vb.net - Asp.net control with custom event -
i have control has custom event.
currently define other event
public event contentchanged eventhandler
but today found article had totally different way of handling it
shared readonly contentchangedkey new object() public custom event contentchanged eventhandler addhandler(value eventhandler) me.events.addhandler(contentchangedkey, value) end addhandler removehandler(value eventhandler) me.events.removehandler(contentchangedkey, value) end removehandler raiseevent(sender object, e eventargs) dim contentchangeddelegate eventhandler = _ me.events(contentchangedkey) contentchangeddelegate(sender, e) end raiseevent end event
the second way seems overly complicated first example doesn't??
it has overcomplication :)
in other words can add in there other kind of processing needs done when envent happens or bound to. since controlling actions taken when event handler added, removed or raised, can custom things.
for example had control had 5 buttons. 1 of buttons usless unless event x being handled.
with custom event handler this:
public custom event contentchanged eventhandler addhandler(value eventhandler) me.events.addhandler(contentchangedkey, value) me.specialbutton.visible = true end addhandler removehandler(value eventhandler) me.events.removehandler(contentchangedkey, value) me.specialbutton.visible = false end removehandler raiseevent(sender object, e eventargs) dim contentchangeddelegate eventhandler = _ me.events(contentchangedkey) contentchangeddelegate(sender, e) end raiseevent end event
if did not have custom event handler difficult kind of logic. comes down granularity; how control need?
of course need sure when addhandler
or removehandler
being triggered expect use in there real. this overly simplified example
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