The first thing to understand is how to add trace messages to ASP.NET pages. All you must do is add a Trace=True attribute to the @page directive at the top of the ASPX page, as follows:
<%@ Page language=”c#” Trace=”true” Codebehind=”WebForm1.aspx.cs” AutoEventWireup=”false” Inherits=”Chapter22.WebForm1” %>
Adding the Trace=True attribute ASP.NET generates extensive information about requests made to that page and appends it as part of a page rendering, as shown in Figure 22.1.
Consider for a minute what kind of information ...