Develop Reference

System.IO.File.Delete throws "The process cannot access the file because it is being used by another process"

Every time I save a file and delete it right away using the function below, I keep getting this error message: "System.IO.IOException: The process cannot access the file because it is being used by another process".
Waiting for a couple of minutes or closing visual studio seems to only unlock the files that you uploaded previously.
public static bool DeleteFiles(List<String> paths)
{ // Returns true on success
try
{
foreach (var path in paths)
{
if (File.Exists(HostingEnvironment.MapPath("~") + path))
File.Delete(HostingEnvironment.MapPath("~") + path);
}
}
catch (Exception ex)
{
return false;
}
return true;
}
I think that the way I'm saving the files may cause them to be locked. This is the code for saving the file:
if (FileUploadCtrl.HasFile)
{
filePath = Server.MapPath("~") + "/Files/" + FileUploadCtrl.FileName;
FileUploadCtrl.SaveAs(filePath)
}
When looking for an answer I've seen someone say that you need to close the streamReader but from what I understand the SaveAs method closes and disposes automatically so I really have no idea whats causing this

After some testing, I found the problem. turns out I forgot about a function I made that was called every time I saved a media file. the function returned the duration of the file and used NAudio.Wave.WaveFileReader and NAudio.Wave.Mp3FileReader methods which I forgot to close after I called them
I fixed these issues by putting those methods inside of a using statement
Here is the working function:
public static int GetMediaFileDuration(string filePath)
{
filePath = HostingEnvironment.MapPath("~") + filePath;
if (Path.GetExtension(filePath) == ".wav")
using (WaveFileReader reader = new WaveFileReader(filePath))
return Convert.ToInt32(reader.TotalTime.TotalSeconds);
else if(Path.GetExtension(filePath) == ".mp3")
using (Mp3FileReader reader = new Mp3FileReader(filePath))
return Convert.ToInt32(reader.TotalTime.TotalSeconds);
return 0;
}
The moral of the story is, to check if you are opening the file anywhere else in your project

I think that the problem is not about streamReader in here.
When you run the program, your program runs in a specific folder. Basically, That folder is locked by your program. In that case, when you close the program, it will be unlocked.
To fix the issue, I would suggest to write/delete/update to different folder.
Another solution could be to check file readOnly attribute and change this attribute which explained in here
Last solution could be using different users. What I mean is that, if you create a file with different user which not admin, you can delete with Admin user. However, I would definitely not go with this solution cuz it is too tricky to manage different users if you are not advance windows user.

File.Delete fails silently - how to debug?

The following code fails to delete the file and prints file delete: so I know the file exists. With my app open I am able to delete the file in file explorer.
How can I debug this?
1) File permissions? My app created the file so should be able to delete? Regardless it would throw an exception and hit my catch debug message.
2) The file exists! According to the docs any other failure besides non-existence should be caught in my catch...
if (File.Exists(fn))
{
Debug.WriteLine("file delete: " + fn);
try
{
File.Delete(fn);
}
catch
{
Debug.WriteLine("Could not delete: " + fn);
}
} else {
Debug.WriteLine("File doesn't exist: "+fn);
}
The file is saved from a RichTextBox using the following code if this matters.
TextRange range;
FileStream fStream;
range = new TextRange(mNotepad.Document.ContentStart, mNotepad.Document.ContentEnd);
fStream = new FileStream(fn, FileMode.Create);
range.Save(fStream, DataFormats.XamlPackage);
fStream.Close();

Deleting a file does not provide a guarantee that the file will actually be removed from the file system. The file might have been opened by another process, which explicitly specified delete sharing. Very similar to read and write sharing. Also available in .NET, you'd pass FileShare.Delete to the FileStream constructor.
But the physical file can of course not be removed until all processes close the file. So it lingers beyond the File.Delete() call, can be seen by File.Exists() as well. Opening the file can no longer work, that will be rejected with access denied. Otherwise an excellent reason to never use File.Exists(), it has many problems.
If you want to find out what other process has the file opened then you can use a utility like SysInternals' Handle or Process Explorer. Expect to find back a program like a virus scanner or search indexer, could be anything however. Like a .NET program :)

From MSDN:
If the file to be deleted does not exist, no exception is thrown.
Make sure your path exists. I know you said you did, but check again.
Make sure you reach the actual File.Delete line
Cheers

I had the same issue before, follow the steps to see if it helps you. As silly as it may sound. Make sure no processes other than yours are making use of that file you created? Is this application multi-threaded? Do you have services running that use the file?
Make sure your not in debug mode, and do a Build - Clean
Check that the file is still at the location and copy the file path.
Put a break point right before file deletion.
Rebuild your project after you put your break-point.
Press F5 to debug and step through the code.
Check that the file path matches the one that you have.

