XML Schema for a .NET type that inherits and implements

Question

Hi,

Please consider the following three .NET types: I have an interface, an abstract class, and a concrete class. My question is how to write the XML Schema to include the properties from the interface and from the abstract class.

public interface IStartable
{
    bool RequiresKey { get; set; }

    void Start(object key);
}

public abstract class Vehicle
{
    uint WheelCount { get; set; }
}

public class Car : Vehicle, IStartable
{
    public bool RequiresKey { get; set; }

    public string Make { get; set; }

    publilc string Model { get; set; }


    public Car() {}

    public void Start(object key)
    {
        // start car with key
    }
}

I don't know how to complete this schema:

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
    targetNamespace="cars"
    xmlns="cars"
    xmlns:c="cars">

    <!-- How do I get car to have vehicle's wheelcount
         AND IStartable's RequiresKey? -->
    <xs:element name="Car" type="c:Car" />
    <xs:complexType name="Car">
        <xs:complexContent>
            <xs:extension base="c:Vehicle">
                <xs:group ref=c:CarGroup" />
            </xs:extension>
        </xs:complexContent>
    </xs:complexType>

    <xs:group name="CarGroup">
        <xs:sequence>
            <xs:element name="Make" type="xs:token" />
            <xs:element name="Model" type="xs:token" />
        </xs:sequence>
    </xs:group>

    <xs:complexType name="Vehicle">
        <xs:sequence>
            <xs:element name="WheelCount" type="xs:unsignedInt" />
        </xs:sequence>
    </xs:complexType>

    <xs:complexType name="IStartable">
        <xs:sequence>
            <xs:element name="RequiresKey" type="xs:boolean" />
        </xs:sequence>
    </xs:complexType>

</xs:schema>

Answer 1

I don't really see how you could actually do this in XML schema. XML schema does have inheritance - but only single inheritance, and it doesn't know about interfaces etc.

There's no way in current XML schema to have a class (complex type) be based both on a base class, and at the same time "inherit" from a second "interface" class - XML schema just doesn't have those concepts, sorry.

You might be able to redesign your inheritance a bit - IStartable > Vehicle > Car - then you could model it in XML schema. The current setup is probably just not doable using current XML schema standards.