C# 排序下拉列表

我有下拉列表，需要排序。我试过了，但我对此表示怀疑

我的代码看起来像

    public ActionResult GetAgencyState(string statecode)
    {
        _logger.Info("GetAgencyState: " + statecode);
        AuthUserProfile profile = _sessionHelper.Get<AuthUserProfile>(SessionConstant.LightAUP);
        List<Light_AgenciesState> getAgenciesState = _mcpServiceHelper.GetAgenciesState(
            profile.au_key.ToString(), profile.officernode.ToString(), profile.role, statecode);
        Dictionary<string, string> agenciesState = new Dictionary<string, string>();
        agenciesState = getAgenciesState.ToDictionary(x => x.AgencyKey.ToString(), x => x.AgencyName);
        agenciesState = agenciesState.Count() == 0 ? null : agenciesState;
        agenciesState.OrderBy(agenciesState => agenciesState.Value);
        return Json(agenciesState, JsonRequestBehavior.AllowGet);
    }

调用此方法的我的JavaScript代码：

var GetAgencyStateUrl = "/Import/GetAgencyState";
 function OwnerStateFunction() {
var selectedVal = $("option:selected", $("#Ownerstate")).attr("Value");
if (selectedVal != "- select -" && selectedVal != "") {
    $.get(GetAgencyStateUrl, { 'statecode': selectedVal }, function (data) {
  $('#AgentPhone').val("");
        $.map(data, function (value, key) {
            var opt = "<option value=\"" + key + "\">" + value + "</option>";
            $("#OwnerAgency").append(opt);
        });
    }   

---

如何实现排序？

用此错误行替换您的错误行

 agenciesState.OrderBy(a => a.Value);

---

首先，不返回已排序的集合。您可以使用agenciesState.OrderByagenciesState=>agenciesState.Value；未将已排序集合分配给变量。这是必须的

var sorted = agenciesState.OrderBy(agenciesState => agenciesState.Value);
return Json(sorted, JsonRequestBehavior.AllowGet);

但是，代码还有其他问题，包括前一行

agenciesState = agenciesState.Count() == 0 ? null : agenciesState;

这意味着agenciesState可以为null，在这种情况下，下面的行将抛出异常

无论如何，你不应该还字典。控制器代码可以是

public ActionResult GetAgencyState(string statecode)
{
    ....
    List<Light_AgenciesState> getAgenciesState = _mcpServiceHelper.GetAgenciesState(....);
    var agenciesState = getAgenciesState.Select(a => new { Value = a.AgencyKey, Name = a.AgencyName });
}

然后在ajax函数中

var url = '@Url.Action("GetAgencyState", "Import")'; // dont hardcode!
var ownerAgency = $("#OwnerAgency"); // cache it

$("#Ownerstate").change(function() {
  var statecode = $(this).val();
  if (!statecode) {
    return;
  }
  $.get(url, { statecode: statecode }, function (data) {
    ownerAgency.empty(); // remove existing options
    $.each(data, function(index, item) {
      ownerAgency.append($('</option>').val(item.Value).text(item.Name));
    });
  });
});

---

并从html标记中删除onchange=ownerstate函数。

错误到底是什么？我猜您指的是agenciesState=agenciesState.OrderBy。。？但是如果这是为了填充下拉列表，为什么要返回字典？你是说值是选项显示文本，键是选项值吗？在前一行中，您可以潜在地将agenciesState设置为null-如何在null上调用OrderBy-它只会抛出一个异常。它不会在控制器代码中排序！并显示ajax调用您不应该返回字典-只需使用var agenciesState=getAgenciesState.Selecta=>new{value=a.AgencyKey，name=a.AgencyName}；返回JsonagenciesState。。。；在ajax调用中-$.eachdata，functionindex，item{$OwnerAgency.append$.valitem.Value.textitem.Name；向我展示您为DropDown编写的razor代码为什么要使用javascript？@Html.DropDownListddlName，new SelectListYourList，DataValue，DataKey；语法足以满足您的需求。

var url = '@Url.Action("GetAgencyState", "Import")'; // dont hardcode!
var ownerAgency = $("#OwnerAgency"); // cache it

$("#Ownerstate").change(function() {
  var statecode = $(this).val();
  if (!statecode) {
    return;
  }
  $.get(url, { statecode: statecode }, function (data) {
    ownerAgency.empty(); // remove existing options
    $.each(data, function(index, item) {
      ownerAgency.append($('</option>').val(item.Value).text(item.Name));
    });
  });
});