C#：一个增强的NetworkStream（二）写入

using System;using System.Net.Sockets;using System.Text;using System.Threading;namespace Splash.Net.Sockets{    /// <summary>    /// 异步写状态对象    /// </summary>    internal class AsyncWriteStateObject    {        public ManualResetEvent eventDone;        public NetworkStream stream;        public Exception exception;    }    /// <summary>    /// 实现TcpClient的异步发送    /// </summary>    public partial class NetworkStreamPlus    {        /// <summary>        /// 异步发送        /// </summary>        /// <param name="buffer">字节数组</param>        /// <param name="offset">起始偏移量</param>        /// <param name="size">字节数</param>        public void Write(Byte[] buffer, Int32 offset, Int32 size)        {            // 用户定义对象            AsyncWriteStateObject State = new AsyncWriteStateObject            {   // 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,            };                        Byte[] BytesArray;            if (String.IsNullOrEmpty(_secretKey))            {   // 在数据前插入长度信息                Int32 Length = size + 4;    // 加入4字节长度信息后的总长度                BytesArray = new Byte[Length];                Array.Copy(BitConverter.GetBytes(Length), BytesArray, 4);                Array.Copy(buffer, offset, BytesArray, 4, size);            }            else            {   // 数据加密                Byte[] Cipher = Encrypt(buffer, offset, size);                                 // 在数据前插入长度信息                Int32 Length = Cipher.Length + 4;                BytesArray = new Byte[Length];                Array.Copy(BitConverter.GetBytes(Length), BytesArray, 4);                Array.Copy(Cipher, 0, BytesArray, 4, Cipher.Length);            }                    // 写入加长度信息头的数据            Stream.BeginWrite(BytesArray, 0, BytesArray.Length, new AsyncCallback(AsyncWriteCallback), State);            // 等待操作完成信号            if (State.eventDone.WaitOne(Stream.WriteTimeout, false))            {   // 接收到信号                if (State.exception != null) throw State.exception;            }            else            {   // 超时异常                throw new TimeoutException();            }        }        /// <summary>        /// 异步发送        /// </summary>        /// <param name="data">字节数组</param>        public void Write(Byte[] data)        {            Write(data, 0, data.Length);        }        /// <summary>        /// 异步发送        /// </summary>        /// <param name="command">字符串</param>        /// <param name="codePage">代码页</param>        /// <remarks>        /// 代码页：        ///     936：简体中文GB2312        ///     54936：简体中文GB18030        ///     950：繁体中文BIG5        ///     1252：西欧字符CP1252        ///     65001：UTF-8编码        /// </remarks>        public void Write(String command, Int32 codePage = 65001)        {            Write(Encoding.GetEncoding(codePage).GetBytes(command));        }        /// <summary>        /// 异步写入回调函数        /// </summary>        /// <param name="ar">异步操作结果</param>        private static void AsyncWriteCallback(IAsyncResult ar)        {            AsyncWriteStateObject State = ar.AsyncState as AsyncWriteStateObject;            try            {   // 异步写入结束                State.stream.EndWrite(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();            }        }    }}