C#实现发送和接收邮件的winform邮箱（保存至MySQL本地数据库）Mail Client

一、C#邮箱总体介绍

初学C#，使用DevExpress做了个WInform的邮箱，邮箱的主界面如下所示：

主要完成的功能有

1. 邮箱客户端的登入功能，用户的邮箱和密码存储在MySQL的数据库之中，只有和数据库中信息匹配才允许登入。
2. 邮件的发送和接收功能。
3. 把用户接收的邮件存储在数据库之中，并使用GridControl进行展示。
4. 设置CN/EN语言

二、C#本地邮箱如何实现

1. 登入界面

主要登入界面如上图所示，点击sign in 之后可登入至主界面。

登入界面的UI实现很简单，就是直接从DevExpress里拖动控件完成。
具体的逻辑实现如下：

namespace Mailclient_demo1
{
    public partial class login : DevExpress.XtraEditors.XtraForm
    {
        // DBConnect is completed by me
        DBConnect DBConnect1 = new DBConnect();
        public static String emailaddress, password;
        public login()
        {
            InitializeComponent();
        }
        private void Btn_Register_Click(object sender, EventArgs e)
        {
            this.FormBorderStyle = FormBorderStyle.None;//无边框
        }
		//点击登入按钮
        private void button1_Click(object sender, EventArgs e)
        {
            emailaddress = textBox_email_address.Text;
            password = textBox_password.Text;
            //Test if the emailaddress and password is in the database
            if (DBConnect1.check(emailaddress, password) == true)
            {
                this.Hide();               
                //show main
                Mainform Mf = new Mainform();
                Mf.ShowDialog();

            }
            else
            {
                MessageBox.Show("sad...login unsuccessfully");
            }

        }
    }
}

首先需要在数据库中保存已有的email address 和 password的信息:

然后和数据库连接：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
//Add MySql Library
using MySql.Data.MySqlClient;
namespace Mailclient_demo1
{
    class DBConnect
{
    private MySqlConnection connection;
    private string server;
    private string database;
    private string uid;
    private string password;

    //Constructor
    public DBConnect()
    {
        Initialize();
    }

        //Initialize values
        private void Initialize()
        {
            server = "localhost";
            database = "emailclient";
            uid = "root";
            password = "Zhu19971125123!";
            string connectionString;
            connectionString = "SERVER=" + server + ";" + "DATABASE=" +
            database + ";" + "UID=" + uid + ";" + "PASSWORD=" + password + ";";

            connection = new MySqlConnection(connectionString);
        }

        //open connection to database
        private bool OpenConnection()
        {
            try
            {
                connection.Open();
                return true;
            }
            catch (MySqlException ex)
            {
                switch (ex.Number)
                {
                    case 0:
                        Console.WriteLine("Cannot connect to server.  Contact administrator");
                        break;

                    case 1045:
                        Console.WriteLine("Invalid username/password, please try again");
                        break;
                }
                return false;
            }
        }

        //Close connection
        private bool CloseConnection()
        {
            try
            {
                connection.Close();
                return true;
            }
            catch (MySqlException ex)
            {
                Console.WriteLine(ex.Message);
                return false;
            }
        }
        //Search if the emailaddress and password is in the database
        public bool check(string emailaddress, string password)
        {
            String sql = "select Email_address,Password from login_email where Email_address='" + emailaddress + "'and Password='" + password + "'";
            if (this.OpenConnection() == true)
            {
                //Create Mysql Command
                MySqlCommand cmd = new MySqlCommand(sql, connection);
                MySqlDataReader sqlDataReader = cmd.ExecuteReader();
                if (sqlDataReader.HasRows)
                {
                    connection.Close();
                    this.CloseConnection();
                    return true;
                }
                else
                {
                    connection.Close();
                    this.CloseConnection();
                    return false;
                }
            }
            return false;
        }
}
}

