DevExpress: 给ASPxGridView 加右键菜单 ASPxPopupMenu

<%@ Register assembly="DevExpress.Web.v10.1, Version=10.1.5.0, Culture=neutral, PublicKeyToken=41f74a48e1b65e16" namespace="DevExpress.Web.ASPxMenu" tagprefix="dx" %>

<dx:ASPxPopupMenu ID="menuUserGroup" runat="server" ClientIDMode="AutoID"
onitemclick="menuUserGroup_ItemClick" PopupElementID="grvUserGroup">
<Items>
<dx:MenuItem Name="mnuAddRow" Text="增加行">
<Image Url="~/Admin/Images/MenuImg/add.png">
</Image>
</dx:MenuItem>
<dx:MenuItem Name="mnuDeleteRow" Text="删除行">
<Image Url="~/Admin/Images/MenuImg/delete.png">
</Image>
</dx:MenuItem>
<dx:MenuItem Name="mnuEditRow" Text="编辑行">
<Image Url="~/Admin/Images/MenuImg/open.gif">
</Image>
</dx:MenuItem>
</Items>
</dx:ASPxPopupMenu>