WPF - 在自定义 ComboBox 中绑定

Question

我正在尝试创建一个包含项目列表的自定义组合框，并且每个项目都有一个 add(+) 按钮，可以将该项目添加到“收藏夹”列表中：

XAML：

<UserControl x:Class=ComboBoxWithButton"
             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" 
             mc:Ignorable="d" d:DesignWidth="300" Height="25">
    <ComboBox 
    x:Name="ComboBoxBtn" 
    VerticalAlignment="Top" 
    HorizontalAlignment="Left" 
    Margin="0,0,0,-1" 
    Width="300" 
    ItemsSource="{Binding Source, RelativeSource={RelativeSource AncestorType=UserControl}}"
    SelectedItem="{Binding Path=Selected, Mode=TwoWay, RelativeSource={RelativeSource AncestorType=UserControl}}">
        <ComboBox.ItemTemplate>
            <DataTemplate>
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="Auto" />
                    </Grid.ColumnDefinitions>
                    <Label Content="{Binding}" Width="250" />
                    <Button Grid.Column="1" Command="{Binding CommandButton}"
                            CommandParameter="{Binding Path=Selected}">+</Button>
                </Grid>
            </DataTemplate>
        </ComboBox.ItemTemplate>
    </ComboBox>
</UserControl>

XAML.CS：

public IEnumerable Source
        {
            get { return (IEnumerable)GetValue(SourceProperty); }
            set { SetValue(SourceProperty, value); }
        }



    public static readonly DependencyProperty SourceProperty =
        DependencyProperty.Register("Source", typeof(IEnumerable), typeof(ComboBoxWithButton), new PropertyMetadata(null));


public static readonly DependencyProperty CommandProperty =
            DependencyProperty.Register("CommandButton", typeof(ICommand), typeof(ComboBoxWithButton), new PropertyMetadata(null));

        public ICommand CommandButton
        {
            get { return (ICommand)GetValue(CommandProperty); }
            set { SetValue(CommandProperty, value); }
        }

然后在我的主视图中，使用我拥有的组合框：

<controls:ComboBoxWithButton Source="{Binding AvailableClients}" Selected="{Binding SelectedClient, Mode=TwoWay}"
                                                       LostFocus="OnClientSelected"
                                                         CommandButton="{Binding AddFavoriteCommand}"/>

和：

AddFavoriteCommand = new RelayCommand<object>(AddToFavorite, f => true);

但这并没有触发我的功能“AddToFavorite”

Answer 1

该按钮位于 DataTemplate 内，因此每个按钮的 DataContext 与 UserControl 的 DataContext 不同。

您需要更改 Command 绑定以访问 UserControl 的 DataContext：

    <DataTemplate>
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto" />
                <ColumnDefinition Width="Auto" />
            </Grid.ColumnDefinitions>
            <Label Content="{Binding}" Width="250" />
            <Button Grid.Column="1" Command="{Binding CommandButton, RelativeSource={RelativeSource AncestorType=UserControl}}"
                    CommandParameter="{Binding Path=Selected}">+</Button>
        </Grid>
    </DataTemplate>