json - 在 ASP.NET MVC 3 中将 JSON 反序列化为没有默认构造函数的对象

Question

关于 JSON 反序列化有很多问题，但其中很多似乎是针对 MVC 1 或 MVC 2 的。我似乎没有找到专门针对 MVC 3 的令人满意的答案。

我有一个具有不可变属性且没有默认构造函数的对象，我想在 ASP.NET MVC 3 应用程序中对其进行反序列化。这是一个简化版本:

public class EmailAddress
{
    public EmailAddress(string nameAndEmailAddress)
    {
        Name = parseNameFromNameAndAddress(nameAndEmailAddress);
        Address = parseAddressFromNameAndAddress(nameAndEmailAddress);
    }

    public EmailAddress(string name, string address)
    {
        Guard.Against<FormatException>(!isNameValid(name), "Value is invalid for EmailAddress.Name: [{0}]", name);
        Guard.Against<FormatException>(!isAddressValid(address), "Value is invalid for EmailAddress.Address: [{0}]", address);
        Name = name;
        Address = address;
    }

    public string Address { get; private set; }
    public string Name { get; private set; }

    // Other stuff
}

一个示例 Controller 操作可能是:

[HttpPost]
public ActionResult ShowSomething(EmailAddress emailAddress)
{
    return View(emailAddress)
}

进来的 JSON 是:

{"Address":"joe@bloggs.com","Name":"Joe Bloggs"}

在 MVC3 中反序列化的最佳方法是什么？是否有某种方法可以实现可以处理此问题的自定义模型绑定(bind)器或反序列化器类？

尽管对任何好的建议持开放态度，但不干扰对象本身的解决方案将是可取的(即单独的反序列化器类，而不是向属性添加属性等)。

我在这里发现了一个类似的问题(没有答案):Can I deserialize to an immutable object using JavascriptSerializer?

Answer 1

Is there some way of implementing a custom model binder or deserializer class that can handle this?

是的，您可以编写自定义模型绑定(bind)器:

public class EmailAddressModelBinder : DefaultModelBinder
{
    protected override object CreateModel(ControllerContext controllerContext, ModelBindingContext bindingContext, Type modelType)
    {
        var addressKey = "Address";
        var nameKey = "Name";
        if (!string.IsNullOrEmpty(bindingContext.ModelName))
        {
            addressKey = bindingContext.ModelName + "." + addressKey;
            nameKey = bindingContext.ModelName + "." + nameKey;
        }

        var addressValue = bindingContext.ValueProvider.GetValue(addressKey);
        var nameValue = bindingContext.ValueProvider.GetValue(nameKey);
        if (addressValue == null || nameValue == null)
        {
            throw new Exception("You must supply an address and name");
        }
        return new EmailAddress(nameValue.AttemptedValue, addressValue.AttemptedValue);
    }
}

这将在 Application_Start 中注册:

ModelBinders.Binders.Add(typeof(EmailAddress), new EmailAddressModelBinder());

最后剩下的就是调用 Action :

$.ajax({
    url: '@Url.Action("ShowSomething")',
    type: 'POST',
    data: JSON.stringify({ "Address": "joe@bloggs.com", "Name": "Joe Bloggs" }),
    contentType: 'application/json',
    succes: function (result) {
        alert('success');
    }
});