Binding a Silverlight DataGrid’s ComboBox To a Model

I have a DataGrid that is bound to my Employee entity and I needed to be able to select his building from a list of buildings in that same model. There is a path to the Employee’s Building through buildingId, but no path to the full list of buildings so it could the source for the ComboBox.

The simple solution was to have the Buildings in a ViewModel and then reference that as a resource in my XAML.  The ViewModel retrieves the data in it’s constructor and it has a property EntitySet<Building> Buildings;

    <UserControl.Resources>
        <vm:BuildingsModel x:Key="buildingsModel"  />
    </UserControl.Resources>

Then on the CheckBox inside the <DataTemplate> I have its ItemSource use the resource.

<ComboBox Name="cb" ItemsSource="{Binding Source={StaticResource buildingsModel}, Path=Buildings}" 
    SelectedValuePath="id" 
    SelectedValue="{Binding Path=buildingId, Mode=TwoWay}">
    <ComboBox.ItemTemplate>
        <DataTemplate>
            <StackPanel Orientation="Horizontal">
                <TextBlock Text="{Binding name, Mode=OneWay}" MinWidth="140" />
                <TextBlock Text="  " />
                <TextBlock Text="{Binding address, Mode=OneWay}" />
                <TextBlock Text=", " />

                <TextBlock Text="{Binding city, Mode=OneWay}" />
                <TextBlock Text=", " />
                <TextBlock Text="{Binding state, Mode=OneWay}" />
            </StackPanel>
        </DataTemplate>
    </ComboBox.ItemTemplate>
</ComboBox>