Question

我想在MVC 5中有下拉列表，我想知道用户选择了哪个项目。我正在搜索并找到以下解决方案，但在Http.DropDownList中的View代码错误

new{id ="dropdownlist1"}

我的代码是：

在我的控制器中我有：

public ViewResult ExistHW()
    {
        #region
        List<SelectListItem> HWType = new List<SelectListItem>();

        HWType.Add(new SelectListItem { Text = "Monitor ", Value = "Monitor" });

        HWType.Add(new SelectListItem { Text = "Case", Value = "Case" });

     .....

        #endregion
        ViewBag.HWType = HWType;


        return View(); }

我是我的观点：

  @Html.DropDownList("HWType", "-- select ---",new{ id = "dropdownlist1"} )

            $('#dropdownlist1').change(function () {
            jQuery.getJSON('@Url.Action("SelectType")', { id: $(this).attr('value') }, function(data) { });

那在我的控制者中：

public ActionResult SelectType(String value)
    {
        switch (value)
        {case "Monitor":
                break;
        case "Case":
                break;

      ....
        }
       return View();
    }

Answer 1

在致电getJSON时，您将id参数传递给SelectType。但是，根据操作方法的签名，参数应命名为value

将getJSON来电更改为：

jQuery.getJSON('@Url.Action("SelectType")', 
               { value: $(this).attr('value') }, 
               function(data) { });

Answer 2

如果您想根据DropDownList中的选定项目更改部分页面，可以使用以下示例并根据您的情况进行更新：

<script type="text/javascript">
    $(document).ready(function () {
        submitform = function (flag) {
            var ProductCatID = $("#ProductCategoryId").val();
            var param = { ProdCatID: ProductCatID, Flag: flag };
            var ul = '@Url.Action("GetProdPropertyValues", "ManageProducts")';
            $.ajax({
                url: ul + "?ProdCatID=" + ProductCatID + "&&Flag=" + flag,
                type: 'GET',
                async: true,
                success: function (result) {
                    if (result != "") {
                        $("#partialView").empty();
                        $("#partialView").html(result);
                    }
                },
                error: function (xhr, status, error) {
                    alert("R:" + xhr.responseText + " S:" + status + " E:" + error);
                }
            });
        }
    });
</script>

@using (Html.BeginForm())
{
    @Html.ValidationSummary(true)

    <fieldset>
        <legend>Product</legend>
        <div class="editor-label">
            @Html.LabelFor(model => model.ProductCategoryId)
        </div>
        <div class="editor-field">
            @Html.DropDownListFor(model => model.ProductCategoryId, (SelectList)ViewBag.ProductCategoriesSelectList, "Select", new { onchange = "submitform('dropdown')" })

            @Html.ValidationMessageFor(model => model.ProductCategoryId)
        </div>
        <div class="editor-label">
            @Html.LabelFor(model => model.SpecialName)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.SpecialName)
            @Html.ValidationMessageFor(model => model.SpecialName)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.InitialPrice)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.InitialPrice)
            @Html.ValidationMessageFor(model => model.InitialPrice)
        </div>


        <div id="partialView">
        </div>

        <p>
            <input type="submit" value="Create" />
        </p>
    </fieldset>
}

部分视图控制器：

public ActionResult GetProdPropertyValues(string ProdCatID, string flag)
        {
            if (flag == "dropdown" && !String.IsNullOrEmpty(ProdCatID))
            {
                ProductCategory category = db.ProductCategories.Find(Byte.Parse(ProdCatID));
                if (category != null && category.ProductProperties != null)
                {
                   return PartialView("ProdPropValues", category.ProductProperties);
                }

            }
            return PartialView("ProdPropValues", null);
        }

如何知道MVC中哪个选定项目DropDownlist

2 个答案: