Creating an action filter attribute that bypasses the actual execution of the action and returns a value for it

Question

Can I create an ActionFilterAttribute that bypasses the actual execution of the action and returns a value for it?

Answer 1

You can, like this:

1) Redirects to some action and then return some value:

public class MyFilterAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        /*If something happens*/
        if (/*Condition*/)
        {
            /*You can use Redirect or RedirectToRoute*/
            filterContext.HttpContext.Response.Redirect("Redirecto to somewhere");
        }

        base.OnActionExecuting(filterContext);
    }
 }

2) Write some value direcly into the request and Ends it sending to the client:

public class MyFilterAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        /*If something happens*/
        if (/*Condition*/)
        {
            filterContext.HttpContext.Response.Write("some value here");
            filterContext.HttpContext.Response.End();
        }

        base.OnActionExecuting(filterContext);
    }
 }