Check if a file/sub directory is in use and then delete if it is not

Question

I have a folder which consists of several files and sub folders. I want to empty it but some files may be in use. So I want to do a check if the file is in use and then based on that I want to delete it or skip it. Best possible way ?

Thanks.

try {delete_the_file} catch(Exception) {} ... in words: You put the call to delete in a try/catch and if you catch an exception it wasn't able to delete (for one reason or another), so you continue with the next one — devnull69, May 15 '14 at 12:08
Was trying to avoid the Catch. But it seems like the best way to solve this issue. Thanks!!! — Avenger789, May 19 '14 at 06:52

score 1 · Accepted Answer · answered May 15 '14 at 12:12

The most quick and straight forward way to "delete-or-skip" files I can think of is ... swallowing the IOException you get when something goes south while handling files.

//collectionOfFilesToDelete = string []{"path\file1.txt", "path\file2.txt", ...}
foreach(var fileName in collectionOfFilesToDelete)
    try
    {
        File.Delete(fileName);
    }
    catch(IOException ex)
    {
        // empty on purpose!
    }

I'm omitting all the accessory code (path handling etc.)

score 0 · Answer 2 · answered May 15 '14 at 12:08

You roughly need to check as:

protected virtual bool IsFileinUse(FileInfo file)
{
   FileStream stream = null;

   try
   {
     stream = file.Open(FileMode.Open, FileAccess.ReadWrite, FileShare.None);
   }
   catch (IOException)
   {
     //the file is unavailable because it is:
     //still being written to
     //or being processed by another thread
     //or does not exist (has already been processed)
     return true;
   }
   finally
   {
     if (stream != null)
     stream.Close();
   }
 return false; 
}

Seems silly to attempt to open the file just to check if it can be deleted, why not just attempt to delete it and deal with the exception then. — James, May 15 '14 at 12:17

score 0 · Answer 3 · answered May 15 '14 at 12:08

Not possible as far as I know. You will get an Exception if you delete the folder. That's all you have as far as I know.

As Zeeshan put very well you can check every file in the folder, but that does not prevent someone to have a lock on the folder.

Also, how do you know the condition hasn't changed between checking and actual deleting

score 0 · Answer 4 · answered May 15 '14 at 12:12

It's really just a case of catching the appropriate exception on File.Delete and ignoring it, according to the docs an IOException is thrown if a file is currently in use or locked

public static void ClearFolder(string targetDirectory, bool removeAfterwards)
{
    // delete files in folder
    foreach (var file in Directory.GetFiles(targetDirectory))
    {
        try
        {
            File.Delete(file);
         }
         catch (IOException) 
         {
             // file is in use, skip
         }
    }

    // process sub folders
    foreach (var dir in Directory.GetDirectories(targetDirectory))
        ClearFolder(dir, true);

    // delete folder itself
    if (removeAfterwards) {
        Directory.Delete(targetDirectory);
    }
}
...
ClearFolder(folderToClear, false);

score 0 · Answer 5 · edited May 23 '17 at 12:02

0

See the link

Here you will find lot of accepted results. Basically you need to check the file to delete and if it is failed you may sure it is in use. Otherwise you can be sure it is not in use. Simple logic.

Just use a try catch block and try to delete the file.

edited May 23 '17 at 12:02

Community

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answered May 15 '14 at 12:16

MD. Nazmul Kibria

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Check if a file/sub directory is in use and then delete if it is not

5 Answers5