asp.net-mvc – Asp.Net MVC：为什么我的视图将NULL模型传递给我

这是我的观点：

@model Non_P21_Quote_System_v1._0.Models.gl_code

@{
    ViewBag.Title = "Edit";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<h2>Edit</h2>

@if (TempData["Message"] != null)
{
    <div style="color:green">
        @TempData["Message"]
    </div><br />
}
@if (ViewBag.error != null)
{
    <div style="color:red">
        <h3>@ViewBag.error</h3>
    </div><br />
}

@using (Html.BeginForm())
{
    @Html.AntiForgeryToken()

    <div class="form-horizontal">
        <h4>gl_code</h4>
        <hr />
        @Html.ValidationSummary(true,"",new { @class = "text-danger" })
        @Html.HiddenFor(model => model.ID)

        <div class="form-group">
            @Html.LabelFor(model => model.GL_code,"GL Code",htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.GL_code,new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.GL_code,new { @class = "text-danger" })
            </div>
        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.GL_description,"Gl Description",htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.GL_description,new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.GL_description,new { @class = "text-danger" })
            </div>
        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.expense_type_ID,"Expense",htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.DropDownList("expense_type_ID",null,htmlAttributes: new { @class = "form-control" })
                @Html.ValidationMessageFor(model => model.expense_type_ID,new { @class = "text-danger" })
            </div>
        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.eag,"Employee Account Group",htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.DropDownList("eag",htmlAttributes: new { @class = "form-control" })
                @Html.ValidationMessageFor(model => model.eag,new { @class = "text-danger" })
            </div>
        </div>

        <div class="form-group">
            <div class="col-md-offset-2 col-md-10">
                <input type="submit" value="Save" class="btn btn-default" />
            </div>
        </div>
    </div>
}

<div>
    @Html.ActionLink("Back to List","gl_Index")
</div>

@section Scripts {
    @Scripts.Render("~/bundles/jqueryval")
}

这是我的控制器方法：

[HttpPost]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Edit([Bind(Include = "ID,GL_code,GL_description,expense_type_ID,eag")] gl_code gl_code)
{
    if (ModelState.IsValid)
    {           
        db.Entry(gl_code).State = EntityState.Modified;
        await db.SaveChangesAsync();
        return RedirectToAction("gl_Index");      
    }
    ViewBag.eag = new SelectList(db.employee_account_group,"ID","eag_name");
    ViewBag.expense_type_ID = new SelectList(db.expense_type,"type",gl_code.expense_type_ID);
    return View(gl_code);
}

当我调试它时,我看到传入的模型的值为NULL.我在控制器端看到这个在Edit方法的参数部分.