MVC 5 ActionResult参数始终为空

Question

我是MVC的新手，我的英语很差。现在，我在ActionResult参数中始终将参数设置为null。

这是控制者

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit([Bind(Include = "TimeCodeId, Code, Title, Description, IsValid, DateCreated")] TimeCodeInfo infoTimeCode, string submitButton)
{
        bool result;

        switch (submitButton)
        {
            case "Update":
            case "Enregistrer":
                infoTimeCode.LastDateModified = DateTime.Now;
                result = _mTimeCode.Update(infoTimeCode);
                return RedirectToAction("List");

            case "Cancel":
            case "Annuler":
                return RedirectToAction("List");
                //break;
        }

        return View(infoTimeCode);
}

这是cshtml

@using (Html.BeginForm("Edit", "TimeCode", FormMethod.Post))
{

    @Html.AntiForgeryToken()
    @Html.ValidationSummary(true)
    @Html.HiddenFor(Model => Model.TimeCodeId)

    <table class="w3-table w3-card">
        <tr>
            <td>Code:</td>
            <td>
                @Html.EditorFor(model => model.Code)
                @Html.ValidationMessageFor(model => model.Code)
            </td>
        </tr>
        <tr>
            <td>Titre:</td>
            <td>
                @Html.EditorFor(model => model.Title)
                @Html.ValidationMessageFor(model => model.Title)
            </td>
        </tr>
        <tr>
            <td>Description:</td>
            <td>
                @Html.EditorFor(model => model.Description)
                @Html.ValidationMessageFor(model => model.Description)
            </td>
        </tr>
        <tr>
            <td>Est valide ?</td>
            <td>

                @Html.EditorFor(model => model.IsValid)
                @Html.ValidationMessageFor(model => model.IsValid)
                <label class="switch" onsubmit="@Model.IsValid = getCheckBoxValue('switchCheckBox')">
                    <input id="switchCheckBox" type="checkbox" name="IsValid">
                    <span class="slider round"></span>
                </label>
            </td>
        </tr>
        <tr>
            <td>Date de création:</td>
            <td>@Model.DateCreated</td>
        </tr>
        <tr>
            <td>Dernière modification:</td>
            <td>@Model.LastDateModified</td>
        </tr>
    </table>

    <br />
    <a href="/TimeCode/List" class="w3-round-medium w3-button w3-blue"><i class="fa fa-caret-left"></i>  Retour à la liste</a>

    <div class="float-right">
        <button type="submit" value="enregistrer"> enregistrer </button>
        @*<a type="submit" href="~/Views/TimeCode/List.cshtml" class="w3-right w3-round-medium button buttonBlue">Enregistrer</a>*@
        <a href="/TimeCode/List" class="w3-right w3-round-medium button buttonBlue">Annuler</a>
    </div>
}

调试时，参数submitButton始终为null。有人看到问题出在哪里吗？我需要添加更多详细信息吗？

谢谢！