Entity Framework: An object with the same key already exists in the objectstatemanager
- by NealR
I see that this question has been asked a lot, however I haven't found anything yet that solves the problem I'm having.
Obviously i'm using the Entity Framework to perform an update to a record. Once the updates are complete, however, whenever I try to save I get the following error message:
An object with the same key already exists in the objectstatemanager
At first I was passing in a collection object from the view that contained a copy of the the ZipCodeTerritory model object zipToUpdate. I changed the code by pulling this object out and just sending in the relevant fields instead. However, I'm still getting the same error.
What's also weird is the first time I run this code, it works fine. Any attempt after that I get the error.
Controller
Here is the code from the method calling the edit function
public static string DescriptionOnly(ZipCodeIndex updateZip)
{
if (!string.IsNullOrWhiteSpace(updateZip.newEffectiveDate) || !string.IsNullOrWhiteSpace(updateZip.newEndDate))
{
return "Neither effective or end date can be present if updating Territory Code only; ";
}
_updated = 0;
foreach (var zipCode in updateZip.displayForPaging.Where(x => x.Update))
{
ProcessAllChanges(zipCode, updateZip.newTerritory, updateZip.newStateCode, updateZip.newDescription, updateZip.newChannelCode);
}
_msg += _updated + " record(s) updated; ";
return _msg;
}
And here is the method that actually does the updating.
private static void ProcessAllChanges(ZipCodeTerritory zipToUpdate, string newTerritory, string newStateCode, string newDescription,
string newChannelCode)
{
try
{
if (!string.IsNullOrWhiteSpace(newTerritory)) zipToUpdate.IndDistrnId = newTerritory;
if (!string.IsNullOrWhiteSpace(newStateCode)) zipToUpdate.StateCode = newStateCode;
if (!string.IsNullOrWhiteSpace(newDescription)) zipToUpdate.DrmTerrDesc = newDescription;
if (!string.IsNullOrWhiteSpace(newChannelCode)) zipToUpdate.ChannelCode = newChannelCode;
if (zipToUpdate.EndDate == DateTime.MinValue) zipToUpdate.EndDate = DateTime.MaxValue;
_db.Entry(zipToUpdate).State = EntityState.Modified;
_db.SaveChanges();
_updated++;
}
catch (DbEntityValidationException dbEx)
{
_msg += "Error during update; ";
EventLog.WriteEntry("Monet", "Error during ProcessAllChanges: " + zipToUpdate.ToString() + " |EX| " + dbEx.Message);
}
catch (Exception ex)
{
_msg += "Error during update; ";
EventLog.WriteEntry("Monet", "Error during ProcessAllChanges: " + zipToUpdate.ToString() + " |MESSAGE| " + ex.Message);
}
}
EDIT
The ZipCodeIndex object contains a list of ZipCodeTerritory model objects. These aren't being pulled from a linq query, but instead simply passed back to the controller from the view. Here is the signature of the controller method that starts the process:
[HttpPost]
public ActionResult Update(ZipCodeIndex updateZip, string button)
