C# ItemsSource的DependencyProperty

我有一个XAML，比如：

<UserControl x:Class="Book.CustomControls.HeaderedComboBox"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             DataContext="{Binding RelativeSource={RelativeSource Self}}"
             Width="200" Height="50">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        <TextBlock Grid.Row="0" Margin="2,2" VerticalAlignment="Center" Text="{Binding Header}" FontWeight="{Binding HeaderFontWeight}"/>
        <ComboBox Grid.Row="1" Margin="2,2" VerticalAlignment="Center" ItemsSource="{Binding ItemsSource, UpdateSourceTrigger=PropertyChanged}"
                  SelectedItem="{Binding SelectedItem, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
    </Grid>
</UserControl>

我尝试在任何窗口中使用此UserControl

<customControls:HeaderedComboBox Header="Category" ItemsSource="{Binding Categories}"/>

类别只是一个可观察的集合

不幸的是，我在组合框中没有看到任何项目。目前我不知道我做错了什么。有什么想法吗

System.Windows.Data Error: 40 : BindingExpression path error: 'Categories' property not found on 'object' ''HeaderedComboBox' (Name='')'. BindingExpression:Path=Categories; DataItem='HeaderedComboBox' (Name=''); target element is 'HeaderedComboBox' (Name=''); target property is 'ItemsSource' (type 'IEnumerable')

您的DataContext设置为HeaderedCombobox，系统正在查找类别。属性头工作，因为您将文本放入其中而没有绑定。可能的解决办法

<Window x:Class="WpfApplication5.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525"
    xmlns:local="clr-namespace:WpfApplication5" Name="window">
<Grid>
    <local:HeaderedComboBox Header="Category" ItemsSource="{Binding ElementName=window, Path=DataContext.Categories}"/>
</Grid>

<Window x:Class="WpfApplication5.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525"
    xmlns:local="clr-namespace:WpfApplication5" Name="window">
<Grid>
    <local:HeaderedComboBox Header="Category" ItemsSource="{Binding ElementName=window, Path=DataContext.Categories}"/>
</Grid>