在 wpf-treeview 中查找父项

Question

我希望my previous question 的答案能帮助我解决这个问题，但没有。最初的情况几乎相同：

<TreeView ItemsSource="{Binding Groups}" Name="tvGroups" AllowDrop="True">
          <TreeView.ItemTemplate>
                    <HierarchicalDataTemplate ItemsSource="{Binding Participants}">
                          <StackPanel Orientation="Horizontal" Drop="tvDrop" Tag="{Binding .}">
                               <TextBlock Text="{Binding Name}" />
                               <Button Tag="{Binding .}" Click="Button_Click_2">
                                    <Image Source="Resources/cross.png" />
                                </Button>
                          </StackPanel>
                          <HierarchicalDataTemplate.ItemTemplate>
                              <DataTemplate>
                                  <StackPanel Orientation="Horizontal" >
                                       <TextBlock Text="{Binding Alias}" />
                                       <Button Tag="{Binding .}" Name="btnDeleteParticipants" Click="btnParticipants_Click" >
                                            <Image Source="Resources/cross.png" />
                                       </Button>
                                  </StackPanel>
                              </DataTemplate>
                          </HierarchicalDataTemplate.ItemTemplate>
                    </HierarchicalDataTemplate>
          </TreeView.ItemTemplate>
</TreeView>

---

 private void btnParticipants_Click(object sender, RoutedEventArgs e)//Probanten aus Gruppe entfernen
        {
            Participant p = ((sender as Button).Tag as Participant);
            if (p == null) return;
            //TODO: Raus bekommen in welcher Gruppe ich löschen will

        }

我想通过单击按钮 (btnDeleteParticipants) 从 Group 中删除 Participant p。我试过这样的：

Control c = sender as Control;
while (!(c is TreeViewItem))
     c = (c.Parent) as Control;

但这不起作用（不要问为什么，我不确定）。我可以通过检查它是否包含Participant（绑定到btnDeleteParticipants.Tag）来找到Group，但这将不允许参与者加入超过1个组。 那么，任何想法如何获得正确的Group？

编辑：

Groups = new ObservableCollection<Group>();
Participants = new ObservableCollection<Participant>();

Answer 1

组和参与者是 ObservableCollection 对象吗？

试试这个：

static TObject FindVisualParent<TObject>(UIElement child) where TObject : UIElement
{
  if (child == null)
  {
    return null;
  }

  UIElement parent = VisualTreeHelper.GetParent(child) as UIElement;

  while (parent != null)
  {
    TObject found = parent as TObject;
    if (found != null)
    {
      return found;
    }
    else
    {
      parent = VisualTreeHelper.GetParent(parent) as UIElement;
    }
  }

  return null;
}

另外，尝试使用 DataContext 获取参与者并将 Tag 设置为 TemplatedParent。

<Button Tag="{Binding RelativeSource={RelativeSource TemplatedParent}}" />

然后点击

private void btnParticipants_Click(object sender, RoutedEventArgs e)
{
  var button = sender as Button;
  var p = button.DataContext as Participant;
  if (p == null) return;

  var t= FindVisualParent<TreeViewItem>(button); // get the Participants TreeViewItem
  if (t == null) return;
  var groupTreeItem = FindVisualParent<TreeViewItem>(t);  // get the groups TreeViewItem
  if (groupTreeItem == null) return;
  var group = groupTreeItem.DataContext as Group;
  group.Participants.Remove(p);
}