一、什么是逻辑树
逻辑树就是描述WPF界面元素的实际构成，它是由程序在XAML中所有的UI元素组成。最显著的特点就是由布局控件、或者其他常用的控件组成。
<Window x:Class="WpfRouteEvent.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="350" Width="525"> <Grid> <StackPanel> <TextBox></TextBox> </StackPanel> </Grid></Window>
从上面的代码中可以看出，Window、Grid、StackPanel、TextBox其实就是XAML界面的逻辑树。
二、什么是可视树
可视树是由界面上可见的元素构成的，这些元素主要是由从Visual或者Visual3D类中派生出来的类。
上面代码中的Window、Grid、StackPanel、TextBox它们本身就包含一些由Visual或者Visual3D类派生出的一些可视树的元素来组成的。
三、逻辑树和可视树的遍历
逻辑树遍历使用LogicalTreeHelper类。
可视树遍历使用VisualTreeHelper类。
演示遍历逻辑树和可视树
1、XAML界面左边显示逻辑树，右边显示可视树，代码如下：
<Window x:Class="WpfRouteEvent.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="350" Width="525"> <Grid> <DockPanel>QiNeFT <Button DockPanel.Dock="Top" Click="Button_Click" Content="获取逻辑树和可视树"></Button> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition></ColumnDefinition> <ColumnDefinition></ColumnDefinition> </Grid.ColumnDefinitions> <DockPanel Grid.Column="0"> <TextBlock DockPanel.Dock="Top" Text="逻辑树"></TextBlock> <TreeView Name="tvLogicTree"></TreeView> </DockPanel> <DockPanel Grid.Column="1"> 易采站长站 <TextBlock DockPanel.Dock="Top" Text="可视树"></TextBlock> <TreeView Name="tvVisualTree"></TreeView> </DockPanel> </Grid> </DockPanel> </Grid></Window>
2、添加类，用于遍历整个XAML界面的逻辑树和可视树
using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Windows;using System.Windows.Controls;using System.Windows.Media;namespace WpfRouteEvent{ public class WpfTreeHelper { static string GetTypeDescription(object obj) { return obj.GetType().FullName; } /// <summary> /// 获取逻辑树 /// </summary> /// <param name="obj"></param> /// <returns></returns> public static TreeViewItem GetLogicTree(DependencyObject obj) { if (obj == null) { return null; } //创建逻辑树的节点 TreeViewItem treeItem = new TreeViewItem {Header=GetTypeDescription(obj),IsExpanded=true }; //循环遍历，获取逻辑树的所有子节点 foreach (var child in LogicalTreeHelper.GetChildren(obj)) { //递归调用 var item = GetLogicTree(child as DependencyObject); if (item != null) { treeItem.Items.Add(item); } } return treeItem; } /// <summary> /// 获取可视树 /// </summary> /// <param name="obj"></param> /// <returns></returns> public static TreeViewItem GetVisualTree(DependencyObject obj) { if (obj == null) { return null; } TreeViewItem treeItem = new TreeViewItem { Header=GetTypeDescription(obj),IsExpanded=true}; for (int i = 0; i < VisualTreeHelper.GetChildrenCount(obj); i++) { var child = VisualTreeHelper.GetChild(obj, i); var item = GetVisualTree(child); if (item != null) { treeItem.Items.Add(item); } } return treeItem; } }}3、在按钮的点击事件中将获取的逻辑树和可视树添加到XAML界面中
using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Windows;using System.Windows.Controls;using System.Windows.Data;using System.Windows.Documents;using System.Windows.Input;using System.Windows.Media;using System.Windows.Media.Imaging;using System.Windows.Navigation;using System.Windows.Shapes;namespace WpfRouteEvent{ /// <summary> /// MainWindow.xaml 的交互逻辑 /// </summary> public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); } private void Button_Click(object sender, RoutedEventArgs e) { this.tvLogicTree.Items.Add(WpfTreeHelper.GetLogicTree(this)); this.tvVisualTree.Items.Add(WpfTreeHelper.GetVisualTree(this)); } }}4、点击按钮，界面运行效果
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