Continue Foreach Loop On Error - c#

I want to continue my code when error comes up , but i dont know how ...
here's my code :
foreach(string path in Directory.GetDirectories(#"C:\", "*.*", SearchOption.AllDirectories)
{
Console.WriteLine(path);
}
And the error comes on foreach(string path in Directory.GetDirectories(#"C:\", "*.*", SearchOption.AllDirectories) and i don't know how to continue this loop
and the error :
Unauthorized access
And even i run my code as Administrator this error comes up again
Thanks,

The best is to use recursive search and not using SearchOption.AllDirectories, but rather SearchOption.TopDirectoryOnly
If you use SearchOption.AllDirectories, one access violation will break your entire loop even before any file/directory is processed. But if you use SearchOption.TopDirectoryOnly, you only skip what is inaccessible.
Thus, to do it, you can create a method which receives a directory path as input. And in that method, if the input directory have child directory(ies) (see Directory.GetDirectories(string path) method, you call the method again for each child directory (recursive call) before you process all the files in the directory. Else, get the files (see Directory.GetFiles) in the directory and process them immediately.
Then for the method above, one way is to prevent the code crash when you cannot access certain file/directory is by using try-catch block for each child directory reading and file reading. This way, if one file/folder cannot be accessed, your code will still be running, finding the processing the next file/directory.
Alternatively, you can use Directory.GetAccessControl() per child directory check to see if you have an access to a Directory before hand (this option is rather hard though).
Edit (code added):
Something like this will do:
public static List<string> GetAllAccessibleDirectories(string path, string searchPattern) {
List<string> dirPathList = new List<string>();
try {
List<string> childDirPathList = Directory.GetDirectories(path, searchPattern, SearchOption.TopDirectoryOnly).ToList(); //use TopDirectoryOnly
if (childDirPathList == null || childDirPathList.Count <= 0) //this directory has no child
return null;
foreach (string childDirPath in childDirPathList) { //foreach child directory, do recursive search
dirPathList.Add(childDirPath); //add the path
List<string> grandChildDirPath = GetAllAccessibleDirectories(childDirPath, searchPattern);
if (grandChildDirPath != null && grandChildDirPath.Count > 0) //this child directory has children and nothing has gone wrong
dirPathList.AddRange(grandChildDirPath.ToArray()); //add the grandchildren to the list
}
return dirPathList; //return the whole list found at this level
} catch {
return null; //something has gone wrong, return null
}
}
And to call it, you can do something like this
string rootpath = #"C:\DummyRootFolder";
List<string> dirList = GetAllAccessibleDirectories(rootpath, "*.*"); //you get all accessible directories here
In the dirList you will get all the directories that you search for, and if there is access violation along the way, it will only affects sub-directories search due to the try-catch block.
Note that the rootpath is excluded in the method. But if you want to add it to the list too, you could simply do
dirList.Insert(0, path); //do this after you get dirList
There are also more complicated ways of doing this by using Directory.GetAccessControl and PermissionSet
Hope it may clarify.

According to the documentation, you should look at EnumerateDirectories for performance reasons:
https://msdn.microsoft.com/en-us/library/c1sez4sc(v=vs.110).aspx
Also, it appears that this question has already been answered before:
Directory.EnumerateFiles => UnauthorizedAccessException
Hope this helps!

How about this:
foreach (string path in Directory.GetDirectories(#"C:\", "*.*", SearchOption.AllDirectories)) {
try {
Console.WriteLine(path);
} catch (Exception ex) {
Console.WriteLine("Unable to access directories in path: " + path);
}
}

