How to have a WPF binding update every second?

Question

I want to show the user how many seconds have passed since some event occurs. Conceptually, my view model has properties like this:

public DateTime Occurred         


        

Answer 1

You could create a single DispatcherTimer statically for your view model, and then have all instances of that view model listen to the Tick event.

public class YourViewModel
{
    private static readonly DispatcherTimer _timer;

    static YourViewModel()
    {
        //create and configure timer here to tick every second
    }

    public YourViewModel()
    {
        _timer.Tick += (s, e) => OnPropertyChanged("SecondsSinceOccurence");
    }
}