请教：怎样监测到系统是否有键盘或鼠标事件

Question

截留系统消息
参考《Delphi 5 开发人员指南》

Answer 1

谢谢，我用HOOK搞定了，有一个例子可供大家参考
先是DLL
library HKTest;{ 按下Ctro+B，启动记事本 }uses
  SysUtils,
  Classes,
  HKProc in 'HKProc.pas';exports
  EnableHotKeyHook,
  DisableHotKeyHook;
begin
  hNextHookProc:=0;
  procSaveExit:= ExitProc;
  ExitProc:= @HotKeyHookExit;
end.unit HKProc;interfaceuses
  Windows, Messages, Dialogs,Shellapi;Var
  hNextHookProc: HHook;
  procSaveExit: Pointer;function KeyboardHookHandler(iCode: Integer;wParam: WPARAM;
                             lParam: LPARAM): LResult; stdcall; export;
function EnableHotKeyHook: Bool; export;
function DisableHotKeyHook: Bool; export;
procedure HotKeyHookExit; far;implementationfunction KeyboardHookHandler(iCode: Integer;wParam: WPARAM;
                             lParam: LPARAM): LResult; stdcall; export;
const
  _KeyPressMask = $80000000;
begin
  Result:=0;
  if iCode<0 then
  begin
    Result:= CallNextHookEx(hNextHookProc, iCode, wParam, lParam);
    exit;
  end;
  //侦测Ctrl+B组合键
  if ((lParam and _KeyPressMask)=0)and
    (GetKeyState(vk_control)<0)and(wParam=Ord('B')) then
  begin
    Result:=1;
    //ShellExecute(hInstance,'open','Notepad.exe','','',sw_Normal);
    WinExec('Notepad.exe',sw_Normal);
  end;
end;function EnableHotKeyHook: Bool; export;
begin
  Result:= False;
  if hNextHookProc<>0 then exit;
  //挂上WH_KEYBOARD 的HOOK， 同时，传回值必须保留下来，免的HOOK调用链断掉
  hNextHookProc:= SetWindowsHookEx(WH_KEYBOARD,KeyboardHookHandler,HInstance,0);
  Result:= hNextHookProc<>0;
end;function DisableHotKeyHook: Bool; export;
begin
  if hNextHookProc<>0 then
  begin
    UnHookWindowsHookEx(hNextHookProc);
    hNextHookProc:=0 ;
    MessageBeep(0);
    MessageBeep(0);
  end;
  Result:= hNextHookProc =0;
end;procedure HotKeyHookExit;
begin
  //如果忘了解除HOOK,自动代理解除的动作
  if hNextHookProc<>0 then DisableHotKeyHook;
  ExitProc:= procSaveExit;
end;
end.下面是测试程序
program hk;uses
  Forms,
  Unit1 in 'Unit1.pas' {Form1};{$R *.RES}begin
  Application.Initialize;
  Application.CreateForm(TForm1, Form1);
  Application.Run;
end.unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;type
  TForm1 = class(TForm)
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  Form1: TForm1;implementation{$R *.DFM}
  function EnableHotKeyHook: Bool;external 'HKTest.DLL';
  function DisableHotKeyHook: Bool;external 'HKTest.DLL';procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  if DisableHotKeyHook then
    Showmessage('HotKey Testing... DONE!!');
end;procedure TForm1.FormCreate(Sender: TObject);
begin
    if EnableHotKeyHook then
    Showmessage('HotKey Testing...');
end;end.这样按Ctrl+B就可调出写字板了