C# Socket大文件上传

    public sealed class SocketData
    {
        private SocketData()
        {
        }

        public static SendFileMode SendFile(Socket socket, string fileName, int maxBufferLength)
        {
            SendFileMode flag = SendFileMode.Success;
            try
            {
                using (Stream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read))
                {
                    long fileLength = fs.Length;
                    long leftLength = fileLength;
                    int readLength = 0;
                    byte[] buffer = null;
                    var file_name = System.IO.Path.GetFileName(fileName);
                    var bytefileName = System.Text.Encoding.UTF8.GetBytes(file_name + "|" + fs.Length);
                    socket.Send(bytefileName);
                    if (fileLength <= maxBufferLength)
                    {            /* 文件可以一次读取*/
                        buffer = new byte[fileLength];
                        readLength = fs.Read(buffer, 0, (int)fileLength);
                        //开始发送
                        socket.Send(buffer, SocketFlags.None);
                    }
                    else
                    {
                        while (leftLength != 0)
                        {
                            if (leftLength < maxBufferLength)
                            {
                                buffer = new byte[leftLength];
                                readLength = fs.Read(buffer, 0, Convert.ToInt32(leftLength));
                            }
                            else
                            {
                                buffer = new byte[maxBufferLength];
                                readLength = fs.Read(buffer, 0, maxBufferLength);
                            }
                            //开始发送
                            socket.Send(buffer, SocketFlags.None);
                            leftLength -= readLength;
                        }
                    }
                }
            }
            catch (IOException)
            {

                flag = SendFileMode.IOException;
            }
            return flag;
        }
    }

    public enum SendFileMode
    {
        IOException = -4,
        TimeOut = -1,
        Success = 0,
        SendFileError = -2,
        SocketException=-3
    }