为何引用xml schema文件后用selectNodes(Exp)返回空值。

同学你好！

这是由于同学xsd文件没有修改呢，老师对同学的xml和xsd都做了修改，同学可以参考一下：

xml：

<?xml version="1.0" encoding="UTF-8"?>
<teaching-plan xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
               xsi:noNamespaceSchemaLocation="plan.xsd">
    <course id="001">
        <course-name>大学英语</course-name>
        <class-hour>36</class-hour>
        <exam-form>考试</exam-form>
    </course>
    <course id="002">
        <course-name>高等数学1</course-name>
        <class-hour>70</class-hour>
        <exam-form>考试</exam-form>
    </course>
    <course id="003">
        <course-name>计算机应用基础</course-name>
        <class-hour>108</class-hour>
        <exam-form>上机考试</exam-form>
    </course>
    <course id="004">
        <course-name>Java编程</course-name>
        <class-hour>100</class-hour>
        <exam-form>上机考试</exam-form>
    </course>
    <course id="005">
        <course-name>艺术插花</course-name>
        <class-hour>25</class-hour>
        <exam-form>开卷考试</exam-form>
    </course>
</teaching-plan>

xsd：

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
>
   <xs:element name="teaching-plan">
      <xs:complexType>
         <xs:sequence>
            <xs:element name="course" maxOccurs="100">
               <xs:complexType>
                  <xs:sequence>
                     <xs:element name = "course-name" type="xs:string"></xs:element>
                     <xs:element name = "class-hour">
                        <xs:simpleType>
                           <xs:restriction base="xs:integer">
                              <xs:minInclusive value="20"></xs:minInclusive>
                              <xs:maxInclusive value="110"></xs:maxInclusive>
                           </xs:restriction>
                        </xs:simpleType>
                     </xs:element>
                     <xs:element name = "exam-form" type = "xs:string"></xs:element>
                  </xs:sequence>
                  <xs:attribute name="id" type="xs:string" use="required"></xs:attribute>
               </xs:complexType>
            </xs:element>
         </xs:sequence>
      </xs:complexType>
   </xs:element>
</xs:schema>

如果我的回答解决了你的疑惑，请采纳，祝学习愉快~

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
          targetNamespace="http://www.w3school.com.cn"
          xmlns="http://www.w3school.com.cn"
          elementFormDefault="qualified">
   <xs:element name="teaching-plan">
       <xs:complexType>
           <xs:sequence>
               <xs:element name="course" maxOccurs="100">
                   <xs:complexType>
                       <xs:sequence>
                           <xs:element name = "course-name" type="xs:string"></xs:element>
                           <xs:element name = "class-hour">
                               <xs:simpleType>
                                   <xs:restriction base="xs:integer">
                                       <xs:minInclusive value="20"></xs:minInclusive>
                                       <xs:maxInclusive value="110"></xs:maxInclusive>
                                   </xs:restriction>
                               </xs:simpleType>
                           </xs:element>
                           <xs:element name = "exam-form" type = "xs:string"></xs:element>
                       </xs:sequence>
                       <xs:attribute name="id" type="xs:string" use="required"></xs:attribute>
                   </xs:complexType>
               </xs:element>
           </xs:sequence>
       </xs:complexType>
   </xs:element>
</xs:schema>