private void btnAdd_Click(object sender, EventArgs e)
        {
            try
            {
                DataClassesJobDataContext db = new DataClassesJobDataContext();
                InterviewDetail           interviewDetail = new InterviewDetail();
                //check if item already exists in sales detail table with same transId
                //var item = from i in db.ApplyJobDetails
                //           where i.ItemId.Equals(DropDownListItemName.SelectedItem.Value) && i.SaleId == LabelSaleId.Text
                //           select i;
                //if (item.Any())
                //{
                //    LabelMessage.ForeColor = System.Drawing.Color.Red;
                //    LabelMessage.Text = DropDownListItemName.SelectedItem.Text + " already exists. please update or delete it to make a new entry";
                //    // txtNetTotal.Text = "0";
                //    return;
                //}
                // generate Sale Id manually by random
                // var random = Guid.NewGuid().ToString().Replace("-", null);
                if (cboId.Text == "*" || cboId.Text == "")
                {
                    MessageBox.Show("please click the new button");
                    return;
                }


                /*
                 * vendor.ItemTypeId = Convert.ToInt32(DropDownList1.SelectedItem.Value);
                 *  vendor.itemTypeName = DropDownList1.SelectedItem.Text;
                 *
                 * insert data into master table (sale) before inserting data into child table(saleDetail)
                 */



                #region insert data into master tabel
                // insert data into master table
                var queryResults = from s in db.Interviews
                                   where s.Id == cboId.Text
                                   select s;
                if (queryResults.Any())
                {
                    // MessageBox.Show("id already exists");
                    // return;
                    goto childTable;
                }
                else
                {
                    //insert new  transId
                    Interview interview = new Interview();
                    interview.Id          = cboId.Text;
                    interview.TransDate   = dtpTransDate.Value;
                    interview.CompanyId   = Convert.ToInt32(cboCompany.SelectedValue);
                    interview.CompanyName = cboCompany.Text;

                    db.Interviews.InsertOnSubmit(interview);
                    db.SubmitChanges();
                }
                #endregion
childTable:
                interviewDetail.InterviewId = cboId.Text;
                interviewDetail.QuestionId  = (int)cboQuestion.SelectedValue;
                interviewDetail.Question    = cboQuestion.Text;

                db.InterviewDetails.InsertOnSubmit(interviewDetail);
                db.SubmitChanges();
                MessageBox.Show("item added in detail");


                // bind saleDetail data to grid view


                var interDetail = from s in db.InterviewDetails
                                  where s.InterviewId == cboId.Text
                                  select s;
                // var list = new List<object> { queryResults };
                dataGridViewQuestion.DataSource = interDetail;
                // show notification for delete
                notifyIconRightClick.ShowBalloonTip(3, "Tip", "right click on datagrid to get context menu", ToolTipIcon.Info);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
 partial void UpdateInterview(Interview instance);
 partial void DeleteInterview(Interview instance);
 partial void InsertInterview(Interview instance);