使用MVC如何綁定選定單選按鈕的列表？

Question

我有一些嵌套視圖模型用於顯示從數據庫驅動的調查問卷。顯示問題很簡單，但我不知道如何綁定到模型或解析提交時選擇的答案。

我的物體看起來像（僞）：

public class QuestionSheetViewModel(){ 
    public list<QuestionViewModel> Questions; 
    public string UserName; 
} 

public class QuestionViewModel(){ 
    public int QuestionId; 
    public string QuestionText; 
    public dictionary<int, string> answers; 
} 

在我看來，我遍歷問題，顯示每個問題的文本，然後渲染每一個答案，一個單選按鈕：

@Html.RadioButton(question.QuestionID, answer.Key()); 

通過使用question.questionId作爲單選按鈕名稱將它們分組在一起，從而將用戶限制爲每個問題一個答案。

當我提交時，模型的問題列表是空的。是否有可能自動綁定到我的視圖模型？如果不是，我需要做些什麼才能解析提交的表單以找到每個問題的選定答案？

謝謝

Answer 1

你能適應你的模型一點點的滿足您的要求：

public class QuestionSheetViewModel 
{ 
    public List<QuestionViewModel> Questions { get; set; } 
    public int QuestionId { get; set; } 
} 

public class QuestionViewModel 
{ 
    public string QuestionText { get; set; } 
    public int SelectedAnswerId { get; set; } 
    public List<AnswerViewModel> Answers { get; set; } 
} 

public class AnswerViewModel 
{ 
    public int AnswerId { get; set; } 
    public string Text { get; set; } 
} 

，然後有一個控制器：

public class HomeController : Controller 
{ 
    public ActionResult Index() 
    { 
     var model = new QuestionSheetViewModel 
     { 
      QuestionId = 1, 
      Questions = new[] 
      { 
       new QuestionViewModel 
       { 
        QuestionText = "question 1", 
        SelectedAnswerId = 2, 
        Answers = new[] 
        { 
         new AnswerViewModel { AnswerId = 1, Text = "answer 1" }, 
         new AnswerViewModel { AnswerId = 2, Text = "answer 2" }, 
        }.ToList() 
       }, 
       new QuestionViewModel 
       { 
        QuestionText = "question 2", 
        SelectedAnswerId = 3, 
        Answers = new[] 
        { 
         new AnswerViewModel { AnswerId = 3, Text = "answer 3" }, 
         new AnswerViewModel { AnswerId = 4, Text = "answer 4" }, 
        }.ToList() 
       }, 
      }.ToList() 
     }; 
     return View(model); 
    } 

    [HttpPost] 
    public ActionResult Index(QuestionSheetViewModel model) 
    { 
     // When the form is submitted the model will be properly bound 
     return View(model); 
    } 
} 

與相應的視圖（~/Views/Home/Index.cshtml） ：

@model QuestionSheetViewModel 

@using (Html.BeginForm()) 
{ 
    @Html.HiddenFor(x => x.QuestionId) 
    <ul> 
     @Html.EditorFor(x => x.Questions) 
    </ul> 
    <button type="submit">OK</button> 
} 

和它會自動按照慣例，每題（~/Views/Shared/EditorTemplates/QuestionViewModel.cshtml）呈現相應的編輯模板：

@model QuestionViewModel 

<li> 
    @Html.DisplayFor(x => x.QuestionText) 
    @Html.HiddenFor(x => x.QuestionText) 
    <ul> 
     @for (int i = 0; i < Model.Answers.Count; i++) 
     { 
      <li> 
       @Html.HiddenFor(x => x.Answers[i].AnswerId) 
       @Html.HiddenFor(x => x.Answers[i].Text) 
       @Html.RadioButtonFor(x => x.SelectedAnswerId, Model.Answers[i].AnswerId) 
       @Html.DisplayFor(x => x.Answers[i].Text) 
      </li> 
     } 
    </ul> 
</li>