AttachmentCount property

AttachmentCount enumerates embedded file streams reachable through the catalogue /Names /EmbeddedFiles name tree (PDF 1.7 spec section 7.11). These are arbitrary files (XML, spreadsheets, source CAD, signed XML, ZIP archives,…) packaged inside the PDF and exposed by viewers as the “Attachments” sidebar. PDF/A-3 specifically requires every relevant source artefact to be embedded this way for long-term reproducibility

The value is 0 when Active is False and when the document carries no embedded files. File-attachment annotations (subtype /FileAttachment) are not counted here — those are page-level annotations and surface through AnnotationCount instead. PDFium Delphi Component exposes embedded streams as TBytes via Attachment[Index]; the human-readable file name and MIME-style type are available through AttachmentName[Index] and AttachmentType[Index]

The typical loop is for I := 0 to Pdf.AttachmentCount - 1 do. Each Attachment[I] access decompresses the embedded file stream into memory, so cache the TBytes if you need to write it to disk and pass it to a parser. Adding or removing an attachment invalidates indices — re-read AttachmentCount after a mutation

Only the /EmbeddedFiles name tree is enumerated. A PDF 2.0 associated file (ISO 32000-2 §7.11.4) referenced solely from an /AF array — on the catalogue, a page, an annotation or any other object — and not also registered in the name tree is neither counted nor given an index for Attachment, AttachmentName or AttachmentRelationship. This includes files written by SaveAsWithAssociateFiles, which adds /AF entries only. Most PDF/A-3 producers, including Factur-X and ZUGFeRD tools, register each associated file in both places, so those files are listed normally

• Useful for archival workflows: PDF/A-3 viewers commonly surface attachments as the canonical source data for the visible PDF report
• Security note: attachments can be arbitrary executable formats. Treat their content as untrusted input when you extract them
• Combine with FeatureSupported(feAttachment) to detect whether the installed PDFium build supports modifying attachment names