如何通过需要验证的邮件服务器发送邮件？

.net1.1下
System.Web.Mail.SmtpMail.Send
调用了内部方法: SmtpMail.CdoSysHelper.Send(message);


CdoSysHelper.Send的内部方法实现为:

if ((text2 != null) || (message.Fields.Count > 0))
{
object obj4 = SmtpMail.LateBoundAccessHelper.GetPropStatic(obj1, "Configuration");
if (obj4 != null)
{
if (text2 != null)
{
SmtpMail.LateBoundAccessHelper.SetPropStatic(obj4, "Fields", "http://schemas.microsoft.com/cdo/configuration/sendusing", 2);
SmtpMail.LateBoundAccessHelper.SetPropStatic(obj4, "Fields", "http://schemas.microsoft.com/cdo/configuration/smtpserver", text2);
SmtpMail.LateBoundAccessHelper.SetPropStatic(obj4, "Fields", "http://schemas.microsoft.com/cdo/configuration/smtpserverport", 0x19);
}
foreach (DictionaryEntry entry1 in message.Fields)
{
SmtpMail.LateBoundAccessHelper.SetPropStatic(obj4, "Fields", (string) entry1.Key, entry1.Value);
}
object obj5 = SmtpMail.LateBoundAccessHelper.GetPropStatic(obj4, "Fields");
SmtpMail.LateBoundAccessHelper.CallMethodStatic(obj5, "Update", new object[0]);
Marshal.ReleaseComObject(obj5);
Marshal.ReleaseComObject(obj4);
}
}

因为如下的信息:
foreach (DictionaryEntry entry1 in message.Fields)
{
SmtpMail.LateBoundAccessHelper.SetPropStatic(obj4, "Fields", (string) entry1.Key, entry1.Value);
}

[/code]
故我们可以自己添加相关的CDO属性:
如使用需要认证的SMTP SERVER,则我们可以加入

MailMessage myMail = new MailMessage();
myMail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusername",userName);
myMail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendpassword",password);

这样就达到了认证的效果.

例子代码如下:

MailMessage myMail = new MailMessage();
        myMail.From = emailFrom;
        myMail.To = emailTo;
        myMail.Subject = subject;
        myMail.Body = sb.ToString();
        myMail.BodyFormat = MailFormat.Html;
        myMail.Fields.Add(" http://schemas.microsoft.com/cdo/configuration/sendusing","2");

        //发送地址，有的邮件服务器会做检验，最好加上
        myMail.Fields.Add(" http://schemas.microsoft.com/cdo/configuration/sendemailaddress",emailFrom);
        myMail.Fields.Add(" http://schemas.microsoft.com/cdo/configuration/smtpuserreplyemailaddress",emailFrom);
        //SMTP帐户名称
        myMail.Fields.Add(" http://schemas.microsoft.com/cdo/configuration/smtpaccountname",userName);
        //验证用户名
        myMail.Fields.Add(" http://schemas.microsoft.com/cdo/configuration/sendusername",Your 163.com'suserName);
        //验证密码
        myMail.Fields.Add(" http://schemas.microsoft.com/cdo/configuration/sendpassword",your 163.com'spassword);
       
        //验证方式，0为匿名不需要验证，1为basic (clear text)验证方式，2为NTLM验证方式
        myMail.Fields.Add(" http://schemas.microsoft.com/cdo/configuration/smtpauthenticate","1");
        //SMTP服务器地址，也可以在后面指定
        myMail.p.Add(" http://schemas.microsoft.com/cdo/configuration/smtpserver","smtp.163.com");
        //SmtpMail.SmtpServer = "smtp.163.com";

        //邮件内容为文本还是HTML
        myMail.Body = Web.Mail.MailFormat.Html;
        //邮件级别
        myMail.Priority = Web.Mail.MailPriority.High;
        //SmtpMail.SmtpServer = "smtp.163.com";
        SmtpMail.Send(myMail);

