ViewModel List对象在HTTPPost上返回Null

Question

我将表单发布回服务器，值始终为null。

型号：

public class RDetailsViewModel
{
    public RDetailsMaster RDetailsMaster { get; set; }
    public ETransaction ETransaction { get; set; }
}

public class RDetailsMaster
{
    [Required]
    public List<QE_DROPDOWN_MST> Master_EQ { get; set; }

    [Required]
    public List<QE_DROPDOWN_MST> Master_BASIS { get; set; }

    [Required]
    public List<QE_DROPDOWN_MST> Master_TE { get; set; }

    [Required]
    public List<QE_DROPDOWN_MST> Master_ALOP { get; set; }

    [Required]
    public List<QE_DROPDOWN_MST> Master_RISK { get; set; }

    [Required]
    public List<QE_DROPDOWN_MST> Master_EXCESS { get; set; }

    [Required]
    public List<QE_DROPDOWN_MST> Master_CType { get; set; }

}

控制器：

 [HttpPost]
    public ActionResult RDetails(RDetailsViewModel ObjR)        
    {
       return view();
    }

我的观点：

 @model QMS_ERater.ViewModels.RDetailsViewModel
 @{
    ViewBag.Title = "RDetails";
  }
<script src="~/Scripts/EAR/RDetails.js"></script>
@using (Html.BeginForm("RDetails", "RDetails", FormMethod.Post))
{   
<h2>RDetails</h2>
<div class="well well-sm">
    <div id="divDetail101" runat="server">
        <div class="row">
            <div class="col-sm-4">
                <span style="vertical-align: top; color: Red">*</span> EQ :
            </div>
            <div class="col-sm-3">
                @Html.DropDownListFor(m => m.ETransation.EQ, new SelectList(Model.RDetailsMaster.Master_EQ, "VALUE", "DESCRIPTION"), "--Select--", new { style = "width: 100%;" })
            </div>
            <div class="col-sm-2">
                <span style="vertical-align: top; color: Red">*</span> On First Loss Basis :
            </div>
            <div class="col-sm-3">
                @Html.DropDownListFor(m => m.ETransation.BASIS, new SelectList(Model.RDetailsMaster.Master_BASIS, "VALUE", "DESCRIPTION"), "--Select--", new { style = "width: 100%;" })
            </div>
            <div class="col-sm-4">
                <span style="vertical-align: top; color: Red">*</span> Terrorism :
            </div>

            <div class="col-sm-3">
                @Html.DropDownListFor(m => m.ETransation.IS_TE, new SelectList(Model.RDetailsMaster.Master_TE, "VALUE", "DESCRIPTION"), "--Select--", new { style = "width: 100%;" })
            </div>
            <div class="col-sm-2">
                <span style="vertical-align: top; color: Red">*</span> ALOP :
            </div>

            <div class="col-sm-3">
                @Html.DropDownListFor(m => m.ETransation.IS_ALOP, new SelectList(Model.RDetailsMaster.Master_ALOP, "VALUE", "DESCRIPTION"), "--Select--", new { style = "width: 100%;" })
            </div>

            <div class="col-sm-4">
                <span style="vertical-align: top; color: Red">*</span> Wet Risk :
            </div>

            <div class="col-sm-3">
                @Html.DropDownListFor(m => m.ETransation.IS_RISK, new SelectList(Model.RDetailsMaster.Master_RISK, "VALUE", "DESCRIPTION"), "--Select--", new { style = "width: 100%;" })
            </div>
        </div>
    </div>

    <input type="submit" value="Submit" />

</div>    

}

当我尝试使用call post方法 objR 时，仅为List对象返回NULL值。 任何帮助将不胜感激。 提前谢谢！