สอบถามหน่อยครับ พอดีจะ insert Date จาก Xtragrid Devexpress ลงในฐานข้อมูล SQL Server

   private void btnadd_Click(object sender, EventArgs e)
        {
            

            string leave_id = "";
            string leave_typename = "";
            string leave_start = "";
            string leave_stop = "";
            string leave_sumtime = "";
            string employee_ID = "";


            try
            {

                for (int i = 0; i < gridView1.DataRowCount; i++)
                {
                    leave_id = Convert.ToString(gridView1.GetRowCellValue(i, "leave_id"));
                    leave_typename = Convert.ToString(gridView1.GetRowCellValue(i, "leave_typename"));
                    leave_start = Convert.ToString(gridView1.GetRowCellValue(i,"leave_start"));
                    leave_stop = Convert.ToString(gridView1.GetRowCellValue(i, "leave_stop"));
                    leave_sumtime = Convert.ToString(gridView1.GetRowCellValue(i, "leave_sumtime"));
                    employee_ID = Convert.ToString(gridView1.GetRowCellValue(i, "employee_ID"));

                    
                }
                                       
                string sqluser = "INSERT INTO tbl_Leave(leave_typename,leave_start,leave_stop,leave_sumtime,employee_ID) VALUES('" + leave_typename + "','" +leave_start+ "','" + leave_stop + "','" + leave_sumtime + "','" + employee_ID + "')";
                connect_db.ExcuteData(sqluser);
                showdgvmainleave();
                MessageBox.Show("บันทึกข้อมูล สำเร็จ !");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }
        }