/// <summary>
/// 异步接收
/// </summary>
/// <param name="data">接收到的字节数组</param>
public void Read(out Byte[] data)
{
// 用户定义对象
AsyncReadStateObject State = new AsyncReadStateObject
{ // 将事件状态设置为非终止状态，导致线程阻止
eventDone = new ManualResetEvent(false),
stream = Stream,
exception = null,
numberOfBytesRead = -1
};
Byte[] Buffer = new Byte[ReceiveBufferSize];
using (MemoryStream memStream = new MemoryStream(ReceiveBufferSize))
{
Int32 TotalBytes = 0; // 总共需要接收的字节数
Int32 ReceivedBytes = 0; // 当前已接收的字节数
while (true)
{
// 将事件状态设置为非终止状态，导致线程阻止
State.eventDone.Reset();
// 异步读取网络数据流
Stream.BeginRead(Buffer, 0, Buffer.Length, new AsyncCallback(AsyncReadCallback), State);
// 等待操作完成信号
if (State.eventDone.WaitOne(Stream.ReadTimeout, false))
{ // 接收到信号
if (State.exception != null)
{
throw State.exception;
}
if (State.numberOfBytesRead == 0)
{ // 连接已经断开
throw new SocketException();
}
else if (State.numberOfBytesRead > 0)
{
memStream.Write(Buffer, 0, State.numberOfBytesRead); break;
}
}
else
{ // 超时异常
throw new TimeoutException();
}
}
// 将流内容写入字节数组
data = (memStream.Length > 0) ? memStream.ToArray() : null;
}
}
/// <summary>
/// 异步读取回调函数
/// </summary>
/// <param name="ar">异步操作结果</param>
private static void AsyncReadCallback(IAsyncResult ar)
{
AsyncReadStateObject State = ar.AsyncState as AsyncReadStateObject;
try
{ // 异步写入结束
State.numberOfBytesRead = State.stream.EndRead(ar);
}
catch (Exception e)
{ // 异步连接异常
State.exception = e;
}
finally
{ // 将事件状态设置为终止状态，线程继续
State.eventDone.Set();
}
}
