SingleEmailMessage - send email to a recipient different from the record referenced by setTargetObjectId

Question

My code is as follows:

List<Messaging.SingleEmailMessage> emails = new List<Messaging.SingleEmailMessage>();
Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage ();
email.setTemplateId(templateId);
email.setSaveAsActivity(false);
email.setToAddresses('raytest1@domain.com');
email.setTargetObjectId(leadId); //having email raytest2@domain.com
email.setWhatId(customObject.Id);
emails.add(email);
List<Messaging.SendEmailResult> results = Messaging.sendEmail(emails);

I want the email to be sent to raytest1@domain.com (the email sent in the setToAddresses method), but not raytest2@domain.com (the email of the targetObject, which is Lead.Email).

Is this doable?

Answer 1

Now we can use setTreatTargetObjectAsRecipient(treatAsRecipient) and treatAsRecipient as false.

https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_classes_email_outbound_single.htm

Answer 2

Always templateId and targetObjectId walk hand in hand. If templateID is specified - email will always go to leadId

If you remove templateId- email will go to raytest1@domain.com

Answer 3

Setting setTreatTargetObjectAsRecipient to false does the trick,

BUT

It does not save as an activity on that target.