Related

UnauthorizedAccessException with getDirectories

Hello everyone I currently got subdirectories I wanted through this call:
foreach (DirectoryInfo dir in parent)
{
try
{
subDirectories = dir.GetDirectories().Where(d => d.Exists == true).ToArray();
}
catch(UnauthorizedAccessException e)
{
Console.WriteLine(e.Message);
}
foreach (DirectoryInfo subdir in subDirectories)
{
Console.WriteLine(subdir);
var temp = new List<DirectoryInfo>();
temp = subdir.GetDirectories("*", SearchOption.AllDirectories).Where(d => reg.IsMatch(d.Name)).Where((d => !d.FullName.EndsWith("TESTS"))).Where(d => !(d.GetDirectories().Length == 0 && d.GetFiles().Length == 0)).Where(d => d.GetFiles().Length > 3).ToList();
candidates.AddRange(temp);
}
}
foreach(DirectoryInfo dir in candidates)
{
Console.WriteLine(dir);
}
so now my issue is that my final list called candidates I get nothing because im getting an access issue due to one of the folders called lost+found in my subdirectories folder in the try block. I tried using try and catch to handle the exception so I could keep doing my checks I actually dont care about this folder and im trying to just ignore it but I'm not sure how to go about ignoring it out of my get directories search any thoughts? I already tried doing a filter with .where to ignore any folder that contained the folder name but that didnt work either it just stopped my program at the folder name.
I have the same question (ResourceContext.GetForCurrentView call exception) about this exception (UnauthorizedAccessException), and this link gives an answer to the reason why this happens:
http://www.blackwasp.co.uk/FolderRecursion.aspx
Short quote:
... Key amongst these is that some of the folders that you attempt to
read could be configured so that the current user may not access them.
Rather than ignoring folders to which you have restricted access, the
method throws an UnauthorizedAccessException. However, we can
circumvent this problem by creating our own recursive folder search
code. ...
solution:
private static void ShowAllFoldersUnder(string path, int indent)
{
try
{
foreach (string folder in Directory.GetDirectories(path))
{
Console.WriteLine("{0}{1}", new string(' ', indent), Path.GetFileName(folder));
ShowAllFoldersUnder(folder, indent + 2);
}
}
catch (UnauthorizedAccessException) { }
}
You can use recursion like Microsoft explains: link.

How to get all the paths of exe in my computer with c#

Yes there any way by which i can get the paths of exe? I mean suppose i have 20 exes in my local disk c i want to get the paths of the exe like "C:\myexe.exe or it can be C:\dir\myexe.exe"
string getpathforexe[] = themethord;
foreach(string printvalue in getpathforexe)
{
messagebox.show(printvalue.tostring());
}
so what will be themethord?
What you essentially need is a safe, recursive, .exe search functions on a root folder, and you can apply it anywhere.
Something like this:
public static List<string> GetAllAccessibleFiles(string path, string searchPattern) {
List<string> dirPathList = new List<string>();
try {
string[] childFilePaths = Directory.GetFiles(path, searchPattern, SearchOption.TopDirectoryOnly);
dirPathList.AddRange(childFilePaths);
foreach (string childDirPath in Directory.GetDirectories(path)) { //foreach child directory, do recursive search
List<string> grandChildDirPath = GetAllAccessibleFiles(childDirPath, searchPattern);
if (grandChildDirPath != null && grandChildDirPath.Count > 0) //this child directory has children and nothing has gone wrong
dirPathList.AddRange(grandChildDirPath); //add the grandchildren to the list
}
return dirPathList; //return the whole list found at this level
} catch (UnauthorizedAccessException ex){
//Do something if necessary
return null; //something has gone wrong, return null
}
}
Be careful of a couple of things:
Not all directories are accessible. When you try to access an unaccessible directory, you would get UnauthorizedAccessException
By using recursive search, you want your search result to be failed only on the directory where you have no access right.
Nevertheless, if you apply this to all your folders, likely you will take very long time. It is best to apply it to particular folders which you want to search for .exe files.
Explanations:
In the function, given a path, if first lists the files in the directory top folder:
string[] childFilePaths = Directory.GetFiles(path, searchPattern, SearchOption.TopDirectoryOnly);
dirPathList.AddRange(childFilePaths);
If any of your files matches your search pattern, you add those files. Then next you check each folder consisted in your path directory:
foreach (string childDirPath in Directory.GetDirectories(path)) { //foreach child directory, do recursive search
List<string> grandChildDirPath = GetAllAccessibleFiles(childDirPath, searchPattern);
if (grandChildDirPath != null && grandChildDirPath.Count > 0) //this child directory has children and nothing has gone wrong
dirPathList.AddRange(grandChildDirPath); //add the grandchildren to the list
}
If any of the directory consists of any child folders, do recursive search to the children directories, and add the results together in the dirPathList and finally returns it:
return dirPathList; //return the whole list found at this level
Then you could get all the files with ".exe".
And in the catch, you probably want to check for the unauthorized access Exception:
catch (UnauthorizedAccessException ex){
//Do something
return null; //something has gone wrong, return null
}
You use it like this:
List<string> exefiles = YourClassNameWhoHasTheMethod.GetAllAccessibleFiles(testfolder, "*.exe"));
For example, you could test it with Recycle Bin like this:
string rbin = #"C:\$Recycle.Bin";
List<string> files = GetAllAccessibleFiles(rbin, "*.exe");
And these are what I get for the files:
C:\$Recycle.Bin\S-1-5-21-3161714743-1342575415-982792061-1001\$IYFMY6V.exe
C:\$Recycle.Bin\S-1-5-21-3161714743-1342575415-982792061-1001\$RYFMY6V.exe

