Question

Following is the code I wrote for generating treeview hierarchy,

    For Each k As KeyValuePair(Of String, GenreSet) In GenreSetDictionary
        Dim t As New TreeNodeSet
        t.Genre = True
        t.Imagepath = k.Value.IconPath
        t.Namee = k.Key
        Dim pnode As New TreeViewItem
        pnode.DataContext = t
        pnode.Visibility = True
        For Each z As DatabaseDearDataSet.DiskListRow In adpt.GetDataByGenre(t.Namee)
            Dim tt As New TreeNodeSet
            tt.Genre = False
            tt.Imagepath = IconDictionary(z.DiskIcon).IconPath
            tt.Namee = z.DiskName
            Dim cnode As New TreeViewItem
            cnode.DataContext = tt
            pnode.Items.Add(cnode)
        Next
        DisksTreeView1.Items.Add(pnode)
    Next

Following is the code I have used in XAML:

<TreeView Height="211" HorizontalAlignment="Left" Margin="19,15,0,0" Name="TreeView1" VerticalAlignment="Top" Width="346">
    <TreeView.ItemTemplate>
        <DataTemplate>
            <StackPanel Orientation="Horizontal">
                <Image Source="{Binding ImagePath}" Width="32" Height="32"/>
                <TextBlock Text="{Binding Namee}" VerticalAlignment="Center" HorizontalAlignment="Center" />
            </StackPanel>
        </DataTemplate>
    </TreeView.ItemTemplate>
</TreeView>

However, I was not able to get that work, could you please tell me where my XAML went wrong please.

Answer 1

I see few minor mismatches here: the name of the TreeView control (TreeView1 or DisksTreeView1) and the ImagePath property (or Imagepath, c# is sensible to the register of variables).

But the main reason of the incorrect behavior is that the ItemTemplate property is applied to the ItemsSource property, not to the Items property.

Here are two possible ways to correct the code:

1) Fixeing of the data class, item template and binding to the ItemsSource

• Create the myObservableCollection private field of the type ObservableCollection(Of TreeNodeSet).
• Add to the constructor the line DisksTreeView1.ItemsSource = myObservableCollection
• Change the line DisksTreeView1.Items.Add(pnode) to the line myObservableCollection.Add(t).
• Add the Disks property to the TreeNodeSet class (the type is ObservableCollection too)
• In the xaml replace the line with DataTemplate to the line <HierarchicalDataTemplate ItemsSource="{Binding Disks}"
• Change the line pnode.Items.Add(cnode) to the line t.Disks.Add(tt).

2) Using the HeaderTemplate property instead of the ItemTemplate property.

At first, move the DataTemplate to resources and add some key. Then add a similar code near each TreeViewItem in the code-behind:

    Dim pnode As New TreeViewItem
    pnode.DataContext = t
    pnode.Header = t
    pnode.HeaderTemplate = Resources("someKey")