在Windows操作系统中,当用户按下"PrintScreen"按钮后,Windows自动将当前屏幕的图像拷贝到系统剪贴板中,这时可以通过"画笔"这个小程序将剪贴板中的内容保存成图像文件,可以看出,如果需要将当前屏幕保存下来还是比较麻烦的,能否可以自己编写一个应用程序,自动将当前屏幕的内容保存到一个图像文件中去呢?这个答案是肯定的,本实例应用程序就是利用通用的热键管理DLL库实现的热键功能,在收到热键通知后截取屏幕的内容并保存到bmp文件中。例如我们设置图片保存路径为c:\,热键为F9 + Control,然后按Change按钮设置好热键,那么当我们按下CTRL+F9后,当前界面将以BMP图像文件的格式被保存在C:\目录下。程序编译运行后的界面效果如图一所示:
c~5#)AXMT
1.p?P]
. 一、实现方法
pvI(hjMYPk Uf4QQ`c# 热键管理DLL实际上是一个键盘钩子,由它来监视系统的键盘事件。如果有和程序登记符合的按键组合就通知该程序的窗口。为了应用方便,本实例把它做成了一个标准的管理库来为其它的程序通过热键服务,它有两个输出函数:AddHotkey()和DeleteHotkey(),程序只需要调用这两个函数就可以了,如果编译之后不用改变热键,则只需要AddHotkey就可以了。DLL中的所有的全局变量都放在一个共享段中,定义如下:
>u*woNw(XM d=oOMXYa #pragma data_seg("shareddata")
I%e7:cs > HHOOK hHook =NULL; //钩子句柄
JV36@DVQ UINT nHookCount =0; //挂接的程序数目
c5;YKON static UCHAR HotKey[MAX_KEY] = {0}; //热键虚拟键码
cuq7eMG6z static UCHAR HotKeyMask[MAX_KEY] = {0}; //组合掩码, control=4,alt=2,shift=1
at,Xad\j static HWND hCallWnd[MAX_KEY] = {0}; //window handle associated with hotkey
tPO.^ static int KeyCount =0;
?9H7Twi+T static UCHAR MaskBits =0; //00000 Ctrl=4 & Alt=2 & Shift=1
**_VNDK+ #pragma data_seg()
|GdA0y\v*} +A~lPXAXW 关于共享段,有几点重要的说明:一是必须在链接选项里指定该段为共享:一种方法是在project->settings->link->object/library中加上/section:shareddata,rws;第二种方法是在def文件的sections里加上一句shareddata read write shared;第三种指定共享段的方法在程序里加上一句#pragma comment(linker,"section:shareddata,rws")。二是所有的变量必须初始化,否则链接程序会把它放到普通数据段。三是如果不初始化变量,需要在段外用"__declspec(allocate("shareddata")) 变量类型 变量名"的方式定义。
R:E6E@T <j:3<''o DLL中的两个输出函数分别用来添加/删除热键,函数代码如下:
XhWMvme v0"|J3 BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR
(pi7TSJ cKey,UCHAR cMask)
{)4Vv`n {
F#X\}MvEU BOOL bAdded=FALSE;
L9Fx
Lw41 for(int index=0;index<MAX_KEY;index++){
"'t<R}t!A if(hCallWnd[index]==0){
u+I-!3J87 hCallWnd[index]=hWnd;
{@Diig HotKey[index]=cKey;
:]y;t/ HotKeyMask[index]=cMask;
Se0/ysVB bAdded=TRUE;
Ct }"o KeyCount++;
hf:n!+,C break;
&Eidc . }
a(x[+ El }
aCGPtA' return bAdded;
_9!Ru!u~ }
Qi=rhN` //删除热键
M? [lpH3 BOOL __declspec(dllexport) __stdcall DeleteHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
JO :m:
M {
3C_g)5
_: BOOL bRemoved=FALSE;
)@R:$l86 for(int index=0;index<MAX_KEY;index++){
^z[s;:- if(hCallWnd[index]==hWnd){
\RQ5$!O if(HotKey[index]==cKey&&HotKeyMask[index]==cMask){
.8b4 hCallWnd[index]=NULL;
P2`ks[u+i HotKey[index]=0;
%ef+Z HotKeyMask[index]=0;
Mh~T.;f.qq bRemoved=TRUE;
V9Au\ KeyCount--;
>x2T' break;
wf|CE410 }
!c SD9q* }
Vg:P@6s }
aj(M{gFq~ return bRemoved;
)&_{m
K }
ZmmuP/~2K Tw!x* c}QQ8'_ DLL中的钩子函数如下:
*\S>dhJ4 {/QpEd>3+ LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
?a}eRA7 {
(]7@0d88 BOOL bProcessed=FALSE;
,P auP~L if(HC_ACTION==nCode)
NA/+bgyuT> {
*
+OAc`8 if((lParam&0xc0000000)==0xc0000000){// 有键松开
XJ?@l3D: switch(wParam)
+Kf::[wP7 {
J,7_5V@jJ case VK_MENU:
