ModelMaker C# Edition: Best Practices and Real-World ExamplesModelMaker C# Edition is a code-generation tool designed to speed up the creation and maintenance of model layers in .NET applications. It helps generate classes, interfaces, validation, mapping, and other boilerplate so developers can focus on business logic. This article covers best practices for using ModelMaker C# Edition, common pitfalls to avoid, and several real-world examples illustrating effective usage patterns.
Why use ModelMaker C# Edition?
- It reduces repetitive coding by generating consistent model classes and related artifacts.
- Improves maintainability through centralized templates and conventions.
- Integrates with typical .NET workflows (projects, build steps, source control).
- Encourages patterns like separation of concerns, DTOs, and mapping strategies.
Best Practices
1. Define a clear model strategy first
Before generating code, decide how models will be used:
- Will models be domain entities, DTOs for APIs, view models for MVVM, or a mix?
- Which models need validation, change tracking, or mapping?
- How will persistence concerns (EF Core, Dapper) be handled?
Keeping a strategy prevents generating unnecessary code and reduces later refactors.
2. Keep templates versioned and in source control
Store your ModelMaker templates and configuration alongside your code repository. This ensures:
- Reproducible generation across machines and CI.
- Easier review and evolution of templates.
- Ability to rollback template changes that introduce bugs.
3. Use partial classes and separation of generated vs. custom code
ModelMaker typically produces complete classes. Prefer generating partial classes so you can:
- Put generated code in one file and hand-written extensions in another.
- Re-generate safely without overwriting custom logic.
Example file layout:
- Models/Generated/Customer.generated.cs
- Models/Extensions/Customer.cs
4. Generate interfaces for testability
Generate interfaces (e.g., ICustomer) for models or service contracts where appropriate. This simplifies unit testing and lets you swap implementations.
5. Integrate generation into CI and developer workflows
Automate model generation as part of the build pipeline:
- Run generation locally via pre-build scripts or IDE tasks.
- Run generation in CI to ensure generated code is up-to-date.
- Fail the build if generated code is out of sync with committed templates.
6. Favor composition over inheritance in generated artifacts
Templates can produce base classes or mixins. Prefer composition (e.g., using injected services for validation/mapping) to reduce coupling and improve reuse.
7. Keep generated code minimal and explicit
Generate only what you need. Over-generating (deep validation hierarchies, unneeded interfaces) increases complexity. Configure templates to produce concise, readable code.
8. Use mapping layers instead of exposing persistence models
When using EF Core or other ORMs, avoid leaking persistence entities directly to the UI/API. Use generated DTOs and mapping code (AutoMapper, Mapster, or generated mappers) to decouple layers.
9. Document generated contracts
Include XML documentation on generated members where useful. That makes consuming the models in IDEs more pleasant and self-documenting.
10. Handle nullable reference types and annotations correctly
Ensure templates are aware of the project’s nullable context and emit nullable annotations (?) appropriately. This avoids NRT warnings and improves API clarity.
Common Pitfalls & How to Avoid Them
- Over-reliance on generated code: Keep business rules in hand-written services; generated code should be structural.
- Committing generated files without source-of-truth templates: Always pair generated code with the templates that created it.
- Breaking custom code on regeneration: Use partials and avoid editing generated files.
- Ignoring performance implications: Generated equality, serialization, or change-tracking logic can have runtime costs—profile if concerned.
Real-World Examples
Example 1 — API DTOs and Mapping
Scenario: You have EF Core entities and need stable DTOs for a public API.
Approach:
- Use ModelMaker to generate DTO classes from a schema or entity contracts.
- Generate mapping code using Mapster or AutoMapper profiles, or generate direct mappers to avoid runtime reflection.
- Keep DTOs separate from EF entities; use mapping in controllers/services.
Code snippet (generated mapper pattern):
public static class CustomerMapper { public static CustomerDto ToDto(this Customer entity) => new CustomerDto { Id = entity.Id, Name = entity.Name, Email = entity.Email }; public static void UpdateEntity(this CustomerDto dto, Customer entity) { entity.Name = dto.Name; entity.Email = dto.Email; } } Example 2 — MVVM ViewModels with Validation
Scenario: WPF app needs view models with property change notifications and validation.
Approach:
- Generate ViewModel classes implementing INotifyPropertyChanged and IDataErrorInfo (or INotifyDataErrorInfo).
- Use partial classes for custom commands and business logic.
- Generate validation stubs for required fields and range checks.
Generated property pattern:
private string _name; public string Name { get => _name; set => SetProperty(ref _name, value); // SetProperty raises PropertyChanged } Example 3 — Multi-tenant Model Variants
Scenario: A SaaS product where models vary by tenant configuration.
Approach:
- Parameterize templates to emit tenant-specific properties or behaviors.
- Generate feature-flagged partial classes per tenant where necessary.
- Use a shared core generated model and tenant-specific extensions.
Example 4 — Legacy Database Modernization
Scenario: Migrating a legacy database schema to a modern domain model.
Approach:
- Reverse-engineer database tables into generated model scaffolding.
- Use templates to normalize naming, apply data annotations, and generate mapping to new domain models.
- Iteratively refine templates as domain understanding improves.
Example 5 — Event-Sourced Models
Scenario: Building an event-sourced domain where models are reconstructed from event streams.
Approach:
- Generate event classes and aggregator methods to apply events to domain state.
- Keep generated Apply(Event) methods minimal; implement complex business logic in hand-written methods.
- Generate tests alongside models to validate rehydration logic.
Template Design Tips
- Keep templates modular: smaller templates are easier to test and maintain.
- Provide sensible defaults but allow overrides via configuration files.
- Include sample unit tests generation for critical mapping/validation logic.
- Offer options for nullable handling, JSON serialization attributes, and data annotations.
Testing Generated Code
- Unit test generated mappers and validation logic.
- Use snapshot tests to detect unintended template changes.
- Run static analysis (Roslyn analyzers, StyleCop) on generated code and exclude rules that produce noise, or tune templates to satisfy analyzers.
Performance Considerations
- Avoid heavy generated reflection-based code at runtime; prefer source-generated mappers where possible.
- Minimize creation of large object graphs during mapping—use streaming or projection when querying databases.
- Profile serialization and equality implementations added by templates.
Security and Privacy
- Ensure generated DTOs don’t accidentally include sensitive fields (passwords, PII). Use templates to explicitly exclude or redact fields.
- When generating serialization attributes, prefer explicit inclusion (opt-in) rather than opt-out.
Migration & Evolution Strategy
- When changing templates, version them and create migration scripts to update existing generated files safely.
- Use deprecation attributes in generated code to signal upcoming changes to consumers.
- Maintain backward-compatible DTOs where public APIs are involved; introduce new versions rather than breaking changes.
Conclusion
ModelMaker C# Edition can significantly speed development and improve consistency when used with clear strategies and disciplined template management. Favor small, well-versioned templates, separate generated and custom code, integrate generation into CI, and generate only what’s necessary. The real-world examples above show common patterns for APIs, MVVM, multi-tenant systems, legacy migrations, and event sourcing. With thoughtful use, ModelMaker becomes a force-multiplier rather than a maintenance burden.
Leave a Reply