CreateWindow COMBOBOX without any CBS_ style set : what am I getting ?

[R.Wieser]

Hello all,

I'm putting a combobox onto a dialog using CreateWindowEx, only setting the
WS_VISIBLE and WS_CHILD styles (no CBS_* ones). As a result I get something
that looks the same as if I specified the CBS_DROPDOWN style.

Question : what am I actually getting / whats the difference between no
style and the CBS_DROPDOW one ?

Regards,
Rudy Wieser

[JJ]

Considering that a combobox can only have 3 main styles where all of them
are non zero, it has to have a default style to represent style with zero
value. That default style is CBS_SIMPLE. Whether CBS_SIMPLE is specified or
not when the control is created, and whether the style value of the created
control actually has CBS_SIMPLE or not. It's kind of weird, but that's just
how it is.

Some controls would complain if they're created with an invalid style, but
at least combobox, doesn't complain.

[R.Wieser]

JJ,

> Considering that a combobox can only have 3 main styles where all
> of them are non zero, it has to have a default style to represent
> style with zero value.

:-) You're working your way back from the answer to the question, instead
of starting with the question and try to figure out what the answer is.

So no, I don't agree with either. 3 is not some magical number and a
"default style" is, to me, just the 'unspecified behaviour' you're left with
when you've handled all specified cases.

> It's kind of weird, but that's just how it is.

I know it is. Starting with two style values doing the exact same thing is
odd. I could have accepted it at the end of the range (styles 4 and
higher - there seem to room for 16 styles), but not the start. Thats why I
was asking. :-)

Regards,
Rudy Wieser

[JJ]

On Sun, 25 Dec 2022 19:49:39 +0100, R.Wieser wrote:
>
> I know it is. Starting with two style values doing the exact same thing is
> odd. I could have accepted it at the end of the range (styles 4 and
> higher - there seem to room for 16 styles), but not the start. Thats why I
> was asking. :-)
>
> Regards,
> Rudy Wieser

Well, only Microsoft knows why the main style value starts from 1 instead of
0.

[R.Wieser]

"JJ" <jj4p...@outlook.com> wrote in message
news:cuzdapnd05jl$.17yf0pb3dgpym.dlg@40tude.net...

> Well, only Microsoft knows why the main style value starts from 1
> instead of 0.

I was hoping someone else, hopefully present in this newsgroup, would know
too. Alas.

By the way, I probably will throw all the 16 values at it to see if I can
spot a pattern. Perhaps I will even find another undocumented style !

And thanks for the reply - even though I seldom seem to be agreeing with you
... :-)

Regards,
Rudy Wieser