h$ZF[Xbfe
MaskBits&=~ALTBIT;
_^P>@
^ break;
5+ fS$Q
case VK_CONTROL:
Cs]xs9 MaskBits&=~CTRLBIT;
0
|F(qR break;
_ORW'(:Z case VK_SHIFT:
^+GN8LUs MaskBits&=~SHIFTBIT;
?7G[`@^Y
break;
p%3';7W\ default: //judge the key and send message
#(
kT break;
#e8CuS }
K[?wP>s for(int index=0;index<MAX_KEY;index++){
FfD2
&(-R if(hCallWnd[index]==NULL)
29av8eW?3 continue;
PY>j?otD if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
<m@U`RFm {
F&cA!~ SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
:"QRB#EC% bProcessed=TRUE;
i^QcW!X& }
(qPZEZKx }
%+pXzw`B }
<78>6u/W% else if((lParam&0xc000ffff)==1){ //有键按下
k?S-peyRO switch(wParam)
)3G?5
OTS {
A@DIq/^xM case VK_MENU:
Qz$.t>@V= MaskBits|=ALTBIT;
?C $_?Qi break;
J41ZQ case VK_CONTROL:
2l\Oufer" MaskBits|=CTRLBIT;
S:1! )7 break;
V).M\ case VK_SHIFT:
.pdgRjlSn MaskBits|=SHIFTBIT;
?^"S%Vb break;
E*
lqC h default: //judge the key and send message
@l;f';+ break;
O]~p)E }
x`o_&09;CG for(int index=0;index<MAX_KEY;index++){
w6wXe_N+M if(hCallWnd[index]==NULL)
OKf/[hyu continue;
ol:_2G2xQ if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
[n:R]|^a {
]]7s9PCN SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
fq F1-% bProcessed=TRUE;
Y:byb68 }
eA+6-'qN }
$hE X, }
Wo2M}]0 if(!bProcessed){ //一般按键事件,为监视键盘的程序留出余地
h[lh01z for(int index=0;index<MAX_KEY;index++){
dvXu?F55 if(hCallWnd[index]==NULL)
M~"K@g=Wr continue;
`q5*VqIhs if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
HX=`kkX SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
_C*}14
"3 //lParam的意义可看MSDN中WM_KEYDOWN部分
z!F?#L5 }
t;4{l`dk }
`[:f;2(@ }
Ng-3|N return CallNextHookEx( hHook, nCode, wParam, lParam );
Pd@?(WQ }
HZP`u >. 0#yo\McZ 抓图程序是一个基于对话框的程序,它在建立对话框的时候调用前面的DLL,登记热键,因此需要将hook.lib添加到工程里,在程序里给出两个DLL函数的定义,也可以写个头文件,再包含进来以下代码:
Y)a 7osML @|cas|U.r BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
r-!8in2 BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
ChBZGuO: XS1>ti|< 为了添加应用程序对热键通知事件的响应,程序中用的办法是重载WindowProc()函数,该函数代码如下:
/sYD+*a U,+=>ns> LRESULT CCaptureDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
CF$^we {
y\@XW*_? if(message==WM_HOTKEY&&lParam==WM_KEYDOWN)
0<P
-` |X {
yt<K!=7& //lParam表示是按下还是松开,如果有多个热键,由wParam来区分
^ 5UIbA( SaveBmp();
Qb SX'mx< return FALSE;
4W1"=VL[g }
|\b*p:el …… //其它处理及默认处理
K(Cv9YQ }
/[us;=CM *.i`hfRc nNL9B~d 将屏幕图像保存到BMP文件中的任务是由函数SaveBmp()来完成的,具体实现参见代码部分。另外为了顺利实现屏幕抓图,程序中还实现了"托盘"功能,由于这一部分本书在实例中已经专门介绍过了,所以不再赘述,读者朋友可以参考相关实例。
k'S/nF A &PGU%"rN 最后需要提醒读者朋友们注意的是,源程序的编译与使用时要先编译hook.dll并将其放在系统目录(win2000/NT是system32,98/ME是system),然后编译对话框程序运行即可。
g.,IQ4o ,7/N=mz 二、编程步骤
M/#<=XhA EmH2 Dbw 1、 启动Visual C++,生成一个DLL项目和一个基于对话框的应用程序项目,并将两个项目分别命名为"Hook"和"Capture";
yCmiW
%L4 X#pE!mT 2、 在"Hook"项目中导出AddHotkey()、DeleteHotkey()函数;
