MFC Snapping Windows

// SampleSnapperDlg.cpp : implementation file
//

#include "stdafx.h"
#include "SampleSnapper.h"
#include "SampleSnapperDlg.h"
#include "afxdialogex.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif


// CSampleSnapperDlg dialog




CSampleSnapperDlg::CSampleSnapperDlg(CWnd* pParent /*=NULL*/)
	: CExtPS < CDialogEx >(CSampleSnapperDlg::IDD, pParent)
{
	m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CSampleSnapperDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialogEx::DoDataExchange(pDX);
}

BEGIN_MESSAGE_MAP(CSampleSnapperDlg, CDialogEx)
	ON_WM_PAINT()
	ON_WM_QUERYDRAGICON()
	ON_BN_CLICKED(IDC_BUTTON1, &CSampleSnapperDlg::OnBnClickedButton1)
	ON_MESSAGE(WM_DESTROY_CHILD, CSampleSnapperDlg::OnDestroyChild)
END_MESSAGE_MAP()


// CSampleSnapperDlg message handlers

BOOL CSampleSnapperDlg::OnInitDialog()
{
	CDialogEx::OnInitDialog();

	// Set the icon for this dialog.  The framework does this automatically
	//  when the application's main window is not a dialog
	SetIcon(m_hIcon, TRUE);			// Set big icon
	SetIcon(m_hIcon, FALSE);		// Set small icon

	// TODO: Add extra initialization here

	return TRUE;  // return TRUE  unless you set the focus to a control
}

// If you add a minimize button to your dialog, you will need the code below
//  to draw the icon.  For MFC applications using the document/view model,
//  this is automatically done for you by the framework.

void CSampleSnapperDlg::OnPaint()
{
	if (IsIconic())
	{
		CPaintDC dc(this); // device context for painting

		SendMessage(WM_ICONERASEBKGND, reinterpret_cast<WPARAM>(dc.GetSafeHdc()), 0);

		// Center icon in client rectangle
		int cxIcon = GetSystemMetrics(SM_CXICON);
		int cyIcon = GetSystemMetrics(SM_CYICON);
		CRect rect;
		GetClientRect(&rect);
		int x = (rect.Width() - cxIcon + 1) / 2;
		int y = (rect.Height() - cyIcon + 1) / 2;

		// Draw the icon
		dc.DrawIcon(x, y, m_hIcon);
	}
	else
	{
		CDialogEx::OnPaint();
	}
}

// The system calls this function to obtain the cursor to display while the user drags
//  the minimized window.
HCURSOR CSampleSnapperDlg::OnQueryDragIcon()
{
	return static_cast<HCURSOR>(m_hIcon);
}

void CSampleSnapperDlg::OnBnClickedButton1()
{
	POSITION pos = m_Snappers.AddTail(new CChildSnapper());
	m_Snappers.GetAt(pos)->Create(CChildSnapper::IDD, this);
	m_Snappers.GetAt(pos)->ShowWindow(SW_SHOW);
	AddSnapper(m_Snappers.GetAt(pos)->GetSafeHwnd());
	//m_Snappers.GetAt(pos)->SetParentHwnd(GetSafeHwnd());

	// This is so we can delete the object and not leak memory
//	m_Snapper->SetParentHwnd(GetSafeHwnd());
	// TODO: Add your control notification handler code here
}

LRESULT CSampleSnapperDlg::OnDestroyChild(WPARAM wParam, LPARAM lParam)
{
	TRACE(_T("CSampleSnapperDlg::OnDestroyChild\n"));
	/*delete m_Snapper;*/
	CChildSnapper * ptrChild = NULL;
	HWND hWndChild = (HWND)wParam;

	POSITION pos = m_Snappers.GetHeadPosition();
	while (pos)
	{
		POSITION workingPOS = pos;
		ptrChild = m_Snappers.GetNext(pos);

		if ((ptrChild->GetSafeHwnd() == NULL) || 
			(ptrChild->GetSafeHwnd() == hWndChild))
		{
			m_Snappers.RemoveAt(workingPOS);
			delete ptrChild;
			return 0L;
		}
	}

	return 0L;
}

BOOL CSampleSnapperDlg::DestroyWindow()
{
	// TODO: Add your specialized code here and/or call the base class
	//while (!m_Snappers.IsEmpty())
	//	delete m_Snappers.RemoveHead();

	return CExtPS::DestroyWindow();
}