Xdialog button events fire too many times

[EJR]

I would like to know if this is a bug or a feature, as it impacts development decisions for me. Any time I select any button, an event fires for all the buttons.

Run this xdialog below and watch the Trace window. Any time you select a button control, the "_changing" event fires for ALL the buttons, not just the one selected. And then a "_" (blank) event fires for the selected button. Perhaps it was never contemplated that someone would want to see all the events for a button control, but I do. Or maybe it's a known feature that I just stumbled upon. I'm using v10.5 build 3432-3608.

Please confirm if you see the same results, thanks.

'Buttons seem to fire events TWICE, including an 'unnamed' event
dim nTotal as n = 0
dim cTotal as c = "0"

ui_dlg_box("Buttons Fire Twice?",<<%dlg%
{lf=2};
{wrap=80}
When you TAB over to any of these buttons and press ENTER, events fire for ALL the buttons.;
{lf=1};
Is this a BUG or is it EXPECTED BEHAVIOR?
{lf=3};
{region}
	Click here to end the demo: | (EndDemo!EndDemo clicked);
	Total events that fired: | {text=10cTotal}
{endregion}
{lf=3};
{justify=center,center}
<25,2Button 1 - B1!B1_*> <35,2Any Text Here - B2!B2_*> <25,2And One More - B3!B3_*>;
<35,2Should be One Event Here - B4!B4>
%dlg%,<<%code%
nTotal = nTotal + 1					'See how many times we loop through there
cTotal = alltrim(str(nTotal))
trace.writeln("E:"+a_dlg_button+", Tot:"+nTotal)	'Show the event
if left(a_dlg_button,1) = "B"
	'Trap all those events here, then clear it so it loops continuously
	if right(a_dlg_button,1) = "_"
		trace.writeln("This event fired: " + a_dlg_button)
	end if
	a_dlg_button = ""
end if
%code%)

[G Gabriel]

Re: Xdialog button events fire too many times

No bugs.
Add this one to the pamphlet: "Mysteries of the xdlg"!
You got 2, Ira had one but my all time favorite is one by Mike Wilson.

The events are tied to buttons. Contrary to any other controls on the xdlg, once loaded, the buttons (all of them) are in a state of "changing", hence they all fire since you have an event attached to each of them and since you are not specific as to which event.

[CALocklin]

Re: Xdialog button events fire too many times

This is rather strange but that's also an incorrect usage of the event syntax.

I realize that you were probably trying to find out if there were other events for buttons but the use of an asterisk in a button event isn't supported because buttons only have one event. Since it isn't supported, the code isn't designed to handle it and that's why you are getting strange results.

If you remove the "*" from your event names you will get only one event triggered each time you push a button.

Also note that you were able to trap an "event" that ended with the underscore. This is probably because there is no event defined to replace the "*" when used in button events. In fact, buttons don't even need a specific event definition because the button text itself will be the event name.

The <25,2Button 1 - B1!B1_*> button in your script could be simply:
<25,2Button 1 - B1>
and the event name when pushed would be "Button 1 - B1".
However, I often add a specific event name to replace "complex" button text just to make life easier for me. In this case I'd probably use:
<25,2Button 1 - B1!btn1>
This would make typing easier AND I could change the button text without the need to change the event handling code - no matter what the text is, the event name remains "btn1". (I find that multi-word button text often gets "finessed" during development.) However, for a simple OK or Cancel button I don't bother adding an event name - typing <15OK!OK> just doesn't make sense to me.

Run the following code and you will note (A) button events only fire when the button is clicked and (B) the "*" in the event (sv_*) for the new field object will ALWAYS be replaced by some additional event name such as Changing, Changed, KillFocus, etc. The result is NEVER simply "sv_".

