public DiagramLayerConsistencyState ConsistencyState {get;}

{
  // Get the NetworkDiagram from a DiagramLayer and check its ConsistencyState
  static void GetDiagram(DiagramLayer diagramLayer)
  {
    NetworkDiagram diagram = diagramLayer.GetNetworkDiagram();

    // Get the consistency state from the layer
    DiagramLayerConsistencyState diagramLayerConsistencyState = diagramLayer.ConsistencyState;

    // Or from the diagram
    NetworkDiagramConsistencyState diagramConsistencyState = diagram.GetConsistencyState();
  }
}