault . What is wrong with your binding is the Path which should be empty. And then in your label where it is empty it should be Tag .

<ListBox Grid.Row="1" ItemsSource="{Binding, Source={ StaticResource txtProvider}}"
             DockPanel.Dock="Bottom">
        <ListBox.ItemTemplate>
            <DataTemplate>
                <StackPanel Orientation="Horizontal">
                    <Label Content="{Binding Path=Tag}" FontFamily="Arial" FontWeight="Normal" Margin="5,0,0,0"/>
                </StackPanel>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>