private void btnInvoiceAddItem_Click(object sender, EventArgs e)
        {
            frmInvoiceItem fo = new frmInvoiceItem();

            fo.strAction  = "NEWITEM";
            fo.Invoice_ID = long.Parse(this.txtInvoiceNo.Text.ToString());
            fo.ShowDialog();
            RefreshInvoiceList(Invoice_ID);
            RefreshInvoiceAggregations(Invoice_ID);
        }
 private void btnInvoiceEditItem_Click(object sender, EventArgs e)
 {
     if (this.dataGridView1.RowCount != 0)
     {
         if (this.dataGridView1.SelectedRows.Count != 0)
         {
             frmInvoiceItem fo = new frmInvoiceItem();
             fo.strAction = "EDITITEM";
             fo.ShowDialog();
             RefreshInvoiceList(Invoice_ID);
         }
     }
 }