使用外键

如何解决使用外键

我在使用不带Enity Framework的sql查询时从登录用户获取身份主键时遇到问题。 因此，当我从数据库UserDataController中输入用户的登录名和密码时，将UserEmail（登录）复制到WorkSpaceController，并将其放在useremail数据中的公共ActionResult UploadFile（字符串useremail）中。因此，我可以在WorkSpaceController的查询中使用它来获取此电子邮件的ID。但是问题是我无法使用作为插入查询的参数获得的UserID。看下面的代码

UserDataController：

public class UserDataController : Controller
{
    string constr = ConfigurationManager.ConnectionStrings["SQLServer"].ConnectionString;
    // GET: UserData
    [HttpGet]
    public ActionResult Login()
    {
        return View();
    }
}
    [HttpPost]
    public ActionResult Login(UserDataClass log) //Авторизация
    {
        SqlConnection con = new SqlConnection();
        con.ConnectionString = "Data Source=DESKTOP-LRLFA5K\\SQLEXPRESS;Initial Catalog=FileCloud;Integrated Security=True;MultipleActiveResultSets=True";
        SqlDataReader dr;
        con.Open();
        SqlCommand com = new SqlCommand("select * from UserData where UserEmail ='" + log.UserEmail + "' and UserPassword ='" + log.UserPassword + "'",con);
        dr = com.ExecuteReader();
        if (dr.Read())
        {
            Session["useremail"] = log.UserEmail.ToString();
            return RedirectToAction("UploadFile","WorkSpace",new { useremail = log.UserEmail.ToString()});
        }
        else
        {
            ViewData["Message"] = "Неправильное имя пользователя или пароль";
        }
        con.Close();
        return View();
    }
}

WorkSpaceController：

public class WorkSpaceController : Controller
{
    int currentid;
    string constr = ConfigurationManager.ConnectionStrings["SQLServer"].ConnectionString;
    WorkSpaceClass ws = new WorkSpaceClass();
    List<WorkSpaceClass> _ws = new List<WorkSpaceClass>();
    // GET: WorkSpace
    public ActionResult Add()
    {
        return View();
    }
    public ActionResult UploadFile(string useremail)
    {
        UserDataClass info = new UserDataClass();
        info.UserEmail = useremail;
        SqlConnection sqlcon = new SqlConnection(constr);
        string comman = "select UserID from UserData where UserEmail = '" + info.UserEmail + "'"; //??? Вероятно,Email пуст...
        using (SqlCommand sqlcom = new SqlCommand(comman,sqlcon))
        {
            sqlcon.Open();
            currentid = Convert.ToInt32(sqlcom.ExecuteScalar());
        }
        //ws.UserID = id; //UserID не читается
        ViewBag.UserID = currentid;
        sqlcon.Close();
        return View();
    }
    [HttpPost]
    public ActionResult UploadFile(HttpPostedFileBase doc,string useremail) //Загружаем текстовый файл в БД
    {
        ViewBag.UserEmail = useremail;
        if (doc != null)
        {
            ws.FileName = Path.GetFileName(doc.FileName);
            ws.FileData = new byte[doc.ContentLength];
            doc.InputStream.Read(ws.FileData,doc.ContentLength);
            ws.FileExtension = Path.GetExtension(ws.FileName);
            DateTime FileDate = DateTime.Now;

