HOWTO: Make a Resizable Dialog Bar
ID: Q143255
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The information in this article applies to:
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The Microsoft Foundation Classes (MFC), included with:
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Microsoft Visual C++, 32-bit Editions, versions 2.0, 2.1, 2.2, 4.0, 5.0, 6.0
SUMMARY
The default MFC implementation of CDialogBar does not allow for the dialog
bar to be resizable when it is floating. If the dialog bar contains
controls that are sensibly resized, the programmer may want to make the
dialog bar resizable by using the techique described in this article.
To make the dialog bar resizable when using versions of MFC earlier than
version 4.0:
- Change the style of the mini frame window enclosing the floating dialog
bar so that it is resizable.
- Override CDialogBar to provide a CalcFixedLayout, which allows the
dialog bar and its controls to be resized.
To make the dialog bar resizable when using MFC version 4.0 or later, you
can use the built-in support for resizable control bars. However, dialog
bars do not get this behavior by default. To make a dialog bar resizable:
- Use the new CBRS_SIZE_DYNAMIC style when creating the dialog bar.
- Add code to an override of the new CalcDynamicLayout() function.
MORE INFORMATIONFor versions of MFC Earlier Than Version 4.0
CDialogBar contains an embedded member variable m_sizeDefault of type
CSize. On creation, m_sizeDefault is set to the size of the dialog template
embedded in the dialog bar. Whenever the dialog bar is resized or
repositioned, MFC calls CDialogBar::CalcFixedLayout(). This member function
is intended to return the appropriate size of the control bar; for
CDialogBar, CalcFixedLayout() usually returns m_sizeDefault. This causes
the dialog bar to always snap back to its default size.
To create a resizable dialog bar, you must ensure that the following things
are handled in some manner by an application:
- The CMiniDockFrameWnd surrounding the floating dialog bar must have its
window styles changed so that it is resizable.
- A member variable must be added to a class derived from CDialogBar to
represent the appropriate floating size.
- CalcFixedLayout() must be overridden in this class to set and return the
floating size of the dialog bar when the dialog bar is being resized.
With the appropriate tests, both 1 and 3 can be implemented in
CalcFixedLayout(). See the "Sample Code" section of this article for an
example of this.
For MFC Version 4.0 and Later
In MFC 4.0 and higher, control bars support the new CBRS_SIZE_DYNAMIC
style. CBRS_SIZE_DYNAMIC allows a floating control bar to be dynamically
resized when the user drags the control bar's border. The virtual function
CControlBar::CalcDynamicLayout() has been added to determine the size that
a control bar should be resized to.
CalcDynamicLayout() is called for CBRS_SIZE_DYNAMIC control bars when the
border of a floating control bar is dragged and when the control bar is
docked or floated. The default CControlBar implementation simply calls
CalcFixedLayout(), which prevents control bar objects from resizing unless
CalcDynamicLayout() is overridden. CDialogBar does not override
CalcDynamicLayout(), so by default, dialog bars are not resizable.
Therefore, to make a resizable dialog bar using MFC 4.0:
- Create a new class derived from CDialogBar and override the
CalcDynamicLayout() function. Depending on the behavior you want,
it may be necessary to add a member variable to the class.
- Create an instance of this class using the CBRS_SIZE_DYNAMIC style bit.
Dialog bars are typically created in CMainFrame::OnCreate():
if (!m_wndDialogBar.Create(this, IDD_DIALOGBAR,
CBRS_TOP | CBRS_SIZE_DYNAMIC, 777))
{
TRACE0("Failed to create dialogbar\n");
return -1;
}
m_wndDialogBar.EnableDocking(CBRS_ALIGN_ANY);
DockControlBar(&m_wndDialogBar);
See the "Sample Code" section in this article for a examples of this.
SAMPLE CODE
Sample Code for MFC versions Prior to Visual C++ 4.0
/* Compile options needed: Default
*/
// RSZDLGBR.H : header file
//
class CResizableDlgBar : public CDialogBar
{
// Construction
public:
BOOL Create( CWnd* pParentWnd, UINT nIDTemplate, UINT nStyle,
UINT nID, BOOL = TRUE);
BOOL Create( CWnd* pParentWnd, LPCTSTR lpszTemplateName,
UINT nStyle, UINT nID, BOOL = TRUE);
// Attributes
public:
CSize m_sizeDocked;
CSize m_sizeFloating;
BOOL m_bChangeDockedSize; // Indicates whether to keep
// a default size for docking
// Operations
public:
// Overrides
virtual CSize CalcFixedLayout(BOOL bStretch, BOOL bHorz);
// Implementation
public:
};
/////////////////////////////////////////////////////////////////////
// RSZDLGBR.CPP : implementation file
//
#include "stdafx.h"
#include <afxpriv.h>
#include "ResizableDlgBar.h"
#include "resource.h"
////////////////////////////////////////////////////////////////////
// CResizableDlgBar Construction/Destruction
BOOL CResizableDlgBar::Create( CWnd* pParentWnd, UINT nIDTemplate,
UINT nStyle, UINT nID, BOOL bChange)
{
if(!CDialogBar::Create(pParentWnd,nIDTemplate,nStyle,nID))
return FALSE;
m_bChangeDockedSize = bChange;
m_sizeFloating = m_sizeDocked = m_sizeDefault;
return TRUE;
}
BOOL CResizableDlgBar::Create( CWnd* pParentWnd,
LPCTSTR lpszTemplateName,
UINT nStyle, UINT nID, BOOL bChange)
{
if (!CDialogBar::Create( pParentWnd, lpszTemplateName,
nStyle, nID))
return FALSE;
m_bChangeDockedSize = bChange;
m_sizeFloating = m_sizeDocked = m_sizeDefault;
return TRUE;
}
////////////////////////////////////////////////////////////////////
// Overloaded functions
CSize CResizableDlgBar::CalcFixedLayout(BOOL bStretch, BOOL bHorz)
{
if (IsFloating())
{
// Get the parent mini frame wnd
CMiniDockFrameWnd* pFrame =
((CMiniDockFrameWnd*)m_pDockBar->GetParent());
CRect rcFrame;
pFrame->GetClientRect(&rcFrame);
// Is its size (0,0)? If so, it was just floated
CSize sizerc(rcFrame.right - rcFrame.left,
rcFrame.bottom - rcFrame.top);
if (!((sizerc.cx <= 0) && (sizerc.cy <= 0)))
return ((m_bChangeDockedSize) ?
