TreeView databinding problems with Silverlight and Caliburn Micro

I have using Silverlight and Caliburn Micro and am having a problem getting child nodes to appear in the tree. The TreeView is contaimed in a grid and here is my XAML excerpt:

<Grid.Resources>
    <sdk:HierarchicalDataTemplate x:Key="AccountTemplate">
        <TextBlock Text="{Binding AccountNumber}" />
    </sdk:HierarchicalDataTemplate>
    <sdk:HierarchicalDataTemplate x:Key="CategoryTemplate"
                                  ItemsSource="{Binding CategoryServices}"
                                  ItemTemplate="{StaticResource AccountTemplate}">
        <TextBlock Text="{Binding Path=CategoryName}" FontWeight="Bold" />
    </sdk:HierarchicalDataTemplate>
</Grid.Resources>

<Controls:TreeView Grid.Row="1" Grid.Column="0" 
    ItemsSource="{Binding FromAddressServices}" 
    ItemTemplate="{StaticResource CategoryTemplate}" x:Name="FromTreeView" />

The classes that are bound are:

public class AccountAtAddress
{
    public string AccountNumber { get; set; }
}

public class ServiceCategory
{
    public string CategoryName { get; set; }
    public ObservableCollection<AccountAtAddress> CategoryServices;
}

The problem that I have i开发者_运维百科s that the first level items show but no children. Does anyone have ideas for how to make this work?

You need to make CategoryServices into a public property. You have it defined as a public field and the databinding mechanism doesn't work with fields.

Try the following instead:

<Grid.Resources>
    <sdk:HierarchicalDataTemplate DataType="AccountAtAddress">
        <TextBlock Text="{Binding AccountNumber}" />
    </sdk:HierarchicalDataTemplate>
    <sdk:HierarchicalDataTemplate DataType="ServiceCategory"
                                  ItemsSource="{Binding CategoryServices}">
        <TextBlock Text="{Binding Path=CategoryName}" FontWeight="Bold" />
    </sdk:HierarchicalDataTemplate>
</Grid.Resources>