数据读取器与指定的不兼容

Question

我使用Code first方法在MVC 4中插入数据，但是，我需要上传文件并使用存储过程保存它的名称，  问题是，数据已成功保存在数据库中，但每次屏幕都显示此错误

控制器方法代码是：

[HttpPost]
    public ActionResult myFile(HttpPostedFileBase file, String fileName )
    {

        if (file.ContentLength > 0) 
           {

               fileName = Path.GetFileName(file.FileName);
               string ext = Path.GetExtension(fileName).ToLower();


            if (ext == ".jpg" || ext == ".jpeg" || ext == ".png" || ext == ".gif")
            {
                if (file.ContentLength > 0.2 * 1024 * 1024)
                { 
                    ViewBag.uploadFailMessage = "Invalid File Size, It must be less than 1 MB";
                }
                else
                {
                    var path = Path.Combine(Server.MapPath("~/uploads"),fileName);
                    file.SaveAs(path);

                          // Saving in DB
                            DBClass db = new DBClass();
                            //var postfrm = db.myFile.Add(upload);
                            //var postForm = db.myFile.Add(filee);         
                    var postForm = (myFile)db.Database.SqlQuery<myFile>("uploadSP @fileName",
                            new SqlParameter("fileName",fileName) 
                             ).FirstOrDefault();  
                          // /Saving in DB
                    ViewBag.uploadSuccessMessage = "File uploaded Succesfully"; 
                }  
            }
            else { ViewBag.uploadFailMessage = "Invalid File"; } 
          }


        return View(); 

    }

型号代码：

namespace MyBook.Models {
public class myFile
{
    [Key]
    public Int64 fileId { get; set; }
    public String fileName { get; set; }
}}