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dupError

dupError = 2

Example​

procedure RejectDuplicateNames(const Names: TStringList);
begin
  Names.Sorted := True;
  Names.Duplicates := dupError;
end;

Usage​

dupError rejects a comparator-equal insertion into a sorted TStringList by raising a duplicate-string exception before insertion.

Additional Technical Info​

dupError is ordinal 2 of TDuplicates. When a sorted TStringList finds an equal existing value, Add/AddObject raises the Delphi duplicate-string/list error before inserting the new pair.

Equality uses the active list comparator, including case and locale settings. A spelling that is distinct ordinally can therefore be rejected as equal. Configure comparison, Duplicates and Sorted before population so all entries follow one contract.

The failed insertion does not transfer/store the new associated object. If the caller created that object, the caller still owns it and must release it on the exception path. Earlier successful additions remain; bulk population is not transactional.

With Sorted=False, the duplicate policy is normally ignored. The example is source-reviewed only; no duplicate exception was raised.

External references

Created 2026-07-15