Serializing object with no namespaces using DataContractSerializer

Question

How do I remove XML namespaces from an object's XML representation serialized using DataContractSerializer?

That object needs to be serialized to a very simple output XML.

• Latest & greatest - using .Net 4 beta 2
• The object will never need to be deserialized.
• XML should not have any xmlns:... namespace refs
• Any subtypes of Exception and ISubObject need to be supported.
• It will be very difficult to change the original object.

Object:

 [Serializable]   class MyObj  {      string str;      Exception ex;      ISubObject subobj;  }  

Need to serialize into:

<xml>   <str>...</str>   <ex i:nil="true" />   <subobj i:type="Abc">      <AbcProp1>...</AbcProp1>      <AbcProp2>...</AbcProp2>   </subobj> </xml> 

I used this code:

private static string ObjectToXmlString(object obj) {     if (obj == null) throw new ArgumentNullException("obj");      var serializer =         new DataContractSerializer(             obj.GetType(), null, Int32.MaxValue, false, false, null,             new AllowAllContractResolver());      var sb = new StringBuilder();     using (var xw = XmlWriter.Create(sb, new XmlWriterSettings     {         OmitXmlDeclaration = true,         NamespaceHandling = NamespaceHandling.OmitDuplicates,         Indent = true     }))     {         serializer.WriteObject(xw, obj);         xw.Flush();          return sb.ToString();     } } 

From this article I adopted a DataContractResolver so that no subtypes have to be declared:

public class AllowAllContractResolver : DataContractResolver {     public override bool TryResolveType(Type dataContractType, Type declaredType, DataContractResolver knownTypeResolver, out XmlDictionaryString typeName, out XmlDictionaryString typeNamespace)     {         if (!knownTypeResolver.TryResolveType(dataContractType, declaredType, null, out typeName, out typeNamespace))         {             var dictionary = new XmlDictionary();             typeName = dictionary.Add(dataContractType.FullName);             typeNamespace = dictionary.Add(dataContractType.Assembly.FullName);         }         return true;     }      public override Type ResolveName(string typeName, string typeNamespace, Type declaredType, DataContractResolver knownTypeResolver)     {         return knownTypeResolver.ResolveName(typeName, typeNamespace, declaredType, null) ?? Type.GetType(typeName + ", " + typeNamespace);     } } 

Answer 1

You need to mark the classes you want to serialize with:

[DataContract(Namespace="")] 

In that case, the data contract serializer will not use any namespace for your serialized objects.

Marc

Answer 2

If you have your heart set on bypassing the default behavior (as I currently do), you create a custom XmlWriter that bypasses writing the namespace.

using System.IO; using System.Xml;  public class MyXmlTextWriter : XmlTextWriter {   public MyXmlTextWriter(Stream stream)     : base(stream, null)   {   }    public override void WriteStartElement(string prefix, string localName, string ns)   {     base.WriteStartElement(null, localName, "");   } } 

Then in your writer consumer, something like the following:

var xmlDoc = new XmlDocument(); DataContractSerializer serializer = new DataContractSerializer(obj.GetType()); using (var ms = new MemoryStream()) {   using (var writer = new MyXmlTextWriter(ms))   {     serializer.WriteObject(writer, obj);     writer.Flush();     ms.Seek(0L, SeekOrigin.Begin);     xmlDoc.Load(ms);   } } 

And the output will have namespace declarations in it, but there will be no usages as such:

<TestObject xmlns:i="http://www.w3.org/2001/XMLSchema-instance">   <Items xmlns:d2p1="http://schemas.microsoft.com/2003/10/Serialization/Arrays">     <string>Item1</string>     <string>Item2</string>   </Items> </TestObject>