MVC post form return null

Question

I'm trying to make a dynamic form for tests. My problem is when i submit that from, in post method in controller List gq is null, but im expecting to be filled with data that was filled in form. I can guess that it have to do something with @Html.EditorForModel() and data binding, but i dont fully understand how it works. Any idea? Thank you

Model:

public class GeneratedQuestions
{
    public int GeneratedQuestionsId { get; set; }

    public string QuestionText { get; set; }
    public List<StudentAnswer> QuestionAnswers { get; set; }

    public int StudentTestsId { get; set; } 
    public virtual StudentTest StudentTests { get; set; }
}

View:

@model IEnumerable<Project.Models.GeneratedQuestions>

@{
    ViewBag.Title = "StartTest";
}

@using (Html.BeginForm())
{
   @Html.EditorForModel()

    foreach (var question in Model)
    {
        <br />
        <h1>@question.QuestionText</h1>

        foreach (var answer in question.QuestionAnswers)
        {
            @Html.CheckBoxFor(x => answer.WasChecked)
            @Html.DisplayFor(x => answer.AnswerText)
            @Html.HiddenFor(x => answer.GeneratedQuestionsId)
            <br />
        }
    }
    <input type="submit" value="Submit" />
}

Controller:

public ActionResult StartTest(int id)
{
    List<GeneratedQuestions> generatedQuestions = db.StudentTests.Find(id).GeneratedQuetions.ToList();
    return View(generatedQuestions);
}


[HttpPost]
public ActionResult StartTest(List<GeneratedQuestions> gq)
{
    //stuff
    return RedirectToAction("Index");
}

You need to use `for` instead of `foreach`. [Here](http://stackoverflow.com/questions/17037858/how-to-pass-ienumerable-list-to-controller-in-mvc-including-checkbox-state) is just one in many other similar questions regarding enumerable models and forms. — Andrei V, Jun 19 '15 at 12:24

score 0 · Accepted Answer · edited May 23 '17 at 12:14

0

As seen on here:

ASP.NET MVC 4 - for loop posts model collection properties but foreach does not

MVC helpers hate foreach loops. Go for a for loop and everything should work fine.

Write both loop and inspect them using web developer tools to see the difference in the 'id' and 'name' attribute.

edited May 23 '17 at 12:14

Community

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answered Jun 19 '15 at 12:33

Quovadisqc

81
7

MVC post form return null

1 Answers1