在我的用户控件中附加的属性绑定失败

本文关键字：属性 绑定 失败 我的 用户 控件 | 更新日期: 2023-09-27 18:20:20

我有一个UsersControl.xaml

<UserControl x:Name="userControl" x:Class="Lloyd.Shared.Controls.UsersControl"
         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:Interactivity="http://schemas.microsoft.com/expression/2010/interactivity"
         xmlns:Behaviors="clr-namespace:Lloyd.Shared.Controls.Behaviors"
         xmlns:local="clr-namespace:Lloyd.Shared.Controls"
         mc:Ignorable="d" DataContext="{Binding Mode=OneWay, RelativeSource={RelativeSource Self}}"
         d:DesignHeight="300" d:DesignWidth="300">
<Interactivity:Interaction.Behaviors>
    <Behaviors:ImportUsersOnLoadedBehavior />
</Interactivity:Interaction.Behaviors>
<DockPanel LastChildFill="True">
    <Label Content="账号" DockPanel.Dock="Top" FontSize="18.667" />
    <StackPanel Orientation="Horizontal" DockPanel.Dock="Bottom" HorizontalAlignment="Right">
        <Button x:Name="AddAccountButton" Height="26" Width="80" Content="添加" Margin="5" Command="{Binding AddUserCommand}" />
        <Button x:Name="ImportAccountsButton" Height="26" Width="80" Content="导入" Margin="5" Command="{Binding ImportUsersCommand}"/>
        <Button x:Name="DeleteAccountButton" Height="26" Width="80" Content="删除" Margin="5" Command="{Binding RemoveUsersCommand}"/>
    </StackPanel>
    <ListView x:Name="accountListbox" Margin="5" BorderThickness="1" BorderBrush="{DynamicResource AccentColorBrush}" ItemsSource="{Binding UsersCollection}"/>
</DockPanel>

背后的代码

public partial class UsersControl : UserControl
{
    public static ObservableCollection<User> GetUsersCollection(DependencyObject obj)
    {
        return (ObservableCollection<User>)obj.GetValue(UsersCollectionProperty);
    }
    public static void SetUsersCollection(DependencyObject obj, ObservableCollection<User> value)
    {
        obj.SetValue(UsersCollectionProperty, value);
    }
    // Using a DependencyProperty as the backing store for UsersCollection.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty UsersCollectionProperty =
        DependencyProperty.RegisterAttached("UsersCollection", typeof(ObservableCollection<User>), typeof(UsersControl), new FrameworkPropertyMetadata(null,FrameworkPropertyMetadataOptions.AffectsRender));

}

我在MainWindow.xaml中使用这个UsersControl，并将UsersCollection绑定到主窗口的DataContext。

<Controls:MetroWindow x:Class="ZggwwDocuments.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:c="clr-namespace:Lloyd.Shared.Controls;assembly=Lloyd.Shared.Controls"
    xmlns:vm="clr-namespace:ZggwwDocuments.ViewModels"
    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:local="clr-namespace:ZggwwDocuments"
    mc:Ignorable="d"
    Title="MainWindow" Height="350" Width="697.514">
<Controls:MetroWindow.DataContext>
    <vm:MainWindowViewModel/>
</Controls:MetroWindow.DataContext>
<Grid Margin="5">
    <c:UsersControl UsersCollection="{Binding Users}"  />
</Grid>

我在MainWindow上设置了断点，它的DataContext和Users属性不为null。但是MainWindow.DataContext.Users和UsersControl.UsersCollection之间的绑定失败。以下内容来自输出窗口

System.Windows.Data错误：40:BindingExpression路径错误：在"对象"UsersControl"（名称="userControl"）上找不到"Users"属性。BindingExpression:Path=Users；DataItem='UsersControl'（名称='userControl'）；目标元素是"UsersControl"（名称="userControl"）；目标属性为"UsersCollection"（类型为"ObservableCollection"1"）

UsersControl.xaml.cs中的GetUsersCollection（DependencyObject obj）始终返回null

在我的用户控件中附加的属性绑定失败

尝试

ItemsSource="{Binding RelativeSource={RelativeSource AncestorType={x:Type c:UsersControl}}, Path=UsersCollection}"

或者，你可以聪明一点；

<DockPanel LastChildFill="True">
    <Label Content="账号" DockPanel.Dock="Top" FontSize="18.667" />
    <StackPanel Orientation="Horizontal" DockPanel.Dock="Bottom" HorizontalAlignment="Right">
        <Button x:Name="AddAccountButton" Height="26" Width="80" Content="添加" Margin="5" Command="{Binding AddUserCommand}" />
        <Button x:Name="ImportAccountsButton" Height="26" Width="80" Content="导入" Margin="5" Command="{Binding ImportUsersCommand}"/>
        <Button x:Name="DeleteAccountButton" Height="26" Width="80" Content="删除" Margin="5" Command="{Binding RemoveUsersCommand}"/>
    </StackPanel>
    <ListView x:Name="accountListbox" Margin="5" BorderThickness="1" BorderBrush="{DynamicResource AccentColorBrush}" ItemsSource="{Binding UsersCollection}"/>
</DockPanel>

把它塞进去；

<UserControl.Template>
   <ControlTemplate TargetType="{x:Type UserControl}">
      (paste it here)
   </ControlTemplate>
</UserControl.Template>

然后将绑定更改为；

{Binding RelativeSource={RelativeSource TemplatedParent}, Path=UsersCollection}

就我个人而言，我建议使用这种方法，而不是第一种方法，因为绑定更快，不太容易…"问题'。。。这也意味着你要覆盖用户控件的模板，使其成为你真正想要的样子，而不仅仅是在现有模板中转储一些XAML。

尝试调用您的附加属性，如下所示：

<c:UsersControl UsersControl.UsersCollection="{Binding Users}"  />
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