public sealed class TimeEvent
{
  public long Elapsed {get; private set;}
  public string Description { get; private set;}
  public TimeEvent(long elapsedTime, string descriptionOfEvent)
  {
    this.Elapsed = elapsedTime;
    this.Description = descriptionOfEvent;
  }
}

public abstract class BaseGridViewModel
{

    protected BaseGridViewModel()
    {
        Times = new List<TimeEvent>();
    }
    public IList<TimeEvent> Times {get; set;}

}

var sw = Stopwatch.StartNew();
vm.Times.Add(new TimeEvent(sw.ElapsedMillisends, "After event 1"));
sw.Stop();

vm.Event(sw, "After event 1"));

public abstract class BaseGridViewModel
{

    protected BaseGridViewModel()
    {
        Times = new List<TimeEvent>();
    }
    public IList<TimeEvent> Times {get; set;}

    public void Event(StopWatch watch, string message)
    {
        Times.Add(new TimeEvent(watch.ElapsedMilliseconds, message));
    }

}