抓取扫描枪扫描数据的案例

背景： Solution： view source print ?

001.1 using System;
002.2 using System.Collections.Generic;
003.3 using System.Linq;
004.4 using System.Runtime.InteropServices;
005.5 using System.Text;
006.6 using System.Threading.Tasks;
007.7 using System.Windows.Forms;
008.8
009.9 namespace MedicalMain
010.10 {
011.11 public class KeyboardHook
012.12 {
013.13 public event KeyEventHandler KeyDownEvent;
014.14 public event KeyPressEventHandler KeyPressEvent;
015.15 public event KeyEventHandler KeyUpEvent;
016.16
017.17 public delegate int HookProc(int nCode, Int32 wParam, IntPtr lParam);
018.18 static int hKeyboardHook = 0; //声明键盘钩子处理的初始值
019.19 //值在Microsoft SDK的Winuser.h里查询
020.20 public const int WH_KEYBOARD_LL = 13; //线程键盘钩子监听键盘消息设为2，全局键盘监听鼠标消息设为13
021.21 HookProc KeyboardHookProcedure; //声明KeyboardHookProcedure作为HookProc类型
022.22 //键盘结构
023.23 [StructLayout(LayoutKind.Sequential)]
024.24 public class KeyboardHookStruct
025.25 {
026.26 public int vkCode; //定一个虚拟键码。该代码必须有一个价值的范围1至254
027.27 public int scanCode; // 指定的硬件扫描码的关键
028.28 public int flags; // 键标志
029.29 public int time; // 指定的时间戳记的这个讯息
030.30 public int dwExtraInfo; // 指定额外信息相关的信息
031.31 }
032.32 //使用此功能，安装了一个钩子
033.33 [DllImport('user32.dll', CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
034.34 public static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);
035.35
036.36
037.37 //调用此函数卸载钩子
038.38 [DllImport('user32.dll', CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
039.39 public static extern bool UnhookWindowsHookEx(int idHook);
040.40
041.41
042.42 //使用此功能，通过信息钩子继续下一个钩子
043.43 [DllImport('user32.dll', CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
044.44 public static extern int CallNextHookEx(int idHook, int nCode, Int32 wParam, IntPtr lParam);
045.45
046.46 // 取得当前线程编号（线程钩子需要用到）
047.47 [DllImport('kernel32.dll')]
048.48 static extern int GetCurrentThreadId();
049.49
050.50 //使用WINDOWS API函数代替获取当前实例的函数,防止钩子失效
051.51 [DllImport('kernel32.dll')]
052.52 public static extern IntPtr GetModuleHandle(string name);
053.53
054.54 public void Start()
055.55 {
056.56 // 安装键盘钩子
057.57 if (hKeyboardHook == 0)
058.58 {
059.59 KeyboardHookProcedure = new HookProc(KeyboardHookProc);
060.60 hKeyboardHook = SetWindowsHookEx(WH_KEYBOARD_LL, KeyboardHookProcedure, GetModuleHandle(System.Diagnostics.Process.GetCurrentProcess().MainModule.ModuleName), 0);
061.61 //hKeyboardHook = SetWindowsHookEx(WH_KEYBOARD_LL, KeyboardHookProcedure, Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]), 0);
062.62 //************************************
063.63 //键盘线程钩子
064.64 //SetWindowsHookEx( 2,KeyboardHookProcedure, IntPtr.Zero, GetCurrentThreadId());//指定要监听的线程idGetCurrentThreadId(),
065.65 //键盘全局钩子,需要引用空间(using System.Reflection;)
066.66 //SetWindowsHookEx( 13,MouseHookProcedure,Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]),0);
067.67 //
068.68 //关于SetWindowsHookEx (int idHook, HookProc lpfn, IntPtr hInstance, int threadId)函数将钩子加入到钩子链表中，说明一下四个参数：
069.69 //idHook 钩子类型，即确定钩子监听何种消息，上面的代码中设为2，即监听键盘消息并且是线程钩子，如果是全局钩子监听键盘消息应设为13，
070.70 //线程钩子监听鼠标消息设为7，全局钩子监听鼠标消息设为14。lpfn 钩子子程的地址指针。如果dwThreadId参数为0 或是一个由别的进程创建的
071.71 //线程的标识，lpfn必须指向DLL中的钩子子程。 除此以外，lpfn可以指向当前进程的一段钩子子程代码。钩子函数的入口地址，当钩子钩到任何
072.72 //消息后便调用这个函数。hInstance应用程序实例的句柄。标识包含lpfn所指的子程的DLL。如果threadId 标识当前进程创建的一个线程，而且子
073.73 //程代码位于当前进程，hInstance必须为NULL。可以很简单的设定其为本应用程序的实例句柄。threaded 与安装的钩子子程相关联的线程的标识符
074.74 //如果为0，钩子子程与所有的线程关联，即为全局钩子
075.75 //************************************
076.76 //如果SetWindowsHookEx失败
077.77 if (hKeyboardHook == 0)
078.78 {
079.79 Stop();
080.80 throw new Exception('安装键盘钩子失败');
081.81 }
082.82 }
083.83 }
084.84 public void Stop()
085.85 {
086.86 bool retKeyboard = true;
087.87
088.88
089.89 if (hKeyboardHook != 0)
090.90 {
091.91 retKeyboard = UnhookWindowsHookEx(hKeyboardHook);
092.92 hKeyboardHook = 0;
093.93 }
094.94
095.95 if (!(retKeyboard)) throw new Exception('卸载钩子失败！');
096.96 }
097.97 //ToAscii职能的转换指定的虚拟键码和键盘状态的相应字符或字符
098.98 [DllImport('user32')]
099.99 public static extern int ToAscii(int uVirtKey, //[in] 指定虚拟关键代码进行翻译。
100.100 int uScanCode, // [in] 指定的硬件扫描码的关键须翻译成英文。高阶位的这个值设定的关键，如果是（不压）
101.101 byte[] lpbKeyState, // [in] 指针，以256字节数组，包含当前键盘的状态。每个元素（字节）的数组包含状态的一个关键。如果高阶位的字节是一套，关键是下跌（按下）。在低比特，如果设置表明，关键是对切换。在此功能，只有肘位的CAPS LOCK键是相关的。在切换状态的NUM个锁和滚动锁定键被忽略。
102.102 byte[] lpwTransKey, // [out] 指针的缓冲区收到翻译字符或字符。
103.103 int fuState); // [in] Specifies whether a menu is active. This parameter must be 1 if a menu is active, or 0 otherwise.
104.104
105.105 //获取按键的状态
106.106 [DllImport('user32')]
107.107 public static extern int GetKeyboardState(byte[] pbKeyState);
108.108
109.109
110.110 [DllImport('user32.dll', CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
111.111 private static extern short GetKeyState(int vKey);
112.112
113.113 private const int WM_KEYDOWN = 0x100;//KEYDOWN
114.114 private const int WM_KEYUP = 0x101;//KEYUP
115.115 private const int WM_SYSKEYDOWN = 0x104;//SYSKEYDOWN
116.116 private const int WM_SYSKEYUP = 0x105;//SYSKEYUP
117.117
118.118 private int KeyboardHookProc(int nCode, Int32 wParam, IntPtr lParam)
119.119 {
120.120 // 侦听键盘事件
121.121 if ((nCode >= 0) && (KeyDownEvent != null || KeyUpEvent != null || KeyPressEvent != null))
122.122 {
123.123 KeyboardHookStruct MyKeyboardHookStruct = (KeyboardHookStruct)Marshal.PtrToStructure(lParam, typeof(KeyboardHookStruct));
124.124 // raise KeyDown
125.125 if (KeyDownEvent != null && (wParam == WM_KEYDOWN || wParam == WM_SYSKEYDOWN))
126.126 {
127.127 Keys keyData = (Keys)MyKeyboardHookStruct.vkCode;
128.128 KeyEventArgs e = new KeyEventArgs(keyData);
129.129 KeyDownEvent(this, e);
130.130 }
131.131
132.132 //键盘按下
133.133 if (KeyPressEvent != null && wParam == WM_KEYDOWN)
134.134 {
135.135 byte[] keyState = new byte[256];
136.136 GetKeyboardState(keyState);
137.137
138.138 byte[] inBuffer = new byte[2];
139.139 if (ToAscii(MyKeyboardHookStruct.vkCode, MyKeyboardHookStruct.scanCode, keyState, inBuffer, MyKeyboardHookStruct.flags) == 1)
140.140 {
141.141 KeyPressEventArgs e = new KeyPressEventArgs((char)inBuffer[0]);
142.142 KeyPressEvent(this, e);
143.143 }
144.144 }
145.145
146.146 // 键盘抬起
147.147 if (KeyUpEvent != null && (wParam == WM_KEYUP || wParam == WM_SYSKEYUP))
148.148 {
149.149 Keys keyData = (Keys)MyKeyboardHookStruct.vkCode;
150.150 KeyEventArgs e = new KeyEventArgs(keyData);
151.151 KeyUpEvent(this, e);
152.152 }
153.153
154.154 }
155.155 //如果返回1，则结束消息，这个消息到此为止，不再传递。
156.156 //如果返回0或调用CallNextHookEx函数则消息出了这个钩子继续往下传递，也就是传给消息真正的接受者
157.157 return CallNextHookEx(hKeyboardHook, nCode, wParam, lParam);
158.158 }
159.159
160.160 ~KeyboardHook()
161.161 {
162.162 Stop();
163.163 }
164.164
165.165 }
166.166 }


