Overview:

The Proxy Pattern in C# is like having a trusty code bodyguard—shielding and controlling access to your precious objects. Let's unveil this stealthy coding strategy:

Implementation in C#:

In C#, the Proxy Pattern involves creating a surrogate or placeholder for another object to control access or perform additional actions. Imagine a virtual proxy for loading images:

// Subject interface
public interface IImage
{
    void Display();
}

// Real Subject
public class RealImage : IImage
{
    private readonly string filename;

    public RealImage(string filename)
    {
        this.filename = filename;
        LoadImageFromDisk();
    }

    private void LoadImageFromDisk()
    {
        Console.WriteLine($"Loading image: {filename}");
    }

    public void Display()
    {
        Console.WriteLine($"Displaying image: {filename}");
    }
}

// Proxy
public class ImageProxy : IImage
{
    private RealImage realImage;
    private readonly string filename;

    public ImageProxy(string filename)
    {
        this.filename = filename;
    }

    public void Display()
    {
        if (realImage == null)
        {
            realImage = new RealImage(filename);
        }
        realImage.Display();
    }
}

Pros:

1. Access Control: Controls access to the real object, adding a layer of security.

2. Lazy Loading: Delays the creation and initialization of the real object until needed, improving performance.

3. Additional Functionality: Allows adding additional behavior or checks before delegating to the real object.

Cons:

1. Increased Complexity: Introducing proxies may increase initial code complexity.

2. Potential Overhead: Depending on the scenario, proxies may introduce performance overhead.

When to Use and When Not:

• Use: When you need to control access to an object, perform lazy loading, or add additional functionality transparently.

• Avoid: In scenarios where direct access to the real object is essential, or when the overhead of using proxies outweighs the benefits.

Usage in .NET Core Framework:

The Proxy Pattern is subtly present in the .NET Core framework, especially in scenarios where transparent access control or lazy loading is beneficial. For example, the Entity Framework utilizes proxy objects for lazy loading of related entities, providing a seamless and efficient data retrieval experience.

Real-Life Example:

Consider a scenario where you have a resource-intensive operation, like loading large images. Using a proxy, you can control access to the real image, ensuring it's loaded only when necessary:

// Usage
var imageProxy = new ImageProxy("high_resolution_image.jpg");

// Client code
imageProxy.Display();

Here, the ImageProxy ensures that the real image is loaded only when the Display method is called, preventing unnecessary resource consumption.

In conclusion, the Proxy Pattern in C# is your code's sneaky sidekick—shielding and controlling access with finesse. While providing access control and lazy loading benefits, developers should weigh the potential complexity and overhead when deciding to employ proxies. Its subtle presence in the .NET Core framework showcases its relevance in real-world scenarios where secure and controlled object access is paramount, turning coding challenges into a stealthy and secure operation.