dbcontext not saving nor catching exeption - asp.net-mvc

Question

I am using a dbContextwhich is described as the following
public class DbContext: System.Data.Entity.DbContext
{
public DbSet<UserAccount> UserAccounts { get; set; }
public DbSet<Sesison> Sessions { get; set; }
}
And in my login action for some reason after checking with the database that the user is correct i am not able to use another entity of the context to save into the database, whats happens is that i won't get the data saved into the database and it will actually stop executing code after the dc.SaveChanges() but i dont get an exeption on my catch, so what my browser is expiriencing is a 500 internal server error.
public ActionResult Login(LoginViewModel model)
{
using (DbContext dc = new DbContext())
{
var v = dc.UserAccounts.SingleOrDefault(a => a.UserName == model.UserName);
if (v != null)
{
if (GetSHA1(model.Password) == v.Password)
{
Guid sessionGuid =Guid.NewGuid();
var session = dc.Sessions.Add(new Sesison() { SessionID = sessionGuid,StartDateTime=DateTime.UtcNow,UserID = v.UserID,ExpireDateTime=DateTime.UtcNow.AddHours(4)});
System.Web.HttpContext.Current.Session["IsLogin"] = true;
System.Web.HttpContext.Current.Session["Session"] = sessionGuid;
try
{
dc.SaveChanges();
}
catch (System.Data.Entity.Validation.DbEntityValidationException dbEx)
{
Exception raise = dbEx;
foreach (var validationErrors in dbEx.EntityValidationErrors)
{
foreach (var validationError in validationErrors.ValidationErrors)
{
string message = string.Format("{0}:{1}",
validationErrors.Entry.Entity.ToString(),
validationError.ErrorMessage);
// raise a new exception nesting
// the current instance as InnerException
raise = new InvalidOperationException(message, raise);
}
}
throw raise;
}
return Json(new
{
Item1 = "true"
});
}
else
{
return Json(new
{
Item1 = "false",
Item2 = "The username or password you entered is incorrect. Please try again."
});
}
}
else
{
return Json(new
{
Item1 ="false",
Item2 = "The username or password you entered is incorrect. Please try again."
});
}
}
return null;
}

Answer 1

The call to SaveChanges is throwing an exception of a type other than DbEntityValidationException
A quick look at the DbContext SaveChanges call shows that it might throw the following types of exceptions. If you don't want to handle each then you probably want to add a generic Exception handling to find the problem.
// Exceptions:
// T:System.Data.Entity.Infrastructure.DbUpdateException:
// An error occurred sending updates to the database.
//
// T:System.Data.Entity.Infrastructure.DbUpdateConcurrencyException:
// A database command did not affect the expected number of rows. This usually indicates
// an optimistic concurrency violation; that is, a row has been changed in the database
// since it was queried.
//
// T:System.Data.Entity.Validation.DbEntityValidationException:
// The save was aborted because validation of entity property values failed.
//
// T:System.NotSupportedException:
// An attempt was made to use unsupported behavior such as executing multiple asynchronous
// commands concurrently on the same context instance.
//
// T:System.ObjectDisposedException:
// The context or connection have been disposed.
//
// T:System.InvalidOperationException:
// Some error occurred attempting to process entities in the context either before
// or after sending commands to the database.