[IronPython] WPF/IronPython event handlers question - multiple event handlers

[Michael Foord]

On 07/06/2010 21:26, Ken MacDonald wrote:
> Hi,
> I've got a whole stack of event handlers, assigned via the usual 
> something like....
>
> my_button.Click += button_was_clicked
>
> As it turns out, the initialization for the thing that has all these 
> handlers may need to be run several times, and it seems like I ended 
> up with multiple copies of the same event handler, and 
> "button_was_clicked()" now gets invoked multiple times for EACH time I 
> click my_button. It seems to be solved by just skipping the handler 
> assignment if I've already done it before, but it seems odd that the 
> same EH would be assigned and fired twice. 

It would seem odder to me if you added an event handler multiple times 
and it *wasn't* called. :-)

The less programming languages read your mind and work out what they 
*think* you meant the better. If you don't want an event handler 
installed multiple times then don't add it multiple times...

Michael Foord

> Is this really what I'm seeing? I can see a case for assigning 
> multiple *different* EH's:
>
> my_button.Click += event_handler_1
> my_button.Click += event_handler_2
>
> but then this begs the question, is there a defined order in which the 
> EH's will fire? I looked thru multiple python/IronPython books and 
> googled, but came up empty on both questions..... Hopefully someone 
> here understands these things better than I do....
> Ken
>
>
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>    


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