如何在IActionFilter MVC6中设置ViewBag？

using Microsoft.AspNetCore.Mvc.Filters;

public class CustomActionFilter : IActionFilter
{
    public void OnActionExecuting(ActionExecutingContext filterContext)
    {
        filterContext.Controller.ViewBag.Message = "Hello from CustomActionFilter!";
    }

    public void OnActionExecuted(ActionExecutedContext filterContext)
    {
        // Do something after the action method is executed
    }
}

[ServiceFilter(typeof(CustomActionFilter))]
public class HomeController : Controller
{
    // Controller actions
}

public class HomeController : Controller
{
    [ServiceFilter(typeof(CustomActionFilter))]
    public IActionResult Index()
    {
        // Action method logic
    }
}