#733 – How to Tell If an Object Has Been Garbage Collected

You normally can’t tell whether an object has been garbage collected by using some reference to the object–because once you have a reference to the object, it won’t be garbage collected.

You can instead create a weak reference to an object using the WeakReference object.  The weak reference is one that won’t be counted as a reference, for purposes of garbage collection.

In the code below, we check before and after garbage collection to show that a Dog object is garbage collected.

            Dog dog = new Dog("Bowser");

            WeakReference dogRef = new WeakReference(dog);
            Console.WriteLine(dogRef.IsAlive);

            dog = null;
            GC.Collect();

            Console.WriteLine(dogRef.IsAlive);