控制usb的问题
我想使用CreateFile和WriteFile来控制usb口的针式打印机，用SetupDi系列方法来找到打印机端口，但却只能找到USB键盘及鼠标，U盘或者打印机都找不到，请问这是什么原因？我的代码如下，是C#的代码
using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Text;using System.Windows.Forms;using System.Runtime.InteropServices;using System.Threading;using System.Collections;using System.IO;namespace USB{ class Class1 { //以下是调用windows的API的函数 //获得GUID [DllImport("hid.dll")] public static extern void HidD_GetHidGuid(ref Guid HidGuid); Guid guidHID = Guid.Empty; //过滤设备，获取需要的设备 [DllImport("setupapi.dll", SetLastError = true)] public static extern IntPtr SetupDiGetClassDevs(ref Guid ClassGuid, uint Enumerator, IntPtr HwndParent, DIGCF Flags); IntPtr hDevInfo; //获取设备，true获取到 [DllImport("setupapi.dll", CharSet = CharSet.Auto, SetLastError = true)] public static extern Boolean SetupDiEnumDeviceInterfaces(IntPtr hDevInfo, IntPtr devInfo, ref Guid interfaceClassGuid, UInt32 memberIndex, ref SP_DEVICE_INTERFACE_DATA deviceInterfaceData); public struct SP_DEVICE_INTERFACE_DATA { public int cbSize; public Guid interfaceClassGuid; public int flags; public int reserved; } [StructLayout(LayoutKind.Sequential)] private struct OVERLAPPED { int Internal; int InternalHigh; int Offset; int OffSetHigh; int hEvent; } // 获取接口的详细信息 必须调用两次 第1次返回长度 第2次获取数据 [DllImport("setupapi.dll", SetLastError = true, CharSet = CharSet.Auto)] private static extern bool SetupDiGetDeviceInterfaceDetail(IntPtr deviceInfoSet, ref SP_DEVICE_INTERFACE_DATA deviceInterfaceData, IntPtrdeviceInterfaceDetailData, int deviceInterfaceDetailDataSize, ref int requiredSize, SP_DEVINFO_DATA deviceInfoData); [StructLayout(LayoutKind.Sequential)] public class SP_DEVINFO_DATA { public int cbSize = Marshal.SizeOf(typeof(SP_DEVINFO_DATA)); public Guid classGuid = Guid.Empty; // temp public int devInst = 0; // dumy public int reserved = 0; } [StructLayout(LayoutKind.Sequential, Pack = 2)] internal struct SP_DEVICE_INTERFACE_DETAIL_DATA { internal int cbSize; internal short devicePath; } public enum DIGCF { DIGCF_DEFAULT = 0x1, DIGCF_PRESENT = 0x2, DIGCF_ALLCLASSES = 0x4, DIGCF_PROFILE = 0x8, DIGCF_DEVICEINTERFACE = 0x10 } //获取设备文件 [DllImport("kernel32.dll", SetLastError = true)] private static extern int CreateFile( string lpFileName, // file name uint dwDesiredAccess, // access mode uint dwShareMode, // share mode uint lpSecurityAttributes, // SD uint dwCreationDisposition, // how to create uint dwFlagsAndAttributes, // file attributes uint hTemplateFile // handle to template file ); //读取设备文件 [DllImport("Kernel32.dll", SetLastError = true)] private static extern bool ReadFile ( IntPtr hFile, byte[] lpBuffer, uint nNumberOfBytesToRead, ref uint lpNumberOfBytesRead, IntPtr lpOverlapped ); [DllImport("kernel32.dll")] private static extern bool WriteFile ( int hFile, byte[] lpBuffer, int nNumberOfBytesToWriter, out int lpNumberOfBytesWriten, out OVERLAPPED lpOverLapped ); //释放设备 [DllImport("hid.dll")] static public extern bool HidD_FreePreparsedData(ref IntPtr PreparsedData); //关闭访问设备句柄，结束进程的时候把这个加上保险点 [DllImport("kernel32.dll")] static public extern int CloseHandle(int hObject); int HidHandle = -1; public const uint GENERIC_READ = 0x80000000; public const uint GENERIC_WRITE = 0x40000000; public const uint FILE_SHARE_READ = 0x00000001; public const uint FILE_SHARE_WRITE = 0x00000002; public const int OPEN_EXISTING = 3; public void UsBMethod(int index) { HidD_GetHidGuid(ref guidHID); //此处获得的guidHID就是所有usb的HID吗？？？ hDevInfo = SetupDiGetClassDevs(ref guidHID, 0, IntPtr.Zero, DIGCF.DIGCF_PRESENT | DIGCF.DIGCF_DEVICEINTERFACE); int bufferSize = 0; ArrayList HIDUSBAddress = new ArrayList(); string devicePathName = ""; while (true) { //获取设备，true获取到 SP_DEVICE_INTERFACE_DATA DeviceInterfaceData = new SP_DEVICE_INTERFACE_DATA(); DeviceInterfaceData.cbSize = Marshal.SizeOf(DeviceInterfaceData); bool result = false; //for (int i = 0; i < 3; i++) //{ result = SetupDiEnumDeviceInterfaces(hDevInfo, IntPtr.Zero, ref guidHID, (UInt32)index, ref DeviceInterfaceData); int b = Marshal.GetLastWin32Error(); //} //第一次调用出错，但可以返回正确的Size SP_DEVINFO_DATA strtInterfaceData = new SP_DEVINFO_DATA(); result = SetupDiGetDeviceInterfaceDetail(hDevInfo, ref DeviceInterfaceData, IntPtr.Zero, 0, ref bufferSize, strtInterfaceData); //第二次调用传递返回值，调用即可成功 IntPtr detailDataBuffer = Marshal.AllocHGlobal(bufferSize); SP_DEVICE_INTERFACE_DETAIL_DATA detailData = new SP_DEVICE_INTERFACE_DETAIL_DATA(); detailData.cbSize = Marshal.SizeOf(typeof(SP_DEVICE_INTERFACE_DETAIL_DATA)); Marshal.StructureToPtr(detailData, detailDataBuffer, false); result = SetupDiGetDeviceInterfaceDetail(hDevInfo, ref DeviceInterfaceData, detailDataBuffer, bufferSize, ref bufferSize, strtInterfaceData); if (result == false) { break; } //获取设备路径访 IntPtr pdevicePathName = (IntPtr)((int)detailDataBuffer + 4); devicePathName = Marshal.PtrToStringAuto(pdevicePathName); HIDUSBAddress.Add(devicePathName); index++; } //连接设备文件 int aa = CT_CreateFile(devicePathName); } //建立和设备的连接 public int CT_CreateFile(string DeviceName) { HidHandle = CreateFile( DeviceName, GENERIC_READ | GENERIC_WRITE,//读写，或者一起 0,// | FILE_SHARE_WRITE,//共享读写，或者一起 0, OPEN_EXISTING, 0, 0); int a = Marshal.GetLastWin32Error(); if (HidHandle == -1) { return 0; } else { return 1; } } }}