上一个例子是从 DLL 中接受数据, 那怎么给 DLL 传递数据呢? 还有, 在接受数据时, 让 Timer 一直在那扫描也不是个好办法呀. 本例解决了这些问题(但不知解决了博友 "鹏" 的问题没有?).
为了方便测试, 提供一个源码下载吧: http://files.cnblogs.com/del/MouseHook_2.rar
本例效果图(和上一例是一样的):
DLL 文件:
library MyHook;
uses
SysUtils,
Windows,
Messages,
Classes;
{$R *.res}
const WM_MyMessage = WM_USER + 1; {自定义消息}
var
hook: HHOOK;
info: string;
h: HWND; {用作外部窗口的句柄}
{获取外部窗口的句柄}
function SetHWnd(hwnd: HWND): Boolean; stdcall;
begin
h := hwnd;
Result := True;
end;
function MouseHook(nCode: Integer; wParam: WPARAM; lParam: LPARAM): LRESULT; stdcall;
begin
case wParam of
WM_MOUSEMOVE : info := '鼠标位置';
WM_LBUTTONDOWN : info := '按下';
WM_LBUTTONUp : info := '放开';
end;
info := Format('%s: %d,%d', [info, PMouseHookStruct(lParam)^.pt.X, PMouseHookStruct(lParam)^.pt.Y]);
{通过消息把数据传递给指定窗口}
PostMessage(h, WM_MyMessage, 0, Integer(PChar(info)));
Result := CallNextHookEx(hook, nCode, wParam, lParam);
end;
function SetHook: Boolean; stdcall;
const
WH_MOUSE_LL =14;
begin
hook := SetWindowsHookEx(WH_MOUSE_LL, @MouseHook, HInstance, 0);
Result := hook <> 0;
end;
function DelHook: Boolean; stdcall;
begin
Result := UnhookWindowsHookEx(hook);
end;
exports SetHook, DelHook, MouseHook, SetHWnd;
begin
end.
测试代码:
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ExtCtrls;
const WM_MyMessage = WM_USER + 1;
type
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
procedure FormCreate(Sender: TObject);
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure MyMessage(var msg: TMessage); message WM_MyMessage; {定义一个消息方法接受消息}
end;
function SetHook: Boolean; stdcall;
function DelHook: Boolean; stdcall;
function SetHWnd(hwnd: HWND): Boolean; stdcall;
var
Form1: TForm1;
implementation
{$R *.dfm}
function SetHook; external 'MyHook.dll';
function DelHook; external 'MyHook.dll';
function SetHWnd; external 'MyHook.dll';
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;
{把接受到的内容显示在窗体}
procedure TForm1.MyMessage(var msg: TMessage);
begin
Text := PChar(msg.LParam);
end;
end.