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Modernizing WebForms: Migrating to .NET for Better Performance

Adam Chałaszczyk Head of .NET Engineering
6 min read
04.02.2025

Evolution of Microsoft Web Solutions: From ASP to .NET and Beyond

Web development is constantly evolving. In line with the dynamic evolution of technologies, Microsoft has consistently aimed to follow the latest trends and introduce new approaches. In the mid-1990s, it began with Active Server Pages (ASP) and server-side rendering, enabling the creation of dynamic web pages. This evolved into ASP.NET in early 2000s, offering a powerful and enterprise-ready environment for web applications. ASP .NET WebForms was designed to simulate the behavior of WinForms applications but without requiring installation on local PCs.

Over time, Microsoft introduced technologies, such as Silverlight and ASP.NET MVC. Today, .NET and ASP.NET Core offer modern solutions while retaining the MVC option.

Many business applications have migrated from traditional Windows applications to what was then the modern WebForms approach. However, keeping up with rapidly changing technology trends is challenging. As a result, WebForms-based solutions are still encountered but are now considered outdated, difficult to maintain, and slow.

Challenges of WebForms: Performance, Maintenance, and Compatibility Issues

WebForms was designed to mirror the lifecycle of Windows applications, making it easier for software engineers migrating from WinForms to adopt this approach. However, this solution, revolutionary at that time, has multiple  drawbacks and limitations:

  1. Performance issues
    The reliance on server-side rendering and multiple postbacks/callbacks (especially with AJAX approach) leads to slow response times.
  2. Limited and complicated control over HTML
    Server-side rendering requires HTML manipulation to be done either server-side or via JavaScript, which can be complex and restrictive.
  3. Challenging user experience
    Achieving the level of user experience provided by modern web development approaches offer is difficult.
  4. State management
    The use of ViewState can lead to larger responses and increased server requests.
  5. Limited compatibility with open-source frameworks
    Integrating with the ever-growing market of external open-source plugins is problematic and often not possible.
  6. Server dependency
    The platform is tied to Microsoft servers, making it unsuitable for deployment on modern Linux containers.
  7. Shrinking developer pool
    The number developers familiar with WebForms is declining, driving up maintenance costs.
  8. .NET Core incompatibility
    ASP.NET WebForms is not supported by the latest .NET editions.
  9. Testing challenges
    Automated testing is complicated due to dynamically generated IDs and complex request structures.

Effective Approaches for Migrating from WebForms to Modern Web Architectures

Transforming an ASP.NET WebForms application into a modern architecture involves several steps and considerations, with the goal of achieving a more modular, scalable, and maintainable design. Remember, the best approach depends on specific project requirements, the complexity of the existing codebase, and resource availability. In some cases, rewriting the application from scratch might be more feasible than migrating the existing code, especially if the application is large, complex, or heavily tied to WebForms-specific features.

Based on those factors, several options can be considered.

Rewrite UI and Retain Logic

Show me how your logic is set up, and I’ll help figure out a solution. Depending on where and how your code is written, we might need to try a few different techniques to fix things. WebForms often mixes the business stuff with the user interface parts, and it’s not always easy to separate them without a significant reworking.

 We can still can consider at least two scenarios:

  • If your logic is in application layers (application code):
    • Try to keep as much as possible of the existing logic without migrating to the latest .NET Framework.
    • Use the existing logic to set up an API layer.
    • Pick a new framework for the UI, maybe a Single Page Application (SPA) approach like Angular or React.
  • If your logic is in stored procedures/functions:
    • Keep all database layer as it is, including stored procedures and structures (small tweaks might be needed)
    • Either migrate existing code layers or create new ones, drawing from the business logic in the stored procedures.
    • Choose a new UI framework, such as Angular, React, Vue.js.

Either way, you’ll end up with better user experience and performance. Plus, these steps will allow you to start moving towards the latest .NET version and containerization.

Change UI and Migrate Logic to a Modern Framework

In this approach, we aim to enhance the solution by upgrading to the latest .NET components available and developing a new user interface using a technology of your choice. This results in a fully modernized solution, ready for cloud deployment in containerized environments like Kubernetes. While this path is more demanding in terms of time and resources, it is advantageous compared to a complete rewrite, as it allows you to retain most of the existing logic.

Slowly Modernize UI to Improve UX and Performance

If your solution is large and you’re not ready for a full makeover, it’s still a good idea to avoid creating new features in the old WebForms way. Here’s a strategy you might consider:

  • Only perform the necessary maintenance and bug fixes on the old code. Avoid creating new screens or features using the old WebForms approach.
  • Set up an API layer that can support a new UI.
  • Begin building new screens with Angular (or another UI framework you prefer) and connect them to the API, which will use your existing logic.
  • Start using the Web Components approach, like Angular elements. This way, you can update your UI bit by bit, feature by feature. Plus, you’ll build a set of reusable controls for any future re-platforming.
  • Keep improving and separating your logic to prepare for future updates.

This approach ensures you won’t be adding to your technical debt and helps you move away from the challenge of finding WebForms developers. You can begin implementing this strategy with the next round of updates or new business requirements.

Build Hybrid Solutions

If a fully custom app is no longer necessary, or if you want to incorporate market-available solutions into your app, a hybrid approach could work well. For instance, if you need content management features, think about integrating with a headless CMS. This allows you to maintain full control over your user experience, keep as much of your existing logic as needed, and avoid building a CMS from scratch.

By going hybrid, you can shift some features or functionalities to specialized services or apps, ideally by just leveraging their APIs. This lets you focus on what makes your solution unique, without reinventing the wheel for features that are already available in the market.

If you’re leaning toward a hybrid solution, Microsoft’s Power Platform is also worth considering. If your application doesn’t necessarily have to be web-based, you could use canvas or model-driven apps on Power Platform to plug into the data and logic from your old WebForms application. This approach can also provide an easy pathway to integrate with Microsoft Teams and its ecosystem.

Leverage Low Code

When considering updating your application, low-code platforms like Outsystems or Microsoft Power Platform can be a good option to speed up development and migration. These platforms enable rapid creation of new features. However, they usually require adapting to their specific ecosystems, which can pose challenges when it comes to integrating existing logic. Directly reusing old code often isn’t possible, meaning you might need to rebuild some parts of your application within the new platform.

Key Takeaways for Modernizing WebForms and Migrating to .NET Solutions

Microsoft’s web development technologies have continuously evolved, with ASP and ASP.NET being significant milestones. However, WebForms, despite its initial innovation, now faces various challenges, including performance issues and limited modern integration capabilities. To modernize, strategies range from partial UI rewrites while maintaining logic to adopting hybrid or low-code solutions, each offering different benefits and fitting various business needs and technical constraints.

By choosing the right approach for your application, you can ensure it remains scalable, efficient, and aligned with modern development standards, paving the way for future innovation and competitiveness in an ever-changing digital landscape.

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