a String, which may be the same as the property name
for those child objects that are also accessible via a property
Return Value
a child of this group, or null if no such named child object is known
Remarks
A child object will not have a name unless you call AddChildName first, or unless this method is overridden to provide a name. This is frequently overridden when defining a group or node that has well-known parts. Often such parts are also accessible as a property on the class, and the name of the part will be the same as the name of the property. If you override this, you will probably also need to override FindName.