Dart

Count the Related Items in an Email

Demonstrates the read-only Chilkat Email.NumRelatedItems property, which is the number of related MIME items in the email. Related items are resources — such as images or style sheets — embedded with an HTML body in a multipart/related enclosure, and are commonly referenced by the HTML using a cid: URL or a Content-Location. Indexes are zero-based. This example sets an HTML body, adds a related item, and prints the count.

Background: When an HTML email shows an image that travels inside the message (rather than being downloaded from the web), the image is a "related item." The HTML references it with <img src="cid:logo.png">, and a matching part carries a Content-ID of logo.png. The whole bundle lives in a multipart/related enclosure. This is different from an attachment: related items are meant to be displayed as part of the body, not saved as separate files.

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Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the read-only Email.NumRelatedItems property.  Related items are
  // resources (such as images or style sheets) embedded alongside an HTML body in a
  // multipart/related enclosure, typically referenced from the HTML by a cid: URL.

  final email = CkEmail();

  // Set an HTML body that references a related item by content-id.
  email.setHtmlBody('<html><body><img src="cid:logo.png"/></body></html>');

  // Add the related item.  AddRelatedString returns the content-id assigned to it.
  // The empty charset argument means no charset conversion is applied.
  final cid = email.addRelatedString('logo.png', '(pretend this is image data)', '');
  print('Related content-id = $cid');

  print('NumRelatedItems = ${email.numRelatedItems}');
}