protected void SelectVendor_Click(object sender, EventArgs e)
 {
     if (VendorList.SelectedIndex == 0)
     {
         MessageUserControl.ShowInfo("Select Error", "You must select a vendor.");
         Subtotal.Text = "0.00";
         Tax.Text      = "0.00";
         Total.Text    = "0.00";
         Cancel_Click(sender, e);
     }
     else
     {
         MessageUserControl.TryRun(() =>
         {
             int vendorid = int.Parse(VendorList.SelectedValue);
             PurchasingController sysmgr = new PurchasingController();
             VendorInfo newinfo          = sysmgr.Vendor_Info(vendorid);
             VName.Text    = newinfo.VendorName;
             Contact.Text  = newinfo.Contact;
             Phone.Text    = newinfo.Phone;
             Comments.Text = newinfo.Comments;
             List <PurchaseOrder> order = sysmgr.Purchase_Order(vendorid);
             PurchaseOrderGV.DataSource = order;
             PurchaseOrderGV.DataBind();
             calculatePOValue();
             List <ProdCategoryInfo> inventory = sysmgr.ProdCategory_List(vendorid);
             ProdCatListDTO.DataSource         = inventory;
             ProdCatListDTO.DataBind();
         }, "Purchase Order Info", "Create purchase order for this vendor.");
     }
 }
        protected void Cancel_Click(object sender, EventArgs e)
        {
            VendorList.SelectedValue = "0";
            VName.Text              = "";
            Contact.Text            = "";
            Phone.Text              = "";
            Comments.Text           = "";
            UsersList.SelectedValue = "0";

            List <PurchaseOrder> emptypo = null;

            PurchaseOrderGV.DataSource = emptypo;
            PurchaseOrderGV.DataBind();

            List <ProdCategoryInfo> emptyinv = null;

            ProdCatListDTO.DataSource = emptyinv;
            ProdCatListDTO.DataBind();
            calculatePOValue();
        }