Asp.net web api 如何使用OData4和WebApi实现无类型实体模型的修补程序？

在使用OData4和WebApi创建一个无类型的实体模型时，我正在为修补程序而挣扎。 我已创建此控制器方法：

[HttpPatch]
public IHttpActionResult Patch([FromODataUri] int key, Delta<EdmEntityObject> delta)
{
  // ...
}

{
  "error": {
    "code": "",
    "message": "The request entity's media type 'application/json' is not supported for this resource.",
    "innererror": {
      "message": "No MediaTypeFormatter is available to read an object of type 'Delta`1' from content with media type 'application/json'.",
      "type": "System.Net.Http.UnsupportedMediaTypeException",
      "stacktrace": "   at System.Net.Http.HttpContentExtensions.ReadAsAsync[T](HttpContent content, Type type, IEnumerable`1 formatters, IFormatterLogger formatterLogger, CancellationToken cancellationToken)\r\n   at System.Web.Http.ModelBinding.FormatterParameterBinding.ReadContentAsync(HttpRequestMessage request, Type type, IEnumerable`1 formatters, IFormatterLogger formatterLogger, CancellationToken cancellationToken)"
    }
  }
}