关于搜索问题【C#】

Question

软件打开后搜索很正常，软件没运行，点击搜索能调出软件的搜索页面，但是输入内容后搜索，程序就崩溃了，怎么回事啊？

而且我新建模版的搜索页面，没有这个问题，难道是我写的搜索页面有问题？

下面是我的app.xaml.cs 的代码

 /// <summary>
        /// Invoked when the application is activated to display search results.
        /// </summary>
        /// <param name="args">Details about the activation request.</param>
        protected  override  void OnSearchActivated(Windows.ApplicationModel.Activation.SearchActivatedEventArgs args)
        {
            if (args.PreviousExecutionState == ApplicationExecutionState.NotRunning ||
                args.PreviousExecutionState == ApplicationExecutionState.ClosedByUser ||
                args.PreviousExecutionState == ApplicationExecutionState.Terminated)
            {
                SearchPane.GetForCurrentView().SuggestionsRequested += OnSuggestionsRequested;
            }
            var previousContent = Window.Current.Content;
            var frame = previousContent as Frame;
            if (frame == null)
            {               
                frame = new Frame();               
            }

            Window.Current.Content = frame;               
            Window.Current.Activate();
            frame.Navigate(typeof(Views.SearchView), args.QueryText);
        }

下面是我搜索页面的LoadState代码

 /// <summary>
        /// 使用在导航过程中传递的内容填充页。在从以前的会话
        /// 重新创建页时，也会提供任何已保存状态。
        /// </summary>
        /// <param name="navigationParameter">最初请求此页时传递给
        /// <see cref="Frame.Navigate(Type, Object)"/> 的参数值。
        /// </param>
        /// <param name="pageState">此页在以前会话期间保留的状态
        /// 字典。首次访问页面时为 null。</param>
        protected override void LoadState(Object navigationParameter, Dictionary<String, Object> pageState)
        {
            if (pageState == null)
            {
                if (SearchVM == null)
                {
                    SearchVM = new SearchViewModel();
                }            
                if (navigationParameter != null)
                {
                    string strCommmet = navigationParameter as string;
                    if (!string.IsNullOrEmpty(strCommmet))
                    {
                        this.updateTitle(strCommmet);
                        SearchVM.strSearchComment = strCommmet;                       
                        SearchVM.Search();
                    }
                }
            }
            else
            {
                SearchVM = pageState["VMDATA"] as SearchViewModel;
               
            }

            this.DataContext = SearchVM;
        }

麻烦大家给看看，哪里出问题了？

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