C#でUSBメモリの安全な取り外しがしたい

Question

前提・実現したいこと

WPFを用いてUSBメモリの取り外しを行いたいと思っています。
取り外しはできているようなのですが、下記のコードで確認するとドライブが残っています。

Directory.GetLogicalDrives()

完全な取り外しはできないでしょうか？

MainWindow.xaml

        private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            USB lusb = new USB();
            lusb.Eject("D");
        }

USB.cs

using System;

using System.Runtime.InteropServices;
using System.Threading;
using System.Windows;

namespace test1_wpf
{
    class USB
    {

        [DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
        private static extern IntPtr CreateFile(
          string lpFileName,
          uint dwDesiredAccess,
          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
        );

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

        [DllImport("kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool CloseHandle(IntPtr hObject);

        private IntPtr handle = IntPtr.Zero;

        const uint GENERIC_READ = 0x80000000;
        const uint GENERIC_WRITE = 0x40000000;
        const int FILE_SHARE_READ = 0x1;
        const int FILE_SHARE_WRITE = 0x2;
        const int FSCTL_LOCK_VOLUME = 0x00090018;
        const int FSCTL_DISMOUNT_VOLUME = 0x00090020;
        const int IOCTL_STORAGE_EJECT_MEDIA = 0x2D4808;
        const int IOCTL_STORAGE_MEDIA_REMOVAL = 0x002D4804;

        public IntPtr USBEject(string driveLetter)
        {
            string filename = @"\.\" + driveLetter[0] + ":";
            return CreateFile(filename, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, IntPtr.Zero, 0x3, 0, IntPtr.Zero);
        }

        public bool Eject(IntPtr handle)
        {
            bool result = false;

            if (LockVolume(handle) && DismountVolume(handle))
            {
                PreventRemovalOfVolume(handle, false);
                result = AutoEjectVolume(handle);
            }
            CloseHandle(handle);
            return result;
        }

        private bool LockVolume(IntPtr handle)
        {
            uint byteReturned;

            for (int i = 0; i < 10; i++)
            {
                if (DeviceIoControl(handle, FSCTL_LOCK_VOLUME, IntPtr.Zero, 0, IntPtr.Zero, 0, out byteReturned, IntPtr.Zero))
                {
                    MessageBox.Show("Lock success!");
                    return true;
                }
                Thread.Sleep(500);
            }
            return false;
        }

        private bool PreventRemovalOfVolume(IntPtr handle, bool prevent)
        {
            byte[] buf = new byte[1];
            uint retVal;

            buf[0] = (prevent) ? (byte)1 : (byte)0;
            return DeviceIoControl(handle, IOCTL_STORAGE_MEDIA_REMOVAL, buf, 1, IntPtr.Zero, 0, out retVal, IntPtr.Zero);
        }

        private bool DismountVolume(IntPtr handle)
        {
            uint byteReturned;
            return DeviceIoControl(handle, FSCTL_DISMOUNT_VOLUME, IntPtr.Zero, 0, IntPtr.Zero, 0, out byteReturned, IntPtr.Zero);
        }

        private bool AutoEjectVolume(IntPtr handle)
        {
            uint byteReturned;
            return DeviceIoControl(handle, IOCTL_STORAGE_EJECT_MEDIA, IntPtr.Zero, 0, IntPtr.Zero, 0, out byteReturned, IntPtr.Zero);
        }

        private bool CloseVolume(IntPtr handle)
        {
            return CloseHandle(handle);
        }


        public void EjectDrive(char driveLetter)
        {
            string path = @"\.\" + driveLetter + @":";
            IntPtr handle = CreateFile(path, GENERIC_READ | GENERIC_WRITE,
            FILE_SHARE_READ | FILE_SHARE_WRITE, IntPtr.Zero, 0x3, 0, IntPtr.Zero);

            if ((long)handle == -1)
            {
                MessageBox.Show("Unable to open drive " + driveLetter);
                return;
            }

            uint dummy = 0;

            DeviceIoControl(handle, IOCTL_STORAGE_EJECT_MEDIA, IntPtr.Zero, 0,
                IntPtr.Zero, 0, out dummy, IntPtr.Zero);

            CloseHandle(handle);

            MessageBox.Show("OK to remove drive.");
        }
    }
}

補足情報（FW/ツールのバージョンなど）

Windows 10 Pro
Visual Studio 2017
.NetFramework 4.0

• 実行前

• 実行後

Answer 1

CM_Request_Device_Ejectを利用されてみてはどうでしょうか？
こちらやこちらとか参考になりませんか？

Comments

[退会済みユーザー]

参考URLありがとうございます。

```C#
enum PNP_VETO_TYPE : int
{
PNP_VetoTypeUnknown = 0,
PNP_VetoLegacyDevice = 1,
PNP_VetoPendingClose = 2,
PNP_VetoWindowsApp = 3,
PNP_VetoWindowsService = 4,
PNP_VetoOutstandingOpen = 5,
PNP_VetoDevice = 6,
PNP_VetoDriver = 7,
PNP_VetoIllegalDeviceRequest = 8,
PNP_VetoInsufficientPower = 9,
PNP_VetoNonDisableable = 10,
PNP_VetoLegacyDriver = 11,
PNP_VetoInsufficientRights = 12
}

[DllImport("setupapi.dll", CharSet = CharSet.Auto)]
static extern int CM_Request_Device_Eject(
UInt32 devinst, out PNP_VETO_TYPE pVetoType,
System.Text.StringBuilder pszVetoName,
int ulNameLength,
int ulFlags
);

・・・

CM_Request_Device_Eject((uint)devinst, out pnp_veto_type, sb, sb.Capacity, 0);
```
安直に、CreateFileで生成したIntPtrを入れても動作しないようです。。。
参考サイトを正しく認識できていない点が大きいとは思いますが。

[YAmaGNZ]

CreateFileにて得られたハンドルを使用することはできません。
https://www.codeproject.com/Articles/375916/How-to-Prepare-a-USB-Drive-for-Safe-Removal-2
こちらにもっと分かりやすいサンプルがありましたので、参照してみてください。

[退会済みユーザー]

ありがとうございます！ご提示いただいたサイトを参考に問題なく動きました！
これを自力で実装はほぼ不可能に近いので大変助かりました！