Listing all files in a drive other than my system drive throws an UnauthorizedAccessException.
How can I solve this problem?
Is there a way to grant my application the access it needs?
My code:
Directory.GetFiles("S:\\", ...)
Here's a class that will work:
public static class FileDirectorySearcher
{
public static IEnumerable<string> Search(string searchPath, string searchPattern)
{
IEnumerable<string> files = GetFileSystemEntries(searchPath, searchPattern);
foreach (string file in files)
{
yield return file;
}
IEnumerable<string> directories = GetDirectories(searchPath);
foreach (string directory in directories)
{
files = Search(directory, searchPattern);
foreach (string file in files)
{
yield return file;
}
}
}
private static IEnumerable<string> GetDirectories(string directory)
{
IEnumerable<string> subDirectories = null;
try
{
subDirectories = Directory.EnumerateDirectories(directory, "*.*", SearchOption.TopDirectoryOnly);
}
catch (UnauthorizedAccessException)
{
}
if (subDirectories != null)
{
foreach (string subDirectory in subDirectories)
{
yield return subDirectory;
}
}
}
private static IEnumerable<string> GetFileSystemEntries(string directory, string searchPattern)
{
IEnumerable<string> files = null;
try
{
files = Directory.EnumerateFileSystemEntries(directory, searchPattern, SearchOption.TopDirectoryOnly);
}
catch (UnauthorizedAccessException)
{
}
if (files != null)
{
foreach (string file in files)
{
yield return file;
}
}
}
}
You can the use it like this:
IEnumerable<string> filesOrDirectories = FileDirectorySearcher.Search(#"C:\", "*.txt");
foreach (string fileOrDirectory in filesOrDirectories)
{
// Do something here.
}
It's recursive, but the use of yield gives it a low memory footprint (under 10KB in my testing). If you want only files that match the pattern and not directories as well just replace EnumerateFileSystemEntries with EnumerateFiles.
Are you allowed to access the drive? Can the program access the drive when it's not run from Visual Studio? Are restrictive permissions defined in the project's Security page ("Security Page, Project Designer")?
In .net core you can do something like this below. It can search for all subdirectories recursively with good performance and ignoring paths without access.
I also tried other methods found in
How to quickly check if folder is empty (.NET)? and
Is there a faster way than this to find all the files in a directory and all sub directories? and
https://www.codeproject.com/Articles/1383832/System-IO-Directory-Alternative-using-WinAPI
public static IEnumerable<string> ListFiles(string baseDir)
{
EnumerationOptions opt = new EnumerationOptions();
opt.RecurseSubdirectories = true;
opt.ReturnSpecialDirectories = false;
//opt.AttributesToSkip = FileAttributes.Hidden | FileAttributes.System;
opt.AttributesToSkip = 0;
opt.IgnoreInaccessible = true;
var tmp = Directory.EnumerateFileSystemEntries(baseDir, "*", opt);
return tmp;
}
I solved the problem. Not really but at least the source.
It was the SearchOption.AllDirectories option that caused the exception.
But when I just list the immediate files using Directories.GetFiles, it works.
This is good enough for me.
Any way to solve the recursive listing problem?
Related
Using the EnumerateDirectories how do you enumerate only 2 folder structures down. Example: If I start at C:\, how do I get the folders inside of C as well as one additional level down?
The only thing that Directory.GetDirectories() offers so far is the SearchOption of
SearchOption.AllDirectories || SearchOption.TopDirectoryOnly
This is what I have so far:
private static List<string> GetDirectories(string path, string searchPattern = "*")
{
try
{
return Directory.GetDirectories(path, searchPattern, SearchOption.TopDirectoryOnly).ToList();
}
catch (UnauthorizedAccessException)
{
return new List<string>();
}
}
You use a counter for the level and call the method recursively.
