Reading file content changes in .NET

jameszhao00 picture jameszhao00 · Mar 3, 2010 · Viewed 10.6k times · Source

In Linux, a lot of IPC is done by appending to a file in 1 process and reading the new content from another process.

I want to do the above in Windows/.NET (Too messy to use normal IPC such as pipes). I'm appending to a file from a Python process, and I want to read the changes and ONLY the changes each time FileSystemWatcher reports an event. I do not want to read the entire file content into memory each time I'm looking for changes (the file will be huge)

Each append operation appends a row of data that starts with a unique incrementing counter (timestamp+key) and ends with a newline.

Answer

Andrey picture Andrey · Mar 3, 2010
    using (FileStream fs = new FileStream
       (fileName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
    {
        using (StreamReader sr = new StreamReader(fs))
        {
            while (someCondition)
            {
                while (!sr.EndOfStream)
                    ProcessLinr(sr.ReadLine());
                while (sr.EndOfStream)
                    Thread.Sleep(100);
                ProcessLinr(sr.ReadLine());            
            }
        }
    }

this will help you read only appended lines