如何使用C＃同步和一致地刪除NTFS上的文件夾

Question

這個：

Directory.Delete(dir, true);

不是同步的。

在緊接着的行中，您仍然可以操作/讀取目錄。

例如，這個：

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

導致文件夾不存在。 刪除運行異步， CreateDirectory不創建，因為它已經存在，然后刪除實際觸發並刪除目錄。

是否有一個IO API可以提供一致性？

涉及Thread.Sleep答案將調用Zalgo。 我想要一個真正的解決方案。

Answer 1

正如其他人所提到的那樣，.net Framework似乎並沒有同步運行它。 在PowerShell中測試它表明.Net調用不會等待，所以這樣的事情會產生類似的結果：

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

使用文件觀察器（前面也提到過）將確保在創建完成之前完成目錄刪除：

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

沒有真正意外，但至少它是一個有效的解決方案，不涉及從托管代碼調用C ++ API。

Answer 2

這是一個有相同問題的人的鏈接 ，首先重命名/移動目錄的解決方案可能適合您。

否則你可以使用FileWatcher來對目錄刪除作出反應，但這感覺就像是矯枉過正。

Answer 3

在C ++中進行一些測試后，似乎用於刪除文件/目錄的本機Windows功能會阻塞。 當刪除函數未被阻止時，似乎問題出現在.NET端，因為Directory.CreateDirectory()似乎在Directory.Delete()完成之前被調用。

這是我在Win32控制台應用程序中嘗試的：

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，在顯示結果之前會有一個小的延遲，然后在查看文件夾后，它會為空，帶有新的創建和最后修改日期 - 這意味着它已被刪除並以正確的順序重新創建。

所以為了實現你想要的，我想你可以嘗試創建自己的方法來調用SHFileOperation() ，因為問題似乎是Directory.Delete()方法在.NET代碼中執行迭代（參見參考資料來源 ）。

---

---編輯---

在C＃中測試后，這似乎有效！ 唯一的問題是，第一次（自應用程序啟動以來）調用P / Invoked SHFileOperation()函數，它將返回值2，這相當於ERROR_FILE_NOT_FOUND 。 但如果再次執行它將返回0（成功）。

NativeMethods.cs：

需要進口：

using System;
using System.Runtime.InteropServices;

其余代碼：

[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);

希望這可以幫助！