Engage.Dnn.Publish.Category.GetCategoriesHierarchy C# (CSharp) Method

        public static DataTable GetCategoriesHierarchy(int portalId)
        {
            return DataProvider.Instance().GetCategoriesHierarchy(portalId);
        }

        /// <summary>
        /// Inserts a collection of <see cref="ListItem"/> into a <see cref="System.Web.UI.WebControls.ListControl"/>.
        /// Each item has a value of the name of the category plus ticks to indicate hierarchy between categories.
        /// Each item has a value of the category's itemId.
        /// If you have problems showing all Categories, you can try using <see cref="DisplayChildren(ListControl, int, int?)"/> on an instantiated ItemRelationship (see <see cref="Controls.ItemRelationships.UpdateAvailableItems"/> for an example).
        /// </summary>
        /// <param name="lc">The <see cref="System.Web.UI.WebControls.ListControl"/> into which the category options will be added.</param>
        /// <param name="categoryId">The id of the parent category from which the hierarchy will start, or -1 if all categories.</param>
        /// <param name="portalId">The id of the portal in which these categories reside.</param>
        /// <param name="includeParentCategory">if set to <c>true</c> includes the parent category in the list, otherwise only shows the parent's children.  This is ignored if the TopLevelCategory is selected.</param>
        /// <param name="itemToExclude">An item which you want to exclude from the list (including its children).  This is typically used to keep circular relationships from being possibe options.</param>
        public static void DisplayCategoryHierarchy(ListControl lc, int categoryId, int portalId, bool includeParentCategory, int itemToExclude)
        {
            DataTable dt;

            if (categoryId < 1)
            {
                dt = Category.GetCategoriesHierarchy(portalId);

                // we ignore includeParentCategory if it is the TopLevelCategory
            }
            else
            {
                dt = Item.GetAllChildren(ItemType.Category.GetId(), categoryId, RelationshipType.ItemToParentCategory.GetId(), portalId).Tables[0];

                if (includeParentCategory)
                {
                    Category parentCategory = Category.GetCategory(categoryId, portalId);
                    if (parentCategory != null)
                    {
                        DataRow parentRow = dt.NewRow();
                        parentRow["ParentItemId"] = "-1";
                        parentRow["ItemId"]       = categoryId;
                        parentRow["Name"]         = parentCategory.Name;
                        dt.Rows.InsertAt(parentRow, 0);
                    }
                }
            }

            TreeNode root = BuildHierarchy(dt);

            FillListControl(root, lc, itemToExclude);
        }