最近要用C#實現用免費smtp伺服器（GMail）發郵件，貼段整理好的代碼

說明：本來打算用sina的，(smtp.sina.com) ，但經過測試，感覺這個非常不穩定，所以改用GMail的smtp服務，感覺非常穩定、快速。記錄下來，方便後來者！

Method 1
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// using System.Net.Mail;
Mailmessageage message = new Mailmessageage();
message.From = new MailAddress("User@gmail.com", "Your DisplayName");
message.To.Add(new MailAddress("To@gmail.com")); // the email you want to send email to
message.Subject = "A test email"

message.IsBodyHtml = true;
message.BodyEncoding = System.Text.Encoding.UTF8;
message.Body = "this is just a simple test!<br> Jack"
message.Priority = MailPriority.High;

SmtpClient client = new SmtpClient("smtp.gmail.com", 587); // 587;//Gmail使用的連接埠
client.Credentials = new System.Net.NetworkCredential("User@gmail.com", "*****"); // Your user name & password
client.EnableSsl = true; //經過ssl加密
object userState = message;
try
{
client.Send(message);
Response.Write("郵件發送到" + message.To.ToString() + "<br>");
}
catch (Exception ee)
{
Response.Write(ee.messageage + "<br>" + ee.InnerException.messageage);
}

Method 2
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// http://weblogs.asp.net/scottgu/archive/2005/12/10/432854.aspx
// using System.Net.Mail;
MailMessage message = new MailMessage();
message.From = new MailAddress("User@gmail.com");

message.To.Add(new MailAddress("to@gmail.com"));

message.Subject = "This is my subject"
message.Body = "This is the content"
SmtpClient client = new SmtpClient();
client.EnableSsl = true;

try
{
client.Send(message);
Response.Write("郵件發送到" + message.To.ToString() + "<br>");
}
catch (Exception ee)
{
Response.Write(ee.Message );
}

//In web.config

<system.net>
<mailSettings>
<smtp from="from@gmail.com">
<network host="smtp.gmail.com" port="587" userName="User@gmail.com" password="your pwd" />
<!-- if has 'defaultCredentials="true"' , using Gmail can not send success -->
</smtp>
</mailSettings>
</system.net>