C#利用CDO.Message发送邮件

如何引用CDO.Message？ cod.message的引用位置： C:\Windows\System32\cdosys.dll

CDO.Message objMail = new CDO.Message(,2);
try
{
objMail.To = "接收邮件账号";
objMail.From = "发送邮件账号";
objMail.Subject = "subject";//邮件主题string strHTML = @"";
strHTML = strHTML + "这里可以填写html内容";
objMail.HTMLBody = strHTML;//邮件内容
objMail.Configuration.Fields["http://schemas.microsoft.com/cdo/configuration/smtpserverport"].Value = 465;//设置端口
objMail.Configuration.Fields["http://schemas.microsoft.com/cdo/configuration/smtpserver"].Value = "smtp.qq.com";
objMail.Configuration.Fields["http://schemas.microsoft.com/cdo/configuration/sendemailaddress"].Value = "发送邮件账号";
objMail.Configuration.Fields["http://schemas.microsoft.com/cdo/configuration/smtpuserreplyemailaddress"].Value = "发送邮件账号";
objMail.Configuration.Fields["http://schemas.microsoft.com/cdo/configuration/smtpaccountname"].Value = "发送邮件账号";
objMail.Configuration.Fields["http://schemas.microsoft.com/cdo/configuration/sendusername"].Value = "发送邮件账号";
objMail.Configuration.Fields["http://schemas.microsoft.com/cdo/configuration/sendpassword"].Value = "发送邮件账号登录密码";
objMail.Configuration.Fields["http://schemas.microsoft.com/cdo/configuration/sendusing"].Value = 2;
objMail.Configuration.Fields["http://schemas.microsoft.com/cdo/configuration/smtpauthenticate"].Value = 1;
objMail.Configuration.Fields["http://schemas.microsoft.com/cdo/configuration/smtpusessl"].Value = "true";//这一句指示是否使用ssl
objMail.Configuration.Fields.Update(,2);
objMail.Send(,2);
}
catch (Exception ex) { throw ex; }
finally { }
System.Runtime.InteropServices.Marshal.ReleaseComObject(objMail,2);
objMail = null;