Visual Basic - Scrollable Container - Set LargeChange property bug

Author

Scrollable Container - Set LargeChange property bug

Brian Stigler

2004-05-28, 7:30 pm

Hi folks...
I've implemented a rather simple vertical-only scrollable container using
two picture boxes. The container receives a varying number of "frame"
components stacked one below another. The scroll container only fills half
of the form with other info filling the top half.

So... depending on the size of the form window, the scroll container (half
of the form height) can display only a limited number of all the frames in
the scroll box. My plan is to set the largechange property to be equal to
an integer value of the number of visible frames... (if a frame height was
200, and the scroll container region height was 860, then the largerchange
property would be Int(860/200)*200. (I also check to see if there are at
least twice as many frames as the visible count and only set the largechange
if this is the case.)

Here's my problem... every once in a while, my vertical scroll bar just
disappears! It seems related to how the largechange property is set. I
haven't been able to track down where this problem occurs or why exactly...

Can anyone shed some light on why this might be happening??? I would think
that I could set my large change to be just about anything I wanted... but
that doesn't seem to be the case... Any help would be appreciated.

Thanks,
Brian

Larry Serflaten

2004-05-28, 7:30 pm

"Brian Stigler" <bkstigler@usa.net> wrote
> Hi folks...
> I've implemented a rather simple vertical-only scrollable container using
> two picture boxes. The container receives a varying number of "frame"
> components stacked one below another. The scroll container only fills half
> of the form with other info filling the top half.
>
> So... depending on the size of the form window, the scroll container (half
> of the form height) can display only a limited number of all the frames in
> the scroll box. My plan is to set the largechange property to be equal to
> an integer value of the number of visible frames... (if a frame height was
> 200, and the scroll container region height was 860, then the largerchange
> property would be Int(860/200)*200. (I also check to see if there are at
> least twice as many frames as the visible count and only set the largechange
> if this is the case.)
>
> Here's my problem... every once in a while, my vertical scroll bar just
> disappears! It seems related to how the largechange property is set. I
> haven't been able to track down where this problem occurs or why exactly...
>
> Can anyone shed some light on why this might be happening??? I would think
> that I could set my large change to be just about anything I wanted... but
> that doesn't seem to be the case... Any help would be appreciated.

Does it actually go invisible, or does it get hidded by some other control?

If it goes invisible, you might add a watch for that scrollbar's Visible property
to have your program break when the Visible property changes. But, unless
you have code that sets the Visible property, that may not be the problem,
it may just be moved out of view, or hidden behind some other control.

The best thing to do for us, is to make a small demo that reproduces the
problem, and post that code so we can see it on our own machines. There
is a good chance that the act of trying to make such a demo, actually helps
you find the problem, and if not, you have a demo you can post for others
to look at....

LFS

Brian Stigler

2004-05-31, 1:30 am

Thanks for the suggestions Larry... I did check the visible property and
that isn't the problem... I also don't believe that the control is hidden
as there are no sizing changes occuring... (that I'm aware of... I'll try
to post a demo shortly that demonstrates the issue....

Again, thanks.
Brian

"Larry Serflaten" <serflaten@usinternet.com> wrote in message
news:egD$PUQREHA.808@tk2msftngp13.phx.gbl...
>
> "Brian Stigler" <bkstigler@usa.net> wrote
using[color=darkred]
half[color=darkred]
(half[color=darkred]
in[color=darkred]
to[color=darkred]
was[color=darkred]
largerchange[color=darkred]
at[color=darkred]
largechange[color=darkred]
exactly...[color=darkred]
think[color=darkred]
but[color=darkred]
>
>
> Does it actually go invisible, or does it get hidded by some other
control?
>
> If it goes invisible, you might add a watch for that scrollbar's Visible
property
> to have your program break when the Visible property changes. But, unless
> you have code that sets the Visible property, that may not be the problem,
> it may just be moved out of view, or hidden behind some other control.
>
> The best thing to do for us, is to make a small demo that reproduces the
> problem, and post that code so we can see it on our own machines. There
> is a good chance that the act of trying to make such a demo, actually
helps
> you find the problem, and if not, you have a demo you can post for others
> to look at....
>
> LFS
>
>

Sponsored Links