Question PropertyDrawer for Array Item Add Event.

I made a custom property drawer for array. OnGUI function is called for each item in array. How can I write a PropertyDrawer to get item added/removed events?

Code (CSharp):

1.  
2. [OnCollectionChanged("OnTestListChanged")]
3. public string[] TestList;
4.  
5. [CustomPropertyDrawer(typeof(OnCollectionChangedAttribute))]
6. public class OnCollectionChangedDrawer : PropertyDrawer
7. {
8.  public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
9. {
10. }
11. }
12.