将Silverlight MVVM应用程序移植到AngularJS

Question

We're porting an existing Silverlight application into AngularJS/Typescript.

The application has a classical MVVM structure with data models, view-models and views. The models are somewhat tightly interconnected: for example, there are IObservable<> event streams which notify container models of changes within child models.

Here's what confuses me: in MVVM, everything that binds to view is a view-model. One view-model may have a list of other view-models that it contains. In all AngularJS tutorials for people with WPF/Silverlight background, however, only the $scope is called a view-model. What about the nested objects? Are they just domain data models, and you bind to them directly without any intermediate view-model layer?

Then, there's another question: if my data object changed somehow (for example, some service updates it when receiving data from the network, or it simply does some work based on timer), how do I notify the view that it should be updated?

Answer 1

First, I would like to say that you shouldn't try to match one technology to another technology. Doing an app in C# is not doing an app in Javascript (or any flavor of it) so trying to put a name on how the silverlight things are called on Angular/javascript is not a good idea.

What I would suggest is you (and your team) learn how Angular applications are made, what components are used for what purpose and then port the IDEA to angular. Coding an Angular app like a silverlight app is not a good idea.

Anyway, for the sake of the answer, I'll answer some of your questions since I am familiar with WPF / Silverlight.

In angular there is no real need to implement any observation pattern (there is pubsub).

Normally you have services which do a couple of things, like a repository pattern to access your backend or hold your data to use in different pages. Since services are singleton, if you modify it from pageA, pageB will know, so there is no need to tell, that is implicit.

$scope works as a glue between your controller and your view. Since $scope holds POJOs (plain old javascript objects you can put in there anything you need. You can have there nested objects or functions. Then you can use those properties on the $scope in the view without any problem.

If a Service query a backend, it updates the service's data and every controller using that service will automagically get the updated content. The trick here is to know is that you don't have to kill the reference and just update the value.

So, take a little time to learn Angular without having Silverlight in mind, learn what every piece does and start working. That is my advice.