How to implement mouse hover/leave message on system tray.

// TrayPosDemoDlg.cpp : implementation file
//

#include "stdafx.h"
#include "TrayPosDemo.h"
#include "TrayPosDemoDlg.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CTrayPosDemoDlg dialog

CTrayPosDemoDlg::CTrayPosDemoDlg(CWnd* pParent /*=NULL*/)
	: CDialog(CTrayPosDemoDlg::IDD, pParent)
{
	//{{AFX_DATA_INIT(CTrayPosDemoDlg)
		// NOTE: the ClassWizard will add member initialization here
	//}}AFX_DATA_INIT
	// Note that LoadIcon does not require a subsequent DestroyIcon in Win32
	m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CTrayPosDemoDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(CTrayPosDemoDlg)
		// NOTE: the ClassWizard will add DDX and DDV calls here
	//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CTrayPosDemoDlg, CDialog)
	//{{AFX_MSG_MAP(CTrayPosDemoDlg)
	ON_WM_PAINT()
	ON_WM_QUERYDRAGICON()
	ON_WM_DESTROY()
	//}}AFX_MSG_MAP
	ON_MESSAGE(WM_TRAYNOTIFY, OnTrayNotify)
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CTrayPosDemoDlg message handlers

BOOL CTrayPosDemoDlg::OnInitDialog()
{
	CDialog::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
	NOTIFYICONDATA	nid;

	nid.cbSize = sizeof nid;
	nid.hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
	nid.hWnd = m_hWnd;
	nid.uCallbackMessage = WM_TRAYNOTIFY;
	nid.uID = 1;
	nid.uFlags = NIF_ICON | NIF_MESSAGE;

	Shell_NotifyIcon(NIM_ADD, &nid);
	m_traypos.SetNotifyIconInfo(m_hWnd, 1, WM_TRAYNOTIFY);
	
	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 CTrayPosDemoDlg::OnPaint() 
{
	if (IsIconic())
	{
		CPaintDC dc(this); // device context for painting

		SendMessage(WM_ICONERASEBKGND, (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
	{
		CDialog::OnPaint();
	}
}

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

LONG CTrayPosDemoDlg::OnTrayNotify(WPARAM wParam, LPARAM lParam)
{
	if(wParam == 1)
	{
		switch(lParam)
		{
		case WM_MOUSEMOVE:
			m_traypos.OnMouseMove();
			break;

		case WM_MOUSEHOVER:
			m_dlg.Create(CBmpDlg::IDD, this);
			m_dlg.ShowWindow(SW_SHOW);
			break;

		case WM_MOUSELEAVE:
			m_dlg.ShowWindow(SW_HIDE);
			m_dlg.DestroyWindow();
			break;
		}
	}
	return 0;
}

void CTrayPosDemoDlg::OnDestroy() 
{
	CDialog::OnDestroy();
	
	// TODO: Add your message handler code here
	NOTIFYICONDATA	nid;
	
	nid.cbSize = sizeof nid;
	nid.hWnd = m_hWnd;
	nid.uID = 1;
	nid.uFlags = 0;
	
	Shell_NotifyIcon(NIM_DELETE, &nid);
}