program Test1;

{$APPTYPE CONSOLE}

{$R *.res}

uses
  System.SysUtils, System.JSON, Rest.Json;

type
  TTest = class(TObject)
    FDate: TDateTime;
    FName: string;
  public

  end;

  TJSonHelper = class helper for TJson
  public
    class procedure JsonStrToObject(AObject:TObject; AStr: string; AOptions: TJsonOptions = [joDateIsUTC, joDateFormatISO8601]);
  end;

var
  v: TTest;
  s: string;

{ TJSonHelper }

class procedure TJSonHelper.JsonStrToObject(AObject: TObject; AStr: string; AOptions: TJsonOptions);
var
  o: TJSONAncestor;
begin
  o := TJSONObject.ParseJSONValue(AStr);
  try
    Self.JsonToObject(AObject, o as TJSONObject, AOptions);
  finally
    o.Free;
  end;
end;

begin
  try
    v := TTest.Create();
    try
      s := '{"date":"2019-03-15T18:00:15.896","name":"Test"}';
      TJson.JsonStrToObject(v, s);
      s := TJson.ObjectToJsonString(v);
      Writeln(v.FName, ' = ', DateToStr(v.FDate));
      Writeln(s);
    finally
      v.Free;
    end;
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
end.