How to pass List in Redirecttoaction

Question

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.

Answer 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>;

Answer 2

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.