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SortByDomain

procedure SortByDomain;

Example​

procedure OrderByDomain(const Addresses: TIdEMailAddressList);
begin
  // Do not retain item references as recipient identities across this call.
  Addresses.SortByDomain;
end;

Usage​

SortByDomain stably bubble-sorts by case-sensitive locale domain order by swapping and reparsing Text content between fixed item objects.

Additional Technical Info​

SortByDomain runs a full bubble-sort schedule over adjacent entries. It compares derived domain Strings through Indy's IndyCompareStr, which calls Delphi AnsiCompareStr in this build.

The comparison is case-sensitive and locale-aware. It does not lowercase or canonicalize domains first. Consequently Example.invalid and example.invalid can sort separately, and ordering can depend on the process/operating-system locale. Equal comparisons are not swapped, so the algorithm is stable relative to its comparator.

Critical identity behavior​

The method does not move collection objects. For an out-of-order pair it saves Items[j].Text, assigns the right item's Text into the left item, then assigns the saved Text into the right item.

Item object references, collection IDs and indexes therefore stay fixed while their recipient content changes. A variable that referred to "Alice" before sorting can refer to "Bob" afterwards. Do not retain TIdEMailAddressItem references as recipient identities across this operation; reacquire items and inspect them after sorting.

Swapping through Text formats and reparses each pair. This can normalize quotes, spaces, comments and malformed content, and it inherits the formatter/parser defects. It is not a byte-preserving swap of raw fields. If a setter or allocation raises between the two assignments, a pair can temporarily duplicate one value and lose the other; there is no rollback.

The implementation performs Count outer passes and Count - 1 adjacent comparisons per pass regardless of whether the list becomes sorted early. Time is O(n²), plus repeated formatting/parsing and managed-string allocation. This is unsuitable for very large recipient collections.

No collection item is added or deleted. The Text/raw-field setters do not call inherited Changed, so this complete recipient-content reorder does not issue a normal collection item-change notification. Owner/UI state that relies on such notifications can remain stale. The list and retained item references are mutable and not thread-safe.

The source-reviewed example explicitly warns about identity. It was not executed by the documentation workflow.

External references

Created 2026-07-15