u盘插上会被识别(下面switch下有两个case做了操作,u盘插上电脑偶尔被识别U盘插入但偶尔也会被识别为一种设备插入,所以需要两种情况都判断),并检查其中含有指定文件,不含则被移除。

#region 设置指定u盘识别
        string strCurUsb = "";
        private bool bMonitorFlag = true;
        public const int WM_DEVICECHANGE = 0x219;//U盘插入后,OS的底层会自动检测到,然后向应用程序发送“硬件设备状态改变“的消息
        public const int DBT_DEVICEARRIVAL = 0x8000;  //就是用来表示U盘可用的。一个设备或媒体已被插入一块,现在可用。
        public const int DBT_CONFIGCHANGECANCELED = 0x0019;  //要求更改当前的配置(或取消停靠码头)已被取消。
        public const int DBT_CONFIGCHANGED = 0x0018;  //当前的配置发生了变化,由于码头或取消固定。
        public const int DBT_CUSTOMEVENT = 0x8006; //自定义的事件发生。 的Windows NT 4.0和Windows 95:此值不支持。
        public const int DBT_DEVICEQUERYREMOVE = 0x8001;  //审批要求删除一个设备或媒体作品。任何应用程序也不能否认这一要求,并取消删除。
        public const int DBT_DEVICEQUERYREMOVEFAILED = 0x8002;  //请求删除一个设备或媒体片已被取消。
        public const int DBT_DEVICEREMOVECOMPLETE = 0x8004;  //一个设备或媒体片已被删除。
        public const int DBT_DEVICEREMOVEPENDING = 0x8003;  //一个设备或媒体一块即将被删除。不能否认的。
        public const int DBT_DEVICETYPESPECIFIC = 0x8005;  //一个设备特定事件发生。
        public const int DBT_DEVNODES_CHANGED = 0x0007;  //一种设备已被添加到或从系统中删除。
        public const int DBT_QUERYCHANGECONFIG = 0x0017;  //许可是要求改变目前的配置(码头或取消固定)。
        public const int DBT_USERDEFINED = 0xFFFF;  //此消息的含义是用户定义的
        public const uint GENERIC_READ = 0x80000000;
        public const int GENERIC_WRITE = 0x40000000;
        public const int FILE_SHARE_READ = 0x1;
        public const int FILE_SHARE_WRITE = 0x2;
        public const int IOCTL_STORAGE_EJECT_MEDIA = 0x2d4808;

        private bool IsRemove(string Name)
        {
            string path = Name + "\\DCIM\\100MEDIA\\info.dat";
            if (File.Exists(path))
            {
                //string text = System.IO.File.ReadAllText(path);
                //FileInfo fi = new FileInfo(path);
                //string CreationTime = fi.CreationTime.ToString();
                //if (text == CreationTime)
                //    return false;
                //else
                //    return
                     return false;
            }
            else
                return true;
        }


        [DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
        private static extern IntPtr CreateFile(
         string lpFileName,
         uint dwDesireAccess,
         uint dwShareMode,
         IntPtr SecurityAttributes,
         uint dwCreationDisposition,
         uint dwFlagsAndAttributes,
         IntPtr hTemplateFile);

        [DllImport("kernel32.dll", ExactSpelling = true, SetLastError = true, CharSet = CharSet.Auto)]
        private static extern bool DeviceIoControl(
            IntPtr hDevice,
            uint dwIoControlCode,
            IntPtr lpInBuffer,
            uint nInBufferSize,
            IntPtr lpOutBuffer,
            uint nOutBufferSize,
            out uint lpBytesReturned,
            IntPtr lpOverlapped
        );


        /// <summary>
        /// 卸载当前指定的U盘存储设备
        /// </summary>
        /// <returns>卸载结果</returns>
        private bool RemoveUsbDevice()
        {
            //第一个参数filename与普通文件名有所不同,设备驱动的“文件名”(常称为“设备路径”)形式固定为“\\.\DeviceName”, 如 string filename = @"\\.\I:";
            string filename = @"\\.\" + strCurUsb.Remove(2);
            //打开设备,得到设备的句柄handle.
            IntPtr handle = CreateFile(filename, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, IntPtr.Zero, 0x3, 0, IntPtr.Zero);

            // 向目标设备发送设备控制码,也就是发送命令。IOCTL_STORAGE_EJECT_MEDIA  弹出U盘。
            uint byteReturned;
            bool result = DeviceIoControl(handle, IOCTL_STORAGE_EJECT_MEDIA, IntPtr.Zero, 0, IntPtr.Zero, 0, out byteReturned, IntPtr.Zero);

            //  MessageBox.Show(result ? "U盘已退出" : "U盘退出失败");
            return result;
        }


        protected override void WndProc(ref Message m)
        {
            if (bMonitorFlag)
            {
                try
                {
                    if (m.Msg == WM_DEVICECHANGE)
                    {
                        int x = m.WParam.ToInt32();
                        switch (m.WParam.ToInt32())
                        {
                            case DBT_DEVICEARRIVAL:
                                DriveInfo[] s = DriveInfo.GetDrives();
                                foreach (var t in s)
                                {

                                    if (t.DriveType == DriveType.Removable)
                                    {
                                        strCurUsb = t.Name;
                                        // MessageBox.Show("U盘插入,盘符为:" + t.Name);
                                        // DirSearch(t.RootDirectory.FullName);
                                        //TigMessage("U盘插入,盘符为:" + t.Name);
                                        bool ISRemove = IsRemove(t.Name);

                                        if (ISRemove)
                                        {
                                            bool result = RemoveUsbDevice();
                                            // TigMessage(result ? "U盘已卸载" : "U盘卸载失败");
                                        }
                                    }
                                }
                                break;
                            case WM_DEVICECHANGE:
                                break;
                            case DBT_CONFIGCHANGECANCELED:
                                break;
                            case DBT_CONFIGCHANGED:
                                break;
                            case DBT_CUSTOMEVENT:
                                break;
                            case DBT_DEVICEQUERYREMOVE:
                                break;
                            case DBT_DEVICEQUERYREMOVEFAILED:
                                break;
                            case DBT_DEVICEREMOVECOMPLETE: //U盘卸载
                                break;
                            case DBT_DEVICEREMOVEPENDING:
                                break;
                            case DBT_DEVICETYPESPECIFIC:
                                break;
                            case DBT_DEVNODES_CHANGED:
                                DriveInfo[] Dc = DriveInfo.GetDrives();
                                foreach (var t in Dc)
                                {
                                    if (t.DriveType == DriveType.Removable)
                                    {
                                        strCurUsb = t.Name;
                                        // MessageBox.Show("U盘插入,盘符为:" + t.Name);
                                        // DirSearch(t.RootDirectory.FullName);
                                        //TigMessage("U盘插入,盘符为:" + t.Name);
                                        bool ISRemove = IsRemove(t.Name);

                                        if (ISRemove)
                                        {
                                            bool result = RemoveUsbDevice();
                                            // TigMessage(result ? "U盘已卸载" : "U盘卸载失败");
                                        }
                                    }   
                                }
                                break;
                            case DBT_QUERYCHANGECONFIG:
                                break;
                            case DBT_USERDEFINED:
                                break;
                            default:
                                break;
                        }
                    }
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
            }
            base.WndProc(ref m);
        }
        #endregion