WinForm特效:拦截窗体上各个部位的点击

        { WM_NCHITTEST and MOUSEHOOKSTRUCT Mouse Position Codes }
          {$EXTERNALSYM HTERROR}
          HTERROR = -2;
          {$EXTERNALSYM HTTRANSPARENT}
          HTTRANSPARENT = -1;
          {$EXTERNALSYM HTNOWHERE}
          HTNOWHERE = 0;
          {$EXTERNALSYM HTCLIENT}
          HTCLIENT = 1;
          {$EXTERNALSYM HTCAPTION}
          HTCAPTION = 2;
          {$EXTERNALSYM HTSYSMENU}
          HTSYSMENU = 3;
          {$EXTERNALSYM HTGROWBOX}
          HTGROWBOX = 4;
          {$EXTERNALSYM HTSIZE}
          HTSIZE = HTGROWBOX;
          {$EXTERNALSYM HTMENU}
          HTMENU = 5;
          {$EXTERNALSYM HTHSCROLL}
          HTHSCROLL = 6;
          {$EXTERNALSYM HTVSCROLL}
          HTVSCROLL = 7;
          {$EXTERNALSYM HTMINBUTTON}
          HTMINBUTTON = 8;
          {$EXTERNALSYM HTMAXBUTTON}
          HTMAXBUTTON = 9;
          {$EXTERNALSYM HTLEFT}
          HTLEFT = 10;
          {$EXTERNALSYM HTRIGHT}
          HTRIGHT = 11;
          {$EXTERNALSYM HTTOP}
          HTTOP = 12;
          {$EXTERNALSYM HTTOPLEFT}
          HTTOPLEFT = 13;
          {$EXTERNALSYM HTTOPRIGHT}
          HTTOPRIGHT = 14;
          {$EXTERNALSYM HTBOTTOM}
          HTBOTTOM = 15;
          {$EXTERNALSYM HTBOTTOMLEFT}
          HTBOTTOMLEFT = 16;
          {$EXTERNALSYM HTBOTTOMRIGHT}
          HTBOTTOMRIGHT = 17;
          {$EXTERNALSYM HTBORDER}
          HTBORDER = 18;
          {$EXTERNALSYM HTREDUCE}
          HTREDUCE = HTMINBUTTON;
          {$EXTERNALSYM HTZOOM}
          HTZOOM = HTMAXBUTTON;
          {$EXTERNALSYM HTSIZEFIRST}
          HTSIZEFIRST = HTLEFT;
          {$EXTERNALSYM HTSIZELAST}
          HTSIZELAST = HTBOTTOMRIGHT;
          {$EXTERNALSYM HTOBJECT}
          HTOBJECT = 19;
          {$EXTERNALSYM HTCLOSE}
          HTCLOSE = 20;
          {$EXTERNALSYM HTHELP}
          HTHELP = 21;