Event Proccessing Questions

BlitzMax Forums/BlitzMax Programming/Event Proccessing Questions

Jay Kyburz

(Posted 2005) [#1]

Hey all,

I've been playing around with tree views and ran into something I don't really understand. Would appreciate some help getting my head around it.

When a GADGETACTION Event is called from a treeview, the EventData() is the treeViewNode that the user clicked on. I worked this out looking through the source of the MaxIDE.

What I don't understand is how EventData() is being converted to a Gadget.

Passing EventData() through a Function argument will convert it. eg

Function Convert:tGagdet (data:tGadget)
    Return data
End Function

Local thing:tGadget = Convert(EventData())
Notify thing.text 'etc

I would have thought you could somehow simply typecast the EventData() something like this..

local thing:tGadget = tGadget(EventData())

Can any of you programmers out there explain why passing it through a function works and perhaps suggest a cleaner method of converting the EventData to a Gadget.

Any help much appreciated.

Koriolis

(Posted 2005) [#2]

I have the feeling you've been bitten by the automatic int -> object conversion, and that the fact that the EventData() -> TGadget yielded a valid tgadget is puerly coincidence. Needless to say this isn't reliable.
I have barely started to toy with MaxGui, but I think the source gadget can be retrieved from the 'source' field of the event object.

Space_guy

(Posted 2005) [#3]

local thing:tGadget=SelectedTreeViewNode(Treeview)

i tore my hair on this one for quite a while. Is that what you needed?

Jay Kyburz

(Posted 2005) [#4]

Koriolis: The EventData()->tGadget is how the current IDE interprets messages from the tree view.

Space Guy: Thanks for the tip, I did see the function and was using it for a while, I just thought it would be "more correct" to read the data coming out of the event.