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>