c# - Windows Phone - SyndicationFeed 问题

Question

我需要为学校项目申请 Windows Phone。我按照教程做了 RSS 阅读器，但它不起作用，我不知道为什么。

我遇到以下错误(运行后):

System.Windows.Data Error: BindingExpression path error: 'Items' property not found on 'Expression.Blend.SampleData.JustTestingData.JustTestingData' 'Expression.Blend.SampleData.JustTestingData.JustTestingData' (HashCode=12963143). BindingExpression: Path='Items' DataItem='Expression.Blend.SampleData.JustTestingData.JustTestingData' (HashCode=12963143); target element is 'System.Windows.Controls.ListBox' (Name='FeedContent'); target property is 'ItemsSource' (type 'System.Collections.IEnumerable')..

这是我的 .cs 文件:

public partial class MainPage : PhoneApplicationPage
{
    // Constructor
    public MainPage()
    {
        InitializeComponent();
        this.Loaded += new RoutedEventHandler(MainPage_Loaded);
    }

    public void MainPage_Loaded(object sender, RoutedEventArgs e)
    {
        WebClient wc = new WebClient();
        wc.OpenReadCompleted += new OpenReadCompletedEventHandler(wc_OpenReadCompleted);
        wc.OpenWriteAsync(new Uri("http://www.twojapogoda.pl/wiadomosci.xml"));
    }

    public void wc_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
    {
        SyndicationFeed feed;
        using (XmlReader reader = XmlReader.Create(e.Result))
        {
            feed = SyndicationFeed.Load(reader);
            FeedContent.ItemsSource = feed.Items;

        }
    }  
}

这是我的 xaml:

<phone:PhoneApplicationPage
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:Syndication="clr-namespace:System.ServiceModel.Syndication;assembly=System.ServiceModel.Syndication"
    x:Class="JustTestIt.MainPage"
    mc:Ignorable="d"
    SupportedOrientations="Portrait" Orientation="Portrait"
    shell:SystemTray.IsVisible="True">
    <phone:PhoneApplicationPage.Resources>
        <DataTemplate x:Key="ItemTemplate">
            <StackPanel>
                <CheckBox IsChecked="{Binding date, Mode=TwoWay}"/>
                <TextBlock Text="{Binding title}"/>
            </StackPanel>
        </DataTemplate>
        <DataTemplate x:Key="ItemTemplate1">
            <StackPanel>
                <CheckBox IsChecked="{Binding date, Mode=TwoWay}"/>
                <TextBlock Text="{Binding title}"/>
            </StackPanel>
        </DataTemplate>
        <DataTemplate x:Key="ItemTemplate2">
            <StackPanel Width="381">
                <TextBlock Text="{Binding title}" FontSize="32" Foreground="#FFFF8B00" Margin="0,0,10,0" FontFamily="Segoe WP Semibold"/>
                <TextBlock Text="{Binding date}" Foreground="White" FontFamily="Segoe WP Light"/>
            </StackPanel>
        </DataTemplate>
        <DataTemplate x:Key="SyndicationItemTemplate">
            <StackPanel>
                <TextBlock Text="{Binding Title.Text}"/>
            </StackPanel>
        </DataTemplate>
        <DataTemplate x:Key="SyndicationItemTemplate1">
            <StackPanel>
                <TextBlock Text="{Binding Title.Text}"/>
            </StackPanel>
        </DataTemplate>
        <DataTemplate x:Key="SyndicationItemTemplate2">
            <StackPanel>
                <TextBlock Text="{Binding Title.Text}"/>
            </StackPanel>
        </DataTemplate>
    </phone:PhoneApplicationPage.Resources>

    <phone:PhoneApplicationPage.FontFamily>
        <StaticResource ResourceKey="PhoneFontFamilyNormal"/>
    </phone:PhoneApplicationPage.FontFamily>
    <phone:PhoneApplicationPage.FontSize>
        <StaticResource ResourceKey="PhoneFontSizeNormal"/>
    </phone:PhoneApplicationPage.FontSize>
    <phone:PhoneApplicationPage.Foreground>
        <StaticResource ResourceKey="PhoneForegroundBrush"/>
    </phone:PhoneApplicationPage.Foreground>
    <Grid x:Name="LayoutRoot" Background="Transparent" DataContext="{Binding Source={StaticResource JustTestingData}}">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <phone:Panorama Foreground="White" FontFamily="Segoe WP Light" Background="Black">
            <phone:Panorama.Title>
                <TextBlock Text="JustTest it!"/>
            </phone:Panorama.Title>
            <phone:PanoramaItem x:Name="headers" CacheMode="{x:Null}" Header="">
                <phone:PanoramaItem.RenderTransform>
                    <TranslateTransform/>
                </phone:PanoramaItem.RenderTransform>
                <Grid Margin="0">
                    <ListBox HorizontalAlignment="Left" ItemTemplate="{StaticResource ItemTemplate2}" ItemsSource="{Binding Collection}" VerticalAlignment="Top" Width="410"/>
                </Grid>
            </phone:PanoramaItem>
            <phone:PanoramaItem x:Name="articles" CacheMode="{x:Null}" Header="" d:DataContext="{d:DesignData /SampleData/SyndicationFeedSampleData.xaml}">
                <phone:PanoramaItem.RenderTransform>
                    <TranslateTransform/>
                </phone:PanoramaItem.RenderTransform>
                <Grid>
                    <ListBox x:Name="FeedContent" HorizontalAlignment="Left" ItemTemplate="{StaticResource SyndicationItemTemplate2}" ItemsSource="{Binding Items}" VerticalAlignment="Top"/>
                </Grid>
            </phone:PanoramaItem>
        </phone:Panorama>
    </Grid>
</phone:PhoneApplicationPage>

我做错了什么，没有从源加载任何内容？我正在使用 blend 和 visual studio 2013。

Answer 1

你的错误在这一行

 <ListBox x:Name="FeedContent" HorizontalAlignment="Left" ItemTemplate="{StaticResource 
SyndicationItemTemplate2}" ItemsSource="{Binding Items}" VerticalAlignment="Top"/>

错误就在这里

ItemsSource="{Binding Items}" 

它说它看不到名为“Items”的属性

这可能有多种原因。我需要查看您所有的 CS 文件才能为您提供更具体的答案

如果这就是您的所有 cs 文件，那么就会有一个巨大的问题。你没有属性(property)....

您可以先添加这个。

public ObservableCollection Items {get;set;}

此外，您似乎没有设置数据上下文。

在 InitializeComponent 上面执行此操作。

this.DataContext = this;

编辑

根据对您的 CS 文件的进一步评估和一些创造性的推断，您似乎需要执行以下操作。

使您的 SyndicationFeed 对象成为一个属性

private SyndicationFeed _feed;
public SyndicationFeed feed {get{return _feed;} set{_feed = value; OnPropertyChanged("feed");} 

将您的数据上下文设置为

this.Datacontext = feed;

实现

INotifyPropertyChanged

添加属性 Changed 事件处理程序

     protected void OnPropertyChanged(string name)
      {
          PropertyChangedEventHandler handler = PropertyChanged;
          if (handler != null)
          {
              handler(this, new PropertyChangedEventArgs(name));
          }
      }

我很确定您的 SyndicationFeed 类也需要实现 INotifyPropertyChanged。

以上两种解决方案中的任何一种都应该有效。