public async Task <IViewComponentResult> InvokeAsync()
        {
            var categories = _courseData.GetCategories();

            var categoriesModel = new List <CategoryViewModel>();

            foreach (var category in categories)
            {
                var countCourses = _courseData.GetCoursesCountOfCategory(category.Id);
                categoriesModel.Add(new CategoryViewModel
                {
                    FullString = $"{category.Name} ({countCourses})",
                    Category   = category.Name
                });
            }
            var model = new CategoriesViewModel()
            {
                Categories = categoriesModel
            };

            return(View(model));
        }