How to refresh the Xamarin.Forms Calendar using MVVM pattern?

public class ViewModel : INotifyPropertyChanged
    {
        private ICommand _refresh;
 
        public ICommand Refresh
        {
            get
            {
                return _refresh;
            }
            set
            {
                _refresh = value;
                RaisePropertyChanged("Refresh");
            }
        }
 
        public ViewModel()
        {
            Refresh = new Command(ExecuteRefresh);
        }
 
        // Refresh Calendar from ViewModel
        private void ExecuteRefresh(object obj)
        {
            if (obj is SfCalendar)
            {
                (obj as SfCalendar).Refresh();
            }
        }
 
        public event PropertyChangedEventHandler PropertyChanged;
 
        private void RaisePropertyChanged(string name)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(name));
        }
    }

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:RefreshCalendar"
             xmlns:syncfusion="clr-namespace:Syncfusion.SfCalendar.XForms;assembly=Syncfusion.SfCalendar.XForms"
             x:Class="RefreshCalendar.CalendarView">
    <ContentPage.BindingContext>
        <local:ViewModel/>
    </ContentPage.BindingContext>
    <ContentPage.Content>
        <Grid>
            <Grid.RowDefinitions>
                <RowDefinition Height="*" />
                <RowDefinition Height="50" />
            </Grid.RowDefinitions>
            <syncfusion:SfCalendar x:Name="calendar" Grid.Row="0"/>
            <Button Grid.Row="1" Text="Refresh" Command="{Binding Refresh}" CommandParameter="{Binding Source={x:Reference calendar}}" WidthRequest="100" HeightRequest="30" />
        </Grid>
    </ContentPage.Content>
</ContentPage>