private void ValidateUrlList()
{
//if another site already uses one of our urls, throw an exception
foreach (var url in UrlList.Keys.Where(url => PortalContext.Sites.Keys.Count(k => k == url && PortalContext.Sites[k].Id != this.Id) > 0))
{
throw new ApplicationException(string.Format("The url {0} is already used by the site {1}", url, PortalContext.Sites[url].DisplayName));
}
}
