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Components

property Components[Index: Integer]: TComponent read;

Example​

function FirstOwnedComponent(const Container: TComponent): TComponent;
begin
  Result := nil;
  if Container.ComponentCount > 0 then
    Result := Container.Components[0];
end;

Usage​

Components returns a live component reference from an owner's zero-based immediate component list.

Parameters and result

Index is zero-based from 0 through ComponentCount - 1. The result is a live TComponent reference.

Behaviour

  • The list is ownership, not necessarily visual parent/child structure.
  • Index order can change through ComponentIndex or other Velox ownership operations.
  • Destroying/removing a child invalidates returned aliases.
  • Check a fresh ComponentCount immediately before ordinary indexed iteration.

Errors and edge cases

Nil receiver, absent list or invalid index raises; this property does not return nil for an out-of-range request.

Additional Technical Info​

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

Components provides positional access to immediately owned components. The returned child remains owner-managed; reading it does not copy or retain the object.

Implementation trace

The PascalScript indexed-property helper calls Delphi's Components[Index] getter. Studio 37.0 raises a list-index error when no list exists or the index is outside the current bounds, otherwise it returns the stored pointer.

Side effects and ownership

Read-only and no ownership transfer. Mutating or freeing the returned component affects the owner graph and requires the concrete API's lifetime rules.

Performance and concurrency

O(1) after bounds checking. The live reference is unsafe across concurrent mutation or destruction.

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