Listening to PropertyChanged from another class

Question

How can I listen in class B to the PropertyChanged events from class A? I would like to listen to changes of a property from class A.

class A : INotifyPropertyChanged
{
        private int _x;

        public int X
        {
            get => _x;
            set
            {
                if (_x == value) return;
                _x = value;
                OnPropertyChanged(nameof(X));
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void OnPropertyChanged(string propertyName)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
}

class B
{
        public B(int x)
        {
            // In this class I want to listen to changes of the property X from class A
        }
}

user_11080161 · Answer

Just listen to the event:

class B
{
    public A _myA;

    public B(int x)
    {
        _myA = new A();
        _myA.PropertyChanged += A_PropertyChanged;
    }

    private void A_PropertyChanged(object sender, PropertyChangedEventArgs e)
    {
        if (e.PropertyName != nameof(_myA.X)) return;
    }
}

Listening to PropertyChanged from another class

1 Answers