c# - windows 8 应用程序后退按钮导致导航失败

Question

我对开发 Windows 8 应用程序完全陌生，这将是我正在从事的第一个项目，所以请耐心等待。我从一个 gridview 模板开始，并尝试创建一个存储卡片和卡片组的类。因此，每个卡片组都是网格视图中的一个项目，通过单击卡片组，它将变为显示卡片组内容的详细视图。我的问题就在这里。当我导航到我的详细视图时，（到目前为止只显示一个标题）显示一个后退按钮，据我所知是自动处理的。但是，每当我按下后退按钮转到我的网格视图时，我都会遇到未处理的异常

Exception = {"Catastrophic failure (Exception from HRESULT: 0x8000FFFF (E_UNEXPECTED))"}

Message = "Windows.UI.Xaml.Controls.Frame.NavigationFailed was unhandled."

我的详细视图xaml和cs如下：

DetailPage.xaml.cs 使用 FlashcardBuddy.Data；使用系统；使用 System.Collections.Generic；使用 System.IO；使用 System.Linq；使用 Windows.Foundation；使用 Windows.Foundation.Collections；使用 Windows.UI.Xaml；使用 Windows.UI.Xaml.Controls；使用 Windows.UI.Xaml.Controls.Primitives；使用 Windows.UI.Xaml.Data；使用 Windows.UI.Xaml.Input；使用 Windows.UI.Xaml.Media；使用 Windows.UI.Xaml.Navigation；

// The Item Detail Page item template is documented at http://go.microsoft.com/fwlink/?LinkId=234232

namespace FlashcardBuddy
{

    public sealed partial class ItemDetailPage : FlashcardBuddy.Common.LayoutAwarePage
    {
        public ItemDetailPage()
        {
            this.InitializeComponent();
        }

        protected override void LoadState(Object navigationParameter, Dictionary<String, Object> pageState)
        {
            // Allow saved page state to override the initial item to display
            if (pageState != null && pageState.ContainsKey("SelectedItem"))
            {
                navigationParameter = pageState["SelectedItem"];
            }

            // TODO: Create an appropriate data model for your problem domain to replace the sample data
            var item = SampleDataSource.GetItem((String)navigationParameter);

            this.DefaultViewModel["Group"] = item;
            this.DefaultViewModel["Items"] = item.Items;
            //this.flipView.SelectedItem = item.Items[0];
        }


        protected override void SaveState(Dictionary<String, Object> pageState)
        {
            var selectedItem = (Card)this.flipView.SelectedItem;
            pageState["SelectedItem"] = selectedItem.id;
        }
    }
}

DetailPage.xaml：

<common:LayoutAwarePage
    x:Name="pageRoot"
    x:Class="FlashcardBuddy.ItemDetailPage"
    DataContext="{Binding DefaultViewModel, RelativeSource={RelativeSource Self}}"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:FlashcardBuddy"
    xmlns:data="using:FlashcardBuddy.Data"
    xmlns:common="using:FlashcardBuddy.Common"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d">

    <Page.Resources>

        <!-- Collection of items displayed by this page -->
        <CollectionViewSource
            x:Name="itemsViewSource"
            Source="{Binding Items}"
            d:Source="{Binding AllGroups[0].Items[0].Items, Source={d:DesignInstance Type=data:SampleDataSource, IsDesignTimeCreatable=True}}"/>
    </Page.Resources>

    <!--
        This grid acts as a root panel for the page that defines two rows:
        * Row 0 contains the back button and page title
        * Row 1 contains the rest of the page layout
    -->
    <Grid
        Style="{StaticResource LayoutRootStyle}"
        DataContext="{Binding Group}"
        d:DataContext="{Binding AllGroups[0], Source={d:DesignInstance Type=data:SampleDataSource, IsDesignTimeCreatable=True}}">

        <Grid.RowDefinitions>
            <RowDefinition Height="140"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>

