c#调用qq邮箱smtp发送邮件(修改版)

try
{
    MailMessage mm = new MailMessage();
    MailAddress Fromma = new MailAddress("xxxx@qq.com");
    MailAddress Toma = new MailAddress("MMMMMMM@qq.com", null);
    mm.From = Fromma;
    //收件人
    mm.To.Add("MMMMMM@qq.com");
    //邮箱标题
    mm.Subject = "Hello Dear:";
    mm.IsBodyHtml = true;
    //邮件内容
    mm.Body = "你好Mr流星！";
    //内容的编码格式
    mm.BodyEncoding = System.Text.Encoding.UTF8;
    //mm.ReplyTo = Toma;
    //mm.Sender =Fromma;
    //mm.IsBodyHtml = false;
    mm.DeliveryNotificationOptions = DeliveryNotificationOptions.OnSuccess;
    mm.CC.Add(Toma);
    SmtpClient sc = new SmtpClient();
    NetworkCredential nc = new NetworkCredential();
    nc.UserName = "XXXXX@qq.com";//你的邮箱地址
    nc.Password = "zzzzz";//邮箱密码，xxxxx@qq.com邮箱的密码
       sc.UsedefaultCredentials = true;
    sc.DeliveryMethod = SmtpDeliveryMethod.Network;
    sc.Credentials = nc;
    //如果这里报mail from address must be same as authorization user这个错误，是QQ邮箱没有开启SMTP，
    //到自己邮箱设置。在帐户下面,如果是163邮箱，要修改为smtp.163.com
    sc.Host = "smtp.qq.com";
    sc.Send(mm);
}
catch (Exception ex)
{
    throw new Exception(ex.Message);
}