OP>'<FK /gPn2e; 3、 在"Capture"项目中按照图一所示设置对话框的界面,具体设置参见代码部分;
3
D+dM0wM >S!QvyM(V 4、 使用Class Wizard在"Capture"项目中添加按钮的鼠标单击消息响应函数,并重载对话框的WindowProc()函数;
^Ji5)c km8[azB o 5、 添加代码,编译运行程序。
+='.uc_ j[c|np4k\ 三、程序代码
SFh6'v'1N@ Z,Q)\W<'- ///////////////////////////////////// Hook.h : main header file for the HOOK DLL
R[Pyrs!H #if !defined(AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_)
ymzlRs1^Ct #define AFX_HOOK_H__AEBFF705_C93A_11D5_B7D6_0080C82BE86B__INCLUDED_
N.3M~0M*
#if _MSC_VER > 1000
}9@,EEhg #pragma once
*%Q!22?6F #endif // _MSC_VER > 1000
oU{m\r #ifndef __AFXWIN_H__
2AU_<Hr6 #error include 'stdafx.h' before including this file for PCH
^S[Mg6J #endif
jMZ{>l.v #include "resource.h" // main symbols
4Kx;F
9!%~ class CHookApp : public CWinApp
wLNO\JP' {
!v94FkS> public:
b^FB[tZ\x CHookApp();
:~g=n&x // Overrides
0h$23. // ClassWizard generated virtual function overrides
mNs&*h} //{{AFX_VIRTUAL(CHookApp)
7zy6`OP public:
bl:.D~@ virtual BOOL InitInstance();
jYuH
zf virtual int ExitInstance();
&grT} //}}AFX_VIRTUAL
H{9di\xnEm //{{AFX_MSG(CHookApp)
h*&-[nSo // NOTE - the ClassWizard will add and remove member functions here.
lB3W|-Ci // DO NOT EDIT what you see in these blocks of generated code !
Li iQ;x //}}AFX_MSG
347p2sK> DECLARE_MESSAGE_MAP()
#uFP
eu: };
rr2|xL?+u LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam);
/ 1g_Uv; BOOL __declspec(dllexport)__stdcall AddHotkey(HWND,UCHAR key,UCHAR mask);
>Ei_## BOOL __declspec(dllexport)__stdcall DeleteHotkey(HWND,UCHAR key,UCHAR mask);
4Yx?75/ BOOL InitHotkey();
@R>J\> BOOL UnInit();
a B%DIH, #endif
rT5dv3^MW! g)2}`} //////////////////////////////////////// Hook.cpp : Defines the initialization routines for the DLL.
#(!> #include "stdafx.h"
lcyan #include "hook.h"
vMDV%E S1t #include <windowsx.h>
<+pwGKtD #ifdef _DEBUG
pT.iQ J| #define new DEBUG_NEW
c`AtKs)u #undef THIS_FILE
WOR~tS static char THIS_FILE[] = __FILE__;
G'Jsk4:c #endif
Al6)$8]e #define MAX_KEY 100
oJ>]=^?k #define CTRLBIT 0x04
k)dLJ<EM #define ALTBIT 0x02
OZs^c2
W #define SHIFTBIT 0x01
1Y\g{A" #pragma data_seg("shareddata")
kC0F@'D HHOOK hHook =NULL;
)"wWV{k UINT nHookCount =0;
-+ -@Yq$ static UCHAR HotKey[MAX_KEY] = {0}; //hotkey
^6oz3+ static UCHAR HotKeyMask[MAX_KEY] = {0}; //flag for hotkey, value is VK_CONTRL or VK_NEMU or VK_SHIFT
Mb uD8B static HWND hCallWnd[MAX_KEY] = {0}; //window associated with hotkey
XeKIue@_ static int KeyCount =0;
HTvA]-AuM static UCHAR MaskBits =0; //00000 Ctrl Alt Shift
8(7DW
|\ #pragma data_seg()
+P81&CaY HINSTANCE hins;
U"af3c^2 void VerifyWindow();
9JpPas$] BEGIN_MESSAGE_MAP(CHookApp, CWinApp)
$9j\sZj& //{{AFX_MSG_MAP(CHookApp)
; Sq_DP1W // NOTE - the ClassWizard will add and remove mapping macros here.
