wpf - 在用户控件中绑定 ObservableCollection 依赖属性

问题描述

我有一个承载 TreeView 的 UserControl，该 TreeView 具有从自定义类的 ObservableCollection 继承的自定义集合。我正在尝试使用 ViewModel 中的依赖属性绑定到一个属性，而我已经证明该过程适用于另一个在此处不起作用的属性。

我确定这是我错过的一些愚蠢的事情，但我一直在转圈，有人能发现我的错误吗？

用户控件 XAML：

<UserControl
x:Class="FileExplorer.TreeViewUserControl"
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:fe="clr-namespace:WpfControlLibrary.FileExplorer"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
x:Name="FileExplorer"
d:DesignHeight="300"
d:DesignWidth="400"
mc:Ignorable="d">
<TreeView
    BorderThickness="0"
    ItemsSource="{Binding FileSystem, RelativeSource={RelativeSource AncestorType=UserControl}}"
    TreeViewItem.Collapsed="TreeView_Collapsed"
    TreeViewItem.Expanded="TreeView_Expanded"
    VirtualizingStackPanel.IsVirtualizing="True"
    VirtualizingStackPanel.VirtualizationMode="Recycling">
    <TreeView.ItemTemplate>
        <HierarchicalDataTemplate DataType="{x:Type fe:FileSystemObject}" ItemsSource="{Binding Items}">
            <StackPanel Margin="0,2" Orientation="Horizontal">
                <Image
                    Width="14"
                    Margin="2"
                    Source="{Binding Image}"
                    Stretch="Fill" />
                <TextBlock
                    VerticalAlignment="Center"
                    FontSize="{StaticResource FontSizeSmall}"
                    Text="{Binding Name}" />
            </StackPanel>
        </HierarchicalDataTemplate>
    </TreeView.ItemTemplate>
</TreeView>

UserControl 背后的代码：

    Namespace FileExplorer
    Public Class TreeViewUserControl
        Inherits UserControl

#Region "Constructors"
        Public Sub New()

            ' This call is required by the designer.
            InitializeComponent()

            ' Add any initialization after the InitializeComponent() call.
            Me.DataContext = Me
        End Sub

#End Region

#Region "Properties"

        Public Shared ReadOnly FileSystemProperty As DependencyProperty = DependencyProperty.Register("FileSystem", GetType(FileSystemObjectCollection), GetType(TreeViewUserControl))

        Public Property FileSystem As FileSystemObjectCollection
            Get
                Return CType(GetValue(FileSystemProperty), FileSystemObjectCollection)
            End Get
            Set(ByVal value As FileSystemObjectCollection)
                SetValue(FileSystemProperty, value)
                FileExplorer.UpdateLayout()
            End Set
        End Property

#End Region

   Private Function GetFileSystemInfo(ByVal root As String) As FileSystemObjectCollection
        Dim items As New FileSystemObjectCollection

        ' Parse all the directories at the path
        For Each dir As String In Directory.GetDirectories(root)
            items.Add(New FileSystemObject(dir, root))
        Next

        ' Parse all the file at the path
        For Each file As String In Directory.GetFiles(root)
            items.Add(New FileSystemObject(file, root))
        Next

        Return items
    End Function

    Private Sub TreeView_Collapsed(sender As Object, e As RoutedEventArgs)
        Dim node As TreeViewItem = CType(e.OriginalSource, TreeViewItem)
        Dim fs As FileSystemObject = CType(node.DataContext, FileSystemObject)
        fs.Clear()
    End Sub

    Private Sub TreeView_Expanded(sender As Object, e As RoutedEventArgs)
        Dim node As TreeViewItem = CType(e.OriginalSource, TreeViewItem)
        Dim fs As FileSystemObject = CType(node.DataContext, FileSystemObject)
        If Not fs.HasChildren Then Exit Sub
        fs.Items = GetFileSystemInfo(fs.FullName)
    End Sub

    End Class

End Namespace

主窗口 XAML：

<Window
    x:Class="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:fe="clr-namespace:WpfControlLibrary.FileExplorer;assembly=WpfControlLibrary"
    xmlns:local="clr-namespace:ModStudio.Client"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:vm="clr-namespace:ModStudio.Client.ViewModels"
    Title="MainWindow"
    d:DesignHeight="600"
    d:DesignWidth="800"
    WindowStartupLocation="CenterOwner"
    WindowState="Maximized"
    mc:Ignorable="d">

    <Window.Resources>
        <vm:MainWindowViewModel x:Key="MainWindowViewModel" />
    </Window.Resources>

    <Grid>
        <fe:TreeViewUserControl DataContext="{StaticResource MainWindowViewModel}" FileSystem="{Binding ApplicationExplorer}" />
    </Grid>
</Window>

在后面的代码中将MainWindow其DataContext设置为 ViewModel 的新实例。MainWindowViewModel有一个名为的属性，ApplicationExplorer它是的一个实例FileSystemObjectCollection。如前所述FileSystemObjectCollection，继承自ObservableCollection(Of FileSystemObject). AFileSystemObject实现INotifyPropertyChanged。如果我更改ApplicationExplorer属性，控件将保持空白。

我在这里故意省略了一些代码，但如果需要可以添加它们。

标签： wpfuser-controlstreeviewobservablecollectiondependency-properties

wpf - 在用户控件中绑定 ObservableCollection 依赖属性

问题描述

解决方案

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