rc-migration-tests/vb-migration/VB-CS-migration-guide.md

Comprehensive VB.NET to C# Migration Guide

Overview

This guide outlines the process for migrating from VB.NET Framework to C# .NET 8, emphasizing a two-phase approach and leveraging AI tools for optimal results.

Phase 0: Prerequisites and Planning

Critical Prerequisites

1. Test Coverage

   • Minimum 80% code coverage with unit tests
   • Integration tests for critical workflows
   • End-to-end tests for main user journeys
   • Performance benchmarks

   AI Enhancement: Use Claude to analyze code and generate comprehensive test cases, identifying potential edge cases and critical test scenarios.

2. Code Quality Baseline

   • Static code analysis
   • Remove deprecated API usage
   • Clean up dependencies
   • Fix compiler warnings

   AI Enhancement: Leverage Windsurf for security checks and best practice recommendations during the cleanup phase.

3. Documentation

   • API documentation
   • Business rules
   • System architecture
   • Integration points

   AI Enhancement: Use Claude to generate technical documentation and API references from existing code.

Phase 1: Framework Migration (VB.NET to .NET 8)

Step 1: Environment Setup

1. Install required tools:

   dotnet tool install -g upgrade-assistant
   dotnet tool install -g ICSharpCode.CodeConverter.Cli
   

2. Set up version control and backup
3. Create separate environments for testing

Step 2: Initial Analysis

1. Run .NET Upgrade Assistant analysis:

   upgrade-assistant analyze your-solution.sln
   

   AI Enhancement: Use Claude to:

   • Analyze framework-specific dependencies
   • Identify outdated patterns
   • Suggest modern alternatives
   • Review upgrade-assistant recommendations

2. Document dependencies and framework-specific code

   AI Enhancement: Use Windsurf to:

   • Identify security implications
   • Suggest secure alternatives
   • Review configuration settings

Step 3: Framework Migration Execution

1. Start with smallest, least dependent modules
2. Run upgrade assistant:

   upgrade-assistant upgrade your-solution.sln
   

3. Update package references
4. Fix compatibility issues

Phase 2: Language Migration (VB.NET to C#)

Step 1: Code Conversion

1. Use ICSharpCode.CodeConverter:

   code-converter convert-project <source-project-file> -l VB2CS -t ConvertedProject
   

   AI Enhancement: Use Claude to:

   • Review converted code
   • Identify potential bugs
   • Suggest modern C# features
   • Optimize code patterns

Step 2: Post-Conversion Tasks

1. Code Review

   • Review generated C# code
   • Apply C# best practices
   • Optimize for .NET 8 features

   AI Enhancement: Use Windsurf for:

   • Security validation
   • Performance optimization
   • Best practice compliance

2. Testing

   • Run all test suites
   • Perform integration testing
   • Validate business logic

   AI Enhancement: Use Claude to:

   • Generate additional test cases
   • Identify potential edge cases
   • Suggest performance improvements

Best Practices

Migration Process

1. Follow the two-phase approach strictly
2. Start with smaller modules
3. Maintain comprehensive testing
4. Document all changes
5. Use version control effectively

AI Tool Usage

1. Claude

   • Code analysis and review
   • Pattern modernization
   • Documentation generation
   • Test case creation
   • Performance optimization

2. Windsurf

   • Security validation
   • Best practice enforcement
   • Pattern suggestions
   • Configuration review

Risk Mitigation

1. Create technical risk register
2. Implement fallback procedures
3. Maintain parallel environments
4. Document all decisions
5. Regular stakeholder communication

Common Issues and Solutions

Framework Migration

1. Dependency Conflicts

   • Solution: Use NuGet package manager to resolve
   • AI Enhancement: Use Claude to analyze dependency trees

2. API Compatibility

   • Solution: Use compatibility analyzer
   • AI Enhancement: Use Windsurf to suggest secure alternatives

Language Migration

1. Syntax Differences

   • Solution: Review converter output carefully
   • AI Enhancement: Use Claude to identify and fix conversion issues

2. Performance Issues

   • Solution: Profile and optimize
   • AI Enhancement: Use Windsurf for performance recommendations

Conclusion

Success depends on:

• Following the correct migration sequence
• Leveraging AI tools effectively
• Maintaining thorough testing
• Documenting all changes
• Regular validation and review

Remember to start with a pilot project to validate the process before full migration.