FileStream file = File.Open(@"F:\file.txt", FileMode.Open); //初始化文件流
byte[] array = new byte[file.Length];//初始化字节数组
file.Read(array, 0, array.Length);//读取流中数据把它写到字节数组中
file.Close();//关闭流
string str = Encoding.Default.GetString(array);//将字节数组内容转化为字符串
Console.WriteLine(str);

FileStream file = File.Open(@"F:\file.txt", FileMode.Append);//初始化文件流
byte[] array = Encoding.UTF8.GetBytes("Hello World!你好");//给字节数组赋值
file.Write(array, 0, array.Length);//将字节数组写入文件流
file.Close();//关闭流

string str = "Hi!你好！";
byte[] array = Encoding.UTF8.GetBytes(str);//将字符串转化为字节数组
MemoryStream memory = new MemoryStream(array);//初始化MemoryStream类
byte[] arrayNew = memory.ToArray();//将内存中的数据转换为字节数组
string strNew = Encoding.UTF8.GetString(arrayNew);//将字节数组转换为字符串

BufferedStream封装流
FileStream file1 = File.Open(@"F:\file1.txt", FileMode.OpenOrCreate,FileAccess.Read);//读取文件流
FileStream file 2= File.Open(@"F:\file2.txt", FileMode.OpenOrCreate,FileAccess.Write);//写入文件流

byte[] array = new byte[4096];
      
BufferedStream bufferedInput = new BufferedStream(file1);//封装文件流
BufferedStream bufferedOutput = new BufferedStream(file2);//封装文件流

bufferedInput.Read(array, 0, array.Length);
bufferedOutput.Write(array, 0, array.Length);

int bytesRead = 0;
while ((bytesRead = bufferedInput.Read(array, 0, 4096)) > 0)//读取到了数据
  {
    bufferedOutput.Write(array, 0, bytesRead);
    Console.WriteLine(bytesRead);
   }
bufferedInput.Close();//关闭各种流
bufferedOutput.Close();
file1.Close();
file2.Close();

服务器
TcpListener lis=new TcpListener(5000); //服务器监听
lis.Start();//启动
Socket sock=lis.AcceptSocket();//阻塞，直到有客户端连接

NetworkStream networkStream = new NetworkStream(sock);//得到Socket中的流
if (netStream.DataAvailable)   //如果客户端发送了消息
{
   byte[] data = new byte[1024];   //定义一个字节数组，用来存放接收的数据
   int len = netStream.Read(data, 0, data.Length);  //从位置开始，读取到字节数组末尾
   string line = Encoding.Default.GetString(data, 0, len);  //把收到的字节转换为字符串
}

客户端
TcpClient client = new TcpClient();//客户端tcp对象
client.Connect("127.0.0.1", 5000);//连接服务器
NetworkStream myStream = client.GetStream();//得到网络流
                
byte[] data = Encoding.Default.GetBytes("Hi，你好");  //首先把输入的字符串消息转换为字节
myStream .Write(data, 0, data.Length);  //向myStream 里写入数据
myStream .Flush();  //刷新流中的数据
myStream .Close();

StreamReader/Writer读写
StreamReader reader = new StreamReader("filePath");//初始化读取
StreamWriter writer = new StreamWriter("filePath");//初始化写入

string readStr=reader.ReadLine();//从流中读取一行
string readAff = reader.ReadToEnd();//从流中读取全部

writer.Write("Hi 你好");//写入内容
writer.WriteLine("Hi 你好");//写入一行

reader.Close();//关闭流
writer.Close();

TextReader/Writer读写
TextReader textReader = new StringReader("Hi 你好");//初始化读取流
TextWriter textWriter = new StringWriter();//初始化写入流

char[] c=new char[4096];
int chars = 0;
while ((chars = textReader.Read(c, 0, 4096)) > 0)//把流中数据写入到字符数组中
{
   textWriter.Write(c, 0, 4096);//从字符数组中读取流
}

string str= textWriter.ToString();//将流中数据写到字符串中
textReader.Close();//关闭流
textWriter.Close();