        <!--
            The remainder of the page is one large FlipView that displays details for
            one item at a time, allowing the user to flip through all items in the chosen
            group
        -->


        <!-- Back button and page title -->
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto"/>
                <ColumnDefinition Width="*"/>
            </Grid.ColumnDefinitions>
            <Button x:Name="backButton" Click="GoBack" IsEnabled="{Binding Frame.CanGoBack, ElementName=pageRoot}" Style="{StaticResource BackButtonStyle}"/>
            <TextBlock x:Name="pageTitle" Text="{Binding frontText}" Style="{StaticResource PageHeaderTextStyle}" Grid.Column="1" IsHitTestVisible="false"/>
        </Grid>
        <FlipView x:Name="flipView" HorizontalAlignment="Left" Margin="0,0,0,0" Grid.Row="1" VerticalAlignment="Top" Width="1356"/>

        <VisualStateManager.VisualStateGroups>

            <!-- Visual states reflect the application's view state -->
            <VisualStateGroup x:Name="ApplicationViewStates">
                <VisualState x:Name="FullScreenLandscape"/>
                <VisualState x:Name="Filled"/>

                <!-- The back button respects the narrower 100-pixel margin convention for portrait -->
                <VisualState x:Name="FullScreenPortrait">
                    <Storyboard>
                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="backButton" Storyboard.TargetProperty="Style">
                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PortraitBackButtonStyle}"/>
                        </ObjectAnimationUsingKeyFrames>
                    </Storyboard>
                </VisualState>

                <!-- The back button and title have different styles when snapped -->
                <VisualState x:Name="Snapped">
                    <Storyboard>
                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="backButton" Storyboard.TargetProperty="Style">
                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SnappedBackButtonStyle}"/>
                        </ObjectAnimationUsingKeyFrames>
                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="pageTitle" Storyboard.TargetProperty="Style">
                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SnappedPageHeaderTextStyle}"/>
                        </ObjectAnimationUsingKeyFrames>
                    </Storyboard>
                </VisualState>
            </VisualStateGroup>
        </VisualStateManager.VisualStateGroups>
    </Grid>
</common:LayoutAwarePage>

我的主页的xaml和cs如下：

GroupedItemPage.xaml.cs 使用 FlashcardBuddy.Data；

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;

// The Grouped Items Page item template is documented at http://go.microsoft.com/fwlink/?LinkId=234231

namespace FlashcardBuddy
{
    /// <summary>
    /// A page that displays a grouped collection of items.
    /// </summary>
    public sealed partial class GroupedItemsPage : FlashcardBuddy.Common.LayoutAwarePage
    {
        public GroupedItemsPage()
        {
            this.InitializeComponent();
        }

        /// <summary>
        /// Populates the page with content passed during navigation.  Any saved state is also
        /// provided when recreating a page from a prior session.
        /// </summary>
        /// <param name="navigationParameter">The parameter value passed to
        /// <see cref="Frame.Navigate(Type, Object)"/> when this page was initially requested.
        /// </param>
        /// <param name="pageState">A dictionary of state preserved by this page during an earlier
        /// session.  This will be null the first time a page is visited.</param>
        protected override void LoadState(Object navigationParameter, Dictionary<String, Object> pageState)
        {
            // TODO: Create an appropriate data model for your problem domain to replace the sample data
            var sampleDataGroups = SampleDataSource.GetGroups((String)navigationParameter);
            this.DefaultViewModel["Groups"] = sampleDataGroups;
        }

