C# WinForm 使用SMTP协议发送QQ邮箱验证码

文章来自：https://blog.csdn.net/IT_xiao_guang_guang/article/details/104336604

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前言

  在程序设计中，发送验证码是常见的一个功能，用户在注册账号或忘记密码时，通常需要发送验证码到手机或邮箱来验证身份，此篇博客介绍在C#WinForm中使用SMTP协议发送QQ邮箱验证码（其他邮箱方法类似）。
  关于"发送手机验证码"，可以参考我这篇文章：使用SMS接口发送手机验证码

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功能实现步骤

一、获取QQ邮箱授权码

授权码就是一个QQ邮箱推出的、长度为16位的、用于登录第三方客户端的专用密码。

  获取QQ邮箱授权码的方法

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二、功能界面

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三、创建发送邮箱验证码的类

QQ邮箱的SMTP使用了SSL加密，必须启用SSL加密，并且指定端口才能发送。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
//发送邮件需要引用的命名空间
using System.Net.Mail;
using System.Net;
using System.Text.RegularExpressions;
using System.Windows.Forms;

namespace MailVeriCode
{
    public class MailVeriCodeClass
    {
        #region  邮箱验证码功能
        /// <summary>
        ///  生成随机验证码
        /// </summary>
        /// <param name="CodeLength">验证码长度</param>
        public static string CreateRandomMailCode(int CodeLength)
        {
            int randNum;
            char code;
            string randomCode = String.Empty;//随机验证码

            //生成一定长度的随机验证码       
            //Random random = new Random();//生成随机数对象
            for (int i = 0; i < CodeLength; i++)
            {
                //利用GUID生成6位随机数      
                byte[] buffer = Guid.NewGuid().ToByteArray();//生成字节数组
                int seed = BitConverter.ToInt32(buffer, 0);//利用BitConvert方法把字节数组转换为整数
                Random random = new Random(seed);//以生成的整数作为随机种子
                randNum = random.Next();

                //randNum = random.Next();                
                if (randNum % 3 == 1)
                {
                    code = (char)('A' + (char)(randNum % 26));//随机大写字母
                }
                else if (randNum % 3 == 2)
                {
                    code = (char)('a' + (char)(randNum % 26));//随机小写字母
                }
                else
                {
                    code = (char)('0' + (char)(randNum % 10));//随机数字
                }
                randomCode += code.ToString();
            }
            return randomCode;
        }


        /// <summary>
        ///  发送邮件验证码
        /// </summary>
        /// <param name="MyEmailAddress">发件人邮箱地址</param>
        /// <param name="RecEmailAddress">收件人邮箱地址</param>
        /// <param name="Subject">邮件主题</param>
        /// <param name="MailContent">邮件内容</param>
        /// <param name="AuthorizationCode">邮箱授权码</param>
        /// <returns></returns>
        public static bool SendMailMessage(string MyEmailAddress, string RecEmailAddress, string Subject, string Body, string AuthorizationCode)
        {

            MailMessage mail = new MailMessage();
            mail.From = new MailAddress(MyEmailAddress);//发件人邮箱地址
            mail.To.Add(new MailAddress(RecEmailAddress));//收件人邮箱地址
            mail.Subject = Subject;//邮件标题
            mail.Body = Body;  //邮件内容  
            mail.Priority = MailPriority.High;//优先级

            SmtpClient client = new SmtpClient();//qq邮箱:smtp.qq.com；126邮箱:smtp.126.com              
            client.Host = "smtp.qq.com";
            client.Port = 587;//SMTP端口465或587
            client.EnableSsl = true;//使用安全加密SSL连接  
            client.DeliveryMethod = SmtpDeliveryMethod.Network;
            client.Credentials = new NetworkCredential(MyEmailAddress, AuthorizationCode);//验证发件人身份(发件人邮箱，邮箱授权码);                   
            
            try
            {
                client.Send(mail);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "发送失败", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return false;
            }
            return true;
        }


