using(FileStream fs = File.Create("test.txt"))
using(TextWriter writer = new StreamWriter(fs))
{
    writer.WriteLine("Line1");
    writer.WriteLine("Line2");
}

using(FileStream fs = File.OpenRead("test.txt"))
using(TextReader reader = new StreamReader(fs))
{
    Console.WriteLine(reader.ReadLine());
    Console.WriteLine(reader.ReadLine());
}