ItemContainerStyleSelector导致绑定错误

Question

我有两种对象类型，为简单起见，我将其称为Category和Product。类别可以包含子类别以及产品。产品不包含其他对象 - 它们是树中的叶子。

public class Product
{
    public string Name {get; set;}
}

public class Category
{
    public IEnumerable<object> Children
    {
        //return a mixed set of categories and products
    }

    public bool IsExpanded {get; set;}

    public bool IsHighlighted {get; set;}
}

我想以它们在对象图中出现的确切方式在TreeView中显示它们。 e.g。

Category 1
    Product
    Category 1.1
    Category 1.2
        Product
    Product
Category 2
    Category 2.1
        Category 2.1.1
    Product

等等。我的XAML是

<UserControl xmlns:.....>
<UserControl.Resources>
    <Style x:Key="CategoryStyle" TargetType="TreeViewItem">
        <Setter Property="IsExpanded" Value="{Binding IsExpanded ,Mode=TwoWay}"/>
        <Style.Triggers>
            <DataTrigger Binding="{Binding IsHighlighted}" Value="True">
                <Setter Property="FontWeight" Value="Bold"/>
            </DataTrigger>
        </Style.Triggers>
    </Style>
    <local:TreeItemStyleSelector x:Key="TreeItemStyleSelector" />
</UserControl.Resources>

<Grid>
    <TreeView ItemContainerStyleSelector="{StaticResource TreeItemStyleSelector}">
    <!-- ItemContainerStyleSelector causes binding errors-->
        <TreeView.Resources>
            <!-- template for products -->
            <DataTemplate DataType="{x:Type local:Product}">
                <Button Content="{Binding Name}" Style="{StaticResource ButtonStyle}"/>
            </DataTemplate>
            <!-- template for categories -->
            <HierarchicalDataTemplate DataType="{x:Type local:Category}" ItemsSource="{Binding Children}">
                <StackPanel Orientation="Horizontal">
                    <!-- template omitted here -->
                </StackPanel>
            </HierarchicalDataTemplate>
        </TreeView.Resources>
    </TreeView>
</Grid>
</UserControl>

树呈现正确，但我在输出窗口中收到很多绑定错误，称Product没有名为Children，IsExpanded和IsHighlighted的属性。似乎WPF尝试在产品上应用HierarchicalDataTemplate 有意思，但是当我删除ItemContainerStyleSelector时，没有引发任何绑定错误。选择器代码非常简单

public class TreeItemStyleSelector : StyleSelector
{
    public override System.Windows.Style SelectStyle(object item, DependencyObject container)
    {
        if(item is Category)
        {
            return (System.Windows.Style)((FrameworkElement)container).FindResource("CategoryStyle");
        }
        return null;
    }
}

如何防止引发错误？
任何帮助将不胜感激。