Question

Every application contains some settings that are configurable. These settings can more or less put into two categories:

1. Appearance of application: example can be window location, window size, default options on views etc.
2. Business rules: these settings will be used by business logic.

In architecture that I implemented, View has its own project (WPF) and ViewModel has its own project (class library). From the lofical standpoint, View should be responsible of loading / saving view related settings, and ViewModel should be responsible for loading / saving business settings.

View settings are easy to handle. Create needed properties in Settings (app.config), and its easy to you can easily load save them.

However, ViewModel cannot access app.config settings through the built-in mechanisms that are Available in View project.

First idea I had was to make some helper methods that will allow me to read / write settings in app.config from ViewModel. What is your opinion? Am I complicating stuff here, or this is acceptable way of handling applic\tion settings?

Answer 1

There are three ways you could go here.

1. Add a reference to System.Configuration.dll and have your ViewModel project use the ConfigurationManager normally.

2. Have the ViewModel project ask for the configuration information it needs via constructors or other methods of Dependency Inversion, and have the View project pass it in.

3. Put the ViewModels and Views in the main application project.

Personally, I would go for option 3 unless there is some reason they need to be in separate assemblies. If they need to be separate, then I would favor option 1 because it’s simpler.