VB.NET
Force Quoted-Printable Encoding for Email

Demonstrates how to force the quoted-printable encoding for email.
Chilkat VB.NET Downloads

VB.NET
Dim success As Boolean = False

Dim email As New Chilkat.Email

email.Subject = "test"
email.From = "bob@example.com"
email.AddTo("Mary","mary@example.com")

' Add plain-text and HTML alternative bodies.
' Include some "=" chars so we can see the quoted-printable encoding when used..
email.AddPlainTextAlternativeBody("This is a test == Hello World!")
email.AddHtmlAlternativeBody("<html><body>This is a test == Hello World!</body></html>")

' Examine the MIME of the email to see that it does not use quoted-printable.
' (If the email contained non-usascii chars, it would automatically use quoted-printable.)
Dim mailman As New Chilkat.MailMan
Debug.WriteLine(mailman.RenderToMime(email))

' Here is the MIME before forcing quoted-printable.
' Notice the Content-Transfer-Encoding is "7bit" (not "quoted-printable")

' MIME-Version: 1.0
' Date: Tue, 29 Sep 2020 12:26:52 -0500
' Message-ID: <CF274FC0A2F82B98A05B7507DF7DFB966A2C0EB8@CHILKATSLICE>
' Content-Type: multipart/alternative;
'  boundary="------------080901080902080000030208"
' X-Priority: 3 (Normal)
' Subject: test
' From: bob@example.com
' To: Mary <mary@example.com>
' 
' --------------080901080902080000030208
' Content-Transfer-Encoding: 7bit
' Content-Type: text/plain; charset=us-ascii; format=flowed
' 
' This is a test == Hello World!
' --------------080901080902080000030208
' Content-Transfer-Encoding: 7bit
' Content-Type: text/html; charset=us-ascii
' 
' <html><body>This is a test == Hello World!</body></html>
' --------------080901080902080000030208--

Debug.WriteLine("----")

' To force quoted-printable, set the Content-Transfer-Encoding header.
' It will automatically propagate as needed to the MIME sub-parts.
email.AddHeaderField("Content-Transfer-Encoding","quoted-printable")
Debug.WriteLine(mailman.RenderToMime(email))

' MIME-Version: 1.0
' Date: Tue, 29 Sep 2020 12:26:52 -0500
' Message-ID: <F36B276E3A720FE5111D15CE9142C8909E1F5AB9@CHILKATSLICE>
' Content-Type: multipart/alternative;
'  boundary="------------080901080902080000030208"
' X-Priority: 3 (Normal)
' Subject: test
' From: bob@example.com
' To: Mary <mary@example.com>
' 
' --------------080901080902080000030208
' Content-Transfer-Encoding: quoted-printable
' Content-Type: text/plain; charset=us-ascii; format=flowed
' 
' This is a test =3D=3D Hello World!
' --------------080901080902080000030208
' Content-Transfer-Encoding: quoted-printable
' Content-Type: text/html; charset=us-ascii
' 
' <html><body>This is a test =3D=3D Hello World!</body></html>
' --------------080901080902080000030208--