delphi7 如何判断鼠标左右键事件?

Question

delphi7 如何判断鼠标左右键事件?想实现这个效果
http://hi.baidu.com/%D2%AC%D7%D3%CC%EC%D1%C4/album/item/f3e71eeae613129cb3fb953f.html#中间点击鼠标左键  两边各点击鼠标右键 

Answer 1

我是这样实现的 大家帮忙看看哪里出错了var
  poisCenter: TPoint;
  poisLine: TPoint;
  posiLeft: TPoint;
  posiRight: TPoint;
这些是全局变量
procedure TCyUsbCamera_frm.img1MouseDown(Sender: TObject;
  Button: TMouseButton; Shift: TShiftState; X, Y: Integer);var point: TPoint;
begin
  if Button = mbleft then
  begin
        begin
          with img1, Canvas do
          begin
            poisCenter := point;
            GetCursorPos(poisCenter);
            poisCenter := ScreenToClient(poisCenter);
          end;
        end;
  end else
    if Button = mbright then
    begin
        with img1, Canvas do
            begin
              if ((poisCenter.x <> 0) and (point.X < poisCenter.x)) then
              begin
                posiLeft := point;
                GetCursorPos(posiLeft);
                posiLeft := ScreenToClient(posiLeft);
              end else
                if (poisCenter.X <> 0) then
                begin
                  posiRight := point;
                  GetCursorPos(posiRight);
                  posiRight := ScreenToClient(posiRight);
                end;  
            end;
    end;
end;想实现如上图所示的效果 该怎么写？

Answer 2

你看看keyPress事件中 ，有一个参数是说 左键还是右键 还是中间滑轮的 ；

Answer 3

OnMouseDown事件里判断if button=mbLeft then   
  showmessage('1');   
if button=mbright then   
  showmessage('2');