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mvvmviewmodelview-model-pattern

MVVM: Should a ViewModel have a member to another ViewModel?

The dependent ViewModel gets injected via the constructor (IoC container).

Example: ProductSelectionViewModel uses ShoppingBasketViewModel.

Is this a common practice or is this THE recommended way? I don´t think so...

How should it be done right?

Should the view use the 2 ViewModels? Mediator pattern? Event driven?

Personally I don´t like the last one.

Solution

  • There's nothing wrong with a view model having a direct reference to another view model, if it is a required dependency, then injecting it via the constructor is fine.

    If you wish for a view model to be able to create new instances of another view model, then injecting a view model factory type would be the way to go.