通过串口设备vid，pid自动获得该设备所对应的串口号

用C#做串口通讯很方便，因为dotfx2.0已经集成了Serial Port控件，此控件使用上比MSComm控件更简单，当然它也有一个小bug

（RecievedBytesThreshold设置有时候不好使），但是这个问题很好解决，而做串口通讯最最基本的问题就是如何获得目标机器的要与

之通讯的特定设备的特定com号，有许多软件在处理这个问题的时候都是要求用户手动去选择对应的串口号，这多少有些不人性化，这篇

文章就是介绍如何自动获得目标机器对应特定串口设备的串口号，从而达到软件与目标设备的自动通讯。
  方法基本上是我前一篇文章的一个应用，代码如下（注意自己添加引用的命名空间）
// <summary>
        /// 通过vid，pid获得串口设备号
        /// </summary>
        /// <param name="vid">vid</param>
        /// <param name="pid">pid</param>
        /// <returns>串口号</returns>
        public static string GetPortNameFormVidPid(string vid, string pid)
        {
            Guid myGUID = Guid.Empty;
            string enumerator = "USB";
            try
            {
                IntPtr hDevInfo = HardWareLib.SetupDiGetClassDevs(ref myGUID, enumerator, IntPtr.Zero, 

HardWareLib.DIGCF_ALLCLASSES | HardWareLib.DIGCF_PRESENT);
                if (hDevInfo.ToInt32() == HardWareLib.INVALID_HANDLE_VALUE)
                {
                    throw new Exception("没有该类设备");
                }
                HardWareLib.SP_DEVINFO_DATA deviceInfoData;//想避免在api中使用ref，就把structure映射成类
                deviceInfoData = new HardWareLib.SP_DEVINFO_DATA();
                deviceInfoData.cbSize = 28;//如果要使用SP_DEVINFO_DATA，一定要给该项赋值28=16+4+4+4
                deviceInfoData.devInst = 0;
                deviceInfoData.classGuid = System.Guid.Empty;
                deviceInfoData.reserved = 0;
UInt32 i;
                StringBuilder property = new StringBuilder(HardWareLib.MAX_DEV_LEN);
                for (i = 0; HardWareLib.SetupDiEnumDeviceInfo(hDevInfo, i, deviceInfoData); i++)
                {
                    //       Console.Write(deviceInfoData.classGuid.ToString());
                    //       HardWareOperation.SetupDiGetDeviceInstanceId(hDevInfo, deviceInfoData, porperty, (uint)

porperty.Capacity, 0);
                    HardWareLib.SetupDiGetDeviceRegistryProperty(hDevInfo, deviceInfoData,
                        (uint)HardWareLib.SPDRP_.SPDRP_CLASS,
                        0, property, (uint)property.Capacity, IntPtr.Zero);
                    if (property.ToString().ToLower() != "ports") continue;//首先看看是不是串口设备（有些USB设备不是串口设备）
                    HardWareLib.SetupDiGetDeviceRegistryProperty(hDevInfo, deviceInfoData,
                        (uint)HardWareLib.SPDRP_.SPDRP_HARDWAREID,
                        0, property, (uint)property.Capacity, IntPtr.Zero);
                    if (!(property.ToString().ToLower().Contains(vid.ToLower())
                        && property.ToString().ToLower().Contains(pid.ToLower()))) continue;//找到对应于vid&pid的设备
                    HardWareLib.SetupDiGetDeviceRegistryProperty(hDevInfo, deviceInfoData,
                        (uint)HardWareLib.SPDRP_.SPDRP_FRIENDLYNAME,
                        0, property, (uint)property.Capacity, IntPtr.Zero);
                    break;

                }
HardWareLib.SetupDiDestroyDeviceInfoList(hDevInfo);//记得用完释放相关内存
                string friendlyName = property.ToString();
                string pattern=@"(COM[1-9][0-9]?)$";//friendlyName一般形式为以(COMn)结尾，n为1-99
                if (Regex.IsMatch(friendlyName, pattern, RegexOptions.IgnoreCase))
                {
                    string portName=Regex.Match(friendlyName, pattern, RegexOptions.IgnoreCase).Value;
                    return portName.Trim(new char[] { '(', ')' });
                }
                return null;
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
                return null;
            }
        }
HardWareLib.cs(也就是前一篇文章的一个类)
using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;

