C# pop3 邮件接收程序

private void Connect_Click(object sender, System.EventArgs e)        {            //将光标置为等待状态            Cursor cr = Cursor.Current;            Cursor.Current = Cursors.WaitCursor;            String a ,b,c;              //用110端口新建POP3服务器连接            Server = new TcpClient(PopServer.Text, 110);            Status.Items.Clear();             try            {                //初始化                NetStrm = Server.GetStream();                RdStrm = new StreamReader(Server.GetStream());                Status.Items.Add(RdStrm.ReadLine());                 //登录服务器过程                Data = "USER " Username.Text CRLF;                szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray());                NetStrm.Write(szData, 0, szData.Length);                Status.Items.Add(RdStrm.ReadLine());                 Data = "PASS " Password.Text CRLF;                szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray());                NetStrm.Write(szData, 0, szData.Length);                Status.Items.Add(RdStrm.ReadLine());                 //向服务器发送STAT命令，从而取得邮箱的相关信息：邮件数量和大小                Data = "STAT" CRLF;                szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray());                NetStrm.Write(szData, 0, szData.Length);                //Status.Items.Add(RdStrm.ReadLine());                 //改变按钮的状态                Connect.Enabled = false;                Disconnect.Enabled = true;                Retrieve.Enabled = true;                 //将光标置回原来状态                Cursor.Current = cr;             }            catch (InvalidOperationException err)            {                Status.Items.Add("Error: " err.ToString());            }        }