[Mono-list] XmlNamespaceManager.LookupPrefix

[ginga(A.E.)]

Hello,

I noticed that mono's XmlNamespaceManager.LookupPrefix method is
implemented as MS describes in their documentation:

<blockquote>
  Return Value
    The matching prefix. If there is no mapped prefix, the method
    returns String.Empty. If a null value is supplied then a null
    reference (Nothing in Visual Basic) is returned.
</blockquote>

But I simply tried below with MS.NET, then LookupPrefix returned null:

--------
using System;
using System.Xml;

public class NamespaceManagerTest
{
  public static void Main (String[] args) {
    XmlNamespaceManager nsmgr = new XmlNamespaceManager (new NameTable ());
    nsmgr.NameTable.Add ("urn:hoge");
    nsmgr.NameTable.Add ("urn:fuga");
    nsmgr.AddNamespace (string.Empty, "urn:hoge");
    string ns = nsmgr.LookupPrefix ("urn:fuga");
    Console.WriteLine ((ns == null).ToString ());          // TRUE!!
    ns = nsmgr.LookupPrefix ("urn:hoge");
    Console.WriteLine ((ns == String.Empty).ToString ());  // TRUE
  }
}
--------

I think that LookupPrefix *should* return null (rather than
String.Empty) as MS implementation does.
Otherwise, we cannot identify "default namespace" from no match.

Does anyone think different or have any hints and/or opinion?


Thanks,

-- Atsushi Eno