I tried to reproduce similar situation with my own code
string fn = #"C:\Users\Public\Pictures\Sample Pictures\Desert - Copy.jpg";
//The file is locked by Image.FromFile
Image img = Image.FromFile(fn);
//If img.Dispose() here, then file is unlocked and can be deleted
if (File.Exists(fn))
{
try
{
File.Delete(fn);
Debug.WriteLine("file delete: " + fn);
}
catch
{
//Caught
Debug.WriteLine("Could not delete: " + fn);
}
}
else
{
Debug.WriteLine("File doesn't exist: " + fn);
}
I found the file is locked by Image.FromFile() and therefore Could not delete.
For the same reason, I believe your file with path fn is locked by the Filestream ftream
Can you try to do
fStream.Dispose();
before your delete process and rerun the program to see if you can delete the file? thanks. You can dispose the fstream and create a new one if needed,right?

System.UnauthorizedAccessException while creating a file

I was trying to write a code so that I could log the error messages. I am trying to name the file with the date and would like to create a new log file for each day. After going through a little look around, I came with the following code...
class ErrorLog
{
public void WriteErrorToFile(string error)
{
//http://msdn.microsoft.com/en-us/library/aa326721.aspx refer for more info
string fileName = DateTime.Now.ToString("dd-MM-yy", DateTimeFormatInfo.InvariantInfo);
//# symbol helps to ignore that escape sequence thing
string filePath = #"c:\users\MyName\mydocuments\visual studio 2012\projects\training\" +
#"discussionboard\ErrorLog\" + fileName + ".txt";
if (File.Exists(filePath))
{
// File.SetAttributes(filePath, FileAttributes.Normal);
File.WriteAllText(filePath, error);
}
else
{
Directory.CreateDirectory(filePath);
// File.SetAttributes(filePath, FileAttributes.Normal)
//Throws unauthorized access exception
RemoveReadOnlyAccess(filePath);
File.WriteAllText(filePath, error);
}
}
public static void RemoveReadOnlyAccess(string pathToFile)
{
FileInfo myFileInfo = new FileInfo(pathToFile);
myFileInfo.IsReadOnly = false;
myFileInfo.Refresh();
}
/*Exception thrown:
* UnAuthorizedAccessException was unhandled.
* Access to the path 'c:\users\anish\mydocuments\visual studio 2012\
* projects\training\discussionboard\ErrorLog\04\12\2013.txt' is denied.
*/
}
I found a forum that has discussed about a similar problem but using
File.SetAttrributes(filePath, FileAttributes.Normal) did not help neither did the RemoveReadOnlyAccess (included in the code above). When I check the properties of the folder, it has read only marked but even when I tick that off it comes back again. I checked the permissions on the folder and except for the special permission, which I was not able to change, everything is allowed.
Any suggestion on how I should proceed would be appreciated.
Why is access to the path denied? the link discusses about a similar problem, but I wasn't able to get my thing working with suggestions listed there.
Thanks for taking time to look at this.

Your path is strange : "My documents" directory must be "C:\Users\MyName\Documents\"
You can use Environment in order to correct it easily :
String myDocumentPath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
Note that it will acces to "My documents" folder of the user that running your exe.
Second error, CreateDirectory must have a path in argument, not a file. using like you do will create a sub-directory with the file name. So you can't create a file with this name !
Try this :
String fileName = DateTime.Now.ToString("d", DateTimeFormatInfo.InvariantInfo);
String filePath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)
+ #"\visual studio 2012\projects\training\discussionboard\ErrorLog\";
String fileFullName = filePath + fileName + ".txt";
if (File.Exists(fileFullName ))
{
File.WriteAllText(fileFullName , error);
}
else
{
Directory.CreateDirectory(filePath);
[...]
}
}

Some possible reasons:
your app is not running under account which is allowed to access that path/file
the file is being locked for writing (or maybe reading too) by some other process
The first situation could be solved by checking under which account the process is running and verifying that the account has the appropriate rights.
The other situation can be solved by checking if any other process is locking the file (e.g. use tools like 'WhosLocking' or 'ProcessExplorer'

I had to run my app as an administrator in order to write to protected folders in c:. For example if debugging your app in visual studio make sure to right click on "C:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\IDE\devenv.exe" and choose "Run As Administrator". Then open your solution from there. My app was trying to write to the root of c:\

Check your antivirus, it might be blocking the file creation.

