将表单发布到控制器时，缺少ID

Question

I am developing a mvc website.I have a table called member .this table has a controller and the controller has an edit method as you can see :

 public ActionResult Edit()
        {
            int userId = _memberRepository.ReturnMemberIdByMobile(User.Identity.Name);
            ViewBag.Edit = _memberRepository.FindById(userId).First();
            return View();
        }
        [HttpPost]
        public ActionResult Edit(Member value)
        {
            try
            {
                if (_memberRepository.Edit(value))
                {

                    value.RegisteredDate = DateTime.Now;
                    _memberRepository.Save();
                    TempData["Success"] = "با موفقیت ویرایش شد ...";
                    string strLocation = HttpContext.Server.MapPath("~/Image/users");
                    if (value.ImgByte != null)
                    {
                        value.ImgByte.SaveAs(strLocation + @"\" + value.Id + ".jpg");
                    }
                }

            }
            catch (Exception)
            {
                TempData["Error"] = "ویرایش نشد، لطفاً مجدداً تلاش نمایید";


            }
            return RedirectToAction("Edit");

        }

The edit view is correctly work.the problem is when i post my view to edit controller .the id of member is changed to 0 it means it is missed.why ?and the value can't be edited.

  @using DCL
@{
    ViewBag.Title = "Edit";
    Layout = "~/Areas/user/Views/Shared/_shared.cshtml";
    Member membervalue = new Member();
    membervalue = ViewBag.Edit;

}

@using (@Html.BeginForm("Edit", "User", FormMethod.Post,
    new {id = "form", enctype = "multipart/form-data"}))
{
    if (TempData["Error"] != null)
    {
        <div class="pad margin no-print">
            <div class="callout callout-info" style="margin-bottom: 0 !important; background-color: #ea0000 !important; border-color: #d20000">
                @TempData["Error"]
            </div>
        </div>
    }
    if (TempData["Information"] != null)
    {
        <div class="pad margin no-print">
            <div class="callout callout-info" style="margin-bottom: 0 !important; background-color: orangered !important; border-color: red">
                @TempData["Information"]
            </div>
        </div>
    }
    if (TempData["Success"] != null)
    {
        <div class="pad margin no-print">
            <div class="callout callout-info" style="margin-bottom: 0 !important; background-color: #00A65A !important; border-color: #00925A">
                @TempData["Success"]
            </div>
        </div>
    }
    <div class="row">
        <!-- general form elements -->
        <div class="col-xs-12">
            <div class="box">
                <div class="box box-primary">
                    <div class="box-header with-border">
                        <h3 class="box-title">حساب کاربری</h3>
                    </div>
                    <!-- /.box-header -->
                    <!-- form start -->
                    <div class="box-body">
                        <div class="col-lg-7">
                            <div class="input-group">
                                <label for="Name">نام</label>
                                <input class="form-control" id="Name" name="Name" type="text" value="@membervalue.Name">
                            </div>
                            <div class="input-group">
                                <label for="family">نام خانوادگی</label>
                                <input class="form-control" id="family" name="family" type="text" value="@membervalue.Family">
                            </div>
                            <div class="input-group">
                                <label for="mobile">موبایل</label>
                                <input class="form-control" id="mobile" name="mobile" type="text" value="@membervalue.Mobile">
                            </div>
                            <div class="input-group">
                                <label for="password">رمز عبور</label>
                                <input class="form-control" id="password" name="password" type="password" value="@membervalue.Password">
                            </div>
                            <div class="input-group">
                                <label for="Email">ایمیل</label>
                                <input class="form-control" id="Email" name="Email" type="text" value="@membervalue.Email">
                            </div>
                            <div class="form-group">
                                <label for="ImgByte">عکس </label>
                                <input id="ImgByte" name="ImgByte" type="file">
                            </div>
                                     <input type="hidden"  id="Id" name="id" value="@membervalue.Id">

                        </div>
                    </div>
                    <!-- /.box-body -->
                </div>
            </div>
        </div>
        <!-- /.box -->

    </div>
        <div class="row" style="margin: 0; margin-bottom: 20px">
        <div class="box-footer" style="direction: ltr">
            <button type="submit" class="btn btn-info">ویرایش</button>
            <a class="btn btn-gray" href="@Url.Action("Index", "Home", null)">انصراف</a>
        </div>
    </div>
}

Answer 1

Instead of using the viewbag for your model you should pass in the model as a strongly typed object. You can do this with the following change in the Action. Then in your view define the model at the top and you can use it throughout the code. You will also need a @Html.HiddenFor tag for your id. Now it is no longer possible (without a compile time exception that is) to create a type-o. On your previous code maybe you cased Id incorrectly which would cause it not to be populated OR maybe the form field name was not cased correctly. This takes all those manual errors out of the equation.

    public ActionResult Edit()
    {
        int userId = _memberRepository.ReturnMemberIdByMobile(User.Identity.Name);
        var model = _memberRepository.FindById(userId).First();
        return View(model); // pass this in as the model, do not use viewbag
    }

View

@model = Member @* namespace qualified type *@

@*... editor code *@
@Html.HiddenFor(x => x.Id)
@Html.TextboxFor(x => x.Name) @* do this instead of manual input *@

Answer 2

I ran your code, and there is no mistake in it. Id is passed correctly to Edit (post) action. The only reason it can be empty in the code that you show is that FindById returned entity without Id property set.