MainPage.xaml.cs

using System.Xml;
using System.Collections.ObjectModel;
using Microsoft.Maui.Controls;

namespace SuDatabase
{
    public partial class MainPage : ContentPage
    {
        public ObservableCollection<DatabaseObject> Items { get; set; } = new();
        private MainPage _mainPageInstance;

        public MainPage()
        {
            InitializeComponent();
            _mainPageInstance = this;
            LoadDatabaseStructure();
            BuildTreeView();
        }

        private void LoadDatabaseStructure()
        {
            try
            {
                // 加载XML文档
                var assembly = typeof(MainPage).Assembly;
                using var stream = assembly.GetManifestResourceStream("SuDatabase.Database.xml");

                if (stream == null)
                {
                    DisplayAlert("错误", "无法找到Database.xml资源", "确定");
                    return;
                }

                var doc = new XmlDocument();
                doc.Load(stream);

                // 解析对象类型定义
                var objectTypes = new Dictionary<string, DatabaseObjectType>();
                var typeNodes = doc.SelectNodes("//DatabaseObjectTypes/DatabaseObjectType");
                if (typeNodes != null)
                {
                    foreach (XmlNode typeNode in typeNodes)
                    {
                        var name = typeNode.Attributes?["Name"]?.Value;
                        if (name != null)
                        {
                            objectTypes[name] = new DatabaseObjectType
                            {
                                Name = name,
                                IconName = typeNode.Attributes?["IconName"]?.Value ?? "",
                                DefaultInstanceName = typeNode.Attributes?["DefaultInstanceName"]?.Value ?? ""
                            };
                        }
                    }
                }

                // 解析数据库对象
                var rootNodes = doc.SelectNodes("//DatabaseObjects/*");
                if (rootNodes != null)
                {
                    ParseNodes(rootNodes, null, objectTypes);
                }
            }
            catch (Exception ex)
            {
                DisplayAlert("错误", $"加载数据库时出错: {ex.Message}", "确定");
            }
        }

        private void ParseNodes(XmlNodeList nodes, DatabaseObject parent, Dictionary<string, DatabaseObjectType> objectTypes)
        {
            foreach (XmlNode node in nodes)
            {
                var name = node.Attributes?["Name"]?.Value ?? "未命名";
                var guid = node.Attributes?["Guid"]?.Value ?? "";
                var typeName = node.Name;

                var dbObject = new DatabaseObject(_mainPageInstance)
                {
                    Name = name,
                    Guid = guid,
                    Type = typeName,
                    Parent = parent
                };

                // 设置对象类型信息
                if (objectTypes.TryGetValue(typeName, out var objectType))
                {
                    dbObject.ObjectType = objectType;
                }

                // 添加到集合
                Items.Add(dbObject);

                // 递归处理子节点
                if (node.HasChildNodes)
                {
                    ParseNodes(node.ChildNodes, dbObject, objectTypes);
                }
            }
        }

        private void BuildTreeView()
        {
            // 清空现有内容
            TreeViewContainer.Children.Clear();

            // 添加根节点
            var rootItems = Items.Where(i => i.Parent == null).ToList();
            foreach (var item in rootItems)
            {
                AddTreeViewItem(item, 0, TreeViewContainer);
            }
        }

        private void AddTreeViewItem(DatabaseObject item, int indentLevel, Layout container)
        {
            // 创建主容器
            var itemStackLayout = new VerticalStackLayout();

            // 创建显示当前节点的行
            var rowLayout = new HorizontalStackLayout
            {
                Spacing = 5,
                Padding = new Thickness(5 + (indentLevel * 15), 2, 5, 2),
                BackgroundColor = Colors.Transparent
            };

            // 添加展开/折叠图标占位符（保持对齐）
            var spacer = new BoxView
            {
                WidthRequest = 12,
                HeightRequest = 12,
                Color = Colors.Transparent,
                IsVisible = item.HasChildren
            };

            // 添加节点图标
            Image nodeIcon = new Image
            {
                Source = GetIconForType(item.Type),
                WidthRequest = 16,
                HeightRequest = 16
            };

