public ProblemViewModel()
{
_repoClasses = new RepositoryClasses();
_problemsObs = _repoClasses.ProblemObs;
_problemsObs.CollectionChanged += _problemsObs_CollectionChanged;
_problemExecuteObs = _repoClasses.ProblemExecuteObs;
_problemExecuteObs.CollectionChanged += _problemExecuteObs_CollectionChanged;
_settClass = _repoClasses.SettClass;
_synthesizer = _repoClasses.Synthesizer;
//
_timeSumObs = new TimeSummaryObservable(TimePeriodType._day, DateTime.Now);
_timeSumObs.AddTimeSummary(_problemsObs, TimePeriodType._day);
//
_dateForIndicator = DateTime.Now;
NearestProblem = NearestProblemSet(_problemsObs[0]);
}