Create a folder in document library using Sharepoint event receiver

Question

I am using the following code to create a folder inside my document library. The event get triggered and executed till the last line of my code without any issues. However the folder is not getting created or listed in my document library.

public override void ItemAdded(SPItemEventProperties properties)
{
    base.ItemAdded(properties);        

    string strDashListRoot = "http://win-hmpjltdbh5q:37642";
    using (SPSite site = new SPSite(strDashListRoot))
    {
        using (SPWeb web = site.OpenWeb())
        {
            web.AllowUnsafeUpdates = true;                    

            SPList spl = web.Lists["client_documents"];
            spl.Items.Add("", SPFileSystemObjectType.Folder, "Helllworld");
            spl.Update();
            web.AllowUnsafeUpdates = false;
        }
    }           
}

Answer 1

You need

var i = spl.Items.Add("", SPFileSystemObjectType.Folder, "Helllworld");
i.Update(); 

instead of

spl.Items.Add("", SPFileSystemObjectType.Folder, "Helllworld");
spl.Update();

(assuming your Add call is fine - it looks OK to me)

(Also, are you sure you need the AllowUnsafeUpdates handling? I wouldn't have expected it to be necessary when you're in an ItemAdded handler.)

Answer 2

I developed the following code based on Rawling's answer:

private static void CreateFolder(SPWeb web, SPList spList, SPListItem currentItem, string folderName)
{
    if (currentItem.FileSystemObjectType != SPFileSystemObjectType.Folder)
    {
        string itemUrl = web.Url + "/" + currentItem.Url.Substring(0, currentItem.Url.LastIndexOf('/'));

        var folder = spList.Items.Add(itemUrl, SPFileSystemObjectType.Folder, folderName);
        string folderUrl = itemUrl + "/" + folder.Name;

        if (!FolderExists(folderUrl, web))
        {
            try
            {
                folder.Update();
            }
            catch (Exception)
            {
                throw;
            }
        }
    }
}


public static bool FolderExists(string url, SPWeb web)
{
    if (url.Equals(string.Empty))
    {
        return false;
    }

    try
    {
        return web.GetFolder(url).Exists;
    }
    catch (ArgumentException)
    {
        throw;
    }
    catch (Exception)
    {
        throw;
    }
}