Microsoft.Extensions .DependencyInjection .NET 6 (Working With PDF)

Microsoft.Extensions.DependencyInjection is a powerful library provided by Microsoft .NET to facilitate Dependency Injection (DI), a software design pattern that promotes loose coupling and enhances testability in applications. DI is often implemented using .NET Core's built-in DI container or libraries like Autofac, and Unity. DI involves injecting dependencies (objects a class needs) into a class rather than the class creating its dependencies. This is typically done through a constructor, method, or property injection.

Dependency injection container

1. Service registration: Dependencies are registered in a DI container, typically at the application's composition root. These registrations specify how the container should create and manage the dependencies.

2. Dependency Resolution: When a component requests a dependency, the DI container resolves the dependency by creating an instance of a registered type that uses an extension method.

Types of Dependency Injection

• Constructor injection: Registered services are provided to a class through its constructor, which is the most common and recommended form of DI.
• Method injection: Services are resolved and passed as parameters to a method. Property injection: Singleton services or services with a scoped lifetime are assigned to the class.
• Property injection: Singleton services or services with a scoped lifetime can be assigned to class properties. However, this approach is less common and often considered inferior to constructor injection because it can introduce hidden dependencies.

Understanding Lifetimes in Dependency Injection (DI): Scoped, Transient, and Singleton

1. Scoped: Scoped dependencies are created once per request or lifetime scope, meaning the container provides the same instance within a single request or operation. This consistency is particularly useful in web applications, where scoped dependencies help maintain a stable dependency throughout a web request.

2. Transient: Transient dependencies are instantiated each time they are requested from the container. This implies that a new instance of a transient dependency is generated whenever it is needed. Typically, transient dependencies are used for lightweight, stateless services or components.

3. Singleton: Singleton dependencies are instantiated only once and shared throughout the application's entire lifetime. This ensures that the same instance of a singleton dependency is used for all requests throughout the application's duration. Singleton dependencies are typically employed for stateful services or components that need to be universally accessible across the entire application.

Installing Microsoft.Extensions.DependencyInjection package

To start using dependency Injection in a .NET Core project, you first need to install Microsoft.Extensions.DependencyInjection package. This can be done through the NuGet Package Manager Console in Visual Studio with the following code:

Install-Package Microsoft.Extensions.DependencyInjection

Install-Package Microsoft.Extensions.DependencyInjection

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Screenshot

Example: Basic Dependency Injection

In this example, let's create a sample app (console application) wherein we'll utilize a service provider to resolve services and inject them into our program.

using Microsoft.Extensions.DependencyInjection;
using System;
public interface IMessageService
{
    void SendMessage(string message);
}
public class ConsoleMessageService : IMessageService
{
    public void SendMessage(string message)
    {
        Console.WriteLine(message);
    }
}

using Microsoft.Extensions.DependencyInjection;
using System;
public interface IMessageService
{
    void SendMessage(string message);
}
public class ConsoleMessageService : IMessageService
{
    public void SendMessage(string message)
    {
        Console.WriteLine(message);
    }
}

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The code snippet creates a rule for sending messages called IMessageService. It's like setting up a plan for how messages should be sent. Then, the ConsoleMessageService class is made to follow this rule by using Console.WriteLine to send messages. This setup separates the idea of sending messages from the actual process, making it easier to change how messages are sent later if needed. It helps keep the messaging system organized and easy to manage in the application.

class Program
{
    static void Main(string[] args)
    {
        // Create a service provider
        var serviceProvider = new ServiceCollection()
            // Register the service implementation
            .AddTransient<IMessageService, ConsoleMessageService>()
            .BuildServiceProvider();
        // Resolve the service
       var messageService = serviceProvider.GetRequiredService<IMessageService>();
        // Use the service to send a message
        messageService.SendMessage("Hello,From Dependency Injection!");
    }
}

class Program
{
    static void Main(string[] args)
    {
        // Create a service provider
        var serviceProvider = new ServiceCollection()
            // Register the service implementation
            .AddTransient<IMessageService, ConsoleMessageService>()
            .BuildServiceProvider();
        // Resolve the service
       var messageService = serviceProvider.GetRequiredService<IMessageService>();
        // Use the service to send a message
        messageService.SendMessage("Hello,From Dependency Injection!");
    }
}

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This code sets up a serviceProvider to manage tools. It adds a ConsoleMessageService tool to it. Then, it retrieves the IMessageService tool from serviceProvider and uses it to send the message "Hello, Dependency Injection!" to the console.

