Dart

Access a Part in a Multipart MIME Entity

Demonstrates the Chilkat Mime.PartAt method, which provides live access to the direct child at a zero-based index. The first argument is the index and the second is a Mime object that will reference the child. Modifying it modifies the child stored in the parent tree.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: This is how you reach into a multipart message to inspect or edit an individual part — read a part's Content-Type, extract an attachment's body, or change a part in place. The key point is that the returned Mime is a live reference, not a copy, so edits to it flow back into the parent tree. Loop from 0 to NumParts - 1 to visit every direct child.

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Dart

import 'package:chilkat/chilkat.dart';

void main() {
  final mime = CkMime();
  try {
    mime.loadMimeFile('qa_data/multipart_message.eml');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // PartAt provides LIVE access to a direct child part.  The 1st argument is the zero-based index
  // and the 2nd is a Mime object that will reference the child.  Modifying it modifies the child in
  // the parent tree.
  final n = mime.numParts;
  print('Number of parts: $n');

  final partVar = CkMime();
  for (var i = 0; i < n; i++) {
    try {
      mime.partAt(i, partVar);
    } on ChilkatException catch (e) {
      print(e.lastErrorText);
      return;
    }

    print('Part $i Content-Type: ${partVar.contentType}');
  }
}