在asp.net mvc中而不是UI中发布表单后获取纯HTML

Question

我在发布表单时遇到了一些麻烦，当我使用asp.net mvc发布表单时，我在浏览器中没有预期的UI时收到纯HTML作为响应。我检查了Post方法中的所有内容，对我来说您可以帮助问题出在哪里或发生这种意外行为的可能性。

[HttpGet]
    public ActionResult SchoolBoards()
    {
                POCO_SchoolBoard schoolBoardobj = new POCO_SchoolBoard();
                using (UdijaDBContext DBContext = new UdijaDBContext())
                {
                    List<SchoolBoardInformation> boardinfoList = new List<SchoolBoardInformation>();
                    boardinfoList = DBContext.SchoolBoards.Select(S => new SchoolBoardInformation
                    {
                        BoardId = S.SchoolBoardID,
                        BoardName = S.SchoolBoardName,
                        Count = DBContext.Schools.Where(w => w.SchoolType == S.SchoolBoardID && w.currentAcademicYear == Admin.CurrentAcademicYear).Count(),
                    }).OrderBy(o => o.BoardName).ToList();
                    ViewBag.boardinfoList = boardinfoList;
                }
                return View(schoolBoardobj);
    }

在这里，我得到了正确的用户界面。例如：

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult SchoolBoards(POCO_SchoolBoard schoolBoardObj)
{
        UserInformation Admin = Session["UserInfo"] as UserInformation;
                            using (UdijaDBContext DBContext = new UdijaDBContext())
            {
                if (ModelState.IsValid)
                {
                    //Add new school Board
                    SchoolBoard board = new SchoolBoard();
                    board.SchoolBoardName = schoolBoardObj.BoardName;
                    board.ModifiedBy = Admin.UserId;
                    board.ModifiedOn = DateTime.Now;
                    DBContext.SchoolBoards.Add(board);
                    DBContext.SaveChanges();

                    ModelState.Clear();
                    schoolBoardObj = new POCO_SchoolBoard();
                    return RedirectToAction("SchoolBoards", "Admin");
                }
                else
                {
                    ModelState.AddModelError("", ModelState.GetErrorMessage());
                }
                List<SchoolBoardInformation> boardinfoList = new List<SchoolBoardInformation>();
                boardinfoList = DBContext.SchoolBoards.Select(S => new SchoolBoardInformation
                {
                    BoardId = S.SchoolBoardID,
                    BoardName = S.SchoolBoardName,
                    Count = DBContext.Schools.Where(w => w.SchoolType == S.SchoolBoardID && w.currentAcademicYear == Admin.CurrentAcademicYear).Count(),
                }).OrderBy(o => o.BoardName).ToList();
                ViewBag.boardinfoList = boardinfoList;
            }
            return View(schoolBoardObj);
}

但是这里我在浏览器中得到纯HTML，例如：

这可能是什么原因