如何使用C＃同步和一致地删除NTFS上的文件夹

Question

这个：

Directory.Delete(dir, true);

不是同步的。

在紧接着的行中，您仍然可以操作/读取目录。

例如，这个：

Directory.Delete(destinationDir, true);
Directory.CreateDirectory(destinationDir);
Thread.Sleep(1000);

导致文件夹不存在。 删除运行异步， CreateDirectory不创建，因为它已经存在，然后删除实际触发并删除目录。

是否有一个IO API可以提供一致性？

涉及Thread.Sleep答案将调用Zalgo。 我想要一个真正的解决方案。

Answer 1

正如其他人所提到的那样，.net Framework似乎并没有同步运行它。 在PowerShell中测试它表明.Net调用不会等待，所以这样的事情会产生类似的结果：

Remove-Item -Recurse -Force "C:\tempfolder"
New-Item -ItemType Directory "C:\tempfolder"

使用文件观察器（前面也提到过）将确保在创建完成之前完成目录删除：

var path = @"C:\tempfolder";
var watcher = new FileSystemWatcher(path);
watcher.Deleted += (sender, args) => Directory.CreateDirectory(args.FullPath);
Directory.Delete(path, true);

没有真正意外，但至少它是一个有效的解决方案，不涉及从托管代码调用C ++ API。

Answer 2

这是一个有相同问题的人的链接 ，首先重命名/移动目录的解决方案可能适合您。

否则你可以使用FileWatcher来对目录删除作出反应，但这感觉就像是矫枉过正。

Answer 3

在C ++中进行一些测试后，似乎用于删除文件/目录的本机Windows功能会阻塞。 当删除函数未被阻止时，似乎问题出现在.NET端，因为Directory.CreateDirectory()似乎在Directory.Delete()完成之前被调用。

这是我在Win32控制台应用程序中尝试的：

printf("Press enter to begin...");
while(getchar() != '\n');

LPCSTR DeletePath = "C:\\test\\DeleteMe"; //The directory to delete.
_SHFILEOPSTRUCTA* fileopt = new _SHFILEOPSTRUCTA();

fileopt->hwnd = NULL;        //No window handle.
fileopt->wFunc = FO_DELETE;  //Delete mode.
fileopt->pFrom = DeletePath; //The directory to delete.
fileopt->pTo = NULL;         //No target directory (this is only used when moving, copying, etc.).
fileopt->fFlags = FOF_NO_UI; //Display no UI dialogs.

int Success = SHFileOperationA(fileopt); //Remove the entire directory and all it's contents.
bool Success2 = CreateDirectoryA(DeletePath, NULL); //Create a new directory.

LPCSTR ReturnedValue = "False"; //I'm no C++ guru, so please don't hate. :)
LPCSTR ReturnedValue2 = "False";
if(Success == 0) { ReturnedValue = "True"; } //The SHFileOperation() returns 0 if it succeeds.
if(Success2 == true) { ReturnedValue2 = "True"; }

//Print the result of SHFileOperation().
printf("Returned value: ");
printf(ReturnedValue);
printf("\n");

//Print the result of CreateDirectory().
printf("Returned value 2: ");
printf(ReturnedValue2);
printf("\n");

//Continue.
printf("Press enter to exit...");
while(getchar() != '\n');

在第一次按下ENTER之后，在显示结果之前会有一个小的延迟，然后在查看文件夹后，它会为空，带有新的创建和最后修改日期 - 这意味着它已被删除并以正确的顺序重新创建。

所以为了实现你想要的，我想你可以尝试创建自己的方法来调用SHFileOperation() ，因为问题似乎是Directory.Delete()方法在.NET代码中执行迭代（参见参考资料来源 ）。

---

---编辑---

在C＃中测试后，这似乎有效！ 唯一的问题是，第一次（自应用程序启动以来）调用P / Invoked SHFileOperation()函数，它将返回值2，这相当于ERROR_FILE_NOT_FOUND 。 但如果再次执行它将返回0（成功）。

NativeMethods.cs：

需要进口：

using System;
using System.Runtime.InteropServices;

