Re: Exception handling suggestions

On Mar 11, 5:30 pm, "Zytan" <zytanlith...@xxxxxxxxx> wrote:
main
{
AppDomain.CurrentDomain.UnhandledException+=new
UnhandledExceptionEventHandler(CurrentDomain_UnhandledException);
Application.Run(new MyFirstForm());
}

Ok, if this is for a windows app, what is "main"? The main form's
constructor? After InitializeComponent? No it can't be, because you
are running the first form from this. Ah, it's in Program.cs! So, I
have to change this file, and add that event handler addition line, I
see.

You can add the event handler anywhere, but it's best to do it as
early as possible so that the minimum amount of code runs before the
handler is hooked up.

There is also the Application.ThreadException event. I always handle
them both.

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemwindowsformsapplicationclassthreadexceptiontopic.asp

Main, by the way, is the main entry point into any application,
console or WinForms. It is usually the first piece of your code that
the CLR calls, and it's usually where you set up global exception
handlers.

Ok, Application.Run(new MyFirstForm()) does work here! It doesn't in
a console app. It is really System.Windows.Forms.Application. I see.

private static void CurrentDomain_UnhandledException(object sender,
UnhandledExceptionEventArgs e)
{
// The app shuts down.., you can log here..

//After log exit
Application.Exit();
}

I presume this code must also go in Program.cs?

Well, not necessarily. For example, I have mine in a standard error
logging class, and from my Main I call something like:

ErrorLog.Instance.SetupConsoleErrorHandling();

and inside there I subscribe to the events and the ErrorLog class
contains the event handler methods. Nonetheless, that's just because I
wanted a reusable utility. You can also have the method in your main
program .cs file. Nothing wrong with that.


Finally, I would like to offer some general advice on catching
exceptions: catch only what you can handle. Or, put another way, don't
catch an exception unless you can take some substantial action
regarding it. There are other threads in this newsgroup on exception
handling... when and how to catch an exception, but I wanted to point
that out because it explains why you (almost) never catch (Exception
ex): because it's very rare that you can take some intelligent action
with any exception that could possible happen.

The exception to that rule, of course, being logging, and that's what
global exception handlers are for.

.

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