How to set content transfer encoding using MimeKit/MailKit?

Question

I try to send text in attachment. That works well only right now i have encoding problems in the builder.ToMessageBody() statement (see code below) Itry to send an email with text "my text = my subject and Version=1.0" as attachment, but when you open the email the text has been altered to "my text =3D my subject and Version=3D1.0". As you can see the = sign has been encoded to =3D Is there a way to change the encoding? Thanks

var message = new MimeMessage();
var builder = new BodyBuilder();

builder.TextBody = "";
var xmltext ="my text = my subject and Version=1.0" ;

builder.Attachments.Add("12345.txt", Encoding.ASCII.GetBytes(xmltext), new ContentType("text", "plain"));

message.Body = builder.ToMessageBody();

Answer 1

The Add method actually returns the MimeEntity that it creates, allowing you to make changes to it.

To force the encoding to base64, for example, you can do this:

var attachment = (MimePart) builder.Attachments.Add("12345.txt", Encoding.ASCII.GetBytes(xmltext), new ContentType("text", "plain"));
attachment.ContentTransferEncoding = ContentENcoding.Base64;