键盘钩子功能类实现了，下面就是调用该类了，能够抓取到键盘的输入的每个值了
view source print ?

1.eyboardHook k_hook = new KeyboardHook();
2.k_hook.KeyDownEvent += new System.Windows.Forms.KeyEventHandler(hook_KeyDown);//钩住键按下
3.private void hook_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
4.{
5.///
6.}


view source print ?

01.1 ///

02.2 ///键盘按下触发的事件
03.3 ///

04.4 ///
05.5 ///
06.6 private void hook_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
07.7 {
08.8 string temp=string.Empty;
09.9 DateTime nowTime = DateTime.Now;
10.10 if ((e.KeyData >= Keys.D0 && e.KeyData <= Keys.D9) || (e.KeyData >= Keys.NumPad0 && e.KeyData <= Keys.NumPad9))//判断是不是数字的键盘值
11.11 temp = (e.KeyData.ToString()).Last().ToString();
12.12 else
13.13 temp = e.KeyData.ToString();
14.14 if((nowTime-previewTime).Milliseconds<20)//通过判断键盘输入的间隔来确定是扫描枪还是通过键盘输入的
15.15 {
16.16 if (e.KeyValue == (int)Keys.Return&&inputKey.Length>2)
17.17 {
18.18 this.tb_Key.Text = inputKey.ToString();
19.19 inputKey = new StringBuilder();
20.20 previewTime = DateTime.Now;
21.21 return;
22.22 }
23.23 inputKey.Append(temp);
24.24
25.25 }
26.26 else
27.27 {
28.28 inputKey=new StringBuilder(temp);
29.29 }
30.30 previewTime = DateTime.Now;
31.31 }


总结：