asp.net邮件添加答复

我如何才能添加一个不同的电子邮件然后发件人在 ReplayTo 似乎 MailMessage.ReplyTo 已弃用,所以我尝试使用 ReplyToList 相反。

但它告诉我

Property or indexer 'System.Net.Mail.MailMessage.ReplyToList' cannot be assigned to -- it is read only

以下是我目前的代码:

var reply = new MailAddressCollection();
 reply.Add("test@test.com");
 MailMessage mail = new MailMessage(senderEmail,usr.Email,"subject","message");
 mail.ReplyToList = reply;
 var smtp = new SmtpClient();
 smtp.Send(mail);