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?


当前回答

在继续之前,检查一下你能控制的以下原因:

该文件夹是否设置为您的进程的当前目录?如果是,请先将其更改为其他内容。 您是否从该文件夹中打开了文件(或加载了DLL) ?(并且忘记关闭/卸载它)

否则,请检查以下不在你控制范围内的合理原因:

该文件夹中有标记为只读的文件。 您没有删除其中一些文件的权限。 文件或子文件夹在资源管理器或其他应用程序中打开。

如果是上述任何一个问题,在尝试改进删除代码之前,您应该了解为什么会发生这种情况。你的应用程序是否应该删除只读或不可访问的文件?是谁给它们做的标记,为什么?

一旦排除了上述原因,仍然存在虚假失败的可能性。如果任何人持有任何被删除的文件或文件夹的句柄,删除将失败,并且有人可能会枚举文件夹或读取其文件的原因有很多:

搜索索引器 要 备份软件

处理虚假失败的一般方法是尝试多次,在尝试之间暂停。显然,您不希望一直尝试下去,因此应该在一定次数的尝试后放弃,并抛出异常或忽略错误。是这样的:

private static void DeleteRecursivelyWithMagicDust(string destinationDir) {
    const int magicDust = 10;
    for (var gnomes = 1; gnomes <= magicDust; gnomes++) {
        try {
            Directory.Delete(destinationDir, true);
        } catch (DirectoryNotFoundException) {
            return;  // good!
        } catch (IOException) { // System.IO.IOException: The directory is not empty
            System.Diagnostics.Debug.WriteLine("Gnomes prevent deletion of {0}! Applying magic dust, attempt #{1}.", destinationDir, gnomes);

            // see http://stackoverflow.com/questions/329355/cannot-delete-directory-with-directory-deletepath-true for more magic
            Thread.Sleep(50);
            continue;
        }
        return;
    }
    // depending on your use case, consider throwing an exception here
}

在我看来,像这样的帮助器应该用于所有的删除,因为虚假的失败总是可能的。然而,你应该根据你的用例调整这些代码,而不是盲目地复制它。

我的应用程序生成的内部数据文件夹,位于%LocalAppData%下,所以我的分析如下:

The folder is controlled solely by my application, and the user has no valid reason to go and mark things as read-only or inaccessible inside that folder, so I don't try to handle that case. There's no valuable user-created stuff in there, so there's no risk of forcefully deleting something by mistake. Being an internal data folder, I don't expect it to be open in explorer, at least I don't feel the need to specifically handle the case (i.e. I'm fine handling that case via support). If all attempts fail, I choose to ignore the error. Worst case, the app fails to unpack some newer resources, crashes and prompts the user to contact support, which is acceptable to me as long as it does not happen often. Or, if the app does not crash, it will leave some old data behind, which again is acceptable to me. I choose to limit retries to 500ms (50 * 10). This is an arbitrary threshold which works in practice; I wanted the threshold to be short enough so that users wouldn't kill the app, thinking that it has stopped responding. On the other hand, half a second is plenty of time for the offender to finish processing my folder. Judging from other SO answers which sometimes find even Sleep(0) to be acceptable, very few users will ever experience more than a single retry. I retry every 50ms, which is another arbitrary number. I feel that if a file is being processed (indexed, checked) when I try to delete it, 50ms is about the right time to expect the processing to be completed in my case. Also, 50ms is small enough to not result in a noticeable slowdown; again, Sleep(0) seems to be enough in many cases, so we don't want to delay too much. The code retries on any IO exceptions. I don't normally expect any exceptions accessing %LocalAppData%, so I chose simplicity and accepted the risk of a 500ms delay in case a legitimate exception happens. I also didn't want to figure out a way to detect the exact exception that I want to retry on.

其他回答

你是否可能有一个竞争条件,另一个线程或进程正在向目录中添加文件:

顺序是:

删除进程A:

清空目录 删除(现在是空的)目录。

如果其他人在1和2之间添加了一个文件,那么2可能会抛出列出的异常?

有一件重要的事情需要提一下(我把它作为注释添加了进去,但是不允许我这样做),那就是重载的行为从。net 3.5改变到了。net 4.0。

Directory.Delete(myPath, true);

从。net 4.0开始,它会删除文件夹中的文件,但在3.5中不会。在MSDN文档中也可以看到这一点。

net 4.0

删除指定的目录,如果指定,删除该目录中的任何子目录和文件。

net 3.5

删除一个空目录,如果指定,删除目录中的任何子目录和文件。

我在特尔斐也遇到过同样的问题。最终的结果是我自己的应用程序锁定了我想要删除的目录。不知何故,当我写入目录(一些临时文件)时,目录被锁定了。

问题在于,在删除它之前,我对它的父目录做了一个简单的更改。

我有那些奇怪的权限问题删除用户配置文件目录(在C:\文档和设置),尽管能够这样做在资源管理器外壳。

File.SetAttributes(target_dir, FileAttributes.Normal);
Directory.Delete(target_dir, false);

对我来说,“文件”操作在目录上做什么毫无意义,但我知道它可以工作,这对我来说就足够了!

你不必创建一个额外的递归方法或删除额外文件夹内的文件。这些都是通过调用自动完成的

DirectoryInfo.Delete ();

详情在这里。

像这样的东西效果很好:

  var directoryInfo = new DirectoryInfo("My directory path");
    // Delete all files from app data directory.

    foreach (var subDirectory in directoryInfo.GetDirectories())
    {
          subDirectory.Delete(true);// true set recursive paramter, when it is true delete sub file and sub folder with files too
    }

将true作为变量传递给delete方法,将删除包含文件的子文件和子文件夹。