bool IList.Contains(object value)
 {
     return(HierarchyView.FindDataIndex(value) != -1);
 }
 int IList.IndexOf(object value)
 {
     return(HierarchyView.FindDataIndex(value));
 }
 bool ICollection <object> .Contains(object item)
 {
     return(HierarchyView.FindDataIndex(item) != -1);
 }