var red = new Label
        {
            Text = todoItem.Name,BackgroundColor = Color.Red,Font = Font.SystemFontOfSize (20)
        };

        red.SetBinding (Label.TextProperty,"Name");

        Button button = new Button
        {
            Text = String.Format("Tap for name change!")
        };

        button.Clicked += (sender,args) =>
        {
            _todoItem.Name = "Namie " + new Random().NextDouble();
        };

todoItem是下面类的对象.通知本身有效,我几乎是积极的.我想我的绑定有问题,或者我错过了这个概念.

public class TodoItem : INotifyPropertyChanged
{

    public event PropertyChangedEventHandler PropertyChanged;



    string _name;
    public string Name
    {
        get { return _name; }
        set
        {
            if (value.Equals(_name,StringComparison.Ordinal))
            {
                // Nothing to do - the value hasn't changed;
                return;
            }
            _name = value;
            OnPropertyChanged();
        }
    }

    void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        var handler = PropertyChanged;
        if (handler != null)
        {
            handler(this,new PropertyChangedEventArgs(propertyName));
        }
    }
}