Randomly Thrown IO Exceptions in C#

I have been working on a program to archive old client data for the company I work for. The program copies the data from the work server to the local machine, creates a .zip file of all the data, then copies it to the archive server.
After it does all that, it deletes the original files and the local copies. Every now and then, the program errors because it can't delete the local copies off my computer. It does not error every different folder that it zips. I will error after doing 300 of them, or after 5. It throws one of the 3 following errors,"The directory is not empty", "File is being used by another process", or "Access to the file is denied". I have tried setting the file attributes to normal, using a forced garbage collection, and ending the winzip process manually.
I really do not understand why it does this only sometimes. I am the admin on my computer and it should be able to delete the files. I figured something else has to be using it, but there should be nothing else using it on my machine except the program in Visual Studio. Thanks.
Below is the cleanup method where it is not deleting the files and the method that zips the files.
[MethodImplAttribute(MethodImplOptions.NoInlining)]
static void CleanUp(SqlConnection Connection, string jNumber, DirectoryInfo dir, bool error, string prefix)
{
if (!error | (!error & emptyFolder))
{
try
{
SqlCommand updateJob = new SqlCommand(string.Format("update job set archived = 1 where job = {0}", jNumber), sdiConnection);
updateJob.ExecuteNonQuery();
}
catch
{
WriteToLog("SQL Error: " + jNumber, "There was an error changing the archive bit to 1 after the job has been archived");
}
try
{
GC.Collect();
GC.WaitForPendingFinalizers();
}
catch
{
WriteToLog("Error cleaning up after processing job", "There was an error garbage collecting.");
}
try
{
//path of the temporary folder created by the program
string tempDir = Path.Combine(Path.Combine(System.Environment.CurrentDirectory, "Temp"), jNumber);
//path of the destination folder
string destDir = Path.Combine(dir.ToString(), jNumber);
//SetFileAttributes(tempDir);
try
{
File.Delete(tempDir + ".zip");
}
catch (System.IO.IOException)
{
File.Delete(tempDir + ".zip");
}
try
{
Directory.Delete(destDir, true);
}
catch (System.IO.IOException)
{
Directory.Delete(destDir, true);
}
try
{
Directory.Delete(tempDir, true);
}
catch (System.IO.IOException)
{
Directory.Delete(tempDir, true);
}
}
catch
{
WriteToLog("File Error: " + jNumber, "There was an error removing files and/or folders after the job has been archived. Please check the source server and destination server to make sure everything copied correctly. The archive bit for this job was set.");
Directory.Delete(Path.Combine(System.Environment.CurrentDirectory, "Temp"), true);
Directory.CreateDirectory(Path.Combine(System.Environment.CurrentDirectory, "Temp"));
}
}
static bool ZipJobFolder(string jNumber, string jPath)
{
try
{
string CommandStr = #"L:\ZipFiles\winzip32.exe";
string parameters = "-min -a -r \"" + jNumber + "\" \"" + jPath + "\"";
ProcessStartInfo starter = new ProcessStartInfo(CommandStr, parameters);
starter.CreateNoWindow = true;
starter.RedirectStandardOutput = false;
starter.UseShellExecute = false;
Process process = new Process();
process.StartInfo = starter;
Console.WriteLine("Creating .zip file");
process.Start();
process.WaitForExit();
Process[] processes;
string procName = "winzip32.exe";
processes = Process.GetProcessesByName(procName);
foreach (Process proc in processes)
{
Console.WriteLine("Closing WinZip Process...");
proc.Kill();
}
}
catch
{
WriteToLog(jNumber, "There was error zipping the files of this job");
return false;
}
return true;
}

I have noticed this behavior using windows explorer, while deleting large folders with a lot of files and sub-folders. But after waiting a bit and then deleting again, it appears to work fine.
Because of that, I have always assumed it was a flaky behavior of the operating system.
Although this is not a solution, you could try it by making your application sleep for a small amount of time before attempting to delete those files, and see if the error occurs still.
If the errors go away it would appear to be related to some timing issue. I would myself want to know the source of the issue though.
Commenters are pointing to Anti Virus program. That would make sense, if that is true then you need to write some code to check if the file is locked before trying to delete. If it is locked then sleep for a bit, then check again until it is no longer locked and you can go ahead and delete it.
You just need to be careful not to get into an infinite race condition.
Edit:
There is a related question about How to best wait for a filelock to release check it out for ideas.
Edit2:
Here is another possible solution Wait until file is unlocked in .Net

Most likely you are getting a sharing violation - the delete can't get the exclusive file handle. One way this happens is the AV software gets triggered and doesn't finish scanning before the call to delete. It could also be that the WinZip process isn't fully dead yet.
Several ways to handle it:
1) On failure, sleep for a few seconds & try again.
2) I would probably not use WinZip & instead use ZipStorer (http://zipstorer.codeplex.com/). It will zip the file in the process and you won't have to do the kill step & you will have much more granular control. You could also do the zips in parallel by spinning up multiple threads.