Access to the path 'd:\$RECYCLE.BIN\S-1-5-21-494745725-312220573-749543506-41600' is denied

I am new to C# . I have a text box where i enter the file to search and a 'search' button. on clock of search i want it to populate the files in the folder but i get the above error. Below is my code:
string[] directories = Directory.GetDirectories(#"d:\",
"*",
SearchOption.AllDirectories);
string file = textBox1.Text;
DataGrid dg = new DataGrid();
{
var files = new List<string>();
foreach (DriveInfo d in DriveInfo.GetDrives().Where(x => x.IsReady))
{
try
{
files.AddRange(Directory.GetFiles(d.RootDirectory.FullName, file , SearchOption.AllDirectories));
}
catch(Exception ex)
{
MessageBox.Show("the exception is " + ex.ToString());
//Logger.Log(e.Message); // Log it and move on
}
}
Please help me resolve it . Thanks
The most important rule when searching on a folder which potentially contains inaccessible subfolder is:
Do NOT use SearchOption.AllDirectories!
Use SearchOption.TopDirectoryOnly instead, combined with recursive search for all the accessible directories.
Using SearchOption.AllDirectories, one access violation will break your entire loop even before any file/directory is processed. But if you use SearchOption.TopDirectoryOnly, you only skip what is inaccessible.
There is more difficult way to use Directory.GetAccessControl() per child directory check to see if you have an access to a Directory before hand (this option is rather hard though - I don't really recommend this unless you know exactly how the access system works).
For recursive search, I have this code implemented for my own use:
public static List<string> GetAllAccessibleDirectories(string path, string searchPattern) {
List<string> dirPathList = new List<string>();
try {
List<string> childDirPathList = Directory.GetDirectories(path, searchPattern, SearchOption.TopDirectoryOnly).ToList(); //use TopDirectoryOnly
if (childDirPathList == null || childDirPathList.Count <= 0) //this directory has no child
return null;
foreach (string childDirPath in childDirPathList) { //foreach child directory, do recursive search
dirPathList.Add(childDirPath); //add the path
List<string> grandChildDirPath = GetAllAccessibleDirectories(childDirPath, searchPattern);
if (grandChildDirPath != null && grandChildDirPath.Count > 0) //this child directory has children and nothing has gone wrong
dirPathList.AddRange(grandChildDirPath.ToArray()); //add the grandchildren to the list
}
return dirPathList; //return the whole list found at this level
} catch {
return null; //something has gone wrong, return null
}
}
This is how you call it
List<string> accessibleDirs = GetAllAccessibleDirectories(myrootpath, "*");
Then, you only need to search/add the files among all accessible directories.
Note: this question is quite classical though. I believe there are some other better solutions out there too.
And in case there are some directories which you particularly want to avoid after you get all your accessible directories, you could also filter the List result by LINQ using part of the directory's name as keyword (i.e. Recycle.Bins).
As Ian has specified in his post, do not use recursive file listing (Directory.GetFiles(path, searchPattern, SearchOption.AllDirectories)) in case like yours, since the first exception will stop further processing.
Also, to somewhat alleviate such issues and for better results in general, you should run this program as an Administrator. This can be done by right-clicking your application in windows explorer, and then checking Run this program as an administrator option on Compatibility tab.
Also, you should use code like below to do your search, so the intermediate exceptions do not stop further searching.
static void Main(string[] args) {
string fileToFind = "*.jpg";
var files = new List<string>();
foreach (DriveInfo d in DriveInfo.GetDrives().Where(x => x.IsReady))
files.AddRange(FindDirectory(fileToFind, d.RootDirectory.FullName));
}
/// <summary>
/// This function returns the full file path of the matches it finds.
/// 1. It does not do any parameter validation
/// 2. It searches recursively
/// 3. It eats up any error that occurs when requesting files and directories within the specified path
/// 4. Supports specifying wildcards in the fileToFind parameter.
/// </summary>
/// <param name="fileToFind">Name of the file to search, without the path</param>
/// <param name="path">The path under which the file needs to be searched</param>
/// <returns>Enumeration of all valid full file paths matching the file</returns>
public static IEnumerable<string> FindDirectory(string fileToFind, string path) {
// Check if "path" directly contains "fileToFind"
string[] files = null;
try {
files = Directory.GetFiles(path, fileToFind);
} catch { }
if (files != null) {
foreach (var file in files)
yield return file;
}
// Check all sub-directories of "path" to see if they contain "fileToFInd"
string[] subDirs = null;
try {
subDirs = Directory.GetDirectories(path);
} catch { }
if (subDirs == null)
yield break;
foreach (var subDir in subDirs)
foreach (var foundFile in FindDirectory(fileToFind, subDir))
yield return foundFile;
}

