I have a custom list named “Custom”. I have a folder called "2012" in the list. I need to add a subfolder inside "2012" folder.

In this blog you will see how to create a subfolder in the list using SharePoint Object Model.

Code Snippet:

 
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.SharePoint;
using System.Collections;
 
namespace CreateSubfolder
{
    class Program
    {
        static void Main(string[] args)
        {
            using (SPSite site = new SPSite("http://serverName/sites/Vijai/"))
            {
                using (SPWeb web = site.OpenWeb())
                {
                    SPList list = web.Lists.TryGetList("Custom");
                    if (list != null)
                    {
                        foreach (SPListItem item in list.Folders)
                        {
                            if (item.Title == "2012")
                            {
                                SPListItem newItem = list.AddItem(item.Folder.ServerRelativeUrl, SPFileSystemObjectType.Folder);
                                newItem["Title"] = "2012SubFolder1";
                                newItem.Update();
                            }
                        }                       
                    }
                }
            }
        }
    }}


A subfolder named "2012SubFolder1" is created successfully inside "2012" folder in the custom list.