C#使用系统方法发送异步邮件完整实例

/******************************************************************
 * 创建人：HTL
 * 说明：C# 发送异步邮件Demo
 *******************************************************************/
using System;
using System.Net.Mail;
namespace SendAsyncEmailTest
{
  class Program
  {
    const string dateFormat = "yyyy-MM-dd :HH:mm:ss:ffffff";
    static void Main(string[] args)
    {
      Console.WriteLine("开始异步发送邮件,时间:" + DateTime.Now.ToString(dateFormat));
      new MailHelper().SendAsync("Send Async Email Test", "This is Send Async Email Test", "huangyuan413026@163.com", emailCompleted);
      Console.WriteLine("邮件正在异步发送,时间:" + DateTime.Now.ToString(dateFormat));
      Console.ReadKey();
      Console.WriteLine();
    }
    /// <summary>
    /// 邮件发送后的回调方法
    /// </summary>
    /// <param name="message"></param>
    static void emailCompleted(string message)
    {
      //延时1秒
      System.Threading.Thread.Sleep(1000);
      Console.WriteLine();
      Console.WriteLine("邮件发送结果:\r\n" + (message == "true" ? "邮件发送成功" : "邮件发送失败") + ",时间:" + DateTime.Now.ToString(dateFormat));
      //写入日志
    }
  }
  /// <summary>
  /// 发送邮件类
  /// </summary>
  public class MailHelper
  {
    public delegate int MethodDelegate(int x, int y);
    private readonly int smtpPort = 25;
    readonly string SmtpServer = "smtp.baidu.com";
    private readonly string UserName = "support@baidu.com";
    readonly string Pwd = "baidu.com";
    private readonly string AuthorName = "BaiDu";
    public string Subject { get; set; }
    public string Body { get; set; }
    public string Tos { get; set; }
    public bool EnableSsl { get; set; }
    MailMessage GetClient
    {
      get
      {
        if (string.IsNullOrEmpty(Tos)) return null;
        MailMessage mailMessage = new MailMessage();
        //多个接收者
        foreach (string _str in Tos.Split(','))
        {
          mailMessage.To.Add(_str);
        }
        mailMessage.From = new System.Net.Mail.MailAddress(UserName, AuthorName);
        mailMessage.Subject = Subject;
        mailMessage.Body = Body;
        mailMessage.IsBodyHtml = true;
        mailMessage.BodyEncoding = System.Text.Encoding.UTF8;
        mailMessage.SubjectEncoding = System.Text.Encoding.UTF8;
        mailMessage.Priority = System.Net.Mail.MailPriority.High;
        return mailMessage;
      }
    }
    SmtpClient GetSmtpClient
    {
      get
      {
        return new SmtpClient
        {
          UseDefaultCredentials = false,
          Credentials = new System.Net.NetworkCredential(UserName, Pwd),
          DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network,
          Host = SmtpServer,
          Port = smtpPort,
          EnableSsl = EnableSsl,
        };
      }
    }
    //回调方法
    Action<string> actionSendCompletedCallback = null;
    ///// <summary>
    ///// 使用异步发送邮件
    ///// </summary>
    ///// <param name="subject">主题</param>
    ///// <param name="body">内容</param>
    ///// <param name="to">接收者,以,分隔多个接收者</param>
    //// <param name="_actinCompletedCallback">邮件发送后的回调方法</param>
    ///// <returns></returns>
    public void SendAsync(string subject, string body, string to, Action<string> _actinCompletedCallback)
    {
      if (string.IsNullOrEmpty(to)) return;
      Tos = to;
      SmtpClient smtpClient = GetSmtpClient;
      MailMessage mailMessage = GetClient;
      if (smtpClient == null || mailMessage == null) return;
      Subject = subject;
      Body = body;
      EnableSsl = false;
      //发送邮件回调方法
      actionSendCompletedCallback = _actinCompletedCallback;
      smtpClient.SendCompleted += new SendCompletedEventHandler(SendCompletedCallback);
      try
      {
        smtpClient.SendAsync(mailMessage, "true");//异步发送邮件,如果回调方法中参数不为"true"则表示发送失败
      }
      catch (Exception e)
      {
        throw new Exception(e.Message);
      }
      finally
      {
        smtpClient = null;
        mailMessage = null;
      }
    }
    /// <summary>
    /// 异步操作完成后执行回调方法
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void SendCompletedCallback(object sender, System.ComponentModel.AsyncCompletedEventArgs e)
    {
      //同一组件下不需要回调方法,直接在此写入日志即可
      //写入日志
      //return;
      if (actionSendCompletedCallback == null) return;
      string message = string.Empty;
      if (e.Cancelled)
      {
        message = "异步操作取消";
      }
      else if (e.Error != null)
      {
        message = (string.Format("UserState:{0},Message:{1}", (string)e.UserState, e.Error.ToString()));
      }
      else
        message = (string)e.UserState;
      //执行回调方法
      actionSendCompletedCallback(message);
    }
  }
}