CODEWITHSUNDEEP
c#.netmvvmwindows-phone-8mvvm-light
Lori
Lori

Reputation: 562

Windows Phone 8 MVVM light navigation with non string parameter

I'm am new to the .NET/c# realm and I am trying to develop a Windows Phone 8 application. I have several pages showing lists of Objects(ListPage). All of these pages will have a filter capability, using a commom FilterPage.

What I need is to pass an object from the ListPage to the FilterPage. I want to use MVVM (MVVM light templates). I've managed to implement almost everything using the Messaging framework. I'm using a FilterMessage that takes the object to be passed in its constructor. The ListPage and the FilterViewModel listen to this message. The ListPage will navigate to the FilterPage and The FilterViewModel will take the Object from the message. The ListPage is notified correctly but the FilterViewModel is not notified because the FilterViewModel is created only after the FilterPage is first shown.

Is it possible to initialize the FilterViewModel by App start? If you think that this is not the way to go please tell me why:)

Thanks in advance.

Upvotes: 1

Views: 976

Answers (2)

Lori
Lori

Reputation: 562

I managed to make it work by creating the FilterViewModel instance in the ViewModelLocator constructor.I'm not sure that this is the best way to do it. Hopefully someone with more experience will share with us his thoughts.

public ViewModelLocator()
{
    ServiceLocator.SetLocatorProvider(() => SimpleIoc.Default);

    SimpleIoc.Default.Register<FilterViewModel>();

    ServiceLocator.Current.GetInstance<FilterViewModel>();
}

Upvotes: 1

ArielBH
ArielBH

Reputation: 2001

What I do in this scenario is I'm adding the instance you want to pass around to the other page into the Session object you have under PhoneApplicationService.Current.State.

On the other side after you complete navigation you can extract the instance, and you should remove it from the State.

Pay attention that if your application goes into the background when you have instances inside the State, WP will try to serialize them.

Upvotes: 1

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