XtraTreeList is maintained and developed by DevXpress. A suite of components programmed in the c# language. Products can be ordered with or without full source code. Mono is not explicitly supported.
A developer license costs 299 US$ including the source code.
The XtraPivotGrid component by the same vendor has been used successfully in the Verkenner project. Cluttered with features, visually very attractive. Analysis with Moma indicated some compatibility problems with mono, but the list was not very extensive.
Current Treeview implementation was realized by customizing a treeview by G. Donchyts. That he developed in the Ukraine. It still lacks the ability to edit labels of treenodes.
Some other examples
VB.Net example of database linked treeview
C# example of database linked treeview
treeview required functionality
dragdrop
edit labels
update labels
update icons
expand, collapse
mouse interaction
menus
xml
keyed list with icons to used based on object type of treenode ??
