Hastables[
^] are just a form of collection. It is like an associative array. It des not replace references, but it is using references. The hashcode is used do generate a kind of index to the object, but the object itself is linked into the structure by it's reference. If no reference is kept to an object the garbage collector will destroy it. So if you loose all references, you can't access the object anymore. The hashcode is just a calculated property of an object (returned by a method), nothing more.
So, shortly: no.
But why do you think you need this?