public void DeleteItemPropertyMapping(Guid id)
 {
     foreach (FolderSetting fs in this)
     {
         ItemPropertyMapping itemPropertyMapping = fs.ItemPropertyMappings.SingleOrDefault(t => t.ID.Equals(id));
         if (itemPropertyMapping != null)
         {
             fs.ItemPropertyMappings.Remove(itemPropertyMapping);
         }
     }
 }
        public ItemPropertyMapping GetItemPropertyMapping(Guid id, out FolderSetting folderSetting)
        {
            foreach (FolderSetting fs in this)
            {
                ItemPropertyMapping itemPropertyMapping = fs.ItemPropertyMappings.SingleOrDefault(t => t.ID.Equals(id));
                if (itemPropertyMapping != null)
                {
                    folderSetting = fs;
                    return(itemPropertyMapping);
                }
            }

            folderSetting = null;
            return(null);
        }