HtmlAgilityPack.HtmlWeb.GetContentTypeForExtension C# (CSharp) Method

        public static string GetContentTypeForExtension(string extension, string def)
        {
            if (string.IsNullOrEmpty(extension))
            {
                return def;
            }
            string contentType = "";

            if (!SecurityManager.IsGranted(new RegistryPermission(PermissionState.Unrestricted)))
            {
                if (MimeTypes.ContainsKey(extension))
                    contentType = MimeTypes[extension];
                else
                    contentType = def;
            }

            if (!SecurityManager.IsGranted(new DnsPermission(PermissionState.Unrestricted)))
            {
                //do something.... not at full trust
                try
                {
                    RegistryKey reg = Registry.ClassesRoot;
                    reg = reg.OpenSubKey(extension, false);
                    if (reg != null) contentType = (string)reg.GetValue("", def);
                }
                catch (Exception)
                {
                    contentType = def;
                }
            }
            return contentType;
        }