C#实现简单邮件发送

using System;
using System.Text;
using System.Windows.Forms;
using System.Net.Mail;
using System.IO;
using System.Net;
using System.Net.Mime;
namespace SendMail
{
public partial class MainFrm : Form
{
public MainFrm()
{
InitializeComponent();
}
//保存附件名
public static string filename;
//窗体加载
private void MainFrm_Load(object sender, EventArgs e)
{
youbox.Text = "QQ.com";
hebox.Text = "QQ.com";
}
//添加附件
private void addfilebtn_Click(object sender, EventArgs e)
{
checkfile.ShowDialog();
filename = checkfile.FileName;
if (filename != "")
{
filelab.Visible = true;
filelab.Text = "当前附件(双击删除)：" + filename;
}
}
//删除附件
private void filelab_DoubleClick(object sender, EventArgs e)
{
filename = "";
filelab.Text = "当前附件：" + filename;
}
//发送邮件
private void sendbtn_Click(object sender, EventArgs e)
{
try
{
//实例发件人smtp客户端
SmtpClient client = new SmtpClient("smtp." + youbox.Text);
//生成发送地址
string strFrom = string.Empty;
if (youmailtxt.Text != "")
{
strFrom = youmailtxt.Text + "@" + youbox.Text;
}
else
{
MessageBox.Show("请输入你的邮箱地址！", "错误");
youmailtxt.Focus();
return;
}
//生成收件人地址
string strHe = string.Empty;
if (hemailtxt.Text != "")
{
strHe = hemailtxt.Text + "@" + hebox.Text;
}
else
{
MessageBox.Show("请输入收件人的邮箱地址！", "错误");
hemailtxt.Focus();
return;
}
//构造发收件人对象
MailAddress you = new MailAddress(strFrom, strFrom, Encoding.UTF8);
MailAddress he = new MailAddress(strHe, strHe, Encoding.UTF8);
//构造msb对象
MailMessage msg = new MailMessage(you, he);
//添加附件
if (File.Exists(filename))
{
//构造附件对象
Attachment mailfile = new Attachment(filename);
//得到文件信息
ContentDisposition disposition = mailfile.ContentDisposition;
// disposition.CreationDate = File.GetCreationTime(filename);
// disposition.ModificationDate = File.GetLastWriteTime(filename);
// disposition.ReadDate = File.GetLastAccessTime(filename);
//添加附件到msg
msg.Attachments.Add(mailfile);
}
//添加主题和内容
msg.Subject = titletxt.Text;
msg.SubjectEncoding = Encoding.UTF8;
msg.Body = contentbox.Text;
msg.BodyEncoding = Encoding.UTF8;
//设置邮件发送方式
client.DeliveryMethod = SmtpDeliveryMethod.Network;
msg.IsBodyHtml = false;
//给gmail开启ssl
if (youbox.Text == "gmail.com")
{
client.EnableSsl = true;
}
else
{
client.EnableSsl = false;
}
//设置用户名和密码
client.UseDefaultCredentials = false;
string username = youmailtxt.Text;
string passwd = passtxt.Text;
//用户登录信息
NetworkCredential mycre = new NetworkCredential(username, passwd);
client.Credentials = mycre;
//发送邮件
this.Hide();
client.Send(msg);
this.Visible = true;
MessageBox.Show("邮件成功发送到\"" + strHe + "\"!", "发送成功");
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}

}
}
}