Unity has overloaded the ‘==’ operator, specifically, checking objects against “null” might not always do what you expect. More information can be found in this blog post from Unity.
Specifically, if a Unity Object (as opposed to a C# object) gets destroyed, it will be set to a “fake null” object. In this case, the following statements are true:
1 2 3 4 | obj == null // true obj is null // false (object)obj == null // false obj ?? value // obj |
Note the different results between lines 1 and 2 & 3.
If obj truly is null, then the results are as expected:
1 2 3 4 | obj == null // true obj is null // true (object)obj == null // true obj ?? value // value |
It may be more readable to provide an Extension Method to UnityObject:
/// <summary> /// Extension Method on Unity Objects returning whether the object really is null. /// </summary> /// Unity overloads the '==' operator so that it returns true on both null references /// as well as references to destroyed objects. This function only returns true if /// the reference truly is null, and returns false for "fake null" objects. public static bool IsTrueNull(this UnityEngine.Object ob) { return (object)ob == null; } |
