XSD tool appends “Specified” to certain properties/fields when generating C# code

Question

I got a strange behaviour with the XSD generator I can't really explain. I got an XSD like this:

<xs:complexType name="StageSequenceElement" mixed="false">
    <xs:complexContent>
        <xs:extension base="CoreObject">
            <xs:sequence>
                <xs:element name="Description" type="xs:string" minOccurs="0">
                    <xs:annotation>
                        <xs:documentation>Some Doc</xs:documentation>
                    </xs:annotation>
                </xs:element>
                <xs:element name="StageRef" type="ObjectReference">
                    <xs:annotation>
                        <xs:documentation>...</xs:documentation>
                    </xs:annotation>
                </xs:element>
                <xs:element name="MinDuration_100ms" type="xs:int" nillable="true" minOccurs="0">
                    <xs:annotation>
                        <xs:documentation>...</xs:documentation>
                    </xs:annotation>
                </xs:element>
                <xs:element name="MaxDuration_100ms" type="xs:int" nillable="true">
                    <xs:annotation>
                        <xs:documentation>...</xs:documentation>
                    </xs:annotation>
                </xs:element>
                <xs:element name="StageOnDemand" type="xs:boolean" nillable="true" minOccurs="0">
                    <xs:annotation>
                        <xs:documentation>...</xs:documentation>
                    </xs:annotation>
                </xs:element>
            </xs:sequence>
        </xs:extension>
    </xs:complexContent>
</xs:complexType>

it is derived from CoreObject:

<xs:complexType name="CoreObject">
    <xs:sequence>
        <xs:element name="No" type="xs:int">
            <xs:annotation>
                <xs:documentation>...</xs:documentation>
            </xs:annotation>
        </xs:element>
    </xs:sequence>
</xs:complexType>

This is just a small part of the XSD, there are a lot more complex types.

So when I generate the classes similar to this, I get a generated class which has two more properties (in addition to the 5 which I would expect):

public bool MinDuration_100msSpecified

and

public bool StageOnDemandSpecified

So to the "original" property "Specified" was appended and the type is now bool. Can anyone explain why this is so?

Answer 1

the bool attribute means the related attribute should be serialized.

e.g.

If the bool MinDuration_100msSpecified is set to false, and you set the MinDuration_100ms to be 300, when you use XmlSerializer to serialize the object, the MinDuration_100ms attribute won't be serialized.

This feature can save the serialized xml file to be minimal.

Answer 2

Set minOccurs="1" where element is nillable. For example:

<xs:element name="StageOnDemand" type="xs:boolean" nillable="true" minOccurs="1" />