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First

procedure First;

Example​

procedure RewindData(const Data: TvxClientDataSet);
begin
  Data.First;
end;

Usage​

Moves to the first available record after resolving any pending edit through browse mode.

  • Explicitly Post/Cancel first when implicit browse-mode resolution is unacceptable.
  • On unidirectional datasets, First can reopen/re-execute the dataset and repeat external work.
  • Do not interpret BOF alone as empty; use IsEmpty or BOF and EOF together with Active context.

Additional Technical Info​

First is declared by hidden ancestor TDataSet and is normally used through a visible descendant such as TvxClientDataSet. Navigation has edit and event side effects; it is not a pure cursor assignment.

Source-backed behaviour​

The compiled base calls CheckBrowseMode, so a modified edit can be posted and an unmodified one cancelled. It runs before-scroll, handles unidirectional datasets by closing/reopening when not already at BOF, otherwise clears buffers, invokes descendant InternalFirst, fills forward buffers, sets BOF true, emits dataset-change and runs after-scroll.

For an empty dataset BOF and EOF can both be true. For TCustomClientDataSet, cursor/provider errors propagate through descendant record retrieval.

Last moves to the opposite boundary. MoveBy, Next and Prior navigate relatively.

Official RTL references​

Created 2026-07-15