Posting Data to MVCC ViewModel

Question

This is an offshoot from a previous question I posted. Assuming I want to post a collection to a List Of that looks like this:

public class tbl_Log_ReviewOfSystems
    {
        public int? ID { get; set; }
        public int? ClientID { get; set; }
        public int? VisitID { get; set; }
        public int? MRNumber { get; set; }
        public int? QuestionID { get; set; }
        public int? CategoryCode { get; set; }
        public string? Category { get; set; }
        public string? EnglishDescription { get; set; }
        public string? QuestionResponse { get; set; }
        public DateTime? DateEntered { get; set; } = DateTime.Now;
}

But I want to post an additional input field that is a string called EnteredBy via an <input> field, I'm thinking I would create a ViewModel:

    public class ReviewOfSystemsVM
    {
        public string? EnteredBy { get; set; }
        public List<tbl_Log_ReviewOfSystems>? tbl_Log_ReviewOfSystems { get; set; }
    }

and then post to it, however, I am now unable to reference the List in the controller, receiving an object not set to reference error. The list works fine when using it by itself as the model. Any help would be appreciated.

Answer 1

Hi @Kmcnet, I change the code according to your previous question to fit your new requirement, Hoping it can give you some help.

Model

public class ReviewOfSystemsVM
    {
        public string? EnteredBy { get; set; }
        public List<tbl_Log_ReviewOfSystems>? tbl_Log_ReviewOfSystems { get; set; } = new List<tbl_Log_ReviewOfSystems>() { };
    }

Controller

public class SystemReviewController : Controller
    {
        public IActionResult Index()
        {
            ReviewOfSystemsVM reviewOfSystemsVM = new ReviewOfSystemsVM();
            reviewOfSystemsVM.tbl_Log_ReviewOfSystems = PopulateList();
            return View(reviewOfSystemsVM);
        }
        [HttpPost]
        public IActionResult InsertReviewOfSystems(ReviewOfSystemsVM model)
        {

            return Ok(model);
        }

        private List<tbl_Log_ReviewOfSystems> PopulateList()
        {
            return new List<tbl_Log_ReviewOfSystems>() {
                new tbl_Log_ReviewOfSystems()
                {
                    ClientID = 1,
                    VisitID= 9999999,
                    MRNumber= 5396,
                    QuestionID= 8112,
                    CategoryCode= 1,
                    Category= "General",
                    EnglishDescription= "BMI",
                    QuestionResponse= "None",
                    DateEntered= DateTime.Now,
                },
                new tbl_Log_ReviewOfSystems()
                {
                    ClientID = 1,
                    VisitID= 9999999,
                    MRNumber= 5396,
                    QuestionID= 2092,
                    CategoryCode= 1,
                    Category= "General",
                    EnglishDescription= "BODYACHES",
                    QuestionResponse= "None",
                    DateEntered= DateTime.Now,
                }
            };
        }
    }

View

@model ReviewOfSystemsVM

<h1>Index</h1>

<form method="post" action="/SystemReview/InsertReviewOfSystems">

    <div>
        @Html.LabelFor(Model=>Model.EnteredBy)
        @Html.TextBoxFor(Model=>Model.EnteredBy)
    </div>
    <table class="table">
        <thead>
            <tr>
                <th>
                    @Html.LabelFor(model => Model.tbl_Log_ReviewOfSystems[0].ClientID)
                </th>
                <th>
                    @Html.LabelFor(model => Model.tbl_Log_ReviewOfSystems[0].VisitID)
                </th>
                <th>
                    @Html.LabelFor(model => Model.tbl_Log_ReviewOfSystems[0].MRNumber)
                </th>
                <th>
                    @Html.LabelFor(model => Model.tbl_Log_ReviewOfSystems[0].QuestionID)
                </th>
                <th>
                    @Html.LabelFor(model => Model.tbl_Log_ReviewOfSystems[0].CategoryCode)
                </th>
                <th>
                    @Html.LabelFor(model => Model.tbl_Log_ReviewOfSystems[0].Category)
                </th>
                <th>
                    @Html.LabelFor(model => Model.tbl_Log_ReviewOfSystems[0].EnglishDescription)
                </th>
                <th>
                    @Html.LabelFor(model => Model.tbl_Log_ReviewOfSystems[0].QuestionResponse)
                </th>
                <th>
                    @Html.LabelFor(model => Model.tbl_Log_ReviewOfSystems[0].DateEntered)
                </th>
                <th></th>
            </tr>
        </thead>
        <tbody>
            @for (var i = 0; i < Model.tbl_Log_ReviewOfSystems.Count; i++)
            {
                <tr>
                    <td>
                        @Html.TextBoxFor(modelItem =>  Model.tbl_Log_ReviewOfSystems[i].ClientID)
                    </td>
                    <td>
                        @Html.TextBoxFor(modelItem =>  Model.tbl_Log_ReviewOfSystems[i].VisitID)
                    </td>
                    <td>
                        @Html.TextBoxFor(modelItem =>  Model.tbl_Log_ReviewOfSystems[i].MRNumber)
                    </td>
                    <td>
                        @Html.TextBoxFor(modelItem =>  Model.tbl_Log_ReviewOfSystems[i].QuestionID)
                    </td>
                    <td>
                        @Html.TextBoxFor(modelItem =>  Model.tbl_Log_ReviewOfSystems[i].CategoryCode)
                    </td>
                    <td>
                        @Html.TextBoxFor(modelItem =>  Model.tbl_Log_ReviewOfSystems[i].Category)
                    </td>
                    <td>
                        @Html.TextBoxFor(modelItem =>  Model.tbl_Log_ReviewOfSystems[i].EnglishDescription)
                    </td>
                    <td>
                        @Html.TextBoxFor(modelItem =>  Model.tbl_Log_ReviewOfSystems[i].QuestionResponse)
                    </td>
                    <td>
                        @Html.DisplayFor(modelItem =>  Model.tbl_Log_ReviewOfSystems[i].DateEntered)
                    </td>
                </tr>
            }
        </tbody>
    </table>
    <div>
        <input type="submit" value="submit" />
    </div>
</form>

---

If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Best regards,

Xinran Shen