C# WeakReference object is NULL in finalizer although still strongly referenced

Question

Hi I have code here where I don\'t understand why I hit the breakpoint (see comment).

Is this a Microsoft bug of something I don\'t know or I don\'t understand prope

Answer 1

The WeakReference _weakB is available for garbage collection at the same time as the object a is. You don't have a guarantee of order here, so it could very well be that _weakB is finalized before object a.

Accessing _weakB in the finalizer of A is dangerous, since you don't know the state of _weakB. I'm guessing that in your case it has been finalized, and that that is causing it to return null for .Target.