PACKED_POSITION_TYPE_CHILD & PACKED_POSITION_TYPE_Group doesn't exist in Expandable ListView

How to get above constants? OnContextItemSelected function i want to get the the id of clicked row in Expandable ListView. Using below code

public override bool OnContextItemSelected (IMenuItem item)
        {
                     int type = ExpandableListView.GetPackedPositionType(info.PackedPosition);
                if (type == ExpandableListView.PACKED_POSITION_TYPE_CHILD) {
                    groupPos = ExpandableListView.GetPackedPositionGroup(info.PackedPosition); 
                    childPos = ExpandableListView.GetPackedPositionChild(info.PackedPosition); 

                    return true;
                } else if (type == ExpandableListView.PACKED_POSITION_TYPE_GROUP) {
                    childPos = ExpandableListView.GetPackedPositionChild(info.PackedPosition); 
                    groupPos = ExpandableListView.GetPackedPositionGroup(info.PackedPosition); 

                    return true;
                }
         }

Getting error as Android.Widget.ExpandableListView doesn't contain a definition for PACKED_POSITION_TYPE_CHILD & PACKED_POSITION_TYPE_GROUP