ViewResult and ActionResult are two classes in ASP.NET MVC that are used to display the output of an action function.

1. Action-Result
For all action result kinds in ASP.NET MVC, ActionResult is the abstract base class. It serves as the foundation class for many result kinds, including JsonResult, ViewResult, and RedirectResult. Usually, you specify ActionResult as the return type when you define an action method in a controller.

As an illustration

public ActionResult MyAction()
{
    // Action logic here
    return View(); // Returns a ViewResult
}

2. ViewResult
ViewResult is a specific type of ActionResult that represents a result that renders a view. When you return a ViewResult from an action method, it means that the framework should render a view associated with the action.

For example

public ViewResult MyAction()
{
    // Action logic here
    return View(); // Returns a ViewResult
}

Key differences in nutshell

The following are the key differences in nutshell.

• ActionResult is more general: ActionResult is a more general type, and it can represent different types of results, not just views. It allows for flexibility in returning various result types.
• ViewResult is specific to views: ViewResult is a specific type derived from ActionResult and is used when you specifically want to return a view from an action method.
• ViewResult simplifies return type: If your action method is intended to return a view, using ViewResult directly can make your code more explicit and easier to understand.
• ActionResult provides more options: If your action method needs to return different types of results based on certain conditions, using ActionResult allows you to return different types of results (e.g., RedirectResult, JsonResult, etc.) from the same action.

Moreover, in practice, you can often use ViewResult directly when you know your action will always return a view. If you need more flexibility or want to return different types of results, using ActionResult allows for that versatility.