passing the dynamically generate input List form data from view to controller in asp.net

Question

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I have generated dynamic input fields grid and I want to bind to controller but I have tried many times but failed.When I submit the form then show null object on controller action.

Model class which is bound to the view; all properties name is accurately written in input fields names.

public class PvitalsDetails
{
    public Int64 PatientVitalId { get; set; }
    public Int64 PatientId { get; set; }
    public int VitalsInformationId { get; set; }
    public string Unit { get; set; }
    public string ImageUrl { get; set; }
    public string Readings { get; set; }
    public string Time { get; set; }
}

This is the view

@model List<PKLI.Model.Emr.PvitalsDetails>
<form role="form" action="@Url.Action("PatientVitals", "EMR")" method="post" id="FormVitals" onsubmit="return SubmitVitalFieldValues();">
     <div class="table-responsive">
        <table class="table table-striped">
            <thead>
                <tr>
                    <th>Vitals/Measurement</th>
                    <th>Values</th>
                    <th>Unit</th>
                    <th>Time Taken</th>
                </tr>
            </thead>
            <tbody>
               @foreach (PKLI.Model.Emr.PvitalsDetails item in ViewBag.Vitals)
               {
                <tr>
                    <td>
                        <input type="hidden"  name="VitalsInformationId" value="@item.VitalsInformationId" />
                        @item.Name
                    </td>
                    <td><input  placeholder="@item.Name" type="text" name="Readings"  class="form-control" /></td>
                    <td>
                        @item.Unit
                      <input type="hidden" name="Unit"   /> </td>
                    <td>
                        <input type="text" name="Time" 
                        class="form-control" 
                        placeholder="Enter Time" data-mask="99:99" />
                    </td>
                </tr>
             }
            </tbody>
        </table>
    </div>
    <input type="submit" class="btn btn-green"  value="submit"/>
<form>

Controller:

public ActionResult PatientVitals(List<PvitalsDetails> pvitalsDetails)
{
    var id = 0;
    var enterBy = SessionHelper.GetLoggedInUserId();
    var patientVitals = new PatientVitals();
    var patient = (Session["Patient"] as Patient) ?? new Patient();

    var response = new AjaxResponse
            {
                Code = 400,
                MessageClass = "warning",
                ResponseText = "Unable to process"
            };
    return response;
}