C#: Create strong reference between objects, without one referencing the other

Question

Suppose I have 2 classes, Foo and Bar. Foo does not have (and cannot have) a relation to Bar.

However, I want a bar instance to stay alive, as long as it\'s foo instance

Answer 1

Can you create a public object field called BarReference in type Foo?
Someone outside of Foo should set the proper instance of Bar to this property.
As long as there is a reference to the bar instance it won't be GCed AND using object Foo doesn't know anything about Bar type.