&}Cm9V // DO NOT EDIT what you see in these blocks of generated code!
pQ!NhzQ //}}AFX_MSG_MAP
[n44; END_MESSAGE_MAP()
xP
"7B9B >@rsh-Z CHookApp::CHookApp()
c54oQ1Q&" {
j0~]o})@i // TODO: add construction code here,
L"P$LEk // Place all significant initialization in InitInstance
SBgBZm}% }
3g`uLA X>u :q<8:,rP CHookApp theApp;
00[Uk'Q*5 LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam)
lqTTTk {
y}FTLX $ BOOL bProcessed=FALSE;
tQ&.;{5[f if(HC_ACTION==nCode)
LaG./+IP {
pMe'fC~* if((lParam&0xc0000000)==0xc0000000){// Key up
NVAt-u0LB switch(wParam)
yL7D;<!S& {
u`O
xY case VK_MENU:
P=OHiG\z MaskBits&=~ALTBIT;
q
okgu$2 break;
L
Me{5H case VK_CONTROL:
z}&?^YU*)` MaskBits&=~CTRLBIT;
D4$;jz,, break;
?<STt 9 case VK_SHIFT:
4#1[i|:M MaskBits&=~SHIFTBIT;
MuQyHEDF break;
uckag/tv default: //judge the key and send message
yF8 av=<{ break;
?~Fk_#jz,@ }
6-c3v for(int index=0;index<MAX_KEY;index++){
}K!}6?17T if(hCallWnd[index]==NULL)
p'M5]G continue;
[#.E=s+& if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
m-dyvW+ {
XXBN
Nr_CK SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYUP);
^$}9
Enj+Y bProcessed=TRUE;
6sJN@dFA }
FctqE/>}I }
J\^ZRu_K }
<C`qJP- else if((lParam&0xc000ffff)==1){ //Key down
,]+P#eXgE switch(wParam)
cah1'Y {
^mz&L|h case VK_MENU:
mEyJ
o| MaskBits|=ALTBIT;
]3uErnI break;
c=p`5sN) case VK_CONTROL:
,u8)g;8s MaskBits|=CTRLBIT;
G1=GzAd$5 break;
$T.we+u case VK_SHIFT:
<csz4tL}P MaskBits|=SHIFTBIT;
BU(:6 break;
xb1 i{d default: //judge the key and send message
>~8;H x].d break;
;[V_w/-u }
_w0t+=& for(int index=0;index<MAX_KEY;index++)
^1^k< {
:L*"OT7(6 if(hCallWnd[index]==NULL)
#Drs=7w continue;
,5$V;| if(IsWindow(hCallWnd[index])&&(HotKey[index]==wParam)&&(HotKeyMask[index]==MaskBits))
,K'>s<} {
SR7$m<0t* SendMessage(hCallWnd[index],WM_HOTKEY,wParam,WM_KEYDOWN);
0*^ J;QGE bProcessed=TRUE;
i`U:uwW` }
1BO$xq }
EhL
8rR }
/`McKYIP if(!bProcessed){
K<TVp;N for(int index=0;index<MAX_KEY;index++){
WDQtj$e+ if(hCallWnd[index]==NULL)
G5a PjP continue;
(ZH5/VKp if(IsWindow(hCallWnd[index])&&(HotKey[index]==0)&&(HotKeyMask[index]==0))
|:BKexjHL SendMessage(hCallWnd[index],WM_HOTKEY,WM_HOTKEY,lParam);
Fr_esx }
5G"LuA }
+RWP;rk }
o=@0Bd8 return CallNextHookEx( hHook, nCode, wParam, lParam );
*5?a%p }
RZ 4xR {G$I|<MD2T BOOL InitHotkey()
ChO?Lm$y {
uTTM%-DMHT if(hHook!=NULL){
})RT2zw} nHookCount++;
1henQiIO return TRUE;
8s(?zK\ }
q_S`@2Dzz, else
S81Z\=eK hHook=SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KeyboardProc,hins,0);
Ww-%s9N< if(hHook!=NULL)
#2l6'gWE0 nHookCount++;
Fb#.Gg9b> return (hHook!=NULL);
=%P'?(o| }
acr@erk BOOL UnInit()
E]$YM5 {
Jf6uE?. if(nHookCount>1){
.#0),JJZ[ nHookCount--;
FYq]-k{\ return TRUE;
9ZFvN*Zf' }
7fRL'I#[@ BOOL unhooked = UnhookWindowsHookEx(hHook);
KzD5>Xf]4$ if(unhooked==TRUE){
o (fZZ`6Y nHookCount=0;
g-lF{Z hHook=NULL;
5y-8_)y8o }
-wv5c return unhooked;
7.g)_W{7} }
X{KWBk.1 ?g9mDe;k BOOL __declspec(dllexport) __stdcall AddHotkey(HWND hWnd,UCHAR cKey,UCHAR cMask)
dayp1%d {
6QS[mWU BOOL bAdded=FALSE;
!9|)v7} for(int index=0;index<MAX_KEY;index++){
*:
)hoHp&