Question

Let’s say I create a new Entity and Save it as follows:

UserReport report = new UserReport() {//set the props}
manager.SaveUserReport(report)

Public UserReport SaveUserReport(UserReport report)
{
  using(var context = new ReportDatabase())
  {
    context.UserReports.AdObject(report);
    context.SaveChanges();
  }
  return report;
}

so far so good

I then read back the saved Report

 savedReport = manager.GetUserReports(new int[] {report.Id}).FirstOrDefault();

 Public List<UserReport> GetUserReports(IEnumerable<int> reportIds)
 {
     using (var context = new ReportDatabase())
     {
        var reports = from UserReport in context.UserReports
          where reportIds.Contains(userReport.Id)
          select userReport;
          return visibleReports.ToList();
     }
 }

savedReport is now an attached UserReport

The UserReport object has a collection of Columns attached to it.

I want to replace the set of Columns attached with another set (that already exist in the database).

 savedReport.Columns = newColumnCollection

This fails with the error “The property Columns” on type UserReport_etc’ cannot be set because the collection is already set to an EntityCollection”

I’ve looked at this article: the problem is the same, but I cannot use that solution.

What is the correct way to tackle this?

Answer 1

OK – looks like it’s just a case of setting the non-navigation properties to not be virtual.

That is one hell of a weird situation, given that the behaviour that is modified is of properties that remain as virtual.