<pre>Selected date: @Date?.ToLongDateString()</pre>

<CalendarMonth @bind-Date="@Date" />

@code {
  private DateOnly? Date { get; set; } = new DateOnly(2021, 08, 20);

  private void OnMonthChange(DateOnly newDate)
  {
    Console.WriteLine($"updated month: {newDate.Month}, updated year: {newDate.Year}");
  }
}