Introduction:
WPF includes a strong data-binding architecture. We will be able to design a strong scalable architecture if we use the MVVM paradigm and decouple our views with dependency injection.
The view has an injected viewmodel that is specific to the DataContext. Within the container, the services exist as singletons.
This approach is frequently used while WPF application development to enable loosely connected views to interact elegantly over shared data from background services. Because perspectives must depend on one another, reorganizing or replacing them is straightforward.
With this design, you can create loosely connected views that interact beautifully together over shared data from background services. Because views must depend on one another, it is quite simple to reorganize or replace them.
What is WPF?
Windows Presentation Foundation is a user interface foundation used to create desktop client applications. The WPF development platform includes an application model, resources, controls, graphics, layout, data binding, security, and documents.
What exactly is MVVM?
MVVM is a pattern used when working with views built mostly with WPF technology. As a result, prior experience with WPF and its bindings would be quite beneficial.
Benefit :
The key advantage of employing dependency injection is that it allows for loose connectivity between modules. We will have modules built independently by various developers thanks to loose coupling. It also means that testing is typically simplified since mock-up objects are injected into the module being tested, substituting the essential objects. Loose coupling also suggests that we will alter or replace the implementation of essential objects with others while affecting or changing the appliance as little as possible.
Another advantage is the automated life-cycle management of IoC Container-created objects. We should not know when to form and delete necessary items.
Architecture
Before we start looking at any code let's understand why we want to use Dependency Injection and Model-View-ViewModel (MVVM) as these are 2 very different patterns that are often used together to solve different problems.
Dependency InjectionModel-View-ViewModel (MVVM)What is a Dependency Injection?
Dependency Injection (DI) is a design paradigm that may be used to implement IoC. It enables the generation of dependent items outside of a category and gives those objects to a category in different ways. With DI, we transfer the creation and binding of dependent items outside of the category on which they are reliant.
Dependency Injection is a kind of Inversion of Control from the object-oriented programming concepts of SOLID. It enables your system to inject instantiated objects into a category constructor while having no knowledge of the instantiated items. There are several libraries and frameworks that might help with this, however, we will rely on the community.
S - Single Responsibility Principle
O – Open-Closed Principle
L - Liskov Substitution Principle
I - Interface Segregation Principles
D - Dependency Inversion Principle
If you're unacquainted with the SOLID principles, I've got provided short descriptions and a few examples to assist. Dependency Injection is an implementation of the Dependency Inversion Principle.
Now that you have a basic MVVM implementation that works, it's time to start working with a Dependency Injection implementation. There are other libraries and frameworks that might accomplish this, however, we will utilize the Microsoft community library. Microsoft.Extensions. DependencyInjection is quickly becoming a standard library across many open source and closed source projects in the.NET ecosystem; it's a nice library that supports many of the common Dependency Injections features straight out of the box.
Let's get started
Add NuGet Reference for Microsoft.Extensions.DependencyInjectionCreate a containerCreate MessageServiceRegister MessageService to ContainerInject MessageService into MainViewModelAdd NuGet References
Begin by including the NuGet packages in all or any of the projects. From the solution explorer, right-click on the answer level and select Manage NuGet. After you've got the search bar open, go ahead and look for Microsoft. Extensions. DependencyInjection.
Which type of issues can be resolved by Dependency Injection?
Assume you have a view model that obtains data from data services.
public class MyViewModel
{
MyService dataService;
public UserViewModel() {
this.dataService = new MyService();
}
}
The view model is dependent on service, implying that MyService is MyViewModel's dependence. Although it is quite simple to establish the service right within the view model class, there are numerous disadvantages to doing so:
The two courses are intricately intertwined. When you use MyViewModel, it creates an instance of MyService for you.If you alter the way MyService is started in the future, you must update any view models that use MyService.Since MyViewModel is dependent on MyService, you cannot build a unit test for it. If a test fails, you won't know if the issue is with MyViewModel or MyService.You can avoid these issues if you pass MyService to the MyViewModel’s constructor:
public class MyViewModel
{
MyService dataService;
public MyViewModel(MyService dataService) {
this.dataService = dataService;
}
}
This method also has flaws:
Various view models are produced in each class, and each of them must understand how to construct MyService. It is impossible to share the same instance of between numerous view models without adding a static property.
The primary need for dependency injection is to centrally resolve all dependencies. This implies that you need simply include a separate block in your application to create new class instances and give arguments to them.
Although you will write your own logic for It, it is far more convenient to use a DI framework to help avoid/eliminate boilerplate code.
The dependency injection pattern has several benefits:
Courses are loosely plus one another. As a consequence, you'll be able to adjust dependencies with ease. Replace MyService with MyServiceEx, for example.Unit tests are simple to write since mock parameters are passed to tested classes.Because you generally know where all dependencies are maintained, your project is properly organized.Here we add Dependency Injection to the WPF application.
Many excellent frameworks are available in the.NET community to help you implement the Dependency Injection technique in your application. These frameworks have two key characteristics:
Classes can be registered in containers, and objects with initialized dependencies can be created.
Containers are the main objects of DI frameworks that discover and resolve class dependencies automatically.
Some frameworks allow arguments to be injected into class properties, but the most frequent method is to inject parameters into a constructor.
Conclusion :
There are plenty of topics happening during this article, creating both straightforward MVVM application that leverages advanced Dependency Injection techniques. If you bought lost along the way or find it easier to be told from a code to the sample and head over to the GitHub link below and download all the code from this text.