我一直在寻找一种通过 C# 代码弹出 USB 设备的简便方法，所以我自己编写了一个小类，但它根本不起作用。由于没有弹出窗口显示“锁定成功!”我假设问题出在“LockVolume”函数中，但我不知道出在哪里。

有人看到我犯的错误吗？

class USBEject
{
    [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 int GENERIC_READ = 0x80000000;
    const int 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;

    /// <summary>
    /// Constructor for the USBEject class
    /// </summary>
    /// <param name="driveLetter">This should be the drive letter. Format: F:/, C:/..</param>

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

    public bool Eject()
    {
        if (LockVolume(handle) && DismountVolume(handle))
        {
            PreventRemovalOfVolume(handle, false);
            return AutoEjectVolume(handle);
        }

        return false;
    }

    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))
            {
                System.Windows.Forms.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);
    }
}

最佳答案

稍微更改了您的代码，如下所示:

    [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;

    /// <summary>
    /// Constructor for the USBEject class
    /// </summary>
    /// <param name="driveLetter">This should be the drive letter. Format: F:/, C:/..</param>

    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))
            {
                System.Windows.Forms.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);
    }

因此您可以通过两种方式使用它:

        handle = USBEject("D:");
        Eject(handle);

或直接:

        Eject(USBEject("D:"));

它适用于我的 Windows 10 机器(预览版 14291)

关于c# - 通过 C# 弹出 USB 设备，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/7704599/