c# - 从 MVC 4 Web Api 返回匿名类型失败并出现序列化错误

Question

我刚刚开始使用 MVC 4 Web API，我似乎误解了它的工作原理。

在使用 Web API 之前，我有一个像这样的简单 MVC 操作方法:

public JsonResult User()
{
    return Json(new
    {
        firstName = "Joe",
        lastName = "Jacobs",
        email = "joe.jacobs@gmail.com"
    });
}

那会很好。在新的 Web API Controller 中，我正在尝试做类似的事情。

public object User()
{
    return new
    {
        firstName = "Joe",
        lastName = "Jacobs",
        email = "joe.jacobs@gmail.com"
    }
}

由于序列化错误而失败:

The 'ObjectContent`1' type failed to serialize the response body for content type 'application/xml; charset=utf-8'.

内部异常:

Type '<>f__AnonymousType1`3[System.String,System.String,System.String]' cannot be serialized. Consider marking it with the DataContractAttribute attribute, and marking all of its members you want serialized with the DataMemberAttribute attribute. If the type is a collection, consider marking it with the CollectionDataContractAttribute. See the Microsoft .NET Framework documentation for other supported types.

关于从 API Controller 返回匿名类型，我有什么不明白的地方？

Answer 1

如果你看看 Fiddler(这里的例子我用的是 Firefox)

默认情况下，来自浏览器的请求将接受 application/xml，而不是application/json

但是，您可以通过添加一个 header 从 Fiddler 创建假请求:

Accept: application/json

它会起作用

来自link :

The XML serializer does not support anonymous types or JObject instances. If you use these features for your JSON data, you should remove the XML formatter from the pipeline, as described later in this article.

如何删除 XmlFormatter:

  var configuration = GlobalConfiguration.Configuration;
  configuration.Formatters.Remove(configuration.Formatters.XmlFormatter);