SmtpClient发送邮件遭遇The specified string is not in the form required for a subject.

通过System.Net.Mail发送邮件，出现错误：

System.ArgumentException: The specified string is not in the form required for a subject. at System.Net.Mail.Message.set_Subject(String value) at System.Net.Mail.MailMessage.set_Subject(String value) 通过Reflector代码看到 System.Net.Mail.MailMessage 的Suject调用了内部方法MailBnfHelper.HasCROrLF internal string Subject { get { return this.subject; } set { if ((value != null) && MailBnfHelper.HasCROrLF(value)) { throw new ArgumentException(SR.GetString("MailSubjectInvalidFormat")); } this.subject = value; if (((this.subject != null) && (this.subjectEncoding == null)) && !MimeBasePart.IsAscii(this.subject, false)) { this.subjectEncoding = Encoding.GetEncoding("utf-8"); } } }

相应的解决方案是采用下述代码

message.Subject = subject.Replace('\r', ' ').Replace('\n', ' ')

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