透明窗口

    最近做了一个透明窗口，实现这样的功能：一个窗体完全透明，上面有几个图标，每个图标可以点击，但是透明窗体必须挡住后面的窗体，即禁止后面的窗体激活。此时必须使用两个窗体实现，一个为主窗体(TransparencyDlg)，100%透明(采用LWA_COLORKEY过滤白色)，上面有图标。另外一个窗体(CoverDlg)盖在它上面，99%透明(采用LWA_ALPHA实现)，防止背后窗体激活。核心代码如下：

BOOL CTransparencyDlg::OnInitDialog()
{
CDialog::OnInitDialog();
// 设置此对话框的图标。当应用程序主窗口不是对话框时，框架将自动
//  执行此操作
SetIcon(m_hIcon, TRUE);   // 设置大图标
SetIcon(m_hIcon, FALSE);  // 设置小图标
// TODO: 在此添加额外的初始化代码
CCoverDlg *pDlg = new CCoverDlg();
pDlg->m_hTargetWnd = GetSafeHwnd();
pDlg->Create(IDD_DLGCOVER);
pDlg->ShowWindow(SW_SHOW);

HWND hWnd = GetSafeHwnd();
::SetWindowLong(hWnd, GWL_EXSTYLE, ::GetWindowLong(hWnd, GWL_EXSTYLE)|WS_EX_LAYERED|WS_EX_TOOLWINDOW);
::SetLayeredWindowAttributes(hWnd, RGB(255,255,255), 0, LWA_COLORKEY);

return TRUE;  // 除非将焦点设置到控件，否则返回 TRUE
}

void CTransparencyDlg::OnPaint()
{
if (！IsIconic())
{
  CDialog::OnPaint();

  RECT rect;
  ::GetWindowRect(::GetDesktopWindow(), &rect);
  ::MoveWindow(GetSafeHwnd(), 0, 0, rect.right-rect.left
   , (UINT32)((rect.bottom-rect.top)*0.04), TRUE);
}
}

HBRUSH CTransparencyDlg::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor)
{
HBRUSH hbr = CDialog::OnCtlColor(pDC, pWnd, nCtlColor);
// TODO:  在此更改 DC 的任何属性
if (nCtlColor==CTLCOLOR_DLG || nCtlColor==CTLCOLOR_STATIC)
{
  return CreateSolidBrush(RGB(255, 255, 255));
}

// TODO:  如果默认的不是所需画笔，则返回另一个画笔
return hbr;
}

void CTransparencyDlg::OnLButtonDown(UINT nFlags, CPoint point)
{
// TODO: 在此添加消息处理程序代码和/或调用默认值
TRACE2("CTransparencyDlg::OnLButtonDown(%d,%d)/r/n", point.x, point.y);

RECT rect;
HWND hFather = GetSafeHwnd();
HWND hNextChild = ::GetWindow(hFather, GW_CHILD);
while (::IsWindow(hNextChild))
{
  if (::GetParent(hNextChild) == hFather
   && (::GetWindowLong(hNextChild, GWL_STYLE)&WS_VISIBLE) != NULL)  //子窗体有效且可见
  {
   ::GetWindowRect(hNextChild, &rect);
   if(::PtInRect(&rect, point))
   {
    ::SendMessage(hNextChild, WM_LBUTTONDOWN, (WPARAM)nFlags, MAKELPARAM(point.x, point.y));
    break;
   }
  }
  hNextChild = ::GetWindow(hNextChild, GW_HWNDNEXT);
}

CDialog::OnLButtonDown(nFlags, point);
}

void CTransparencyDlg::OnStnClickedPicture()
{
// TODO: 在此添加控件通知处理程序代码
TRACE("CTransparencyDlg::OnStnClickedPicture/r/n");
}

BOOL CCoverDlg::OnInitDialog()
{
CDialog::OnInitDialog();

// TODO: 在此添加额外的初始化代码
HWND hWnd = GetSafeHwnd();
::SetWindowLong(hWnd, GWL_EXSTYLE, ::GetWindowLong(hWnd, GWL_EXSTYLE)|WS_EX_LAYERED|WS_EX_TOOLWINDOW);
::SetLayeredWindowAttributes(hWnd, 0, 1, LWA_ALPHA);

return TRUE;  // return TRUE unless you set the focus to a control
// 异常: OCX 属性页应返回 FALSE
}

void CCoverDlg::OnPaint()
{
if (!IsIconic())
{
  CDialog::OnPaint();

  RECT rect;
  ::GetWindowRect(::GetDesktopWindow(), &rect);
  ::MoveWindow(GetSafeHwnd(), 0, 0, rect.right-rect.left
   , (UINT32)((rect.bottom-rect.top)*0.04), TRUE);
}
}

void CCoverDlg::OnLButtonDown(UINT nFlags, CPoint point)
{
// TODO: 在此添加消息处理程序代码和/或调用默认值
TRACE2("CCoverDlg::OnLButtonDown(%d,%d)/r/n", point.x, point.y);
::SendMessage(m_hTargetWnd, WM_LBUTTONDOWN, (WPARAM)nFlags, MAKELPARAM(point.x, point.y));

CDialog::OnLButtonDown(nFlags, point);
}