异步套接字缓冲数组的问题
同步套接字接受数据的时候常常是:
byte[] buffer = new byte[64];
string dataReceived = "";
try
{
  while (true)
  {
  int bytesRead = sender.Receive(buffer);
  dataReceived += Encoding.UTF8.GetString(buffer, 0, bytesRead);
  if (dataReceived.IndexOf("\r\n") > -1)
  break;
  }
}
而如果异步套接字这样写,则会报错:
public void ReceiveMsg()
{
  byte[] buffer = new byte[64]; //缓冲字节数组
  serverSocket.BeginReceive(buffer,0,buffer.Length,SocketFlags.None,new AsyncCallback(receiveCallback),buffer);
}
private void receiveCallback(IAsyncResult ar)
{
  try
  {
  byte[] buffer = (byte[])ar.AsyncState; //缓冲字节数组
  StringBuilder sb = new StringBuilder();

  while (true)
  {
  int receivedLength = serverSocket.EndReceive(ar);
  sb.Append(Encoding.UTF8.GetString(buffer, 0, receivedLength));
  if (sb.ToString().IndexOf("\r\n") > -1)
  break;
  }
  string msgString = sb.ToString();
  msgString = msgString.Substring(0,msgString.IndexOf("\r\n"));
  Console.WriteLine("收到新消息：{0}",msgString);
  }
  catch (Exception e)
  {
  Console.WriteLine(" 接收数据失败:{0}", e.Message);
  }
  finally
  {
  ReceiveMsg(); //继续监听消息
  }
}

报错:只能为每个异步操作调用一次EndReceive。这样的话要接受的信息如果大于64字节就收不了。

------解决方案--------------------

C# code

public void ReceiveMsg()
        {
            Thread t = new Thread(new ThreadStart(receiveCallback));
            t.Start();
        }
        private void receiveCallback()
        {
byte[] buffer = new byte[64]; 
string dataReceived = ""; 
try 
{ 
    while (true) 
    { 
        int bytesRead = sender.Receive(buffer); 
        dataReceived += Encoding.UTF8.GetString(buffer, 0, bytesRead); 
        if (dataReceived.IndexOf("\r\n")  > -1) 
            break; 
    } 
} 
     }

------解决方案--------------------
C# code

StringBuilder sb = new StringBuilder(); 
byte[] buffer = new byte[64]; //缓冲字节数组 
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