Socket.EndReceive工作流

在…上 microsoft site 您可以找到以下代码: ReadCallback(IAsyncResult)

static void ReadCallback(IAsyncResult ar)
{
    StateObject state = (StateObject)ar.AsyncState;
    Socket handler = state.workSocket;

    int read = handler.EndReceive(ar);

    if(read > 0)
    {
        state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, read));
        handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReadCallback), state);
    }
    else
    {
        if(state.sb.Length > 1)
        {
            string content = state.sb.ToString();

            Console.WriteLine($"Read {content.Length} bytes from socket. \nData: {content}");
        }
        handler.Close();
    }
}

我不清楚的是这一点 if/else 陈述我们为什么要这样做 BeginReceive 再说一遍,如果我们已经读了什么?

我们为什么不这样做呢

static void ReadCallback(IAsyncResult ar)
{
    StateObject state = (StateObject)ar.AsyncState;
    Socket handler = state.workSocket;

    int read = handler.EndReceive(ar);

    state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, read));

    if(state.sb.Length > 1)
    {
        string content = state.sb.ToString();

        Console.WriteLine($"Read {content.Length} bytes from socket. \nData: {content}");
    }
    handler.Close();
}