Asp.net mvc 4 控制器未将Viewbag值返回到视图

我有一个名为CallAllocation的控制器和一个View CallAllocation。 首先，当页面加载时，仅会出现两个下拉列表，其中包含一个提交按钮。提交时，页面将根据两个下拉列表中的选择填充其余的详细信息。为了实现这一点，我编写了以下代码：

请关注ViewBag.IsValid条件

我的控制器就像

    [HttpGet]
    public ActionResult CallAllocation()
    {
        ViewBag.UserName = User.Identity.Name.ToString();
        try
        {
            var NatureList = (from a in dataContext.CallNatures
                              select a);

            Allocation Allocate = new Allocation();

            Allocate.CallNaturelist = NatureList.ToList();

            ViewData["SelectedTicket"] = 0;

            Allocate.CallTicketList = null;

            ViewBag.IsValid = "";

            return View(Allocate);
        }
        catch (Exception ex)
        {
            TempData["ErrMsg"] = ex.Message;
            return RedirectToAction("ShowError");
        }
    }

   @using (Html.BeginForm("CallAllocation", "Home", FormMethod.Post, new { id = "FrmCallAllocate"}))
                            {    
                                 @Html.AntiForgeryToken()
                                 @Html.ValidationSummary()
                                 @Html.Raw(ViewBag.ErrMsg)

                                <div class="row ">
                                    <div class="col-sm-12">
                                        @if (ViewBag.IsVaild == "True")
                                        {
                                            @Html.DropDownListFor(m => m.SelectedCallNature, new SelectList(Model.CallNaturelist, "CallNatureID", "Description"),
                                                            "Select Nature", new { style = "width:250px", @class = "dropdown1", @readonly = "readonly;" })   

                                            @Html.DropDownList("CallTicket", new SelectList(string.Empty, "CallTicketNumber", "CallTicketNumber"), "Select Call Ticket",
                                                        new { style = "width:250px", @class = "dropdown1" , @readonly = "readonly;" })   


                                                    <input type="submit" value="Get Ticket" style="background-color:#C5C5C5"/> 

                                        }
                                        else 
                                        {

                                         @Html.DropDownListFor(m => m.SelectedCallNature, new SelectList(Model.CallNaturelist, "CallNatureID", "Description"),
                                                            "Select Nature", new { style = "width:250px", @class = "dropdown1" })   

                                         @Html.DropDownList("CallTicket", new SelectList(string.Empty, "CallTicketNumber", "CallTicketNumber"), "Select Call Ticket",
                                                        new { style = "width:250px", @class = "dropdown1"})   


                                                    <input type="submit" value="Get Ticket" style="background-color:#C5C5C5"/> 
                                        }
                                    </div>
                                </div>

                            }

我的观点是

    [HttpGet]
    public ActionResult CallAllocation()
    {
        ViewBag.UserName = User.Identity.Name.ToString();
        try
        {
            var NatureList = (from a in dataContext.CallNatures
                              select a);

            Allocation Allocate = new Allocation();

            Allocate.CallNaturelist = NatureList.ToList();

            ViewData["SelectedTicket"] = 0;

            Allocate.CallTicketList = null;

            ViewBag.IsValid = "";

            return View(Allocate);
        }
        catch (Exception ex)
        {
            TempData["ErrMsg"] = ex.Message;
            return RedirectToAction("ShowError");
        }
    }

   @using (Html.BeginForm("CallAllocation", "Home", FormMethod.Post, new { id = "FrmCallAllocate"}))
                            {    
                                 @Html.AntiForgeryToken()
                                 @Html.ValidationSummary()
                                 @Html.Raw(ViewBag.ErrMsg)

                                <div class="row ">
                                    <div class="col-sm-12">
                                        @if (ViewBag.IsVaild == "True")
                                        {
                                            @Html.DropDownListFor(m => m.SelectedCallNature, new SelectList(Model.CallNaturelist, "CallNatureID", "Description"),
                                                            "Select Nature", new { style = "width:250px", @class = "dropdown1", @readonly = "readonly;" })   

                                            @Html.DropDownList("CallTicket", new SelectList(string.Empty, "CallTicketNumber", "CallTicketNumber"), "Select Call Ticket",
                                                        new { style = "width:250px", @class = "dropdown1" , @readonly = "readonly;" })   


                                                    <input type="submit" value="Get Ticket" style="background-color:#C5C5C5"/> 

                                        }
                                        else 
                                        {

                                         @Html.DropDownListFor(m => m.SelectedCallNature, new SelectList(Model.CallNaturelist, "CallNatureID", "Description"),
                                                            "Select Nature", new { style = "width:250px", @class = "dropdown1" })   

                                         @Html.DropDownList("CallTicket", new SelectList(string.Empty, "CallTicketNumber", "CallTicketNumber"), "Select Call Ticket",
                                                        new { style = "width:250px", @class = "dropdown1"})   


                                                    <input type="submit" value="Get Ticket" style="background-color:#C5C5C5"/> 
                                        }
                                    </div>
                                </div>

                            }

@使用（Html.BeginForm（“CallAllocation”，“Home”，FormMethod.Post，new{id=“frmcalallocate”}））
{    
@Html.AntiForgeryToken（）
@Html.ValidationSummary（）
@Html.Raw（ViewBag.ErrMsg）
@如果（ViewBag.IsVaild==“True”）
{
@Html.DropDownListFor（m=>m.SelectedCallNature，新建SelectList（Model.CallNaturelist，“CallNatureID”，“Description”），
“选择自然”，新建{style=“width:250px”、@class=“dropdown1”、@readonly=“readonly；”
@Html.DropDownList（“CallTicket”、新选择列表（string.Empty、“CallTicketNumber”、“CallTicketNumber”）、“Select Call Ticket”，
新的{style=“width:250px”、@class=“dropdown1”、@readonly=“readonly；”}）
}
其他的
{
@Html.DropDownListFor（m=>m.SelectedCallNature，新建SelectList（Model.CallNaturelist，“CallNatureID”，“Description”），
“选择自然”，新的{style=“width:250px”，@class=“dropdown1”}）
@Html.DropDownList（“CallTicket”、新选择列表（string.Empty、“CallTicketNumber”、“CallTicketNumber”）、“Select Call Ticket”，
新的{style=“width:250px”，@class=“dropdown1”}）
}
}

正如您所看到的，控制器发送ViewBag值“”，并且它应该进入视图的else条件。但它绕过了这两个条件。 请帮助我了解控制器无法将Viewbag值发送到视图的原因。我也做过类似的案例，但在其他情况下仍然有效。 我也尝试过清除缓存。

---

请注意，我的视图是强类型视图。

您的意思是它绕过了这两个条件？而

IsValid

（控制器）与

isavaild

（视图）不同，旁路意味着它没有进入else条件。你所说的IsValid（控制器）和IsAvaild（视图）是什么意思？仔细看看！（不同的拼写）是什么让您认为它没有进入

else

块代码是相同的（除了一个无意义且无效的

readonly

属性-没有只读

）那么为什么你甚至有一个

if/else

块呢？那是一个愚蠢的键入错误。