Access to the path 'c:\$Recycle.Bin\S-1-5-18' is denied

I have this code to copy all files from source-directory, F:\, to destination-directory.
public void Copy(string sourceDir, string targetDir)
{
//Exception occurs at this line.
string[] files = System.IO.Directory.GetFiles(sourceDir, "*.jpg",
SearchOption.AllDirectories);
foreach (string srcPath in files)
{
File.Copy(srcPath, srcPath.Replace(sourceDir, targetDir), true);
}
}
and getting an exception.
If I omit SearchOption.AllDirectories and it works but only copies files from F:\
Use following function instead of System.IO.Directory.GetFiles:
IEnumerable<String> GetAllFiles(string path, string searchPattern)
{
return System.IO.Directory.EnumerateFiles(path, searchPattern).Union(
System.IO.Directory.EnumerateDirectories(path).SelectMany(d =>
{
try
{
return GetAllFiles(d,searchPattern);
}
catch (UnauthorizedAccessException e)
{
return Enumerable.Empty<String>();
}
}));
}
File system objects are subject to security. Some file system objects are secured in such a way that they can only be accessed by certain users. You are encountering a file to which the user executing the code does not have sufficient rights to access.
The reason that you don't have access rights for this particular folder is to protect the security of the different users on the system. The folder in question is the recycle bin on that drive. And each different user has their own private recycle bin, that only they have permission to access. If anybody could access any other user's recycle bin, then users would be able to read each other's files, a clear violation of the system's security policy.
Perhaps the simplest way around this is to skip hidden folders at the root level of the drive. That simple change would be enough to solve your problem because you surely don't want to copy recycle bins.
That folder is a secure system folder (your bin, each drive has its own bin). Just place your file.copy into a try catch statement and ignore/log all the failures. That way you will only copy actual files and skip system files/folders.
If you really want to avoid the try catch statement. Use the fileinfo and directory info classes to figure out which folders/files are of the system and will throw an exception.
This should do the trick:
private IEnumerable<string> RecursiveFileSearch(string path, string pattern, ICollection<string> filePathCollector = null)
{
try
{
filePathCollector = filePathCollector ?? new LinkedList<string>();
var matchingFilePaths = Directory.GetFiles(path, pattern);
foreach(var matchingFile in matchingFilePaths)
{
filePathCollector.Add(matchingFile);
}
var subDirectories = Directory.EnumerateDirectories(path);
foreach (var subDirectory in subDirectories)
{
RecursiveFileSearch(subDirectory, pattern, filePathCollector);
}
return filePathCollector;
}
catch (Exception error)
{
bool isIgnorableError = error is PathTooLongException ||
error is UnauthorizedAccessException;
if (isIgnorableError)
{
return Enumerable.Empty<string>();
}
throw error;
}
}

