/// <summary>
        /// Saves any state that was modified after the TrackViewState method was invoked
        /// 并在SaveViewState之前,将ViewState中所有IStateManager类型项转换为可序列化的ViewSateItemInternal类型项
        /// 以及在SaveViewState之后,将ViewState中所有ViewSateItemInternal类型项恢复成IStateManager类型项
        /// </summary>
        /// <returns>返回服务器控件的当前视图状态</returns>
        /// <remarks>
        /// Saves any state that was modified after the TrackViewState method was invoked
        /// 并在SaveViewState之前,将ViewState中所有IStateManager类型项转换为可序列化的ViewSateItemInternal类型项
        /// 以及在SaveViewState之后,将ViewState中所有ViewSateItemInternal类型项恢复成IStateManager类型项
        /// </remarks>
        protected override object SaveViewState()
        {
            ViewState.PreSaveViewState();
            object o = base.SaveViewState();

            ViewState.AfterSavedViewState();

            return(o);
        }