Frederik Vig – ASP.NET developer

using System.Linq;
using EPiServer.Core;
using EPiServer.DataAbstraction;
 
namespace EPiCode.Extensions
{
    public static class CategoryExtensions
    {
        public static CategoryCollection GetActiveSubCategories(this CategoryList allActiveCategoryIds, string parentCategoryName)
        {
            return allActiveCategoryIds.GetActiveSubCategories(Category.Find(parentCategoryName));
        }
 
        public static CategoryCollection GetActiveSubCategories(this CategoryList allActiveCategoryIds, int parentCategoryId)
        {
            return allActiveCategoryIds.GetActiveSubCategories(Category.Find(parentCategoryId));
        }
 
        public static CategoryCollection GetActiveSubCategories(this CategoryList allActiveCategoryIds, Category parentCategory)
        {
            if (allActiveCategoryIds == null || allActiveCategoryIds.Count < 1 || parentCategory == null)
            {
                return null;
            }
 
            CategoryCollection subCategories = Category.Find(parentCategory.ID).Categories;
 
            var activeCategories = new CategoryCollection();
 
            for (int i = 0; i < allActiveCategoryIds.Count; i++)
            {
                Category category = Category.Find(allActiveCategoryIds.ElementAt(i));
 
                foreach (Category subCategory in subCategories)
                {
                    if (subCategory.ID == category.ID)
                    {
                        activeCategories.Add(category);
                    }
                }
            }
 
            return activeCategories;
        }
    }
}

CategoryCollection activeSubCategories = CurrentPage.Category.GetActiveSubCategories("news");