C#通过邮箱验证来找回密码

                 本文链接：[https://blog.csdn.net/weixin\_42449444/article/details/90722070](https://blog.csdn.net/weixin_42449444/article/details/90722070) 

public static string CreateRandomCode(int length)  //生成由数字和大小写字母组成的验证码
{
    string list = "qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM1234567890";  
    //list中存放着验证码的元素
    Random random = new Random();
    string code = "";   //验证码
    for (int i = 0; i < length; i++)   //循环6次得到一个伪随机的六位数验证码
    {
        code += list[random.Next(0, list.Length - 1)];
    }
    return code;
}

using System.Net;
using System.Net.Mail;

MailMessage mail = new MailMessage();  //实例化一个邮件类
mail.From = new MailAddress("(发件人邮箱地址)");   //发件人邮箱地址
mail.To.Add(new MailAddress("(收件人邮箱地址)"));    //收件人邮箱地址
mail.Subject = "(邮件标题)";    //邮件标题
mail.Body = "(邮件内容)";  //邮件内容          
SmtpClient client = new SmtpClient("smtp.qq.com");   //实例化一个SmtpClient类
client.EnableSsl = true;    //使用安全加密连接
client.Credentials = new NetworkCredential("(发件人邮箱)", "(邮箱授权码)");//验证发件人身份(发件人邮箱，邮箱授权码);
client.Send(mail);  //发送邮件
MessageBox.Show("发送成功！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);

private void Button_Click(object sender, EventArgs e)   //发送邮箱验证码
{
    string userid = textBox1.Text.Trim();   //账号
    string email = textBox2.Text.Trim();    //邮箱
    if (!String.IsNullOrEmpty(userid)&&!String.IsNullOrEmpty(email))  //账号、邮箱非空
    {
        SqlConnection connection = new SqlConnection("Data Source=.;Initial Catalog=Library;User ID=sa;Password=sql123");
        connection.Open();
        SqlCommand command = new SqlCommand("SELECT username,email FROM login_table WHERE username='" + userid + "' AND email='" + email + "'", connection);
        SqlDataReader data = command.ExecuteReader();
        if (data.HasRows)   //若输入的电子邮箱是账号注册时填写的邮箱
        {
            try
            {
                MailMessage mail = new MailMessage();  //实例化一个发送邮件类
                mail.From = new MailAddress("tanyaodan@qq.com");   //发件人邮箱地址
                mail.To.Add(new MailAddress(email));    //收件人邮箱地址
                mail.Subject = "【HBU图书管理系统】找回密码";    //邮件标题
                code = Program.CreateRandomCode(6);   //生成伪随机的6位数验证码
                mail.Body = "验证码是: " + code + "，请在5分钟内进行验证。验证码提供给他人可能导致账号被盗，请勿泄露，谨防被骗。系统邮件请勿回复。";  //邮件内容          
                SmtpClient client = new SmtpClient("smtp.qq.com");   //实例化一个SmtpClient类。
                client.EnableSsl = true;    //使用安全加密连接
                client.Credentials = new NetworkCredential("tanyaodan@qq.com", "(16位授权码不能泄露)");//验证发件人身份(发件人的邮箱，邮箱里的生成授权码);        
                client.Send(mail);
                //计时器初始化
                cnt1 = 60;
                cnt2 = 300;
                timer1.Enabled = true;   //time1用来记录1分钟
                timer2.Enabled = true;   //time2用来记录5分钟
                button.Enabled = false;  //发送按钮不可点击
                //MessageBox.Show("发送成功！");
            }
            catch
            {
               MessageBox.Show("发送失败！\n请检查邮箱是否输入有误。", "", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }
        else
        {
            MessageBox.Show("该邮箱不是账号绑定的邮箱。", "失败", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }
    }
    else
    {
        MessageBox.Show("请将账号和邮箱填写完整！", "警告", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
    }
}

private void Timer1_Tick(object sender, EventArgs e)    //发送完邮件,需要60秒后才能再次发送邮件
{
    if (cnt1 > 0)
    {
        cnt1--;
        button.Text = "发送(" + cnt1 + ")";
    }
    else
    {
        timer1.Enabled = false;
        button.Enabled = true;
        button.Text = "发送";
    }
}

private void Timer2_Tick(object sender, EventArgs e)    //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GG
{
    if (cnt2 == 0)
    {
        timer2.Enabled = false;
        code = Program.CreateRandomCode(6);    //旧的验证码过期,生成一个新的验证码
    }
}

if (textBox.Text.ToLower() != code.ToLower())   //若验证码输入错误
{
    MessageBox.Show("您输入的验证码有误！", "警告", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
}
else   //验证成功
{
    MessageBox.Show("验证成功！","提示",MessageBoxButtons.OK,MessageBoxIcon.Information);
}