#429 – Use the Dispose Pattern for Deterministic Destruction

You can implement a finalizer in a class to explicitly release unmanaged resources before an object’s memory is freed.  Drawbacks of this approach include:

  • You don’t control when the object’s resources are cleaned up
  • A finalizer can’t make use of any other managed objects  (they may have already been finalized)

Another pattern for releasing unmanaged resources is for a class to implement the IDisposable interface by providing a Dispose method.  Dispose is meant to clean up the object’s resources when it’s called.  A client of the class can decide exactly when it wants to release the object’s resources (deterministic destruction).  Benefits of this pattern include:

  • Can release resources earlier, not waiting for finalization
  • Dispose logic can make use of other managed resources
    public class Dog : IDisposable
    {
        public void Dispose()
        {
            // Release unmanaged resources here

            // Note: need logic to prevent double disposal, etc.
        }
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