Question

I have a very simple class that wont compile because of a default parameter in the constructor. The language is C# and the class will be used in a Unity3d game. So this compile error is occurring in Unity’s “IDE”

Compile Error:

Assets/Utilities/GenericClasses.cs(30,94): error CS1736: The expression being assigned to optional parameter `nName’ must be a constant or default value

public class Element {
    public static readonly string NULL_NAME = "___NULL_NAME___";
    public enum elementType {E_ELEMENT, E_MODEL, E_VIEW, E_SUPER, E_ARC};
    private string name;
    private elementType type;

    // line 30 is below
    public Element(elementType nType=elementType.E_ELEMENT, string nName=NULL_NAME) {
        type = nType;
        name = nName;
    }
}

What am I doing wrong?

Answer 1

You should use a constant value instead of a static readonly:

public const string NULL_NAME = "___NULL_NAME___";

The reason why your code doesn’t compile is because you attempted to assign a non constant default value to the nName parameter in the constructor which is not supported.