How do I allow users to create folders but not delete folders?

Question

How can I allow users to create folders but not delete folders in SharePoint 2007?

Answer 1

Create a event reciever using the following code and then attach the event reciever to your document libraries.

private bool CanDeleteFolder(SPWeb web)
{
    //  check to see if the user is in the owners group
    SPUser user = web.CurrentUser;

    if (!user.IsSiteAdmin)
    {
        return false;
    }
    else
    {
        //admins can delete folder
        return true;
    }
}

public override void ItemDeleting(SPItemEventProperties properties)
{
    try
    {
        if (properties.AfterProperties["ContentType"].ToString() == "Folder")
        {
            using (SPWeb web = properties.OpenWeb())
            {
                if (!CanDeleteFolder(web))
                {
                    properties.Cancel = true;
                    properties.ErrorMessage = "Cannot add folder at this location. Please select a sub folder";
                    properties.Status = SPEventReceiverStatus.CancelWithError;
                }
            }
        }
    }
    catch { }
}

Answer 2

Or create a custom permission level that does not allow the delete option and apply that permission level to the library for the desired users. They'll be able to add/edit items but not delete. An event receiver seems like overkill for a simple permissions change.

Answer 3

Could use a custom event receiver to trap OnDeleting to see if the current item being deleted is a folder, and Cancel if so, presenting an error message whilst doing so.