How to serialize encapsulated class as attributes?

[RogerD]

Hello All,

I have a custom class (Collar) that is a property of another custom
class (Dog) which inherits from (Animal).

I want to serialize Dog and have the properties from Collar appear as
attributes on the Dog xml element.

What I have now:

<Dog>
<Collar collarColor="red" />
</Dog>

What I would like:

<Dog collarColor="red" />

Code sample:

class Animal {
public string Name;
}
class Collar {
public string Color;
}
class Dog : Animal {
//[XmlAttribute()] <-- throws an exception that a complex type can't
be an attribute.
public Collar MyCollar = new Collar();
}
class Kennel {
public Kennel() {
Console.WriteLine(Serialize(NewDog()));
}

public Dog NewDog() {
Dog dog = new Dog();
dog.Name = "Fido";
dog.MyColor.Color = "red";
return dog;
}

private string Serialize(object entity)
{
XmlSerializer serializer = new XmlSerializer(entity.GetType());
StringBuilder sb = new StringBuilder();
StringWriter sw = new StringWriter(sb);
serializer.Serialize(sw, entity);
string xml = sb.ToString();
return xml;
}
}

I want to use Collar on more classes than just Dogs and/or Animals,
which is why it's in its own class. But I want the properties of Collar
to appear as xml attributes of any class I include it in to re-use the
same code in several places.

Any suggestions?

Thanks,
Roger