Overview

In the rapidly changing landscape of web development, frameworks and technologies are continuously evolving. ASP.NET MVC 5 was once a cornerstone of Microsoft's web development stack, providing a powerful model-view-controller (MVC) pattern that developers worldwide utilized to build dynamic websites and applications. However, with the advent of ASP.NET Core, the landscape shifted, leaving some developers feeling lost as to what happened to ASP.NET MVC 5.

Transition to ASP.NET Core

ASP.NET Core: A Unified Platform

ASP.NET Core, launched as a modular, high-performance framework, represented a significant shift from its predecessors, including ASP.NET MVC 5. The primary goal of ASP.NET Core was to provide a unified development model for building web applications, cloud services, and microservices.

Here's how ASP.NET Core differs from ASP.NET MVC 5:

1. Cross-platform Capabilities: ASP.NET Core is designed to work across Windows, macOS, and Linux, whereas ASP.NET MVC 5 was limited to Windows.
2. Performance and Modularity: ASP.NET Core provides better performance due to its lightweight and modular architecture. Developers can include only the necessary components, reducing the overall application footprint.
3. Unified Development Model: ASP.NET Core merged the MVC and Web API frameworks, providing a single platform for building APIs and web applications.

Why ASP.NET Core?

• Open Source: ASP.NET Core is open-source, helping developers contribute to its growth and adapt it to their needs. This shift to open-source development allowed Microsoft to tap into a broader community of developers.
• Entity Framework Core: The introduction of Entity Framework Core, a lightweight and extensible version of Entity Framework 6, improved data access patterns and integrated seamlessly with ASP.NET Core applications.
• Dependency Injection: ASP.NET Core comes with built-in dependency injection, making applications more testable and maintainable.

Technical Differences

Below is a table summarizing the key technical differences between ASP.NET MVC 5 and ASP.NET Core:

Migrating from ASP.NET MVC 5 to ASP.NET Core

Key Migration Steps

Migrating an existing project from ASP.NET MVC 5 to ASP.NET Core can seem daunting due to several architectural changes. Below are essential steps to consider:

1. Project File Upgrade: ASP.NET Core uses .csproj files, which are simpler and more human-readable than the .csproj of older ASP.NET projects.
2. Configuration Transition: Move from web.config to appsettings.json and environment-based configurations.
3. Handling of NuGet Packages: ASP.NET Core relies more heavily on NuGet packages for components that were once included by default in the .NET Framework.
4. Middleware over Modules: Replace HTTP modules and handlers with middleware in the ASP.NET Core pipeline.
5. Data Access Layer: Upgrade from Entity Framework 6 to Entity Framework Core to address compatibility issues and take advantage of new features.
6. Authentication and Authorization: Update authentication mechanisms to utilize ASP.NET Core Identity and the new patterns for claims-based security.

Example

Here is an example showing the differences in handling a middleware component in both frameworks.

ASP.NET MVC 5: