Serialization of class (object) into XML SOAP results in error-CodePudding

  XmlTypeMapping myTypeMapping = new SoapReflectionImporter().ImportTypeMapping(typeof(AddressValidationRequest));
XmlSerializer serializer = new XmlSerializer(myTypeMapping);
TextWriter writer = new StreamWriter(filename);

serializer.Serialize(writer, request);
writer.Close();

I am trying to serialize a class into XML (SOAP). I keep receiving the error message below. Does anyone know why this might be happening?

System.InvalidOperationException: 'There was an error generating the XML document.'
InvalidOperationException: Token StartElement in state Epilog would result in an invalid XML document.

System.InvalidOperationException
  HResult=0x80131509
  Message=There was an error generating the XML document.
  Source=System.Private.Xml
  StackTrace:
   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.Xml.Serialization.XmlSerializer.Serialize(TextWriter textWriter, Object o)

  This exception was originally thrown at this call stack:
    System.Xml.XmlTextWriter.AutoComplete(System.Xml.XmlTextWriter.Token)
    System.Xml.XmlTextWriter.WriteStartElement(string, string, string)
    System.Xml.Serialization.XmlSerializationWriter.WriteStartElement(string, string, object, bool, System.Xml.Serialization.XmlSerializerNamespaces)
    System.Xml.Serialization.XmlSerializationWriter.WriteArray(string, string, object, System.Type)
    System.Xml.Serialization.XmlSerializationWriter.WriteReferencedElement(string, string, object, System.Type)
    System.Xml.Serialization.XmlSerializationWriter.WriteReferencedElements()
    System.Xml.Serialization.ReflectionXmlSerializationWriter.GenerateTypeElement(object, System.Xml.Serialization.XmlTypeMapping)
    System.Xml.Serialization.ReflectionXmlSerializationWriter.WriteObject(object)
    System.Xml.Serialization.XmlSerializer.SerializeUsingReflection(System.Xml.XmlWriter, object, System.Xml.Serialization.XmlSerializerNamespaces, string, string)
    System.Xml.Serialization.XmlSerializer.Serialize(System.Xml.XmlWriter, object, System.Xml.Serialization.XmlSerializerNamespaces, string, string)

Inner Exception 1:
InvalidOperationException: Token StartElement in state Epilog would result in an invalid XML document.

CodePudding user response：

Use XmlTextWriter instead of TextWriter and do a writer.WriteStartElement("wrapper"):

XmlTypeMapping myTypeMapping = new SoapReflectionImporter().ImportTypeMapping(typeof(AddressValidationRequest));
XmlSerializer serializer = new XmlSerializer(myTypeMapping);
XmlTextWriter writer = new XmlTextWriter(filename, System.Text.Encoding.UTF8);
writer.Formatting = System.Xml.Formatting.Indented;
writer.WriteStartElement("wrapper");                      
serializer.Serialize(writer, request);
writer.WriteEndElement();
writer.Close();

Reference:

https://docs.microsoft.com/en-us/dotnet/api/system.xml.serialization.soapreflectionimporter?view=net-6.0#examples