using System.ComponentModel; namespace ShowSeconds.ViewModel { public class SecondsDataContext : INotifyPropertyChanged { private string seconds; public string Seconds { set { seconds = value; OnPropertyChanged("Seconds"); } get { return seconds; } } public event PropertyChangedEventHandler PropertyChanged; private void OnPropertyChanged(string propertyName) { PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName)); } } }