Question

I am new to c# and use it with unity3D. When I use the new keyword to initialize an object it seems to have null in it even though the object is created and the constructor executes:

public class Wire
{
  public Wire()
  { 
    System.Console.WriteLine("constructor executed");
    System.Console.WriteLine(this);
  }
}

Wire wire1 =new Wire();
System.Console.WriteLine(wire1);

The output is:

constructor executed
null
null

I need to store the reference in a list but now I can’t. How can I solve this problem?

---

ok the actual code is

public class SharedResources
{    
    public static Dictionary< GameObject , Wire> dict = 
       new Dictionary<GameObject, Wire>();
    //...
}

public class Wire
{
    public GameObject x = y.y; 
    //y.y is another gameobject so its a normal copy constructer

    public Wire()
    { 
        print("constructor executed"); 
        // print is provided from unity package
        SharedResources.dict.Add( x,this);
    }
}

and in the main i have

Wire wire1 = new Wire();
if ( SharedResources.dict.ContainsKey( wire1.x) )
{
    print("ok"); // it does print that!!
    if ( SharedResources.dict[wire1.x] !=null )
        print("its not null");
    else
        print("its null");
}

output:

constructor executed
ok
its null

Answer 1

That is not possible.

The this keyword can never be a null reference, a constructor can never return a null reference, and calling Console.WriteLine with a null reference doesn’t display “null”, it displays an empty line, i.e the same as Console.WriteLine(String.Empty).

You can get that behaviour if you override the ToString method to return the string "null":

public class Wire {

  public Wire() {
    System.Console.WriteLine("constructor executed");
    System.Console.WriteLine(this);
  }

  public override string ToString() {
    return "null";
  }

}