What is the good way of sharing specific data between ViewModels

Posted by voroninp on Programmers See other posts from Programmers or by voroninp
Published on 2012-12-03T13:01:31Z Indexed on 2012/12/03 17:18 UTC
Read the original article Hit count: 200

Filed under:

design-patterns

|

wpf

|

mvvm

We have IAppContext which is injected into ViewModel.
This service contains shared data: global filters and other application wide properties.

But there are cases when data is very specific. For example one VM implements Master and the second one - Details of selected tree item. Thus DetailsVm must know about the selected item and its changes.

We can store this information either in IAppContext or inside each concerned VM. In both cases update notifications are sent via Messenger.

I see pros and cons for any of the approaches and can not decide which one is better.

1st:
+ explicitly exposed shared proerties, easy to follow dependencies
- IAppContxt becomes cluttered with very specific data.

2nd:
the exact opposite of the first and more memory load due to data duplication.

May be someone can offer design alternatives or tell that one of the variants is objectively superior to the other cause I miss something important?

© Programmers or respective owner

Related posts about design-patterns

Should universities put more emphasis on teaching their students about design patterns?

as seen on Programmers - Search for 'Programmers'
While I've heard about design patterns being mentioned in a few courses at uni, I know of only a single course which actually teaches design patterns. In almost all other areas (algorithms, parallelism, architecture, dynamic languages, paradigms, etc), there are several, often a basic course and an… >>> More
Podcasts on GoF design patterns

as seen on Stack Overflow - Search for 'Stack Overflow'
Anyone know of a good podcast on design patterns? >>> More
How often are design patterns used in the workplace using PHP

as seen on Stack Overflow - Search for 'Stack Overflow'
Hey everyone, I read a book awhile back called PHP Design Patterns and Practice, and ever since then I have been using design patterns whenever I think they are needed. However it just occurred to me that maybe most companies do not use design patterns very often for PHP, or at all. What I was wondering… >>> More
Who benefits from the use of Design Patterns?

as seen on DotNetBlocks - Search for 'DotNetBlocks'
Who benefits from the use of design patterns is like asking who benefits from clean air or a good education. All of the stakeholders of a project benefit from the use of design patterns. Project Sponsor Project sponsors benefit from the use of design patterns because they promote reduced development… >>> More
Architect: "Collaborating on Design Patterns"

as seen on Oracle Technology Network - Search for 'Oracle Technology Network'
It takes an architect community to raise a collection of SOA design patterns. >>> More

Related posts about wpf

C#/WPF - RoutedEvent in WPF class that isn't a UIElement

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a class that needs to notify that something significant has occured. The class is in a WPF-project, even though this specific class, is lookless (and doesn't inherit from UIElement, neither directly or indirectly). Normally, I just register a RoutedEvent to get this functionality but as this… >>> More
How to pass value from wpf form to wpf user control

as seen on Stack Overflow - Search for 'Stack Overflow'
Hai am having a WPF user control in my WPF Form, when i click my button in my form , i just want to pass some value to the textbox which is in the usercontrol, tell me how to do this. >>> More
WPF opening up exe program within WPF window

as seen on Stack Overflow - Search for 'Stack Overflow'
Not sure if this is possible but is there a way to open up another program like notepad within the container of a WPF window? similiar to that of being able to open a web page using the webbrowser control? Basically I would like to open notepad or other exe but keep it constrained within the WPF… >>> More
Silverlight Commands Hacks: Passing EventArgs as CommandParameter to DelegateCommand triggered by Ev

as seen on ASP.net Weblogs - Search for 'ASP.net Weblogs'
Today I've tried to find a way how to pass EventArgs as CommandParameter to DelegateCommand triggered by EventTrigger. By reverse engineering of default InvokeCommandAction I find that blend team just ignores event args.To resolve this issue I have created my own action for triggering delegate commands… >>> More
Building applications with WPF, MVVM and Prism(aka CAG)

as seen on ASP.net Weblogs - Search for 'ASP.net Weblogs'
In this article I am going to walk through an application using WPF and Prism (aka composite application guidance, CAG) which simulates engaging a taxi (cab). The rules are simple, the app would have3 screens A login screen to authenticate the user An information screen. A screen… >>> More