在Asp.Net Mvc中生成树形结构

public class TreeNode
{
    public int Id { get; set; }
    public string Name { get; set; }
    public int? ParentId { get; set; }
    public List<TreeNode> Children { get; set; }
}

public List<TreeNode> GenerateTree(List<TreeNode> nodes)
{
    var rootNodes = new List<TreeNode>();

    // 将所有节点按照父节点进行分组
    var groupedNodes = nodes.GroupBy(n => n.ParentId);

    // 遍历根节点
    foreach (var rootNode in groupedNodes.FirstOrDefault(g => !g.Key.HasValue))
    {
        BuildTree(rootNode, groupedNodes);
        rootNodes.Add(rootNode);
    }

    return rootNodes;
}

private void BuildTree(TreeNode node, IGrouping<int?, TreeNode>[] groupedNodes)
{
    // 获取当前节点的子节点
    var children = groupedNodes.FirstOrDefault(g => g.Key == node.Id)?.ToList();

    if (children != null)
    {
        // 递归构建子节点的树形结构
        foreach (var child in children)
        {
            BuildTree(child, groupedNodes);
        }

        // 将子节点添加到当前节点的子节点列表中
        node.Children = children;
    }
}

public ActionResult Index()
{
    // 模拟一些节点数据
    var nodes = new List<TreeNode>
    {
        new TreeNode { Id = 1, Name = "Node 1", ParentId = null },
        new TreeNode { Id = 2, Name = "Node 1.1", ParentId = 1 },
        new TreeNode { Id = 3, Name = "Node 1.2", ParentId = 1 },
        new TreeNode { Id = 4, Name = "Node 1.2.1", ParentId = 3 },
        new TreeNode { Id = 5, Name = "Node 2", ParentId = null },
        new TreeNode { Id = 6, Name = "Node 2.1", ParentId = 5 },
        new TreeNode { Id = 7, Name = "Node 2.2", ParentId = 5 },
        new TreeNode { Id = 8, Name = "Node 2.2.1", ParentId = 7 }
    };

    var tree = GenerateTree(nodes);

    return View(tree);
}

@model List<TreeNode>

<ul>
    @foreach (var node in Model)
    {
        <li>@node.Name</li>
        @RenderChildren(node)
    }
</ul>

@helper RenderChildren(TreeNode node)
{
    if (node.Children != null && node.Children.Any())
    {
        <ul>
            @foreach (var child in node.Children)
            {
                <li>@child.Name</li>
                @RenderChildren(child)
            }
        </ul>
    }
}