void OnRowClicked(object o, RowActivatedArgs args) { TreeIter Iter; if ((o as TreeView).Selection.GetSelected(out Iter)) { bool OldValue = (bool)MusicListStore.GetValue(Iter, 0); MusicListStore.SetValue(Iter, 0, !OldValue); Log.DebugFormat("Setting Selection Value For Row {0} -> {1}", MusicListStore.GetStringFromIter(Iter), !OldValue); } }