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AddressesByDomain

procedure AddressesByDomain(AList: TIdEMailAddressList;
  const ADomain: string);

Example​

procedure SelectDomain(const Source, Target: TIdEMailAddressList);
begin
  if (Target <> nil) and (Target <> Source) then
    Source.AddressesByDomain(Target, 'example.invalid');
end;

Usage​

AddressesByDomain clears a separate destination list and fills it with Text-round-tripped copies whose derived domains compare equal case-insensitively.

Additional Technical Info​

AddressesByDomain replaces a destination list with copies of source items whose derived Domain matches ADomain through Indy's TextIsSame, which calls Delphi AnsiCompareText in the current build.

ParameterMeaning
AListBorrowed destination list. It must be non-nil and must not be the source object.
ADomainComparison text. It is not trimmed, normalized or validated.

The first operation is AList.Clear. There is no nil guard, so nil fails immediately. More critically, passing the source as AList clears it before the loop obtains any entries; the method returns with the source empty. Always use a distinct destination.

Matching reads each item's Domain, which splits raw Address at the last at-sign. Addresses with no at-sign have empty domain and therefore match an empty ADomain.

AnsiCompareText is case-insensitive and locale-aware rather than an explicit invariant DNS comparison. The parameter is not lowercased. For deterministic domain policy, canonicalize valid domains independently before this call.

For each match the method adds a destination item and assigns its Text from the source's formatted Text. This parse/format round-trip does not preserve item identity and can normalize comments, spacing, quoting or malformed content. It differs from AddItems, which copies raw Address and Name fields.

The operation is non-transactional. Destination contents are destroyed before scanning. An exception can leave it empty or partially populated, and target owner callbacks can observe intermediate changes. Use a separately owned staging list and swap at a higher level when replacement must be atomic.

The scan is O(n) plus formatting/parsing allocation for each match. Source, destination and their owners are mutable and not thread-safe.

The source-reviewed example enforces both destination preconditions and uses a reserved domain. It did not execute SMTP or runtime mail code.

External references

Created 2026-07-15