How to get UNiagaraParameterCollection from UNiagaraSystem or UNiagaraEmitter?

Hello everyone.
As you know, it is able to add a Niagara Parameter Collection to the Niagara Emitter.

Currently, I want to get a Niagara Parameter Collection in C ++ code.
But I don’t know how to do it.

Which member method can I use to get the Niagara Parameter Collection from Niagara Emitter ?

I have found “Niagara Parameter Collections” is managed by Niagara WorldManager.

I can get an array of Niagara Parameter Collections and their instance from FNiagaraWorldManager.
But parameter value in it is “empty”. The value I set with the editor is not there.

Does anyone know how to rewrite the value of NiagaraParameterCollection at runtime ?
Are there any Epic employees looking here ? I ask for help.