MailMessage objMailMessage= new MailMessage();
objMailMessage.Attachments.Add( objMailAttachment );//將附件附加到郵件消息對象中

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Net;
using System.Net.Mail;
using System.Text;

public class SendMail
...{
    public SendMail()
    ...{
    }
    private string _host;
    /**//// <summary>
    /// 服務(wù)器地址
    /// </summary>
    public string Host
    ...{
        get ...{ return _host; }
        set ...{ _host = value; }
    }
    private int _port;
    /**//// <summary>
    /// 服務(wù)器端口
    /// </summary>
    public int Port
    ...{
        get ...{ return _port; }
        set ...{ _port = value; }
    }
    private string _smtpUsername;
    /**//// <summary>
    /// 發(fā)送人郵箱用戶名
    /// </summary>
    public string SmtpUsername
    ...{
        get ...{ return _smtpUsername; }
        set ...{ _smtpUsername = value; }
    }
    private string _sendemail;
    /**//// <summary>
    /// 發(fā)送人郵箱帳號（只接收加密串，發(fā)郵件時(shí)解密）
    /// </summary>
    public string SendEmail
    ...{
        get
        ...{
            return _sendemail;
        }
        set ...{ _sendemail = value; }
    }
    private string _replyToEmail;
    /**//// <summary>
    /// 回復(fù)人郵箱賬號
    /// </summary>
    public string ReplyToEmail
    ...{
        get ...{ return _replyToEmail; }
        set ...{ _replyToEmail = value; }
    }
    private string _replyUserName;
    /**//// <summary>
    /// 回復(fù)人用戶名
    /// </summary>
    public string ReplyUserName
    ...{
        get ...{ return _replyUserName; }
        set ...{ _replyUserName = value; }
    }
    private string _getemail;
    /**//// <summary>
    /// 收件人郵箱帳號
    /// </summary>
    public string GetEmail
    ...{
        get ...{ return _getemail; }
        set ...{ _getemail = value; }
    }
    private string _smtpPassword;
    /**//// <summary>
    /// 發(fā)送人郵箱密碼（只接收加密串，發(fā)郵件時(shí)解密）
    /// </summary>
    public string SmtpPassword
    ...{
        get ...{ return _smtpPassword; }
        set ...{ _smtpPassword = value; }
    }
    private string _content;
    /**//// <summary>
    /// 郵件內(nèi)容
    /// </summary>
    public string Content
    ...{
        get ...{ return _content; }
        set ...{ _content = value; }
    }
    private string _title;
    /**//// <summary>
    /// 郵件標(biāo)題
    /// </summary>
    public string Title
    ...{
        get ...{ return _title; }
        set ...{ _title = value; }
    }
    private string[] _cc = null;
    /**//// <summary>
    /// 抄送郵箱
    /// </summary>
    public string[] cc
    ...{
        get ...{ return _cc; }
        set ...{ _cc = value; }
    }
    private string[] _bcc = null;
    /**//// <summary>
    /// 密送郵箱
    /// </summary>
    public string[] bcc
    ...{
        get ...{ return _bcc; }
        set ...{ _bcc = value; }
    }
    /**//// <summary>
    ///發(fā)送郵件
    /// </summary>
    /// <returns>返回是否成功</returns>
    public bool Send()
    ...{
        try
        ...{
            MailMessage objMailMessage;
            objMailMessage = new MailMessage(SendEmail, _getemail, _title, _content);
            if (!string.IsNullOrEmpty(_replyToEmail) && !string.IsNullOrEmpty(_replyUserName))
            ...{
                MailAddress reply = new MailAddress(_replyToEmail, _replyUserName);
                objMailMessage.ReplyToList.Add(reply);
            }
            objMailMessage.BodyEncoding = Encoding.GetEncoding(936);
            objMailMessage.IsBodyHtml = true;
            if (cc != null && cc.Length > 0)
            ...{
                foreach (string ccAddress in cc)
                ...{
                    objMailMessage.CC.Add(new MailAddress(ccAddress));
                }
            }
            if (bcc != null && bcc.Length > 0)
            ...{
                foreach (string bccAddress in bcc)
                ...{
                    objMailMessage.Bcc.Add(new MailAddress(bccAddress));
                }
            }
            SmtpClient client = new SmtpClient(this._host, this._port);
            if (!String.IsNullOrEmpty(this.SmtpUsername) && !String.IsNullOrEmpty(this.SmtpPassword))
            ...{
                client.Credentials = new NetworkCredential(this.SmtpUsername, this.SmtpPassword);
            }
            client.EnableSsl = false;
            client.Send(objMailMessage);
            objMailMessage.Dispose();
            return true;
        }
        catch
        ...{
            return false;
        }
    }
}

         //核心代碼開始
         using System.Web.Mail;
         MailMessage objMailMessage;
         MailAttachment objMailAttachment;
         // 創(chuàng)建一個(gè)附件對象
         objMailAttachment = new MailAttachment( "d:\test.txt" );//發(fā)送郵件的附件
         // 創(chuàng)建郵件消息
         objMailMessage = new MailMessage();
         objMailMessage.From = "mysina@sina.com";//源郵件地址
         objMailMessage.To = "scucj@126.com";//目的郵件地址，也就是發(fā)給我哈
         objMailMessage.Subject = "郵件發(fā)送標(biāo)題：你好";//發(fā)送郵件的標(biāo)題
         objMailMessage.Body = "郵件發(fā)送標(biāo)內(nèi)容：測試一下是否發(fā)送成功！";//發(fā)送郵件的內(nèi)容
         objMailMessage.Attachments.Add( objMailAttachment );//將附件附加到郵件消息對象中
         //SMTP地址
         SmtpMail.SmtpServer = "192.168.1.100";
         //開始發(fā)送郵件
         SmtpMail.Send( objMailMessage );