尝试在没有权限的情况下添加位置的文件时，如何处理未授权的Accessexception

Question

我试图从文件夹中获取所有文件：

try
{
    string[] files = Directory.GetFiles(folderBrowserDialog1.SelectedPath, "*.*", SearchOption.AllDirectories);
}
catch (UnauthorizedAccessException)
{
    throw;
}

如果我的根文件夹包含一个文件夹，用户无权访问该文件夹，则捕获了UnauthorizedAccessException，并且我的数组为空并且所有递归失败。

我如何处理这种情况并确保未经许可我的代码忽略位置，但可以使用权限添加文件？

Answer 1

请参阅另一篇文章上的SafeFileEnumerator。过去，我成功地使用了SafefileNumerator代码。当您根本无法访问单个文件时，它可以防止丢失整个枚举，因此您仍然能够通过可以访问的文件进行迭代。

编辑：我拥有的版本与我链接到的版本略有不同，所以让我分享我拥有的版本。

public static class SafeFileEnumerator
{
    public static IEnumerable<string> EnumerateDirectories(string parentDirectory, string searchPattern, SearchOption searchOpt)
    {
        try
        {
            var directories = Enumerable.Empty<string>();
            if (searchOpt == SearchOption.AllDirectories)
            {
                directories = Directory.EnumerateDirectories(parentDirectory)
                    .SelectMany(x => EnumerateDirectories(x, searchPattern, searchOpt));
            }
            return directories.Concat(Directory.EnumerateDirectories(parentDirectory, searchPattern));
        }
        catch (UnauthorizedAccessException ex)
        {
            return Enumerable.Empty<string>();
        }
    }
    public static IEnumerable<string> EnumerateFiles(string path, string searchPattern, SearchOption searchOpt)
    {
        try
        {
            var dirFiles = Enumerable.Empty<string>();
            if (searchOpt == SearchOption.AllDirectories)
            {
                dirFiles = Directory.EnumerateDirectories(path)
                                    .SelectMany(x => EnumerateFiles(x, searchPattern, searchOpt));
            }
            return dirFiles.Concat(Directory.EnumerateFiles(path, searchPattern));
        }
        catch (UnauthorizedAccessException ex)
        {
            return Enumerable.Empty<string>();
        }
    }
}

示例用法：

foreach(string fileName in SafeFileEnumerator.EnumerateFiles(folderPath, "*" + extension, SearchOption.AllDirectories))
{
    //Do something with filename, store into an array or whatever you want to do.
}

Answer 2

您可以使用filesysteminfo对象和递归来完成此操作：

static List<string> files = new List<string>();
static void MyMethod() {
    DirectoryInfo dir = new DirectoryInfo(folderBrowserDialog1.SelectedPath);
    ProcessFolder(dir.GetFileSystemInfos());
}
static void ProcessFolder(IEnumerable<FileSystemInfo> fsi) {
    foreach (FileSystemInfo info in fsi) {
        // We skip reparse points 
        if ((info.Attributes & FileAttributes.ReparsePoint) == FileAttributes.ReparsePoint) {
            Debug.WriteLine("Skipping reparse point '{0}'", info.FullName);
            return;
        }
        if ((info.Attributes & FileAttributes.Directory) == FileAttributes.Directory) {
            // If our FileSystemInfo object is a directory, we call this method again on the
            // new directory.
            try {
                DirectoryInfo dirInfo = (DirectoryInfo)info;
                ProcessFolder(dirInfo.GetFileSystemInfos());
            }
            catch (Exception ex) {
                // Skipping any errors
                // Really, we should catch each type of Exception - 
                // this will catch -any- exception that occurs, 
                // which may not be the behavior we want.
                Debug.WriteLine("{0}", ex.Message);
                break;
            }
        } else {
            // If our FileSystemInfo object isn't a directory, we cast it as a FileInfo object, 
            // make sure it's not null, and add it to the list.
            var file = info as FileInfo;
            if (file != null) {
                files.Add(file.FullName);
            }
        }
    }
}

MyMethod采用您选择的路径并使用它创建一个DirectoryInfo对象，然后调用GetFileSystemInfos()方法并将其传递给ProcessFolder方法。

ProcessFolder方法查看每个 FileSystemInfo对象，跳过重新点点，如果FileSystemInfo对象是目录，请再次调用ProcessFolder方法 - 否则，它将FileSystemInfo对象施放为FileInfo对象，请确保其不是null，然后将文件名添加到列表中。

更多阅读：

• filesysteminfo类
• DirectoryInfo类
• FileInfo类