从字符串数组递归创建树层次结构

我有一个由“！”分隔的字符串数组。我正在尝试拆分该字符串并在名为 PivotGroup 的自定义类中递归创建树层次结构。例如，我的目标是分解字符串数组

 string[] paths = new string[] {
            "ROOT!ZZZ!AAA!EEE!15712",
            "ROOT!ZZZ!AAA!EEE!15722",
            "ROOT!ZZZ!AAA!EEE!13891"}

进入 PivotGroup 类，如 PivotGroup 包含ChildGroups[]嵌入的数组字符串。

例如：

     PivotGroup pgGroup = new PivotGroup();
     pgGroup.ChildGroups[0] = PivotGroup[]; // Key:Book Level 3 Value: "AAA"

现在，在 Book Level 3 ChildGroups 中，我需要设置 Book Level 4，其值为“EEE”，在“EEE”的 ChildGroups 中，我需要创建另一个 childGroup 数组，在这种情况下，其大小为 3，称为 Book Level 5 并设置另一个15712、15722、13891 之后的每个数据透视组

这是我的 PivotGroup 类和嵌入的类对象：

public class PivotGroup
{
    public PivotGroup() { }

    public PivotGroup(PivotGroupKey groupKey, PivotRow data, PivotGroup[] childGroups, bool leaf, int groupLevel)
    {
        GroupKey = groupKey;
        Data = data;
        ChildGroups = childGroups;
        Leaf = leaf;
        GroupLevel = groupLevel;
    }

    public PivotGroupKey GroupKey { get; private set; }
    public PivotRow Data { get; private set; }
    public PivotGroup[] ChildGroups { get; set; }
    public bool Leaf { get; private set; }
    public int GroupLevel { get; private set; }

    public override string ToString()
    {
        return GroupKey + ", GroupLevel: " + GroupLevel + ", Children: " +
            ChildGroups.Length + (Leaf ? " (Leaf)" : "");
    }
}

public class PivotGroupKey
{
    public PivotGroupKey()
    {
    }

    public PivotGroupKey(string keyGroup, string keyValue)
    {
        if(keyGroup != null)
            KeyGroup = string.Intern(keyGroup);

        if (keyValue != null)
            KeyValue = string.Intern(keyValue);
    }

    public string KeyGroup { get; private set; }
    public string KeyValue { get; private set; }

    public override string ToString()
    {
        return KeyGroup + ": " + KeyValue;
    }
}

public class PivotRow
{
    public PivotRow()
    {
    }

    public PivotRow(string key, params object[] data) : this(key, true, data) { }

    public PivotRow(string key, bool entitled, params object[] data)
    {
        Data = data;
        Key = null;
        Entitled = entitled;
    }

    public object[] Data { get; private set; }
    public bool Entitled { get; private set; }
    public string Key { get { return null; } set { } }
}

我试过的主程序：

public class BookLevels 
{
    public string Root { get; set; }
    public string BookLevel2 { get; set; }
    public string BookLevel3 { get; set; }
    public string BookLevel4 { get; set; }
    public string BookLevel5 { get; set; }
}

class Program
{
    static void BuildTree(string[] paths)
    {
        var BookPaths = paths.Select(x => x.Split('!'))
            .Select(x => new BookLevels
            {
                Root = x[0],
                BookLevel2 = x[1],
                BookLevel3 = x[2],
                BookLevel4 = x[3],
                BookLevel5 = x[4]
            }).GroupBy(z => new { z.BookLevel3, z.BookLevel4 }).ToArray();


        var BookLevel3Cnt = BookPaths.Select(q => q.Key.BookLevel3).Count();

        PivotGroup root = new PivotGroup(
            new PivotGroupKey("Total", ""),
            new PivotRow(null, new string[8]),
            new PivotGroup[BookLevel3Cnt], false, 0);

        foreach (var booklevel3 in BookPaths)
        {
            AddChildren(root, booklevel3);
        }
    }

    private static void AddChildren(PivotGroup root, IGrouping<object, BookLevels> booklevel, int index = 0)
    {
        root.ChildGroups[index] = new PivotGroup(
        new PivotGroupKey("Book Level " + (index + 3).ToString(), booklevel.Key.ToString()),
        new PivotRow(null, new string[8]),
        AddChildren(root, booklevel[index], index + 1), false, 0);
    }

    static void Main(string[] args)
    {
        string[] paths = new string[] {
            "ROOT!ZZZ!AAA!EEE!15712",
            "ROOT!ZZZ!AAA!EEE!15722",
            "ROOT!ZZZ!AAA!EEE!13891",
            "ROOT!ZZZ!AAA!DDD!15712",
            "ROOT!ZZZ!AAA!DDD!15722",
            "ROOT!ZZZ!AAA!DDD!13891",
            "ROOT!ZZZ!BBB!DDD!15812",
            "ROOT!ZZZ!BBB!DDD!15822",
            "ROOT!ZZZ!BBB!DDD!13891",
        };

        BuildTree(paths);
        Console.WriteLine();
        Console.ReadLine();
    }

我认为我的问题可能是我创建拆分字符串的 Linq 语句的方式，因为我不确定如何递归地处理它。