Thari Thari - 28 days ago 6
C# Question

How to update a record in database in Entity Framework?

I'm using c# mvc with EF and i'm building a website. When i'm updating a table with new values it gives the following error.


{"Violation of PRIMARY KEY constraint 'PK_Table_1_1'. Cannot insert duplicate key in object 'dbo.User'. The duplicate key value is (shan@gmail.com).\r\nThe statement has been terminated."}


Here is my design of the table.

enter image description here

Here is my controller file

[HttpPost]
public ActionResult Manage(ManageViewModel manageviewmodel)
{
TheFoodyContext db = new TheFoodyContext();
string UserEmail = Session["UserEmail"].ToString();
User user_to_update = db.Users.Find(UserEmail);

if (ModelState.IsValid)
{

try
{
HttpPostedFileBase photo = Request.Files["photo"];

if (photo != null && photo.ContentLength > 0)
{
var path = "";
var fileName = Path.GetFileName(photo.FileName);
var extension = Path.GetExtension(photo.FileName);
var allowedExtensions = new[] {".Jpg", ".png", ".jpg", "jpeg"};
if (allowedExtensions.Contains(extension))
{
string name = Path.GetFileNameWithoutExtension(fileName);
string myfile = name + "_" + UserEmail + extension;
path= Path.Combine(Server.MapPath("~/Img"), myfile);
photo.SaveAs(path);
user_to_update.photo = myfile;

}
else
{
ViewBag.message = "Please choose only Image file";
}


user_to_update.email = UserEmail;
user_to_update.fname = manageviewmodel.FirstName;
user_to_update.lname = manageviewmodel.LastName;
user_to_update.phone = manageviewmodel.Phone;
user_to_update.address = manageviewmodel.Address;
user_to_update.city = manageviewmodel.City;
user_to_update.postcode = Convert.ToDecimal(manageviewmodel.PostCode);
user_to_update.district = manageviewmodel.District;
user_to_update.user_type = manageviewmodel.UserType;
user_to_update.status = manageviewmodel.Status;
user_to_update.photo = path;

db.Users.Add(user_to_update);
db.SaveChanges();

Session["UserEmail"] = UserEmail;
Session["FirstName"] = manageviewmodel.FirstName;
Session["LastName"] = manageviewmodel.LastName;
Session["Address"] = manageviewmodel.Address;
Session["City"] = manageviewmodel.City;
Session["PostCode"] = manageviewmodel.PostCode;
Session["District"] = manageviewmodel.District;
Session["UserType"] = manageviewmodel.UserType;
Session["Status"] = manageviewmodel.Status;
Session["Phone"] = manageviewmodel.Phone;
return RedirectToAction("Manage");
}
}
catch (Exception ex)
{
return View(ex.Message);
}
return View(manageviewmodel);
}

return View(manageviewmodel);

}


Here is my Model file

public class ManageViewModel
{
public string FirstName { get; set; }
public string LastName { get; set; }
public string Email { get; set; }
public string Phone { get; set; }
public string photo { get; set; }
public string Address { get; set; }
public string City { get; set; }
public int PostCode { get; set; }
public string District { get; set; }
public string UserType { get; set; }
public string Status { get; set; }
}

Answer

You don't need to add the user again (it already exists and EF tracks changes), simply call SaveChanges and you are done.
Just remove this line:

db.Users.Add(user_to_update);

and it should work (unless there are more errors).

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