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AddStrings

procedure AddStrings(Strings: TStrings);

Example​

procedure MergeNames(const Source, Target: TStringList);
begin
  Target.AddStrings(Source);
end;

Usage​

AddStrings adds every string and associated object reference from another TStrings object inside a balanced update batch.

  • Use a distinct source and target and decide explicitly who owns associated objects.
  • The call is not transactional. Update batching suppresses/coalesces notifications; it does not rollback.
  • Nil source, invalid source references, allocation errors, duplicate-policy errors and event-handler errors propagate.

Usage guidance​

  • Use a distinct source and target and decide explicitly who owns associated objects.
  • The call is not transactional. Update batching suppresses/coalesces notifications; it does not rollback.
  • Nil source, invalid source references, allocation errors, duplicate-policy errors and event-handler errors propagate.
  • Use Assign only when the API intentionally needs formatting/encoding settings copied as well; this method copies entry pairs only.

Additional Technical Info​

AddStrings is declared by hidden ancestor TStrings and is normally used through a concrete visible descendant such as TStringList. It copies entries rather than transferring them, and it does not copy formatting, encoding or comparison properties.

Source-backed behaviour​

The base overload calls BeginUpdate, loops from zero through the source count captured for the for bound, and calls AddObject for each source Strings[I] and Objects[I]. EndUpdate runs in finally.

TStringList overrides this path. An unsorted target inserts every pair directly at the end. It uses the same fast append path when the target is empty and both source and target are equally sorted TStringList instances with matching case, locale and duplicate settings; other sorted cases fall back to the base per-entry AddObject path. Object references remain shallow copies in every branch. Self-add duplicates the original bound's entries but sorting can change which source entry occupies a later index, so it is not a safe cloning operation. A failure partway through leaves already-added entries in place.

AddObject defines each pair insertion. BeginUpdate and EndUpdate define notification batching. Equals ignores object associations.

Official RTL references​

Created 2026-07-15