byte[], string, Stream の相互変換

gistfile1.cs

using System;
using System.IO;
using System.Text;

namespace Sample
{
    public static class ByteArrayExtension
    {
        public static string ConvertToString(this byte[] bytes)
        {
            return Encoding.UTF8.GetString(bytes);
        }
        public static Stream ToStream(this byte[] bytes)
        {
            return new MemoryStream(bytes);
        }
    }

    public static class StringExtension
    {
        public static byte[] ToByteArray(this string str)
        {
            return Encoding.UTF8.GetBytes(str);
        }
        public static Stream ToStream(this string str)
        {
            return str.ToByteArray().ToStream();
        }
    }

    public static class StreamExtension
    {
        public static byte[] ReadAsByteArray(this Stream stream)
        {
            using (var ms = new MemoryStream())
            {
                stream.CopyTo(ms);
                return ms.ToArray();
            }
        }
        public static string ReadAsString(this Stream stream)
        {
            using (var reader = new StreamReader(stream, Encoding.UTF8))
            {
                return reader.ReadToEnd();
            }
        }
    }
}