title: WPF Datagrid ComboBox DataBinding
body: <p>Can anyone tell me why this works;</p>
  
  <pre><code>&lt;DataGridTemplateColumn Header="Supplier"&gt;
    &lt;DataGridTemplateColumn.CellTemplate&gt;
        &lt;DataTemplate&gt;
            &lt;ComboBox DisplayMemberPath="SupplierName" SelectedValuePath="SupplierID" 
                      SelectedValue="{Binding SupplierID}"
                      ItemsSource="{Binding Path=DataContext.Suppliers, RelativeSource={RelativeSource AncestorType={x:Type Window}}}" /&gt;
        &lt;/DataTemplate&gt;
    &lt;/DataGridTemplateColumn.CellTemplate&gt;
  </code></pre>
  
  <p>but this doesn't;</p>
  
  <pre><code>&lt;DataGridComboBoxColumn Header="Combo" DisplayMemberPath="SupplierName" SelectedValuePath="SupplierID" 
    SelectedValueBinding="{Binding SupplierID}"
    ItemsSource="{Binding Path=DataContext.Suppliers, RelativeSource={RelativeSource AncestorType={x:Type Window}}}" /&gt;
  </code></pre>
  
  <p>Second snippet does not show the list of SupplierName on edit...</p>