电子邮件的发送与接收实例

阳光穿透心脏的1/2处 2022-08-27 12:58 175阅读 0赞

这个就不写很多不同类的属性和方法了。其中涉及的类有MailMessage类，SmtpClient类

其实可有还有相关的Attachment类：表示电子邮件的附件

以下是我看的一本书中的实例，我也就直接贴实例代码了：

一共三个窗体：Form1,frmSend,frmReceive

首先是Form1窗体：

![20140607152002609][]

后台代码：

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;
    
    namespace EmailSendAndReceive
    {
        public partial class Form1 : Form
        {
            public Form1()
            {
                InitializeComponent();
            }
    
            private void 邮件发送ToolStripMenuItem_Click(object sender, EventArgs e)
            {
                frmSend frmsend = new frmSend();
                frmsend.MdiParent = this;
                frmsend.Show();
            }
    
            private void 邮件接收ToolStripMenuItem_Click(object sender, EventArgs e)
            {
                frmReceive frmreceive = new frmReceive();
                frmreceive.MdiParent = this;
                frmreceive.Show();
            }
        }
    }

其次是邮件发送窗体：

![20140607152136406][]

后台代码：

最后是邮件接收窗体：

![20140607152258078][]

后台代码：

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 EmailSendAndReceive
    {
        public partial class frmReceive : Form
        {
            public frmReceive()
            {
                InitializeComponent();
            }
            public static string strserver;     //存储邮件服务器
            public static string pwd;           //存储用户登录邮箱的密码
            public static int k;                //存储邮件数目
            public static TcpClient tcpclient;  //实例化TcpClient对象，用来建立客户端连接
            public static StreamReader sreader; //通过流读取邮件内容
            public static string strRet;        //存储邮件内容
            //向服务器发送命令
            private string SendPopCmd(TcpClient tcpclient, string strCmd)
            {
                Byte[] arrCmd;
                string strRet;
                Stream stream;
                stream = tcpclient.GetStream();
                strCmd = strCmd + "\r\n";
                arrCmd = Encoding.Default.GetBytes(strCmd.ToCharArray());
                stream.Write(arrCmd, 0, strCmd.Length);
                strRet = sreader.ReadLine();
                return strRet;
            }
            //该方法用来对获得连接的用户身份进行验证
            private string Logon(TcpClient tcpclient, string user, string pass)
            {
                string strRet;                                   //存储用户登录信息
                strRet = SendPopCmd(tcpclient, "user " + user);　//向登录服务器发送用户名
                strRet = SendPopCmd(tcpclient, "pass " + pass);  //想登录服务器发送密码
                return strRet;
            }
            //获取登录邮箱的各种信息
            private string[] StaticMailBox(TcpClient tcpclient)
            {
                string strRet;
                strRet = SendPopCmd(tcpclient, "stat");          //向服务器发送信息返回邮箱的统计资料
                if (JudgeString(strRet) != "+OK")
                {
                    return "-ERR -ERR".Split(" ".ToCharArray());
                }
                else
                {
                    string[] arrRet = strRet.Split(" ".ToCharArray());
                    return arrRet;
                }
            }
            //判断返回的字符串信息，如果是“+OK”，证明登录成功，否则登录失败
            private string JudgeString(string strCheck)
            {
                if (strCheck.Substring(0, 3) != "+OK")
                {
                    return "-ERR";
                }
                else
                    return "+OK";
            }
            //根据输入的邮件编号读取邮件信息
            private string[] PopMail(TcpClient tcpclient, int i)
            {
                string strRet;
                string[] arrRet = new string[20];
                bool strBody = false;
                string[] arrTemp;
                //获取由参数标识的邮件的全部文本
                strRet = SendPopCmd(tcpclient, "retr " + i.ToString());
                if (JudgeString(strRet) != "+OK")
                {
                    return "-ERR -ERR".Split(" ".ToCharArray());
                }
                arrRet[0] = "+OK";
                while (sreader.Peek() != 46)
                {
                    strRet = sreader.ReadLine();
                    arrTemp = strRet.Split(":".ToCharArray());
                    if (strRet == "")
                        strBody = true;                     //现在开始接收 Body 的信息
                    if (arrTemp[0].ToLower() == "date")
                        arrRet[1] = arrTemp[1];             //信件的发送日期
                    if (arrTemp[0].ToLower() == "from")
                        arrRet[2] = (arrTemp[1].Substring(arrTemp[1].LastIndexOf("<") + 1)).Replace(">", " ");  //发信人
                    if (arrTemp[0].ToLower() == "to")
                        arrRet[3] = (arrTemp[1].Substring(arrTemp[1].LastIndexOf("<") + 1)).Replace(">", " ");  //收信人
                    if (arrTemp[0].ToLower() == "subject")
                        arrRet[4] = arrTemp[1].ToString();  //主题
                    if (strBody)
                        arrRet[5] = arrRet[5] + strRet + "\n";
