小编典典

ASP.NET MVC 5组单选按钮

c#

我正在开始我的第一个ASP.NET MVC项目,所以我有一个简单的问题。我有以下代码:

foreach(var question in Model.GeneralQuestions)
{
    <div class = "well">
        <h3>
            <strong>@question.QuestionString</strong>
        </h3>
        @foreach (var answer in question.PossibleAnswers)
        {
            @Html.RadioButtonFor(model => question.QuestionString, answer.Answer)
            @Html.Label(answer.Answer)
            <br />
        }
    </div>
}

Model.GeneralQuestions中的所有问题都是唯一的,因此单选按钮应按名称属性分为几组(对于每个问题,一组单选按钮)。但是此代码仅产生一组,因此当我回答第二个问题时,第一个被取消选择。我需要更改什么?

编辑
我的模型看起来像:

public class StudentViewModel
{
    public Student Student { get; set; }
    public List<Question> GeneralQuestions { get; set; }
    public List<SubjectQuestions> SubjectQuestions { get; set; }
}
public class Student
{
    public int StudentID { get; set; }
    public string Index { get; set; }
    public string Name { get; set; }
    public string Surname { get; set; }

    public virtual ICollection<Subject> Subjects { get; set; }
}
public class Question
{
    public int QuestionID { get; set; }
    public string QuestionString { get; set; }
    public bool IsAssociatedWithSubject { get; set; }

    public virtual ICollection<PossibleAnswer> PossibleAnswers { get; set; }
    public virtual ICollection<Results> Results { get; set; }
}
public class SubjectQuestions
{
    public Subject Subject { get; set; }
    public List<Question> Questions { get; set; }
}
public class Results
{
    public int ResultsID { get; set; }
    public int QuestionID { get; set; }
    public int? SubjectID { get; set; }
    public int PossibleAnswerID { get; set; }

    public virtual Question Question { get; set; }
    public virtual PossibleAnswer PossibleAnswer { get; set; }
    public virtual Subject Subject { get; set; }
}

在一个StudentViewModel实例中,我保存了一个学生和他应该回答的所有问题(包括与他正在研究的学科有关的一般问题),并将其传递给视图。我认为所有问题都以单一形式提出,它们都是无线电的类型。因此,有人可以帮助我将单选按钮分组并正确发回此表单吗?


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2020-05-19

共1个答案

小编典典

您的代码存在许多问题,包括生成重复id的(无效的html),生成重复的name属性(这就是为什么您仅创建一组的原因,但更重要的是,这将阻止您在回发时绑定到模型),那么您实际上并没有绑定到有效的属性。

您将需要创建视图模型来表示要显示和编辑的视图,并在for循环中(或使用EditorTemplate)生成单选按钮,以便使用索引器正确命名它们。

查看模型

public class QuestionVM
{
  public int ID { get; set; } // for binding
  public string Text { get; set; }
  [Required]
  public int? SelectedAnswer { get; set; } // for binding
  public IEnumerable<AnswerVM> PossibleAnswers { get; set; }
}

public class SubjectVM
{
  public int? ID { get; set; }
  [DisplayFormat(NullDisplayText = "General")]
  public string Name { get; set; }
  public List<QuestionVM> Questions { get; set; }
}

public class AnswerVM
{
  public int ID { get; set; }
  public string Text { get; set; }
}

public class StudentVM
{
  public int ID { get; set; }
  public string Name { get; set; }
  // plus any other properties of student that you want to display in the view
  public List<SubjectVM> Subjects { get; set; }
}

视图

@model YourAssembly.StudentVM
@using(Html.BeginForm())
{
  @Html.HiddenFor(m => m.ID)
  @Html.DisplayFor(m => m.Name)
  for(int i = 0; i < Model.Subjects.Count; i++)
  {
    @Html.HiddenFor(m => m.Subjects[i].ID)
    @Html.DisplayFor(m => m.Subjects[i].Name) // will display "General" if no name
    for (int j = 0; j < Model.Subjects[i].Questions.Count; j++)
    {
      @Html.HiddenFor(m => m.Subjects[i].Questions[j].ID)
      @Html.DisplayFor(m => m.Subjects[i].Questions[j].Text)
      foreach(var answer in Model.Subjects[i].Questions[j].PossibleAnswers )
      {
        <div>
          @Html.RadioButtonFor(m => m.Subjects[i].Questions[j].SelectedAnswer, answer.ID, new { id = answer.ID})
          <label for="@answer.ID">@answer.Text</label>
        </div>
      }
      @Html.ValidationMessageFor(m => m.Subjects[i].Questions[j].SelectedAnswer)
    }
  }
  <input type="submit" value="save" />
}

控制者

public ActionResult Edit(int ID)
{
  StudentVM model = new StudentVM();
  // populate your view model with values from the database
  return View(model);
}

[HttpPost]
public ActionResult Edit(StudentVM model)
{
  // save and redirect
}

请注意,我通过你的模型所隐含的数据库结构混淆了一点(比如你为什么需要有单独的模型Question,并SubjectQuestionnull了数值SubjectID将其标识为“一般”的问题)。我建议您首先在GET方法中对一些值进行硬编码,以了解其工作原理并回发。

StudentVM model = new StudentVM();
model.ID = 1;
model.Name = "bambiinela";
model.Subjects = new List<SubjectVM>()
{
  new SubjectVM()
  {
    Questions = new List<QuestionVM>()
    {
      new QuestionVM()
      {
        ID = 1,
        Text = "Question 1",
        SelectedAnswer = ?, // set this if you want to preselect an option
        PossibleAnswers = new List<AnswerVM>()
        {
          new AnswerVM()
          {
            ID = 1,
            Text = "Answer A"
          },
          new AnswerVM()
          {
            ID = 1,
            Text = "Answer B"
          }
        }
      },
      new QuestionVM()
      {
        ID = 2,
        Text = "Question 2",
        PossibleAnswers = new List<AnswerVM>()
        {
          // similar to above
        }
      }
    }
  },
  new SubjectVM()
  {
    ID = 1,
    Name = "Math",
    Questions = new List<QuestionVM>()
    {
      // similar to above
    }
  }
};

发布时,将为模型填充每个主题中每个问题的所选答案的ID。注意DisplayFor()某些属性的使用。这些不会回发,因此如果您返回视图(例如ModelState,无效),则需要重新填充这些属性。或者,您可以生成一个只读文本框或为这些属性添加隐藏的输入。我还建议您检查生成的HTML,尤其是看起来像这样的name属性

<input type="radio" name="Subjects[0].Questions[0].SelectedAnswer" ...

让您了解回发后集合如何绑定到模型

2020-05-19