其余代码：

[DllImport("shell32.dll", CharSet = CharSet.Unicode)]
public static extern int SHFileOperation([In] ref SHFILEOPSTRUCT lpFileOp);

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct SHFILEOPSTRUCT
{
    public IntPtr hwnd;
    public FileFuncFlags wFunc;

    [MarshalAs(UnmanagedType.LPWStr)]
    public string pFrom;

    [MarshalAs(UnmanagedType.LPWStr)]
    public string pTo;
    public FILEOP_FLAGS fFlags;

    [MarshalAs(UnmanagedType.Bool)]
    public bool fAnyOperationsAborted;
    public IntPtr hNameMappings;

    [MarshalAs(UnmanagedType.LPWStr)]
    public string lpszProgressTitle;
}

public enum FileFuncFlags : uint
{
    FO_MOVE = 0x1,
    FO_COPY = 0x2,
    FO_DELETE = 0x3,
    FO_RENAME = 0x4
}

[Flags]
public enum FILEOP_FLAGS : ushort
{
    FOF_MULTIDESTFILES = 0x1,
    FOF_CONFIRMMOUSE = 0x2,
    /// <summary>
    /// Don't create progress/report
    /// </summary>
    FOF_SILENT = 0x4,
    FOF_RENAMEONCOLLISION = 0x8,
    /// <summary>
    /// Don't prompt the user.
    /// </summary>
    FOF_NOCONFIRMATION = 0x10,
    /// <summary>
    /// Fill in SHFILEOPSTRUCT.hNameMappings.
    /// Must be freed using SHFreeNameMappings
    /// </summary>
    FOF_WANTMAPPINGHANDLE = 0x20,
    FOF_ALLOWUNDO = 0x40,
    /// <summary>
    /// On *.*, do only files
    /// </summary>
    FOF_FILESONLY = 0x80,
    /// <summary>
    /// Don't show names of files
    /// </summary>
    FOF_SIMPLEPROGRESS = 0x100,
    /// <summary>
    /// Don't confirm making any needed dirs
    /// </summary>
    FOF_NOCONFIRMMKDIR = 0x200,
    /// <summary>
    /// Don't put up error UI
    /// </summary>
    FOF_NOERRORUI = 0x400,
    /// <summary>
    /// Dont copy NT file Security Attributes
    /// </summary>
    FOF_NOCOPYSECURITYATTRIBS = 0x800,
    /// <summary>
    /// Don't recurse into directories.
    /// </summary>
    FOF_NORECURSION = 0x1000,
    /// <summary>
    /// Don't operate on connected elements.
    /// </summary>
    FOF_NO_CONNECTED_ELEMENTS = 0x2000,
    /// <summary>
    /// During delete operation, 
    /// warn if nuking instead of recycling (partially overrides FOF_NOCONFIRMATION)
    /// </summary>
    FOF_WANTNUKEWARNING = 0x4000,
    /// <summary>
    /// Treat reparse points as objects, not containers
    /// </summary>
    FOF_NORECURSEREPARSE = 0x8000
}

其他地方：

string DeletePath = "C:\\test\\DeleteMe";
NativeMethods.SHFILEOPSTRUCT fileopt = new NativeMethods.SHFILEOPSTRUCT();

fileopt.hwnd = IntPtr.Zero;
fileopt.wFunc = NativeMethods.FileFuncFlags.FO_DELETE;
fileopt.pFrom = DeletePath;
fileopt.pTo = null;
fileopt.fFlags = NativeMethods.FILEOP_FLAGS.FOF_SILENT | NativeMethods.FILEOP_FLAGS.FOF_NOCONFIRMATION |
                 NativeMethods.FILEOP_FLAGS.FOF_NOERRORUI | NativeMethods.FILEOP_FLAGS.FOF_NOCONFIRMMKDIR; //Equivalent of FOF_NO_UI.

int Success = NativeMethods.SHFileOperation(ref fileopt);
Directory.CreateDirectory(DeletePath);

MessageBox.Show("Operation returned value: " + Success.ToString(), "Test", MessageBoxButtons.OK, MessageBoxIcon.Information);

希望这可以帮助！