        /// <summary>
        ///  验证QQ邮箱
        /// </summary>
        /// <param name="mail">邮箱</param>
        /// <returns></returns>
        public static bool CheckMail(string mail)
        {
            string str = @"^[1-9][0-9]{4,}@qq.com$";
            Regex mReg = new Regex(str);

            if (mReg.IsMatch(mail))
            {
                return true;
            }
            return false;
        }
        #endregion
    }
}

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四、在From1中调用类中的函数，实现功能

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;
//需要引用的命名空间
using System.Net.Mail;
using System.Net;

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


        /// <summary>
        ///  发送邮箱验证码
        /// </summary>    
        int seconds1 = 60;//倒计时60s
        int seconds2 = 60 * 5;//验证码有效时间5分钟
        string strMailVeriCode;   
        private void btnMailVeriCode_Click(object sender, EventArgs e)
        {
            string recEMailAddress = txtMail.Text.Trim();//收件人邮箱             

            strMailVeriCode = MailVeriCodeClass.CreateRandomMailCode(6);
            string strBody = "验证码：" + strMailVeriCode + "，5分钟内有效,请勿泄漏于他人。如非本人操作，请忽略。系统邮件请勿回复。";//邮件内容            
            string strSubject = "【代码科技】注册验证";//邮件标题
            string strMyEmailAddress = "XXXXXXX";//发件人邮箱
            string strAuthorizationCode = "XXXXXX";//邮箱授权码

            if (string.IsNullOrEmpty(recEMailAddress))//判断是否输入了邮箱
            {
                MessageBox.Show("请输入邮箱！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                txtMail.Focus();
            }
            else if (MailVeriCodeClass.CheckMail(recEMailAddress) == false)//判断邮箱格式是否正确
            {
                MessageBox.Show("您输入的QQ邮箱有误，请重新输入！", "警告", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
                txtMail.Focus();
                return;
            }
            else//发送验证码
            {                
                //发送
                if (MailVeriCodeClass.SendMailMessage(strMyEmailAddress, recEMailAddress, strSubject, strBody, strAuthorizationCode) == true)
                {
                    btnMailVeriCode.Enabled = false;

                    //计时器初始化              
                    timer1.Interval = 1000;
                    timer1.Start();
                    timer2.Interval = 1000;
                    timer2.Start();                    

                }
                else
                {               
                    txtMail.Focus();
                }
            }
        }


        /// <summary>
        ///  倒计时—邮箱验证码1分钟只能点击发送1次
        /// </summary> 
        private void timer1_Tick(object sender, EventArgs e)
        {
            if (seconds1 > 0)
            {
                seconds1--;
                btnMailVeriCode.Text = "剩余" + seconds1.ToString() + "秒";
            }
            else
            {
                timer1.Stop();

                btnMailVeriCode.Text = "获取验证码";
                btnMailVeriCode.Enabled = true;
            }
        }


        /// <summary>
        ///  手机SMS验证码5分钟内有效；但是如果有新的验证码出现,旧验证码就会失效        
        /// </summary>
        private void timer2_Tick(object sender, EventArgs e)
        {
            if (seconds2 == 0)
            {
                timer2.Stop();

                //旧的验证码过期,生成一个新的验证码
                strMailVeriCode = MailVeriCodeClass.CreateRandomMailCode(6);
            }
        }


        /// <summary>
        ///  确认邮箱验证码
        /// </summary>      
        private void btnConfirm_Click(object sender, EventArgs e)
        {
            string mailVeriCode = txtMailVeriCode.Text.Trim();//邮箱验证码  

            if (string.IsNullOrEmpty(mailVeriCode) == true)
            {
                MessageBox.Show("请输入验证码", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                txtMailVeriCode.Focus();
            }
            else if (mailVeriCode.ToLower() != strMailVeriCode.ToLower())//判断邮箱验证码是否输入正确；不区分字母大小写
            {
                MessageBox.Show("您输入的验证码有误！", "警告", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
                txtMailVeriCode.Focus();
                return;
            }
            else
            {
                MessageBox.Show("验证成功!");
            }
        }
    }
}

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参考文章：
https://blog.csdn.net/weixin_42449444/article/details/90722070