Question

I’m really new to programming and stuck on a problem.

I’m trying to edit and update multiple rows of a database in one view, using mvc and asp.net.
I think I’m somewhere along the right tracks but keep getting an error saying “not all code paths return a value”.
My Conroller looks like this:

 [HttpGet]
    public ViewResult AnotherListEdit()
    {
        var chosenClass = from c in db.ClassInstanceDetails.Include("ClassInstance").Include("Student")
                          where c.ClassInstance.ID == 1
                          select c;

        return View(chosenClass.ToList());
    }


    [HttpPost]
    public ActionResult AnotherListEdit(IList<ClassInstanceDetail> list)
    {
        if (ModelState.IsValid)
        {
            foreach (ClassInstanceDetail editedClassInstanceDetail in list)
            {
                var tempBook = (from classInstDet in db.ClassInstanceDetails
                                where (teacher.ClassInstanceID == editedClassInstanceDetail.ClassInstanceID)
                                && (classInstDet.StudentID == editedClassInstanceDetail.StudentID)
                                select teacher).First();

                db.ApplyCurrentValues(tempBook.EntityKey.EntitySetName, editedClassInstanceDetail);
            }
            db.SaveChanges();
            return View(db.Teachers.ToList());
        }


    }

My View looks like this:

    @model IList<FYPSchoolApp.DAL.ClassInstanceDetail>

@{
    ViewBag.Title = "AnotherListEdit";
}

@using (Html.BeginForm())
{
    <table>
        <tr>
            <th>
                Name
            </th>
             <th>
                Second Name
            </th>
            <th>
                attendance
            </th>
            <th>
                Comment
            </th>

        </tr>

        @for (var i = 0; i < Model.Count(); i++) {
            <tr>
                <td>
                    @Html.DisplayFor(m => Model[i].StudentID)
                </td>
                <td>

                    @Html.DisplayFor(m => Model[i].Attendance)
                    @Html.EditorFor(m => Model[i].Attendance)
                </td>
                <td>

                    @Html.DisplayFor(m => Model[i].CommentNote)
                    @Html.EditorFor(m => Model[i].CommentNote)
                </td>
            </tr>
            }

     </table>
     <input type="submit" value="save" />
}

The “not all code paths return a value error” is being highlighted with AnotherListEdit function, the second one thats after HttpPost. If I run the project without that whole function, the display works, and the correct information is passed to the display.

Any help would be very much appreciated!!

Answer 1

What should happen in the AnotherListEdit method if the modelstate is invalid? That is what is missing … The action does not return a “ActionResult” if the modelstate is invalid

[HttpPost]
    public ActionResult AnotherListEdit(IList<ClassInstanceDetail> list)
    {
        if (ModelState.IsValid)
        {
            foreach (ClassInstanceDetail editedClassInstanceDetail in list)
            {
                var tempBook = (from teacher in db.ClassInstanceDetails
                                where (teacher.ClassInstanceID == editedClassInstanceDetail.ClassInstanceID)
                                && (teacher.StudentID == editedClassInstanceDetail.StudentID)
                                select teacher).First();

                db.ApplyCurrentValues(tempBook.EntityKey.EntitySetName, editedClassInstanceDetail);
            }
            db.SaveChanges();
            return View(db.Teachers.ToList());
        }
       //HERE!!What view should return? any error messages?
        return View("View with no valid modelstate?");

        //Maybe?
        //return RedirectToAction("AnotherListEdit");

    }