            SqlConnection sqlcon = new SqlConnection(constr);

            ws.FileDate = FileDate.ToString("dd/MM/yyyy");
            if (ws.FileExtension == ".doc" || ws.FileExtension == ".docx" || ws.FileExtension == ".txt" || ws.FileExtension == ".pdf")
            {
                string FilePath = Path.Combine(Server.MapPath("~/FileData"),ws.FileName); //Указываем дирректорию хранения файла
                doc.SaveAs(FilePath); 
                string command = "insert into FileData(FileName,FileData,FileExtension,FileDate,UserID) values(@FileName,@FileData,@FileExtension,@FileDate,@UserID)";
                sqlcon.Open();
                SqlCommand sqlcom = new SqlCommand(command,sqlcon);
                sqlcom.Parameters.Add("@FileName",SqlDbType.VarChar).Value = ws.FileName;
                sqlcom.Parameters.Add("@FileData",SqlDbType.VarBinary).Value = ws.FileData;
                sqlcom.Parameters.Add("@FileExtension",SqlDbType.VarChar).Value = ws.FileExtension;
                sqlcom.Parameters.Add("@FileDate",SqlDbType.VarChar).Value = ws.FileDate;
                sqlcom.Parameters.Add("@UserID",SqlDbType.Int).Value = currentid; //AN ERROR IS HERE
                sqlcom.ExecuteNonQuery(); //BUT THIS ROW IS DISPLAY ON ERROR LOG AND COLORED AS RED
                sqlcon.Close();
            }
        }
        return View(ws);
    }

WorkSpaceClass：

public class WorkSpaceClass
{
    public string FileName { get; set; }
    public byte[] FileData { get; set; }
    public string FileExtension { get; set; }
    public string FileDate { get; set; }
    public int UserID { get; set; }
}

WorkSpaceClass：

public class UserDataClass
{
    public int UserID { get; set; }
    [Display(Name = "Имя")]
    [Required(ErrorMessage = "Введите имя пользователя")]
    public string UserName { get; set; }
    [Display(Name = "Email")]
    [Required(ErrorMessage = "Введите Email")]
    public string UserEmail { get; set; }
    [Display(Name = "Пароль")]
    [Required(ErrorMessage = "Введите пароль")]
    public string UserPassword { get; set; }
    [Display(Name = "Подтверждение пароля")]
    [Required(ErrorMessage = "Подтвердите пароль")]
    public string ConfirmPassword { get; set; }
    [Display(Name = "Выберите изображение")]
    public byte[] AvatarData { get; set; }
}

This is columns types from SQL Server

因此，如果我在“ currentid”位置文件中将任何类似1或2的int数（sqlcom.Parameters.Add（“ @ UserID”，SqlDbType.Int）.Value = currentid;）放在一行中，则会上传到具有此ID的当前用户。 我认为问题是行“ currentid = Convert.ToInt32（sqlcom.ExecuteScalar（））;”但我无法想象如何解决它。 希望您能帮到我，我已经坚持了两天。我是MVC ASP.NET的新手，因此此错误通常是您的... 使用ViewBag，我测试了我获得的值，它是“ useremail”上当前电子邮件中正确的id int值。

解决方法

我尚未测试您的代码，但错误说明了自己。这段代码正在为表barman@4b412c1875cd:~$ date Sat Aug 8 02:47:13 UTC 2020 barman@4b412c1875cd:~$ barman recover --target-time "2020-08-08 02:31:00+00:00" postgres-source-db 20200801T030001 /var/log/barman/TESTRESTOREFORTEST Starting local restore for server postgres-source-db using backup 20200801T030001 Destination directory: /var/log/barman/TESTRESTOREFORTEST Doing PITR. Recovery target time: '2020-08-08 02:31:00+00:00' Copying the base backup. Copying required WAL segments. Generating recovery configuration Identify dangerous settings in destination directory. Recovery completed (start time: 2020-08-08 02:50:46.538480,elapsed time: 1 second) Your PostgreSQL server has been successfully prepared for recovery! barman@4b412c1875cd:~$ 中不存在的FileData插入UserID；原因就是UserData迷失的价值。

到达currentid时，您是在新请求中，因此UploadFile(HttpPostedFileBase doc,string useremail)和ViewData将无济于事，ViewBag迷路了。在此控制器操作方法中，您需要currentid，TempData或新参数来检索Session的值。如果您之前已将值保存在UserId中，请尝试以下操作：

TempData