Hierarchy folder creation using c#

using System;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.IO;

public class FolderData
{
    public Guid ID { get; set; }
    public Guid? ParentID { get; set; }
    public string AccountParentName { get; set; }
    public string Name { get; set; }
}

class Program
{
    static void Main()
    {
        var folderDataList = GetFolderDataFromDatabase();
        var folderTree = BuildFolderTree(folderDataList);
        CreateFolders(folderTree, @"C:\BaseFolderPath");
    }

    private static List GetFolderDataFromDatabase()
    {
        var folderDataList = new List();
        string connectionString = "Enter your_connection_string";
        string query = "SELECT ID, ParentID, AccountParentName, Name FROM YourTable";

        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            SqlCommand command = new SqlCommand(query, connection);
            connection.Open();

            using (SqlDataReader reader = command.ExecuteReader())
            {
                while (reader.Read())
                {
                    var folderData = new FolderData
                    {
                        ID = reader.GetGuid(0),
                        ParentID = reader.IsDBNull(1) ? (Guid?)null : reader.GetGuid(1),
                        AccountParentName = reader.GetString(2),
                        Name = reader.GetString(3)
                    };
                    folderDataList.Add(folderData);
                }
            }
        }

        return folderDataList;
    }

    private static Dictionary> BuildFolderTree(List folderDataList)
    {
        var folderTree = new Dictionary>();

        foreach (var folderData in folderDataList)
        {
            if (folderData.ParentID.HasValue)
            {
                if (!folderTree.ContainsKey(folderData.ParentID.Value))
                {
                    folderTree[folderData.ParentID.Value] = new List();
                }
                folderTree[folderData.ParentID.Value].Add(folderData);
            }
            else
            {
                if (!folderTree.ContainsKey(Guid.Empty))
                {
                    folderTree[Guid.Empty] = new List();
                }
                folderTree[Guid.Empty].Add(folderData);
            }
        }

        return folderTree;
    }

    private static void CreateFolders(Dictionary> folderTree, string baseFolderPath)
    {
        if (!Directory.Exists(baseFolderPath))
        {
            Directory.CreateDirectory(baseFolderPath);
        }

        CreateSubFolders(folderTree, Guid.Empty, baseFolderPath);
    }

    private static void CreateSubFolders(Dictionary> folderTree, Guid parentId, string parentPath)
    {
        if (!folderTree.ContainsKey(parentId)) return;

        foreach (var folderData in folderTree[parentId])
        {
            string currentFolderPath = Path.Combine(parentPath, folderData.Name);

            if (!Directory.Exists(currentFolderPath))
            {
                Directory.CreateDirectory(currentFolderPath);
            }

            // Save files in the respective folder
            File.WriteAllText(Path.Combine(currentFolderPath, "example.txt"), "This is an example file content");

            CreateSubFolders(folderTree, folderData.ID, currentFolderPath);
        }
    }
}

Please try this.....