新旧MFC版本实现CEdit透明的2种方法的实例代码

HBRUSH CAlphaEditboxDlg::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor) 
{
    HBRUSH hbr = CDialog::OnCtlColor(pDC, pWnd, nCtlColor);

    // TODO: Change any attributes of the DC here
    pDC->SetBkMode(TRANSPARENT);
    hbr=(HBRUSH)GetStockObject(HOLLOW_BRUSH);
    // TODO: Return a different brush if the default is not desired
    return hbr;
}

void CAlphaEditboxDlg::OnKillfocusEditkey() 
{
    // TODO: Add your control notification handler code here
    Invalidate();
}

void CAlphaEditboxDlg::OnKillfocusEditmessage() 
{
    // TODO: Add your control notification handler code here
    Invalidate();
}

void CAlphaEditboxDlg::OnKillfocusEditpath() 
{
    // TODO: Add your control notification handler code here
    Invalidate();
}

//////////////////////////////////////////////////////////////////////////
//绘制窗口。
//////////////////////////////////////////////////////////////////////////
void CMyEdit::OnPaint()
{
    PAINTSTRUCT ps;
    TEXTMETRIC tm;
    int nSelStart=0,nSelEnd=0,nDrawStart=0,nDrawLen=0,nTxtLen=0;
    RECT r;
    CBitmap b;
    LPTSTR sz=(LPTSTR)calloc(1024,sizeof(TCHAR));
    CPaintDC* d2=(CPaintDC*)BeginPaint(&ps);
    CDC d1;
    CFont f;
    CWnd* p=GetParent();
    nTxtLen=GetWindowText(sz,1024);
    b.LoadBitmap(IDB_BITMAP1);
    d1.CreateCompatibleDC(p->GetDC());
    GetWindowRect(&r);
    p->ScreenToClient(&r);
    d1.SelectObject(b);
    d2->BitBlt(0,0,r.right-r.left,r.bottom-r.top,&d1,r.left,r.top,SRCCOPY);
    f.CreateFontIndirect(&m_lf);
    d2->SelectObject(f);
    d2->SetBkMode(TRANSPARENT);
    d2->GetTextMetrics(&tm);
    GetSel(nSelStart,nSelEnd);
    if (r.right-r.left<nTxtLen*tm.tmAveCharWidth)
    {
        nDrawStart=0-tm.tmAveCharWidth*nSelStart;
        nDrawLen=(r.right-r.left)/tm.tmAveCharWidth;
    }
    else
    {
        nDrawStart=0;
        nDrawLen=nTxtLen;
    }
    d2->TextOut(nDrawStart,3,sz,nDrawLen);
    d2->SelectObject(GetStockObject(NULL_BRUSH));
    d2->SelectObject(CreatePen(PS_DOT,1,RGB(255,0,0)));
    d2->Rectangle(0,0,r.right-r.left,r.bottom-r.top);
    POINT pt;
    pt=GetCaretPos();
    pt.x=nDrawLen*tm.tmAveCharWidth;
    SetCaretPos(pt);
    delete sz;
    EndPaint(&ps);
}

//////////////////////////////////////////////////////////////////////////
//暂不处理粘滞按键和功能键这2种情况。
//////////////////////////////////////////////////////////////////////////
void CMyEdit::OnChar(UINT nChar, UINT nRepCnt, UINT nFlags)
{
    TEXTMETRIC tm;
    int nSelStart=0,nSelEnd=0,nDrawStart=0,nDrawLen=0,nTxtLen=0;
    RECT r;
    CBitmap b;
    LPTSTR sz=(LPTSTR)calloc(1024,sizeof(TCHAR));
    LPTSTR input=(LPTSTR)calloc(1024,sizeof(TCHAR));
    CClientDC d2(this);
    CDC d1;
    CFont f;
    CWnd* p=GetParent();
    nTxtLen=GetWindowText(sz,1024);
    wsprintf(input,L"%c",nChar);
    lstrcat(sz,input);
    SetWindowText(sz);
    b.LoadBitmap(IDB_BITMAP1);
    d1.CreateCompatibleDC(p->GetDC());
    GetWindowRect(&r);
    p->ScreenToClient(&r);
    d1.SelectObject(b);
    d2.BitBlt(0,0,r.right-r.left,r.bottom-r.top,&d1,r.left,r.top,SRCCOPY);
    f.CreateFontIndirect(&m_lf);
    d2.SelectObject(f);
    d2.SetBkMode(TRANSPARENT);
    d2.GetTextMetrics(&tm);
    GetSel(nSelStart,nSelEnd);
    if (r.right-r.left<nTxtLen*tm.tmAveCharWidth)
    {
        nDrawStart=0-tm.tmAveCharWidth*nSelStart;
        nDrawLen=(r.right-r.left)/tm.tmAveCharWidth;
    }
    else
    {
        nDrawStart=0;
        nDrawLen=nTxtLen;
    }
    d2.TextOut(nDrawStart,3,sz,nDrawLen);
    d2.SelectObject(GetStockObject(NULL_BRUSH));
    d2.SelectObject(CreatePen(PS_DOT,1,RGB(255,0,0)));
    d2.Rectangle(0,0,r.right-r.left,r.bottom-r.top);
    POINT pt;
    pt=GetCaretPos();
    pt.x=nDrawLen*tm.tmAveCharWidth;
    SetCaretPos(pt);
    delete sz;
    delete input;
    //CEdit::OnChar(nChar, nRepCnt, nFlags);
}