如何从IGraph中读取变量

Question

有没有办法从我使用DotNetRDF创建的IGraph中读取“类别”值？ （查看下面导入的RDF文件）

这是代码（作为图像）：

这是代码（作为文本而不是图像）：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE rdf:RDF [
    <!ENTITY rdf 'http://www.w3.org/1999/02/22-rdf-syntax-ns#'>
    <!ENTITY rdfs 'http://www.w3.org/2000/01/rdf-schema#'>
    <!ENTITY owl 'http://www.w3.org/2002/07/owl#'>
    <!ENTITY swivt 'http://semantic-mediawiki.org/swivt/1.0#'>
    <!ENTITY wiki 'http://www.projectenportfolio.nl/wiki/index.php/Speciaal:URIResolver/'>
    <!ENTITY category 'http://www.projectenportfolio.nl/wiki/index.php/Speciaal:URIResolver/Category-3A'>
    <!ENTITY property 'http://www.projectenportfolio.nl/wiki/index.php/Speciaal:URIResolver/Property-3A'>
    <!ENTITY wikiurl 'https://www.projectenportfolio.nl/wiki/index.php/'>
]>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xmlns:owl="http://www.w3.org/2002/07/owl#" xmlns:swivt="http://semantic-mediawiki.org/swivt/1.0#" xmlns:wiki="http://www.projectenportfolio.nl/wiki/index.php/Speciaal:URIResolver/" xmlns:category="http://www.projectenportfolio.nl/wiki/index.php/Speciaal:URIResolver/Category-3A" xmlns:property="http://www.projectenportfolio.nl/wiki/index.php/Speciaal:URIResolver/Property-3A">

    <owl:Ontology>
        <swivt:creationDate rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2017-05-30T13:18:55+02:00</swivt:creationDate>
        <owl:imports rdf:resource="http://semantic-mediawiki.org/swivt/1.0"/>
    </owl:Ontology>
    <owl:Class rdf:about="http://www.projectenportfolio.nl/wiki/index.php/Speciaal:URIResolver/Category-3AHandelingsperspectief">
        <rdfs:label>Handelingsperspectief</rdfs:label>
        <swivt:page rdf:resource="https://www.projectenportfolio.nl/wiki/index.php/Categorie:Handelingsperspectief"/>
        <rdfs:isDefinedBy rdf:resource="https://www.projectenportfolio.nl/wiki/index.php/Speciaal:RDFExporteren/Categorie:Handelingsperspectief"/>
        <swivt:wikiNamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">14</swivt:wikiNamespace>
        <swivt:wikiPageModificationDate rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2016-06-24T11:13:57Z</swivt:wikiPageModificationDate>
        <property:Modification_date-23aux rdf:datatype="http://www.w3.org/2001/XMLSchema#double">2457563.9680208</property:Modification_date-23aux>
        <property:Has_default_form rdf:resource="http://www.projectenportfolio.nl/wiki/index.php/Speciaal:URIResolver/Formulier-3AHandelingsperspectief"/>
        <swivt:wikiPageSortKey rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Handelingsperspectief</swivt:wikiPageSortKey>
        <rdfs:subClassOf rdf:resource="http://www.projectenportfolio.nl/wiki/index.php/Speciaal:URIResolver/Category-3AActivity"/>
        <rdfs:subClassOf rdf:resource="http://www.projectenportfolio.nl/wiki/index.php/Speciaal:URIResolver/Category-3AEMont_core"/>
    </owl:Class>
    <swivt:Subject rdf:about="http://www.projectenportfolio.nl/wiki/index.php/Speciaal:URIResolver/OLmK_HP_Abc">
        <rdf:type rdf:resource="http://www.projectenportfolio.nl/wiki/index.php/Speciaal:URIResolver/Category-3AHandelingsperspectief"/>
        <rdfs:label>OLmK HP Abc</rdfs:label>
        <swivt:page rdf:resource="https://www.projectenportfolio.nl/wiki/index.php/OLmK_HP_Abc"/>
    </swivt:Subject>