protected void btnVoid_Click(object sender, EventArgs e)
 {
     try
     {
         var    list     = contractProvider.GetActiveInvoices(lblContractNo.Text).ToList();
         string invoices = String.Empty;
         list.ForEach(inv => invoices += @"<li>" + inv.InvoiceNo + @"</li");
         if (list.Any())
         {
             WebFormHelper.SetLabelTextWithCssClass(
                 lblMessageAddEdit,
                 @"This contract has invoice already, please void invoice first: <ul>" + invoices + "</ul>",
                 LabelStyleNames.ErrorMessage);
         }
         else
         {
             contractProvider.VoidContract(lblContractNo.Text);
             mvwForm.SetActiveView(viwRead);
             WebFormHelper.SetLabelTextWithCssClass(
                 lblMessage,
                 @"Contract <b> " + lblContractNo.Text + "</b> has been processed as VOID",
                 LabelStyleNames.AlternateMessage);
             btnVoid.Enabled          = false;
             btnCloseContract.Enabled = false;
         }
     }
     catch (Exception ex)
     {
         mvwForm.SetActiveView(viwRead);
         WebFormHelper.SetLabelTextWithCssClass(lblMessage, ex.Message, LabelStyleNames.ErrorMessage);
     }
 }