ASMX 服务错误 - 使用 XmlInclude 或 SoapInclude 属性指定静态未知的类型答案

【问题标题】：ASMX Service Error - Use the XmlInclude or SoapInclude attribute to specify types that are not known staticallyASMX 服务错误 - 使用 XmlInclude 或 SoapInclude 属性指定静态未知的类型
【发布时间】：2020-07-20 08:17:27
【问题描述】：

我有一个带有 Web 方法的 Asmx 服务。在该 Web 方法中，我正在调用一个休息端点（逻辑应用程序端点）。逻辑应用休息终结点接受请求并返回成功 200 响应。

  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);                  
            }

当我点击 client.postasync 行时，我收到以下错误：

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()

【问题讨论】：

标签： c# xml asmx azure-logic-apps

【解决方案1】：

我发现了错误。 webmethod 是异步的，这导致了这个问题。我使web方法返回void并将http客户端post请求代码行更改为：

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

【讨论】：