public async Task <IActionResult> Index() { IEnumerable <Column2ModelEntity> list = await columnService.GetAllColumn2ModelListAsync(); var data = list.ToList(); List <Column2ModelEntity> entitys = data.FindAll(t => t.C_PARENTID == 0); int i = 0; foreach (var item in entitys) { if (item.C_CHILDREN > 0) { navHtml.AppendFormat("<li{0}>", i > 0 ? " class=\"closed\"" : ""); navHtml.AppendFormat("<span class=\"folder\">{0}</span>", item.C_NAME); ResolveSubTree(data, item.C_ID); } else { navHtml.Append("<li>"); string link = String.Empty; if (item.C_TYPEID == 10002) { if (item.M_ID > 0) { link = item.M_MANAGEURL + "?cid=" + +item.C_ID; } } navHtml.AppendFormat("<a href=\"{0}\" target=\"myFrameName\"><span class=\"file\">{1}</span></a>", link, item.C_NAME); } navHtml.Append("</li>"); i++; } ViewBag.MenuNav = navHtml.ToString(); return(View()); }