c# - C# を使用して Windows フォームでメールを読む

Question

メールを Windows フォームで読もうとしました。つまり、メールの受信トレイに最初のメッセージが表示されるはずです。まずは自分のyahooアカウントを使ってみました。コードは正常に動作しますが、メッセージが表示されません。ちょうどこの結果を得ています: " +OK hello from popgate-0.8.0.450444 pop113.plus.mail.bf1.yahoo.com ".

これが私のコードです：

using System; 
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
using System.Net.NetworkInformation;
using System.Net.Security;
using System.Net.Sockets;

namespace emailcheck
 {
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        try
        {
            // create an instance of TcpClient

            TcpClient tcpclient = new TcpClient();

            // HOST NAME POP SERVER and gmail uses port number 995 for POP

            tcpclient.Connect("pop.mail.yahoo.com", 995);

            // This is Secure Stream // opened the connection between client and POP Server

            System.Net.Security.SslStream sslstream = new SslStream(tcpclient.GetStream());

            // authenticate as client  

            sslstream.AuthenticateAsClient("pop.mail.yahoo.com");

            //bool flag = sslstream.IsAuthenticated;   // check flag

            // Asssigned the writer to stream 

            System.IO.StreamWriter sw = new StreamWriter(sslstream);

            // Assigned reader to stream

            System.IO.StreamReader reader = new StreamReader(sslstream);

            // refer POP rfc command, there very few around 6-9 command

            sw.WriteLine("user@yahoo.com");

            // sent to server
            sw.Flush(); sw.WriteLine("password");

            sw.Flush();

            // RETR 1 will retrive your first email. it will read content of your first email

            sw.WriteLine("RETR 1");

            sw.Flush();
            // close the connection
            sw.WriteLine("Quit ");
            sw.Flush(); string str = string.Empty;
            string strTemp = string.Empty;
            while ((strTemp = reader.ReadLine()) != null)
            {
                // find the . character in line
                if (strTemp == ".")
                {
                    break;
                }
                if (strTemp.IndexOf("-ERR") != -1)
                {
                    break;
                }
                str += strTemp;
            }


            richTextBox1.Text = str;
          //  textBox1.Text ="Congratulation.. ....!!! You read your first gmail email ";
        }

        catch (Exception ex)
        {
            richTextBox1.Text = ex.ToString();
        }
    }
}}

メッセージを表示する方法を誰か教えてもらえますか? また、gmail、hotmail などの他のドメインのメールを確認する方法、