Hey Jenny,

I tried with the post you mentioned. But it is not working. The ComboBox is show empty still. I changed my CellEditor resource as,

 
        <xceed:CellEditor x:Key="SourceFieldEditStyle">
            <xceed:CellEditor.EditTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal" HorizontalAlignment="Stretch" AllowDrop="True">
                        <ComboBox ItemsSource="{Binding dataMapFields}" SelectedValue="{xceed:CellEditorBinding}"  DisplayMemberPath="field_name" SelectedValuePath="field_name" HorizontalAlignment="Stretch"/>
                </StackPanel>
                </DataTemplate>
            </xceed:CellEditor.EditTemplate>
        </xceed:CellEditor>

Thanks