无焦点获取条码枪返回值示例

using system;
using system.collections.generic;
using system.linq;
using system.text;
using system.runtime.interopservices;
using system.reflection;

namespace booklibrarymanagement.commontools
{
    class barcodehook
    {
        public delegate void barcodedelegate(barcodes barcode);
        public event barcodedelegate barcodeevent;

        public struct barcodes
        {
            public int virtkey;      //虚拟码 
            public int scancode;     //扫描码 

            public string barcode;   //条码信息 
            public bool isvalid;     //条码是否有效 
            public datetime time;    //扫描时间 
        }

        private struct eventmsg
        {
            public int message;
            public int paraml;
            public int paramh;
            public int time;
            public int hwnd;
        }

        [dllimport("user32.dll", charset = charset.auto, callingconvention = callingconvention.stdcall)]
        private static extern int setwindowshookex(int idhook, hookproc lpfn, intptr hinstance, int threadid);

        [dllimport("user32.dll", charset = charset.auto, callingconvention = callingconvention.stdcall)]
        private static extern bool unhookwindowshookex(int idhook);

        [dllimport("user32.dll", charset = charset.auto, callingconvention = callingconvention.stdcall)]
        private static extern int callnexthookex(int idhook, int ncode, int32 wparam, intptr lparam);

        delegate int hookproc(int ncode, int32 wparam, intptr lparam);

        barcodes barcode = new barcodes();
        int hkeyboardhook = 0;
        list<char> _barcode = new list<char>(100);
        private int keyboardhookproc(int ncode, int32 wparam, intptr lparam)
        {
            if (ncode == 0)
            {
                eventmsg msg = (eventmsg)marshal.ptrtostructure(lparam, typeof(eventmsg));

                if (wparam == 0x100)   //wm_keydown = 0x100 
                {
                    barcode.virtkey = msg.message & 0xff;  //虚拟码 
                    barcode.scancode = msg.paraml & 0xff;  //扫描码 

                   
                    if (datetime.now.subtract(barcode.time).totalmilliseconds > 100)
                    {
                        _barcode.clear();
                    }
                    else
                    {
                        if ((msg.message & 0xff) == 13 && _barcode.count > 0)   //回车 
                        {
                            barcode.barcode = new string(_barcode.toarray());
                            barcode.isvalid = true;
                            _barcode.clear();
                        }
                    }

                    barcode.time = datetime.now;
                    if (barcodeevent != null) barcodeevent(barcode);    //触发事件 
                    barcode.isvalid = false;
                    _barcode.add(convert.tochar(msg.message & 0xff));
                }
            }
            return callnexthookex(hkeyboardhook, ncode, wparam, lparam);
        }

        private static hookproc hookproc;
        // 安装钩子  
        public bool start()
        {
            if (hkeyboardhook == 0)
            {
                hookproc = new hookproc(keyboardhookproc);
                //wh_keyboard_ll = 13 
                hkeyboardhook = setwindowshookex(13, hookproc, marshal.gethinstance(assembly.getexecutingassembly().getmodules()[0]), 0);
            }
            return (hkeyboardhook != 0);
        }

        // 卸载钩子  
        public bool stop()
        {
            if (hkeyboardhook != 0)
            {
                return unhookwindowshookex(hkeyboardhook);
            }
            return true;
        }
    }
}