Button events don't fire twice anymore.
DIM nTotal as N = 0
DIM cTotal as C = "0"
ui_dlg_box( "Buttons Fire Twice?", <<%dlg%
{lf=2};
{wrap=80}
When you TAB over to any of these buttons and press ENTER, events fire for ALL the buttons.;
{lf=1};
Is this a BUG or is it EXPECTED BEHAVIOR?
{lf=3};
{region}
    Click here to end the demo: | (EndDemo!EndDemo clicked);
    Total events that fired: | {text=10cTotal};
    Field: [.20,1Some_Val!sv_*];
{endregion}
{lf=3};
{justify=center,center}
<25,2Button 1 - B1!B1_> <35,2Any Text Here - B2!B2_> <25,2And One More - B3!B3_>;
<35,2Should be One Event Here - B4!B4>
%dlg%,<<%code%
nTotal = nTotal + 1                    'See how many times we loop through there
cTotal = alltrim( str( nTotal ) )
trace.writeln( "E:" + a_dlg_button + ", Tot:" + nTotal )    'Show the event
IF left( a_dlg_button, 1 ) = "B"
    'Trap all those events here, then clear it so it loops continuously
    IF right( a_dlg_button, 1 ) = "_"
        trace.writeln( "This event fired: " + a_dlg_button )
    END IF
    a_dlg_button = ""
ELSEIF left( a_dlg_button, 3 ) = "sv_"
    trace.writeln( "This event fired: " + a_dlg_button )
    a_dlg_button = ""
END IF
%code% )

[EJR]

Re: Xdialog button events fire too many times

Thanks, Cal, but... I copied your code and if you TAB or SHIFT-TAB to a button and press ENTER, the button event fires twice.

You are correct that I was playing with things to see how far I could go since I wanted to understand AlphaFive better (I used to program in C and assembly and that would get me into LOTS of trouble!). So I have no fear trying things I shouldn't do. And I'll have lots more fun when I start creating DLLS with FASM to speed up some text-manipulation tasks in A5.

I think I agree with you and G. that this is probably not a bug that needs to be addressed, as it is undocumented, so "unpredictable results" are fair game. But there is one part of this that I'm still thinking about, though it also may not be a bug.

If you click on a button and query with ui_dlg_clt_current, the control reported as "current" is the one where the cursor was immediately before you clicked. But if you TAB to the button and press ENTER (or click), you are told that the button you are selecting is the current control. (And sometimes the control name is returned with a CR/LF + TAB in front.) Rereading what I just wrote here, this is probably a good design - clicking a control probably shouldn't change focus, whereas tabbing should. (But adding CR/LF/TAB in front??)

Again, thanks for spending time on this. I'm fine with the current behavior, but wanted to know if this was considered a bug (in which case the behavior would change) or not (in which case I can depend on what I now know is going on).

[G Gabriel]

Re: Xdialog button events fire too many times

In other applications.. javascript for instance, buttons have several events. In alpha, more specifically in xdlg, you could only press the button and that's that.

I don't know where you dream these things up (and I mean that as a complement) because you unearth these intricacies about the xdlg with these schemes. Adding these events to the buttons with virtually identical events' names unearthed the fact that in alpha when an xdlg is loaded the button is in a "changing" state. Well, yeh.. it is.. it is waiting for you to do something..or nothing. One might philosophize the merit behind that, and whether it should be in a changing state at all, but I wouldn't call it a bug. If you were to follow "proper" coding, i.e. why would you want to have names in common for different events in different buttons? and why would you want to trap a button event? In alpha, in xdlg that is? If you just follow the norms and give the button event a distinct name you wouldn't run into this. I am glad you did though.

But there is one part of this that I'm still thinking about, though it also may not be a bug.

If you click on a button and query with ui_dlg_clt_current, the control reported as "current" is the one where the cursor was immediately before you clicked. But if you TAB to the button and press ENTER (or click), you are told that the button you are selecting is the current control.

Once again, this is one of those subtilties. Someone asked a similar question recently in a different thread and I explained the difference.

[EJR]

Re: Xdialog button events fire too many times

Thanks for the compliment. I "dream these things up" because I want to know how things work and I like to just jump in and then, if I'm hopelessly lost, I'll search for the answer. I'm learning fast because I keep pushing myself, and it's great to have people such as yourself and the others who are regulars on this forum. And if I can help somebody else skip over the problems I've run into, I feel better.

And here's the clincher that I think is good for all A5 users: almost invariably, when I think I've found a pesky little bug, it turns out I didn't understand the big picture, and my design or implementation was at fault. And I've seen this happen with many others, too. And even though I have found a couple of real bugs that have been/are being fixed, this is helping me feel more and more comfortable with A5.