Untested code:
private static List<string> GetDirectories(string path, int level, string searchPattern = "*")
{
if (level == 0)
return Directory.GetDirectories(path, searchPattern, SearchOption.TopDirectoryOnly).ToList();
else
{
List<string> l = new List<string>();
foreach (string path2 in Directory.GetDirectories(path, searchPattern, SearchOption.TopDirectoryOnly))
l.AddRange(GetDirectories(path2, level - 1, searchPattern));
return l;
}
}
and call like this:
return GetDirectories(yourPath, 1, yourSearchPattern);
or you can change this to drill down, then go back up for the next etc. but still using a counter.
If you need the files (though the body of your question didn't mention that, only the title), just iterate over the result, getting the files in each of the folders you got.
You could do something like this, you'll just need to add some code if you're not authorized to access the directory.
Directory.GetDirectories(path, searchPattern).ToList().ForEach(
d =>
{
try
{
searchItems.Add(d);
searchItems.AddRange(Directory.GetDirectories(d, searchPattern, SearchOption.TopDirectoryOnly));
}
catch (UnauthorizedAccessException)
{
//do something when you are not authorized
}
});
I have this test path:
private static string dCrawler = Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "TestLetters";
Is there a way to say:
foreach (item in dCrawler)
{
if (item.isFile)
{
// check file info date modified code
} else
{
foreach (fileinfo file in ...
}
}
so far I have only found ways to check a file in a directory. Is the only way to do it by having two separate loops one for files and one for folders?
You can use Directory.GetFiles(); that returns a string[] and use the string value to create your FileInfo. Like this
foreach (string n in Directory.GetFiles(dCrawler))
{
FileInfo b = new FileInfo(n);
}
To get directories, you can similarly use Directory.GetDirectories();
foreach (string n in Directory.GetDirectories(dCrawler))
{
DirectoryInfo b = new DirectoryInfo(n);
}
I have this line of code: (using LINQ)
//string folder <-- folder browser dialog.
listFiles = Directory.GetFiles(folder, "*.xml",
SearchOption.AllDirectories).Select(
fileName => Path.GetFullPath(fileName)).ToList();
But sometimes my program finds protected files, such as system files or even system folders that can't be opened.
How can I surpass this problem:
Only get file name of open/free files-folders.
You can't tell, you just have to catch the exception.
What if the file is free when doing the free check, but in use when processing?
That can be a problem. If it throws an exception when going through the directories, it stops.
If you want to ignore those directories and keep going, you have to write a recursive method to do it:
List<string> GetFiles(string folder, string filter)
{
List<string> files = new List<string>();
try
{
// get all of the files in this directory
files.AddRange(Directory.GetFiles(folder, filter));
// Now recursively visit the directories
foreach (var dir in Directory.GetDirectories(folder))
{
files.AddRange(GetFiles(dir, filter));
}
}
catch (UnauthorizedAccessException)
{
// problem accessing this directory.
// ignore it and move on.
}
return files;
}
A somewhat more memory efficient version would be:
private List<string> GetFiles(string folder, string filter)
{
var files = new List<string>();
// To create a recursive Action, you have to initialize it to null,
// and then reassign it. Otherwise the compiler complains that you're
// using an unassigned variable.
Action<string> getFilesInDir = null;
getFilesInDir = new Action<string>(dir =>
{
try
{
// get all the files in this directory
files.AddRange(Directory.GetFiles(dir, filter));
// and recursively visit the directories
foreach (var subdir in Directory.GetDirectories(dir))
{
getFilesInDir(subdir);
}
}
catch (UnauthorizedAccessException)
{
// ignore exception
}
});
getFilesInDir(folder);
return files;
}
you could use something like this, potentially you will have to tweak attribute check:
Directory.GetFiles(folder, "*.xml", SearchOption.AllDirectories)
.Select(fileName => new FileInfo(Path.GetFullPath(fileName)))
.Where(n => !n.Attributes.HasFlag(FileAttributes.System))
.Select(n => n.FullName)
.ToList();
I wrote a method that needed to find all files within a path, and I want to get all the files using recursion. Here's my current method:
public void doStart(DirectoryInfo dir, string filePattern)
{
try
{
foreach (FileInfo fileInfo in dir.GetFiles(filePattern))
{
if (fileFound != null)
{
fileFound(fileInfo);
}
}
}
catch (Exception)
{
}
try
{
foreach (DirectoryInfo dirInfo in dir.GetDirectories())
{
doStart(dirInfo, filePattern);
}
}
catch (Exception)
{
}
}
public void Start(string path, string filePattern)
{
doStart(new DirectoryInfo(path), filePattern);
}
Is there is better way to write this kind of recursion or is this good enough ?
