Row not found or changed.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Data.Linq.ChangeConflictException: Row not found or changed.

 protected void GridGoalContent_RowUpdated(object sender, GridViewUpdatedEventArgs e)
        {
            int curGoalContentID = (int)e.Keys["GoalContentID"];

            using (NoticeDataContext ndc = new NoticeDataContext())
            {
                Plan_GoalContent plan = (from data in ndc.Plan_GoalContents
                                         where (data.GoalContentID == curGoalContentID)
                                         select data).FirstOrDefault<Plan_GoalContent>();
                if (plan != null)
                {

                    plan.GoalContentName =(e.NewValues["GoalContentName"] != null) ? e.NewValues["GoalContentName"].ToString().Trim():null;
                    plan.CriteriaName = (e.NewValues["CriteriaName"] !=null) ? e.NewValues["CriteriaName"].ToString().Trim():null;
                    plan.ExpectedResultText = (e.NewValues["ExpectedResultText"] != null) ? e.NewValues["ExpectedResultText"].ToString().Trim() : null;
                    plan.ExpectedData = GetDatePlan(e.NewValues["ExpectedData"]);
                    plan.ResultData = GetDatePlan(e.NewValues["ResultData"]);
                    plan.Result = (e.NewValues["Result"] != null) ? e.NewValues["Result"].ToString().Trim() : null;
                    plan.Comment = (e.NewValues["Comment"] != null) ? e.NewValues["Comment"].ToString().Trim() : null;
                    ndc.SubmitChanges();

                }
            }
        }