FileStream locking a file for reading and writing

Question

I have the following code block which is giving me a headache.

Logically it should work as I am using the filestream providing the lock within the using statement.

Answer 1

As in the MSDN reference the Close method

Closes the StreamReader object and the underlying stream, and releases any system resources associated with the reader.

Thus it seems that the subsequent call to StreamWriter fails to use a closed resource, giving you the message "the file is not writable".

Try this

            using (var fs = File.Open(path, FileMode.Open, FileAccess.ReadWrite, FileShare.None))
        {
            using (var sr = new StreamReader(fs))
            {
                var str = sr.ReadToEnd();
                // ...

                using (var sw = new StreamWriter(fs))
                {
                    // ...
                }
            }
        }