How to pass List in Redirecttoaction

问题:

I want to pass more then one parameter from RedirectToAction method

how can I pass?

My One Action Method

 [HttpPost, ActionName("SelectQuestion")]
    public ActionResult SelectQuestion(string email,List<QuestionClass.Tabelfields> model)
    {

        List<QuestionClass.Tabelfields> fadd = new List<QuestionClass.Tabelfields>();
        for (int i = 0; i < model.Count; i++)
        {
            if (model[i].SelectedCheckbox == true)
            {
                List<QuestionClass.Tabelfields> f = new List<QuestionClass.Tabelfields>();
                fadd.Add(model[i]);
            }
        }

        return RedirectToAction("Question", new { email = email, model = fadd.ToList() });
    }

My another Action Method

    [HttpGet]
    public ActionResult Question(string email,List<QuestionClass.Tabelfields> model)
    {
    }

I am not getting values in model.

回答1:

You cannot pass a collection of complex objects in urls when redirecting.

One possibility would be to use TempData:

TempData["list"] = fadd.ToList();
return RedirectToAction("Question", new { email = email});

and then inside the Question action:

var model = TempData["list"] as List<QuestionClass.Tablefields>;

回答2:

This is probably not even active anymore, but I'll leave how I did it here to maybe help someone else.

I solved this using a simple Redirect instead of a RedirectToAction:

List<int> myList = myListofItems;
var list = HttpUtility.ParseQueryString("");
myList.ForEach(x => list.Add("parameterList", x.ToString()));
return Redirect("/MyPath?" + list);

Then, on your other method:

public ActionResult Action(List<int> parameterList){}

回答3:

RedirectToAction method Returns an HTTP 302 response to the browser, which causes the browser to make a GET request to the specified action.

You should either keep the data in a temporary storage like TempData / Session . TempData uses Session as the backing storage.

If you want to keep it real Stateless, you should pass an id in the query string and Fetch the List of items in your GET Action. Truly Stateless.

return RedirectToAction("Question", new { email = email,id=model.ID });

and in your GET method

public ActionResult Question(string email,int id)
{

   List<QuestionClass.Tabelfields> fadd=repositary.GetTabelFieldsFromID(id);
    //Do whatever with this
   return View();
}

Assuming repositary.GetTabelFieldsFromID returns a List of TabelFields from the Id

回答4:

The way that I solved this problem was to serialize the list to a JSON object using the JsonConvert method from the Newtonsoft.Json nuget package. Then the serialized list can be passed as a parameter and then deserialized again to re-create the original list.

So in your SelectQuestion method you would use this code:

return RedirectToAction("Question", 
    new { 
        email = email, 
        serializedModel = JsonConvert.SerializeObject(fadd.ToList()) 
    });

And in your Question method, you would use this code to deserialize the object.

[HttpGet]
public ActionResult Question(string email, string serializedModel)
{
    // Deserialize your model back to a list again here.
    List<QuestionClass.Tabelfields> model = JsonConvert.DeserializeObject<List<QuestionClass.Tabelfields>>(serializedModel);
}

Important, this adds the model as a query string parameter to your url, so only do this with really simple small objects, otherwise your url will be too long.