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mptText

mptText = 0

Example​

procedure InspectTextPart(Part: TIdMessagePart; var IsPlainText: Boolean);
begin
  IsPlainText :=
    (Part.PartType = mptText) and
    (Part.ContentType = 'text/plain');
end;

Usage​

mptText classifies a Velox message part as a TIdText runtime object for text counting and script body handling.

Additional Technical Info​

mptText is returned by TIdText.PartType. It identifies the concrete text-part class and allows code to use TIdText.Body after an appropriate cast. It is not inferred from MIME Content-Type.

The example checks the runtime classification before applying a separate media-type rule. It is source-reviewed and is not executed by the documentation workflow.

Class versus headers

  • A TIdText still returns mptText if its ContentType is blank or misleading.
  • An attachment labelled text/plain still returns mptAttachment.
  • Content-ID/related membership is independent; a text part with Content-ID contributes to both cached TextPartCount and RelatedPartCount.
  • Custom descendants must override PartType to join the text classification; the base default is Attachment.

This distinction matters for safe casts and for message layout. Check PartType before treating a part as TIdText, then inspect ContentType/CharSet/ContentTransfer to decide how to interpret its body.

Counting and Velox behavior

TIdMessageParts.CountParts increments its cached TextPartCount for each current item returning this value. The count is a snapshot from the last scan rather than a live collection invariant.

Velox POP/IMAP automatic attachment download ignores mptText parts. Generated custom-script guidance handles them separately and distinguishes text/plain from text/html. Text bodies needed by a flow must therefore be handled in script or message-level processing rather than expected as downloaded attachment files.

Side effects, errors and performance

PartType is constant-time and side-effect free. Body interpretation or conversion can still fail because of malformed transfer data or charset metadata. Keep the owner alive and do not mutate the collection concurrently during iteration.

Related entries

External references

Created 2026-07-15