Dart

Add a Related Item from a BinData Object

Demonstrates the Chilkat Email.AddRelatedBd method, which adds a related item (such as an inline image) using the contents of a BinData object, and returns the generated Content-ID. This example loads an image into a BinData, adds it, captures the Content-ID, and references it from the HTML body.

Background: This is the binary, Content-ID-based way to embed an inline resource — the right choice for images, whose bytes belong in a BinData rather than a string. Because Chilkat generates the Content-ID, the usual pattern is: add the item first, capture the returned ID, then build the matching <img src="cid:..."> reference from it (done here with a StringBuilder).

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Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the AddRelatedBd method, which adds a related item (such as an inline image)
  // using the contents of a BinData object, and returns the generated Content-ID.

  final email = CkEmail();
  email.subject = 'Related image from BinData';

  // Load the image data from a file into a BinData object.
  final bdImage = CkBinData();
  try {
    bdImage.loadFile('qa_data/images/logo.png');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Add the image as a related item; capture its generated Content-ID.
  final String cid;
  try {
    cid = email.addRelatedBd('logo.png', bdImage);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Reference the related item in the HTML body by its Content-ID.
  final sbHtml = CkStringBuilder();
  sbHtml.append('<html><body><img src="cid:PLACEHOLDER_CID"/></body></html>');
  final numReplaced = sbHtml.replace('PLACEHOLDER_CID', cid);
  email.setHtmlBody(sbHtml.getAsString());

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

  // Note: The path "qa_data/images/logo.png" is a relative local filesystem path,
  // relative to the current working directory of the running application.
}