            // 添加节点名称
            Label nameLabel = new Label
            {
                Text = item.Name,
                VerticalOptions = LayoutOptions.Center,
                FontSize = 14
            };

            rowLayout.Children.Add(spacer);
            rowLayout.Children.Add(nodeIcon);
            rowLayout.Children.Add(nameLabel);

            // 创建子节点容器（初始为空）
            var childrenContainer = new VerticalStackLayout
            {
                IsVisible = item.IsExpanded
            };

            // 添加到主容器
            itemStackLayout.Children.Add(rowLayout);
            itemStackLayout.Children.Add(childrenContainer);

            // 添加双击手势识别器
            var doubleTapGesture = new TapGestureRecognizer
            {
                NumberOfTapsRequired = 2
            };

            doubleTapGesture.Tapped += async (s, e) =>
            {
                // 切换展开状态
                item.IsExpanded = !item.IsExpanded;

                // 显示/隐藏子节点容器
                childrenContainer.IsVisible = item.IsExpanded;

                // 如果是展开操作且子容器为空，则动态加载子节点
                if (item.IsExpanded && childrenContainer.Children.Count == 0)
                {
                    var childItems = Items.Where(i => i.Parent == item).ToList();
                    foreach (var child in childItems)
                    {
                        AddTreeViewItem(child, indentLevel + 1, childrenContainer);
                    }
                }
            };

            rowLayout.GestureRecognizers.Add(doubleTapGesture);

            // 添加单击查看详情功能
            var tapGesture = new TapGestureRecognizer();
            tapGesture.Tapped += (s, e) => ShowDetails(item);
            rowLayout.GestureRecognizers.Add(tapGesture);

            // 添加到指定容器
            container.Children.Add(itemStackLayout);
        }

        private string GetIconForType(string type)
        {
            return type switch
            {
                "Folder" => "folder.png",
                "EntityTemplate" => "entity.png",
                "MemberComponentTemplate" => "member_component.png",
                "ParameterSet" => "parameter_set.png",
                "Parameter" => "parameter.png",
                _ => "default.png"
            };
        }

        private void ShowDetails(DatabaseObject item)
        {
            // 清空详情面板
            DetailsPanel.Children.Clear();

            // 添加基本信息
            DetailsPanel.Children.Add(new Label { Text = item.Name, FontSize = 20, FontAttributes = FontAttributes.Bold });
            DetailsPanel.Children.Add(new Label { Text = $"类型: {item.Type}" });
            DetailsPanel.Children.Add(new Label { Text = $"GUID: {item.Guid}" });

            // 显示是否有子项
            DetailsPanel.Children.Add(new Label { Text = $"包含子项: {(item.HasChildren ? "是" : "否")}" });
            DetailsPanel.Children.Add(new Label { Text = $"展开状态: {(item.IsExpanded ? "已展开" : "已折叠")}" });

            // 如果有对象类型信息，显示更多详情
            if (item.ObjectType != null)
            {
                DetailsPanel.Children.Add(new Label { Text = $"默认实例名: {item.ObjectType.DefaultInstanceName}" });
                DetailsPanel.Children.Add(new Label { Text = $"图标: {item.ObjectType.IconName}" });
            }
        }
    }

    // 数据模型类
    public class DatabaseObject
    {
        private readonly MainPage _mainPage;

        public DatabaseObject(MainPage mainPage)
        {
            _mainPage = mainPage;
        }

        public string Name { get; set; } = "";
        public string Guid { get; set; } = "";
        public string Type { get; set; } = "";
        public DatabaseObject? Parent { get; set; }
        public DatabaseObjectType? ObjectType { get; set; }

        // 新增属性
        public bool IsExpanded { get; set; }
        public bool HasChildren => _mainPage.Items.Any(i => i.Parent == this);
    }

    public class DatabaseObjectType
    {
        public string Name { get; set; } = "";
        public string IconName { get; set; } = "";
        public string DefaultInstanceName { get; set; } = "";
    }
}