        /// <summary>
        /// Invoked when an item within a group is clicked.
        /// </summary>
        /// <param name="sender">The GridView (or ListView when the application is snapped)
        /// displaying the item clicked.</param>
        /// <param name="e">Event data that describes the item clicked.</param>
        void ItemView_ItemClick(object sender, ItemClickEventArgs e)
        {
            // Navigate to the appropriate destination page, configuring the new page
            // by passing required information as a navigation parameter
            var itemId = ((Deck)e.ClickedItem).id;
            this.Frame.Navigate(typeof(ItemDetailPage), itemId);
        }

        private void itemGridView_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {

        }
    }
}

GroupedItemPage.xaml

    <Page.Resources>

        <!--
            Collection of grouped items displayed by this page, bound to a subset
            of the complete item list because items in groups cannot be virtualized
        -->
        <CollectionViewSource
            x:Name="groupedItemsViewSource"
            Source="{Binding Groups}"
            IsSourceGrouped="true"
            ItemsPath="TopItems"
            d:Source="{Binding AllGroups, Source={d:DesignInstance Type=data:SampleDataSource, IsDesignTimeCreatable=True}}"/>
    </Page.Resources>

    <!--
        This grid acts as a root panel for the page that defines two rows:
        * Row 0 contains the back button and page title
        * Row 1 contains the rest of the page layout
    -->
    <Grid Style="{StaticResource LayoutRootStyle}">
        <Grid.RowDefinitions>
            <RowDefinition Height="140"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>

        <!-- Horizontal scrolling grid used in most view states -->
        <GridView
            x:Name="itemGridView"
            AutomationProperties.AutomationId="ItemGridView"
            AutomationProperties.Name="Grouped Items"
            Grid.RowSpan="2"
            Padding="116,137,40,46"
            ItemsSource="{Binding Source={StaticResource groupedItemsViewSource}}"
            ItemTemplate="{StaticResource CustomDeckTempate}"
            SelectionMode="None"
            IsSwipeEnabled="false"
            IsItemClickEnabled="True"
            ItemClick="ItemView_ItemClick" SelectionChanged="itemGridView_SelectionChanged" Margin="0,10,0,-10">

            <GridView.ItemsPanel>
                <ItemsPanelTemplate>                        
                    <VirtualizingStackPanel Orientation="Horizontal"/>
                </ItemsPanelTemplate>
            </GridView.ItemsPanel>
            <GridView.GroupStyle>
                <GroupStyle>
                    <GroupStyle.HeaderTemplate>
                        <DataTemplate>
                            <Grid Margin="1,0,0,6">
                                <TextBlock
                                    AutomationProperties.Name="Group Title"
                                    Style="{StaticResource TextPrimaryGroupStyle}" 
                                    Text="{Binding frontText}" FontFamily="Global User Interface" FontSize="30"/>
                            </Grid>
                        </DataTemplate>
                    </GroupStyle.HeaderTemplate>
                    <GroupStyle.Panel>
                        <ItemsPanelTemplate>
                            <VariableSizedWrapGrid Orientation="Vertical" Margin="0,0,80,0"/>
                        </ItemsPanelTemplate>
                    </GroupStyle.Panel>
                </GroupStyle>
            </GridView.GroupStyle>
        </GridView>

        <!-- Vertical scrolling list only used when snapped -->
        <ListView
            x:Name="itemListView"
            AutomationProperties.AutomationId="ItemListView"
            AutomationProperties.Name="Grouped Items"
            Grid.Row="1"
            Visibility="Collapsed"
            Margin="0,-10,0,0"
            Padding="10,0,0,60"
            ItemsSource="{Binding Source={StaticResource groupedItemsViewSource}}"
            ItemTemplate="{StaticResource Standard80ItemTemplate}"
            SelectionMode="None"
            IsSwipeEnabled="false"
            IsItemClickEnabled="True"
            ItemClick="ItemView_ItemClick">