m_sizeDocked = m_sizeFloating = sizerc :
m_sizeFloating = sizerc);
else
{
// Modify Style when dialog bar is first floated
pFrame->ModifyStyle(MFS_MOVEFRAME, WS_THICKFRAME, 0);
m_dwStyle |= MFS_THICKFRAME;
m_dwStyle |= WS_THICKFRAME;
m_dwStyle &= ~MFS_MOVEFRAME;
// Return last floated size
return m_sizeFloating;
}
}
if (bStretch) // if not docked stretch to fit
return CSize(bHorz ? 32767 : m_sizeDocked.cx,
bHorz ? m_sizeDocked.cy : 32767);
else
return m_sizeDocked;
}
Sample Code for MFC Included with Visual C++ 4.0 and above
/* Compile options needed: Default
*/
// ResizableDlgBar.h : header file
//
class CResizableDlgBar : public CDialogBar
{
// Construction
public:
BOOL Create( CWnd* pParentWnd, UINT nIDTemplate, UINT nStyle,
UINT nID, BOOL = TRUE);
BOOL Create( CWnd* pParentWnd, LPCTSTR lpszTemplateName,
UINT nStyle, UINT nID, BOOL = TRUE);
// Attributes
public:
CSize m_sizeDocked;
CSize m_sizeFloating;
BOOL m_bChangeDockedSize; // Indicates whether to keep
// a default size for docking
// Operations
public:
// Overrides
// ClassWizard generated virtual function overrides
//{{AFX_VIRTUAL(CResizableDlgBar)
//}}AFX_VIRTUAL
virtual CSize CalcDynamicLayout( int nLength, DWORD dwMode );
// Implementation
public:
// Generated message map functions
protected:
//{{AFX_MSG(CResizableDlgBar)
// NOTE - the ClassWizard will add and remove member functions here.
//}}AFX_MSG
DECLARE_MESSAGE_MAP()
};
/////////////////////////////////////////////////////////////////////
// ResizableDlgBar.cpp : implementation file
//
#include "stdafx.h"
#include "ResizableDlgBar.h"
////////////////////////////////////////////////////////////////////
// CResizableDlgBar Construction/Destruction
BOOL CResizableDlgBar::Create( CWnd* pParentWnd, UINT nIDTemplate,
UINT nStyle, UINT nID, BOOL bChange)
{
if(!CDialogBar::Create(pParentWnd,nIDTemplate,nStyle,nID))
return FALSE;
m_bChangeDockedSize = bChange;
m_sizeFloating = m_sizeDocked = m_sizeDefault;
return TRUE;
}
BOOL CResizableDlgBar::Create( CWnd* pParentWnd,
LPCTSTR lpszTemplateName, UINT nStyle,
UINT nID, BOOL bChange)
{
if (!CDialogBar::Create( pParentWnd, lpszTemplateName,
nStyle, nID))
return FALSE;
m_bChangeDockedSize = bChange;
m_sizeFloating = m_sizeDocked = m_sizeDefault;
return TRUE;
}
////////////////////////////////////////////////////////////////////
// Overloaded functions
CSize CResizableDlgBar::CalcDynamicLayout(int nLength, DWORD dwMode)
{
// Return default if it is being docked or floated
if ((dwMode & LM_VERTDOCK) || (dwMode & LM_HORZDOCK))
{
if (dwMode & LM_STRETCH) // if not docked stretch to fit
return CSize((dwMode & LM_HORZ) ? 32767 : m_sizeDocked.cx,
(dwMode & LM_HORZ) ? m_sizeDocked.cy : 32767);
else
return m_sizeDocked;
}
if (dwMode & LM_MRUWIDTH)
return m_sizeFloating;
// In all other cases, accept the dynamic length
if (dwMode & LM_LENGTHY)
return CSize(m_sizeFloating.cx, (m_bChangeDockedSize) ?
m_sizeFloating.cy = m_sizeDocked.cy = nLength :
m_sizeFloating.cy = nLength);
else
return CSize((m_bChangeDockedSize) ?
m_sizeFloating.cx = m_sizeDocked.cx = nLength :
m_sizeFloating.cx = nLength, m_sizeFloating.cy);
}
BEGIN_MESSAGE_MAP(CResizableDlgBar, CDialogBar)
//{{AFX_MSG_MAP(CResizableDlgBar)
// NOTE - the ClassWizard will add and remove mapping macros
here.
//}}AFX_MSG_MAP
END_MESSAGE_MAP()
/////////////////////////////////////////////////////////////////////
// CResizableDlgBar message handlers
/////////////////////////////////////////////////////////////////////
REFERENCES
MFC Technical Note 31.
© Microsoft Corporation 1999, All Rights Reserved.
Contributions by Jason Strayer, Microsoft Corporation
Keywords : kbcode kbMFC KbUIDesign kbVC kbVC200 kbVC210 kbVC220 kbVC400 kbVC500 kbVC600 kbfaq
Version : 2.0 2.1 2.2 4.0 5.0 6.0
Platform : NT WINDOWS
Issue type : kbhowto
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