CODEWITHSUNDEEP
c#asp.net-mvc-5
Denis Steinman
Denis Steinman

Reputation: 7799

System.Object constant cannot be created in this context

I try to write code that will iterate through my DbSet<staffCompetence> but it doesn't work.

[HttpPost]
public ActionResult Index(StaffWrapper sw, HttpPostedFileBase file)
{
    var st = db.staff.Where(s => s.ID.Equals(sw.Id)).FirstOrDefault();

    if (st != null)
    {
        var cvs = TokenBoxExtension.GetSelectedValues<Guid>("StaffCompetenceTokenBox");
        UpdateCompetenceLinks(st.ID, cvs);
        //Rewrite values...

        db.Entry(st).State = EntityState.Modified;
        db.SaveChanges();
    }

    return View(sw);
}

private void UpdateCompetenceLinks(Guid staffId, Guid[] ids)
{
    var model = db.staffCompetence;

    for (int i = 0; i < ids.Length; ++i)
    {
        var id = ids[i];
        //On line below it crashes
        var scs = model.Where(s => s.competenceID.Equals(id)).ToList(); //ToList() for test

        if (!scs.Any())
        {
        }
    }
}

It crashes in the if condition with exception NotSupported and a message that it can't create System.Object constant in this context. What does it mean? And how to fix it?

P.S. I use Russian located debugger, so I can't post a log. ADDED

Исключение типа "System.NotSupportedException" возникло в EntityFramework.SqlServer.dll, но не было обработано в коде пользователя

Дополнительные сведения: Не удалось создать константу с типом "System.Object". В этом контексте поддерживаются только типы-примитивы и типы перечисления.

In English:

The exception of "System.NotSupportedException" type appears in EntityFramework.SqlServer.dll, but it was not handled by the user code.

Details: The constant creation with "System.Object" type failed. In this context type-premitives and iteration types support only.

P.P.S I translated as I can.

Upvotes: 1

Views: 553

Answers (2)

xqMogvKW
xqMogvKW

Reputation: 628

You codes can be simplified to something like this following:

using (dbPMEntities db = new dbPMEntities())
{
var model = db.staffCompetence;

foreach (Guid id in ids)
{
    **var scs = model.FirstOrDefault(s => s.competenceID.HasValue?s.competenceID.CompareTo(id):null);   //Do double-check to see whether the competenceID is of a real value……and check firstOrDefault()**

    if (scs==null)
    {
        var item = new staffCompetence();
        item.recID = Guid.NewGuid();
        item.competenceID = id;
        model.Add(item);
    }
 }
}

Upvotes: 1

Adnan Umer
Adnan Umer

Reputation: 3689

You can't compare System.Guid directly. Do compare using Guid.CompareTo instead

dbPMEntities db = new dbPMEntities();
var model = db.staffCompetence;

foreach (Guid id in ids)
{
    var scs = model.Where(s => s.competenceID.CompareTo(id) > 0);

    if (!scs.Any())
    {
        var item = new staffCompetence();
        item.recID = Guid.NewGuid();
        item.competenceID = id;
        model.Add(item);
    }
}

Upvotes: 0

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