I have spent nearly seven hours to figure this out and couldn't come up with a solution. So here am I, sharing this problem with you.
Please note that the following example is a simplification and subset of my original project. I tried to simplify it as much as possible for you.
To start, I have two business models:
The following EDMX diagram is as follows:
I am using MVC 4 and I have a simple page where you can enter home and away team names respectively and a save button to save these teams and the match:
CSHTML
@model TestEF.Data.Match
@{
Layout = null;
}
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width" />
<title>NewMatch</title>
</head>
<body>
<div>
Status: @ViewBag.Status
</div>
<div id="NewMatchFormContainer">
@using (Ajax.BeginForm(new AjaxOptions() { Url = "/Match/NewMatch", UpdateTargetId = "NewMatchFormContainer" }))
{
@Html.ValidationSummary(false)
@Html.TextBox("HomeTeamName", "", new { Name = "HomeTeam.TeamName" });
@Html.TextBox("AwayTeamName", "", new { Name = "AwayTeam.TeamName" });
<input type="submit" value="Save" />
}
</div>
</body>
</html>
Controller
public class MatchController : Controller
{
TestEFEntities _dbContext = new TestEFEntities();
public ActionResult Index()
{
return View();
}
public ActionResult NewMatch()
{
return View();
}
[HttpPost]
public ActionResult NewMatch(Match matchData)
{
try
{
if (ModelState.IsValid)
{
using (TransactionScope ts = new TransactionScope())
{
string homeTeamName = matchData.HomeTeam.TeamName;
Team existingHomeTeam = _dbContext.Teams.SingleOrDefault(i => i.TeamName == homeTeamName);
Team homeTeam = existingHomeTeam ?? matchData.HomeTeam;
homeTeam.UpdatedDate = DateTime.Now;
if (existingHomeTeam == null)
{
_dbContext.AddToTeams(homeTeam);
}
else
{
_dbContext.ObjectStateManager.ChangeObjectState(homeTeam, System.Data.EntityState.Modified);
}
string awayTeamName = matchData.AwayTeam.TeamName;
Team existingAwayTeam = _dbContext.Teams.SingleOrDefault(i => i.TeamName == awayTeamName);
Team awayTeam = existingAwayTeam ?? matchData.AwayTeam;
awayTeam.UpdatedDate = DateTime.Now;
if (existingAwayTeam == null)
{
_dbContext.AddToTeams(awayTeam);
}
else
{
_dbContext.ObjectStateManager.ChangeObjectState(awayTeam, System.Data.EntityState.Modified);
}
matchData.HomeTeam = homeTeam;
matchData.AwayTeam = awayTeam;
_dbContext.AddToMatches(matchData);
_dbContext.SaveChanges();
ts.Complete();
}
ViewBag.Status = "Success";
return PartialView(matchData);
}
else
{
ViewBag.Status = "Invalid input.";
return PartialView(matchData);
}
}
catch (Exception ex)
{
ViewBag.Status = "Error: " + (ex.InnerException != null ? ex.InnerException.Message : ex.Message);
return PartialView(matchData);
}
}
}
As you can see inside the controller, the entered team name is compared to those in the database. If one exists, it is to be updated; else inserted. There are no problems with inserts but when an existing team name is entered inside a textbox, I get the following error message:
Cannot insert the value NULL into column 'UpdatedDate', table 'TestEF.dbo.Teams'; column does not allow nulls. INSERT fails. The statement has been terminated.
I get this error even though inside the controller, I explicitly set the UpdateDate for records that need to be updated and set its state to Modified. However the error message says as if UpdateDate field was not set. I debugged and made sure the fields are updated correctly but in SQL Profiler UpdateDate is not set. I am very confused.
I can share the full source code if needed.
UPDATE I suspect it has something to do with Attach/Detach but I am not sure.
UPDATE 2 I have simplified the code to see whether it works and it does. Then why does the original code not work?
Team homeTeam = new Team() { TeamId = 1 };
Team awayTeam = new Team() { TeamId = 2 };
_dbContext.Teams.Attach(homeTeam);
homeTeam.UpdatedDate = DateTime.Now;
_dbContext.Teams.Attach(awayTeam);
awayTeam.UpdatedDate = DateTime.Now;
Match newMatch = new Match()
{
HomeTeam = homeTeam,
AwayTeam = awayTeam,
UpdateDate = DateTime.Now
};
_dbContext.AddToMatches(newMatch);
_dbContext.SaveChanges();
xxx.UpdatedDate = DateTime.Now;AFTER doing the_dbContext.ObjectStateManager.ChangeObjectState...statement inside theelse? So, re-set it if updating? Try that and see if it solves your problem. If it works let me know and I will post answer. – Hughey