Delphi ActiveX
Force Quoted-Printable Encoding for Email

Demonstrates how to force the quoted-printable encoding for email.
Chilkat Delphi ActiveX Downloads

Delphi ActiveX
uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Integer;
email: TChilkatEmail;
mailman: TChilkatMailMan;

begin
success := 0;

email := TChilkatEmail.Create(Self);

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.)
mailman := TChilkatMailMan.Create(Self);
Memo1.Lines.Add(mailman.RenderToMime(email.ControlInterface));

// 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--

Memo1.Lines.Add('----');

// 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');
Memo1.Lines.Add(mailman.RenderToMime(email.ControlInterface));

// 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--
end;