System.IO.File.Create locking a file

Question

I'm using System.IO.File.Create to create a file. I'm not writing to it with a stream writer, just creating it.

I get a server error in the front end when the application tries to open the newly created file - that the file is in use. Garbage collection then seems to come along and a few minutes later all is OK.

Now I know if I was using Streamwriter I would have to close it. Does the same apply to creating?

I've read that opening a stream writer to the file then immediately closing it will fix this, but it seems messy. Is there a simpler way?

Arnhem

Answer 1

File.Create returns a FileStream. You should use it like this:

using (FileStream fs = File.Create(path))
{
    //you can use the filstream here to put stuff in the file if you want to
}

Rabid

I'd have never ever expected that. – Zolnay

Yes, we all thought so. But the using statement does not work, not even if I put in fs.Close() at the end. The file still hangs. I am using .NET 4.6.1 – Denishadenison

Answer 2

Try this:

System.IO.File.Create(FullFName).Close();

Fainthearted

This is perfect for when you just want to create a blank file. – Dalia

That is so true! "I'm not writting to it with a stream writer, just creating it". – Hammy

This was what I was looking for as well. Works a charm with a blank file. Thanks. – Nobell

Not a biggy, but this violates the disposable pattern. I would replace Close() with Dispose() (which also calls Close). – Iggy

"I would replace Close() with Dispose()" or better yet, with a using statement – Tesstessa

Answer 3

Creating the file opens a FileStream to it, hence, locking it (File.Create returns the FileStream).

You must close this stream in order to access the file. This is best done with a using statement:

using(FileStream fs = File.Create(path))
{
}

Kenji

Answer 4

When using File.Create you get a FileStream returned. Until you either close the stream or until the FileStream object is disposed (by the garbage collector's finaliser) it will remain open and locked.

FileStream implements IDisposable so you can do the following:

using(FileStream fs = File.Create(filename))
{
    // Do stuff like write to the file
}

The using statement is "syntactic sugar" and causes the compiler to generate code that is functionally equivalent to:

FileStream fs = File.Create(filename)
try
{
    // Do stuff like write to the file
}
finally
{
    fs.Dispose();
}

The Dispose method calls Close internally.

Dunkin

Answer 5

I was using: System.IO.File.Create(sFullFileName);

The above .Create method was not closing the file

I now use: System.IO.File.WriteAllText(sFullFileName, "Uploading");

This method creates and closes the file (note: I put a string "Uploading" in the file, but i'm sure string.Empty will also work.

Dusky

Answer 6

The Create method will return a file handle. The file handle should be closed before re-using the file. Please see details in the MSDN article File.Create Method (String).

Summary:

The FileStream object created by this method has a default FileShare value of None; no other process or code can access the created file until the original file handle is closed.

Rejuvenate