Why in .Net Core IActionResult used not ActionResult?
In .NET Core, both ActionResult and IActionResult are used to return action results from controller methods. The key difference lies in the flexibility and compatibility that IActionResult offers. IActionResult is an interface that ActionResult implements. By using IActionResult, you can return any type that implements IActionResult, providing more options for returning results. This flexibility is crucial when working with different types of responses in a unified manner. Additionally, IActionResult allows for better testability and promotes cleaner, more modular code. Therefore, in .NET Core, IActionResult is preferred over ActionResult for its versatility and improved coding practices.
ActionResult is an abstract class in ASP.NET Core MVC, serving as a base for built-in result types. IActionResult is an interface defining a contract for action results, allowing for custom result types and greater code flexibility.
In ASP.NET Core, `IActionResult` is the contract for what an action method will return, allowing for flexibility in returning various result types like `ViewResult`, `JsonResult`, etc. `ActionResult` is the base class implementing this interface, providing common result types. Generally, it's preferred to return `IActionResult` for flexibility or specific result types derived from `ActionResult`.