内存不足的概念(Out of Memory Concepts)

 HttpResponseMessage<T>在Beta之后被删除。 现在，而不是一个类型化的HttpResponseMessage我们有一个类型化的ObjectContent 
 
 如果使用其默认无参数构造函数手动创建HttpResponseMessage ，则不存在可执行内容协商的请求上下文 - 这就是为什么您需要指定格式化程序或手动执行内容协商的原因。 
 
 我知道你不想那样做 - 所以用它来代替： 
 
HttpResponseMessage response = Request.CreateResponse<MyObject>(HttpStatusCode.OK, objInstance);
 
 这将创建响应消息，依赖于对请求执行的内容协商。 
 
 最后，你可以在这里阅读更多关于内容谈判的链接 

HttpResponseMessage<T> was removed after Beta. Right now, instead of a typed HttpResponseMessage we have a typed ObjectContent
 
If you manually create HttpResponseMessage using its default parameterless constructor, there is no request context available to perform content negotiation - that's why you need to specify the formatter, or perform content negotiation by hand.
 
I understand you don't want to do that - so use this instead:
 
HttpResponseMessage response = Request.CreateResponse<MyObject>(HttpStatusCode.OK, objInstance);
 
That would create the response message relying on the content negotiation performed against the request. 
 
Finally, you can read more about content negotiation here On this link