序列不包含 mvc 上的元素

本文关键字:元素 mvc 包含 | 更新日期: 2023-09-27 18:35:17

我不确定为什么我得到的序列不包含任何元素,我有点新 mvc

我的控制器

 [HttpPost]
            public ActionResult DeleteAnnounce(string announce)
            {
                using (var db = new HarmonyMainServerDbContext())
                {
                    ANNOUNCEMENT annoude = db.Announcer.First(c => c.AnnounceTitle == announce);
                    db.Announcer.Remove(annoude);
                    db.SaveChanges();
                }
                return RedirectToAction("ViewAnnounce");
            }

我的观点

<div id="clientDetailsContainer">
    @using (Html.BeginForm("Announcements", "Admin", FormMethod.Post, new { id = "Announcers" }))
    {
        @Html.AntiForgeryToken()
        @Html.ValidationSummary(true)
            <div class="module-controls" style="display:block;">
               <a href="/Admin/ViewAnnounce" class="k-button module-action"><img src="../Images/src/back.png"/><span>Back to List</span></a>
               <a class="k-button module-action" id="submitSave" title="haha"><img src="../Images/src/subgrid_save.png"/><span>Save</span></a>
               <a class="k-button module-action" id="submitDelete" ><img src="../Images/src/subgrid_save.png"/><span>Delete</span></a>
            </div>
        <h2>Announcement</h2>
        @Html.HiddenFor(model => model.AnnounceID)
        <div class="client-details" style="margin-left: 50px">


             <p>
                <label class="label-ant">Announcement Title</label>
                @Html.TextBoxFor(model => model.AnnounceTitle, new {@class="k-textbox", @style="width:250px" })
                @Html.ValidationMessageFor(model => model.AnnounceTitle)
            </p>
            <p>
                <label class="label-ant">Announcement Remarks</label>
                @Html.TextBoxFor(model => model.AnnounceRemarks, new {@class="k-textbox", @style="width:250px" })
                @Html.ValidationMessageFor(model => model.AnnounceRemarks)
            </p>
            <p>
                <label class="label-ant">Announce Link</label>
                @Html.TextBoxFor(model => model.AnnounceLink, new {@class="k-textbox", @style="width:250px" })
                @Html.ValidationMessageFor(model => model.AnnounceLink)
            </p>
        </div>
    }
   <script>
       $("#submitSave").click(function () {
           $("#Announcers").submit();
       });
       $("#submitDelete").click(function () {
           $("#Announcers").attr({
               "action" : "/Admin/DeleteAnnounce",
           });
       });
   </script>
</div>

序列不包含 mvc 上的元素

在集合中,您需要了解差异的方法很少

  1. 首先 - 意味着如果什么都没有返回,它将抛出异常,但它允许集合不止第一个
  2. 单个 - 表示只获得一个项目,因此如果集合匹配超过一个或没有你会得到例外,这是一种"约束"
  3. FirstOrDefault - 表示集合可以有多个项目匹配或没有匹配项
  4. 单个或默认 - 集合应只有一个或非项目匹配项目

这是因为您使用的是First()。如果没有具有匹配标题的播音员,这将引发异常。

请参阅 https://msdn.microsoft.com/library/bb291976%28v=vs.100%29.aspx