title: ObjectStateManager does not contain an ObjectStateEntry with a reference to an object of type
body: <p>I am using EISK (Employee Info Starter Kit) to develop an application. My entity diagram looks like this <img src="https://i.stack.imgur.com/qOEuW.jpg" alt="Entity Diagram"> I try to update the application table via this code.</p>
  
  <pre><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);
  </code></pre>
  
  <p>now the update method at bussiness logic is </p>
  
  <pre><code> [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);
  
      }
  </code></pre>
  
  <p>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.</p>