当我从注释中发现，解决的办法是去除Htt的prequestMessage作为行动参数。这将使API应用程序客户机生成code OK。

As I found out from the comments, the solution is to to remove the HttpRequestMessage as parameter of the Action. This will enable the API App Client to generate the code OK.

如果您需要模拟对象，请遵循的这里或另一个例子的这里。

If you need to mock the object, please follow the documented way from here or another example here.