VB6 to C# migration: automated vs manual conversion

Abto Software
4 min readJan 24, 2024
VB6 to C# migration: automated vs manual conversion, by Abto Software

This post is a quick overview of an Abto Software blog article.

As modern computer technology evolves dynamically, business modernization is becoming more important. Legacy applications — typically utilized by organizations in the healthcare segment, government, construction — are presenting major roadblocks sensibly deteriorating business competitiveness, customer satisfaction, everyday performance, and sustainability.

That’s why business leaders across industries are approaching:

VB6 migration: technology dive-in

Visual Basic 6 (VB6), initially introduced in the late 1990s, has had notable importance and left lasting impact. But, however, over time, various factors have prompted business leaders towards exploring better alternatives. Visual Basic 6 support was stopped, which means users sticking to it don’t receive regular updates and patches. The absence of active mainline support poses multiple considerable challenges — security vulnerabilities, compatibility issues, limited flexibility and scalability, performance regression, and more.

Embracing modernization does not only demonstrate a commitment to innovation and progress but facilitates brand perception and reputation, improves customer trust, enhances employee morale, and more.

VB6 to C# migration, technology dive-in, by Abto Software

VB6 to C# migration — a trend worth following

If you’re still using VB6 applications, software modernization is about long-term justification and opportunities. Speaking about VB6 to C# conversion, legacy modernization and upgrade, especially considering today’s trends, is a future-proof strategy, and that for multiple good reasons.

These include:

  • Software longevity and support
  • Talent pool
  • Improved security
  • Enhanced integration
  • Business performance and scalability
  • User satisfaction and loyalty
VB6 to C# migration, the reasons for modernization, by Abto Software

Automated migration

Automated migration is used to convert programming languages or platforms by utilizing specialized programs. In the narrow context of handling VB6 to C# migration, by using such tools, software developers can translate legacy code directly into C# code without completely rewriting applications.

The process in a step-by-step breakdown:

  1. Initial assessment and inventory — code analysis and cataloging of forms, modules, classes, and other important components
  2. Initial conversion — the use of the migration tool to translate VB6 constructs to their C# counterparts and convert UI components to their .NET equivalents
  3. Careful review — migration tools generate logs, error messages, and warning, which must be reviewed to understand potential issues
  4. Manual intervention and refinement — rewriting certain “problematic” sections, finding appropriate .NET replacements, handling functionalities, which are more complex, and more
  5. Thorough testing
  6. Additional optimization and refactoring
  7. Application deployment
  8. Post-migration support and maintenance

Manual migration

Manual migration means moving legacy code from one, outdated technology to another without utilizing specialized programs or scripts, but rather manually transferring or rewriting outdated applications and data. To handle VB6 to C# migration without utilizing such tools, software developers must have nuanced expertise in both the original programming language and the target technology.

But how should you choose between those approaches?

VB6 and C# comparison

Let’s look more closely at the differences between VB6 and C# programming:

VB6 characteristics

  • Nature, paradigm — procedural programming, limited object-oriented features
  • Development environment — Visual Basic 6.0 IDE
  • Supported platforms — Windows desktop
  • Runtime environment — VB6 Runtime
  • Syntax — English-like syntax
  • Memory — manual memory management, automatic aspects (limited)
  • Library & framework — VBA library, ActiveX controls
  • Community and support — legacy support

C# characteristics

  • Nature, paradigm — object-oriented programming, supports functional concepts
  • Development environment — Visual Studio, powerful debugging & profiling, management tools
  • Supported platforms — Windows desktop, web, mobile, multiple platforms (.NET Core, .NET 5/6+)
  • Runtime environment — .NET framework, .NET Core, .NET 5/6+
  • Syntax — C-style syntax
  • Memory — garbage collection
  • Library & framework — .NET libraries, NuGet package manager for third-party libraries
  • Community and support — large, active community, Microsoft support (official)

Choosing between automated and manual migration

In the paragraphs below, we compared automated and manual conversion in brief:

Automated migration

  • Cost — generally lower
  • Time — faster conversion
  • Migration accuracy — good for standard code
  • Code quality — very variable
  • Customization — limited to tool’s capabilities
  • Modernization — limited to tool’s capabilities
  • Dependency handling — can attempt automatic conversion or offer .net equivalents
  • Error handling — manual review
  • Integration — limited to tool’s capabilities
  • Maintenance — might require manual tweaks after conversion

Manual migration

  • Cost — typically higher because of developer hours
  • Time — slower conversion, as code is being rewritten and adapted manually
  • Migration accuracy — high, if approached correctly
  • Code quality — clean, idiomatic, and optimized
  • Customization — highly flexible and adaptable
  • Modernization — provides opportunity to refactor and modernize
  • Dependency handling — deliberate decisions on redesign or replacement
  • Error handling — manual review
  • Integration — allows integration with modern .net technologies
  • Maintenance — better structured for simpler future maintenance

Summing up

If you start noticing:

  • Operational disruptions, including downtimes, unexplained errors, or crashes
  • Customer feedback about outdated user interfaces, lacking features, or similar customer issues
  • Security vulnerabilities that can’t be addressed due to the nature of the programming language
  • Compatibility issues with newer operating systems, software or hardware components, or databases
  • Performance shortfalls when handling increased loads
  • Integration challenges when introducing modern platforms, web services, or other

You know it’s time for modernization.

Abto Software, having the needed knowledge and expertise, assists partners by covering VB6 to C# migration. From evaluating legacy programs to performing project planning, execution, validation, as well as maintenance, our company smoothly converts outdated applications to drive business performance.

Contact us for investigation, code migration and finalization, optimization, deployment, and support.

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Abto Software

We empower customers business with innovative software by applying science, R&D, and own IP at abtosoftware.com