How to read text file by particular line separator character?

I would implement something like George’s answer, but as an extension method that avoids loading the whole file at once (not tested, but something like this):

static class ExtensionsForTextReader
{
     public static IEnumerable<string> ReadLines (this TextReader reader, char delimiter)
     {
            List<char> chars = new List<char> ();
            while (reader.Peek() >= 0)
            {
                char c = (char)reader.Read ();

                if (c == delimiter) {
                    yield return new String(chars.ToArray());
                    chars.Clear ();
                    continue;
                }

                chars.Add(c);
            }
     }
}

Which could then be used like:

using (StreamReader sr = new StreamReader(FileName, Encoding.Default))
{
     foreach (var line in sr.ReadLines ('\n'))
           Console.WriteLine (line);
}