private IEnumerable <INCategory> GetFolders(int?categoryID) { if (categoryID == null) { yield return(new INCategory { CategoryID = 0, Description = PXSiteMap.RootNode.Title }); } foreach (INCategory item in CategoryCache <INCategory> .GetChildren(this, categoryID)) { if (!string.IsNullOrEmpty(item.Description)) { yield return(item); } } }