C# 局域网聊天 发送信息

        //发送大量文本消息
        private void sendMessage()
        {
            if (richTextBox_send.Text.Trim().Length==0 && richTextBox_send.Rtf.IndexOf("pict")<0)
            {
                MessageBox.Show("发送的消息不能为空");
                return;
            }
            
            if (Encoding.Default.GetByteCount(richTextBox_send.Text) > 1024*3)
                {
                    MessageBox.Show("发送的内容过长");
                    return;
                }
            try
            {
                //初始化接受套接字：寻址方案，以字符流方式和Tcp通信
                socketSent = new Socket(AddressFamily.InterNetwork,
                               SocketType.Stream,
                               ProtocolType.Tcp);

                //设置目标服务器IP地址和端口
                ipSent = new IPEndPoint(IPAddress.Parse(ip), 8001);

                //与目标服务器进行连接
                socketSent.Connect(ipSent);
                
                //将要发送的消息转化为字节流，然后发送
                

                socketSent.Send(Encoding.Default.GetBytes("MSG"));
                Thread.Sleep(100);
                //循环发送
                //设置缓冲区为1024byte
                byte[] buff = new byte[1024];
                int len = 0;
                MemoryStream data = new MemoryStream();
                richTextBox_accept.Rtf = richTextBox_accept.Rtf.Replace(@"\f1\par", "");
                richTextBox_send.SaveFile(data, RichTextBoxStreamType.RichText);
                data.Position = 0;
                while ((len = data.Read(buff, 0, 1024)) != 0)
                {
                    //按实际的字节总量发送信息
                    socketSent.Send(buff, 0, len, SocketFlags.None);
                    //richTextBox_accept.AppendText(Encoding.Default.GetString(buff));
                }
                data.Close();
                data.Dispose();
                socketSent.Send(Encoding.Default.GetBytes("END"));
                socketSent.Close();
            }
            catch
            {
                MessageBox.Show(user + "已经下线！");
                return;
            }
            if (richTextBox_accept.Text != "")
            {
                richTextBox_accept.SelectionColor = Color.Green;
                richTextBox_accept.AppendText("\n" + currentUser + " " + DateTime.Now.ToString("yyyy-mm-dd hh:mm:ss") + "\n");
                richTextBox_accept.SelectionColor = Color.Black;

                richTextBox_accept.Select(richTextBox_accept.Text.Length, 0);
                richTextBox_accept.SelectedRtf = richTextBox_send.Rtf;
                richTextBox_accept.Update();
                richTextBox_accept.Select(richTextBox_accept.Rtf.Length, 0);
            }
            else
            {
                richTextBox_accept.SelectionColor = Color.Green;
                richTextBox_accept.AppendText(currentUser + " " + DateTime.Now.ToString("yyyy-mm-dd hh:mm:ss") + "\n");
                richTextBox_accept.SelectionColor = Color.Black;

                richTextBox_accept.Select(richTextBox_accept.Text.Length, 0);
                richTextBox_accept.SelectedRtf = richTextBox_send.Rtf;
                richTextBox_accept.Update();
                richTextBox_accept.Select(richTextBox_accept.Rtf.Length, 0);

            }
            this.richTextBox_send.Clear();
            richTextBox_accept.ScrollToCaret();
        }

        private void btn_close_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        //组合键发送消息
        private void richTextBox_send_KeyUp(object sender, KeyEventArgs e)
        {
            if ((Control.ModifierKeys & Keys.Control) != 0 && e.KeyCode == Keys.Enter)
            {
                if (radioBtn_sendStyle2.Checked)//发送模式选择为Enter+Ctrl
                { sendMessage(); }
            }
            else if (e.KeyCode == Keys.Enter)
            {
                if (radioBtn_sendStyle1.Checked)//发送模式选择为Enter
                {
                    sendMessage();
                }
            }
        }