[SPARQL错误，直到获得所有超类的根c＃为止

Question

嗨，我想获得子类的所有超类，直到成为根，我使用RDFDotNet，这是我的代码：

   string GetSuperClassesUntilRoot = @"
  PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> 
  PREFIX owl: <http://www.w3.org/2002/07/owl#> 
  PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> 
PREFIX : <" + OntologyUrl + @">
  select ?superclass where {
  <" + Class+ @"> (rdfs:subClassOf|(owl:intersectionOf/rdf:rest*/rdf:first))* ?superclass .
  }
";
                string GetSuperClassesUntilRoot2 = @"
  PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> 
  PREFIX owl: <http://www.w3.org/2002/07/owl#> 
  PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> 
PREFIX : <" + OntologyUrl + @">
  SELECT ?superClass WHERE
{ <" + Class + @"> rdfs:subClassOf* ?superClass .
}
";
 // FILTER (!isBlank(rdfs:subClassOf))
 //FILTER(!isBlank(?superClass))

                Object results = g.ExecuteQuery(GetSuperClassesUntilRoot2);

                if (results is SparqlResultSet)
                {
                    //SELECT/ASK queries give a SparqlResultSet
                    SparqlResultSet rset = (SparqlResultSet)results;

                    foreach (SparqlResult r in rset)
                    {

                        Classes.Add(r["superClass"].ToString());

                        //Do whatever you want with each Result
                    }

                }
                else if (results is IGraph)
                {
                    //CONSTRUCT/DESCRIBE queries give a IGraph
                    IGraph resGraph = (IGraph)results;
                    foreach (Triple t in resGraph.Triples)
                    {

                        //Do whatever you want with each Triple
                    }
                }
                else
                {
                    //If you don't get a SparqlResutlSet or IGraph something went wrong 
                    //but didn't throw an exception so you should handle it here
                    MessageBox.Show("No Data Found.");
                }

我尝试使用某些猫头鹰文件，并且可以正常工作，但是当我使用另一只猫头鹰时，出现错误：

错误消息是：

Unable to Cast object of type 'VDS.RDF.Query.Patterns.FixedBlankNodePattern' to type 'VDS.RDF.Query.Patterns.NodeMatchPattern'

这是owl文件：OWL File我不确定，但是可能是Protege 5.5制作的这个owl文件，因为它无法在Protege 4中打开，如何解决这个问题？请帮我。感谢您的帮助

Answer 1

仅使用API​​而不是尝试自己使用SPARQL对其进行编码可能会更好。参见Using the Ontology API，从中我们可以像这样修改第一个示例：

// First create an OntologyGraph and load in some data
OntologyGraph g = new OntologyGraph();
// TODO: Load your data into the graph using whatever method is appropriate

// Get the class of interest
// TODO: Substitute the correct URI for your class of interest
OntologyClass someClass = g.CreateOntologyClass(new Uri("http://example.org/someClass"));

// Find Super Classes
foreach (OntologyClass c in someClass.SuperClasses)
{
  // TODO: Process the class as appropriate
}

只需为您的应用程序填写适当的TODO。