Try something like this:
string[] filePaths = Directory.GetFiles(#dir, "*.filetype", SearchOption.AllDirectories);
This would recursively look through the directory, finding all files with a certain filetype ('.filetype') and returns a string array containing all found files.
Also, I'd recommend not to use empty catch blocks, as your application won't let you know if something went wrong. Either show a message box (or something similar) or log it to a database or something.
Further, what would your DoStart() method do if there is a subdirectory in a subdirectory? From what I'm seeing, I'd say it only searches on 1 sublevel.
Don't swallow all exceptions. If you need to ignore specific exceptions, catch those but let others bubble up
(style) Methods should be PascalCased (e.g. DoStart and `FileFound'
(style) Create an OnFileFound method instead of calling FileFound directly (I assume fileFound is an event handler?)
Other than that it looks fine to me.
Here is an example of true recursion. This will search until there are no more sub-directories to find, unlike Directory.GetFiles SearchOption.AllDirectories. You can modify this to add search filters as a parameter.
public IEnumerable<string> GetFilesRecursive(string ParentDirectory)
{
string[] subDirectories = Directory.GetDirectories(ParentDirectory);
foreach (string file in Directory.GetFiles(ParentDirectory))
{
yield return file;
}
foreach (string subDirectory in subDirectories)
{
foreach (string file in GetFilesRecursive(subDirectory))
{
yield return file;
}
}
}
I am creating a backup application where c# scans a directory. Before I use to have something like this in order to get all the files and subfiles in a directory:
DirectoryInfo di = new DirectoryInfo("A:\\");
var directories= di.GetFiles("*", SearchOption.AllDirectories);
foreach (FileInfo d in directories)
{
//Add files to a list so that later they can be compared to see if each file
// needs to be copid or not
}
The only problem with that is that sometimes a file could not be accessed and I get several errors. an example of an error that I get is:
As a result I created a recursive method that will scan all files in the current directory. If there where directories in that directory then the method will be called again passing that directory. The nice thing about this method is that I could place the files inside a try catch block giving me the option to add those files to a List if there where no errors and adding the directory to another list if I had errors.
try
{
files = di.GetFiles(searchPattern, SearchOption.TopDirectoryOnly);
}
catch
{
//info of this folder was not able to get
lstFilesErrors.Add(sDir(di));
return;
}
So this method works great the only problem is that when I scan a large directory it takes to much times. How could I speed up this process? My actual method is this in case you need it.
