private void SetButtonVisibility() { var selectedNode = (IdendtityNode)CurriculumnTreeView.SelectedNode; if (selectedNode != null) { if (selectedNode.Type == NodeType.Curriculum || selectedNode.Type == NodeType.Stage) { OpenTestButton.Enabled = false; } else { OpenTestButton.Enabled = ConditionChecker.IsViewingAllowed(((IdendtityNode)selectedNode.Parent).ID); } } }