5

ポストバックすると、次のエラーが表示されます。

キー 'ClosingDateDay' を持つ ViewData アイテムのタイプは 'System.Int32' ですが、タイプは 'IEnumerable' である必要があります。何か案は？

これが私のコントローラーです：

CompetitionEditViewModel viewModel = new CompetitionEditViewModel
{
    ClosingDate = competition.CloseDate,
    Description = competition.Description,
    DescriptionHeading = competition.DescriptionHeading,
    ImageAssetId = competition.ImageAssetId,
    IsActive = competition.IsActive,
    MainHeading = competition.MainHeading,
    TermsAndConditions = competition.TermsAndConditions,
    UrlSlug = competition.UrlSlug
};

viewModel.ClosingDateMonthOptions = new List<SelectListItem>();
for (int i = 1; i <= 12; i++)
{
    string monthName = new DateTime(2000, i, 1).ToString("MMMM");
    ((List<SelectListItem>)viewModel.ClosingDateMonthOptions).Add(new SelectListItem { Text = monthName, Value = i.ToString() });
}

viewModel.ClosingDateDayOptions = new List<SelectListItem>();
for (int i = 1; i <= 31; i++)
{
    ((List<SelectListItem>)viewModel.ClosingDateDayOptions).Add(new SelectListItem { Text = i.ToString().PadLeft(2, '0'), Value = i.ToString() });
}

viewModel.ClosingDateYearOptions = new List<SelectListItem>();
for (int i = DateTime.Now.Year; i <= DateTime.Now.Year + 3; i++)
{
    ((List<SelectListItem>)viewModel.ClosingDateYearOptions).Add(new SelectListItem { Text = i.ToString(), Value = i.ToString() });
}

そして、私の見解は次のとおりです。

@Html.Uber().LabelFor(x => x.ClosingDateDay, new { @class = "access" })
@Html.DropDownListFor(x => x.ClosingDateDay, Model.ClosingDateDayOptions, Model.ClosingDateDay)

@Html.Uber().LabelFor(x => x.ClosingDateMonth, new { @class = "access" })
@Html.DropDownListFor(x => x.ClosingDateMonth, Model.ClosingDateMonthOptions, Model.ClosingDateMonth)

@Html.Uber().LabelFor(x => x.ClosingDateYear, new { @class = "access" })
@Html.DropDownListFor(x => x.ClosingDateYear, Model.ClosingDateYearOptions, Model.ClosingDateYear)
4

2 に答える 2

9

SelectListItem クラスを作成するときは、Selected最初に選択するアイテムのプロパティを true に設定します。

于 2012-06-21T19:43:42.270 に答える
1

私が自分のプロジェクトの1つで行ったことは、ある意味有用でしたが、
DropDownListFor受け入れる過負荷をさらに2つ開発することでしたselectedValue。 

namespace MyMvcApplication.Helpers
{
    public static class ExtensionMethods
    {
        public static MvcHtmlString DropDownListFor<TModel, TProperty>
                             (this HtmlHelper<TModel> helper,
                              Expression<Func<TModel, TProperty>> expression,
                              string selectedValue,
                              IEnumerable<SelectListItem> selectList,
                              string optionLabel,
                              object htmlAttributes)
        {
            if (string.IsNullOrEmpty(selectedValue))
                selectedValue = string.Empty;
            if (selectList != null)
            {
                foreach (SelectListItem sli in selectList)
                {
                    if (sli.Value.ToLower().Trim() == selectedValue.ToLower().Trim())
                    {
                        sli.Selected = true;
                        break;
                    }
                }
            }
            else 
            { 
                selectList = new List<SelectListItem>() 
                                  { new SelectListItem() 
                                          { Text = "", Value = "", Selected = true }
                                  };
            }
            return helper.DropDownListFor(expression, selectList, optionLabel, htmlAttributes);
        }


        public static MvcHtmlString DropDownListFor<TModel, TProperty>
                             (this HtmlHelper<TModel> helper,
                              Expression<Func<TModel, TProperty>> expression,
                              string selectedValue,
                              IEnumerable<SelectListItem> selectList,
                              string optionLabel,
                              IDictionary<string, object> htmlAttributes)
        {
            if (string.IsNullOrEmpty(selectedValue))
                selectedValue = string.Empty;
            if (selectList != null)
            {
                foreach (SelectListItem sli in selectList)
                {
                    if (sli.Value.ToLower().Trim() == selectedValue.ToLower().Trim())
                    {
                        sli.Selected = true;
                        break;
                    }
                }
            }
            else 
            { 
                selectList = new List<SelectListItem>() 
                                  { new SelectListItem() 
                                          { Text = "", Value = "", Selected = true } 
                                  };
            }
            return helper.DropDownListFor(expression, selectList, optionLabel, htmlAttributes);
        }

    }
}

したがって、ビューでは、次DropDownListForのように、 selectedValueとして文字列を渡すことができます。

@using MyMvcApplication.Helpers

@Html.DropDownListFor(model => model.MyData,
                               "Default Value for DropDownList", //Or Model.MySelectedValue
                               Model.MySelectList, null, mull)
于 2012-06-22T17:01:41.880 に答える