private void startScan(DirectoryInfo di)
{
//lstFilesErrors is a list of MyFile objects
// I created that class because I wanted to store more specific information
// about a file such as its comparePath name and other properties that I need
// in order to compare it with another list
// lstFiles is a list of MyFile objects that store all the files
// that are contained in path that I want to scan
FileInfo[] files = null;
DirectoryInfo[] directories = null;
string searchPattern = "*.*";
try
{
files = di.GetFiles(searchPattern, SearchOption.TopDirectoryOnly);
}
catch
{
//info of this folder was not able to get
lstFilesErrors.Add(sDir(di));
return;
}
// if there are files in the directory then add those files to the list
if (files != null)
{
foreach (FileInfo f in files)
{
lstFiles.Add(sFile(f));
}
}
try
{
directories = di.GetDirectories(searchPattern, SearchOption.TopDirectoryOnly);
}
catch
{
lstFilesErrors.Add(sDir(di));
return;
}
// if that directory has more directories then add them to the list then
// execute this function
if (directories != null)
foreach (DirectoryInfo d in directories)
{
FileInfo[] subFiles = null;
DirectoryInfo[] subDir = null;
bool isThereAnError = false;
try
{
subFiles = d.GetFiles();
subDir = d.GetDirectories();
}
catch
{
isThereAnError = true;
}
if (isThereAnError)
lstFilesErrors.Add(sDir(d));
else
{
lstFiles.Add(sDir(d));
startScan(d);
}
}
}
Ant the problem if I try to handle the exception with something like:
DirectoryInfo di = new DirectoryInfo("A:\\");
FileInfo[] directories = null;
try
{
directories = di.GetFiles("*", SearchOption.AllDirectories);
}
catch (UnauthorizedAccessException e)
{
Console.WriteLine("There was an error with UnauthorizedAccessException");
}
catch
{
Console.WriteLine("There was antother error");
}
Is that if an exception occurs then I get no files.
This method is much faster. You can only tel when placing a lot of files in a directory. My A:\ external hard drive contains almost 1 terabit so it makes a big difference when dealing with a lot of files.
static void Main(string[] args)
{
DirectoryInfo di = new DirectoryInfo("A:\\");
FullDirList(di, "*");
Console.WriteLine("Done");
Console.Read();
}
static List<FileInfo> files = new List<FileInfo>(); // List that will hold the files and subfiles in path
static List<DirectoryInfo> folders = new List<DirectoryInfo>(); // List that hold direcotries that cannot be accessed
static void FullDirList(DirectoryInfo dir, string searchPattern)
{
// Console.WriteLine("Directory {0}", dir.FullName);
// list the files
try
{
foreach (FileInfo f in dir.GetFiles(searchPattern))
{
//Console.WriteLine("File {0}", f.FullName);
files.Add(f);
}
}
catch
{
Console.WriteLine("Directory {0} \n could not be accessed!!!!", dir.FullName);
return; // We alredy got an error trying to access dir so dont try to access it again
}
// process each directory
// If I have been able to see the files in the directory I should also be able
// to look at its directories so I dont think I should place this in a try catch block
foreach (DirectoryInfo d in dir.GetDirectories())
{
folders.Add(d);
FullDirList(d, searchPattern);
}
}
By the way I got this thanks to your comment Jim Mischel
In .NET 4.0 there's the Directory.EnumerateFiles method which returns an IEnumerable<string> and is not loading all the files in memory. It's only once you start iterating over the returned collection that files will be returned and exceptions could be handled.
There is a long history of the .NET file enumeration methods being slow. The issue is there is not an instantaneous way of enumerating large directory structures. Even the accepted answer here has its issues with GC allocations.
The best I've been able to do is wrapped up in my library and exposed as the FindFile (source) class in the CSharpTest.Net.IO namespace. This class can enumerate files and folders without unneeded GC allocations and string marshalling.
The usage is simple enough, and the RaiseOnAccessDenied property will skip the directories and files the user does not have access to:
private static long SizeOf(string directory)
{
var fcounter = new CSharpTest.Net.IO.FindFile(directory, "*", true, true, true);
fcounter.RaiseOnAccessDenied = false;
long size = 0, total = 0;
fcounter.FileFound +=
(o, e) =>
{
if (!e.IsDirectory)
{
Interlocked.Increment(ref total);
size += e.Length;
}
};
Stopwatch sw = Stopwatch.StartNew();
fcounter.Find();
Console.WriteLine("Enumerated {0:n0} files totaling {1:n0} bytes in {2:n3} seconds.",
total, size, sw.Elapsed.TotalSeconds);
return size;
}
For my local C:\ drive this outputs the following:
Enumerated 810,046 files totaling 307,707,792,662 bytes in 232.876 seconds.
Your mileage may vary by drive speed, but this is the fastest method I've found of enumerating files in managed code. The event parameter is a mutating class of type FindFile.FileFoundEventArgs so be sure you do not keep a reference to it as it's values will change for each event raised.
I know this is old, but... Another option may be to use the FileSystemWatcher like so:
void SomeMethod()
{
System.IO.FileSystemWatcher m_Watcher = new System.IO.FileSystemWatcher();
m_Watcher.Path = path;
m_Watcher.Filter = "*.*";
m_Watcher.NotifyFilter = m_Watcher.NotifyFilter = NotifyFilters.LastAccess | NotifyFilters.LastWrite | NotifyFilters.FileName | NotifyFilters.DirectoryName;
m_Watcher.Created += new FileSystemEventHandler(OnChanged);
m_Watcher.EnableRaisingEvents = true;
}
private void OnChanged(object sender, FileSystemEventArgs e)
{
string path = e.FullPath;
lock (listLock)
{
pathsToUpload.Add(path);
}
}
This would allow you to watch the directories for file changes with an extremely lightweight process, that you could then use to store the names of the files that changed so that you could back them up at the appropriate time.
(copied this piece from my other answer in your other question)
Show progress when searching all files in a directory
Fast files enumeration
Of course, as you already know, there are a lot of ways of doing the enumeration itself... but none will be instantaneous. You could try using the USN Journal of the file system to do the scan. Take a look at this project in CodePlex: MFT Scanner in VB.NET... it found all the files in my IDE SATA (not SSD) drive in less than 15 seconds, and found 311000 files.
You will have to filter the files by path, so that only the files inside the path you are looking are returned. But that is the easy part of the job!
Maybe it will be helpfull for you.
You could use "DirectoryInfo.EnumerateFiles" method and handle UnauthorizedAccessException as you need.
using System;
using System.IO;
class Program
{
static void Main(string[] args)
{
DirectoryInfo diTop = new DirectoryInfo(#"d:\");
try
{
foreach (var fi in diTop.EnumerateFiles())
{
try
{
// Display each file over 10 MB;
if (fi.Length > 10000000)
{
Console.WriteLine("{0}\t\t{1}", fi.FullName, fi.Length.ToString("N0"));
}
}
catch (UnauthorizedAccessException UnAuthTop)
{
Console.WriteLine("{0}", UnAuthTop.Message);
}
}
foreach (var di in diTop.EnumerateDirectories("*"))
{
try
{
foreach (var fi in di.EnumerateFiles("*", SearchOption.AllDirectories))
{
try
{
// Display each file over 10 MB;
if (fi.Length > 10000000)
{
Console.WriteLine("{0}\t\t{1}", fi.FullName, fi.Length.ToString("N0"));
}
}
catch (UnauthorizedAccessException UnAuthFile)
{
Console.WriteLine("UnAuthFile: {0}", UnAuthFile.Message);
}
}
}
catch (UnauthorizedAccessException UnAuthSubDir)
{
Console.WriteLine("UnAuthSubDir: {0}", UnAuthSubDir.Message);
}
}
}
catch (DirectoryNotFoundException DirNotFound)
{
Console.WriteLine("{0}", DirNotFound.Message);
}
catch (UnauthorizedAccessException UnAuthDir)
{
Console.WriteLine("UnAuthDir: {0}", UnAuthDir.Message);
}
catch (PathTooLongException LongPath)
{
Console.WriteLine("{0}", LongPath.Message);
}
}
}
You can use this to get all directories and sub-directories. Then simply loop through to process the files.
string[] folders = System.IO.Directory.GetDirectories(#"C:\My Sample Path\","*", System.IO.SearchOption.AllDirectories);
foreach(string f in folders)
{
//call some function to get all files in folder
}