CheckFrame Control

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Sometimes it can be handy to exclude a set of options based on
the users choice. For instance if the user do not want to save a
log file, then it should be signalled, to the user, which options
are relevant.

fig.1 The checkframe control are disabled, and so is its the
contained controls.

fig. 2 The check frame is enabled and the controls can be used.

The header file: CheckFrm.h

BOOL IsRectContainedInRect(CRect &rcChild, CRect &rcMother);

class CCheckFrame : public CObject
{
public:
	virtual void Enable(BOOL bEnable);
	void Set(CWnd *pParentWnd,UINT nFrmCtl);

	CWnd* m_pFrame;
	CWnd* m_pDialog;
	CRect m_rFrm;
	CDWordArray m_adwWndHandles;


protected:
};

The impementation file: CheckFrm.cpp
The code are futher commented in the source files.

#include "stdafx.h"
#include "Checkfrm.h"

//////////////////////////////////////
// EnumChildWnds Callback
BOOL CALLBACK EnumChildWnds(HWND hwnd, CCheckFrame *pObj)
{
	CRect R;
	GetWindowRect(hwnd, &R);
	pObj->m_pDialog->ScreenToClient(&R);

	if (hwnd != pObj->m_pFrame->m_hWnd)
	{
		if (IsRectContainedInRect(R, pObj->m_rFrm))
			pObj->m_adwWndHandles.Add((DWORD)hwnd);
	}

	return TRUE;
}


//////////////////////////////////////
// Function name	: Set
void CCheckFrame::Set(CWnd *pParentWnd, UINT nFrmCtl)
{
	m_pDialog = pParentWnd;

	// Calculate the size of the rect that should contain the controls
	m_pFrame = m_pDialog->GetDlgItem(nFrmCtl);
	if (!m_pFrame)
	{
		AfxMessageBox("Unable to find frame control");
		return;
	}
	m_pFrame->GetWindowRect(&m_rFrm);
	m_pDialog->ScreenToClient(&m_rFrm);

	// Make sure the array is empty
	m_adwWndHandles.RemoveAll();

	// The (control) windows contained within the boundaries of the frame control
	// are enumerated and their associated window-handles collected in an array.
	EnumChildWindows(m_pDialog->m_hWnd, (WNDENUMPROC)EnumChildWnds, (LONG)(CCheckFrame *)this);

}

//////////////////////////////////////
// Function name	: CCheckFrame::Enable
void CCheckFrame::Enable(BOOL bEnable)
{
	for (int i=0 ; i<m_adwWndHandles.GetSize() ; i++)
		EnableWindow((HWND)m_adwWndHandles[i], bEnable);
}

//////////////////////////////////////
// Function name	: IsRectContainedInRect
BOOL IsRectContainedInRect(CRect &rcChild, CRect &rcMother)
{
	if (rcMother.PtInRect(CPoint(rcChild.left, rcChild.top)) &&
	rcMother.PtInRect(CPoint(rcChild.left, rcChild.bottom)) &&
	rcMother.PtInRect(CPoint(rcChild.right, rcChild.top)) &&
	rcMother.PtInRect(CPoint(rcChild.right, rcChild.bottom)))
		return TRUE;

	return FALSE;
}

Known problems:
If the checkbox control it self is disabled when the progrma
exits, try to move it some pixels away from the border of the
frame control.

Download the sample project (31 kb)

Posted : March 12, 98