#427 – Finalizer Gotchas

The idea of the finalizer in .NET is that you can override the Object.Finalize method, called by the garbage collector when it’s releasing memory for an object, and you can do any required cleanup of unmanaged resources.

There are several things to keep in mind if you want to write a finalizer (done in C# using the destructor syntax):

  • You can’t predict when your finalizer is called
  • The finalizer might never get called at all
  • The order that finalizers are called in is unpredictable.  You therefore can’t assume that any other managed object that your object references still exists, or is in a known state.
  • Garbage collection will take longer if you have objects with finalizers