dx:class 

defines what is the parent class used to validate the content of this element. Additional information may be used to limit the scope of the element, like actual values

Attribute Information

Used By

Complex Type dx:elementType

Source 

<xs:attribute name="class" type="xs:string" use="optional">
  <xs:annotation>
    <xs:appinfo source="§Todo">§todo+xxxdf: possibly link with all the classes from XFT (list generated from schema)</xs:appinfo>
    <xs:documentation xml:lang="en">defines what is the parent class used to validate the content of this element. Additional information may be used to limit the scope of the element, like actual values</xs:documentation>
  </xs:annotation>
</xs:attribute>

Sample