LoadData.cs

public partial class MainPage : ContentPage
{
    private MainPageViewModel ViewModel => BindingContext as MainPageViewModel;


    public MainPage(MainPageViewModel viewModel)
    {
        InitializeComponent();

        BindingContext = viewModel;
    }

    protected override void OnBindingContextChanged()
    {
        base.OnBindingContextChanged();

        MainThread.BeginInvokeOnMainThread(async () => await ViewModel.LoadData());
    }

}