我尝试使用DeviceIoControl
函数(Win32 API函数)弹出我的CDROM驱动器,它在我的CDROM驱动器没有磁盘时工作正常,但在插入磁盘后,Marshal.GetLastWin32Error()
返回32 (ERROR_SHARING_VIOLATION
:进程无法访问该文件,因为它正由另一个进程使用),DeviceIoControl
中传递的driveHandle由CreateFile()
函数创建。
好的,这是代码:
using System;
using System.ComponentModel;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Runtime.InteropServices;
namespace DVD_ejector
{
public partial class Form1 : Form
{
const int OPENEXISTING = 3;
const int IOCTL_STORAGE_EJECT_MEDIA = 2967560;
const uint GENERICREAD = 0x80000000;
const int INVALID_HANDLE = -1;
public Form1()
{
InitializeComponent();
DriveInfo[] drs = DriveInfo.GetDrives();
List<DriveInfo> cdRoms = new List<DriveInfo>();
foreach (DriveInfo dInfo in drs)
{
if (dInfo.DriveType == DriveType.CDRom)
{
cdRoms.Add(dInfo);
}
}
comboBox1.DataSource = cdRoms;
comboBox1.DisplayMember = "Name";
if (comboBox1.Items.Count > 0) comboBox1.SelectedIndex = 0;
button1.Click += (sender, e) =>
{
Eject(@"\\.\" + ((DriveInfo)comboBox1.SelectedItem).Name[0]+":");
};
}
[DllImport("kernel32", SetLastError=true)]
static extern IntPtr CreateFile(string fileName, uint desiredAccess, uint shareMode, IntPtr attributes,uint creationDisposition, uint flagsAndAttribute, IntPtr fileTemplate);
[DllImport("kernel32")]
static extern int CloseHandle(IntPtr fileHandle);
[DllImport("kernel32")]
static extern bool DeviceIoControl(IntPtr driveHandle, int ctrlCode, IntPtr inBuffer, int inBufferSize, IntPtr outBuffer, int outBufferSize, ref int bytesReturned, IntPtr overlapped);
int bytesReturned;
private void Eject(string cdDrive)
{
IntPtr driveHandle = CreateFile(cdDrive, GENERICREAD, 0, IntPtr.Zero, OPENEXISTING, 0, IntPtr.Zero);
try
{
if((int)driveHandle != INVALID_HANDLE)
DeviceIoControl(driveHandle, IOCTL_STORAGE_EJECT_MEDIA, IntPtr.Zero, 0, IntPtr.Zero, 0, ref bytesReturned, IntPtr.Zero);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
finally
{
CloseHandle(driveHandle);
}
}
}
}
答案 0 :(得分:3)
正如错误所述,设备正在被其他设备使用,但它在CreateFile
调用而不是DeviceIoControl
上失败,并且您的代码未正确检查失败。
您获得共享冲突的原因是因为您尝试以独占方式打开设备,如果ANYTHING尝试打开它或其上的文件(包括反病毒,资源管理器,搜索索引器等),则会失败。
此更新的Eject
函数修复了共享模式和错误处理,现在可以在正确的位置报告错误。
private void Eject(string cdDrive) {
IntPtr driveHandle = new IntPtr(INVALID_HANDLE);
try {
// Open the device
driveHandle = CreateFile(cdDrive, GENERICREAD, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, IntPtr.Zero, OPENEXISTING, 0, IntPtr.Zero);
if ((int)driveHandle == INVALID_HANDLE) { throw new Win32Exception(); }
// Try and eject
bool ejected = DeviceIoControl(driveHandle, IOCTL_STORAGE_EJECT_MEDIA, IntPtr.Zero, 0, IntPtr.Zero, 0, ref bytesReturned, IntPtr.Zero);
if (!ejected) { throw new Win32Exception(); }
} catch (Exception ex) {
MessageBox.Show(ex.Message);
} finally {
if ((int)driveHandle != INVALID_HANDLE) { CloseHandle(driveHandle); }
}
}