Why DataTemplate executes code more than 1 time?

[criss02-cs]

I'm trying to develop a Calendar in .NET MAUI, and I'm using a CarouselView to display the list of months. Inside I use the ItemTemplate property to define the graphic interface for each month. I associate the ItemTemplate with code and when I try to open the page it takes a really long time to open, and I saw that the problem lies when I render the graphic interface of my DataTemplate, but in the meantime I saw that that code is executed 3/4 times.

This is MonthView, which I use on DataTemplate

using System.Diagnostics;
using System.Globalization;
using ObsidianUI.Components.Converters;
using ObsidianUI.Components.Interfaces;
using ObsidianUI.Components.Models;
using ObsidianUI.Components.Utils;
using static System.Runtime.InteropServices.JavaScript.JSType;

namespace ObsidianUI.Components.Controls;

[XamlCompilation(XamlCompilationOptions.Compile)]
internal class MonthView : ContentView
{
    private new CalendarView? Parent => base.Parent is CalendarView view ? view : null;
    private CultureInfo CurrentCulture => Parent is not null ? Parent.Culture : new CultureInfo("en-US");

    public static readonly BindableProperty MonthProperty =
        BindableProperty.Create(nameof(Month),
            typeof(Month),
            typeof(MonthView),
            null,
            BindingMode.Default,
            propertyChanged: MonthPropertyChanged);

    private bool isBusy = false;

    private static void MonthPropertyChanged(BindableObject bindable, object oldvalue, object newvalue)
    {
        if (bindable is not MonthView monthView) return;
        monthView.Update();
    }

    public Month? Month
    {
        get => (Month)GetValue(MonthProperty);
        set => SetValue(MonthProperty, value);
    }
    public MonthView()
    {
        //Update();
    }

    private void Update()
    {
        if (Month is null) return;
        var stopwatch = new Stopwatch();
        stopwatch.Start();
        var result = new MonthBuilder(Month, Month.Culture)
            .SetDefinitions()
            .PopulateData(Month.Days, Month.DayWeeks)
            .Build();
        Debug.WriteLine($"Before load user interface: {stopwatch.ElapsedMilliseconds}");
        Content = result;
        stopwatch.Stop();
        Debug.WriteLine($"Load user interface of date {Month.Date.Month}: {stopwatch.ElapsedMilliseconds}");
    }
}

And now che component where is the CarouselView

using System.Diagnostics;
using System.Globalization;
using Microsoft.Maui.Controls.Shapes;
using ObsidianUI.Components.Interfaces;
using ObsidianUI.Components.Models;

namespace ObsidianUI.Components.Controls;

public partial class CalendarView : ContentView
{
    private readonly int _weeksInAMonth = 5;
    private readonly int _daysInAWeek = 7;

    private List<ICalendar> _calendars = [];

    #region BindableProperties

    public readonly BindableProperty CultureProperty =
        BindableProperty.Create(nameof(Culture), typeof(CultureInfo), typeof(CalendarView), new CultureInfo("en-US"),
            propertyChanged: CulturePropertyChanged);
    public readonly BindableProperty ShownDateProperty =
        BindableProperty.Create(nameof(ShownDate), typeof(DateTime), typeof(CalendarView), DateTime.Today,
            propertyChanged: ShownDatePropertyChanged);

    public readonly BindableProperty OtherMonthDayTextColorProperty =
        BindableProperty.Create(nameof(OtherMonthDayTextColor), typeof(Color), typeof(CalendarView), Colors.Gray);

    //public readonly BindableProperty CalendarTypeProperty =
    //    BindableProperty.Create(nameof(CalendarType), typeof(CalendarType), typeof(CalendarView), CalendarType.DAY);

    #endregion

    #region Properties

    public DateTime ShownDate
    {
        get => (DateTime)GetValue(ShownDateProperty);
        set => SetValue(ShownDateProperty, value);
    }

    public CultureInfo Culture
    {
        get => (CultureInfo)GetValue(CultureProperty);
        set => SetValue(CultureProperty, value);
    }

    public Color OtherMonthDayTextColor
    {
        get => (Color)GetValue(OtherMonthDayTextColorProperty);
        set => SetValue(OtherMonthDayTextColorProperty, value);
    }

    //public CalendarType CalendarType
    //{
    //    get => (CalendarType)GetValue(CalendarTypeProperty);
    //    set => SetValue(CalendarTypeProperty, value);
    //}

    #endregion

    #region PropertiesChangedEvents

    private static void ShownDatePropertyChanged(BindableObject bindable, object oldvalue, object newvalue)
    {
        if (bindable is not CalendarView control) return;
        if (oldvalue is not DateTime old || newvalue is not DateTime newDate) return;
        if (old.Month == newDate.Month && old.Year == newDate.Year) return;
        control.Update();
    }
    private static void CulturePropertyChanged(BindableObject bindable, object oldvalue, object newvalue)
    {
        if (bindable is not CalendarView control) return;
        control.Update();
    }

    #endregion
    public CalendarView()
    {
        InitializeComponent();
        // Update();
        CarouselView.ItemsSource = _calendars;
        CarouselView.ItemTemplate = new DataTemplate(() =>
        {
            var monthView = new MonthView
            {
#if ANDROID || IOS
                WidthRequest = Width,
                HeightRequest = CarouselView.Height,
#else
                WidthRequest = Width - 20,
                HeightRequest = CarouselView.Height - 20,
#endif
                //Parent = this
            };
            monthView.SetBinding(MonthView.MonthProperty, new Binding("."));
            return monthView;
        });
    }

    private void Update()
    {
        var actual = new Month(ShownDate, Culture);
        _calendars.Clear();
        _calendars.AddRange([
            new Month(ShownDate.AddMonths(-1), Culture),
            actual,
            new Month(ShownDate.AddMonths(1), Culture),
        ]);
        //CarouselView.ItemsSource = _calendars;

        CarouselView.CurrentItem = actual;
    }

    private void CalendarView_OnSizeChanged(object? sender, EventArgs e)
    {
        //Update();
    }

    private void CarouselView_OnCurrentItemChanged(object? sender, CurrentItemChangedEventArgs e)
    {
        if (e.CurrentItem is not ICalendar currentDate) return;
        HeaderText.Text = currentDate.GetHeaderString();
    }

    private string GetMonthName(DateTime date)
    {
        var firstDayOfMonth = new DateTime(date.Year, date.Month, 1);
        var index = firstDayOfMonth.Month - 1;
        var monthName = Culture.DateTimeFormat.MonthNames[index];
        return $"{char.ToUpper(monthName[0])}{monthName[1..]}";
    }

    private void Button_OnPressed(object? sender, EventArgs e)
    {
        if (sender is not Button button) return;
        var index = _calendars.IndexOf((ICalendar)CarouselView.CurrentItem);
        if (button == PrevButton)
        {
            CarouselView.ScrollTo(index - 1);
        }
        else
        {
            CarouselView.ScrollTo(index + 1);
        }
    }
}

You can clearly see that the code is executed several times, does anyone know why? Or how can I solve it?