using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.IO;

namespace StreamTest

{

    class Program

    {

        static void Main(string[] args)

        {

            byte[] buffer = null;

            string testString = "Stream! Hello world";

            char[] readCharArray = null;

            byte[] readBuffer = null;

            string readString = string.Empty;

            //MemoryStream

            using (MemoryStream stream = new MemoryStream())

            {

                Console.WriteLine("初始化字符串为：{0}", testString);

                //如果该流可写

                if (stream.CanWrite)

                {

                    //尝试将testString写入流中

                    buffer = Encoding.Default.GetBytes(testString);

                    //我们从该数组的第一个位置开始写，长度为3，写完之后stream 中便有了数据

                    stream.Write(buffer, 0, 3);

                    Console.WriteLine("现在Stream.Positon在第{0}位置", stream.Position + 1);

                    //从刚才结束的位置往后移3位，到第7位

                    long newPositionInStream = stream.CanSeek ? stream.Seek(3, SeekOrigin.Current) : 0;

                    Console.WriteLine("重新定位后Stream.Position在第{0}位置", newPositionInStream + 1);

                    if (newPositionInStream <buffer.Length)

                    {

                        stream.Write(buffer, (int)newPositionInStream, buffer.Length - (int)newPositionInStream);

                    }

                    stream.Position = 0;

                    //设置一个空盒子来接收流中的数据，长度根据stream的长度来决定

                    readBuffer = new byte[stream.Length];

                    //设置stream 总的读取数量

                    //注意！ 这时候流已经把数据读到了readBuffer中

                    int count = stream.CanRead ? stream.Read(readBuffer, 0, readBuffer.Length) : 0;

                    int charCount = Encoding.Default.GetCharCount(readBuffer, 0, count);

                    readCharArray = new char[charCount];

                    Encoding.Default.GetDecoder().GetChars(readBuffer, 0, count, readCharArray, 0);

                    for (int i = 0; i < readCharArray.Length;i++ )

                    {

                        readString += readCharArray[i];

                    }

                    Console.WriteLine("读取的字符串为：{0}", readString);

                }

                stream.Close();

            }

            Console.ReadLine();

        }

    }

}