CResizableDialog - What is it & Why?
I wrote my own class to implement resizable dialogs mostly as an exercise of
MFC and Windows programming. Later, I discovered that other people had written
similar classes, but I didn't find one I really like that was as simple as my
Before you go any further, I have to warn you that I'm not a
"guru". Surely something could be done better, but I think this class
is at least easy to use.
The user will have the ability to resize the dialog, with consequent
rearrangement of child windows, and you can control the minimum and maximum
size allowed, as well as the maximized size and position of the dialog. The
size grip is displayed by default, but you may turn it off. Automatic Save/Restore
the dialog's size and position is also supported.
Conversion of a previously existant dialog should be very simple, as well as
creation of a new resizable dialog.
Now implemented with ResizableLib (see article).
The Sample Application
This is a view of the sample dialogs:
This is a composite view, where you can see the maximized position is not
You may see how to do this in the next section.
Usage - Step by Step
Add the ResizableLib to your project's workspace, as explained in the
Create a dialog resource and associate it with a
derived class, for example using Class Wizard, or take a dialog you have
already made which you want to be resizable.
You no longer need to change the window style to have the dialog resizing.
Include 'ResizableDialog.h' in the associated header file.
Search and replace all
CDialog occurrences with
in both your .cpp and .h files, just as if your dialog class was derived from
CDialog. I think there's no way to let the Class Wizard
do this for you. Let me know if I'm wrong, please.
Your header file should appear like this:
class CMyDialog : public CResizableDialog
CMyDialog(CWnd* pParent = NULL);
OnInitDialog override, add an anchor for each control
you want the size and/or position to be changed when the user resizes the
AddAnchor(IDC_EDIT1, TOP_LEFT, BOTTOM_RIGHT);
AddAnchor(IDC_GROUP1, BOTTOM_LEFT, BOTTOM_RIGHT);
Here you may also set a maximum size for your dialog (default is the
workspace area), a minimum size (default is the one you set in the resource
editor) and also a rectangle that the dialog occupies when maximized.
rc.bottom = 100;
After all this settings, you may wish the dialog's size and position to be
automatically saved and restored, as well as its maximized or minimized state.
Just provide a Section and an Entry name in your application's profile, in
which to save dialog's status.
You are ready to rebuild your project and you will have a resizable dialog
just as you wanted.
For further details, see the next section.
This class inherits from
CResizableState, and obviously from
CResizableDialog(UINT nIDTemplate, CWnd* pParentWnd = NULL)
CResizableDialog(LPCTSTR lpszTemplateName, CWnd* pParentWnd = NULL)
The first is the default constructor.
The second and the third forms are needed to reproduce the construction scheme of a
CDialog derived class. Since the
dialog resource template is needed by the
CDialog constructor, you have to call one of these forms of the
constructor. This is the reason why replacing one class with the other will work.
void EnableSaveRestore(LPCTSTR pszSection, BOOL bRectOnly = FALSE)
Enables automatic save/restore on dialog's open/close operations. The
arguments are the same as in
TRUE, the minimized/maximized
state is not saved/restored. Should be called after all the layout
If you want details on how this information is stored by your
application, look at
CWinApp::m_pszRegistryKey on MFC documentation.
Implemented in the various base classes, see ResizableLib article.
I would like to make this class more "integrated" with Class
Wizard, but I don't even know if it's possible. I hope this class can be useful
to other programmers that just want to have resizable dialogs with the minimum
I implemented a sort of percentage resizing. However, currently available
anchor types do not permit a high level of complexity, but should be enough in
many applications. If you want more flexibility or if your dialogs are very big
and full of controls, you may search CodeProject for another solution in this
same Section (see the top of the article).
The CVS tree is now on Source
25 May 2000
31 May 2000
- Some unneeded code has been removed.
- Flickering has been reduced for Button, Static and ListBox controls.
- Save/Restore support has been added.
- Fixed a nasty bug that only came out with modeless dialogs.
9 Jun 2000
- Now compiles cleanly at warning level 4.
- Memory leak fixed. (I completely forgot to free memory)
- New type of anchorage now allowing more complex layouts. (compatible
with previous code)
- Fixed a bug with the size grip when hidden and when the dialog is
- Better handling of controls that need repainting.
- Demo project updated to show new features.
11 Jul 2000
- Fixed a minor bug in save/restore functions. (standard maximized dialog
wasn't restored correctly)
27 Oct 2000
- Changed layout implementation (from
- Fixed a bug with controls that need refresh
23 Nov 2000
- Fixed a bug with multiple calls to
- Removed doc from zip files (you simply save this page if you need it)
13 Mar 2001
- Fixed a bug with radio buttons and group boxes (thanks to Matt Philmon)
- Changed copyright note
11 Jun 2001
- New implementation and integration with ResizableLib
- Automatic resizing style (thanks to John Simmons)
- Added anti-flickering support
15 Jul 2001
- Updated to new ResizableLib release
- Demo project shows new grip implementation
28 Oct 2001
- Version 1.1 (CVS Tag: SF_1_1)
- Added static build configurations to all projects