namespace ForGeneralUse
{
    public class HardWareLib
    {
        /// <summary>
        /// 设备的各项属性，注意有些属性是不通用的，例如SPDRP_FRIENDLYNAME只适用于端口设备
        /// </summary>
        public enum SPDRP_
        {
            SPDRP_DEVICEDESC = (0x00000000),  // DeviceDesc (R/W)
            SPDRP_HARDWAREID = (0x00000001),  // HardwareID (R/W)
            SPDRP_SERVICE = (0x00000004), // Service (R/W)
            SPDRP_CLASS = (0x00000007),  // Class (R--tied to ClassGUID)
            SPDRP_CLASSGUID = (0x00000008),  // ClassGUID (R/W)
            SPDRP_DRIVER = (0x00000009),  // Driver (R/W)
            SPDRP_CONFIGFLAGS = (0x0000000A), // ConfigFlags (R/W)
            SPDRP_MFG = (0x0000000B), // Mfg (R/W)
            SPDRP_FRIENDLYNAME = (0x0000000C),  // FriendlyName (R/W)
            SPDRP_PHYSICAL_DEVICE_OBJECT_NAME = (0x0000000E),  // PhysicalDeviceObjectName (R)
            SPDRP_CAPABILITIES = (0x0000000F), // Capabilities (R)
            SPDRP_REMOVAL_POLICY_HW_DEFAULT = (0x00000020),  // Hardware Removal Policy (R)
            SPDRP_INSTALL_STATE = (0x00000022), // Device Install State (R)
        }
public const int DIGCF_ALLCLASSES = (0x00000004);
        public const int DIGCF_DEVICEINTERFACE = 0x00000010;
        public const int DIGCF_PRESENT = (0x00000002);
        public const int INVALID_HANDLE_VALUE = -1;
        public const int MAX_DEV_LEN = 1000;

        /// <summary>
        /// 获取一个指定类别或全部类别的所有已安装设备的信息
        /// </summary>
        /// <param name="gClass">该类别对应的guid</param>
        /// <param name="iEnumerator">类别名称（在HKLMSYSTEMCurrentControlSetEnum内获取）</param>
        /// <param name="hParent">应用程序定义的窗口句柄</param>
        /// <param name="nFlags">获取的模式</param>
        /// <returns>设备信息集合的句柄</returns>
        [DllImport("setupapi.dll", SetLastError = true, CharSet = CharSet.Auto)]
        public static extern IntPtr SetupDiGetClassDevs(ref Guid gClass, String enumerator, IntPtr hParent, UInt32 nFlags);

        /// <summary>
        /// 获得该设备的设备范例ID
        /// </summary>
        /// <param name="DeviceInfoSet">设备信息集合</param>
        /// <param name="DeviceInfoData">表示该设备</param>
        /// <param name="DeviceInstanceId">设备范例ID（输出）</param>
        /// <param name="DeviceInstanceIdSize">该ID所占大小（字节）</param>
        /// <param name="RequiredSize">需要多少字节</param>
        /// <returns>是否成功</returns>
        DllImport("setupapi.dll", SetLastError = true)]
        public static extern bool SetupDiGetDeviceInstanceId(IntPtr DeviceInfoSet,
                                    HardWareLib.SP_DEVINFO_DATA DeviceInfoData,
                                    StringBuilder DeviceInstanceId,
                                    UInt32 DeviceInstanceIdSize,
                                    UInt32 RequiredSize);

        /// <summary>
        /// 枚举指定设备信息集合的成员，并将数据放在SP_DEVINFO_DATA中
        /// </summary>
        /// <param name="lpInfoSet">设备信息集合句柄</param>
        /// <param name="dwIndex">元素索引</param>
        /// <param name="devInfoData">表示一个设备（作为输出）</param>
        /// <returns>是否成功</returns>
        [DllImport("setupapi.dll", SetLastError = true)]
        public static extern bool SetupDiEnumDeviceInfo(IntPtr lpInfoSet, UInt32 dwIndex, SP_DEVINFO_DATA devInfoData);


// <summary>
        /// 获取指定设备的属性
        /// </summary>
        /// <param name="lpInfoSet">设备信息集合</param>
        /// <param name="DeviceInfoData">表示该设备</param>
        /// <param name="Property">表示要获取哪项属性</param>
        /// <param name="PropertyRegDataType">注册类型</param>
        /// <param name="PropertyBuffer">属性（输出）</param>
        /// <param name="PropertyBufferSize">存储属性的字节大小</param>
        /// <param name="RequiredSize">需要的字节大小</param>
        /// <returns>是否成功</returns>
        [DllImport("setupapi.dll", SetLastError = true)]
        public static extern bool SetupDiGetDeviceRegistryProperty(IntPtr lpInfoSet, 
                                    SP_DEVINFO_DATA DeviceInfoData, 
                                    UInt32 Property, 
                                    UInt32 PropertyRegDataType, 
                                    StringBuilder PropertyBuffer, 
                                    UInt32 PropertyBufferSize, 
                                    IntPtr RequiredSize);

        /// <summary>
        /// 销毁一个设备信息集合，并且释放所有关联的内存
        /// </summary>
        /// <param name="lpInfoSet">设备信息集合</param>
        /// <returns></returns>
        [DllImport("setupapi.dll", SetLastError = true)]
        public static extern bool SetupDiDestroyDeviceInfoList(IntPtr lpInfoSet);
/// <summary>
        /// 设备信息数据
        /// </summary>
        [StructLayout(LayoutKind.Sequential)]
        public class SP_DEVINFO_DATA
        {
            public int cbSize;//本结构的大小（字节表示）
            public Guid classGuid;//本结构所表示的设备的GUID
            public int devInst;//设备句柄
            public ulong reserved;//没用
        };
    }
}
      如果大家想了解正则表达式的简单使用，推荐大家访问如下网址
http://www.szwblm.com/Netvb/ShowArticle.asp?ArticleID=19633，
http://www.szwblm.com/Netvb/ShowArticle.asp?ArticleID=14918

本文来自转载，小编尚未尝试，静待。。。