附CdoConfiguration相关属性参考:

public abstract class CdoConfiguration
{
// Fields
[MarshalAs(UnmanagedType.BStr)]
public const string cdoAutoPromoteBodyParts = "http://schemas.microsoft.com/cdo/configuration/autopromotebodyparts";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoFlushBuffersOnWrite = "http://schemas.microsoft.com/cdo/configuration/flushbuffersonwrite";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoHTTPCookies = "http://schemas.microsoft.com/cdo/configuration/httpcookies";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoLanguageCode = "http://schemas.microsoft.com/cdo/configuration/languagecode";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoNNTPAccountName = "http://schemas.microsoft.com/cdo/configuration/nntpaccountname";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoNNTPAuthenticate = "http://schemas.microsoft.com/cdo/configuration/nntpauthenticate";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoNNTPConnectionTimeout = "http://schemas.microsoft.com/cdo/configuration/nntpconnectiontimeout";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoNNTPServer = "http://schemas.microsoft.com/cdo/configuration/nntpserver";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoNNTPServerPickupDirectory = "http://schemas.microsoft.com/cdo/configuration/nntpserverpickupdirectory";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoNNTPServerPort = "http://schemas.microsoft.com/cdo/configuration/nntpserverport";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoNNTPUseSSL = "http://schemas.microsoft.com/cdo/configuration/nntpusessl";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoPostEmailAddress = "http://schemas.microsoft.com/cdo/configuration/postemailaddress";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoPostPassword = "http://schemas.microsoft.com/cdo/configuration/postpassword";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoPostUserName = "http://schemas.microsoft.com/cdo/configuration/postusername";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoPostUserReplyEmailAddress = "http://schemas.microsoft.com/cdo/configuration/postuserreplyemailaddress";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoPostUsingMethod = "http://schemas.microsoft.com/cdo/configuration/postusing";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoSaveSentItems = "http://schemas.microsoft.com/cdo/configuration/savesentitems";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoSendEmailAddress = "http://schemas.microsoft.com/cdo/configuration/sendemailaddress";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoSendPassword = "http://schemas.microsoft.com/cdo/configuration/sendpassword";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoSendUserName = "http://schemas.microsoft.com/cdo/configuration/sendusername";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoSendUserReplyEmailAddress = "http://schemas.microsoft.com/cdo/configuration/senduserreplyemailaddress";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoSendUsingMethod = "http://schemas.microsoft.com/cdo/configuration/sendusing";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoSMTPAccountName = "http://schemas.microsoft.com/cdo/configuration/smtpaccountname";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoSMTPAuthenticate = "http://schemas.microsoft.com/cdo/configuration/smtpauthenticate";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoSMTPConnectionTimeout = "http://schemas.microsoft.com/cdo/configuration/smtpconnectiontimeout";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoSMTPServer = "http://schemas.microsoft.com/cdo/configuration/smtpserver";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoSMTPServerPickupDirectory = "http://schemas.microsoft.com/cdo/configuration/smtpserverpickupdirectory";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoSMTPServerPort = "http://schemas.microsoft.com/cdo/configuration/smtpserverport";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoSMTPUseSSL = "http://schemas.microsoft.com/cdo/configuration/smtpusessl";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoURLGetLatestVersion = "http://schemas.microsoft.com/cdo/configuration/urlgetlatestversion";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoURLProxyBypass = "http://schemas.microsoft.com/cdo/configuration/urlproxybypass";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoURLProxyServer = "http://schemas.microsoft.com/cdo/configuration/urlproxyserver";
[MarshalAs(UnmanagedType.BStr)]
public const string cdoUseMessageResponseText = "http://schemas.microsoft.com/cdo/configuration/usemessageresponsetext";
}

相关链接:
1. www.systemwebmail.com
2. http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemwebmail.asp

net2.0下

.net Framework 2.0 下，在 System.Net.Mail 命名空间中提供了对邮件操作的支持，他的功能更强大。比如你的邮件服务器需要验证才能发送邮件，代码就只需简单成如下：

public static void SendSMTPEMail(string strSmtpServer, string strFrom, string strFromPass, string strto, string strSubject, string strBody)
...{
    System.Net.Mail.SmtpClient client = new SmtpClient(strSmtpServer);
    client.UseDefaultCredentials = false;
    client.Credentials = new System.Net.NetworkCredential(strFrom, strFromPass);
    client.DeliveryMethod = SmtpDeliveryMethod.Network;
   
    System.Net.Mail.MailMessage message = new MailMessage(strFrom, strto, strSubject, strBody);
    message.BodyEncoding = System.Text.Encoding.UTF8;
    message.IsBodyHtml = true;

    client.Send(message);
}

我们可以通过修改 UseDefaultCredentials  Credentials  DeliveryMethod  等属性，方便的支持各种情况下发送邮件的方式。