private PeriodFormViewModel CreatePeriodForm(Period period, IObservable <bool> canDelete)
{
var periodForm = new PeriodFormViewModel(period, canDelete, this.ResourceManager);
periodForm.Delete
.WhereNotNull()
.Subscribe(_ => this.CurrentPosterIndex = 0);
periodForm.Delete
.WhereNotNull()
.Subscribe(deletedPeriod => this.periodsSource.Remove(deletedPeriod));
return(periodForm);
}
private bool ArePeriodsNonOverlapping(PeriodFormViewModel earlier, PeriodFormViewModel later) => Int32.TryParse(earlier.EndYear, out int earlierEndYear) && Int32.TryParse(later.StartYear, out int laterStartYear) && (earlierEndYear < laterStartYear || earlierEndYear == laterStartYear && earlier.EndMonth <= later.StartMonth);
