如何实现点一下对话框外面的区域,自动隐藏对话框

建立名为My的对话框程序.实现如下步骤:
在MyDlg.h中加入:

class CShowWindow1Dlg : public CDialog
{
public:
int m_cx;
int m_cy;
};

在MyDlg.cpp中:

//定义消息映象,处理鼠标单击及激活
BEGIN_MESSAGE_MAP(CMyDlg, CDialog)
ON_WM_LBUTTONDOWN()//添加
ON_WM_ACTIVATE()//添加
END_MESSAGE_MAP()

void CMyDlg::OnLButtonDown(UINT nFlags, CPoint point)
{
CRect rect;
GetClientRect(&rect);
rect.InflateRect(m_cx, m_cy);

//Release dialog if the user click outside it.
if(!rect.PtInRect(point))
{
EndDialog(IDCANCEL);
}

CDialog::OnLButtonDown(nFlags, point);
}

void CMyDlg::OnActivate(UINT nState, CWnd* pWndOther, BOOL bMinimized)
{
CDialog::OnActivate(nState, pWndOther, bMinimized);

if( nState == WA_ACTIVE || nState == WA_CLICKACTIVE)
SetCapture();
else
ReleaseCapture();
}

BOOL CMyDlg::OnInitDialog()
{
CDialog::OnInitDialog();
.....

OSVERSIONINFO info;
memset((char*)&info, 0, sizeof(OSVERSIONINFO));
info.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
if(GetVersionEx(&info))
{ //we don't run on Win32s, so check only two values
if(info.dwPlatformId == VER_PLATFORM_WIN32_WINDOWS)
{ //On windows 95
m_cx = GetSystemMetrics(SM_CXFIXEDFRAME);
m_cy = GetSystemMetrics(SM_CYFIXEDFRAME);
}
else
{ //On NT
m_cx = GetSystemMetrics(SM_CXDLGFRAME);
m_cy = GetSystemMetrics(SM_CYDLGFRAME);
}
}
}

说明:
1)WM_ACTIVATE消息在ClassWizard中没有,按如下步骤添加,右击CMyDlg类,选Add Windows Message Handle,接着在Filter for messages available to中选Window,在New Windows messages/events列表中就会出现WM_ACTIVATE,选中,点击Add Handler
2)SM_CXDLGFRAME,SM_CYDLGFRAME NT中取得有WS_DLGFRAMEstyle风格的窗口的高和宽 95中已经废弃而采用SM_CX_FIXEDFRAME和SM_CYFIXEDFRAME