silverlight - EventTrigger 在 MVVM 中的 ItemsControl 中不起作用

Question

我想在 MVVM 中动态绑定(bind)多个按钮。
1.我使用 ItemControl
动态创建按钮2.它没有调用触发点击事件。请帮我解决这个问题。

        <ItemsControl ItemsSource="{Binding ComponentList,Mode=TwoWay}">
                <ItemsControl.ItemTemplate>
                    <DataTemplate>
                        <StackPanel Orientation="Horizontal">
                            <Button Tag="{Binding WorkFlowCompId}">
                                <Button.Content>
                                    <TextBlock Text="{Binding ComponentName,Mode=TwoWay}"/>
                                </Button.Content>
                                <i:Interaction.Triggers>
                                    <i:EventTrigger EventName="Click">
                                        <i:InvokeCommandAction Command="{Binding ComponentSelected}" 
CommandParameter="{Binding WorkFlowCompId,Mode=TwoWay}" >
                                        </i:InvokeCommandAction>
                                    </i:EventTrigger>
                                </i:Interaction.Triggers>
                            </Button>
                        </StackPanel>
                    </DataTemplate>
                </ItemsControl.ItemTemplate>
            </ItemsControl>

Answer 1

您的问题是该命令正在从其模板中获取上下文，并且无法访问 ViewModel 的根目录。将此类添加到您的解决方案中:

public class DataContextProxy : FrameworkElement
    {
        public DataContextProxy()
        {
            this.Loaded += new RoutedEventHandler(DataContextProxyLoaded);
        }

        void DataContextProxyLoaded(object sender, RoutedEventArgs e)
        {
            Binding binding = new Binding();
            if (!String.IsNullOrEmpty(BindingPropertyName))
            {
                binding.Path = new PropertyPath(BindingPropertyName);
            }
            binding.Source = this.DataContext;
            binding.Mode = BindingMode;
            this.SetBinding(DataContextProxy.DataSourceProperty, binding);
        }

        public Object DataSource
        {
            get { return (Object)GetValue(DataSourceProperty); }
            set { SetValue(DataSourceProperty, value); }
        }

        public static readonly DependencyProperty DataSourceProperty =
            DependencyProperty.Register("DataSource", typeof(Object), typeof(DataContextProxy), null);


        public string BindingPropertyName { get; set; }

        public BindingMode BindingMode { get; set; }

    }

然后像这样在 XAML 中使用它:

 <UserControl.Resources>
            <library:DataContextProxy x:Key="DataContextProxy"/>
    </UserControl.Resources>

然后在你的命令绑定(bind)中:

<Button Tag="{Binding WorkFlowCompId}">
                                <Button.Content>
                                    <TextBlock Text="{Binding ComponentName,Mode=TwoWay}"/>
                                </Button.Content>
                                <i:Interaction.Triggers>
                                    <i:EventTrigger EventName="Click">
                                        <i:InvokeCommandAction Command="{Binding DataSource.ComponentSelected, Source={StaticResource DataContextProxy}" 
CommandParameter="{Binding WorkFlowCompId,Mode=TwoWay}" >
                                        </i:InvokeCommandAction>
                                    </i:EventTrigger>
                                </i:Interaction.Triggers>
                            </Button>