WPF Treeview - Binding to a collection with different depths, and styling differently - wpf

Question

Apologies for the long post -- Read a few threads about this, but still find it hard to implement. Basically, I have a collection of objects, defined as:
public class LibData
{
public string Name { get; set; }
ObservableCollection<LibObject> _list;
public ObservableCollection<LibObject> List { get { return _list; } }
public LibData(string name, LibDataType type)
{
this.Name = name;
_list = new ObservableCollection<LibObject>();
}
}
and the object:
public class LibObject
{
public string Name { get; set; }
public LibObject(string name)
{
this.Name = name;
}
}
My main problem is in the XAML, and styling this TreeView. I need to have a specific style for a "root" item, and a specific style for a "leaf". Thing is, that one item in the bound list is "Root->Leaf", and another is "Root->Child->Leaf".
I tried this:
<TreeView x:Name="myTree" ItemsSource="{x:Static local:myDataList}">
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Path=List}" >
<Grid>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Path=Name}" />
<CheckBox IsChecked="True" Content="HeaderCheckbox"/>
</StackPanel>
</Grid>
<HierarchicalDataTemplate.ItemTemplate >
<DataTemplate>
<Grid>
<StackPanel Orientation="Horizontal">
<CheckBox IsChecked="True" Content="LeafCheckbox" />
<TextBlock Text="{Binding Path=Name}"/>
</StackPanel>
</Grid>
</DataTemplate>
</HierarchicalDataTemplate.ItemTemplate>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
This obviously works fine for the "Root->Leaf" item, but not for the "Root-Child-Leaf".
The XAML implementation seems to be more of a "hard coded" solution, where I know that the item layout is always "Root->Leaf" - how do I make this dynamic?
Again, I have seen solutions to different levels (including using converters), but the problem i'm having is that I need specific styles to root and leaf and nothing for levels in between.
I'm wondering if I'm looking at this completely wrong ...

Answer 1

Easy way to do this. Pull the DataTemplates out of the TreeView and put them in the resources section. Specify the DataType property for each DataTemplate, but do not include a key. The ItemTemplateSelector (a property of type DataTemplateSelector) on the TreeView will do the magic of using whichever DataTemplate suits the correct item type.
Create a HierarchicalDataTemplate for types Root and Child, and a DataTemplate for type Leaf.
Something like this:
<Window.Resources>
<ResourceDictionary>
<DataTemplate DataType="{x:Type local:Leaf}">
<Grid>
<StackPanel Orientation="Horizontal">
<CheckBox IsChecked="True" Content="LeafCheckbox" />
<TextBlock Text="{Binding Path=SomeValue}"/>
</StackPanel>
</Grid>
</DataTemplate>
<HierarchicalDataTemplate DataType="{x:Type local:Child}"
ItemsSource="{Binding Children}">
<StackPanel Orientation="Horizontal">
<TextBlock Text="Child " />
<TextBlock Text="{Binding Path=SomeValue}" />
</StackPanel>
</HierarchicalDataTemplate>
<HierarchicalDataTemplate DataType="{x:Type local:Root}"
ItemsSource="{Binding Children}">
<Grid>
<StackPanel Orientation="Horizontal">
<TextBlock Text="Root " />
<TextBlock Text="{Binding Path=SomeValue}" />
</StackPanel>
</Grid>
</HierarchicalDataTemplate>
</ResourceDictionary>
</Window.Resources>
<Grid>
<TreeView x:Name="myTree" ItemsSource="{Binding}" />
</Grid>