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好的，我现在将尝试解释我的练习。这是我的 PageOverzicht.xaml，并且此代码有效。它给了我一个下拉列表，其中包含花朵的颜色（蓝色、橙色、白色……）。现在数据上下文被硬编码以找到白色的花朵。目标：通过后面的代码设置数据上下文，以便下一步可以使用 selectionchanged 属性选择具有所选颜色的花朵。

所以现在我需要先设置datacontext，这样它就不会被硬编码为白色。列表框由xml节点、白色植物的名称组成，使用PageOverzicht的Page_Loaded方法。

<Page x:Class="Planten_BIS.PageOverzicht"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
      xmlns:local="clr-namespace:Planten_BIS"
      mc:Ignorable="d"
      d:DesignHeight="450" d:DesignWidth="800"
      Title="PageOverzicht">

    <Page.Resources>
        <XmlDataProvider x:Key="CatalogDataSource" XPath="catalog" Source="data/catalogus.xml"></XmlDataProvider>
        <DataTemplate x:Key="listItemTemplate">
            <StackPanel Orientation="Horizontal">
                <TextBlock Name="ImageName" Visibility="Collapsed" Text="{Binding XPath=botanical, StringFormat=images/{0}.jpg}" />

                <Border BorderBrush="white" BorderThickness="2" CornerRadius="10" Background="{StaticResource AchtergrondKleur}">
                    <Rectangle Width="100" Height="100" RadiusX="10" RadiusY="10">
                        <Rectangle.Fill>
                            <ImageBrush ImageSource="{Binding Text, ElementName=ImageName}" />
                        </Rectangle.Fill>
                    </Rectangle>
                </Border>
                <StackPanel Orientation="Vertical" Margin="10" VerticalAlignment="Center">
                    <ListBoxItem Content="{Binding XPath=common}"/>
                    <ListBoxItem Content="{Binding XPath=price}"/>
                </StackPanel>
            </StackPanel>
        </DataTemplate>
    </Page.Resources>
    <Grid>
        <ListBox Name="ListboxFlowers" Background="Transparent" Foreground="white" DataContext="{Binding Source={StaticResource CatalogDataSource}, XPath=color[@name\=\'White\']/plant}" ItemsSource="{Binding}" ItemTemplate="{StaticResource listItemTemplate}"></ListBox>
    </Grid>
</Page>

数据来自xml的一小部分：

<?xml version="1.0" encoding="ISO8859-1" ?>
<catalog>
  <color name="White">
    <plant>
      <common>Jacob's Ladder</common>
      <botanical>Polemonium caeruleum i</botanical>
      <zone>Annual</zone>
      <light>Shade</light>
      <price>$9.26</price>
      <availability>022199</availability>
      <color>white</color>
      <description>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</description>
    </plant>

带有 PageOverzicht 框架的主窗口：

<Window x:Class="Planten_BIS.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:scm="clr-namespace:System.ComponentModel;assembly=WindowsBase"
        xmlns:local="clr-namespace:Planten_BIS"
        mc:Ignorable="d"
        Title="Plant Catalog" Height="600" Width="800">
    <Window.Resources>
        <Style x:Key="buttonStyle" TargetType="Button">
            <Setter Property="Background" Value="{StaticResource ToolBarKleur}" />
            <Setter Property="BorderBrush" Value="{StaticResource RandKleur}" />
            <Setter Property="Foreground" Value="{StaticResource LetterKleur}" />
            <Setter Property="Height" Value="30" />
            <Setter Property="Margin" Value="6" />
        </Style>
        <Style x:Key="comboStyle" TargetType="ComboBox">
            <Setter Property="Background" Value="{StaticResource ToolBarKleur}" />
            <Setter Property="BorderBrush" Value="{StaticResource RandKleur}" />
            <Setter Property="Foreground" Value="{StaticResource LetterKleur}" />
            <Setter Property="Width" Value="100" />
            <Setter Property="Height" Value="30" />
            <Setter Property="Margin" Value="6" />
        </Style>
        <XmlDataProvider x:Key="CatalogDataSource" XPath="catalog" Source="data/catalogus.xml"></XmlDataProvider>
        <CollectionViewSource x:Key="cvsColors" Source="{StaticResource CatalogDataSource}">
            <CollectionViewSource.SortDescriptions>
                <scm:SortDescription PropertyName="color" />
            </CollectionViewSource.SortDescriptions>
        </CollectionViewSource>
        <DataTemplate x:Key="comboItemTemplate">
            <Label Content="{Binding XPath=@name}"/>
        </DataTemplate>

    </Window.Resources>
    <DockPanel LastChildFill="True">
        <ToolBar Background="{StaticResource ToolBarKleur}" DockPanel.Dock="Top">
            <Button Style="{StaticResource buttonStyle}" Content="Backward"></Button>
            <Button Style="{StaticResource buttonStyle}" Content="Forward"></Button>
            <ComboBox Style="{StaticResource comboStyle}" SelectedIndex="0"  ItemsSource="{Binding Source={StaticResource CatalogDataSource}, XPath=color}" ItemTemplate="{StaticResource comboItemTemplate}"></ComboBox>
        </ToolBar>
        <Frame Source="PageOverzicht.xaml" Name="frame" NavigationUIVisibility="Hidden">
            <Frame.Background>
                <ImageBrush ImageSource="assets/background.jpg" Stretch="UniformToFill"/>
            </Frame.Background>
        </Frame>
    </DockPanel>
</Window>
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1 回答 1

0

数据源处理应该移动到一个控件，它是 和 的共同父级ComboBox，Frame在这种情况下，我选择了MainWindow.

