Columns object
The ExTree control supports multiple columns. The Columns object contains a collection of Column objects. Use the Columns property of the control to access the control columns. By default, the control's columns collection is empty

  AddAdds a Column object to the collection and returns a reference to the newly created object. 
  ClearRemoves all objects in a collection. 
  CountReturns the number of objects in a collection. 
  ItemReturns a specific Column of the Columns collection. 
  ItemBySortPositionReturns a Column object giving its sorting position. 
  RemoveRemoves a specific member from the Columns collection.