Action Filters are a feature in ASP.NET MVC that allow developers to inject logic before or after an action method is executed. They can be used to modify the behavior of an action method, such as by caching its result, logging its execution, or validating input data.

The role of Action Filters in ASP.NET MVC can be summarized as follows:

Intercepting requests: Action Filters can intercept requests before they are processed by an action method, allowing developers to perform additional processing or validation on the request data.

Modifying action behavior: Action Filters can modify the behavior of an action method, such as by caching its result, logging its execution, or redirecting the user to a different URL.

Providing cross-cutting concerns: Action Filters can be used to provide cross-cutting concerns that apply to multiple action methods, such as authorization, exception handling, or performance monitoring.

Separation of concerns: Action Filters help to separate concerns by allowing developers to encapsulate behavior that is not specific to an action method or a controller in a reusable component.

Action Filters can be defined at the action method level, the controller level, or globally for the entire application. They can be synchronous or asynchronous, and can be chained together to create more complex behavior.

In summary, Action Filters provide a powerful mechanism for intercepting requests and modifying action behavior in ASP.NET MVC. They enable developers to provide cross-cutting concerns and separate concerns, improving the maintainability and scalability of their applications.