XmlReader Value don't go through my If-Statement but it should

I have a .graphml Parser written and at one point I need to read out the Attribute Values from a specific tag. The Graphml file looks like this:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<graphml xmlns="http://graphml.graphdrawing.org/xmlns" xmlns:java="http://www.yworks.com/xml/yfiles-common/1.0/java" xmlns:sys="http://www.yworks.com/xml/yfiles-common/markup/primitives/2.0" xmlns:x="http://www.yworks.com/xml/yfiles-common/markup/2.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:y="http://www.yworks.com/xml/graphml" xmlns:yed="http://www.yworks.com/xml/yed/3" xsi:schemaLocation="http://graphml.graphdrawing.org/xmlns http://www.yworks.com/xml/schema/graphml/1.1/ygraphml.xsd">
  <!--Created by yEd 3.19.1-->
  <key for="port" id="d0" yfiles.type="portgraphics"/>
  <key for="port" id="d1" yfiles.type="portgeometry"/>
  <key for="port" id="d2" yfiles.type="portuserdata"/>
  <key attr.name="url" attr.type="string" for="node" id="d3"/>
  <key attr.name="description" attr.type="string" for="node" id="d4"/>
  <key for="node" id="d5" yfiles.type="nodegraphics"/>
  <key for="graphml" id="d6" yfiles.type="resources"/>
  <key attr.name="url" attr.type="string" for="edge" id="d7"/>
  <key attr.name="description" attr.type="string" for="edge" id="d8"/>
  <key for="edge" id="d9" yfiles.type="edgegraphics"/>
  <graph edgedefault="directed" id="G">
    <node id="n0">
      <data key="d5">
        <y:UMLClassNode>
          <y:Geometry height="116.0" width="131.0" x="1301.3333333333333" y="41.0"/>
          <y:Fill color="#FFCC00" transparent="false"/>
          <y:BorderStyle color="#000000" type="line" width="1.0"/>
          <y:NodeLabel alignment="center" autoSizePolicy="content" fontFamily="Dialog" fontSize="12" fontStyle="bold" hasBackgroundColor="false" hasLineColor="false" height="18.701171875" horizontalTextPosition="center" iconTextGap="4" modelName="internal" modelPosition="c" textColor="#000000" verticalTextPosition="bottom" visible="true" width="60.689453125" x="35.1552734375" xml:space="preserve" y="3.0">&lt;&lt;interface&gt;&gt;Employee</y:NodeLabel>
          <y:UML clipContent="true" constraint="" hasDetailsColor="false" omitDetails="false" stereotype="" use3DEffect="true">
            <y:AttributeLabel xml:space="preserve">+name:string
+age:int</y:AttributeLabel>
            <y:MethodLabel xml:space="preserve">getName(value:string):String
getTitle():String
getStaffNo():Number
getRoom():String
getPhone()</y:MethodLabel>
          </y:UML>
        </y:UMLClassNode>
      </data>
    </node>
  </graph>
  <data key="d6">
    <y:Resources/>
  </data>
</graphml>

My specific needed tag is the <node id="n0"> Now I need the information of the id Attribute.

So my Parser Code for this section looks like this:

public List<string> getNodeAttributeValue(XmlReader reader)
        {
            List<string> id = new List<string>();

            while (reader.Read())
            {
                reader.MoveToAttribute("id");
                while (reader.ReadAttributeValue())
                {
                    if (xmlReader.Value.Contains('n'))
                    {
                        string idElement = xmlReader.Value;
                        id.Add(idElement);
                        return id;
                    }
                }
            }
            return id;
        }

When I compile this the id is always null. With Breakpoints and going slow through compiling I can see that the reader.Value is this: "n0\"\but why is this Value not going through the if Statement? it contains a character of 'n'.

Is the whitespacing a problem? If yes how can I add Whitespacing Settings to my reader without creating a new one? just adding the settings and removing them after reading the information.