Question

I’m working on bettering my strategy of working with classes and objects.

What is the best way of passing an object down a through a chain of specific classes to keep the code organized.

example: working with a ZedGraph object (note) this may not be the best example but it will get the idea across.

class Graphhandler
{
    private ZedGraphControl ZGC;
    private SubGraphController PortionofGraph;

    public class GraphHandler(ZedGraphControl _ZGC)
    {
         ZGC = _ZGC;
         initializeGraph();
    }

    private void initializeGraph()
    {
        // notice I am putting the ZGC Object into another class
        // and likely that ZGC object will go into another class
        PortionofGraph = new SubGraphController(ZGC);
    }        
}    

class SubGraphController
{
    private ZedGraphControl ZGC;
    private DeeperSubGraphController PortionofGraph;

    public class SubGraphController(ZedGraphControl _ZGC)
    {
         ZGC = _ZGC;
         initializeSubGraph();
    }

    private void initializeSubGraph()
    {
        PortionofGraph = new DeeperSubGraphController(ZGC); 
        // is there a better way?
    }

}

Is there a better way of passing a yop level object down through all these calls to manipulate the data?

Answer 1

Normally, the answer is to pass fully-formed dependencies into your objects. For example:

public GraphHandler(SubGraphController portionOfGraph) {
     this.portionOfGraph = portionOfGraph;
}

public SubGraphController(DeeperSubGraphController portionOfGraph) {
     this.portionOfGraph = portionOfGraph;
}


...

var zedGraphControl = new ZedGraphControl();
var deeperSubGraphController = new DeeperSubGraphController(zedGraphControl);
var subGraphController = new SubGraphController(deeperSubGraphController);
var graphHandler = new GraphHandler(subGraphController);

Rather than constructing the DeeperSubGraphController directly in you subgraph controller. Nowadays, you usually orchestrate all this using a dependency injection framework.

(See also: Dependency Injection Myth: Reference Passing)