ReadLinesFromTextFile

Demo.cs

@"c:\textfile.txt".ReadLinesFromTextFile().Where(x => x.Length > 10)

StringExtensions.cs

public static IEnumerable<string> ReadLinesFromTextFile(this string filename)
{
    using (var reader = new StreamReader(filename))
    {
        string line;
        while ((line = reader.ReadLine()) != null)
        {
            yield return line;
        }
    }
}