如何在遍历文件夹树时删除文件

Question

我不确定我这样做是否正确，或者我的逻辑是否正确。

我正在尝试向下文件夹结构删除超过一定天数的文件，这部分我已经正确实现，删除空文件夹。

所有这些都可以在一个循环中完成吗？
我在哪里删除文件夹？

我想删除最多 3 或 4 级以下的空文件夹。

    private static void TraverseTree(System.IO.DirectoryInfo folder, double days)
    {
        Stack<string> dirs = new Stack<string>();

        if (!folder.Exists)
            throw new ArgumentException();

        dirs.Push(folder.FullName);

        while (dirs.Count > 0)
        {
            string currentDir = dirs.Pop();
            string[] subDirs;
            try
            {
                subDirs = System.IO.Directory.GetDirectories(currentDir);
            }
            // An UnauthorizedAccessException exception will be thrown if we do not have
            // discovery permission on a folder or file. It may or may not be acceptable 
            // to ignore the exception and continue enumerating the remaining files and 
            // folders. It is also possible (but unlikely) that a DirectoryNotFound exception 
            // will be raised. This will happen if currentDir has been deleted by
            // another application or thread after our call to Directory.Exists. The 
            // choice of which exceptions to catch depends entirely on the specific task 
            // you are intending to perform and also on how much you know with certainty 
            // about the systems on which this code will run.
            catch (UnauthorizedAccessException e)
            {
                Console.WriteLine(e.Message);
                continue;
            }
            catch (System.IO.DirectoryNotFoundException e)
            {
                Console.WriteLine(e.Message);
                continue;
            }

            string[] files = null;
            try
            {
                files = System.IO.Directory.GetFiles(currentDir);
            }
            catch (UnauthorizedAccessException e)
            {

                Console.WriteLine(e.Message);
                continue;
            }
            catch (System.IO.DirectoryNotFoundException e)
            {
                Console.WriteLine(e.Message);
                continue;
            }

            // Perform the required action on each file here.
            // Modify this block to perform your required task.
            foreach (string file in files)
            {
                try
                {
                    // Perform whatever action is required in your scenario.
                    System.IO.FileInfo fi = new System.IO.FileInfo(file);
                    Console.WriteLine("{0}: {1}, {2}", fi.Name, fi.Length, fi.CreationTime);

                    // Delete old files
                    if (fi.LastWriteTime < DateTime.Now.AddDays(-days))
                        fi.Delete();
                }
                catch (System.IO.FileNotFoundException e)
                {
                    // If file was deleted by a separate application
                    //  or thread since the call to TraverseTree()
                    // then just continue.
                    Console.WriteLine(e.Message);
                    continue;
                }
            }

            // Push the subdirectories onto the stack for traversal.
            // This could also be done before handing the files.
            foreach (string str in subDirs)
                dirs.Push(str);
        }
    }

代码来自MSDN。

Answer 1

递归方法可能会更简洁。

private static void DeleteOldFilesAndFolders(string path)
{
    foreach (string directory in System.IO.Directory.GetDirectories(path))
    {
        DeleteOldFilesAndFolders(directory);

        // If the directory is empty and old, delete it here.
    }

    foreach (string file in System.IO.Directory.GetFiles(path))
    {
        // Check the file's age and delete it if it's old.
    }
}

Answer 2

我注意到您的代码的一点是，用于遍历树结构的数十行“机制”完全压倒了实际完成工作的两行代码。这使得代码难以阅读、理解、更改、调试和维护。

这就是我要做的。

您的程序中只有三个高级操作：(1) 获取所有文件，(2) 过滤以查找要删除的文件，(3) 删除每个文件。所以编写一个程序，在一个语句中完成所有这些。

对于第一个操作，我会将上述机制分解为它自己的函数：一个实现例如 IEnumerable 的函数，它所做的只是不断产生有关文件的信息。它对他们没有做任何事情；它的唯一目的是不断吐出文件信息。

一旦你有了这个机制，你就可以开始在这个序列之上编写查询来实现第二个操作。第三个操作紧接着第二个。

简而言之，你的程序的主线应该是这样的：

var allFiles = TraverseFolder(folder);
var filesToDelete = from file in allFiles where IsOld(file) select file;
foreach(var fileToDelete in filesToDelete) Delete(fileToDelete);

清楚吗？

Answer 3

这里几乎有同样的问题：

How to delete all files and folders in a directory?

这是按名称删除，但您可以检查其他属性。

Answer 4

Here is a more general solution 给你一个文件系统walker 以非递归方式实现为IEnumerable 的问题。

您的解决方案可能实现为：

List<string> directoriesToDelete = new List<string>();
DirectoryWalker walker = new DirectoryWalker(@"C:\pathToSource\src",
    dir => {
        if (Directory.GetFileSystemEntries(dir).Length == 0) {
            directoriesToDelete.Add(dir);
            return false;
        }
        return true;
    },
    file => {
        if (FileIsTooOld(file)) {
            return true;
        }
        return false;
    }
    );
foreach (string file in walker)
    File.Delete(file);
foreach (string dir in directoriesToDelete)
    Directory.Delete(dir);

Answer 5

我增强了John's solution，实现了缺失代码、错误处理和检查：

/* Given a directory path and a datetime,
 * recursively delete all files and directories contained in such directory
 * (given directory included) that are younger than the given date.
 */
private bool DeleteDirectoryTree(string dir, DateTime keepFilesYoungerThan)
{
    //checks
    if (String.IsNullOrEmpty(dir) || !Directory.Exists(dir))
        return false;

    //recurse on children directories
    foreach (string childDir in Directory.GetDirectories(dir))
        DeleteDirectoryTree(childDir, keepFilesYoungerThan);

    //loop on children files
    foreach (string file in Directory.GetFiles(dir))
    {
        //calculate file datetime
        DateTime fileDT = new DateTime(Math.Max(File.GetCreationTime(file).Ticks, File.GetLastWriteTime(file).Ticks));
        //if file is old, delete it
        if (fileDT <= keepFilesYoungerThan)
            try
            {
                File.Delete(file);
                Log("Deleted file " + file);
            }
            catch (Exception e)
            {
                LogError("Could not delete file " + file + ", cause: " + e.Message);
            }
    }

    //if this directory is empty, delete it
    if (!Directory.EnumerateFileSystemEntries(dir).Any())
        try
        {
            Directory.Delete(dir);
            Log("Deleted directory " + dir);
        }
        catch (Exception e)
        {
            LogError("Could not delete directory " + dir + ", cause: " + e.Message);
        }

    return true;
}