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c#dependency-injectionprism

Prism: Inject service in a parameterless constructor

I have three classes:

  • MyModel (pure POCO object)
  • MyModelWrapper (inherits from BindableBase)
  • MyViewModel (it also inherits from Bindable class)

The problem I have is that I need a paremeterless constructor in MyModelWrapper because I bind an object in MyViewModel which is an ObservableCollection<MyModelWrapper> to a Datagrid Itemssource, and if it has not a parameterless constructor, you are not able to insert new rows in it (it does not appear a blank line at the end of the Datagrid).

So, if I want the user can insert new rows I need a parameterless constructor (and I do want).

And here I have my problem: I need to inject a service in MyModelWrapper.

I can inject the service in the constructor:

IMyModelWrapperService Service;
public MyModelWrapper(IMyModelWrapperService Service)
{
    Service = service;
}

But this way the Datagrid does not let the user to insert new rows.

If I could get a reference to the container, I could do container.Resolve<IMyModelWrapper>(), but I think that I would need to inject the container via constructor too, so it is not a valid solution.

So, I would need something like:

[Inject]
IMyModelWrapperService Service;

But I think property injection does not work in Prism (at least I am not able to use it).

Which is the right approach to inject a service in a class that needs to be parameterless in Prism?

Thank you

Solution

  • If you absolutely have to, you can access the container through Prism.Ioc.ContainerLocator.Container to get what you need.

    Yes, this is evil and ugly, but if you need a dependency in a class whose construction you can't control, then this is your only option.

    This is nearly a duplicate of this closed question.