For decades, Delphi has been the foundation of countless business apps. Its performance, rich component model, and rapid development capabilities created a generation of robust and reliable software. If your organization runs on a Delphi application, you understand its power. It contains years, or even decades, of refined business logic that is central to your operations.
But the technology world does not stand still. The advantages of the past become the limitations of the future very fast. You may now face:
- a shrinking pool of Delphi developers
- difficulties with integration into modern cloud services
- the strategic need to support web and mobile platforms
This realization leads to a decision: modernization. For many, the logical destination is C# and the .NET ecosystem. The prospect of such a migration can seem like a multi-year, high-risk project. However, this move is a strategic investment in your company's future.
With the right approach, the path from Delphi to C# will be a well-defined and efficient process, not a painful ordeal. Why even migrate to C#, and how to do it? All wrapped up below.
Why move to C# and .NET
The choice to migrate is not about abandoning a working system but about empowering it for the next chapter of growth. C# and the modern .NET platform offer many compelling advantages that address the challenges of legacy systems.
Read more:Rehost, Refactor, or Rebuild? 8 Ways to Modernize Legacy Systems
Thriving and unified ecosystem
The .NET of today is a far cry from its Windows-only origins. It is a unified, open-source platform that allows you to build high-performance applications for any environment: Windows, Linux, macOS, web, cloud, mobile, and even IoT.
This cohesive framework means your C# codebase can serve a web API, power a desktop application, and run in a cloud container, a level of flexibility that is difficult to achieve with older Delphi versions.
Unmatched performance and scalability
A common concern for Delphi developers is performance because Delphi apps are known for their speed. Fortunately, modern .NET is exceptionally fast. Through years of intense optimization, Microsoft has made .NET one of the highest-performing managed platforms available, rivaling the speed of native code.
Your migrated application will not only meet but often exceed its previous performance benchmarks, all while ready to scale in cloud environments.
Vast community and robust support
When you adopt C#, you gain the support of a massive global community. Stack Overflow and GitHub have millions of developers actively solving problems and sharing code. Plus, the NuGet package manager gives you access to hundreds of thousands of open-source libraries that can solve almost any problem, from complex data analysis to simple utility functions.
The vast ecosystem, backed by Microsoft’s clear and continuous investment in the platform, guarantees that .NET is a technology with a long and stable future.
Future-proof your business logic
Your core business rules are your most valuable asset. By migrating them from Delphi to C#, you extract them from a restrictive environment and place them into an adaptable one. Your intellectual property is safe and friendlier for onboarding of new developers.
With this setup, your business can take advantage of future technological shifts like AI integration, advanced analytics, and new cloud services.
Migration: manual vs. automated
Once the strategy is clear, the "How to do it?" becomes the central question. Broadly, there are two fundamental approaches to application modernization: a complete manual rewrite or an automated conversion.
Manual rewrite
The most traditional approach is to start from scratch. A team of developers takes the existing Delphi application as a specification and begins a complete rewrite in C#. While this seems to offer the promise of a perfect system, the reality is fraught with risk.
This process requires a deep reverse-engineering of decades of business logic, some of which may be poorly documented. It is incredibly time-consuming and can take years for complex apps. The costs are immense, too. Not just in developer salaries but also in project management overhead and business disruption.
During the long rewrite period, your legacy Delphi application still requires maintenance, forcing you to support two systems in parallel. Perhaps the greatest risk is functional regression: a high probability that subtle but critical business rules are missed or implemented incorrectly in the new system.
Automated pathway
An automated approach is a more pragmatic and efficient alternative. Instead of reinventing the wheel, you use sophisticated tools to translate the proven Delphi codebase into modern C# code. This is not a simple search-and-replace but a deep and contextual conversion that:
- preserves the application's functionality
- upgrades its technical foundation
Following this path, you can reduce the project timeline from years to months and eliminate the risk of misinterpreting business logic because it converts the logic that is already there. You also automate the most tedious and error-prone parts of the migration.
The whole process frees your development team to focus on high-value tasks: refining the new architecture, improving the user interface, and adding new features.
Automated solution: CodeWays
When we speak of automated migration, the capability of the tool is everything. A simple syntax converter is not enough. You need a solution that understands the nuances of both Delphi and C#. This is the purpose of CodeWays by Ispirer.
CodeWays works beyond syntax
CodeWays performs a comprehensive application transformation. It parses your Delphi project — including forms (.dfm), source code units (.pas), and project files (.dpr) — to build a complete model of your application. This is how it sets the stage for an intelligent, context-aware conversion.
Intelligent component mapping
The visual component library is at the heart of most Delphi applications. CodeWays addresses this head-on by mapping VCL components to their modern .NET equivalents.
For example, a TForm can become a Windows Forms Form, a TButton becomes a Button, and a TDBGrid can be mapped to a DataGridView. This process can also be customized to target other UI frameworks like WPF or web technologies.
Handling data access with precision
Delphi applications use various methods like the BDE, FireDAC, or ADO. CodeWays automatically converts these data access calls to the .NET standard, ADO.NET. It also transforms embedded SQL statements, adjusting for differences in SQL dialects between source and target databases (e.g., Oracle to SQL Server).
Complete architectural transformation
The most powerful feature of CodeWays is its ability to change the application's architecture. Do you need to move from a two-tier desktop application to a three-tier web application?
CodeWays can analyze your Delphi code and separate it, generating a C# backend project for the business logic and a separate frontend structure with web-friendly representations of your original forms.
Customization
No two Delphi applications are identical. They often use custom components or unique coding patterns. Our team can customize the CodeWays tool for each project. We add or modify conversion rules to handle your unique codebase for the highest possible level of automation.
Read more:How Ispirer Customization Powers High-Speed Application Migration
Planning your migration: checklist
A successful migration project, even an automated one, requires careful planning. Here is a checklist to guide your preparation.
1. Conduct a pre-migration audit
Before you begin, analyze your existing Delphi application. Use automated tools like Ispirer's free Metrics to get a clear inventory of your code: lines of code, number of forms, components used, and database dependencies. This assessment defines the project scope and provides a basis for accurate time and cost estimates.
2. Define your target architecture
Be clear about your goal. Are you aiming for a like-for-like C# desktop application to minimize user retraining? Or is this an opportunity to move to a modern web or cloud-native architecture? Your target will determine the specific conversion rules and project plan.
3. Gather the right team
Your project team should include members with deep knowledge of the Delphi application's business logic. They will be invaluable for testing and validation. You will also need C# developers to take ownership of the new codebase and drive future development.
4. Establish a robust testing strategy
While automation preserves logic, rigorous testing is still essential. Plan for unit tests, integration tests, and user acceptance testing to validate that the migrated application behaves exactly as expected.
5. Choose a migration partner, not just a tool
A successful outcome depends on expert support. Ensure your chosen solution comes with a dedicated team of engineers who can assist with tool configuration, handle complex conversion scenarios, and help you navigate the entire process.
Your future on a modern platform powered by C#
The need for agility, integration, and access to a wider talent pool makes the move to C# and .NET a clear strategic imperative. By choosing an automated path with a powerful and customizable tool like CodeWays, you remove the fear, risk, and prohibitive cost associated with a manual rewrite.
You can preserve the invaluable business logic you have built over decades and place it on a platform that will support your growth for decades to come.
