WIn_RustTools/RustTools/Editor/ExplorerItemTemplateSelector.cs

using System.Collections.ObjectModel;
using System.ComponentModel;
using Microsoft.UI.Xaml;
using Microsoft.UI.Xaml.Controls;

namespace RustTools.Editor;
public class ExplorerItemTemplateSelector : DataTemplateSelector
{
    public DataTemplate FolderTemplate
    {
        get; set;
    }
    public DataTemplate FileTemplate
    {
        get; set;
    }

    protected override DataTemplate SelectTemplateCore(object item)
    {
        var explorerItem = (ExplorerItem)item;
        return explorerItem.Type == ExplorerItem.ExplorerItemType.Folder ? FolderTemplate : FileTemplate;
    }
}
public class ExplorerItem : INotifyPropertyChanged
{
    public enum ExplorerItemType { Folder, File };
    public event PropertyChangedEventHandler PropertyChanged;
    public string? Name
    {
        get; set;
    }
    public ExplorerItemType Type
    {
        get; set;
    }
    public string? Dir
    {
        get; set;
    }
    private ObservableCollection<ExplorerItem>? m_children;
    public ObservableCollection<ExplorerItem> Children
    {
        get
        {
            m_children ??= new ObservableCollection<ExplorerItem>();
            return m_children;
        }
        set => m_children = value;
    }

    private bool m_isExpanded;
    public bool IsExpanded
    {
        get => m_isExpanded;
        set
        {
            if (m_isExpanded != value)
            {
                m_isExpanded = value;
                NotifyPropertyChanged(nameof(IsExpanded));
            }
        }
    }

    private void NotifyPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }

    public static implicit operator ExplorerItem(bool v)
    {
        throw new NotImplementedException();
    }
}