Model is getting null on post on Child Partial View MVC5 - asp.net-mvc-5

Question

I asked this question in a another thread but i never got the answer. Hope someone bright can help me with this.
Basically what i'm trying is to get TestModel back to ActionResult Questions(TestModel test, FormCollection formCollection). Whenever next button is pressed in _Question.cshtml partial View ActionResult Index(TestModel test) is bounded with empty model therefore i can't get anything from user to fill my testModel. Please Help
///////////////Models//////////////
[Serializable]
public class TestModel
{
private QuestionModel _currenQuestionModel;
public int TestID { get; set; }
public string TestName { get; set; }
public string Instructions { get; set; }
public double TestTime { get; set; }
public QuestionModel CurrenQuestionModel
{
get
{
if (_currenQuestionModel == null &&
Questions != null &&
Questions.Count > 0)
_currenQuestionModel = Questions.First();
return _currenQuestionModel;
}
set { _currenQuestionModel = value; }
}
public List<QuestionModel> Questions { get; set; }
}
public class QuestionModel
{
public int QuestionID { get; set; }
public string Question { get; set; }
public bool HasMultipleAnswers { get; set; }
public IList<PossibleAnswerModel> PossibleAnswers { get; set; }
}
public class PossibleAnswerModel
{
public bool IsSelected { get; set; }
public string DisplayText { get; set; }
}
}
////////////////// Controller /////////////////
public class TestController : Controller
{
public ActionResult Index(int id)
{
var model = _testColletion.FirstOrDefault(r => r.TestID == id);
return View(model);
}
[HttpPost]
public ActionResult Index(TestModel test)
{
//var model = (TestModel) Session["CurrentTest"];
return View(test);
}
[ChildActionOnly]
[HttpGet]
public ActionResult Questions(TestModel test)
{
var testModel = _testColletion.Single(r => r.TestID == test.TestID);
return PartialView("_Start", testModel);
}
[HttpPost]
public ActionResult Questions(TestModel test, FormCollection formCollection)
{
var q = formCollection.Count >2 ? formCollection.GetValues(1):null;
var testModel = _testColletion.FirstOrDefault(r => r.TestID == test.TestID);
//if (questionID == 0)
//{
// testModel.CurrenQuestionModel = testModel.Questions.First();
//}
if (!string.IsNullOrWhiteSpace(Request["next"]))
{
var nextQuestionIndex =
testModel.Questions.FindIndex(r => r.QuestionID == testModel.CurrenQuestionModel.QuestionID) + 1;
testModel.CurrenQuestionModel = testModel.Questions[nextQuestionIndex];
}
else if (!string.IsNullOrWhiteSpace(Request["prev"]))
{
var prevQuestionIndex =
testModel.Questions.FindIndex(r => r.QuestionID == testModel.CurrenQuestionModel.QuestionID) - 1;
testModel.CurrenQuestionModel = testModel.Questions[prevQuestionIndex];
}
return PartialView("_Question", testModel);
}
private static List<TestModel> _testColletion = new List<TestModel>()
{
new TestModel()
{
TestID = 1,
TestName = "ASP.NET",
Instructions = "Please choose from appropriate options",
TestTime = 2.40,
Questions = new List<QuestionModel>()
{
new QuestionModel(){QuestionID = 1, Question = "Question 1"}
}
},
new TestModel()
{
TestID = 2,
TestName = "ASP.NET MVC",
Instructions = "Please choose from appropriate options",
TestTime = 1.00,
Questions = new List<QuestionModel>()
{
new QuestionModel(){QuestionID = 1, HasMultipleAnswers=true, Question = "Question 1", PossibleAnswers = new List<PossibleAnswerModel>()
{
new PossibleAnswerModel(){DisplayText = "Possible Answer 1"},
new PossibleAnswerModel(){DisplayText = "Possible Answer 2"},
new PossibleAnswerModel(){DisplayText = "Possible Answer 3"},
new PossibleAnswerModel(){DisplayText = "Possible Answer 4"},
}},
new QuestionModel(){QuestionID = 2, HasMultipleAnswers=true, Question = "Question 2"},
new QuestionModel(){QuestionID = 3, HasMultipleAnswers=true, Question = "Question 3"},
new QuestionModel(){QuestionID = 4, HasMultipleAnswers=true, Question = "Question 4"},
new QuestionModel(){QuestionID = 5, HasMultipleAnswers=true, Question = "Question 5"},
}
},
new TestModel()
{
TestID = 3,
TestName = "ASP.NET Spring",
Instructions = "Please choose from appropriate options",
TestTime = 1.00,
Questions = new List<QuestionModel>()
{
new QuestionModel(){QuestionID = 1, Question = "Question 1"},
new QuestionModel(){QuestionID = 2, Question = "Question 2"},
new QuestionModel(){QuestionID = 3, Question = "Question 3"},
new QuestionModel(){QuestionID = 4, Question = "Question 4"},
}
},
new TestModel()
{
TestID = 4,
TestName = ".NET C#",
Instructions = "Please choose from appropriate options",
TestTime = 4.40,
Questions = new List<QuestionModel>()
{
new QuestionModel(){QuestionID = 1, Question = "Question 1"},
new QuestionModel(){QuestionID = 2, Question = "Question 2"}
}
}
};
}
/////////// Inside _Question.cshtml partial view///////////////
#model InterviewQ.MVC.Models.TestModel
#using (Html.BeginForm())
{
#Html.ValidationSummary(true)
#*#Html.HiddenFor(r => r.CurrentQuestionID)*#
<div>
<br />
<h4>Question #Model.CurrenQuestionModel.QuestionID</h4>
<hr />
<p>#Model.CurrenQuestionModel.Question</p>
</div>
<p>
#if (Model.CurrenQuestionModel.HasMultipleAnswers)
{
#Html.Partial("_MultipleAnswerQuestionView", Model.CurrenQuestionModel)
}
</p>
<p>
#if (Model.CurrenQuestionModel.QuestionID > 0 && Model.CurrenQuestionModel.QuestionID < Model.Questions.Count)
{
if (Model.CurrenQuestionModel.QuestionID > 1)
{
<input type="submit" class="btn btn-default" value="Previous" name="prev" />
}
<input type="submit" class="btn btn-default" value="Next" name="next" />
}
#if (Model.CurrenQuestionModel.QuestionID == Model.Questions.Count)
{
<input type="submit" class="btn btn-default" value="Finish" name="finish" />
}
</p>
}
//////////// Inside _MultipleAnswerQuestionView.cshtml partial view///////////////
#model InterviewQ.MVC.Models.TestModel
#if (!Model.CurrenQuestionModel.HasMultipleAnswers)
{
throw new InvalidOperationException("This answer optioin template doesn't support this type of questions");
}
#for (var i = 0; i < Model.CurrenQuestionModel.PossibleAnswers.Count; i++)
{
<div class="row">
<div class="col-lg-6">
<div class="input-group">
<span class="input-group-addon">
#Html.CheckBoxFor(r => r.CurrenQuestionModel.PossibleAnswers[i].IsSelected)
#*<input type="checkbox" value="#Model.CurrenQuestionModel.PossibleAnswers[i].IsSelected" name="#Model.CurrenQuestionModel.PossibleAnswers[i].IsSelected">*#
</span>
<p>
#Model.CurrenQuestionModel.PossibleAnswers[i].DisplayText
</p>
</div><!-- /input-group -->
</div><!-- /.col-lg-6 -->
</div><!-- /.row -->
}