                }
                return arrRet;
            }
            //对读取的邮件内容进行Base64编码
            public static string Base64Decode(string str)
            {
                return Encoding.UTF8.GetString(Convert.FromBase64String(str));
            }
            //“登录”按钮事件
            private void btnLogin_Click(object sender, EventArgs e)
            {
                string user = txtMail.Text;
                string pass = txtPwd.Text;
                string[] arrRet;
                pwd = pass;
                strserver = txtPOP.Text;
                tcpclient = new TcpClient();
                try
                {
                    tcpclient.Connect(strserver, 110);       //连接远程主机
                    //初始化StreamReader对象，以便以流的形式读取远程主机中的内容
                    sreader = new StreamReader(tcpclient.GetStream(), Encoding.Default);
                    sreader.ReadLine();
                    strRet = Logon(tcpclient, user, pass);   //登录远程主机
                    if (JudgeString(strRet) != "+OK")
                    {
                        MessageBox.Show("用户名或密码不匹配");
                        return;
                    }
                    arrRet = StaticMailBox(tcpclient);       //获取远程主机中指定用户的邮件信息
                    if (arrRet[0] != "+OK")
                    {
                        MessageBox.Show("出错了！");
                        return;
                    }
                    richTextBox1.AppendText("当前用户：" + user + "\n");
                    richTextBox1.AppendText("邮箱中共有：" + arrRet[1] + "封邮件" + "\n");
                    richTextBox1.AppendText("共占：" + arrRet[2] + "Byte");
                    k = Convert.ToInt32(arrRet[1]);
                    txtPOP.ReadOnly = txtMail.ReadOnly = txtPwd.ReadOnly = true;
                    btnLogin.Enabled = false;
                    btnReceive.Enabled = true;
                    MessageBox.Show("登录成功！");
                }
                catch
                {
                    MessageBox.Show("连接服务器失败！");
                }
            }
            //“退出”按钮事件
            private void btnExit_Click(object sender, EventArgs e)
            {
                tcpclient.Close();                          //关闭远程主机连接
            }
            //“接收”邮件按钮事件
            private void btnReceive_Click(object sender, EventArgs e)
            {
                try
                {
                    if (txtNum.Text != "")
                    {
                        if (Convert.ToInt32(txtNum.Text) > k || Convert.ToInt32(txtNum.Text) <= 0)
                        {
                            MessageBox.Show("输入的索引错误");
                        }
                        else
                        {
                            richTextBox1.Clear();
                            string[] arrRets;
                            //获得远程主机上指定邮件的相关信息，存储到一个string类型的数组中
                            arrRets = PopMail(tcpclient, Convert.ToInt32(txtNum.Text));
                            richTextBox1.AppendText("当前是第" + txtNum.Text + "封信" + "\n");
                            richTextBox1.AppendText("邮件日期：" + arrRets[1] + "\n");
                            richTextBox1.AppendText("发信人：" + arrRets[2] + "\n");
                            richTextBox1.AppendText("收信人：" + arrRets[3] + "\n");
                            richTextBox1.AppendText("邮件主题：" + Base64Decode(arrRets[4]) + "\n");
                            richTextBox1.AppendText("邮件内容：" + Base64Decode(arrRets[5]));
                        }
                    }
                    else
                    {
                        MessageBox.Show("邮件索引错误");
                    }
                }
                catch
                {
                }
            }
    
            private void txtPwd_KeyPress(object sender, KeyPressEventArgs e)
            {
                if (e.KeyChar == 13)
                    btnLogin.Focus();
            }
    
            private void txtPOP_KeyPress(object sender, KeyPressEventArgs e)
            {
                if (e.KeyChar == 13)
                    txtMail.Focus();
            }
    
            private void txtMail_KeyPress(object sender, KeyPressEventArgs e)
            {
                if (e.KeyChar == 13)
                    txtPwd.Focus();
            }
    
            private void txtNum_KeyPress(object sender, KeyPressEventArgs e)
            {
                if (e.KeyChar == 13)
                    btnReceive.Focus();
            }
    
            private void frmReceive_FormClosed(object sender, FormClosedEventArgs e)
            {
                try
                {
                    tcpclient.Close();
                }
                catch { }
            }
        }
    }

[20140607152002609]: /images/20220824/244361b9d2f741018b2ca11093c397b4.png
[20140607152136406]: /images/20220824/190cc980d8404fc48dd49aa7a38d11b4.png
[20140607152258078]: /images/20220824/65b04102ad634a9eadce1e6875f39def.png