Question

我在ma应用程序中有一个数据库驱动的下拉列表，通过它我从中选择一个值并显示与所选选项相关的数据。我这样做他页面重新加载并显示相关数据，但下拉列表的值更改为初始值，并且不保留选定的值。我在下面给了ma代码，请帮助我。

我的控制器操作：FilterCandidatesStatus（）是我进行下拉工作的地方，索引操作是针对页面数据有ropdown和te显示值显示的页面

[HttpGet]
    public ActionResult Index(int? page, int? filter)
    {
        ViewBag.statusName = db.CandidateStatuses.ToList();
        int pageSize = 12;
        int pageNumber = (page ?? 1);
        var candidates = new List<Candidate>();

        if (filter != null)
        {
            ViewBag.Filter = filter;
            candidates = db.Candidates.Where(m => m.CandidateStatusID == filter).OrderByDescending(m => m.CandidateID).ToList();
        }
        else
        {
            candidates = db.Candidates.OrderByDescending(m => m.CandidateID).ToList();
        }


        return View(candidates.ToPagedList(pageNumber, pageSize));
    }

    [HttpGet]
    public ActionResult FilterCandidateByStatus(int candidateStatusID)
    {

        return RedirectToAction("Index", new { filter = candidateStatusID });
    }

查看：

function fnFilterCandidtates()
 {
      window.location = "@Url.Action("FilterCandidateByStatus", "NewCandidate")?      candidateStatusID=" + $("#ddlStatus").val();
}
 <select class="h3c1" style=" height:31px; width:115px;" name="list" id="ddlStatus" onchange="fnFilterCandidtates(this)">
    <option value="" disabled selected>Select Status</option>
    @{
        foreach (var lstItem in (IEnumerable<Recruitment_System.Entities.CandidateStatus>)@ViewBag.statusName)
        {
            <option value="@lstItem.CandidateStatusID">@lstItem.StatusName</option>
        }
    }
</select>

我只给出了与我的下拉列表相关的代码。请帮助我。

Answer 1

您可以将它存储在TempData中，而不是存储在ViewBag中，如下所示：

TempData["Candidates"] = candidates;

并在View中读取之后这样做，所以它在TempData中重新输入，否则它会在第一次读取后从TempData中删除，在视图中这样做：

@{
IEnumerable<Recruitment_System.Entities.CandidateStatus> candidates = (IEnumerable<Recruitment_System.Entities.CandidateStatus>)TempData["Candidates"]

TempData.Keep("Candidates")

}

在你的行动中，你也必须坚持使用Keep in TempData

Answer 2

以防万一你有兴趣通过强类型视图

试试这个// 您可以在场景中使用的MY变通方法示例

public ActionResult Index()
        {
            LeadSortModel lsm = new LeadSortModel(); // model class 
            var SoucreList = //Pass you list to this 
            List<SelectListItem> lobj = new List<SelectListItem>();
            foreach (var item in SoucreList)
            {
                lobj.Add(new SelectListItem { Text = item.Lead_Source_Name , Value = item.Lead_Source_Name }); //here i taken text,value same becoz i want on select of text the thing what i selected should be saved not the id we usually :)
            }
            lsm.lead_sources = lobj; //leadsources will be present in Models like (public List<SelectedListItem> leadsources ;) . Here you are loading data to model and passing the entire model to make it strongly typed 

            return View(lsm); // return the model to view on initial load @HttpGET

        }

稍后发帖如果你想在HTTPPOST中加载DDL，只需用上面的foreach循环传递模型..

问候

Answer 3

我知道，您将选定的下拉值发送到FilterCandidateByStatus并从那里发送到Index。在那里，您将该值赋予ViewBag.Filter。因此，您可以在视图中使用该值：

@{
   int selectedValue = 0;
   if(ViewBag.Filter != null) { selectedValue = (int)ViewBag.Filter; }
}

function fnFilterCandidtates()
{
      window.location = "@Url.Action("FilterCandidateByStatus", "NewCandidate")?      candidateStatusID=" + $("#ddlStatus").val();
}
<select class="h3c1" style=" height:31px; width:115px;" name="list" id="ddlStatus" onchange="fnFilterCandidtates(this)">
<option value="" disabled selected>Select Status</option>
    @{
        foreach (var lstItem in (IEnumerable<Recruitment_System.Entities.CandidateStatus>)@ViewBag.statusName)
        {
            if(CandidateStatusID == selectedValue)
            {
               <option value="@lstItem.CandidateStatusID" selected>@lstItem.StatusName</option>
            }
            else
            {
               <option value="@lstItem.CandidateStatusID">@lstItem.StatusName</option>
            }
        }
    }
</select>

如何在MVC回发后的下拉列表中保留值

3 个答案: