public void CloneItem()
 {
     Thing clonedThing = new Thing();
     clonedThing.Name = SelectedThing.Name + " - copy";
     clonedThing.Price = SelectedThing.Price;
     Things.Add(clonedThing);
     SelectedThing = clonedThing;
 }
        public void DeleteItem()
        {
            Thing tempThing = new Thing();
            tempThing = SelectedThing;
            if (Things.IndexOf(SelectedThing) != 0)
            {
                SelectedThing = Things.FirstOrDefault();
            }
            else if (Things.Count==1)
            {
                SelectedThing = null;
            }
            else
            {
                SelectedThing = Things[1];
            }

            Things.Remove(tempThing);
        }
 public void AddItem()
 {
     Thing newThing = new Thing();
     Things.Add(newThing);
     SelectedThing = newThing;
 }