ViewModelBaseSample.cs

public class MyViewModel : ViewModelBase
{
      public event EventHandler DataUpdated

    public override Task Initialize()
    {
        //Subscribe to event when ViewModel in initialized.
        DataUpdated += Data_DataUpdated;
    }

    public override Task OnApplicationSleep()
    {
        //Unsubscribe to event.
        DataUpdated -= Data_DataUpdated;
    }
    
    public override Task OnApplicationResume()
    {
        //Subcribe to event again.
        DataUpdated += Data_DataUpdated;
    }
    
    private void Data_Updated(object sender, EventArgs e)
    {
        
    }
}