How to either return JSON or RedirectToAction?

Question

I have an Action Method that I'd either like to return JSON from on one condition or redirect on another condition. I thought that I could do this by returning ActionResult from my method but doing this causes the error "not all code paths return a value"

Can anyone tell me what I'm doing wrong? Or how to achieve the desired result?

Here's the code below:

[AcceptVerbs(HttpVerbs.Post)]
    public ActionResult Login(User user)
    {
        var myErrors = new Dictionary<string, string>();
        try
            {


                if (ModelState.IsValid)
                {
                    if (userRepository.ValidUser(user))
                    {
                        RedirectToAction("Index", "Group");
                        //return Json("Valid");
                    }
                    else
                    {
                        return Json("Invalid");
                    }

                }
                else
                {
                    foreach (KeyValuePair<string, ModelState> keyValuePair in ViewData.ModelState)
                    {
                        if (keyValuePair.Value.Errors.Count > 0)
                        {
                            List<string> errors = new List<string>();

                            myErrors.Add(keyValuePair.Key, keyValuePair.Value.Errors[0].ErrorMessage);
                        }

                    }
                    return Json(myErrors);
                }
            }
            catch (Exception)
            {
                return Json("Invalid");
            }

        }

Edit: to clarify, I've already tried to return RedirectToAction("Index", "Group"); as suggested in the answers but it doesn't do anything. The breakpoint in the action I'm redirecting to doesn't get hit.

Answer 1

You need to change

RedirectToAction("Index", "Group"); 

to

return RedirectToAction("Index", "Group"); 

Answer 2

you shold return RedirectResult. Change this string

if (userRepository.ValidUser(user))
                    {
                        RedirectToAction("Index", "Group");
                        //return Json("Valid");
                    }

to

if (userRepository.ValidUser(user))
                    {
                        return RedirectToAction("Index", "Group");
                        //return Json("Valid");
                    }

and all will work fine.

Answer 3

Your missing a return statement:

return RedirectToAction("Index", "Group");

The Controller.RedirectToAction method returns a RedirectToRouteResult and Controller.Json method returns a JsonResult . Both extend ActionResult .

Answer 4

我认为你的重定向没有得到你想要的原因是它指向一个只接受获取的动作，你正在重定向一个帖子。