2. 发送邮件

发送邮件的UI也很简单，拖动控件就好。

首先得使用SMTP来发送邮件，具体见代码

using System.Net;
using System.Net.Mail;
//Test send email
namespace Mailclient_demo1
{

    class Class1
    {
        public string sendsuc = "Send successfully";
        public string smtpAddress = "smtp-mail.outlook.com";
        public int portNumber = 587;
        public bool enableSSL = true;
        public string emailFromAddress = "Sender Email Address  "; //Sender Email Address  
        public string password = "Sender Password"; //Sender Password 
        public string emailToAddress = "Receiver Email Address  "; //Receiver Email Address  
        public string subject = "Hello";
        public string body = "Hello, This is Email sending test using gmail.";
        public string attachment ="";

        //Use Smtp to send email
        public void SendEmail()
        {
            using (MailMessage mail = new MailMessage())
            {
                mail.From = new MailAddress(emailFromAddress);
                mail.To.Add(emailToAddress);
                mail.Subject = subject;
                mail.Body = body;
                mail.IsBodyHtml = true;
                //--Uncomment this to send any attachment
                if (attachment != "")
                {
                    mail.Attachments.Add(new Attachment(attachment));
                }
                using (SmtpClient smtp = new SmtpClient(smtpAddress, portNumber))
                {
                    smtp.Credentials = new NetworkCredential(emailFromAddress, password);
                    smtp.EnableSsl = enableSSL;
                    smtp.Send(mail);
                }
            }
        }
    }
}

接下来写逻辑来调用send email

namespace Mailclient_demo1
{
    public partial class SendClient : DevExpress.XtraEditors.XtraForm
    {
        //全局的 c1 means send email function c1
        Class1 c1 = new Class1();
        public SendClient()
        {
            InitializeComponent();
            //Obtain the basic inforamtion
            

        }
        private void btn_sendmail_Click(object sender, EventArgs e)
        {
            //send
            c1.emailToAddress = textBox_To.Text;
            c1.subject = textBox_Subject.Text;
            c1.body = textBox_Body.Text;
            c1.SendEmail();
            MessageBox.Show(c1.sendsuc);
        }
        //add attachments
        private void btn_attach_Click(object sender, EventArgs e)
        {
            OpenFileDialog dialog = new OpenFileDialog();
            dialog.Title = "choose the document";
            dialog.Multiselect = false;
            if (dialog.ShowDialog() == DialogResult.OK)
            {
                c1.attachment = dialog.FileName;
                label_attach.Text = dialog.FileName;
            }
        }

    }
}

3. 接收邮件

Imap接收邮件

接收邮件会比较复杂，因为C#中没有自带的Imap库，所以需要在NuGet中下载EAGetMail这个库。

然后用MailServer来接收邮件

namespace Mailclient_demo1
{
    class Reveivemailclass
    {
        public string show_receviemial_num(string emailaddress, string password)
        {
            string output = "";

            try
            {
                MailServer oServer = new MailServer("outlook.office365.com",
                                emailaddress,
                                password,
                                ServerProtocol.Imap4);

                // Enable SSL/TLS connection, most modern email server require SSL/TLS by default
                oServer.SSLConnection = true;
                oServer.Port = 993;

                MailClient oClient = new MailClient("TryIt");
                oClient.Connect(oServer);

                MailInfo[] infos = oClient.GetMailInfos();

                Console.WriteLine("Total {0} email(s)\r\n", infos.Length);
                output = infos.Length.ToString();

                for (int i = 0; i < infos.Length; i++)
                {
                    string line = "";
                    MailInfo info = infos[i];
                    Console.WriteLine("Index: {0}; Size: {1}; UIDL: {2}",
                        info.Index, info.Size, info.UIDL);
                    line = line + ("Index: {0}; Size: {1}; UIDL: {2}",
                        info.Index, info.Size, info.UIDL) + "\r\n";

                    // Receive email from IMAP4 server
                    Mail oMail = oClient.GetMail(info);
                    //form
                    Console.WriteLine("From: {0}", oMail.From.ToString());
                    line = line + ("From: ", oMail.From.ToString()) + "\r\n";
                    //to
                    Console.WriteLine("To[0]: {0}", oMail.To[0].ToString());
                    line = line + ("To", oMail.To[0].ToString()) + "\r\n";
                    Console.WriteLine("ReceivedDate: {0}", oMail.ReceivedDate.ToString());
                    line = line + ("ReceivedDate: ", oMail.ReceivedDate.ToString()) + "\r\n";
                    Console.WriteLine("Subject: {0}\r\n", oMail.Subject);
                    line = line + ("Subject: ", oMail.Subject) + "\r\n";
                    Console.WriteLine("TextBody: {0}\r\n", oMail.TextBody);
                    line = line + "TextBody: " + oMail.TextBody + "\r\n";
                    line = line + "\r\n";
                    
