Question

I need to know when a text file that’s opened by C# is not in use anymore – My app writes text to a txt file and sometimes it will still have a lock on it when trying to write to it again.
There is no concern that another process or word may grab the lock back after it is released.
Is there a way to determine if the file is still locked and to reattempt the write if its not locked?

Answer 1

Below is an example of reading a file using a using block, which will close the file for you:

using (FileStream fs = File.OpenRead(@"c:\path\filename.txt")) //Open the file here
{
    using (StreamReader sr = new StreamReader(fs))
    {
        while (!sr.EndOfStream)
        {
            Console.WriteLine(sr.ReadLine());
        }
    }
} //File will close when scope of this brace ends.

Some people prefer to omit the outer level of the braces when there are consecutive using blocks. I have included them for clarity. Note that a using block uses a try-finally block under the covers to ensure that your file will close even if there is an uncaught exception. This is a good thing.

See also RAII.