简单钩子程序

调用程序

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls, StrUtils, pubstr;

const
  WM_MyMessage = WM_USER + 1;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure MyMessage(var msg: TMessage); message WM_MyMessage; {定义一个消息方法接受消息}

  end;

function SetHook: Boolean; stdcall;external 'MyHook.dll';
function DelHook: Boolean; stdcall;external 'MyHook.dll';
function SetHWnd(hwnd: HWND): Boolean; stdcall;external 'MyHook.dll';

var
  Form1: TForm1;

implementation

{$R *.dfm}                             

procedure TForm1.Button1Click(Sender: TObject);
begin
  SetHook;
  SetHWnd(Handle);
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  DelHook;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Button1.Caption := '安装钩子';
  Button2.Caption := '载卸钩子';

  //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.MyMessage(var msg: TMessage);
begin
  Text := PChar(msg.LParam);
end;

end.

Dll  工程

library MyHook;

uses
  SysUtils,
  Windows,
  Messages,
  Classes;

{$R *.res}
const WM_MyMessage = WM_USER + 1; {自定义消息}

var
  hook: HHOOK;
  info: string;
  h: HWND; {用作外部窗口的句柄}

function SetHWnd(hwnd: HWND): Boolean; stdcall;
begin
  h := hwnd;
  Result := True;
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}
   {通过消息把数据传递给指定窗口}
  PostMessage(h, WM_MyMessage, 0, Integer(PChar(info)));

  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, SetHWnd;
begin
end.