Find references to the object in runtime

Question

I have an object, which lives forever. I am deleteing all references I can see, to it after using it, but it still not collected. Its life cycle is pretty sophisticated so I can't be sure that all references been cleared.

if ( container.Controls.Count > 0 ) {      var controls = new Control[ container.Controls.Count ];     container.Controls.CopyTo( controls, 0 );      foreach ( var control in controls )      {           container.Controls.Remove( control );          control.Dispose();     }      controls = null;  }  GC.Collect(); GC.Collect(1); GC.Collect(2); GC.Collect(3); 

How can I find out what references does it still have? Why is it not collected?

Answer 1

Try using a memory profiler, (e.g. ants) it will tell you what is keeping the object alive. Trying to 2nd guess this type of problem is very hard.

Red-gate gives 14 days trial that should be more then enough time to tack down this problem and decide if a memory profiler provides you with long term value.

There are lots of other memory profilers on the market (e.g. .NET Memory Profiler) most of them have free trials, however I have found that the Red-Gate tools are easy to use, so tend try them first.

Answer 2

You'll have to use Windbg and Sosex extension.

The !DumpHeap and !GCRoot commands can help you to identify the instance, and all remaining references that keep it alive.