MVC 中下拉列表的动态填充

Question

好的，我有一个名为 QuestionnaireTable 的问题表。 该表具有以下属性：

QuestionnaireID    QuestionID    ChoiceType  ListOfAnswers QuestionLabel
---------------    ----------    ----------  ------------- -------------
AAA1               Quest1        enum        ListA         Pick a shape
AAA1               Quest2        string                    What is your name
AAA1               Quest3        enum        ListB         Pick a colour
AAA2               Quest1        enum        ListA         Pick a shape
AAA2               Quest4        number                    What is your age

我有第二个表，名为 QuestionMultiSelectTable 该表具有以下属性：

ListOfAnswersID Options
----------      ----------
ListA           Square
ListA           Triangle
ListA           Circle
ListA           Rectangle
ListB           Blue
ListB           Red

所以我将 QuestionnaireTable 读入 Viewbag（进入 ViewBag.QuestionsList），并可以遍历每个项目以获取正确的问卷（以问卷“AAA1”为例）。 但是，如果选择类型是“枚举”，那么我需要使用 QuestionMultiSelectTable 表中具有相同 ListOfAnswersID 的不同列表填充下拉列表

@foreach (var QuestionItem in ViewBag.QuestionsList)
{
    if (QuestionItem.OptionsType == "enum")
    {
        <div class="form-group">
            <div class="control-label col-md-3">
                @QuestionItem.QuestionLabel:
            <div>
            <div class="col-md-9">
                @Html.DropDownList((string)QuestionItem.QuestionID, Enumerable.Empty<SelectListItem>(),
                         "Select answer",
                         new { @class = "form-control" })
            </div>
        </div>
        }
        else
        {
            <div class="form-group">
                <div class="control-label col-md-3">
                    @QuestionItem.QuestionLabel:
                </div>
                <div class="col-md-9">
                    @Html.TextBox((string)QuestionItem.QuestionLabel, "0", new { @class = "form-control" })
                </div>
            </div>
        }
    }

现在我很想知道如何使用 QuestionMultiSelectTable 表中的正确答案列表填充此下拉列表。 问卷、问题和可能的答案列表会不断更改、添加和删除。

那么对于在 MVC 中无需为页面创建复杂主类的最佳方法有什么建议吗？ （请注意，这只是页面中发生的事情的一小部分，因此除非没有其他方法，否则不想四处创建自定义类）

理想情况下，我希望在每个下拉列表已经/正在构建时可以调用一个操作，使用“ListOfAnswersID”，然后填充它。 但我很难在任何地方找到示例。

Answer 1

https://dotnetfiddle.net/Kpin7x

创建表格 - 我添加了一个 id

CREATE TABLE [AHCCCS\KXBlau].[QuestionMultiSelect](
    [Id] [int] IDENTITY(1,1) NOT NULL,
    [ListOfAnswersID] [char](5) NOT NULL,
    [Options] [varchar](20) NULL,
 CONSTRAINT [PK_QuestionMultiSelect] PRIMARY KEY CLUSTERED 
(
    [Id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

CREATE TABLE [AHCCCS\KXBlau].[Questionnaire](
    [Id] [int] IDENTITY(1,1) NOT NULL,
    [QuestionnaireID] [char](4) NULL,
    [QuestionID] [char](6) NULL,
    [ChoiceType] [varchar](6) NULL,
    [ListOfAnswers] [char](5) NULL,
    [QuestionLabel] [varchar](20) NULL,
 CONSTRAINT [PK_Questionnaire] PRIMARY KEY CLUSTERED 
(
    [Id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

去

控制器/视图模型

public class BigMBViewModel
{
    public IList<SelectListItem> QuestionMultiSelectList { get; set; }
}

public class HomeController : Controller
{
    [HttpPost]
    public ActionResult Tut141(FormCollection formCollection)
    {
        ArrayList results = new ArrayList();
        for (int i = 0; i < formCollection.Count; i++)
        {
            if (formCollection[i].Contains("List"))
            {
                results.Add(formCollection[i]);
            }
        }

        return View();
    }

    public ActionResult Tut141()
    {
        //I am using entity framework.  You can use plain ADO
        //read the the QuestionnaireTable into the Viewbag (into ViewBag.QuestionsList
        using (SMARTEntities2 entity = new SMARTEntities2())
        {
            ViewBag.QuestionsList = entity.Questionnaires.ToList();
        }

        BigMBViewModel bmbViewModel = new BigMBViewModel { QuestionMultiSelectList = new List<SelectListItem>() };

        using (SMARTEntities2 entity = new SMARTEntities2())
        {
            entity.QuestionMultiSelects.ToList().ForEach(r => bmbViewModel.QuestionMultiSelectList.Add(
                new SelectListItem { Text = r.Options, Value = r.ListOfAnswersID + "-" + r.Id.ToString() }));            }

        return View(bmbViewModel);
    }

查看

@model Testy20161006.Controllers.BigMBViewModel
@{
    Layout = null;
}
<!DOCTYPE html>
<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Tut141</title>
</head>
<body>
    @using (Html.BeginForm())
    {
        int index = 0;
        foreach (var QuestionItem in ViewBag.QuestionsList)
        {
            //fixed the next line
            //if (QuestionItem.OptionsType == "enum")
            if (QuestionItem.ChoiceType == "enum")
            {
                ++index;
                <div class="form-group">
                    <div class="control-label col-md-3">
                        @QuestionItem.QuestionLabel:
                        @*fixed the next end div to be an end div instead of a begin div*@
                    </div>
                    <div class="col-md-9">
@{
                        var listOfAnswers = QuestionItem.ListOfAnswers;
                        var q = Model.QuestionMultiSelectList.ToList().Where(r => r.Value.Contains(listOfAnswers));
                        var theList = new
                        SelectList(Model.QuestionMultiSelectList, "Value", "Text");
                        }
                        @Html.DropDownList("theList" + index, q,
                            new { @id = "getThisValue", @class = "form-control" })

                    </div>
                </div>
            }
            else
            {
                <div class="form-group">
                    <div class="control-label col-md-3">
                        @QuestionItem.QuestionLabel:
                    </div>
                    <div class="col-md-9">
                        @Html.TextBox((string)QuestionItem.QuestionLabel, "0", new { @class = "form-control" })
                    </div>
                </div>
            }
        }
        <input type="submit" value="submit" />
    }
</body>
</html>