WPF将编号绑定到不同的datacolumn中

<dg:DataGridComboBoxColumn Header="Priority" SelectedItemBinding="{Binding priority}" Width="SizeToCells" MinWidth="60" CanUserSort="True">
   <dg:DataGridComboBoxColumn.ItemsSource>
      <col:ArrayList>
         <s:String>Low</s:String>
         <s:String>Medium</s:String>
         <s:String>High</s:String>
       </col:ArrayList>
   </dg:DataGridComboBoxColumn.ItemsSource>
</dg:DataGridComboBoxColumn>