OnResultExecuted

OnResultExecuted is a method in ASP.NET MVC and ASP.NET Core that serves as a filter that can be executed after the result of an action method has been executed. This means it runs after the action has completed and the result (such as a ViewResult, JsonResult, etc.) has been processed by the framework, but before the response is sent back to the client.

Filters in ASP.NET MVC and Core allow developers to inject custom logic into various stages of the request pipeline. OnResultExecuted is specifically designed for post-execution logic related to the action result. Common use cases include modifying the response after the action result has been created, logging information about the result, or performing cleanup tasks. For example, a developer might use OnResultExecuted to add custom headers to the response, serialize a JSON result with specific formatting, or log the type of action result that was returned.

The OnResultExecuted method typically receives an instance of ResultExecutedContext. This context object provides access to information about the request, the action executed, and the result that was executed. Developers can inspect the result, access the response, and even modify it before it's sent to the client. It's important to note that OnResultExecuted is executed in the opposite order of OnResultExecuting for filters. This means that if multiple OnResultExecuted filters are registered, they will execute in reverse order of their registration.