One thing I found that helps is to not try to create temp files and directories in a single File.Move or File.Copy call. Rather, manually create the parent directories, starting at the highest level and working downwards. Finally, when all parent directories exist, Move or Copy the file.

Antivirus software could be an issue because if antivirus software is currently reading your file it will cause that, to be honest I've seen this pop up many a time when using the .NET framework and I just toss the handling in a loop and attempt to do whatever file operation is needed until it no longer throws the exception. This also happens if a file is currently being copied or is being registered in the buffer of the kernel if some kind of watcher is implemented.

UnauthorizedAccessException trying to delete a file in a folder where I can delete others files with the same code

I'm getting a Unauthorized Access Exception
in a file which I can delete manually.
in a folder where I'm able to delete by code other files
and the file isn't marked as read only
besides, I'm using Windows XP in a standalone PC and I have not assigned any permissions to the folder or the file.
no other process is using the file
If it helps, this is the code where the exception ocurrs:
protected void DeleteImage(string imageName)
{
if (imageName != null)
{
string f = String.Format("~/Images/{0}", imageName);
f = System.Web.Hosting.HostingEnvironment.MapPath(f);
if (File.Exists(f))
{
if (f != null) File.Delete(f);
}
}
}
Why could this happen?

I encountered the same problem, and found that writing my own Directory.Delete wrapper fixed it up. This is recursive by default:
using System.IO;
public void DeleteDirectory(string targetDir)
{
File.SetAttributes(targetDir, FileAttributes.Normal);
string[] files = Directory.GetFiles(targetDir);
string[] dirs = Directory.GetDirectories(targetDir);
foreach (string file in files)
{
File.SetAttributes(file, FileAttributes.Normal);
File.Delete(file);
}
foreach (string dir in dirs)
{
DeleteDirectory(dir);
}
Directory.Delete(targetDir, false);
}

If the directory contains a read only file, it won't delete that using Directory.Delete. It's a silly implementation by MS.
I am surprised no one suggested this method on the internet, which deletes the directory without recursing through it and changing every file's attributes. Here's that:
Process.Start("cmd.exe", "/c " + #"rmdir /s/q C:\Test\TestDirectoryContainingReadOnlyFiles");
(Change a bit to not to fire a cmd window momentarily, which is available all over the internet)

If it's not read-only it's possible that it is currently in use by another process.

Checking the obvious first...
When you open the file property and take a look at its security settings. Does the user running the code (i.e. if this is ASP.NET, Network Services / Domain Service Account) has access to actually delete the file?
If it is not, then change it and try again.
Are you running as administrator when trying to delete this manually?
If you are, then that's probably why you are able to delete it manually. Try deleting it as the account running your ASP.NET (I'm assuming it is ASP.NET since you are using System.Web.Hosting.HostingEnvironment.MapPath.)
If both failed, try to see if any other process is actually currently using this file. Good tool to find out is SysInternal Process Monitor. Filter it by path containing your filename and you should see if anything is using it. Terminate the process and try again.

I too faced the Same Problem but eventually came up with a Generic Approach. Below are my codes.
String pathfile = "C:\Users\Public\Documents\Filepath.txt" ;
if (!Directory.Exists(pathfile))
{
File.SetAttributes(pathfile, FileAttributes.Normal);
File.Delete(pathfile);
}
using (FileStream fs = File.Create(pathfile))
{
Byte[] info = new UTF8Encoding(true).GetBytes("What Ever Your Text is");
fs.Write(info, 0, info.Length);
File.SetAttributes(pathfile, FileAttributes.ReadOnly);
}

You, the human user, have a login with certain rights. The Web server might have a different login with different rights. A user starting with IUSR_XXXX or some such thing. Make sure that user has rights to the directory.
Without more info on the context in which you are deleting the file, I assume that the Web server user has different rights to a file than you do.