Hello Lala,

Thank you for the code-snippet and the thread reference you have provided.

When the DataItem class (in our case MyClass) contains a child collection, this collection will be displayed as another child layout in the XamDataGrid by default. Since we would like to visualize the items of this collection within a XamComboEditor (instead of in another layout), we can manually disable the visibility of the corresponding field for the collection (the Cities field) and create a new ComboBoxField that is bound the the underlying Cities collection of every MyClass instance.

XAML:

<igDP:Field Name="Name" />

<!-- Displays with additional layout by default -->
<igDP:Field Name="Cities" Visibility="Collapsed" />
<igDP:ComboBoxField Label="Cities Combo" BindingType="Unbound">
  <igDP:ComboBoxField.Settings>
    <igDP:FieldSettings EditorType="{x:Type igEditors:XamComboEditor}">
      <igDP:FieldSettings.EditorStyle>
        <Style TargetType="{x:Type igEditors:XamComboEditor}">
          <Setter Property="ItemsSource" Value="{Binding DataItem.Cities}"/>
        </Style>
      </igDP:FieldSettings.EditorStyle>
    </igDP:FieldSettings>
  </igDP:ComboBoxField.Settings>
</igDP:ComboBoxField>

I have attached a sample application that demonstrates the approach from above.

If you have any questions, please let me know.