test03.xml
<?xml version="1.0" encoding="UTF-8"?>
<item name="love" parentitem="" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="test03.xsd">
 <att datatype="title" name="lovetitle">Love</att>
 <att datatype="dropdown" name="art" size="5" multiple="multiple">
  <att datatype="option" name="book" value="book">
   <ctrldata>
    <poem value="poem">
     <jone value="jone"/>
    </poem>
    <poem value="poem">
     <jone value="jone"/>
    </poem>
   </ctrldata>
  </att>
  <att datatype="option" name="painting" value="painting" selected="selected"/>
 </att>
</item>

test03.xsd
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<!--W3C Schema 由 XMLSpy v2006 U 创建 (http://www.altova.com)-->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">
 <xs:element name="att">
  <xs:complexType mixed="true">
   <xs:choice minOccurs="0" maxOccurs="unbounded">
    <xs:element ref="att"/>
    <xs:element ref="ctrldata"/>
   </xs:choice>
   <xs:attribute name="datatype" type="xs:string" use="required"/>
   <xs:attribute name="name" type="xs:string" use="required"/>
   <xs:attribute name="size" type="xs:byte"/>
   <xs:attribute name="multiple" type="xs:string"/>
   <xs:attribute name="value" type="xs:string"/>
   <xs:attribute name="selected" type="xs:string"/>
  </xs:complexType>
 </xs:element>
 <xs:element name="ctrldata">
  <xs:complexType>
   <xs:sequence>
    <xs:any processContents="skip" minOccurs="0" maxOccurs="unbounded"/>
   </xs:sequence>
  </xs:complexType>
 </xs:element>
 <xs:element name="item">
  <xs:complexType>
   <xs:sequence>
    <xs:element ref="att" maxOccurs="unbounded"/>
   </xs:sequence>
   <xs:attribute type="xs:string" name="name" use="required"/>
   <xs:attribute name="parentitem" type="xs:string" use="required"/>
  </xs:complexType>
 </xs:element>
</xs:schema>

注意:<xs:any processContents="skip" minOccurs="0" maxOccurs="unbounded"/>中的 processContents="skip"不能少