WithEvents ???

[Guest]

Is there any additional overhead for declaring a variable using the
WithEvents keyword even if none of the events are being handled?

 

[Scott M.]

I would imagine yes, but I can't give specifics.

 

[Herfried K. Wagner [MVP]]

Is there any additional overhead for declaring a variable using the
WithEvents keyword even if none of the events are being handled?

What do you mean by "overhead"? Maybe a little overhead, but you don't
need to care about that.

 

[NoOne]

Is it possible that its just a keyword for the visual basic compiler that
connects an object's events to some handlers? C# and Visual Basic both
compile to IL, if it did have overhead (other than compilation) it would
have to show up there.

 

[solex]

I am pondering here but would imagine that there is no overhead because I
would again imagine that the MSIL compiler is very efficient and would
realize that there are no eventsinks for the object and hence remove and
event handling code.

A question for you is why would you declare an object withEvents if you do
not plan on using them?

 

[Tom Spink]

Hi NoOne,

You are correct, WithEvents (in conjuction with the Handles clause) removes
the arduous task of AddHandler and RemoveHandler on all events for any
controls you make.

--
HTH,
-- Tom Spink, Über Geek

Please respond to the newsgroup,
so all can benefit

" System.Reflection Master "

==== Converting to 2002 ====
Remove inline declarations

 

[Armin Zingler]

Is there any additional overhead for declaring a variable using
the WithEvents keyword even if none of the events are being
handled?

As it's already been mentioned, Withevents does Addhandler/removehandler
internally for you.

Variables declared with Withevents are actually properties.

Writing

private withevents cmd as button

sub cmd_click(...) handles cmd.Click
end sub


is exactly the same as

private _cmd as button

private property cmd() as button
get
return _cmd
end get
set (byval value as button)
if not _cmd is nothing then
removehandler _cmd.click, addressof cmd_click
end if
_cmd = value
if not _cmd is nothing then
addhandler _cmd.click, addressof cmd_click
end if
end set
end property


The more "Handles" procedures, the more removehandler/addhandler statements
are created.