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NewValue

property NewValue: Variant read write;

Example​

function PendingStatus(const Data: TvxClientDataSet): Variant;
begin
  Result := Data.FieldByName('Status').NewValue;
end;

Usage​

NewValue reads or writes the client dataset's pending change-buffer value for an ordinary data field, distinguishing unchanged from explicit Null.

  • Use only in code that explicitly understands client-dataset delta/reconciliation semantics.
  • Distinguish Unassigned (not changed/not available) from Null (changed to database null).
  • Use ordinary Value for normal map processing of the active pending record.

Additional Technical Info​

NewValue addresses dataset state dsNewValue, used by client datasets to represent a pending/delta value rather than the ordinary active-record view.

Source-backed behaviour​

Reading calls GetStateFieldValue(dsNewValue, Field). TCustomClientDataSet selects its new-value buffer (or temporarily uses the active buffer), asks DSBase for the blank status, returns Unassigned for BLANK_NOTCHANGED, Null for BLANK_NULL, and otherwise converts the value through the concrete field. Non-stored field kinds return Null.

Writing calls SetStateFieldValue. It does nothing unless FieldKind = fkData; for a data field it temporarily switches dataset state to dsNewValue, assigns through AsVariant, then restores the old state. Client SetFieldData suppresses the normal field-change event in dsNewValue, but conversion/provider errors still propagate. This is low-level change-log behaviour and does not itself apply an update to a database.

Official RTL references​

Created 2026-07-15