3.拉伸視窗

新增WM_NCHITTEST和WM_NCLBUTTONDOWN

我們先新增一個變數，是否可以拉伸，預設初始化為true即可，畢竟視窗拉伸是視窗基本的屬性之一

bool                        m_bExtrude;         //是否可以拉伸

LRESULT CDialogEx::OnNcHitTest(CPoint point)
{
    if( m_bExtrude )
    {
        CRect rcWindow;
        GetWindowRect(&rcWindow);
   
        if ((point.x <= rcWindow.left+BORDERWIDTH) && (point.y>BORDERWIDTH) && (point.y<rcWindow.bottom-BORDERWIDTH*2) )
            return HTLEFT;
        else if ((point.x >= rcWindow.right-BORDERWIDTH) && (point.y>BORDERWIDTH) && (point.y<rcWindow.bottom-BORDERWIDTH*2) )
            return HTRIGHT;
        else if ((point.y <= rcWindow.top+BORDERWIDTH) && (point.x>BORDERWIDTH) && (point.x<rcWindow.right-BORDERWIDTH*2))
            return HTTOP;
        else if ((point.y >= rcWindow.bottom-BORDERWIDTH) && (point.x>BORDERWIDTH) && (point.x<rcWindow.right-BORDERWIDTH*2))
            return HTBOTTOM;
        else if ((point.x <= rcWindow.left+BORDERWIDTH*2) && (point.y <= rcWindow.top+BORDERWIDTH*2))
            return HTTOPLEFT;
        else if ((point.x >= rcWindow.right-BORDERWIDTH*2) && (point.y <= rcWindow.top+BORDERWIDTH*2))
            return HTTOPRIGHT;
        else if ((point.x <= rcWindow.left+BORDERWIDTH*2) && (point.y >= rcWindow.bottom-BORDERWIDTH*2))
            return HTBOTTOMLEFT;
        else if ((point.x >= rcWindow.right-BORDERWIDTH*2) && (point.y >= rcWindow.bottom-BORDERWIDTH*2))
            return HTBOTTOMRIGHT;
        else
            return CWnd::OnNcHitTest(point);
   
        return 0;
    }
    else
        return CDialog::OnNcHitTest(point);
}
   
void CDialogEx::OnNcLButtonDown(UINT nHitTest, CPoint point)
{
    if( m_bExtrude )
    {
        if (nHitTest == HTTOP)      
            SendMessage( WM_SYSCOMMAND, SC_SIZE | WMSZ_TOP, MAKELPARAM(point.x, point.y));
        else if (nHitTest == HTBOTTOM)
            SendMessage( WM_SYSCOMMAND, SC_SIZE | WMSZ_BOTTOM, MAKELPARAM(point.x, point.y));
        else if (nHitTest == HTLEFT)
            SendMessage( WM_SYSCOMMAND, SC_SIZE | WMSZ_LEFT, MAKELPARAM(point.x, point.y));
        else if (nHitTest == HTRIGHT)
            SendMessage( WM_SYSCOMMAND, SC_SIZE | WMSZ_RIGHT, MAKELPARAM(point.x, point.y));
        else if (nHitTest == HTTOPLEFT)
            SendMessage( WM_SYSCOMMAND, SC_SIZE | WMSZ_TOPLEFT, MAKELPARAM(point.x, point.y));
        else if (nHitTest == HTTOPRIGHT)
            SendMessage( WM_SYSCOMMAND, SC_SIZE | WMSZ_TOPRIGHT, MAKELPARAM(point.x, point.y));
        else if (nHitTest == HTBOTTOMLEFT)
            SendMessage( WM_SYSCOMMAND, SC_SIZE | WMSZ_BOTTOMLEFT, MAKELPARAM(point.x, point.y));
        else if (nHitTest == HTBOTTOMRIGHT)
            SendMessage(WM_SYSCOMMAND, SC_SIZE | WMSZ_BOTTOMRIGHT, MAKELPARAM(point.x, point.y));
        else if (nHitTest==HTCAPTION)
            SendMessage(WM_SYSCOMMAND, SC_MOVE | 4, MAKELPARAM(point.x, point.y));
    }
   
    CDialog::OnNcLButtonDown(nHitTest, point);
}