public static List<IHtmlSchema> GetSchemas()
        {
            HtmlSchemaManager mng = new HtmlSchemaManager();
            IHtmlSchema html = mng.GetSchema("http://schemas.microsoft.com/intellisense/html");

            var schemas = mng.CustomAttributePrefixes.SelectMany(p => mng.GetSupplementalSchemas(p)).ToList();
            schemas.Insert(0, html);

            return schemas;
        }
        public static List<IHtmlSchema> GetSchemas()
        {
            HtmlSchemaManager mng = new HtmlSchemaManager();
            IHtmlSchema html = mng.GetSchema("http://schemas.microsoft.com/intellisense/html");

            var schemas = mng.CustomAttributePrefixes.SelectMany(p => mng.GetSupplementalSchemas(p)).ToList();
            schemas.Insert(0, html);

            return schemas;
        }