Question

我正在尝试使用下拉列表和一个用于输入文本的框来更新表，但是仍然在标题中出现错误。它直接从create cshtml中复制。

Index.cshtml：

 @model Announcements1.Models.Comment



<div id="CommentDiv"></div>
<div id="CommentCreateForm">

        @using (Ajax.BeginForm("AjaxCreate", "Comments",
                                new AjaxOptions
                                {
                                    InsertionMode = InsertionMode.Replace,
                                    HttpMethod = "POST",
                                    UpdateTargetId = "CommentDiv"
                                }))
        {

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

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


@section Scripts {
    <script src="~/Scripts/jquery.unobtrusive-ajax.min.js"></script>
    <script src="~/Custom_Scripts/BuildCommentTable.js"></script>
    @Scripts.Render("~/bundles/jqueryval")
  }

CommentController：

 public ActionResult BuildCommentTable()
        {
            var comments = db.Comments.Include(c => c.Announcement);
            return PartialView("_CommentTable", GetMyComments());
        }






[HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult AjaxCreate([Bind(Include = "CommentId,CommentContent,AnnouncementId")] Comment comment)
        {
            if (ModelState.IsValid)
            {
                db.Comments.Add(comment);
                db.SaveChanges();

            }

            ViewBag.AnnouncementId = new SelectList(db.Announcements, "AnnouncementId", "AnnouncementContent", comment.AnnouncementId);
            return PartialView("_CommentTable", db.Comments.Include(c => c.Announcement));
        }

和我的JS文件：

    $(document).ready(function () {
    $.ajax({
        url: '/Comments/BuildCommentTable',
        success: function (result) {
            $('#CommentDiv').html(result);
        }
    });

});

Answer 1

首先，您缺少在BuildCommentTable操作中填充Annoucements DropDownList数据的代码，在返回View之前添加它，就像在Post操作中一样。

其次，将ViewBag键命名为与Model属性相同，您的两个操作都应该具有ViewBag的范围：

ViewBag.AnnouncementOptions= new SelectList(db.Announcements, "AnnouncementId", "AnnouncementContent", comment.AnnouncementId);

所以你的行动就像：

public ActionResult BuildCommentTable()
{
     ViewBag.AnnouncementOptions= new SelectList(db.Announcements, "AnnouncementId", "AnnouncementContent");
     var comments = db.Comments.Include(c => c.Announcement);
     return PartialView("_CommentTable", GetMyComments());
}

同样改变后期操作方法ViewBag人口代码部分：

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult AjaxCreate([Bind(Include = "CommentId,CommentContent,AnnouncementId")] Comment comment)
{
    if (ModelState.IsValid)
    {
        db.Comments.Add(comment);
        db.SaveChanges();
    }

    ViewBag.AnnouncementOptions = new SelectList(db.Announcements, "AnnouncementId", "AnnouncementContent", comment.AnnouncementId);
    return PartialView("_CommentTable", db.Comments.Include(c => c.Announcement));
}

现在在您看来，您应该能够以这种方式使用强类型帮助方法DropDownListFor：

<div class="col-md-10">
  @Html.DropDownListFor(x=>x.AnnouncementId, ViewBag.AnnouncementOptions as SelectList, htmlAttributes: new { @class = "form-control" })
  @Html.ValidationMessageFor(model => model.AnnouncementId, "", new { @class = "text-danger" })
</div>

希望它对你有所帮助。

没有类型＆＃39; IEnumerable <selectlistitem>＆＃39;的ViewData项目。有关键的AnnouncementId

1 个答案: