Question

I have a small problem. I have a tool which should parse a log file daily, unfortunately this log file is in use by the process which writes to the log and I cannot stop it.

First try was to create a copy of the file, which is not working either.

Is there any way for me to read the current text of the log file, even if it is already in use?

Answer 1

using (FileStream stream = File.Open("path to file", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
{
    using (StreamReader reader = new StreamReader(stream))
    {
        while (!reader.EndOfStream)
        {

        }
    }
}

The FileAccess specifies what YOU want to do with the file.
The FileShare specifies what OTHERS can do with the file while you have it in use.

In the example above, you can open a file for reading while other processes can have the file open for read/write access. In most cases, this will work for opening logfiles that are in use.