// When lease is clicked, get slip and cust ID, instantiate new lease, add it to DB and refresh view.
        protected void uxLease_Click(object sender, EventArgs e)
        {
            int slipID = Convert.ToInt32(uxSlips.SelectedValue);
            int custID;

            if (Request.Cookies["CustomerID"] != null)
            {
                custID = Convert.ToInt32(Request.Cookies["CustomerID"].Value);
            }
            else if (Session["customerID"] != null)
            {
                // Get customer ID from session.
                custID = (int)Session["customerID"];
            }
            else // display message if cookies are disabled and session custID doesn't exist.
            {
                uxMessage.Text = "Something went wrong, please log out and log in again.";
                return;
            }

            // instantiate new lease and add it to DB, then bind.
            Lease newLease = new Lease
            {
                CustomerID = custID,
                SlipID     = slipID
            };

            mgr.LeaseSlip(newLease);

            GetAvailableSlips(Convert.ToInt32(DockSelector.SelectedDockID));
        }