Why the XmlInclude does not work in my project?[Answered] RSS

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  mywatermelon

  Member

  53 Points

  246 Posts

  Why the XmlInclude does not work in my project?

  Sep 22, 2019 08:10 AM|mywatermelon|LINK

  I override the Serialize for removing the prefix of XML:

  Here is the startup.cs:

  services.AddMvc(options =>
              {
                  options.OutputFormatters.Add(new Classes.XmlSerializerOutputFormatterNamespace());
              })
  
  

  And here is the code of override Serialize:

  public class XmlSerializerOutputFormatterNamespace : XmlSerializerOutputFormatter
      {
          protected override void Serialize(XmlSerializer xmlSerializer, XmlWriter xmlWriter, object value)
          {
              //applying "empty" namespace will produce no namespaces
              var emptyNamespaces = new XmlSerializerNamespaces();
              emptyNamespaces.Add("", "any-non-empty-string");
              xmlSerializer.Serialize(xmlWriter, value, emptyNamespaces);
          }
      }

  And here is the code of controller:

          [HttpPost]
          [Produces("application/xml")]
          public async Task<BaseMsg> mp([FromBody]TextMsg XmlData)
          {
              TextMsg ReturnXmlData = new TextMsg() { ToUserName = XmlData.FromUserName, FromUserName = XmlData.ToUserName ,CreateTime= XmlData.CreateTime, MsgType= "text", Content ="你好呀"};                        
              return ReturnXmlData;
          }
          [XmlInclude(typeof(BaseMsg))]
          [XmlRoot("xml")]
          public class BaseMsg {
              public string ToUserName { get; set; }
              public string FromUserName { get; set; }
              public string CreateTime { get; set; }
              public string MsgType { get; set; }
              public string MsgId { get; set; }
          }
          [XmlInclude(typeof(TextMsg))]
          [XmlRoot("xml")]
          public class TextMsg:BaseMsg {
              
              public string Content { get; set; }
          }

  After I ran the program and send a post, Visual Studio reports an error in the override Serialize:

  System.InvalidOperationException: 'There was an error generating the XML document.'

  InvalidOperationException: The type Demo.Controllers.CallbackController+TextMsg was not expected. Use the XmlInclude or SoapInclude attribute to specify types that are not known statically.

  It seems reported this error for I did not use the XmlInclude. However, as you see I added it yet and why I did not work yet?

  I tried some ways and found if I don't inherit the BaseMsg class, it won't report this anymore.

  Why it turns out to be this? Would you please help me? Thank you.

• • Reply
  Rena Ni

  Contributor

  2690 Points

  874 Posts

  Re: Why the XmlInclude does not work in my project?

  Sep 23, 2019 02:25 AM|Rena Ni|LINK

  Hi mywatermelon,

  You need to remove the following attribute in the TextMsg class:

  [XmlInclude(typeof(TextMsg))]

  And then modify the attribute in BaseMsg class like below:

      [XmlInclude(typeof(TextMsg))]
      [XmlRoot("xml")]
      public class BaseMsg
      {
          public string ToUserName { get; set; }
          public string FromUserName { get; set; }
          public string CreateTime { get; set; }
          public string MsgType { get; set; }
          public string MsgId { get; set; }
      }

  Reference: http://www1.cs.columbia.edu/~lok/csharp/refdocs/System.Xml.Serialization/types/XmlIncludeAttribute.html

  Best Regards,

  Rena

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• • Reply
  mywatermelon

  Member

  53 Points

  246 Posts

  Re: Why the XmlInclude does not work in my project?

  Sep 23, 2019 02:26 AM|mywatermelon|LINK

  Thanks a lot.