自定义Treeview用户控件MVVM双击冒泡事件WPF

1 回答

• 2

  您根本不需要在用户控件外部发布双击事件 . 您需要在TreeView.SelectedItem的InputBindings集合中添加一些InputBinding（在此特定情况下为MouseBinding） .

  问题是你不能以正常，明显的方式做到这一点 - 通过 TreeView.ItemContainerStyle 设置 InputBindings ，因为 InputBindings 集合是只读的 . 悲伤，但是真的 .

  好消息是你可以使用附属物来实现这一目标 . 例子：

  查看模型 .
  a）这将在树视图中显示为项目：

  public class Node : ViewModelBase
  {
      public String Text
      {
          get { return text; }
          set
          {
              if (text != value)
              {
                  text = value;
                  OnPropertyChanged("Text");
              }
          }
      }
      private String text;
  
      public ObservableCollection<Node> Nodes { get; set; }
  }
  

  b）这是“主要”视图模型：

  public class ViewModel : ViewModelBase
  {
      public ViewModel()
      {
          this.selectedNodeDoubleClickedCommand = new RelayCommand<Node>(node => 
          {
              Debug.WriteLine(String.Format("{0} clicked!", node.Text));
          });
      }
  
      public ObservableCollection<Node> Nodes { get; set; }
  
      public RelayCommand<Node> SelectedNodeDoubleClickedCommand
      {
          get { return selectedNodeDoubleClickedCommand; }
      }
      private readonly RelayCommand<Node> selectedNodeDoubleClickedCommand;
  }
  

  用户控制代码隐藏 . 基本思路 - 我们在XAML中添加一个附加属性来设置输入绑定，另一个 - 当输入绑定触发时，允许外部世界绑定命令：

  public partial class UserControl1 : UserControl
  {
      public UserControl1()
      {
          InitializeComponent();
      }
  
      public ICommand SelectedItemDoubleClickedCommand
      {
          get { return (ICommand)GetValue(SelectedItemDoubleClickedCommandProperty); }
          set { SetValue(SelectedItemDoubleClickedCommandProperty, value); }
      }
  
      public static readonly DependencyProperty SelectedItemDoubleClickedCommandProperty = DependencyProperty.Register(
          "SelectedItemDoubleClickedCommand", typeof(ICommand), 
          typeof(UserControl1), 
          new UIPropertyMetadata(null));
  
      public static ICommand GetSelectedItemDoubleClickedCommandAttached(DependencyObject obj)
      {
          return (ICommand)obj.GetValue(SelectedItemDoubleClickedCommandAttachedProperty);
      }
  
      public static void SetSelectedItemDoubleClickedCommandAttached(DependencyObject obj, ICommand value)
      {
          obj.SetValue(SelectedItemDoubleClickedCommandAttachedProperty, value);
      }
  
      public static readonly DependencyProperty SelectedItemDoubleClickedCommandAttachedProperty = DependencyProperty.RegisterAttached(
          "SelectedItemDoubleClickedCommandAttached", 
          typeof(ICommand), typeof(UserControl1), 
          new UIPropertyMetadata(null, SelectedItemDoubleClickedCommandAttachedChanged));
  
      private static void SelectedItemDoubleClickedCommandAttachedChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
      {
          var item = d as TreeViewItem;
          if (item != null)
          {
              if (e.NewValue != null)
              {
                  var binding = new MouseBinding((ICommand)e.NewValue, new MouseGesture(MouseAction.LeftDoubleClick));
  
                  BindingOperations.SetBinding(binding, InputBinding.CommandParameterProperty, new Binding("SelectedItem")
                  {
                      RelativeSource = new RelativeSource(RelativeSourceMode.FindAncestor, typeof(TreeView), 1)
                  });
  
                  item.InputBindings.Add(binding);
              }
          }
      }
  }
  

  用户控制XAML：

  <Grid>
      <TreeView ItemsSource="{Binding Nodes}">
          <TreeView.Resources>
              <HierarchicalDataTemplate ItemsSource="{Binding Nodes}" DataType="{x:Type local:Node}">
                  <TextBlock Text="{Binding Text}"/>
              </HierarchicalDataTemplate>
          </TreeView.Resources>
          <TreeView.ItemContainerStyle>
              <Style TargetType="{x:Type TreeViewItem}">
                  <Setter Property="local:UserControl1.SelectedItemDoubleClickedCommandAttached" 
                          Value="{Binding SelectedItemDoubleClickedCommand, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type UserControl}}}" />
              </Style>
          </TreeView.ItemContainerStyle>
  
      </TreeView>
  </Grid>
  

  主窗口XAML：

  <Window x:Class="WpfApplication2.MainWindow"
          xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
          xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
          xmlns:local="clr-namespace:WpfApplication2"
          Title="MainWindow" Height="350" Width="525">
      <Grid>
          <local:UserControl1 SelectedItemDoubleClickedCommand="{Binding SelectedNodeDoubleClickedCommand}"/>
      </Grid>
  </Window>
  

  主窗口代码隐藏：

  public partial class MainWindow : Window
  {
      public MainWindow()
      {
          InitializeComponent();
          DataContext = new ViewModel
          {
              Nodes = new ObservableCollection<Node>
              {
                  new Node
                  {
                      Text = "Parent 1",
                      Nodes = new ObservableCollection<Node>
                      {
                          new Node { Text = "Child 1.1"},
                          new Node { Text = "Child 1.2"},
                      }
                  },
                  new Node
                  {
                      Text = "Parent 2",
                      Nodes = new ObservableCollection<Node>
                      {
                          new Node { Text = "Child 2.1"},
                          new Node { Text = "Child 2.2"},
                      }
                  },
              }
          };
      }
  }
  

  回复于 2024-05-03T13:39:40+08:00