BCB:处理Windows消息

1.MESSAGE_HANDLER

public:
    BEGIN_MESSAGE_MAP
        MESSAGE_HANDLER(WM_NCHITTEST,TWMNCHitTest ,OnNcHitTest)
    END_MESSAGE_MAP(TForm)

    void __fastcall OnNcHitTest(TWMNCHitTest&);

//---------------------------------------------------------------------------
void __fastcall TForm1::OnNcHitTest(TWMNCHitTest& Msg)
{

        // 分解当前鼠标的坐标
         int nPosX = Msg.XPos;
        int nPosY = Msg.YPos;
        if(nPosX >= Left + Width - 2 && nPosY >= Top + Height - 2)
        {
            // 鼠标位置在窗体的右下角附近
            Msg.Result = HTBOTTOMRIGHT;
            return;
        }
        else if(nPosX >= Left + Width -2)
        {
            // 鼠标位置在窗体右侧
            Msg.Result = HTRIGHT;
            return;
        }
        else if(nPosY >= Top + Height - 2)
        {
            // 鼠标位置在窗体下方
            Msg.Result = HTBOTTOM;
            return;
        }

        TForm::Dispatch(&Msg);
}

2. 重写WndProc