也许是我，但看来如果您有XSD

<?xml version="1.0" encoding="utf-8"?>
<xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xs:element name="User">
        <xs:complexType>
            <xs:sequence>
                <xs:element name="GivenName" />
                <xs:element name="SurName" />
            </xs:sequence>
            <xs:attribute name="ID" type="xs:unsignedByte" use="required" />
        </xs:complexType>
    </xs:element>
</xs:schema>

<?xml version="1.0" encoding="utf-8" ?>
<User ID="1">
    <GivenName></GivenName>
    <SurName></SurName>
</User>

<?xml version="1.0" encoding="utf-8" ?>
<User ID="1">
    <SurName></SurName>
    <EmailAddress></EmailAddress>
    <GivenName></GivenName>
</User>

最佳答案

您的问题有解决方案，但不会很漂亮。原因如下:

违反不确定性内容模型

您已经触及到W3C XML Schema的灵魂。您要问的是-可变顺序和可变未知元素-违反了XSD的最困难但最基本的原则，非歧义规则，或更正式地说，是Unique Particle Attribution Constraint:

A content model must be formed such that during validation [..] each item in the sequence can be uniquely determined without examining the content or attributes of that item, and without any information about the items in the remainder of the sequence.

Error: Multiple definition of element 'http://example.com/Chad:SurName' causes the content model to become ambiguous. A content model must be formed such that during validation of an element information item sequence, the particle contained directly, indirectly or implicitly therein with which to attempt to validate each item in the sequence in turn can be uniquely determined without examining the content or attributes of that item, and without any information about the items in the remainder of the sequence.

<xs:element name="User">
    <xs:complexType>
        <xs:sequence>
            <xs:any minOccurs="0" processContents="lax" namespace="##other" />
            <xs:choice>
                <xs:sequence>                        
                    <xs:element name="GivenName" />
                    <xs:any minOccurs="0" processContents="lax" namespace="##other" />
                    <xs:element name="SurName" />
                </xs:sequence>
                <xs:sequence>
                    <xs:element name="SurName" />
                    <xs:any minOccurs="0" processContents="lax" namespace="##other" />
                    <xs:element name="GivenName" />
                </xs:sequence>
            </xs:choice>
            <xs:any minOccurs="0" processContents="lax" namespace="##any" />
        </xs:sequence>
        <xs:attribute name="ID" type="xs:unsignedByte" use="required" />
    </xs:complexType>
</xs:element>

<xs:element name="User2">
    <xs:complexType>
        <xs:sequence>
            <xs:element name="GivenName" />
            <xs:element name="SurName" />
            <xs:element name="ExtendedInfo" minOccurs="0">
                <xs:complexType>
                    <xs:sequence>
                        <xs:any minOccurs="0" maxOccurs="unbounded" processContents="lax" namespace="##any" />
                    </xs:sequence>
                </xs:complexType>
            </xs:element>
        </xs:sequence>
    </xs:complexType>
</xs:element>

关于xml - 使用XSD验证XML……但仍然允许扩展，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/3347822/