我有一個(gè)從SQLite數(shù)據(jù)庫(kù)填充的列表視圖。對(duì)于該listview，構(gòu)造了一種方法，用于在敲擊listview元素時(shí)進(jìn)行處理：xaml單元格：<ListView x:Name="CalculationListview" ItemsSource="{Binding Calculation}" HasUnevenRows="true" IsPullToRefreshEnabled="true" Refreshing="Handle_Refreshing">    <ListView.ItemTemplate>        <DataTemplate>            <ViewCell Tapped="Handle_Tapped">                <ViewCell.ContextActions>                    <MenuItem Text="Delete" IsDestructive="True" Clicked="Handle_Clicked" />                </ViewCell.ContextActions>                <StackLayout>                    <Label Text="{Binding Qty}">                    </Label>                    <Label Text="{Binding Note}">                    </Label>                    <Label Text="{Binding Id}">                    </Label>                </StackLayout>            </ViewCell>        </DataTemplate>    </ListView.ItemTemplate></ListView>C＃async void Handle_Tapped(object sender, System.EventArgs e){    var viewCellSelected = sender as MenuItem;    var calculation = viewCellSelected?.BindingContext as Calculation;    var page = new ViewSaved(calculation);    await Navigation.PushModalAsync(page);}如您所見(jiàn)，我想Calculation從給定的listview元素中檢索對(duì)象并將該對(duì)象發(fā)送到名為的新視圖ViewSaved。不幸的是，我的變量calculation仍然為null，并且在將空對(duì)象發(fā)送到新視圖時(shí)收到異常。我懷疑這sender as MenuItem;是問(wèn)題所在。