The ASP.NET Core Dependency Injection Project is the first of a few different projects designed to give you expereinces on how to add dependency injection to different ASP.NET Core and Blazor solutions. You will gain experiences in adding default Dependency Injection concepts to an ASP.NET Core Website and in future projects add dependency injection to Blazor Client and Server solutions even with other IoC (Scutor) containers. In this application, you will modify the Counter Razor page so that a concrete implemenation of the 'ISiteCounter' type will get injected into page using the Singleton service lifetime. Note: In a future enhacement, we'll remove the concrete implmentation to the Car List pages and inject those dependencies in as well. This ASP.NET Core application uses Razor pages.

Note: This project is the first in a series, with this project we will start using the build-in dependency injection so that concrete implementations are injected in using different service lifetimes. In a future enhancment, we will be converting the 'Car List' razor page to inject in its concrete implmentations.

If you want to use Visual Studio (highly recommended) follow the following steps:

• If you already have Visual Studio installed make sure you have .Net Core installed by running the "Visual Studio Installer" and making sure ".NET Core cross-platform development" is checked
• Open the .sln file in visual studio
• If you need to install visual studio download it at https://visualstudio.microsoft.com/ (If you're using Windows you'll want to check "ASP.NET" and ".NET Core cross-platform development" on the workloads screen during installation.)
• To run the application simply press the Start Debugging button (green arrow) or press F5
• If you're using Visual Studio on Windows, to run tests open the Test menu, click Run, then click on Run all tests (results will show up in the Test Explorer)
• If you're using Visual Studio on macOS, to run tests, select the Customer.ASPNETCore.UI Project, then go to the Run menu, then click on Run Unit Tests (results will show up in the Unit Tests panel)

(Note: All tests should fail! It's ok. This is supposed to happen. As you complete the project, more of the tests will pass. When you complete the project, all tests should pass)

If you would rather use something other than Visual Studio

• Install the .Net Core SDK from https://www.microsoft.com/net/download/core once that installation completes you're ready to roll!
• To run the application go into the 'Customer.ASPNETCore.UI' project folder and type dotnet run
• To run the tests go into the 'DependencyInjection.Tests' project folder and type dotnet test

• Use Dependency Injection to inject into the Counter page an Interface object
• Add a Singleton lifetime serivce to the website to increase the hit counter on the page.

Note: this isn't the only way to accomplish this, however; this is what the project's tests are expecting. Implementing this in a different way will likely result in being marked as incomplete / incorrect.

• Adding in Dependency Injection to an ASP.NET Core Application
  • Reconfigure the 'Counter.cshtml' razor page for dependency Injection
    • Inject in the 'ISiteCounter' object into the Counter.cshtml.cs file.
      • Add a new private readonly property called '_siteCounter' of type 'ISiteCounter'. (Note : You'll need to add a using statement for Business.Shared)
      • Add a Constructor that accepts a parameter of type ISiteCounter named 'siteCounter'.
      • Initialize the '_siteCounter' field with the 'siteCounter' paramter value within the Constructor
    • In the OnPost method within the Counter.cshtml.cs file add support for increasing the counter and setting the Counter property.
      • Call the 'AddCounter' method on the '_siteCounter' field to increase the counter by 1.
      • Modify the 'Counter' property to get the new current counter value from the 'GetCounter' method from the '_siteCounter' field.
      • Remove the existing process to increase the Counter variable.
  • Register the 'ISiteCounter' service with the concrete Implmentation
    • In the Startup.cs file add support for dependency types
      • In the ConfigureServices method call AddSingleton on services to add support for the 'ISiteCounter' interface to the Concrete implementation of 'SiteCounter'.
      • Import in the missing reference to the Business.Shared library (Note : Short-Cut with Visual Studio - Alt+Enter)
  • Note: The application is now viewable in your browser!

Now is a good time to continue on with other .Net Core Dependency Injection courses to expand your understanding of this topic. You could also take a look at the Dependency injection in ASP.NET Core.