/// <summary>
/// Retrieves, as an XNamespace in an option, the namespace name in this namespace resolver corresponding to the specified prefix.
/// If the prefix is unknown, the option will be empty.
/// </summary>
/// <param name="namespaceResolver"></param>
/// <param name="prefix"></param>
/// <returns></returns>
public static Opt <XNamespace> GetXNamespaceOpt(this IXmlNamespaceResolver namespaceResolver, string prefix)
{
if (namespaceResolver == null)
{
throw new ArgumentNullException("namespaceResolver");
}
if (prefix == null)
{
throw new ArgumentNullException("prefix");
}
return(namespaceResolver.LookupNamespaceOpt(prefix).SelectFix(ns => XNamespace.Get(ns)));
}
