Q98598: HOWTO: Use CFormView in SDI and MDI Applications
Article: Q98598
Product(s): Microsoft C Compiler
Version(s): 1.0,1.5,1.51,1.52,2.0,2.1,5.0,6.0
Operating System(s):
Keyword(s): kbDocView kbMDI kbMFC KbUIDesign kbVC100 kbVC150 kbVC200 kbVC400 kbVC500 kbVC600 kbGrpD
Last Modified: 26-MAR-2002
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The information in this article applies to:
- The Microsoft Foundation Classes (MFC), used with:
- Microsoft Visual C++ for Windows, 16-bit edition, versions 1.0, 1.5, 1.51, 1.52
- Microsoft Visual C++, 32-bit Editions, versions 1.0, 2.0, 2.1, 5.0, 6.0
- Microsoft Visual C++.NET (2002)
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SUMMARY
=======
The CFormView class provides a convenient method to place controls into a view
that is based on a dialog box template. The general procedure to use a CFormView
is described in the documentation for the class and is illustrated in the VIEWEX
and CHKBOOK sample applications provided with Microsoft Foundation Classes (MFC)
versions 2.x and above. However, these applications do not demonstrate making
the initial size of the frame window to be the same as the initial size of the
form.
The following section lists the steps required to support creating a single
document interface (SDI) or multiple document interface (MDI) application based
on a CFormView, sizing the initial frame window around the form, changing the
style of the frame, and closing an MDI document using a button in the form.
MORE INFORMATION
================
The following steps describe how to create an MFC AppWizard application using
the CFormView as the default view:
1. Use the AppWizard to generate an SDI or MDI application.
2. Visual Studion 6.0:
At step 6 of the AppWizard, select the view class and specify CFormView as the
base class using the Base class combo box.
Visual Studio.NET:
In step 1 of the AppWizard, select Generated Classes and select CFormView as
the base class using the Base class combo box.
This inserts a dialog template with the proper styles set for your project's
resource file.
3. Override the OnUpdate() member function and call UpdateData() as documented
in the CFormView documentation to update the member variables with the
current document data and to perform dialog data exchange (DDX).
NOTE: UpdateData is not virtual and calling the base class ensures that the
derived class DoDataExchange is called through standard polymorphism. The
CFormView documentation states to call, not override UpdateData.
4. If you would like to set the initial size of the form view, override the
OnInitialUpdate() function. The text below provides additional information
about this step, which is slightly different in an SDI or MDI application.
Changing the Size of an SDI Main Frame Around a CFormView
---------------------------------------------------------
To change the size of the main frame of an SDI application (that uses CFormView
as its view class) to be the appropriate size for the form you designed in App
Studio, override the OnInitialUpdate() function in your class derived from
CFormView, as follows:
void CMyFormView::OnInitialUpdate()
{
CFormView::OnInitialUpdate();
GetParentFrame()->RecalcLayout();
ResizeParentToFit(); // default argument is TRUE
}
The ResizeParentToFit() function does not prevent the form from changing size
when the user changes the size of the application main frame (scroll bars are
added automatically if needed). To modify the style of the frame window that is
the parent of a form view, you can override the PreCreateWindow() function in
the CMainFrame class generated by AppWizard. For example, to remove the
WS_THICKFRAME style and prevent the user from changing the size of the window,
declare PreCreateWindow() in MAINFRM.H and add the following code to
MAINFRM.CPP:
BOOL CMainFrame::PreCreateWindow(CREATESTRUCT &cs)
{
cs.style &= ~WS_THICKFRAME;
return CFrameWnd::PreCreateWindow(cs);
}
Changing the Size of an MDI Child Frame Around a CFormView
----------------------------------------------------------
The process of changing the size of an MDI child frame is similar to changing the
size of a main frame for an SDI application, as explained above. However, the
RecalcLayout() call is not required.
To change the size of an MDI child frame around a form view, override the
OnInitialUpdate() function in your class derived from CFormView as follows:
void CMDIFormView::OnInitialUpdate()
{
CFormView::OnInitialUpdate();
ResizeParentToFit(); // Default argument is TRUE.
}
If the application overrides the default argument to the ResizeParentToFit()
function, essentially the same consequences occur as for an SDI application, as
explained above. In addition, the child window may be too large for the
enclosing MDI main frame or for the entire screen.
To change the style of the MDI child frame (for example, to remove the
WS_THICKFRAME style so the user cannot change the size of the window), derive an
MDI child window class and override the PreCreateWindow function as demonstrated
in the SDI example above.
Closing an MDI Form with a Button
---------------------------------
To create a button on a form that closes the document add a message handler for
the BN_CLICKED message to the CFormView class. Make sure that the buttons in
CFormView do not have the default IDOK or IDCANCEL identifiers. If they do, then
incorrect entries in the message map and incorrect functions for the buttons
will be created.
Once the message handler is in place, you can simulate the Close command on the
File menu with the following code:
void CMyForm::OnClickedButton1()
{
PostMessage(WM_COMMAND, ID_FILE_CLOSE);
}
This method to close a form prompts the user to save the file if the IsModified()
member function associated with the document returns TRUE.
Additional query words: kbfasttips
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Keywords : kbDocView kbMDI kbMFC KbUIDesign kbVC100 kbVC150 kbVC200 kbVC400 kbVC500 kbVC600 kbGrpDSMFCATL
Technology : kbAudDeveloper kbMFC
Version : :1.0,1.5,1.51,1.52,2.0,2.1,5.0,6.0
Issue type : kbhowto
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