c# remove all event handler from BackgroundWorker.DoWork by Reflection

i am helped by this link -How to remove all event handlers from a control

yep i succeed remove all event handler from control and form.

but i have failed in BackgroundWorker.

this is my code.

    void ReadingCompleted()
    {
        //find fields
        List<FieldInfo> liField=typeof(BackgroundWorker).GetFields(BindingFlags.Static | BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.GetField | BindingFlags.Public).ToList();

        foreach(FieldInfo field in liField)
        {
            txtbox_log.Text += field.Name + "\r\n";
        }
        //below output list 
        //canCancelWorker
        //workerReportsProgress
        //cancellationPending
        //isRunning
        //asyncOperation
        //threadStart
        //operationCompleted
        //progressReporter
        //doWorkKey
        //runWorkerCompletedKey
        //progressChangedKey

        //remove all eventhandler
        object key = typeof(BackgroundWorker).GetField("doWorkKey", BindingFlags.NonPublic | BindingFlags.Static);

        EventHandlerList events = (EventHandlerList)typeof(Component)
        .GetProperty("Events", BindingFlags.NonPublic | BindingFlags.Instance)
        .GetValue(this, null);
        events.RemoveHandler(key, events[key]);
        waitForm.Close();
    }