Skip to main content

AsDateTime

property AsDateTime: TDateTime read write;

Example​

procedure ScriptEvent(var Value: variant);
var
  Text: TJSONString;
  Item: TJSONValue;
begin
  Text := TJSONString.Create;
  try
    Item := Text;
    Item.AsString := '2026-07-20T03:30:00.000Z';
    Value := Item.AsDateTime;
  finally
    Text.Free;
  end;
end;

Usage​

AsDateTime converts ISO 8601 text to a UTC TDateTime and writes an input already treated as UTC with a Z designator.

Additional Technical Info​

The reader returns 0 (NULLDATE) when IsNull is true. Otherwise it calls Delphi ISO8601ToDate(AsString, True). The True argument requests a UTC result: an explicit source offset is applied and a Z timestamp remains UTC. Invalid or unsupported text raises EConvertError; the property does not fall back or pre-check ValueType.

The writer calls DateToISO8601(aValue, True) and assigns the result through AsString. The True argument means the supplied numeric TDateTime is already UTC. It does not convert a local value to UTC before appending the Z designator. Convert local time explicitly before assignment or the timestamp will be mislabeled.

Zero is not treated specially by this property: writing 0 produces the ISO representation of Delphi's zero date rather than semantic JSON null. By contrast, some AddDateTime helpers use exact zero as a null sentinel. Read null state separately when that distinction matters.

The concrete receiver controls storage. A String node stores ISO text; a compatible date-like String convention round-trips. A Boolean/number may reject the generated text after changing null state, and a container attempts to parse/replace itself. The conversion is synchronous. Parsing/formatting allocates text and depends on Delphi's date utilities, but the explicit UTC flags avoid local-time-zone lookup on this selected path.

External references

Created 2026-07-15