用CDO.Message来发邮件

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Threading;
using System.IO;

namespace SendMail
{
    public partial class FormMain : Form
    {
        //用于发送邮件的线程
        Thread threadSending = null;
        //代表邮件的 CDO.Message对象
        CDO.Message oMsg = null;
        //邮件发送流
        ADODB.Stream msgStream = null;

        public FormMain()
        {
            InitializeComponent();
            Control.CheckForIllegalCrossThreadCalls = false;
        }

        private void button_Send_Click(object sender, EventArgs e)
        {
            if (this.threadSending != null && this.threadSending.IsAlive)
            {
                this.label_Info.ForeColor = Color.Red;
                this.label_Info.Text = "目前正有一邮件发送中";
                return;
            }
            else
            {
                ThreadStart ts = new ThreadStart(this.SendMail);
                this.threadSending = new Thread(ts);
                this.threadSending.Start();
            }
        }

        private void SendMail()
        {
            this.label_Info.ForeColor = Color.Blue;
            this.label_Info.Text = "正发送邮件“ " + this.textBox_Subject.Text + "”";

            try
            {
                this.oMsg = new CDO.Message();
                this.oMsg.From = this.textBox_Form.Text;
                this.oMsg.To = this.textBox_To.Text;
                this.oMsg.Subject = this.textBox_Subject.Text;
                this.oMsg.HTMLBody = "<html><body>" + this.richTextBox_MessageBody.Text + "</body></html>";

                //添加附件
                string file = this.textBox_Attachment.Text.Trim();
                if (!String.IsNullOrEmpty(file))
                {
                    if (System.IO.File.Exists(file))
                    {
                        this.oMsg.AddAttachment(file, "", "");
                    }
                    else
                    {
                        this.label_Info.ForeColor = Color.Red;
                        this.label_Info.Text = "添加的附件不存在，发送失败！";
                        return;
                    }
                }

CDO.IConfiguration iConfg = this.oMsg.Configuration;
ADODB.Fields oFields = iConfg.Fields;

                oFields["http://schemas.microsoft.com/cdo/configuration/sendusing"].Value = 2;
                oFields["http://schemas.microsoft.com/cdo/configuration/sendemailaddress"].Value = "32mid@zjjzx.mail"; //修改这里，并保持发件人与这里的地址一致
                oFields["http://schemas.microsoft.com/cdo/configuration/smtpaccountname"].Value = "32mid@zjjzx.mail"; //修改这里
                oFields["http://schemas.microsoft.com/cdo/configuration/sendusername"].Value = "32mid";//修改这里
                oFields["http://schemas.microsoft.com/cdo/configuration/sendpassword"].Value = "32mid";//修改这里
                oFields["http://schemas.microsoft.com/cdo/configuration/smtpauthenticate"].Value = 1;
                //value=0 代表Anonymous验证方式（不需要验证）
                //value=1 代表Basic验证方式（使用basic (clear-text) authentication.
                //The configuration sendusername/sendpassword or postusername/postpassword fields are used to specify credentials.）
                //Value=2 代表NTLM验证方式（Secure Password Authentication in Microsoft Outlook Express）
                oFields["http://schemas.microsoft.com/cdo/configuration/languagecode"].Value = 0x0804;
                oFields["http://schemas.microsoft.com/cdo/configuration/smtpserver"].Value = "192.168.0.111";

                oFields.Update();
                this.oMsg.BodyPart.Charset = "gb2312";
                this.oMsg.HTMLBodyPart.Charset = "gb2312";

                this.msgStream = this.oMsg.GetStream();
                this.timer_Sending.Start();

this.oMsg.Send();

                this.timer_Sending.Stop();
            }
            catch (Exception ex)
            {
                this.label_Info.ForeColor = Color.Red;
                this.label_Info.Text = "发送邮件“ " + this.textBox_Subject.Text + "” 失败:\n" + ex.Message;
                return;
            }

this.label_Info.ForeColor = Color.Green;
this.label_Info.Text = "已将邮件“ " + this.textBox_Subject.Text + " ” 发送至：" + this.textBox_To.Text;

oMsg = null;

}

        private void linkLabel_View_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
        {
            if (this.openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                this.textBox_Attachment.Text = this.openFileDialog1.FileName;
            }
        }

        private void linkLabel_AttachmentCanel_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
        {
            this.textBox_Attachment.Clear();
        }

        //监视发送邮件的进度
        private void timer_Sending_Tick(object sender, EventArgs e)
        {
            this.label_Info.ForeColor = Color.Blue;
            this.label_Info.Text = "正发送邮件“ " + this.textBox_Subject.Text + "”";

            if (this.msgStream != null)
            {
                //不正确的方法
                //this.label_Info.Text += this.msgStream.Position + "/" + this.msgStream.Size;
            }
        }

}
}

(这是我刚从网上找到的，还没来得急仔细琢磨，但发现能实现发邮件，用foxmail收到。不会发生乱码的问题，你可要仔细瞧勒！)