sharepoint2010 当人员控件显示为中文姓名时 如何获得此人的登录名--SPFieldUserValue用法

    SPSecurity.RunWithElevatedPrivileges(delegate()        //虚拟管理员，否则其他用户访问没有权限                   {                       #region                       using (SPSite site = new SPSite("http://xxxxx.com"))                       {                           using (SPWeb web = site.OpenWeb())                           {                                                             SPList myList = web.Lists["listName"];                               SPQuery myquery = new SPQuery();                                                          SPListItemCollection myItems = myList.Items;                               //获得list 所有item                               DataTable myItem_DT = myItems.GetDataTable();                               myItem_DT.Columns.Add("Hierarchy", Type.GetType("System.String"));                               myItem_DT.Columns.Add("ItemId", Type.GetType("System.Guid"));                               //myItem_DT.Columns.Add("ReportTo", Type.GetType("System.String"));                               labCount.Text = myItem_DT.TableName;                               DataRow[] myItemTempRows;                               string myItemTempUrl = "";                               //给所有item 增加层级结构和itemGUId                               foreach (SPListItem sItem in myItems)                               {                                   //i++;                                   //获得层级结构                                   //Console.WriteLine(sItem.Title);                                   myItemTempRows = myItem_DT.Select("ID='" + sItem.ID.ToString() + "'");                                   myItemTempUrl = sItem.Url.ToString();                                   myItemTempUrl = myItemTempUrl.Substring(myItemTempUrl.IndexOf('/', 2) + 1);                                   myItemTempUrl = myItemTempUrl.Substring(0, myItemTempUrl.LastIndexOf('/'));                                   //TempUrl = TempUrl.Substring();                                   myItemTempRows[0]["Hierarchy"] = myItemTempUrl;                                   myItemTempRows[0]["ItemId"] = sItem.UniqueId;                                                                                                  SPFieldUser field = sItem.Fields["直线经理"] as SPFieldUser;                                                                    if (field != null && sItem["直线经理"] != null)                                   {                                       string myarry = sItem["直线经理"].ToString();                                       SPFieldUserValue GetUser = new SPFieldUserValue(web, sItem["直线经理"].ToString());                                       string ReportTo = GetUser.User.LoginName;                                       myItemTempRows[0]["ReportTo"] = ReportTo;                                                                        }                               }                           }                                                  }                       #endregion                   });