我使用。net 3.5，试图递归删除目录使用:
Directory.Delete(myPath, true);
我的理解是，如果文件正在使用或存在权限问题，这应该抛出，但否则它应该删除目录及其所有内容。
然而，我偶尔会遇到这样的情况:
System.IO.IOException: The directory is not empty.
at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
at System.IO.Directory.DeleteHelper(String fullPath, String userPath, Boolean recursive)
at System.IO.Directory.Delete(String fullPath, String userPath, Boolean recursive)
...
我并不惊讶于这个方法有时会抛出错误，但我惊讶于当递归为真时得到这个特定的消息。(我知道目录不是空的。)
是否有一个原因，我将看到这个而不是AccessViolationException?
不删除文件的递归目录删除当然是意外的。我的解决办法是:
public class IOUtils
{
public static void DeleteDirectory(string directory)
{
Directory.GetFiles(directory, "*", SearchOption.AllDirectories).ForEach(File.Delete);
Directory.Delete(directory, true);
}
}
我经历过这样做有帮助的案例，但一般来说，Directory。Delete在递归删除时删除目录中的文件，如msdn中所述。
作为Windows资源管理器的用户，我偶尔也会遇到这种不正常的行为:有时我无法删除文件夹(它认为荒谬的消息是“拒绝访问”)，但当我向下钻取并删除较低的项目时，我也可以删除上面的项目。所以我猜上面的代码处理的是操作系统异常——而不是基类库问题。
现代异步回答
公认的答案是完全错误的，它可能适用于某些人，因为从磁盘获取文件所花费的时间释放了锁定文件的任何东西。事实上，这是因为文件被其他进程/流/操作锁定了。其他答案使用Thread。Sleep (Yuck)在一段时间后重试删除目录。这个问题需要一个更现代的答案来重新审视。
public static async Task<bool> TryDeleteDirectory(
string directoryPath,
int maxRetries = 10,
int millisecondsDelay = 30)
{
if (directoryPath == null)
throw new ArgumentNullException(directoryPath);
if (maxRetries < 1)
throw new ArgumentOutOfRangeException(nameof(maxRetries));
if (millisecondsDelay < 1)
throw new ArgumentOutOfRangeException(nameof(millisecondsDelay));
for (int i = 0; i < maxRetries; ++i)
{
try
{
if (Directory.Exists(directoryPath))
{
Directory.Delete(directoryPath, true);
}
return true;
}
catch (IOException)
{
await Task.Delay(millisecondsDelay);
}
catch (UnauthorizedAccessException)
{
await Task.Delay(millisecondsDelay);
}
}
return false;
}
单元测试
这些测试展示了一个被锁定的文件如何导致目录的示例。删除失败以及上面的TryDeleteDirectory方法如何修复这个问题。
[Fact]
public async Task TryDeleteDirectory_FileLocked_DirectoryNotDeletedReturnsFalse()
{
var directoryPath = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString());
var subDirectoryPath = Path.Combine(Path.GetTempPath(), "SubDirectory");
var filePath = Path.Combine(directoryPath, "File.txt");
try
{
Directory.CreateDirectory(directoryPath);
Directory.CreateDirectory(subDirectoryPath);
using (var fileStream = new FileStream(filePath, FileMode.Create, FileAccess.Write, FileShare.Write))
{
var result = await TryDeleteDirectory(directoryPath, 3, 30);
Assert.False(result);
Assert.True(Directory.Exists(directoryPath));
}
}
finally
{
if (Directory.Exists(directoryPath))
{
Directory.Delete(directoryPath, true);
}
}
}
[Fact]
public async Task TryDeleteDirectory_FileLockedThenReleased_DirectoryDeletedReturnsTrue()
{
var directoryPath = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString());
var subDirectoryPath = Path.Combine(Path.GetTempPath(), "SubDirectory");
var filePath = Path.Combine(directoryPath, "File.txt");
try
{
Directory.CreateDirectory(directoryPath);
Directory.CreateDirectory(subDirectoryPath);
Task<bool> task;
using (var fileStream = new FileStream(filePath, FileMode.Create, FileAccess.Write, FileShare.Write))
{
task = TryDeleteDirectory(directoryPath, 3, 30);
await Task.Delay(30);
Assert.True(Directory.Exists(directoryPath));
}
var result = await task;
Assert.True(result);
Assert.False(Directory.Exists(directoryPath));
}
finally
{
if (Directory.Exists(directoryPath))
{
Directory.Delete(directoryPath, true);
}
}
}
我花了几个小时来解决这个问题和删除目录的其他异常。
这就是我的解
public static void DeleteDirectory(string target_dir)
{
DeleteDirectoryFiles(target_dir);
while (Directory.Exists(target_dir))
{
lock (_lock)
{
DeleteDirectoryDirs(target_dir);
}
}
}
private static void DeleteDirectoryDirs(string target_dir)
{
System.Threading.Thread.Sleep(100);
if (Directory.Exists(target_dir))
{
string[] dirs = Directory.GetDirectories(target_dir);
if (dirs.Length == 0)
Directory.Delete(target_dir, false);
else
foreach (string dir in dirs)
DeleteDirectoryDirs(dir);
}
}
private static void DeleteDirectoryFiles(string target_dir)
{
string[] files = Directory.GetFiles(target_dir);
string[] dirs = Directory.GetDirectories(target_dir);
foreach (string file in files)
{
File.SetAttributes(file, FileAttributes.Normal);
File.Delete(file);
}
foreach (string dir in dirs)
{
DeleteDirectoryFiles(dir);
}
}
这段代码有很小的延迟，这对我的应用程序并不重要。但是要注意，如果要删除的目录中有很多子目录，那么延迟可能会成为一个问题。
这个答案基于:https://stackoverflow.com/a/1703799/184528。与我的代码不同的是，我们只递归许多删除子目录和文件时，需要调用目录。第一次尝试删除失败(这可能是因为windows资源管理器查看目录)。
public static void DeleteDirectory(string dir, bool secondAttempt = false)
{
// If this is a second try, we are going to manually
// delete the files and sub-directories.
if (secondAttempt)
{
// Interrupt the current thread to allow Explorer time to release a directory handle
Thread.Sleep(0);
// Delete any files in the directory
foreach (var f in Directory.GetFiles(dir, "*.*", SearchOption.TopDirectoryOnly))
File.Delete(f);
// Try manually recursing and deleting sub-directories
foreach (var d in Directory.GetDirectories(dir))
DeleteDirectory(d);
// Now we try to delete the current directory
Directory.Delete(dir, false);
return;
}
try
{
// First attempt: use the standard MSDN approach.
// This will throw an exception a directory is open in explorer
Directory.Delete(dir, true);
}
catch (IOException)
{
// Try again to delete the directory manually recursing.
DeleteDirectory(dir, true);
}
catch (UnauthorizedAccessException)
{
// Try again to delete the directory manually recursing.
DeleteDirectory(dir, true);
}
}
