WPF TreeView横向排列

WPF 第三级横向排列效果，左侧使用WrapPanel，右侧使用StackPanel,效果见下图：

代码如下：

Mainwindow的xaml如下:

<Window x:Class="WPFDemos.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WPFDemos"
        mc:Ignorable="d"
        x:Name="widnow"
        WindowStartupLocation="CenterScreen"
        UseLayoutRounding="True"
        Background="LightBlue"
        FontSize="16"
        Title="title" Height="500" Width="1000">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition/>
            <ColumnDefinition/>
        </Grid.ColumnDefinitions>
        <TreeView Grid.Column="0" Margin="5" Width="300" ItemsSource="{Binding Items,ElementName=widnow}">
            <TreeView.ItemTemplate>
                <HierarchicalDataTemplate ItemsSource="{Binding Children}">
                    <HierarchicalDataTemplate.ItemContainerStyle>
                        <Style TargetType="TreeViewItem">
                            <Setter Property="ItemsPanel">
                                <Setter.Value>
                                    <ItemsPanelTemplate>
                                        <WrapPanel Width="300"/>
                                    </ItemsPanelTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </HierarchicalDataTemplate.ItemContainerStyle>
                    <TextBlock Text="{Binding DisplayText}"/>
                    <HierarchicalDataTemplate.ItemTemplate>
                        <HierarchicalDataTemplate ItemsSource="{Binding Children}">
                            <TextBlock Text="{Binding DisplayText}"/>
                        </HierarchicalDataTemplate>
                    </HierarchicalDataTemplate.ItemTemplate>
                </HierarchicalDataTemplate>
            </TreeView.ItemTemplate>
        </TreeView>
        <TreeView Grid.Column="1" Margin="5" Width="300" ItemsSource="{Binding Items,ElementName=widnow}">
            <TreeView.ItemTemplate>
                <HierarchicalDataTemplate ItemsSource="{Binding Children}">
                    <HierarchicalDataTemplate.ItemContainerStyle>
                        <Style TargetType="TreeViewItem">
                            <Setter Property="ItemsPanel">
                                <Setter.Value>
                                    <ItemsPanelTemplate>
                                        <StackPanel Orientation="Horizontal"/>
                                    </ItemsPanelTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </HierarchicalDataTemplate.ItemContainerStyle>
                    <TextBlock Text="{Binding DisplayText}"/>
                    <HierarchicalDataTemplate.ItemTemplate>
                        <HierarchicalDataTemplate ItemsSource="{Binding Children}">
                            <TextBlock Text="{Binding DisplayText}"/>
                        </HierarchicalDataTemplate>
                    </HierarchicalDataTemplate.ItemTemplate>
                </HierarchicalDataTemplate>
            </TreeView.ItemTemplate>
        </TreeView>
    </Grid>
</Window>

MainWindow的后台代码如下：

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Globalization;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Media;
namespace WPFDemos
{
    public partial class MainWindow : Window, INotifyPropertyChanged
    {
        private ObservableCollection<ItemViewModel> _items = new ObservableCollection<ItemViewModel>();
        public ObservableCollection<ItemViewModel> Items
        {
            get { return _items; }
            set
            {
                _items = value;
                OnPropertyChanged(nameof(Items));
            }
        }

        public MainWindow()
        {
            InitializeComponent();
            Items = new ObservableCollection<ItemViewModel>()
            {
                new ItemViewModel
                {
                    DisplayText="中国人",
                    Children=new ObservableCollection<ItemViewModel>
                    {
                        new ItemViewModel{DisplayText="马云"},
                        new ItemViewModel{DisplayText="马化腾",
                            Children=new ObservableCollection<ItemViewModel>(){
                                new ItemViewModel{ DisplayText="身价：100亿"},
                                new ItemViewModel{ DisplayText="老婆数：100个"},
                                new ItemViewModel{ DisplayText="老婆数：100个"},
                                new ItemViewModel{ DisplayText="老婆数：100个"},
                                new ItemViewModel{ DisplayText="老婆数：100个"},
                            }},
                        new ItemViewModel{
                            DisplayText="WPF UI作者",
                            Children=new ObservableCollection<ItemViewModel>(){
                                new ItemViewModel{ DisplayText="身价：100亿"},
                                new ItemViewModel{ DisplayText="老婆数：100个"},
                                new ItemViewModel{ DisplayText="老婆数：100个"},
                                new ItemViewModel{ DisplayText="老婆数：100个"},
                                new ItemViewModel{ DisplayText="老婆数：100个"},
                            }
                        },
                    }
                },
                new ItemViewModel
                {
                    DisplayText="中国人",
                    Children=new ObservableCollection<ItemViewModel>
                    {
                        new ItemViewModel{DisplayText="马云"},
                        new ItemViewModel{DisplayText="马化腾"},
                        new ItemViewModel{DisplayText="WPF UI作者"},
                    }
                },
                new ItemViewModel
                {
                    DisplayText="歪果人",
                    Children=new ObservableCollection<ItemViewModel>
                    {
                        new ItemViewModel{DisplayText="乔布斯"},
                        new ItemViewModel{DisplayText="巴菲特"},
                    }
                },
            };
        }

        public event PropertyChangedEventHandler PropertyChanged;
        public void OnPropertyChanged(string name)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
        }
    }
    public class ItemViewModel : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;
        public void OnPropertyChanged(string name)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
        }
        public string DisplayText { get; set; }
        public ObservableCollection<ItemViewModel> Children { get; set; } = new ObservableCollection<ItemViewModel>();
    }
    public class TreeItemMarginConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            var left = 0.0;
            UIElement element = value as TreeViewItem;
            while (element != null && element.GetType() != typeof(TreeView))
            {
                element = (UIElement)VisualTreeHelper.GetParent(element);
                if (element is TreeViewItem)
                    left += 18.0;
            }
            return new Thickness(left, 0, 0, 0);
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }
}

全部代码都在上面喽，欢迎指点。