MVVM: How to pass ObservableCollection to other vi

Question

I'm designing an MVVM framework and I need to know if my understanding of MVVM pattern is correct or not. My question is simple. How should I pass the ObservableCollection object between the VieModels? or shouldn't I?

I have a CustomerViewModel which has an ObservableCollection to hold a list of customers. I also have an InsertCustomerViewModel which is responsible for insertng new customer models in to that ObservableCollection. in the InsertCustomerViewModel I have a method called Insert() which is called everytime the user clicks on the Insert button.

What I'm doing so far is passing the ObsertvableCollection from CustomerViewModel to the constructor of the InsertCustmerViewModel and then in the Insert method I have Items.Add(newCustomer).

Is my implementation correct? or is there any better way to do the job?

Answer 1

From my point of view InsertCustomerViewModel does not make any sense here. When user insert a customer it should only add in CustomerCollection Class which should be a Model for multiple ViewModels.

I think the idea should be share the same CustomerCollection model among the two ViewModels via some common instance.

Answer 2

I would pass the CustomerViewModel to the InsertCustomerViewModel and expose a property for the collection. That way you can use and modify that collection from InsertCustomerViewModel directly.