/// <summary>
/// 开始接收
/// </summary>
/// <param name="stream">Socket网络流</param>
/// <param name="callback">回调函数</param>
/// <param name="state">自定义状态</param>
/// <returns>异步结果</returns>
public IAsyncResult BeginReceive(Stream stream, AsyncCallback callback, object state)
{
//stream不能为null
if (stream == null)
{
throw new ArgumentNullException(nameof(stream));
}
//回调函数不能为null
if (callback == null)
{
throw new ArgumentNullException(nameof(callback));
}
//stream异常
if (!stream.CanRead)
{
throw new ArgumentException("stream不支持读取。");
}
SocketAsyncResult result = new SocketAsyncResult(state);
//初始化SocketHandlerState
SocketHandlerState shs = new SocketHandlerState
{
Data = new byte[2],
AsyncResult = result,
Stream = stream,
AsyncCallBack = callback,
Completed = true
};
//开始异步接收长度为2的头信息
//该头信息包含要接收的主要数据长度
stream.BeginRead(shs.Data, 0, 2, EndRead, shs);
return(result);
}
/// <summary>
/// 开始发送
/// </summary>
/// <param name="data">要发送的数据</param>
/// <param name="offset">数据偏移</param>
/// <param name="count">发送长度</param>
/// <param name="stream">Socket网络流</param>
/// <param name="callback">回调函数</param>
/// <param name="state">自定义状态</param>
/// <returns>异步结果</returns>
public IAsyncResult BeginSend(byte[] data, int offset, int count, Stream stream, AsyncCallback callback, object state)
{
//data不能为null
if (data == null)
{
throw new ArgumentNullException(nameof(data));
}
//offset不能小于0和超过data长度
if (offset > data.Length || offset < 0)
{
throw new ArgumentOutOfRangeException(nameof(offset));
}
//count不能大于65535
if (count <= 0 || count > data.Length - offset || count > ushort.MaxValue)
{
throw new ArgumentOutOfRangeException(nameof(count));
}
//stream不能为null
if (stream == null)
{
throw new ArgumentNullException(nameof(stream));
}
//回调函数不能为null
if (callback == null)
{
throw new ArgumentNullException(nameof(callback));
}
//stream异常
if (!stream.CanWrite)
{
throw new ArgumentException("stream不支持写入。");
}
SocketAsyncResult result = new SocketAsyncResult(state);
//初始化SocketHandlerState
SocketHandlerState shs = new SocketHandlerState
{
Data = data,
AsyncResult = result,
Stream = stream,
AsyncCallBack = callback,
DataLength = 0
};
//锁定SendQueue
//避免多线程同时发送数据
lock (SendQueue)
{
//添加状态
SendQueue.Add(shs);
//如果SendQueue数量大于1，则表示有数据尚未发送完成
if (SendQueue.Count > 1)
{
return(result);
}
}
//获取数据长度
//ushort的最大值为65535
//转换为byte[]长度为2
var dataLength = BitConverter.GetBytes((ushort)data.Length);
//向对方发送长度为2的头信息，表示接下来要发送的数据长度
stream.Write(dataLength, 0, dataLength.Length);
//开始异步发送数据
stream.BeginWrite(shs.Data, 0, shs.Data.Length, EndWrite, shs).AsyncWaitHandle.WaitOne();
return(result);
}
