Faulty file in use error

Question

This code is the first code in my Form_Load method:

DirectoryInfo dir =new DirectoryInfo("d:\\themes.thumb");

string[] animals = new string []
{
    "Snakes",
    "SnowyOwls",
    "Tigers",
    "TropicalFish",
    "WildBeauty",
    "Wolves"
};

foreach (FileInfo fil in dir.GetFiles())
{
    for(int ii=0;ii<animals.Length;ii++)
    {
        if (fil.Name.StartsWith(animals[ii]))
        {
        try
        {
            fil.Replace(fil.FullName,fil.FullName.Replace(fil.Name,"Animals-" + fil.Name));
        }
        catch
        {
        }
    }
}

and I'm getting the following error whenever if (fil.Name.StartsWith(animals[ii])) is true:

The process cannot access the file because it is being used by another process.

What is wrong as I have not opened any files before this code?

as an idea: maybe dir.GetFiles() creates a lock on the file? — Christian Sauer
– Christian Sauer, Commented Jun 5, 2015 at 6:40
well I first thought of that but then I thought it must be really silly if just getting the file list put lock on them as its supposed to be used like this — Ashkan Mobayen Khiabani
– Ashkan Mobayen Khiabani, Commented Jun 5, 2015 at 6:42
Does this code really compile for you? What are all those private scattered around? — sstan
– sstan, Commented Jun 5, 2015 at 6:49
What's up with all the private in the code? Does that even compile? — nvoigt
– nvoigt, Commented Jun 5, 2015 at 6:49
@nvoigt someone edited my question he must have add them there were no private in my code. I cleared them again — Ashkan Mobayen Khiabani
– Ashkan Mobayen Khiabani, Commented Jun 5, 2015 at 6:52

Ashkan Mobayen Khiabani · Accepted Answer · 2015-06-05 07:00:46Z

1

You should seperate your reading logic from your update logic.

for example:

var replacements = dir.GetFiles()
                      .Where(file => animals.Any(animal => file.Name.StartsWith(animal)))
                      .Select(file => new 
                                     {
                                       OldFullName = file.FullName, 
                                       NewFullName = file.FullName.Replace(file.Name, "Animals-" + file.Name) 
                                     })
                      .ToList();

foreach (var replacement in replacements)
{
    File.Move(replacement.OldFullName, replacement.NewFullName);
}

Your replace logic has some subtle bugs (what happens with files that are in a folder called "Wolves" for example?) you may wan to work that out.

edited Jun 5, 2015 at 7:00

Ashkan Mobayen Khiabani

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answered Jun 5, 2015 at 6:56

nvoigt

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2 Comments

Ashkan Mobayen Khiabani Over a year ago

you mean that getting files locks it?

nvoigt Over a year ago

As your renaming of files actually invalidates the information in the array you got from GetFiles, I'll take a wild guess and say yes.

sstan · Accepted Answer · 2015-06-05 07:13:52Z

1

It looks like you are misunderstanding how to use the FileInfo.Replace method.

fil.Replace(fil.FullName,fil.FullName.Replace(fil.Name,"Animals-" + fil.Name));

Here you are actually trying to overwrite fil's contents with itself. That explains the error message.

You might want to read the documentation a bit more closely.

EDIT: To be absolutely clear: FileInfo.Replace is not meant to be used to perform file renames. It's meant to replace file contents. To perform a rename, you use FileInfo.MoveTo.

edited Jun 5, 2015 at 7:13

answered Jun 5, 2015 at 7:01

sstan

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4 Comments

Ashkan Mobayen Khiabani Over a year ago

yes. the replace works as rename whenever the destination file is the file itself

sstan Over a year ago

Oh my. That's the worst way to do a rename, and causes the error message you encountered. Please don't do that.

Ashkan Mobayen Khiabani Over a year ago

well what would you offer for renaming?

sstan Over a year ago

fil.MoveTo(fil.FullName.Replace(fil.Name,"Animals-" + fil.Name);

Zoltan Rajnai · Accepted Answer · 2015-06-05 06:51:21Z

0

Get LockHunter. It's a free tool which shows you which process is holding onto a particular file or folder. I found it really useful. Microsoft Process Explorer is also free and can also find open handles (Ctrl+F) by name.

answered Jun 5, 2015 at 6:51

Zoltan Rajnai

1

1 Comment

Ashkan Mobayen Khiabani Over a year ago

the program is great but I want to know where the error is. but the programs only shows that which program is using hte file

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