ASMX 服務錯誤 - 使用 XmlInclude 或 SoapInclude 屬性指定靜態未知的類型

Question

我有一個帶有 web 方法的 Asmx 服務。 在該 web 方法中，我正在調用 rest 端點（邏輯應用程序端點）。 邏輯應用 rest 端點接受請求並返回成功 200 響應。

  using (var client = new HttpClient())
            {
                client.BaseAddress = new Uri("base address");
                var content = new StringContent(JsonConvert.SerializeObject(request, Formatting.Indented), Encoding.UTF8, "application/json");
                var result = await client.PostAsync("some-uri", content);                  
            }

一旦我點擊 client.postasync 行，我就會收到以下錯誤：

System.InvalidOperationException: There was an error generating the XML document. ---> System.InvalidOperationException: The type System.Threading.Tasks.Task`1[[System.Threading.Tasks.VoidTaskResult, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]] was not expected. Use the XmlInclude or SoapInclude attribute to specify types that are not known statically.
   at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationWriter1.Write2_Task(String n, String ns, Task o, Boolean isNullable, Boolean needType)
   at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationWriter1.Write3_Task(Object o)
   at Microsoft.Xml.Serialization.GeneratedAssembly.TaskSerializer.Serialize(Object objectToSerialize, XmlSerializationWriter writer)
   at System.Xml.Serialization.XmlSerializer.Serialize(XmlWriter xmlWriter, Object o, XmlSerializerNamespaces namespaces, String encodingStyle, String id)
   --- End of inner exception stack trace ---
   at System.Xml.Serialization.XmlSerializer.Serialize(XmlWriter xmlWriter, Object o, XmlSerializerNamespaces namespaces, String encodingStyle, String id)
   at System.Xml.Serialization.XmlSerializer.Serialize(TextWriter textWriter, Object o, XmlSerializerNamespaces namespaces)
   at System.Web.Services.Protocols.XmlReturnWriter.Write(HttpResponse response, Stream outputStream, Object returnValue)
   at System.Web.Services.Protocols.HttpServerProtocol.WriteReturns(Object[] returnValues, Stream outputStream)
   at System.Web.Services.Protocols.WebServiceHandler.WriteReturns(Object[] returnValues)
   at System.Web.Services.Protocols.WebServiceHandler.Invoke()

Answer 1

我發現了錯誤。 webmethod 是異步的，這導致了這個問題。 我使 web 方法返回 void 並將 http 客戶端發布請求代碼行更改為以下代碼：

  var result = client.PostAsync(reqUri, requestContent).GetAwaiter().GetResult();