表單提交后保持模型

Question

我將以下模型用於測驗，我試圖提交表單並將現有模型傳遞回Action，因為它已在Index action中初始化。

public class QuizModel
{
    private List<string> _Responses;

    public List<string> Responses
    {
        get
        {
            if (_Responses == null)
            {
                _Responses = new List<string>() { "Response A", "Response B", "Response C", "Response D" };
            }
            return _Responses;
        }
    }

    public int? SelectedIndex { get; set; }

    public string Question { get; set; }
}

使用以下視圖：

<div class="title">Question</div>
<span id="question">@Model.Question</span>
@if (!Model.UserHasAnswered)
{
using (Html.BeginForm("Submit", "Quiz", FormMethod.Post))
{
    for (int i = 0; i < Model.Responses.Count; i++)
    {
        <div class="reponse">@Html.RadioButtonFor(m => m.SelectedIndex, i)@Model.Responses[i]</div>
    }
    <input type="submit" value="This is the value" />                              
}
}
else
{
    <div id="explanation">@Model.Explanation</div>
}

還有控制器

//
    // GET: /Quiz/

    public ActionResult Index()
    {
        QuizModel model = new QuizModel()
        {
            Question = "This is the question",
            Explanation = "This is the explanation",
            UserHasAnswered = false
        };

        return PartialView(model);
    }

    //
    // POST: /Quiz/Submit
    [HttpPost]
    public ActionResult Submit(QuizModel model)
    {
        if (ModelState.IsValid)
        {
            int? selected = model.SelectedIndex;

            model.UserHasAnswered = true;
        }

        return View("Index", model);
    }

當模型執行Submit操作時，它僅包含SelectedIndex，而不包含Question或解釋屬性。 如何告訴我的視圖將其收到的原始模型傳遞回Submit操作？

Answer 1

首次顯示索引時，將正確顯示您的問題和解釋。 然后，您提交表單，“問題和解釋”不會發送到“控制器操作”中。

這是因為您的FORM沒有包含問題和解釋的輸入字段。

將此添加到您的表單：

@Html.HiddenFor(x => x.Question)
@Html.HiddenFor(x => x.Explanation)

如果用戶可以對“說明”進行編輯，而不是為其添加“隱藏”，請執行以下操作：

@Html.TextAreaFor(x => x.Explanation)

切記：您需要發送給控制器的所有信息都必須位於FORM的INPUTS中。

這樣，您的視圖將變為：

<div class="title">Question</div>
<span id="question">@Model.Question</span>
@if (!Model.UserHasAnswered)
{
using (Html.BeginForm("Submit", "Quiz", FormMethod.Post))
{
    @Html.HiddenFor(x => x.Question)
    @Html.HiddenFor(x => x.Explanation)
    for (int i = 0; i < Model.Responses.Count; i++)
    {
        <div class="reponse">@Html.RadioButtonFor(m => m.SelectedIndex, i)@Model.Responses[i]</div>
    }
    <input type="submit" value="This is the value" />                              
}
}
else
{
    <div id="explanation">@Model.Explanation</div>
}

Answer 2

我相信您的index操作應類似於以下情況：

public ActionResult Index(QuizModel model)
{
    if(model == null) 
    {
        model = new QuizModel()
        {
            Question = "This is the question",
            Explanation = "This is the explanation",
            UserHasAnswered = false
        };
    }

    return PartialView(model);
}

希望這會有所幫助！