dotnet-skills Current release catalog-v2026.4.5.0
Skill page Legacy v1.0.0

Legacy ASP.NET

Maintain classic ASP.NET applications on .NET Framework, including Web Forms, older MVC, and legacy hosting patterns, while planning realistic modernization boundaries.

Trigger On

  • working in Web Forms, legacy MVC, or classic ASP.NET applications
  • reviewing old IIS-centric configuration and lifecycle behavior
  • planning migration toward ASP.NET Core without breaking core business flows

Workflow

  1. Treat classic ASP.NET as a distinct stack with different hosting, lifecycle, and configuration rules from ASP.NET Core.
  2. Stabilize behavior first: routing, session, auth, server controls, configuration transforms, and deployment assumptions.
  3. Plan modernization in seams: isolate domain and service logic, then move replaceable edges instead of rewriting the whole app at once.
  4. Use dotnet-wcf or dotnet-entity-framework6 when the legacy app depends on those subsystems rather than flattening them into generic web work.
  5. Be careful with guidance copied from ASP.NET Core because middleware, DI, and hosting assumptions do not transfer directly.
  6. Validate in an environment that resembles real IIS and configuration transforms.

Deliver

  • practical maintenance guidance for classic ASP.NET
  • stabilized legacy behavior and modernization seams
  • a migration path that avoids unnecessary risk

Validate

  • classic and Core guidance are not mixed
  • legacy runtime assumptions are preserved deliberately
  • migration steps are incremental and testable

References

  • Migration Paths: strategies for migrating from ASP.NET to ASP.NET Core, including incremental migration, strangler fig pattern, and component-specific guidance
  • Maintenance Patterns: stabilization and maintenance patterns for legacy ASP.NET code, including abstraction layers, testing seams, and deployment practices

Related skills

v1.0.0

Maintain or assess Workflow Foundation-based solutions on .NET Framework, especially where long-lived process logic or legacy designer artifacts still matter.

Legacy
dotnet skills install workflow-foundation
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