var allCategories = _categoryService.GetAllCategories(showHidden: true);
                foreach (var category in allCategories)
                {
                   
                        model.AvailableCategories.Add(new SelectListItem
                        {
                            Text = category.GetFormattedBreadCrumb(allCategories),
                            Value = category.Id.ToString()
                        });
                    
                }

 IPagedList<Category> GetAllCategories(string categoryName = "",
            int pageIndex = 0, int pageSize = int.MaxValue, bool showHidden = false);