C# How to loop a large set of folders and files recursively without using a huge amount of memory

I want to index all my music files and store them in a database.
I have this function that i call recusively, starting from the root of my music drive.
i.e.
start > ReadFiles(C:\music\);
ReadFiles(path){
foreach(file)
save to index;
foreach(directory)
ReadFiles(directory);
}
This works fine, but while running the program the amount of memory that is used grows and grows and.. finally my system runs out of memory.
Does anyone have a better approach that doesnt need 4GB of RAM to complete this task?
Best Regards, Tys
Alxandr's queue based solution should work fine.
If you're using .NET 4.0, you could also take advantage of the new Directory.EnumerateFiles method, which enumerates files lazily, without loading them all in memory:
void ReadFiles(string path)
{
IEnumerable<string> files =
Directory.EnumerateFiles(
path,
"*",
SearchOption.AllDirectories); // search recursively
foreach(string file in files)
SaveToIndex(file);
}
Did you check for the . and .. entries that show up in every directory except the root?
If you don't skip those, you'll have an infinite loop.
You can implement this as a queue. I think (but I'm not sure) that this will save memory. At least it will free up your stack. Whenever you find a folder you add it to the queue, and whenever you find a file you just read it. This prevents recursion.
Something like this:
Queue<string> dirs = new Queue<string>();
dirs.Enqueue("basedir");
while(dirs.Count > 0) {
foreach(directory)
dirs.Enqueue(directory);
ReadFiles();
}
Beware, though, that EnumerateFiles() will stop running if you don't have access to a file or if a path is too long or if some other exception occurs. This is what I use for the moment to solve those problems:
public static List<string> getFiles(string path, List<string> files)
{
IEnumerable<string> fileInfo = null;
IEnumerable<string> folderInfo = null;
try
{
fileInfo = Directory.EnumerateFiles(str);
}
catch
{
}
if (fileInfo != null)
{
files.AddRange(fileInfo);
//recurse through the subfolders
fileInfo = Directory.EnumerateDirectories(str);
foreach (string s in folderInfo)
{
try
{
getFiles(s, files);
}
catch
{
}
}
}
return files;
}
Example use:
List<string> files = new List<string>();
files = folder.getFiles(path, files);
My solution is based on the code at this page: http://msdn.microsoft.com/en-us/library/vstudio/bb513869.aspx.
Update: A MUCH faster method to get files recursively can be found at http://social.msdn.microsoft.com/Forums/vstudio/en-US/ae61e5a6-97f9-4eaa-9f1a-856541c6dcce/directorygetfiles-gives-me-access-denied?forum=csharpgeneral. Using Stack is new to me (I didn't even know it existed), but the method seems to work. At least it listed all files on my C and D partition with no errors.
It could be junction folders wich leads to infinite loop when doing recursion but i am not sure , check this out and see by yourself . Link: https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/mklink

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