WPF Combobox behavior weird

Question

Hi guys, I have 2 comboboxes which we will call cbo1 and cbo2. Now, there is a relationship between cbo1 and cbo2. when i select an item at cbo1, the cbo2 ItemsSource is updated (since it is bound to the SelectedItem) anyway, below is the sample XAML code for it.

<ComboBox x:Name="cbo1" Grid.Row="0" Grid.Column="1" Margin="5" SelectedItem="{Binding Path=Brand}"></ComboBox>
<ComboBox x:Name="cbo2" Grid.Row="1" Grid.Column="1" Margin="5" SelectedItem="{Binding Path=Model}" ItemsSource="{Binding ElementName=cbo1, Path=SelectedItem.Models}" DisplayMemberPath="Name"></ComboBox>

the objects used are Brand and Model. Brand has a property named Models which contain a collection of Model objects ( typeof IList ). So basically, a one-many relationship between the 2 classes.

By the way, those 2 classes are used in NHibernate. Now, when I run the app, cbo1 which contains a collection of Brand objects is loaded with the items first. When I select a Brand item, the cbo2 with the Model collection is populated. As you have noticed, both Comboboxes have SelectedItem property bound to the current object properties Brand and Model specifically. When I select a Model on the cbo2, it does not reflect to the current object's Model property. Anything i missed?

Answer 1

typo: the first combo is called cbo1, but the second combo is binding to cbxBrand; but since you say the Models do appear, I'm guessing this is OK in your actual source code, and you renamed it for the Question here?

Anyway, your code completely worked for me, I put a breakpoint on the setter of the Model property and it hit it no probs, so the only thing I can possibly guess at is the Window's DataContext maybe incorrect? Can you post your code-behind (or ViewModel) ?