ASP.NET MVC3绑定到子类 [英] ASP.NET MVC3 bind to subclass

问题描述

我有型的问题的具有多个子类的父类（如 MultipleChoiceQuestion 的和的 TextQuestion 的）。每个子类中有自己的编辑模板（例如〜/共享/ EditorTemplates / MultipleChoiceQuestion.cshtml 的）。

I have a superclass of type Question which has multiple subclasses (e.g. MultipleChoiceQuestion and TextQuestion). Each of the subclasses have their own editor templates (e.g. ~/Shared/EditorTemplates/MultipleChoiceQuestion.cshtml).

我想这样做的就是创建一个列表的问题的对象：

What I would like to do is create a list of Question objects:

class Questionnaire {
    List<Question> Questions;
}

这将真正包含子类的实例：

which will really contain instances of the subclasses:

Questions.Add(new MultipleChoiceQuestion());
Questions.Add(new TextQuestion());

然后我问卷传递给视图，在这里我呼吁：

I then pass the questionnaire to the View, where I call:

@Html.EditorFor(m => m.Questions)

该视图呈现成功的具体子类的问题的模型。

问题是，当表单提交，我的问卷的模型（其中包含类型的列表的问题的）包含的问题而不是子类的实例。 。此外实例的问题的属性都为空。

The problem is that when the form is submitted, my Questionnaire model (which contains a list of type Question) contains only instances of Question and not the instances of the subclasses. Furthermore the instances of Question properties are all null.

作为测试，我在类型的列表通过的 MultipleChoiceQuestion 的和正常工作：

As a test, I have passed in a list of type MultipleChoiceQuestion and it works fine:

class Questionnaire {
    List<MultipleChoiceQuestion> Questions;
}

有什么方法可以让我得到HttpPost行动来回报我与我的表单数据实例化的子类的模式？

Is there any way I can get the HttpPost Action to return my model with the subclasses instantiated with my form data?

感谢

推荐答案

我认为你对DefaultModelBinder的限制运行起来。为了解决这个问题，你需要使用一个客户模型绑定。

I think you're running up against a limitation of the DefaultModelBinder. To solve this problem, you need to use a customer model binder.

您可能会发现这个帖子一个有用的指南;它谈论这个特定的问题。

You might find this post a useful guide; it talks about this specific problem.

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