WPF TreeView中重复的孩子

Question

自己解决了。这是我初始化Settings集合的方式。将其注册为DependencyProperty时指定默认值会导致所有设置引用相同的集合对象。向类别添加构造函数并显式初始化设置可解决问题。

---

类别类别指定名称和Settings对象的集合。

using System.Collections.ObjectModel; 
using System.Windows; 

namespace CasEdit 
{ 
    public class Categories : ObservableCollection<Category> { } 

    public class Category : DependencyObject 
    { 
    public string Caption 
    { 
     get { return (string)GetValue(CategoryProperty); } 
     set { SetValue(CategoryProperty, value); } 
    } 
    public static readonly DependencyProperty CategoryProperty = 
     DependencyProperty.Register("Caption", typeof(string), typeof(Category), 
     new UIPropertyMetadata("Category name not set")); 
    public Settings Settings 
    { 
     get { return (Settings)GetValue(SettingsProperty); } 
    } 
    public static readonly DependencyProperty SettingsProperty = 
     DependencyProperty.Register("Settings", typeof(Settings), typeof(Category), 
     new UIPropertyMetadata(new Settings())); 
    } 
} 

以下XAML定义了模板，UI和一些测试数据。

<Window x:Class="CasEdit.MainWindow" 
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
     xmlns:CasEdit="clr-namespace:CasEdit" 
     Title="MainWindow" Height="350" Width="525" > 
    <Window.Resources> 
    <HierarchicalDataTemplate DataType="{x:Type CasEdit:Category}" ItemsSource="{Binding Settings}"> 
     <StackPanel Orientation="Horizontal"> 
     <TextBlock Text="{Binding Caption}" /> 
     <Button Content="Gratuitous button" Margin="3" Click="Button_Click"/> 
     </StackPanel> 
    </HierarchicalDataTemplate> 
    <DataTemplate DataType="{x:Type CasEdit:Setting}" > 
     <StackPanel Orientation="Horizontal"> 
     <TextBlock Text="{Binding Caption}" Margin="3" /> 
     <TextBlock Text="{Binding Template}" Margin="3" /> 
     <TextBox Text="{Binding Editor}" Margin="3" /> 
     <TextBlock Text="{Binding CasDevice}" Margin="3" /> 
     </StackPanel> 
    </DataTemplate> 
    <CasEdit:Categories x:Key="cats"> 
     <CasEdit:Category Caption="1st category"> 
     <CasEdit:Category.Settings> 
      <CasEdit:Setting Caption="Setting 1-1" /> 
      <CasEdit:Setting Caption="Setting 1-2" /> 
     </CasEdit:Category.Settings> 
     </CasEdit:Category> 
     <CasEdit:Category Caption="2nd category" > 
     <CasEdit:Category.Settings> 
      <CasEdit:Setting Caption="Setting 2-1" /> 
     </CasEdit:Category.Settings>   
     </CasEdit:Category> 
     <CasEdit:Category Caption="3rd category" > 
     <CasEdit:Category.Settings> 
      <CasEdit:Setting Caption="Setting 3-1" /> 
     </CasEdit:Category.Settings>   
     </CasEdit:Category> 
    </CasEdit:Categories> 
    </Window.Resources> 
    <Grid> 
    <TreeView x:Name="tree" ItemsSource="{Binding Source={StaticResource cats}}" /> 
    </Grid> 
</Window> 

你会想到树这样

• 第一类
  • 设置1-1
  • 设置1-2
• 第二类
  • 设置2-1
• 第三类
  • 设置3-1

但我得到的是这种

这是非常混乱。我迷失在哪里，每个类别都显示了所有的设置？

Answer 1

这里的最后一个参数告诉使得它使类别的每个实例有它的初始化指向同一个对象设置属性：

public static readonly DependencyProperty SettingsProperty = 
     DependencyProperty.Register("Settings", typeof(Settings), typeof(Category),  
     new UIPropertyMetadata(new Settings())); 

相反，这样做：

public static readonly DependencyProperty SettingsProperty = 
     DependencyProperty.Register("Settings", typeof(Settings), typeof(Category), 
     new UIPropertyMetadata(null)); 
    public Category() 
    { 
     Settings = new Settings(); 
    }