也可以用代码控制的,设置子表的DataColChanged事件:
If e.DataCol.Name = "关联列" AndAlso e.DataRow.IsNull("关联列") = False Then
Dim pr As DataRow = e.DataRow.GetParentRow("父表")
if pr Is Nothing Then
e.Datarow("关联列") = e.OldValue End if
End If