dotnetrdf xml exception using QueryWithResultSet

问题:

I have an asp.net project in which, I would like to query DBPedia. Using the following code I am getting an error:

public string testEndpoint()
    {

        //TEST02
        SparqlRemoteEndpoint endpoint = new SparqlRemoteEndpoint(new Uri("http://dbpedia.org/sparql"), "http://dbpedia.org");
        string res = "";
        //Make a SELECT query against the Endpoint
        SparqlResultSet results = endpoint.QueryWithResultSet("SELECT ?year WHERE {dbpedia:Rihanna dbpedia-owl:birthYear ?year}");

        foreach (SparqlResult result in results)
        {
            res = result.ToString();    
            Console.WriteLine(result.ToString());}

Error message: "An exception of type 'System.Xml.XmlException' occurred in dotNetRDF.dll but was not handled in user code".

Even if I handle the exception the method cannot be executed. Regarding the details it says that there is an invalid XML-version 1.1.

As the XML comes from DBPedia I don't know how to change the xml version or how else I can handle this problem.

回答1:

Virtuoso, which is the triple store used behind the dbpedia SPARQL endpoint, has updated its XML result generation. They replaced the XML version 1.0 with 1.1 in this commit. This causes the exception in the dotNetRDF parser.

Later on Virtuoso reverted the changes in the XML header. Hopefully DBPedia will update their binaries soon, so the old XML header appears again in the SPARQL results.

Source: http://github.com/openlink/virtuoso-opensource/issues/405