Migrating from .NET Framework to .NET Core: Tips and Best Practices

Whether you’re in the midst of learning .NET Core or already experienced with the .NET Framework, there may come a time when you need to migrate an existing .NET Framework application to .NET Core. This can be a daunting task, but with the right approach and guidance, it can be made manageable and even straightforward.

In this article, we’ll be looking at the steps involved in migrating from .NET Framework to .NET Core, along with some tips and best practices to ensure a smooth transition.

1. Understanding .NET Core
2. Identifying the Type of Application to Migrate
3. Preparing Your .NET Framework Application
4. Migrating the Code
5. Testing Your Application
6. Best Practices and Tips

Before we delve into the process of migration, it’s important to have a good understanding of .NET Core and its advantages over the .NET Framework. .NET Core is a cross-platform, high-performance, open-source framework for building modern, cloud-based, and internet-connected applications.

It’s worth noting that .NET Core includes ASP.NET Core and Entity Framework Core, making it suitable for a wide range of applications including web apps, microservices, and console applications.

The first step in migration is identifying the type of application you want to migrate. Not all .NET Framework applications can be directly migrated to .NET Core. Here’s a quick rundown:

• ASP.NET MVC and Web API Applications: These can be migrated to ASP.NET Core.
• WPF and Windows Forms Applications: As of .NET Core 3.0, these can be migrated to .NET Core, but some specific functionalities may still be missing.
• Web Forms Applications: These cannot be migrated to .NET Core, as ASP.NET Core doesn’t support Web Forms.

Before starting the migration, it’s essential to prepare your .NET Framework application. Here are some steps to follow:

• Update to Latest .NET Framework: Make sure your application is using the latest .NET Framework version. This ensures that you have the latest features, performance improvements, and bug fixes.
• Use the API Portability Analyzer: The .NET Portability Analyzer is a tool that analyzes your assemblies and provides a detailed report on .NET APIs that are not available in .NET Core.
• Decouple Your Application: If possible, try to decouple your application into smaller, more manageable projects. This can make the migration process easier and allows you to migrate one project at a time.

Once your application is prepared, you can start migrating the code:

1. Create a new .NET Core Project: Depending on the type of application you’re migrating, this could be an ASP.NET Core project, a .NET Core Console App, or a .NET Core Class Library.
2. Migrate your code: Move your code from your .NET Framework projects to the new .NET Core projects. Be mindful of APIs or libraries that aren’t supported in .NET Core.
3. Replace .NET Framework libraries: If you’re using .NET Framework libraries that aren’t supported in .NET Core, you

’ll need to find alternatives. For example, if you’re using Entity Framework, you can migrate to Entity Framework Core.

After migrating your code, make sure to thoroughly test your application. Automated tests can be very useful here, so consider setting up unit tests, integration tests, and end-to-end tests for your application.

• Migrate Incrementally: Instead of trying to migrate everything at once, consider migrating incrementally. This approach allows you to tackle issues one at a time and can make the process more manageable.
• Use .NET Standard Libraries: If you have class libraries that you want to use with both .NET Framework and .NET Core, consider converting them to .NET Standard. .NET Standard is a set of APIs that are guaranteed to be available on all .NET implementations.
• Get Familiar with the .NET CLI: The .NET Core Command Line Interface (CLI) is a powerful tool for building, running, and managing .NET Core applications.

Migrating from .NET Framework to .NET Core can be a significant task, but with these steps, tips, and best practices, you’ll be well on your way to running your applications on the modern, cross-platform, and high-performance .NET Core framework. Happy coding!