使用 .NET MailMessage 将 Content-Transfer-Encoding 设置为 Quoted-printable

Question

当我使用 .NET SmtpClient 发送邮件时，当我检查邮件的源代码时，我注意到内容传输编码设置为 base64。

我需要将其设置为可引用打印。我怎样才能做到这一点？提前致谢

public virtual MailMessage GetMailMessage(string body, string from, string [] user_emails, string [] back_office_emails, string subject)
{             
    MailMessage message = new MailMessage();
    message.IsBodyHtml = true;
    message.From = new MailAddress(from);            
    foreach (string email in user_emails)
    {
        message.To.Add(new MailAddress(email));
    }            
    if (back_office_emails != null)
    {
        foreach (string email in back_office_emails)
        {
            message.Bcc.Add(new MailAddress(email));
        }
    }
    message.Subject = subject;
    message.Body = body;
    message.BodyEncoding = System.Text.Encoding.UTF8;
    return message;
}

protected virtual void SendEmailTemplate(string body, string from, string[] user_emails, string[] back_office_emails, string subject)
{
    MailMessage message = GetMailMessage(body, from, user_emails, back_office_emails, subject);
    SmtpClient client = new SmtpClient(ConfigurationManager.AppSettings["SmtpClient"]);
    client.Send(message);
}

Answer 1

因为您将 message.BodyEncoding 设置为 System.Text.Encoding.UTF8，传输编码会自动设置为 Base64。 (source in remarks section)

根据您需要 Quoted-printable 传输编码的原因，您需要相应地调整 MailMessage 对象以将传输编码设置为 Quoted-printable。

可以多读书here

Answer 2

解决方案：

AlternateView plainTextView = AlternateView.CreateAlternateViewFromString(body.Trim(), new ContentType("text/html; charset=UTF-8"));
plainTextView.TransferEncoding = System.Net.Mime.TransferEncoding.QuotedPrintable;
message.AlternateViews.Add(plainTextView);

Answer 3

使用 .NET 4.5 或更高版本时，应该可以使用

message.BodyTransferEncoding = System.Net.Mime.TransferEncoding.QuotedPrintable;

见https://docs.microsoft.com/en-us/dotnet/api/system.net.mail.mailmessage.bodytransferencoding?view=netframework-4.5

使用 .NET MailMessage 将 Content-Transfer-Encoding 设置为 Quoted-printable

Set Content-Transfer-Encoding to Quoted-printable with .NET MailMessage

.net

c#

smtpclient