how would I perform a SHA1 hash on a file?

Question

If I have a file that I want to monitor for any changes (other than looking at the file date stamps etc).

How could I perform a SHA1 hash on its contents?

Answer 1

using (FileStream stream = File.OpenRead(@"C:\File.ext"))
{
    using (SHA1Managed sha = new SHA1Managed())
    {
        byte[] checksum = sha.ComputeHash(stream);
        string sendCheckSum = BitConverter.ToString(checksum)
            .Replace("-", string.Empty);
    }
}

Calculate the checksum periodically.