Dart

Attach a File with an Explicit Content Type

Demonstrates the Chilkat Email.AddFileAttachment2 method, which attaches a file from the filesystem and lets you explicitly specify its content type rather than having Chilkat infer it from the file extension. This example attaches a binary file as application/octet-stream.

Background: Extension-based type detection is convenient but not always right — a file may have an unusual or missing extension, or you may need a very specific MIME type for the recipient to process it correctly. Specifying the content type explicitly removes the guesswork. application/octet-stream is the generic "arbitrary binary data" type, a safe default that tells the client to treat the attachment as an opaque download rather than trying to render it.

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Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the AddFileAttachment2 method, which attaches a file and lets you
  // explicitly specify its content type instead of letting Chilkat infer it.

  final email = CkEmail();
  email.subject = 'Email with a file attachment';
  email.body = 'Please see the attached file.';

  // Attach a file, explicitly specifying the content type.
  try {
    email.addFileAttachment2('qa_data/attachments/data.bin', 'application/octet-stream');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('NumAttachments = ${email.numAttachments}');

  // Note: The path "qa_data/attachments/data.bin" is a relative local filesystem path,
  // relative to the current working directory of the running application.
}