Output: The program prints the string message "Hello, From Dependency Injection!"

IronPDF: C# PDF Library

IronPDF is a powerful library for C# that simplifies the complex process of PDF generation, offering a wide range of features for PDF manipulation, including the ability to generate PDFs from HTML, the operation of adding text and images, creating secure documents, and much more.

Using IronPDF with Dependency Injection

To integrate the IronPDF library into a .NET Core application leveraging dependency injection features and extension methods with Microsoft.Extensions.DependencyInjection, you can proceed as follows:

1. Create an interface to define your PDF generation service.
2. Implement the interface.
3. Utilize extension methods to register the service in the dependency injection container.
4. Inject the service into your application as required.

Define Interface

Create an interface to define your PDF generation service.

public interface IPdfService
{
    void GeneratePdf(string baseUrl, string query, string filePath);
}

public interface IPdfService
{
    void GeneratePdf(string baseUrl, string query, string filePath);
}

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Implement Interface

Implement the interface using IronPDF for creating the PDF file.

public class IronPdfService : IPdfService
{
    public void GeneratePdf(string baseUrl, string query, string filePath)
    {
        License.LicenseKey = "Your-License-Key";
        string encodedQuery = HttpUtility.UrlEncode(query);
        string fullUrl = $"{baseUrl}?query={encodedQuery}";
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderUrlAsPdf(fullUrl);
        pdf.SaveAs(filePath);
        Console.WriteLine($"PDF successfully created from: {fullUrl}");
        Console.WriteLine($"Saved to: {filePath}");
    }
}

public class IronPdfService : IPdfService
{
    public void GeneratePdf(string baseUrl, string query, string filePath)
    {
        License.LicenseKey = "Your-License-Key";
        string encodedQuery = HttpUtility.UrlEncode(query);
        string fullUrl = $"{baseUrl}?query={encodedQuery}";
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderUrlAsPdf(fullUrl);
        pdf.SaveAs(filePath);
        Console.WriteLine($"PDF successfully created from: {fullUrl}");
        Console.WriteLine($"Saved to: {filePath}");
    }
}

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Register Service

In your Program.cs class, configure dependency injection:

builder.Services.AddSingleton<IPdfService, IronPdfService>();

builder.Services.AddSingleton<IPdfService, IronPdfService>();

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This setup resolves dependencies by implementing the IPdfService interface with IronPdfService, establishing a singleton service type for PDF generation. It is then referenced across the application, ensuring consistent functionality for generating PDFs.

Usage

Inject IPdfService into your controller or service and use it:

public class MyController : Controller
{
    private readonly IPdfService _pdfService;
    public MyController(IPdfService pdfService)
    {
        _pdfService = pdfService;
    }
    public IActionResult GeneratePdf()
    {
        string baseUrl = "https://ironpdf.com/";
        string query = "Hello World from IronPDF !";
        string filePath = "Demo.pdf";
        _pdfService.GeneratePdf(baseUrl, query, filePath);
        return View();
    }
}

public class MyController : Controller
{
    private readonly IPdfService _pdfService;
    public MyController(IPdfService pdfService)
    {
        _pdfService = pdfService;
    }
    public IActionResult GeneratePdf()
    {
        string baseUrl = "https://ironpdf.com/";
        string query = "Hello World from IronPDF !";
        string filePath = "Demo.pdf";
        _pdfService.GeneratePdf(baseUrl, query, filePath);
        return View();
    }
}

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This setup ensures that the IronPdfService is created and managed by the Microsoft Extensions Dependency Injection container. You can effortlessly substitute the default PDF generation service by offering an alternative implementation for the IPdfService interface, all without altering the consuming code.

Screenshot of the PDF File

Conclusion

Microsoft.Extensions.DependencyInjection is a powerful tool in .NET 6 for implementing dependency injection, which promotes loose coupling and enhances testability in applications. By integrating IronPDF, a feature-rich C# library, developers can easily generate is available.