Entity Framework Create and Update in List - asp.net-mvc

Question

I have an entity that I am updating and the method in the controller has these lines in it;
db.Entry(userdetails).State = EntityState.Modified;
try {
db.SaveChanges();
}
I think this is fine, however the entity has a collection in it and these records needs to be created, not updated. I am therefore getting this error;
"Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. Refresh ObjectStateManager entries."
I have read that this may be because my AppUserInfo objects have an id of 0 because they need to be added.
The class for the outer entity looks like this;
public class User {
public Guid UserId { get; set; }
public string PhoneNumber { get; set; }
public string Email { get; set; }
public List<AppUserInfo> InfoList { get; set; }
}
Now in this situation for example, the phone number could have been modified, and the 'InfoList' collection has new items in that need to be created. Some may need to be updated as well. The 'AppUserInfo' class looks like this;
public class AppUserInfo
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int AppUserInfoId { get; set; }
public string info { get; set; }
}
How do I handle this in EF? Am I allowed to save collections in this way? I do not know how to say that there are modifications and additions and possible deletions in the list to EF. Do I simply just remove the line;
db.Entry(userdetails).State = EntityState.Modified;
Any info on the correct way to do this would be very helpful.
Thanks,

Answer 1

db.Entry(userdetails).State = EntityState.Modified;
This line of code is used for editing your objects, if you have no trouble creating your User then all you need is another controller to handle AppUserInfo
Lets imagine that you have a AppUserInfo controller, and you have a AppUserInfo viewModel somewhere. Then you can somthing like the following to accomplish what you want to do.
Your view model like this:
puclic class AppUserInfoCreateViewModels
{
public Guid UserId { get; set; }
public string Info { get; set; }
}
Then your Controller like this:
public class AppUserInfoController : Controller
{
private readonly IYourDataSource _db;
public AppUserInfoController(IYourDataSource db)
{
_db = db;
}
[HttpGet]
public ActionResult Create(int userId)
{
var model = new AppUserInfoCreateViewModels();
model.UserId = userId;
return View(model);
}
[HttpPost]
public ActionResult Create(AppUserInfoCreateViewModels viewModel)
{
if(ModelState.IsValid)
{
var user = _db.Users.Single(d => d.UserId == viewModel.UserId);
var appUserInfo= new AppUserInfo();
appUserInfo.Info= viewModel.Infor;
user.AppUserInfos.Add(appUserInfo);
_db.Save();
return RedirectToAction("detail", "user", new {id = viewModel.UserId});
}
return View(viewModel);
}
}
I hope this helps, ask any questions you may have