My C# app is locking a file, how I can find where it does it?

Question

I'm writing code that check files path calculate hash (SHA1) and copy them. I made sure that I do not lock them like for example using

public static string SHA1(string filePath)
    {
        var fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);
        var formatted = string.Empty;
        using (var sha1 = new SHA1Managed())
        {
            byte[] hash = sha1.ComputeHash(fs);
            foreach (byte b in hash)
            {
                formatted += b.ToString("X2");
            }
        }
        return formatted;
    }

So how I can, in Visual Studio, find where it does lock the file?

Answer 1

There is a little windows soft : process explorer and in this you can find which process has an handle on a file :

http://technet.microsoft.com/en-us/sysinternals/bb896653.aspx

Answer 2

Can you keep the above syntax as and give a try?

using(var fs = new FileStream(filePath, FileMode.Open, FileAccess.Read))
{
//Your code goes here.
} 

Answer 3

Locking usually happens whenever you create a file stream on a file without later closing that stream. Unless you call fs.Close(); in your code, your application will keep the file open (and thus locked).

You could wrap this in a try-finally block or try the code that Siva Gopal posted.

Answer 4

You assumption that opening the file stream with just FileAccess.Read will not lock the file is faulty; the file is locked while it has been opened for a file operation and has not been closed.

A FileStream does not close an opened file until the FileStream is garbage collected or you explicitly call its Close or Dispose method. Either insert such an explicit call as soon as you are done with the file you opened, Or wrap the use of the FileStream in a using statement, which implies the call to Dispose, like other answers suggest.