C# - Get number of references to object

Question

I\'m trying to write a simple Resource Manager for the little hobby game I\'m writing. One of the tasks that this resource manager needs to do is unloading unused resources.

Answer 1

It sounds to me that you could just use WeakReference from the resource manager. The GC will do the rest. You'll need to do a little casting, but it will be simple, and will work.

class Manager {
    Dictionary refs =
        new Dictionary();
    public object this[string key] {
        get {
            WeakReference wr;
            if (refs.TryGetValue(key, out wr)) {
                if(wr.IsAlive) return wr.Target;
                refs.Remove(key);
            }
            return null;
        }
        set {
            refs[key] = new WeakReference(value);
        }
    }
}
static void Main() {
    Manager mgr = new Manager();
    var obj = new byte[1024];
    mgr["abc"] = obj;

    GC.Collect(GC.MaxGeneration, GCCollectionMode.Forced);
    Console.WriteLine(mgr["abc"] != null); // true (still ref'd by "obj")

    obj = null;
    GC.Collect(GC.MaxGeneration, GCCollectionMode.Forced);
    Console.WriteLine(mgr["abc"] != null); // false (no remaining refs)
}