private void btnAddDetail_Click(object sender, EventArgs e)
        {
            if (contractDetail != null)
            {
                contractDetail.Id = 0;
            }
            ContractItemDetailForm contractDetailDetailForm = new ContractItemDetailForm(contractDetail);

            contractDetailDetailForm.FormClosed += new FormClosedEventHandler(DetailForm_Closed);
            contractDetailDetailForm.ShowDialog();
        }
 private void btnViewDtail_Click(object sender, EventArgs e)
 {
     if (contractDetail != null)
     {
         if (contractDetail.Id != 0)
         {
             ContractItemDetailForm detailForm = new ContractItemDetailForm(contractDetail);
             detailForm.FormClosed += new FormClosedEventHandler(DetailForm_Closed);
             detailForm.ShowDialog();
         }
     }
 }