更改ViewModel xamarin forms android中的数据绑定值

public class MyViewModel : INotifyPropertyChanged
{
    private string _myProperty;
    
    public string MyProperty
    {
        get { return _myProperty; }
        set
        {
            if (_myProperty != value)
            {
                _myProperty = value;
                OnPropertyChanged(nameof(MyProperty));
            }
        }
    }
    
    public event PropertyChangedEventHandler PropertyChanged;
    
    protected virtual void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

public partial class MyPage : ContentPage
{
    private MyViewModel _viewModel;
    
    public MyPage()
    {
        InitializeComponent();
        
        _viewModel = new MyViewModel();
        BindingContext = _viewModel;
    }
}

private void Button_Clicked(object sender, EventArgs e)
{
    var viewModel = (MyViewModel)BindingContext;
    viewModel.MyProperty = "New Value";
}