ObjectStateManager does not contain an ObjectStateEntry with a reference to an object of type

Question

I am using EISK (Employee Info Starter Kit) to develop an application. My entity diagram looks like this I try to update the application table via this code.

           int apId = Convert.ToInt32(Request.QueryString["ApplicationID"]);

            ApplicationBLL objGetApplication = new ApplicationBLL();

            Appdec.YEP.BusinessEntities.Application objApplication =
            objGetApplication.GetApplicationByApplicationID(apId);



            objApplication.Status = (ddlStatus.SelectedValue == "0" ? false : true);



            new ApplicationBLL(new Appdec.YEP.DataAccessLayer.DatabaseContext()).UpdateApplication(objApplication);

now the update method at bussiness logic is

 [System.ComponentModel.DataObjectMethodAttribute(System.ComponentModel.DataObjectMethodType.Update, true)]
    public void UpdateApplication(Application updatedApplication)
    {
        // Validate Parameters
        if (updatedApplication == null)
            throw (new ArgumentNullException("updatedApplication"));

        // Validate Primary key value
        if (updatedApplication.ApplicationID.IsInvalidKey())
            BusinessLayerHelper.ThrowErrorForInvalidDataKey("ApplicationID");

        // Apply business rules
        OnApplicationSaving(updatedApplication);
        OnApplicationUpdating(updatedApplication);

        //attaching and making ready for parsistance
        if (updatedApplication.EntityState == EntityState.Detached)
            _DatabaseContext.Applications.Attach(updatedApplication);



_DatabaseContext.ObjectStateManager.ChangeObjectState(updatedApplication, System.Data.EntityState.Modified);//this line throws the error 
//ObjectStateManager does not contain an ObjectStateEntry with a reference to an object of type
        int numberOfAffectedRows = _DatabaseContext.SaveChanges();
        if (numberOfAffectedRows == 0) 
            throw new DataNotUpdatedException("No application updated!");

        //Apply business workflow
        OnApplicationUpdated(updatedApplication);
        OnApplicationSaved(updatedApplication);

    }

Can somebody tell me how to fix this error and update the tables. the same error ocurres when i try to update other tables also. The insert works fine. Hoping not to bother you. Best Regards.

Solution

So it already belongs to a context,and you should update that context. It can't be attached to new context, You can create a new instance of updatedApplication and copy all properties of updatedApplication to this new one and attach new entity to application.

Also change

  if (newApp .EntityState == EntityState.Detached)
            _DatabaseContext.Applications.Attach(newApp );

to

var newApp = Application ();
 //Copy all propery of updatedApplication to  newApp here 

            if (newApp .EntityKey == null || newApp .EntityKey.IsTemporary)
            {
                _DatabaseContext.Applications.AddObject(newApp );
            }
            else
            {
                _DatabaseContext.Applications.Attach(newApp );
            }
_DatabaseContext.ObjectStateManager.ChangeObjectState(newApp , System.Data.EntityState.Modified);