Asp.Net page life-cycle - What tool ( perhaps Reflector?) would enable me to view the order in which page events and their event handlers are called...

Question

1) I know there are lots of web sites that describe in what order events are called during the Asp.Net page life-cycle. But is there also a tool, perhaps Reflector, that would enable me to figure out by myself in what order are ALL the page’s events and their event handlers called during the page’s life cycle?

2) Would you say that trying to figure out exactly what is going on under the hood is a good idea or a waste of time? To clarify – I’d like to figure out exactly what is going on when a control tree is build – thus all the method calls, all the events called etc needed for control tree to be build ( I imagine there are hundreds or perhaps thousands lines of code written just for building a control tree).

thanx

Answer 1

ASP.net Tracing would be the one I'd go for. It'll show you when each method in your page/control is called and you can also output additional data to the trace as well. It's primarily intended (I guess!) as a debugging tool, but I think it'll be more than adequate to show you the exact lifecycle a page is undertaking.

To turn on tracing, add the following to your web.config file:

 <trace enabled="true" pageOutput="true" requestLimit="10" traceMode="SortByTime" localOnly="true" />

As Jim Schubert pointed out in a comment, you can also modify the @page directive of a specific page to enable tracing:

 <%@ Page Title="" Trace="true"......

You can then access the trace details by navigating to "Trace.axd". If you're using a remote server (i.e. not Cassini or IIS on localhost) then change the localonly="true" to localonly="false" in the snippet above.

Having an understanding of what goes on under the hood in WebForms can be very useful, it certainly makes solving some of the oddities and edge-cases a lot easier.

Answer 2

Enabling trace might help you to understand the page life cycle. You'll see the page events that's called while ASP.NET renders the page.

Try simply this, and take a look at your page's bottom :

<%@ Page Language="C#" Trace="true"  %>

Answer 3

IMHO, you should understand what is happening in the page lifecycle, to develop a decent application. Knowing only helps, can't hurt. And once you understand, you can design hi-performing applications (knowing that not all modules are needed for your application). See this - for asp.net performance tuning.

Here is a good low level explanation from Rikh Strahl. Look at this diagram, you can understand them better.

Answer 4

1) Put a breakpoint in the constructor of the page, then step through the code (F10) to see in which order your code runs. Alternatively, put breakpoints in all events and see in which order they are hit.

2) The definition of time waste depends on what time you are spending and why you would need the information. Generally you should not dig much deeper than what you need for completing the task at hand. The platform is designed so that you don't have to know much at all about what's happening behind the scene to use it.

If it's just for curiosity, then you just have to decide how much of your time you want to waste on it.