没有为此对象定义无参数构造函数。 当Iam尝试更新图片时

Question

net-Mvc5我正在更新已经保存在数据库中的Imagepath，但出现此错误

没有为此对象定义无参数构造函数。

//  Parameter less Constructor:: 
public EditclassWorkController()
{
}

// Code For Index Controller:
public ActionResult Index(HttpPostedFile file)
{

   return View();
}


//  Code for update ImagePath :   
[HttpPost]
public ActionResult Edit(tbl_classWork vehi,HttpPostedFile file)
{
   SchoolERP db = new SchoolERP();
   tbl_classWork imgToSave = 
  (
   from imga in db.tbl_classWork
   where imga.Classwork_id == vehi.Classwork_id
   select imga
  ).First();
   if (ModelState.IsValid)
   {
       if (vehi != null)
       {
         imgToSave.class_file = file.ContentType;
         var binaryReader = new BinaryReader(file.InputStream);
         imgToSave.class_file = binaryReader.ReadBytes(file.ContentLength).ToString();
          binaryReader.Close();
       }
       TryUpdateModel(imgToSave);
       db.SaveChanges();
       return RedirectToAction("Index");
   }
     //No path Found return Else part:
       else
       {
         return View(vehi);
       }
}