基于C#邮件客户端

利用smptClient类和POP3协议实现一个邮件客户端，能够收发邮件，在发送邮件时能添加附件

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.Net.Sockets;
using System.IO;

namespace Email
{
    public partial class Form1 : Form
    {
        public Form1（）
        {
            InitializeComponent（）;
        }
        public TcpClient Server;
        public NetworkStream NetStrm;
        public string Data;
        public StreamReader RdStrm;
        public byte[] szData;
        public string CRLF = “\r\n“;

        private void label2_Click（object sender EventArgs e）
        {

        }

        private void label1_Click（object sender EventArgs e）
        {

        }

        private void button3_Click（object sender EventArgs e）
        {
            Server = new TcpClient（tBSrv.Text 110）;


            try
            {
                NetStrm = Server.GetStream（）;
                RdStrm = new StreamReader（Server.GetStream（） System.Text.Encoding.Default）;
                listBoxStatus.Items.Add（RdStrm.ReadLine（））;
                Data = “USER “ + tBUser.Text + CRLF;
                szData = System.Text.Encoding.ASCII.GetBytes（Data.ToCharArray（））;
                NetStrm.Write（szData 0 szData.Length）;
                listBoxStatus.Items.Add（RdStrm.ReadLine（））;
                Data = “PASS “ + tBPwd.Text + CRLF;
                szData = System.Text.Encoding.ASCII.GetBytes（Data.ToCharArray（））;
                NetStrm.Write（szData 0 szData.Length）;
                listBoxStatus.Items.Add（RdStrm.ReadLine（））;
                Data = “STAT“ + CRLF;
                szData = System.Text.Encoding.ASCII.GetBytes（Data.ToCharArray（））;
                NetStrm.Write（szData 0 szData.Length）;
                string st = RdStrm.ReadLine（）;
                listBoxStatus.Items.Add（st）;
                st = st.Substring（4 st.IndexOf（“ “5） - 4）;
                int count = Int32.Parse（st）;
                if （count > 0） 
                {
                    listBoxOperate.Enabled = true;
                    btnRead.Enabled = true;
                    btnDelete.Enabled = true;
                    listBoxStatus.Items.Clear（）;
                    listBoxOperate.Items.Clear（）;
                    for （int i = 0; i < count; i++）
                        listBoxOperate.Items.Add（“第“ + （i + 1） + “封邮件“）;
                    listBoxOperate.SelectedIndex = 0;
                }

                else
                {
                    groupBoxOpe.Text = “信箱中没有邮件“;
                    listBoxOperate.Enabled = false;
                    btnRead.Enabled = false;
                    btnDelete.Enabled = false;
                }
                btnConnect.Enabled = false;
                btnDisConnect.Enabled = true;


            }
            catch（InvalidOperationException err）
            {
            

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----
     目录           0  2017-11-27 23:06  Email\
     目录           0  2017-11-27 23:06  Email\.vs\
     目录           0  2018-11-20 10:09  Email\.vs\Email\
     目录           0  2017-11-27 23:06  Email\.vs\Email\v14\
     文件       48128  2017-12-19 08:17  Email\.vs\Email\v14\.suo
     目录           0  2018-11-20 10:11  Email\.vs\Email\v15\
     文件       54272  2018-11-20 10:21  Email\.vs\Email\v15\.suo
     目录           0  2018-11-20 10:11  Email\.vs\Email\v15\Server\
     目录           0  2018-11-20 10:11  Email\.vs\Email\v15\Server\sqlite3\
     文件           0  2018-11-20 10:11  Email\.vs\Email\v15\Server\sqlite3\db.lock
     文件        4096  2018-11-20 10:11  Email\.vs\Email\v15\Server\sqlite3\storage.ide
     文件       32768  2018-11-20 10:17  Email\.vs\Email\v15\Server\sqlite3\storage.ide-shm
     文件      688072  2018-11-20 10:20  Email\.vs\Email\v15\Server\sqlite3\storage.ide-wal
     文件         857  2017-11-27 15:20  Email\Email.sln
     文件       18944  2018-11-21 09:48  Email\Email.suo
     目录           0  2018-11-20 10:20  Email\Email\
     目录           0  2017-11-27 23:06  Email\Email\bin\
     目录           0  2017-11-27 23:06  Email\Email\bin\Debug\
     文件       14336  2018-11-21 09:38  Email\Email\bin\Debug\Email.exe
     文件       34304  2018-11-21 09:38  Email\Email\bin\Debug\Email.pdb
     文件       11600  2018-11-21 09:48  Email\Email\bin\Debug\Email.vshost.exe
     文件         490  2014-01-13 21:31  Email\Email\bin\Debug\Email.vshost.exe.manifest
     文件        3669  2017-11-27 17:24  Email\Email\Email.csproj
     文件        5938  2018-11-21 09:38  Email\Email\Form1.cs
     文件       11770  2018-11-21 09:38  Email\Email\Form1.Designer.cs
     文件        5817  2018-11-21 09:38  Email\Email\Form1.resx
     目录           0  2017-11-27 23:06  Email\Email\obj\
     目录           0  2017-11-27 23:06  Email\Email\obj\x86\
     目录           0  2018-11-21 09:38  Email\Email\obj\x86\Debug\
     文件        2855  2018-11-21 09:37  Email\Email\obj\x86\Debug\DesignTimeResolveAssemblyReferences.cache
     文件        6196  2018-11-21 09:38  Email\Email\obj\x86\Debug\DesignTimeResolveAssemblyReferencesInput.cache
............此处省略55个文件信息