IntToStr(wParam)); {参数二是键值} Result := 0; {分别测试返回 0 或非 0 这两种情况} end; {派出钩子} procedure TForm1.Button1Click(Sender: TObject); begin hook := SetWindowsHookEx(WH_KEYBOARD, MyKeyHook, HInstance, GetCurrentThreadId); Memo1.Clear; Text := '钩子启动'; end; {收回钩子} procedure TForm1.Button2Click(Sender: TObject); begin UnhookWindowsHookEx(hook); Text := '钩子关闭'; end; {如果忘了收回钩子...} procedure TForm1.FormDestroy(Sender: TObject);
begin if hook<>0 then UnhookWindowsHookEx(hook); end; end.[/code] 提示:在 SetWindowsHookEx 时, 第二参数(函数地址), 没有使用 @、 也没有用 Addr, 怎么也行呢? 因为函数名本身就是个地址. 例子一;本例建立一个全局的鼠标钩子, 然后把鼠标的相关信息通过一个自定义 的 GetInfo 函数传递给调用钩子的程序. [code=delphi] DLL 文件: library MyHook; uses SysUtils, Windows, Messages, Classes; {$R *.res} var hook: HHOOK; info: string; function GetInfo: PChar; begin Result := PChar(info); end; function MouseHook(nCode: Integer; wParam: WPARAM; lParam: LPARAM): LRESULT; stdcall; begin case wParam of WM_MOUSEMOVE : info := '鼠标位置'; WM_LBUTTONDOWN : info := '按下'; WM_LBUTTONUp : info := '放开'; end; info := Format('%s: %d,%d', [info, PMouseHookStruct(lParam)^.pt.X, PMouseHookStruct(lParam)^.pt.Y]);
{此信息可通过 GetInfo 函数从外部提取} Result := CallNextHookEx(hook, nCode, wParam, lParam); end; function SetHook: Boolean; stdcall; const WH_MOUSE_LL =14; {
Delphi 少给了两个常量: WH_KEYBOARD_LL = 13; WH_MOUSE_LL = 14; 需要时自己定义} begin hook := SetWindowsHookEx(WH_MOUSE_LL, @MouseHook, HInstance, 0); {WH_MOUSE 只是线程级的} Result := hook <> 0; end; function DelHook: Boolean; stdcall; begin Result := UnhookWindowsHookEx(hook); end; exports SetHook, DelHook,
MouseHook, GetInfo; begin end.[/code] 测试代码: [code=delphi] unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls; type TForm1 = class(TForm) Button1: TButton; Button2: TButton; Timer1: TTimer; procedure FormCreate(Sender: TObject); procedure Button1Click(Sender: TObject); procedure Button2Click(Sender: TObject); procedure Timer1Timer(Sender: TObject); procedure FormDestroy(Sender: TObject);
end; function SetHook: Boolean; stdcall; function DelHook: Boolean; stdcall; function GetInfo: PChar; stdcall; var Form1: TForm1; implementation {$R *.dfm} function SetHook; external 'MyHook.dll'; function DelHook; external 'MyHook.dll'; function GetInfo; external 'MyHook.dll'; procedure TForm1.Button1Click(Sender: TObject); begin SetHook; Timer1.Enabled := True; end; procedure TForm1.Button2Click(Sender: TObject); begin Timer1.Enabled := False; DelHook; end; procedure TForm1.FormCreate(Sender: TObject); begin Button1.Caption := '安装钩子'; Button2.Caption := '载卸钩子'; Timer1.Interval := 100; Timer1.Enabled := Fal se; FormStyle := fsStayOnTop; {为了测试, 让窗口一直在前面} end; procedure TForm1.FormDestroy(Sender: TObject); begin DelHook; end;
procedure TForm1.Timer1Timer(Sender: TObject); begin Text := GetInfo; end; end.[/code] 测试窗体: [code=delphi] object Form1: TForm1 Left = 0 Top = 0 Caption = 'Form1' ClientHeight = 78 ClientWidth = 271 Color = clBtnFace Font.Charset = DEFAULT_CHARSET Font.Color = clWindowText Font.Height = -