IDeserializationCallback.OnDeserialization(Object sender): Is this syntactic sugar?

开发者_如何转开发From here, an example of using the IDeserializationCallback interface.

void IDeserializationCallback.OnDeserialization(Object sender) 
{
    // After being deserialized, initialize the m_area field 
    // using the deserialized m_radius value.
    m_area = Math.PI * m_radius * m_radius;
}

But this method signature doesn't look familiar to me. The . notation makes me think there is something "tricky" going on here.

What is going on here?

This is called explicit implementation of interface.