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Count

property Count: Integer read;

Example​

function HasCollectionItems(const Items: TCollection): Boolean;
begin
  Result := Items.Count > 0;
end;

Usage​

Count reports the live number of items currently owned by a collection.

Parameters and result

Read-only Integer. An empty collection returns 0.

Behaviour

  • The value changes immediately as items are added, inserted, removed or destroyed.
  • Count says nothing about an item's persistent ID, validity of its fields or business meaning.
  • A previously read value can become stale after callbacks or other code mutate the collection.
  • Use a fresh count when validating a later index.

Errors and edge cases

Reading through a nil collection raises an object-reference failure. The property itself has no overflow under normal list limits; allocation/list limits constrain practical size.

Additional Technical Info​

Count is a script-visible property declared on hidden ancestor TCollection. Visible descendant classes inherit it even though Classes/Common is intentionally omitted from the Velox and Docusaurus Code Library menus.

Count is the current number of item references in the collection's internal list. Valid positional indexes are zero through Count - 1.

Implementation trace

The PascalScript read helper calls Delphi TCollection.Count. Studio 37.0 returns the internal generic list's Count without scanning items.

Side effects and ownership

No side effect and no ownership transfer.

Performance and concurrency

O(1). Concurrent mutation makes the observation unstable and collection access is not synchronised.

Remarks

This entry describes the installed Delphi Studio 37.0 terminal reached by the Velox-modified PascalScript registration. Free Pascal is linked for compatible Object Pascal context; where implementations differ, the traced Delphi behaviour above is authoritative. The example is source-reviewed and non-destructive except where the named operation is inherently destructive.

Related entries

External references

Created 2026-07-15