Migrating From ASP .NET To .NET Core: Everything You Need To Know


April 6, 2020


June 21st, 2023

ASPNET_to_NETCore_migrationMicrosoft is continuously investing in its technology stack, enabling developers to build secure and enhanced software products that empower businesses to meet ever-changing customers’ needs. Microsoft’s flagship cloud services and business intelligence products are showing no decline in the number of users, while development platforms like .Net keep growing at pace with modern features and enhancements.

.Net framework was launched in 2001 and even after 19 years, it is the first choice of developers to build scalable, secure, and powerful business applications. ASP .Net Core, a widely popular open-source web framework is a complete rewrite of ASP.NET MVC and ASP.NET Web API with advanced features.

Many versions of the .Net framework are becoming obsolete and Microsoft will no longer support those in the upcoming time. With this, migration to an upgraded platform seems necessary to leverage modern features in your app.

.Net platform powers a huge number of .NET development services and that is one of the reasons it will still be continued in the coming time. .Net Core is indeed the future and as per the latest news, Microsoft is planning to remove Core and release .Net 5 – a unified and only one .NET framework in the future.

More and more .Net applications are migrating to .Net Core to build ultramodern solutions. Here, in this post, we will talk about every possible reason to migrate to .Net Core including business benefits, tips for smoother migration, and reasons.

Good Read: .NET Framework vs .NET Core

ASP .Net To .Net Core Migration : Key Reasons Explained

  • Cross-Platform Support

ASP.NET Core development offers cross-platform support which was not possible in previous .Net versions. Developers can build apps for Windows, Mac, and Linux platforms and it can be used to build cloud and IoT applications with modern architecture.

  • Better Performance And Scalability

This framework is enhanced to offer better performance, speed, and efficiency. With modern architectural concepts like containerization and microservices, scalability is not a problem as .Net Core is designed to manage apps built with hundreds of microservices or technology like Docker.

  • Faster Time-To-Market And Secure

Modular architecture, Razor Pages, powerful UI components, regular updates, wider community support, secure processes, easy integration of client-side frameworks, lightweight, cloud-ready, and built-in dependency injection – these make development faster and allow businesses to leverage continuous development and deployments.

How To Migrate From ASP .Net To ASP .Net Core?

Here are some basic steps of .NET Core migration:

  • Retarget all projects you wish to port to target .NET framework 4.7.2 or higher. When .Net Core doesn’t support a specific API, this step makes sure that you can use alternative APIs for .Net Framework-specific targets.
  • Use .Net Portability Analyzer. This tool analyzes assemblies and tells if they’re portable to .Net Core.
.Net Portability Analyzer
Credit: Microsoft
  • Install the .NET API analyzer to identify APIs that throw PlatformNotSupportedException on some platforms and identify other potential compatibility issues.
NET API analyzer
Credit: Microsoft
  • Convert all of your packages.config dependencies to the PackageReference format with the conversion tool as packages.config doesn’t work on .NET Core.
  • .Net Core uses a simplified project file format than the .NET framework so you need to create new projects for .NET Core and copy source files or convert your existing files with a tool.
  • It’s advisable to port your test code: Porting is one such significant change that can cause damage if things don’t go well. It is highly recommended to port your test project and run/test the code.

Some Other Significant Things You Need To Take Care While .NET Core Migration:

  • The .csproj file format is now simplified in ASP .Net Core. This file can be edited without unloading it in Visual Studio.
  • .Net Core offers the flexibility of targeting .Net Core, .Net Framework, or both.
  • In ASP .Net Core, the entry point to an app is Startup and you don’t have a dependency on Global.asax. Startup must have a Configure method. You will require adding the necessary middleware to the pipeline in Configure.
Image Source: tutorialsteacher.com
  • Dependency Injection is a useful concept in software architecture where one object supplies the dependencies of another project. This is very important when building large, loosely coupled, and scalable applications. DI helps in such scenario and now it’s a native component of dot net core architecture.
  • Multi-value cookies are not supported in .Net Core. You can create one cookie per value.
  • There is no application life cycle in ASP .Net Core and also there is no order in which responses are processed by middleware. It is different from the order used by modules. Here is how you can do it:

Migrating HTTP handlers and modules to ASP .NET Core middleware.

Useful Tips For Smoother .NET To .NET Core Migration

Any framework migration will require pre-planning, continuous monitoring, network readiness, code safety, and provisions to fix issues if they arrive.
For smoother migration,

  • You can try smaller modules/projects instead of moving a whole codebase to the .Net Core.
  • dotnet try-convert tool helps you convert your project to the .Net Core but it is not a guaranteed solution and it may cause subtle changes in behavior. You can use it as a starting point to automate basic things.
  • Identify the “base” of the library. It could be the data models or classes and methods that are essential. Copy the base into a new .NET Core project. Make any changes needed to compile the code. Copy another layer of code and repeat it.
  • .NET Core developers can also use the open-source code editor of Microsoft called Visual Studio (VS) code which is supported across all leading OS systems -Windows, Linux, and macOS.

More and more companies are migrating to .Net core for better performance, speed, flexibility, modularity, and easy deployment.

Though, there are several drawbacks of the .Net Core, such as:

  • Windows Forms and WPF applications are not supported in .Net Core.
  • .Net Core does not support WCF.
  • ASP.NET Web Pages and ASP.NET WebForms are not there in .Net Core.
  • Partial support for VB .NET and F#.
  • There are no plans to bring WF/WCF+WF/WCF Data Services to .NET Core yet.
  • 3rd-party library support and some features are missing in .NET Core.
  • You need to access Windows-specific APIs. If your application needs to work with the Windows Registry, WMI, or other Windows-specific APIs, it won’t work with .NET Core.

The process of migrating comes with a risk. And that’s the reason it should be carried out with utmost care and attention. The open-source developers’ community of .Net offers consistent support and ideas/suggestions/tips to achieve higher performance. Also, Microsoft is making frequent updates and help developers to stay up-to-date with comprehensive guides and documentation. As Microsoft is working on .Net 5 to make it a unified platform, we all expect a better outcome, speed, flexibility, and suitability of the .Net framework as a powerful and modern development platform.

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