C# 使用Linq递归查询当前节点及所有子节点

    /// <summary>
    /// C#Linq使用递归获取当前节点及所有子节点
    /// </summary>
    public class LinqRecursive
    {
        public IEnumerable<sys_ProductFunctionAll> List { get; set; }
        
        public List<sys_ProductFunctionAll> Get(string parentId)
        {
            return DoRecursive(parentId).ToList();
        }

        private IEnumerable<sys_ProductFunctionAll> DoRecursive(string parentId)
        {            
            return List.Where(e => e.ParentFunctionID == parentId)
                       .SelectMany(e => new[] { e }.Concat(DoRecursive(e.FunctionID)))//递归获取子节点
                       .Union(List.Where(w => w.FunctionID == parentId)).ToList();//添加当前节点
        }
    }

var nodes = new LinqRecursive { List = listAll }.Get(nodeId);