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28 changes: 14 additions & 14 deletions docs/core/extensions/dependency-injection-usage.md
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Expand Up @@ -5,6 +5,7 @@ author: IEvangelist
ms.author: dapine
ms.date: 09/23/2020
ms.topic: tutorial
no-loc: [Transient, Scoped, Singleton, Example]
---

# Tutorial: Use dependency injection in .NET
Expand All @@ -22,8 +23,7 @@ In this tutorial, you learn how to:

## Prerequisites

- [.NET Core 3.1 SDK](https://dotnet.microsoft.com/download/dotnet-core) or a later version.
- An Integrated Development Environment (IDE), [Visual Studio, Visual Studio Code, or Visual Studio for Mac](https://visualstudio.microsoft.com) are all valid choices.
- [.NET Core 3.1 SDK](https://dotnet.microsoft.com/download/dotnet-core) or later.
- Familiarity with creating new .NET applications and installing NuGet packages.

## Create a new console application
Expand Down Expand Up @@ -62,25 +62,25 @@ Add the following default implementation for the various operations:

:::code language="csharp" source="snippets/configuration/console-di/DefaultOperation.cs":::

The `DefaultOperation` implements all of the named/marker interfaces and initializes the `OperationId` property to the last four characters of a new globally unique identifier (GUID).
The `DefaultOperation` implements all of the named marker interfaces and initializes the `OperationId` property to the last four characters of a new globally unique identifier (GUID).

## Add service that requires DI

Add the following operation logger object, which acts as a service to your console application:
Add the following operation logger object, which acts as a service to the console app:

*OperationLogger.cs*

:::code language="csharp" source="snippets/configuration/console-di/OperationLogger.cs":::

The `OperationLogger` defines a constructor that requires each of the aforementioned marker interfaces, that is; `ITransientOperation`, `IScopedOperation`, and `ISingletonOperation`. The object exposes a single method that allows the consumer to log the operations with a given `scope` parameter. When invoked, the `LogOperations` method will log each operation's unique identifier with the scope string and message.
The `OperationLogger` defines a constructor that requires each of the aforementioned marker interfaces, that is; `ITransientOperation`, `IScopedOperation`, and `ISingletonOperation`. The object exposes a single method that allows the consumer to log the operations with a given `scope` parameter. When invoked, the `LogOperations` method logs each operation's unique identifier with the scope string and message.

## Register services for DI

Finally, update the *Program.cs* file to match following:
Update *Program.cs* with the following code:

:::code language="csharp" source="snippets/configuration/console-di/Program.cs" range="1-18,35-60" highlight="22-26":::

The application:
The app:

- Creates an <xref:Microsoft.Extensions.Hosting.IHostBuilder> instance with the [default binder settings](generic-host.md#default-builder-settings).
- Configures services and adds them with their corresponding service lifetime.
Expand All @@ -89,7 +89,7 @@ The application:

## Conclusion

The application produces output similar to the following example:
The app displays output similar to the following example:

```console
Scope 1-Call 1 .GetRequiredService<OperationLogger>(): ITransientOperation [ 80f4...Always different ]
Expand All @@ -109,13 +109,13 @@ Scope 2-Call 2 .GetRequiredService<OperationLogger>(): IScopedOperation [ 2bd
Scope 2-Call 2 .GetRequiredService<OperationLogger>(): ISingletonOperation [ 1586...Always the same ]
```

From the application output, you can see that:
From the app output, you can see that:

- Transient operations are always different, meaning a new instance is created with every retrieval of the service.
- Transient operations are always different, a new instance is created with every retrieval of the service.
- Scoped operations change only with a new scope, but are the same instance within a scope.
- Singleton operations are always the same, meaning a new instance is only created once.
- Singleton operations are always the same, a new instance is only created once.

## Next steps
## See also

> [!div class="nextstepaction"]
> [Dependency injection guidelines](dependency-injection-guidelines.md)
* [Dependency injection guidelines](dependency-injection-guidelines.md)
* [Dependency injection in ASP.NET Core](/aspnet/core/fundamentals/dependency-injection)