                }

                // Quit and expunge emails marked as deleted from IMAP4 server.
                oClient.Quit();
                Console.WriteLine("Completed!");
            }
            catch (Exception ep)
            {
                Console.WriteLine(ep.Message);
            }
            return output;
        }

接收邮件并保存到MySQL数据库之中

        public void save_receivemail(String emailaddress, string password)
        {
            string output = "";
            MailServer oServer = new MailServer("outlook.office365.com",
                                emailaddress,
                                password,
                                ServerProtocol.Imap4);
            // Enable SSL/TLS connection, most modern email server require SSL/TLS by default
            oServer.SSLConnection = true;
            oServer.Port = 993;

            MailClient oClient = new MailClient("TryIt");
            oClient.Connect(oServer);
            MailInfo[] infos = oClient.GetMailInfos();
            Console.WriteLine("Total {0} email(s)\r\n", infos.Length);
            String sender, recipient, subject, body;
            output = output + "Total " + infos.Length + "email(s)\r\n";

            //Open database
            MySqlConnection connectionre;
            string connectionString;
            connectionString = "SERVER=" + "localhost" + ";" + "DATABASE=" +
            "emailclient" + ";" + "UID=" + "root" + ";" + "PASSWORD=" + "Zhu19971125123!" + ";";
            connectionre = new MySqlConnection(connectionString);
            connectionre.Open();
            //Display no more than 20
            int lengthinfo = infos.Length;
            if (lengthinfo >= 20)
            {
                lengthinfo = 20;
            }
            //save
            for (int i = 0; i < lengthinfo; i++)
            {
                MailInfo info = infos[i];
                // Receive email from IMAP4 server
                Mail oMail = oClient.GetMail(info);
                //把"fangzheng zhu" <fangzheng.zhu@tradex.com.sg> 变成 <fangzheng.zhu@tradex.com.sg>

                String sender_ori = oMail.From.ToString();
                string[] sArray = sender_ori.Split(new char[2] { '<', '>' });
                sender = "<" + sArray[1] + ">";
                String recipient_ori = oMail.To[0].ToString();
                string[] rArray = recipient_ori.Split(new char[2] { '<', '>' });
                recipient = "<" + rArray[1] + ">";
                subject = oMail.Subject.ToString();
                subject=subject.Substring(0, subject.Length - 16);
                body = oMail.TextBody.ToString();

                //check if is already in the database
                //save to database

                /*String sqlsave = "if not exists(select count(*) from receive_email " +
                    "where Sender = '"+ oMail.From.ToString() + "' and Recipient = '"+ oMail.To[0].ToString()+ "' and Subject = '"+ subject+"')" +
                    "INSERT INTO receive_email(Sender,Recipient,Subject) " +
                    "VALUES('" + oMail.From.ToString() + "','" + oMail.To[0].ToString() + "','" + subject + "')";*/

                /*String sqlsave = "if not exists(select count(*) from receive_email " +"')" +
                    "INSERT INTO receive_email(Sender,Recipient,Subject) " +
                    "VALUES('" + oMail.From.ToString() + "','" + oMail.To[0].ToString() + "','" + subject + "')";*/
                //IGNORE
                String sqlsave = "INSERT IGNORE INTO receive_email(Sender,Recipient,Subject,Body) " +
                "VALUES('" + sender + "','" + recipient + "','" + subject + "','"+ body + "')";

                MySqlCommand cmdsave = new MySqlCommand(sqlsave, connectionre);
                cmdsave.ExecuteNonQuery();
            }
            connectionre.Close();
            oClient.Quit();
            Console.WriteLine("Completed!");
        }

