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function MouseHookProc(nCode: Integer; wPara: WPARAM; lPara: LPARAM): LRESULT; stdcall;
begin
  Result := CallNextHookEx(HookHandle, nCode, wPara, lPara);
  If nCode = hc_Action then
    begin
    If wPara = WM_LBUTTONDOWN then
      begin
      ShowMessage('Sende Nachricht.......');
      // SendMessage(WindowHandle, WM_MOUSEHOOKMSG, 0, 0);
      PostMessage(WindowHandle, WM_MOUSEHOOKMSG, 0, 0);
      end;
    end;
end;					

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const
  MouseMsg = 'MouseHook-Message';

var
  HookHandle : Cardinal = 0;
  ApplicationHandle : Cardinal = 0;
  WM_MOUSEHOOKMSG : Cardinal = 0;

function MouseHookProc(nCode: Integer; wPara: WPARAM; lPara: LPARAM):LRESULT; stdcall;
begin
  case wPara of
    WM_RBUTTONDOWN : PostMessage(ApplicationHandle, WM_MOUSEHOOKMSG, 0, 1);
    WM_LBUTTONDOWN : begin PostMessage(ApplicationHandle, WM_MOUSEHOOKMSG, 0, 2); Beep; end;
    end;
  Result := CallNextHookEx(HookHandle, nCode, wPara, lPara);
end;

function InstallHook(Handle: HWND): Boolean; stdcall;
begin
  Result := false;
  If HookHandle = 0 then
    begin
    HookHandle := SetWindowsHookEx(WH_MOUSE, @MouseHookProc, hInstance, 0);
    ApplicationHandle := Handle;
    ShowMessage(IntToStr(ApplicationHandle));
    WM_MOUSEHOOKMSG := RegisterWindowMessage(MouseMsg);
    Result := true;
    end;
end;

function UninstallHook: Boolean; stdcall;
begin
  Result := UnhookWindowsHookEx(HookHandle);
end;

exports
  InstallHook,
  UninstallHook;
end.