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TComboBox::DropDown

 
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Markus Klein
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PostPosted: Thu Sep 11, 2003 3:32 pm    Post subject: TComboBox::DropDown Reply with quote


Hello,

I derived a component from TComboBox and overwrote the method
DropDown. Now I would like to prevent in this function drop
down the ComboBox, or not. Is this the correct place for it?
Knows someone how I can realize that?

Thanks


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Remy Lebeau (TeamB)
Guest
PostPosted: Thu Sep 11, 2003 4:39 pm    Post subject: Re: TComboBox::DropDown Reply with quote



"Markus Klein" <markusklein (AT) justmail (DOT) de> wrote


Quote:
I derived a component from TComboBox and overwrote
the method DropDown. Now I would like to prevent in
this function drop down the ComboBox, or not. Is this
the correct place for it?

Post WM_CANCELMODE and CB_SHOWDROPDOWN messages to the ComboBox to cancel
the drop-down of the list.


Gambit





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Markus Klein
Guest
PostPosted: Fri Sep 12, 2003 8:37 am    Post subject: Re: TComboBox::DropDown Reply with quote


Thanks Gambit,

it works, but the ComboBox drops down and then close.
How can I realize, that the ComboBox do not drop down?

Thanks


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Remy Lebeau (TeamB)
Guest
PostPosted: Fri Sep 12, 2003 5:26 pm    Post subject: Re: TComboBox::DropDown Reply with quote

"Markus Klein" <markusklein (AT) justmail (DOT) de> wrote


Quote:
it works, but the ComboBox drops down and then close.

Are you using SendMessage() or PostMessage()? If the latter then try using
the former instead, or alternatively Perform().


Gambit


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Markus Klein
Guest
PostPosted: Tue Sep 30, 2003 9:25 am    Post subject: Re: TComboBox::DropDown Reply with quote
Hi,

I try CBO->Perform( CBN_CLOSEUP, 0, 0 ).
This has the same effect, how post the messages
WM_CANCELMODE and CB_SHOWDROPDOWN to the ComboBox.
Any Idea?

Thanks


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Salvador Huertas
Guest
PostPosted: Fri Oct 03, 2003 10:49 pm    Post subject: Re: TComboBox::DropDown Reply with quote
I had the same problem and solved it, overloading the WndProc function.

Here you had the code I used (Get by experimentation with the debugger):

void __fastcall TTreuComboBox::WndProc(Messages::TMessage &Message) {

if (Message.Msg==CN_COMMAND) {
if ((HWND)Message.LParam==Handle && (int)Message.WParamHi==CBN_DROPDOWN)
{
DropDown();
Message.Result=0;
pulsado=true;
return;
}
}
if (pulsado==true && Message.Msg==308) {
pulsado=false;
DroppedDown=false;
SendMessage(this->WindowHandle,513,0,0);
return;
}
TCustomComboBox::WndProc(Message);
}

Regards.
Salvador Huertas.
[email]shuertasw (AT) terra (DOT) es[/email]



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Remy Lebeau (TeamB)
Guest
PostPosted: Sat Oct 04, 2003 12:46 am    Post subject: Re: TComboBox::DropDown Reply with quote

"Salvador Huertas" <none@none> wrote


Quote:
if (pulsado==true && Message.Msg==308) {
snip
SendMessage(this->WindowHandle,513,0,0);

FYI, those messages are WM_CTLCOLORLISTBOX and WM_MOUSEMOVE, respectively:

if (pulsado==true && Message.Msg==WM_CTLCOLORLISTBOX)
...
SendMessage(Handle, WM_MOUSEMOVE, 0, 0);


Gambit



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