C# Avalonia 19- DataBinding- DirectoryTreeView

DirectoryTreeView.axaml代码

<Window xmlns="https://github.com/avaloniaui"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"Height="300" Width="300"x:Class="AvaloniaUI.DirectoryTreeView"Title="DirectoryTreeView"><Grid Margin="3"><TreeView Name="treeFileSystem"/></Grid>
</Window>

DirectoryTreeView.axaml.cs代码

using Avalonia;
using Avalonia.Controls;
using Avalonia.Interactivity;
using System;
using System.Collections.Generic;
using System.IO;namespace AvaloniaUI;public partial class DirectoryTreeView : Window
{private static readonly object Placeholder = new();public DirectoryTreeView(){InitializeComponent();BuildTree();}private void BuildTree(){treeFileSystem.Items.Clear();foreach (var drive in DriveInfo.GetDrives()){if (!drive.IsReady)continue;var item = CreateItem(drive.Name, drive);AddPlaceholder(item);treeFileSystem.Items.Add(item);}}private TreeViewItem CreateItem(string header, object tag){var item = new TreeViewItem{Header = header,Tag = tag};item.Expanded += ItemExpanded;return item;}private void ItemExpanded(object? sender, RoutedEventArgs e){if (sender is not TreeViewItem item)return;// 只在第一次展开（且存在占位符）时加载if (item.Items.Count != 1 || !ReferenceEquals(item.Items[0], Placeholder))return;item.Items.Clear();var dir = GetDirectoryInfo(item.Tag);if (dir is null)return;foreach (var subDir in SafeEnumerateDirectories(dir)){var child = CreateItem(subDir.Name, subDir);// 只有确实还有子目录，才显示展开箭头（放占位符）if (HasSubdirectories(subDir))AddPlaceholder(child);item.Items.Add(child);}}private static DirectoryInfo? GetDirectoryInfo(object? tag){if (tag is DriveInfo drive)return drive.RootDirectory;if (tag is DirectoryInfo dir)return dir;return null;}private static void AddPlaceholder(TreeViewItem item){item.Items.Add(Placeholder);}private static IEnumerable<DirectoryInfo> SafeEnumerateDirectories(DirectoryInfo dir){IEnumerator<DirectoryInfo>? enumerator = null;try{enumerator = dir.EnumerateDirectories().GetEnumerator();}catch{yield break;}using (enumerator as IDisposable){while (true){DirectoryInfo current;try{if (!enumerator.MoveNext())break;current = enumerator.Current;}catch{// 某个子目录读不了：跳过，不影响整层continue;}yield return current;}}}private static bool HasSubdirectories(DirectoryInfo dir){try{using var e = dir.EnumerateDirectories().GetEnumerator();return e.MoveNext();}catch{return false;}}
}

运行效果