Why should you care?

These patterns appear in enterprise .NET jobs and senior interviews.

See it live — copy this example

Create an MVC project (dotnet new mvc), add the code, and run dotnet run.

// SOLID Principles — separate folders:
// ShopNest.Domain / Application / Infrastructure / ShopNest.Mvc

Run Example »

This lesson uses terminal or setup steps. Run commands on your computer — the live editor appears on coding lessons.

What happened?

• Study the example line by line.
• Each part connects to SOLID Principles in MVC.
• Edit one line, save, and run dotnet run to see what changes.

Try it yourself

1. Sketch which layer owns this concern.
2. Move one piece of logic out of the controller.
3. Run a manual check to confirm behavior unchanged.
4. Change text or labels in the example and run again — watch the browser update.
5. Break the code on purpose (remove a semicolon), read the error message, then fix it.

Remember

You learned what SOLID Principles in MVC is and when to use it. Practice by changing the example yourself. Explain it in your own words before moving on.