I have a folder full of XHTML files, and a console program to process them.

The problem is, it doesn't work when I'm offline, because

The remote name could not be resolved: 'www.w3.org'

A number of sites, including this one, say to set the XmlResolver to null. That is not not working.

I have tried setting the XmlResolver to null every way that I can think of: in the XmlDocument, in XmlTextReader, and in the XmlReaderSettings. I believe that it's just creating a default instance. I have also tried implementing my own XmlResolver, but I don't know what to return for external items.

public class NonXmlResolver : XmlUrlResolver
{
    public override object GetEntity( Uri absoluteUri, string role, Type ofObjectToReturn )
    {
        if ( absoluteUri.Scheme == "http" )
            throw new Exception("What you talking 'bout, Willis?");
        else
            return base.GetEntity( absoluteUri, role, ofObjectToReturn );
    }
}

The documents do not use any special entities, only pure XML. This is possible, right?