延迟在C#中发送电子邮件

using System;
using System.Net.Mail;
using System.Threading.Tasks;

class Program
{
    static async Task Main(string[] args)
    {
        await SendEmailAsync();
        Console.WriteLine("邮件发送成功！");
    }

    static async Task SendEmailAsync()
    {
        var mail = new MailMessage("sender@example.com", "recipient@example.com", "主题", "正文");
        var client = new SmtpClient("smtp.example.com", 587)
        {
            Credentials = new System.Net.NetworkCredential("username", "password"),
            EnableSsl = true
        };

        await client.SendMailAsync(mail);
    }
}

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

class Program
{
    static void Main(string[] args)
    {
        var timer = new Timer(SendEmail, null, 5000, Timeout.Infinite);
        Console.WriteLine("邮件将在5秒后发送...");
        Console.ReadLine();
    }

    static void SendEmail(object state)
    {
        var mail = new MailMessage("sender@example.com", "recipient@example.com", "主题", "正文");
        var client = new SmtpClient("smtp.example.com", 587)
        {
            Credentials = new System.Net.NetworkCredential("username", "password"),
            EnableSsl = true
        };

        client.Send(mail);
        Console.WriteLine("邮件发送成功！");
    }
}