XML element with "xsi:type" attribute does not validate. It expects a "type" attribute

Question

I have XML that includes an element that has the attribute: xsi:type="AnswerBool". My xsd has that element and has set up an attribute with the name="type" and then restricts the enumeration values to "AnswerBool" (and others). However, when I try to validate the XML it fails. If I change the XML so that the element uses type rather than xsi:type all is well.

XML:

      <Answer xsi:type="AnswerBool">

-1

XSD:

        <xs:element name="Answer" minOccurs="0" maxOccurs="unbounded">
            <xs:complexType>
                <xs:sequence>
                    <xs:element name="Value">
                        <xs:complexType>
                            <xs:simpleContent>
                                <xs:extension base="xs:string">
                                    <xs:attribute name="type">
                                        <xs:simpleType>
                                            <xs:restriction base="xs:string">
                                                <xs:enumeration value="xsd:int"/>
                                            </xs:restriction>
                                        </xs:simpleType>
                                    </xs:attribute>
                                </xs:extension>
                            </xs:simpleContent>
                        </xs:complexType>
                    </xs:element>
                </xs:sequence>
                <xs:attribute name="type" use="optional">
                    <xs:simpleType>
                        <xs:restriction base="xs:string">
                            <xs:enumeration value="AnswerBool"/>
                            <xs:enumeration value="AnswerMsc2DTO"/>
                        </xs:restriction>
                    </xs:simpleType>
                </xs:attribute>
            </xs:complexType>
        </xs:element>

I tried to name the "type" attribute to "xsi:type" but I am not allowed to have a ':' in the name. Unfortunately I cannot update the XML to NOT use "xsi:" before "type". I know what I am doing is basically some sort of work around to allow multiple different types for my "Answer" element. So I might be pushing things too far to get this all to work. However...

Does anyone have any ideas as to how I can get my XML to validate?

I mean is there a way to include the "xsi:" in my attribute's name or perhaps is there a way to have the validation process only look at the "type" part and ignore the "xsi:"?

Answer 1

xsi, here is the prefix indicating the xmlns, i.e. the namespace

The xml input is probably missing a reference to the corresponding namespace.

typically, xsi is used for the Schema-instance namespace.

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

Answer 2

First, xsi is the prefix conventionally given for the schema instance, so don't change that.

Second, the purpose of xsl:type is to designate that a particular element has a particular type from an XML Schema. In the fragment of the schema you showed, "Answer" is the only schema type. "AnswerBool" and "AnswerMsc2DTO" are values that an attribute declared type could have, but that "type" isn't the same as the xsi:type.

So in your file, you should use type if the XML file and the schema are both in the same (default) namespace.

Hope that helps.