PureBasic

Get the Number of Body Alternatives in an Email

Demonstrates the read-only Chilkat Email.NumAlternatives property, which is the number of body representations present in the email. A representation may be plain text, HTML, iCalendar, or another body format. A normal email with one body returns 1, while a multipart/alternative email returns the number of alternatives it contains. Alternative indexes used by methods such as GetAlternativeBody are zero-based. This example builds an email with plain-text and HTML alternatives and prints the count.

Background: MIME organizes a message as a tree of parts. multipart/alternative holds several versions of the same content (the client shows the best one it supports); multipart/mixed combines a body with attachments; and multipart/related bundles an HTML body with the inline images it references. A rich email nests these, for example:

multipart/mixed
  multipart/alternative
    text/plain
    multipart/related
      text/html
      image/png
  application/pdf

Here the text/plain part and the multipart/related part are the two alternatives.

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IncludeFile "CkEmail.pb"

Procedure ChilkatExample()

    ;  Demonstrates the read-only Email.NumAlternatives property, which is the
    ;  number of body representations (plain text, HTML, iCalendar, etc.) in the email.

    email.i = CkEmail::ckCreate()
    If email.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ;  Set a plain-text body and add an HTML alternative.  This creates a
    ;  multipart/alternative email with two representations.
    CkEmail::ckSetTextBody(email,"This is the plain-text alternative.","text/plain")
    CkEmail::ckAddHtmlAlternativeBody(email,"<html><body><b>This is the HTML alternative.</b></body></html>")

    ;  Alternative indexes (used by GetAlternativeBody) are zero-based.
    Debug "NumAlternatives = " + Str(CkEmail::ckNumAlternatives(email))


    CkEmail::ckDispose(email)


    ProcedureReturn
EndProcedure