使用鉤子函式 5 資料傳遞

前言: 博友 "鵬" 來信**關於鉤子的問題, 核心困難是: dll 中的資料如何傳遞出來. 在接下來的兩個例子中**這個問題.

本例建立乙個全域性的滑鼠鉤子, 然後把滑鼠的相關資訊通過乙個自定義的 getinfo 函式傳遞給呼叫鉤子的程式.

本例效果圖:

dll 檔案:

library myhook;

uses
sysutils,
windows,
messages,
classes;
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 := '滑鼠位置';
wm_lbuttondown : info := '按下';
wm_lbuttonup   : info := '放開';
end;
info := format('%s: %d,%d', [info, pmousehookstruct(lparam)^.pt.x, pmousehookstruct(lparam)^.pt.y]);
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, getinfo;
begin
end.

unit unit1;

inte***ce
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
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 := '安裝鉤子';
button2.caption := '載卸鉤子';
timer1.interval := 100;
timer1.enabled := false;
formstyle := fsstayontop; 
end;
procedure tform1.formdestroy(sender: tobject);
begin
delhook;
end;
procedure tform1.timer1timer(sender: tobject);
begin
text := getinfo;
end;
end.

object form1: tform1

left = 0
top = 0
caption = 'form1'
clientheight = 78
clientwidth = 271
color = clbtnface
font.charset = default_charset
font.color = clwindowtext
font.height = -11
font.name = 'tahoma'
font.style = 
oldcreateorder = false
oncreate = formcreate
ondestroy = formdestroy
pixelsperinch = 96
textheight = 13
object button1: tbutton
left = 48
top = 32
width = 75
height = 25
caption = 'button1'
taborder = 0
onclick = button1click
endobject button2: tbutton
left = 144
top = 32
width = 75
height = 25
caption = 'button2'
taborder = 1
onclick = button2click
endobject timer1: ttimer
ontimer = timer1timer
left = 128
top = 8
endend

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