您应该将所需的DependecyProperty定义添加到MainWindow可用于 和 的数据绑定的ComboBox.ItemsSource中。ComboBox.SelectedItemFrame.DataContext

对于 XML 处理，我将 XMLDataProvider 替换为XElement允许 LINQ To XML 的数据源，以便在 C# 中轻松过滤或遍历 XML 对象树。

现在ComboBox绑定到XElement表示 XMLcolor节点的项目集合。所选ComboBox项目是单个 XMLcolor元素。的后代plant节点color用于设置Frame.DataContext，继承给Page.DataContext。现在ListBox将其直接Page绑定到属性。或者，例如，如果您需要将 设置为不同的东西，您可以让遍历可视化树以找到of的使用。ItemsSourceDataContextMainWindow.PlantsOfSelectedColorPage.DataContextBindingMainWindow.PlantsOfSelectedColorRelativeSource FindAncestorBinding.RelativeSourceListBox.ItemsSource

主窗口.xaml.cs

public partial class MainWindow : Window
{
  public static readonly DependencyProperty PlantColorNodesProperty = DependencyProperty.Register(
    "PlantColorNodes",
    typeof(IEnumerable<XElement>),
    typeof(MainWindow),
    new PropertyMetadata(default(IEnumerable<XElement>)));

  public IEnumerable<XElement> PlantColorNodes
  {
    get => (IEnumerable<XElement>) GetValue(MainWindow.PlantColorNodesProperty);
    set => SetValue(MainWindow.PlantColorNodesProperty, value);
  }

  public static readonly DependencyProperty SelectedPlantColorNodeProperty = DependencyProperty.Register(
    "SelectedPlantColorNode",
    typeof(XElement),
    typeof(MainWindow),
    new PropertyMetadata(default(XElement), OnSelectedPlantColorNodeChanged));

  public XElement SelectedPlantColorNode
  {
    get => (XElement) GetValue(MainWindow.SelectedPlantColorNodeProperty);
    set => SetValue(MainWindow.SelectedPlantColorNodeProperty, value);
  }

  public static readonly DependencyProperty PlantsOfSelectedColorProperty = DependencyProperty.Register(
    "PlantsOfSelectedColor",
    typeof(IEnumerable<XElement>),
    typeof(MainWindow),
    new PropertyMetadata(default(IEnumerable<XElement>)));

  public IEnumerable<XElement> PlantsOfSelectedColor
  {
    get => (IEnumerable<XElement>) GetValue(MainWindow.PlantsOfSelectedColorProperty);
    set => SetValue(MainWindow.PlantsOfSelectedColorProperty, value);
  }

  public MainWindow()
  {
    InitializeComponent();

    // Open XML an collect all 'color' nodes
    this.PlantColorNodes = XElement.Load("data/catalogus.xml").Elements("color");
  }

  private static void OnSelectedPlantColorNodeChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
  {
    var colorNode = e.NewValue as XElement;

    // Get the 'plant' child nodes of the selected 'color' node
    (d as MainWindow).PlantsOfSelectedColor = colorNode.Elements();
  }
}

主窗口.xaml

<Window>
  <DockPanel LastChildFill="True">
    <ComboBox ItemsSource="{Binding RelativeSource={RelativeSource AncestorType=MainWindow}, Path=PlantColorNodes}" 
              SelectedItem="{Binding RelativeSource={RelativeSource AncestorType=MainWindow}, Path=SelectedPlantColorNode}">
      <ComboBox.ItemTemplate>
        <DataTemplate>
          <TextBlock Text="{Binding Attribute[name].Value}" />
        </DataTemplate>
      </ComboBox.ItemTemplate>
    <ComboBox>
    <Frame DatContext="{Binding RelativeSource={RelativeSource AncestorType=MainWindow}, Path=PlantsOfSelectedColor}"
           Source="PageOverzicht.xaml" />
    </DockPanel>
</Window>

PageOverzicht.xaml

<Page>
  <ListBox ItemsSource="{Binding}">
    <ListBox.ItemTemplate>
      <DataTemplate  >
        <StackPanel Orientation="Horizontal">
          <TextBlock Text="{Binding Element[botanical].Value}" />
          <TextBlock Text="{Binding Element[common].Value}"/>
          <TextBlock Text="{Binding Element[price].Value}"/>          
        </StackPanel>
      </DataTemplate>
    </ListBox.ItemTemplate>
  </ListBox>
</Page>
于 2020-03-15T19:45:44.743 回答