Free or open source Tree-grid for C#?
ObjectListView is great:
(source: sourceforge.net)
This one isn't bad : http://www.codeproject.com/KB/tree/TreeWithColumns.aspx
The best one I used is DevExpress's XtraTreeList, but it's not free...
This one seems to work as well: http://www.codeproject.com/KB/list/treelistview.aspx