如何将 CS_DROPSHADOW 应用于 CDialog 的子类

class CMyDialog : public CDialog
{
public:
    CMyDialog(CWnd* pParent = NULL)
        : CDialog(IDD_MYDIALOG, pParent)
    {
        Create(NULL, _T("My Dialog"));
        ModifyStyle(0, WS_POPUP | WS_VISIBLE);
        ModifyStyleEx(0, WS_EX_TOPMOST | WS_EX_TOOLWINDOW);
        ModifyStyleEx(0, WS_EX_LAYERED | WS_EX_TRANSPARENT);
        SetLayeredWindowAttributes(0, 255, LWA_ALPHA);
        SetWindowPos(&wndTopMost, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_SHOWWINDOW);
    }

    // ...

    afx_msg void OnPaint();
    afx_msg void OnNcPaint();
    afx_msg BOOL OnNcActivate(BOOL bActive);
    afx_msg LRESULT OnNcCalcSize(WPARAM wParam, LPARAM lParam);
    afx_msg LRESULT OnNcHitTest(CPoint point);
    afx_msg void OnNcMouseMove(UINT nHitTest, CPoint point);
    afx_msg void OnNcLButtonDown(UINT nHitTest, CPoint point);
    afx_msg void OnNcLButtonUp(UINT nHitTest, CPoint point);
    afx_msg void OnNcRButtonDown(UINT nHitTest, CPoint point);
    afx_msg void OnNcRButtonUp(UINT nHitTest, CPoint point);

    DECLARE_MESSAGE_MAP()
};

BEGIN_MESSAGE_MAP(CMyDialog, CDialog)
    ON_WM_PAINT()
    ON_WM_NCPAINT()
    ON_WM_NCACTIVATE()
    ON_WM_NCCALCSIZE()
    ON_WM_NCHITTEST()
    ON_WM_NCMOUSEMOVE()
    ON_WM_NCLBUTTONDOWN()
    ON_WM_NCLBUTTONUP()
    ON_WM_NCRBUTTONDOWN()
    ON_WM_NCRBUTTONUP()
END_MESSAGE_MAP()

void CMyDialog::OnPaint()
{
    CPaintDC dc(this);
    CRect rect;
    GetClientRect(rect);
    dc.FillSolidRect(rect, RGB(255, 255, 255));
}

void CMyDialog::OnNcPaint()
{
    CWindowDC dc(this);
    CRect rect;
    GetWindowRect(rect);
    rect.OffsetRect(-rect.left, -rect.top);
    dc.DrawEdge(rect, EDGE_RAISED, BF_RECT);
}

BOOL CMyDialog::OnNcActivate(BOOL bActive)
{
    return TRUE;
}

LRESULT CMyDialog::OnNcCalcSize(WPARAM wParam, LPARAM lParam)
{
    return 0;
}

LRESULT CMyDialog::OnNcHitTest(CPoint point)
{
    return HTCLIENT;
}

void CMyDialog::OnNcMouseMove(UINT nHitTest, CPoint point)
{
}

void CMyDialog::OnNcLButtonDown(UINT nHitTest, CPoint point)
{
}

void CMyDialog::OnNcLButtonUp(UINT nHitTest, CPoint point)
{
}

void CMyDialog::OnNcRButtonDown(UINT nHitTest, CPoint point)
{
}

void CMyDialog::OnNcRButtonUp(UINT nHitTest, CPoint point)
{
}