与前端UI组合逻辑

用到了GridControl这个控件

namespace Mailclient_demo1.UI
{
    public partial class receive_emai_form : DevExpress.XtraEditors.XtraForm
    {
        Reveivemailclass rm = new Reveivemailclass();
        MySqlConnection connection;
        public receive_emai_form()
        {
            InitializeComponent();
            
        }
        public void conopen()
        {
            string connectionString;
            connectionString = "SERVER=" + "localhost" + ";" + "DATABASE=" +
            "emailclient" + ";" + "UID=" + "root" + ";" + "PASSWORD=" + "Zhu19971125123!" + ";";
            connection = new MySqlConnection(connectionString);
            connection.Open();
        }
        public MySqlDataReader getinfo()
        {
            conopen();
            //确保Recipient正确
            String sql = "select Sender,Recipient,Subject from receive_email where Recipient = '<" + login.emailaddress + ">'" ;
            //"VALUES('" + oMail.From.ToString() + "','" + oMail.To[0].ToString() + "','" + subject + "')";

            MySqlCommand cmd = new MySqlCommand(sql, connection);

            MySqlDataReader data = cmd.ExecuteReader();

            return data;

        }

        private void receive_emai_form_Load(object sender, EventArgs e)
        {

            this.GridControl.DataSource = getinfo();
            connection.Close();

            Label_totalemail2.Text = rm.show_receviemial_num(login.emailaddress, login.password);
            Label_unreademail2.Text = rm.show_newreceviemial_num(login.emailaddress, login.password);
        }

        //renew
        private void simpleButton2_Click(object sender, EventArgs e)
        {

            Label_totalemail2.Text = rm.show_receviemial_num(login.emailaddress, login.password);
            Label_unreademail2.Text = rm.show_newreceviemial_num(login.emailaddress, login.password);
            rm.save_receivemail(login.emailaddress, login.password);
            this.GridControl.DataSource = getinfo();
            connection.Close();
        }

        private void Label_totalemail_Click(object sender, EventArgs e)
        {

        }

        private void simpleButton1_Click(object sender, EventArgs e)
        {
            //show sendclient
            SendClient Sc = new SendClient();
            Sc.ShowDialog();
        }

        private void repositoryItemButtonEdit1_ButtonClick(object sender, DevExpress.XtraEditors.Controls.ButtonPressedEventArgs e)
        {
            XtraMessageBox.Show(gridView1.GetFocusedRow().ToString());
        }

        private void repositoryItemButtonEdit4_ButtonClick(object sender, DevExpress.XtraEditors.Controls.ButtonPressedEventArgs e)
        {
            //事件中获取行对象核心代码：
            int rowIndex = gridView1.FocusedRowHandle;
            //XtraMessageBox.Show(gridView1.GetRowCellDisplayText(rowIndex, "Subject").ToString());
            Content_form CF = new Content_form();
            String sender1= gridView1.GetRowCellDisplayText(rowIndex, "Sender").ToString();
            String recipient1 = gridView1.GetRowCellDisplayText(rowIndex, "Recipient").ToString();
            String subject = gridView1.GetRowCellDisplayText(rowIndex, "Subject").ToString();
            CF.labelControl_s.Text = "sender:   " + sender1;
            CF.labelControl_r.Text = "recipient:   " + recipient1;
            CF.labelControl_subject.Text = "Subject:   " + subject;

            //Open database
            conopen();
            String sqll = "select Body from receive_email where Sender='" + sender1 + "'and Recipient='" + recipient1 + "' and Subject='"+ subject +"'";
            MySqlCommand cmd = new MySqlCommand(sqll, connection);
            MySqlDataReader sqlDataReader = cmd.ExecuteReader();
            // need to read first then get the information. Fangzheng
            sqlDataReader.Read();
            String Body = sqlDataReader["Body"].ToString();
            if (sqlDataReader.HasRows)
            {
                CF.textBox_receive.Text = "Body:   \r\n" + Body;

                connection.Close();

            }
            else
            {
                connection.Close();

            }
            CF.ShowDialog();
        }

    }
}

三级标题

4. 主界面整合

三级标题

5. 其他功能实现