在.NET中计算电子邮件的大小

using System.Net.Mail;

public static long CalculateEmailSize(MailMessage mailMessage)
{
    // 计算邮件主体的大小
    long bodySize = Encoding.UTF8.GetByteCount(mailMessage.Body);

    // 计算邮件主题的大小
    long subjectSize = Encoding.UTF8.GetByteCount(mailMessage.Subject);

    // 计算邮件发件人、收件人、抄送人和密送人的大小
    long fromSize = Encoding.UTF8.GetByteCount(mailMessage.From.ToString());
    long toSize = mailMessage.To.Sum(recipient => Encoding.UTF8.GetByteCount(recipient.ToString()));
    long ccSize = mailMessage.CC.Sum(recipient => Encoding.UTF8.GetByteCount(recipient.ToString()));
    long bccSize = mailMessage.Bcc.Sum(recipient => Encoding.UTF8.GetByteCount(recipient.ToString()));

    // 计算邮件中所有附件的大小
    long attachmentsSize = mailMessage.Attachments.Sum(attachment => attachment.ContentStream.Length);

    // 返回邮件总大小
    return bodySize + subjectSize + fromSize + toSize + ccSize + bccSize + attachmentsSize;
}