Quickly check which part of the page lifecycle a control is in

Question

Is there any way to check what events have fired during the asp.net webforms page/control lifecycle?

I know that I can manually add handlers for each event, but that seems a bit ... inefficient.

Is there a visualiser, or a property that I can check that will tell me whether these events have fired?

EDIT The reason I want to know this is that I am overriding the ViewState property of a custom control, and the viewstate disappears at some point, and I'd like to know at which point in the page lifecycle it is being overriden.

Answer 1

The way events work in .NET is that you register you interest in them, and the framework will call your handler when they are fired. I'm not aware of any visualiser or property that tells you where you are in the life cycle, other than knowing where you are.

On MSDN, ASP.NET Page Life Cycle Overview gives a pretty good description of what happens when, and as everything you do in the page or on a control will be as part of handler of one of those events, you should be able to work out where in the process you are.

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Edit to add

The SaveStateComplete event is raised once all controls etc have finished saving their details to the ViewState - this is where your code should probably go.

Controls can make changes to the ViewState up to that point - and generally will be doing so in the PreRender event (which fires just before SaveStateComplete).

What sort of changes are you making?

Answer 2

Page and control events fire in a very strict, very predictable fashion. The Page and all controls handle one event before moving on to the next one. So if you put your code in the Page, you can know exactly what has happened in all associated controls.

However, overriding ViewState directly isn't safe; controls depend on it. Instead, you might look at overriding SavePageStateToPersistenceMedium() and LoadPageStateFromPersistenceMedium() on the Page; they give you a lot of control over the ultimate disposition of ViewState.

In case it helps, I cover those methods and other related optimizations in my book: Ultra-Fast ASP.NET.

Answer 3

Once again, I'm answering my own question.

What I wanted to do was to determine what events had fired in the page life cycle.

This is actually pretty trivial: Enable tracing in the web.config, and then go to ~/Trace.axd to see what had fired.