CDialog::PreCreateWindow is never called
Claus Michelsen -- cmi@cri.dk
Wednesday, January 29, 1997
Environment: VC++ 4.2-flat, Win 95
I have created a CDialog-derived class with ClassWizard and have overriden
PreCreateWindow but it is never called. How is that?
I have tried to start the dialog box with both DoModal and Create.
Thanks!
Best regards,
Claus Michelsen
CRI A/S, Denmark
Dinesh Jindal -- dinesh@XOX.com
Thursday, January 30, 1997
[Mini-digest: 4 responses]
I think this issue has already been discussed on this list couple of
weeks ago.
Anyway, the reason PreCreateWindow is not called for Dialog boxes is
that this function is not in response to any WM_XXXX message. This is
simply a overridable function provided by MFC classes derived from CWnd
and gets called by MFC directly whenever it creates a window. CView,
CFrameWnd etc gets created by framework and PreCreateWindow gets called
before actual creation. Other windows ( controls, dialog box or
window created by CreateWindow...) get created directly by WINDOWS
without any involvement of MFC, so MFC never gets a chance to call this
function.
This behavior is not at all unexpected. You need to know about
PreCreateWindow only when some window is getting created behind the
scene. I don't understand why anybody needs PreCreateWindow if
application is directly creating a window explicitly. You may
very well change anything you want in CREATESTRUCT or by changing the
arguements to CreateWindow..
Cheers!
Dinesh Jindal
Claus Michelsen wrote:
>
> Environment: VC++ 4.2-flat, Win 95
>
> I have created a CDialog-derived class with ClassWizard and have overriden
> PreCreateWindow but it is never called. How is that?
>
> I have tried to start the dialog box with both DoModal and Create.
>
> Thanks!
>
> Best regards,
> Claus Michelsen
> CRI A/S, Denmark
-----From: stas
Hi Claus,
PreCreateWindow is not supposed to be called because Dialog is initialized from a resource template.
Use InitDialog instead.
Regards,
Stas.
----------
From: Claus Michelsen
Sent: Wednesday, January 29, 1997 8:53 AM
To: mfc-l@netcom.com
Subject: CDialog::PreCreateWindow is never called
Environment: VC++ 4.2-flat, Win 95
I have created a CDialog-derived class with ClassWizard and have overriden
PreCreateWindow but it is never called. How is that?
I have tried to start the dialog box with both DoModal and Create.
Thanks!
Best regards,
Claus Michelsen
CRI A/S, Denmark
-----From: Pal_Sukhram/svoa0008@ssb.com
----------
>> From: owner-mfc-l; cmi
>> To: mfc-l
>> Subject: CDialog::PreCreateWindow is never called
>> Date: Wednesday, January 29, 1997 1:53AM
>> Environment: VC++ 4.2-flat, Win 95
>> I have created a CDialog-derived class with ClassWizard and have overriden
>> PreCreateWindow but it is never called. How is that?
Claus,
The function PreCreateWindow() is only get called for those windows
which are created by
MFC. If you are creating any control or dialog exists on the resource
template, then MFC
does not create it. In this case, MFC only creates the dialog template.
Windows will not call
PreCreateWindow () (Which is a MFC function of CWnd class) because
dialog is created by
Windows implicitly.
---To understand more clearly,
You can create a CEdit Box in a window using MFC Create function and
override the PreCreateWidnow () for this CEdit (CMyEdit, as an example)
class then it will get called. However, if you override PreCreateWindow
for any Edit control, which is defined in the dialog template resource,
this overriden function will not be called, by MFC. The reason for this is
already explained in the previous paragraph.
----
>> I have tried to start the dialog box with both DoModal and Create.
If you were doing this to change the dialog style, then either change
directly in the dialog resouce
template or use functions GetWindowStyle () & SetWindowStyle () to set
the proper style bits.
>> Thanks!
>> Best regards,
>> Claus Michelsen
>> CRI A/S, Denmark
Hope this will help you.
Thanks,
Sukhram
//--------------------------------------------------------------------
----------------------------------------
Sukhram Pal
Senior Systems Analyst,
State Street Bank & Trust Company,
P.O.Box. 1713,
Boston, MA 02105-1713
Tel. (617) 985.1348
EMail sukhram_pal@ssb.com
//--------------------------------------------------------------------
----------------------------------------
-----From: Roma
Claus Michelsen wrote:
>
> Environment: VC++ 4.2-flat, Win 95
>
> I have created a CDialog-derived class with ClassWizard and have overriden
> PreCreateWindow but it is never called. How is that?
>
> I have tried to start the dialog box with both DoModal and Create.
>
> Thanks!
>
PreCreateWindow(CREATESTRUCT &) is called from inside MFC code
(CWnd::Create, CWnd::CreateEx
and derived) to give you an opportunity to change some of the window
creation parameters.
In case of dialog creation you can (and you have to) change this stuff
in Resource
Editor. That's why CDialog::Create() doesn't call PreCreateWindow.
Here is a list of CREATESTRUCT members, which you can change in the
overriden PreCreateWindow,
and how you can do that for CDialog-derived class:
member Description
--------------------------------------------------------------------
lpCreateParams Points to data to be used for creating the window.
You can add some members to the derived class to pass initialization
data to youre dialog
hInstance Identifies the module that owns the new window.
I believe you don't want to change that.
hMenu Identifies the menu to be used by the new window.
Usually dialogs doesn't have menus
hwndParent obvious
You pass that to you CDialog constructor.
cy
cx
y
x
style Specifies the style for the new window.
lpszName Points to a null-terminated string that specifies the name of
the new window.
dwExStyle Specifies the extended style for the new window.
These parameters of the dialog could be changed in resource editor
lpszClass Points to a null-terminated string that specifies the class
name of the window.
This thing is fixed for the dialogs.
> Best regards,
> Claus Michelsen
> CRI A/S, Denmark
HTH
-Roma
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