            <ListView.GroupStyle>
                <GroupStyle>
                    <GroupStyle.HeaderTemplate>
                        <DataTemplate>
                            <Grid Margin="7,7,0,0">
                                <Button
                                    AutomationProperties.Name="Group Title"
                                    Style="{StaticResource TextPrimaryButtonStyle}">
                                    <StackPanel Orientation="Horizontal">
                                        <TextBlock Text="{Binding frontText}" Margin="3,-7,10,10" Style="{StaticResource GroupHeaderTextStyle}" />
                                        <TextBlock Text="{StaticResource ChevronGlyph}" FontFamily="Segoe UI Symbol" Margin="0,-7,0,10" Style="{StaticResource GroupHeaderTextStyle}"/>
                                    </StackPanel>
                                </Button>
                            </Grid>
                        </DataTemplate>
                    </GroupStyle.HeaderTemplate>
                </GroupStyle>
            </ListView.GroupStyle>
        </ListView>

        <!-- Back button and page title -->
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto"/>
                <ColumnDefinition Width="*"/>
            </Grid.ColumnDefinitions>
            <Button x:Name="backButton" Click="GoBack" IsEnabled="{Binding Frame.CanGoBack, ElementName=pageRoot}" Style="{StaticResource BackButtonStyle}"/>
            <TextBlock x:Name="pageTitle" Text="{StaticResource AppName}" Grid.Column="1" IsHitTestVisible="false" Style="{StaticResource PageHeaderTextStyle}"/>
        </Grid>

        <VisualStateManager.VisualStateGroups>

            <!-- Visual states reflect the application's view state -->
            <VisualStateGroup x:Name="ApplicationViewStates">
                <VisualState x:Name="FullScreenLandscape"/>
                <VisualState x:Name="Filled"/>

                <!-- The entire page respects the narrower 100-pixel margin convention for portrait -->
                <VisualState x:Name="FullScreenPortrait">
                    <Storyboard>
                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="backButton" Storyboard.TargetProperty="Style">
                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PortraitBackButtonStyle}"/>
                        </ObjectAnimationUsingKeyFrames>

                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="itemGridView" Storyboard.TargetProperty="Padding">
                            <DiscreteObjectKeyFrame KeyTime="0" Value="96,137,10,56"/>
                        </ObjectAnimationUsingKeyFrames>
                    </Storyboard>
                </VisualState>

                <!--
                    The back button and title have different styles when snapped, and the list representation is substituted
                    for the grid displayed in all other view states
                -->
                <VisualState x:Name="Snapped">
                    <Storyboard>
                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="backButton" Storyboard.TargetProperty="Style">
                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SnappedBackButtonStyle}"/>
                        </ObjectAnimationUsingKeyFrames>
                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="pageTitle" Storyboard.TargetProperty="Style">
                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SnappedPageHeaderTextStyle}"/>
                        </ObjectAnimationUsingKeyFrames>

                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="itemListView" Storyboard.TargetProperty="Visibility">
                            <DiscreteObjectKeyFrame KeyTime="0" Value="Visible"/>
                        </ObjectAnimationUsingKeyFrames>
                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="itemGridView" Storyboard.TargetProperty="Visibility">
                            <DiscreteObjectKeyFrame KeyTime="0" Value="Collapsed"/>
                        </ObjectAnimationUsingKeyFrames>
                    </Storyboard>
                </VisualState>
            </VisualStateGroup>
        </VisualStateManager.VisualStateGroups>
    </Grid>
</common:LayoutAwarePage>

score 0 · Accepted Answer

我有一个类似的问题，我意识到覆盖OnNavigatedTo(NavigationEventArgs e), 而不调用基本实现是我做错了。在LayoutAwarePage那里做了一些重要的计算，所以错过它们会导致返回导航出现未处理的异常。

我想同样的事情也适用于protected override void OnNavigatedFrom(NavigationEventArgs e).

我知道我的解决方案并不直接适用于您，但这可能会作为其他人的参考。

score 0 · Accepted Answer

我想我只是不知道我在做什么。在玩了几天之后，我最终从头开始构建我的面板，而不是使用模板生成面板，并且效果很好。

c# - windows 8 应用程序后退按钮导致导航失败

2 回答 2

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