Transient parameter

[Vincent]

Hi,

I'm trying the new version of Open Access (Telerik_OpenAccess_ORM_2009_1_311_trial) and I created the SofiaCarRental example. Everything works fine.

Now I'm trying to query some table of our database and I get the following error:

{"PC parameter 0 is transient: Entities.ContactPerson: Entities.ContactPerson"}    Telerik.OpenAccess.OpenAccessException {Telerik.OpenAccess.Exceptions.InvalidOperationException}

The following code works fine:
    var getPersons = from persons in newScope.Extent<ContactPerson>()
                           where persons.Username == person.Username && persons.Password == "secret"
                           select persons;

The following code goes wrong:
    var getPersons = from persons in newScope.Extent<ContactPerson>()
                           where persons.Username == person.Username && persons.Password == person.Password
                           select persons;

I don't get it because the person.Password returns a string.

Could you please help me out, I spent a few hours on this problem but I can't get it fixed.

Regards,
Vincent Otterloo

[Zoran]

Hi Vincent,

The query you are executing looks like a valid one. Could you send us a sample project where this behavior is demonstrated so we can dig a bit deeper into the problem and in that case provide you with a decent solution.


Kind regards,
Zoran
the Telerik team

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[Brian Womack]

I banged my head on the wall for a better part of a day on the same problem in ORM version 2010.1.610.  It happens when you have a string property with only a 'get', which depends upon a transient field.  If you use mc.valStr in the LINQ expression below, you get the PC Parameter 0 transient error.  The code below works around the problem by creating a string temporary, mc_valStr.

I do have a 'SetTransient' function that I can call if the validity check fails (i.e. if _transient_val < 0 then call SetTransient).  This is a very good idea to maintain data integrity, but does not solve the problem.

[Telerik.OpenAccess.Transient()]
private int transient_val;

private string valStr;
[Telerik.OpenAccess.FieldAlias("valStr")]
public string ValStr
{
    get
    {
         if (_transient_val >= 0) return valStr = _transient_val.ToString();
         else return null;
     }
}

public static MyClass Find(IObjectScope scope, MyClass mc)
{
    if (mc == null) return null;
    else
    {
        string mc_valStr = mc.valStr;
        return (from d in scope.Extent<MyClass>()
                where
                d.valStr != null && d.valStr.Equals(mc_valStr, StringComparison.OrdinalIgnoreCase)
                select d).SingleOrDefault();
    }
}