Programmatic Refresh of a File System

        /// <summary>
        /// Changed for C# and to allow for network drive types.
        /// </summary>
        /// <param name="localDrive"></param>
        public static void RefreshDrive(string localDrive)
        {
            DEV_BROADCAST_VOLUME hdr = new DEV_BROADCAST_VOLUME();
 
            // collect and clean the passed LocalDrive param
            if (localDrive == null || localDrive.Length == 0)
                throw new System.Exception("Invalid 'localDrive' passed, 'localDrive' parameter cannot be 'empty'");
            char drive = localDrive[0];
            long result;
 
            hdr.dbcv_size = (uint)Marshal.SizeOf(hdr);
            hdr.dbcv_devicetype = (uint)DevType.DBT_DEVTYP_NET;
            hdr.dbcv_reserved = 0;
            hdr.dbcv_unitmask = (uint) 1 << (drive - 'A');
            hdr.dbcv_flags = (ushort)Dbtf.DBTF_NET;
 
            IntPtr hdrp = Marshal.AllocHGlobal(Marshal.SizeOf(hdr));
            Marshal.StructureToPtr(hdr, hdrp, true);
            MessageBroadcastRecipients recip = MessageBroadcastRecipients.BSM_ALLCOMPONENTS;
 
            result = BroadcastSystemMessage(MessageBroadcastFlags.BSF_NOHANG | MessageBroadcastFlags.BSF_POSTMESSAGE,
                                   ref recip, WM_DEVICECHANGE, (IntPtr)DBT_DEVICEARRIVAL, hdrp);
 
            Marshal.FreeHGlobal(hdrp);
        }
 
        [DllImport("user32", SetLastError = true)]
        private static extern int BroadcastSystemMessage(MessageBroadcastFlags flags, ref MessageBroadcastRecipients lpInfo, uint Msg, IntPtr wParam, IntPtr lParam);
 
        const uint WM_DEVICECHANGE = 0x0219;
        const uint DBT_DEVICEARRIVAL = 0x8000;
 
        enum DevType : uint
        {
            DBT_DEVTYP_OEM = 0,
            DBT_DEVTYP_DEVNODE = 1,
            DBT_DEVTYP_VOLUME = 2,
            DBT_DEVTYP_PORT = 3,
            DBT_DEVTYP_NET = 4,
        }
        enum Dbtf : uint
        {
            DBTF_MEDIA = 0x0001,
            DBTF_NET = 0x0002,
        }
 
        [Flags]
        enum MessageBroadcastFlags : uint
        {
            BSF_QUERY = 0x00000001,
            BSF_IGNORECURRENTTASK = 0x00000002,
            BSF_FLUSHDISK = 0x00000004,
            BSF_NOHANG = 0x00000008,
            BSF_POSTMESSAGE = 0x00000010,
            BSF_FORCEIFHUNG = 0x00000020,
            BSF_NOTIMEOUTIFNOTHUNG = 0x00000040,
            BSF_ALLOWSFW = 0x00000080,
            BSF_SENDNOTIFYMESSAGE = 0x00000100,
            BSF_RETURNHDESK = 0x00000200,
            BSF_LUID = 0x00000400
        }
        [Flags]
        enum MessageBroadcastRecipients : uint
        {
            BSM_ALLCOMPONENTS = 0x00000000,
            BSM_VXDS = 0x00000001,
            BSM_NETDRIVER = 0x00000002,
            BSM_INSTALLABLEDRIVERS = 0x00000004,
            BSM_APPLICATIONS = 0x00000008,
            BSM_ALLDESKTOPS = 0x00000010
        }
 
        [StructLayout(LayoutKind.Sequential)]
        public struct DEV_BROADCAST_VOLUME
        {
            public uint dbcv_size;
            public uint dbcv_devicetype;
            public uint dbcv_reserved;
            public uint dbcv_unitmask;
            public ushort dbcv_flags;
        }

            // Unmap the existing drive, if it exists.
            UnmapDrive(Drive);
            NetworkDrive.RefreshDrive(Drive);
            Thread.Sleep(1000);
            MapDrive(Drive, uncpath);
            NetworkDrive.RefreshDrive(Drive);