Both ASP.NET MVC and WebForms are web application frameworks, with MVC gaining popularity for its code cleanliness, separation of concerns, and flexibility.

Key Differences

1. Request Handling

• WebForms: Uses a page controller model where a single page (web form) handles all tasks like request processing, UI rendering and event handling.
• MVC: Adopts the Front Controller pattern where the Controller is the entry point, directing requests to specific actions. Each action maps to a view, offering finer control.

2. Routing

• WebForms: Rely on URL mappings established in the <system.web> section of web.config.
• MVC: Employs a powerful attribute-based routing mechanism. Entities can be assigned their unique URLs based on URL templates.

3. State Management

• WebForms: Abstracts the HTTP stateless nature through mechanisms like ViewState, Session, and Control State.
• MVC: Uses a stateless approach, offering more transparency and control. Stateful actions are supported via Context objects or custom implementations.

4. HTML Generation

• WebForms: Features server controls that render HTML based on the server-side logic written in ASP.NET.
• MVC: Offers highly-lauded Razor syntax for a more structured generation of dynamic web content.

5. Testability

• WebForms: Is less testable due to event-driven architecture.
• MVC: Separation of concerns makes components easier to test in isolation, facilitating unit and integration testing.