asp net Find all controls

private void GetControlList(ControlCollection controlCollection, List resultCollection) where T : Control
{
       foreach (Control control in controlCollection)
       {
          if (control is T) // This is cleaner
               resultCollection.Add((T)control);
           if (control.HasControls())
               GetControlList(control.Controls, resultCollection);
       }
}

Page: PreInit
Control: Init
Page: Init
Page: InitComplete
Page: PreLoad
Page: Load
Control: Load
Page: LoadComplete
Page: PreRender
Control: PreRender
Page: PreRenderComplete
Page: SaveStateComplete
Page: RenderControl
Page: Render
Control: RenderControl
Control: Unload
Control: Dispose
Page: Unload
Page: Dispose