Jquery 无法找到需要填充的DropDownList

我目前在一个页面上有两个下拉列表框。当用户进入页面并加载大约12个条目时，第一个条目是可见的。另一个dropdownlist使用样式隐藏，直到在第一个dropdownlist中进行选择。在做出选择后，第一个ddl上的change事件触发对我的控制器的ajax调用，以获取填充第二个ddl所需的数据。ajax调用正在获取正确的数据，因此在这里一切都很好

当我尝试填充第二个ddl时，问题就出现了。从Json返回时，jQuery无法找到我的第二个ddl。我得到的只是一个未定义的错误，它指向我试图对返回的数据进行数据绑定的时候

下面是代码

看法

我觉得这很简单，但我还没弄明白。我知道如果我实现一个不同的ddl，它就会工作。然而，我希望所有的东西都能流到一起，所以我使用这个ddl不是出于选择，而是为了整体的一致性

任何帮助都将不胜感激

最亲切的问候， 查德·约翰逊

var ddl = $("#SpecificationAttributeOptions").data("tDropDownList");

该行正在尝试获取附加到DropDownList的tDropDownList数据。它不会返回您的ddl，它可能返回未定义的，因为没有数据附加到您的ddl

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更多信息请参见此处：

因此我提出了自己的解决方案。我将次要ddl的HTML.DropDownList替换为一个普通的。这使我能够以不同的方式构建dropdownlist。以下是我所做的

看法

控制器

public ActionResult ProductBySpecificationAttribute()
    {
        if (!_permissionService.Authorize(StandardPermissionProvider.ManageReports))
            return AccessDeniedView();

        var model = new SpecificationAttributeReportListModel();
        var specificationAttributes = _specificationAttributeService.GetSpecificationAttributes();
        var specificationAttributesModel = PrepareSpecificationAttributeModel(specificationAttributes);
        model.SpecificationAttributes = specificationAttributesModel;

        //Return Model data
        return View(model);
    }

    public JsonResult GetSpecificationAttributeOptions(int specificationAttributeId)
    {
        var specificationAttributeOptions = _specificationAttributeService.GetSpecificationAttributeOptionsBySpecificationAttribute(specificationAttributeId);
        var specificationAttributeOptionsModel = PrepareSpecificationAttributeOptionsModel(specificationAttributeOptions);
        var returnData = new SelectList(specificationAttributeOptionsModel, "Id", "Name");
        return Json(returnData, JsonRequestBehavior.AllowGet);
    }

public ActionResult ProductBySpecificationAttribute()
    {
        if (!_permissionService.Authorize(StandardPermissionProvider.ManageReports))
            return AccessDeniedView();

        var model = new SpecificationAttributeReportListModel();
        var specificationAttributes = _specificationAttributeService.GetSpecificationAttributes();
        var specificationAttributesModel = PrepareSpecificationAttributeModel(specificationAttributes);
        model.SpecificationAttributes = specificationAttributesModel;

        //Return Model data
        return View(model);
    }

/// <summary>
    /// Used to load dropdownlist for SpecificationAttributeOptions
    /// </summary>
    /// <param name="specificationAttributeId">SpecificationAttribute Identifier</param>
    /// <returns>Json data to build dropdownlist</returns>
    public JsonResult GetSpecificationAttributeOptions(int specificationAttributeId)
    {
        //Get the SpecificationAttributeOptions for this SpecificationAttributeId
        var specificationAttributeOptions = _specificationAttributeService.GetSpecificationAttributeOptionsBySpecificationAttribute(specificationAttributeId);
        //Load data into SpecificationAttributeOptionModel
        var specificationAttributeOptionsModel = PrepareSpecificationAttributeOptionsModel(specificationAttributeOptions);
        //Pluck Id and Name from data
        var returnData = (from sao in specificationAttributeOptionsModel select new { id = sao.Id, name = sao.Name }).ToList();
        //Return specific data
        return Json(returnData, JsonRequestBehavior.AllowGet);
    }

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谢谢大家的回答和帮助。我很感激。希望这能帮助其他可能遇到同样问题的人。

当我把一个项目放进去时，这实际上没有任何帮助。我原以为是的，但那是我对它的不同实现。

<table width="100%">
    <tr>
        <td class="adminTitle">
            @Html.NopLabelFor(model => model.SpecificationAttribute):
        </td>
        <td class="adminData">
            @Html.DropDownListFor(model => model.SpecificationAttribute, new SelectList(Model.SpecificationAttributes, "Id", "Name"), "Select a Specification Attribute")
        </td>
    </tr>        
    <tr>
        <td class="adminTitle">
            <div class="SAOptions" style="display:none">
                @Html.NopLabelFor(model => model.SpecificationAttributeOption):
            </div>
        </td>
        <td class="adminData">
            <div class="SAOptions" style="display:none">
                <select id="SpecificationAttributeOptions"></select>
            </div>
        </td>
    </tr>
</table>
<script type="text/javascript">
//Change event for SpecificationAttribute
    $("#SpecificationAttribute").change(function () {
        var specificationAttributeId = $("#@Html.FieldIdFor(model => model.SpecificationAttribute)").val();
        //User selected one of the Specification Attributes
        if (specificationAttributeId != "") {
            //Show the Specification Attribute Options
            $(".SAOptions").show();

            //Load the now showing dropdownlist
            $.getJSON('@Url.Action("GetSpecificationAttributeOptions", "Reports")', { specificationAttributeId: specificationAttributeId }, function (data) {
                var ddl = $("#SpecificationAttributeOptions");
                if (data.length > 0) {
                    //Clear data from dropdownlist
                    ddl.html('');

                    //Bind dropdownlist
                    var elements = "";
                    $.each(data, function (id, option) {
                        elements += '<option value="' + option.id + '">' + option.name + '</option>'
                    });
                    ddl.append(elements);
                }
            });
        }
        //User selected "Select a Specification Option" for some reason, so hide everything
        else {
            $(".SAOptions").hide();
        }
    });
</script>

public ActionResult ProductBySpecificationAttribute()
    {
        if (!_permissionService.Authorize(StandardPermissionProvider.ManageReports))
            return AccessDeniedView();

        var model = new SpecificationAttributeReportListModel();
        var specificationAttributes = _specificationAttributeService.GetSpecificationAttributes();
        var specificationAttributesModel = PrepareSpecificationAttributeModel(specificationAttributes);
        model.SpecificationAttributes = specificationAttributesModel;

        //Return Model data
        return View(model);
    }

/// <summary>
    /// Used to load dropdownlist for SpecificationAttributeOptions
    /// </summary>
    /// <param name="specificationAttributeId">SpecificationAttribute Identifier</param>
    /// <returns>Json data to build dropdownlist</returns>
    public JsonResult GetSpecificationAttributeOptions(int specificationAttributeId)
    {
        //Get the SpecificationAttributeOptions for this SpecificationAttributeId
        var specificationAttributeOptions = _specificationAttributeService.GetSpecificationAttributeOptionsBySpecificationAttribute(specificationAttributeId);
        //Load data into SpecificationAttributeOptionModel
        var specificationAttributeOptionsModel = PrepareSpecificationAttributeOptionsModel(specificationAttributeOptions);
        //Pluck Id and Name from data
        var returnData = (from sao in specificationAttributeOptionsModel select new { id = sao.Id, name = sao.Name }).ToList();
        //Return specific data
        return Json(returnData, JsonRequestBehavior.AllowGet);
    }