在使用DataContractResolver序列化接口时过于冗长的XML

Question

我已经大大缩短了这个问题，因为到目前为止我还没有得到任何答案。

基本上我正在尝试使用DataContractSerializer序列化接口。但是当使用DataContractResolver执行此操作时，生成的XML实际上非常详细。我有一个接口IAnimal和一个具体的实现Cat。

如果我只是序列化Cat，我会得到XML：

<Cat xmlns="http://schemas.datacontract.org/2004/07/TestDataContractResolver.Concrete" xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
  <Species>feline</Species>
  <Weight>1</Weight>
</Cat>

但是，在DataContractResolver的帮助下序列化IAnimal时，我得到以下XML：

<z:anyType i:type="a:TestDataContractResolver.Concrete.Cat" xmlns:z="http://schemas.microsoft.com/2003/10/Serialization/" xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns:a="TestDataContractResolver.Concrete, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null">
  <Species xmlns="http://schemas.datacontract.org/2004/07/TestDataContractResolver.Concrete">feline</Species>
  <Weight xmlns="http://schemas.datacontract.org/2004/07/TestDataContractResolver.Concrete">1</Weight>
</z:anyType>

这是冗长冗长的。为什么它会将xmlns粘贴到每个属性元素中，而不仅仅是根元素？我怎么能不这样做呢？

顺便说一句，这是基于Youssef Moussaoui's blog的DataContractSerializer的实现：

public class ModelDataContractResolver : DataContractResolver
    {
        public override Type ResolveName(string typeName, string typeNamespace, Type declaredType, DataContractResolver knownTypeResolver)
        {
            return knownTypeResolver.ResolveName(typeName, typeNamespace, declaredType, null) ?? Type.GetType(typeName + ", " + typeNamespace);
        }

        public override bool TryResolveType(Type type, Type declaredType, DataContractResolver knownTypeResolver, out XmlDictionaryString typeName, out XmlDictionaryString typeNamespace)
        {
            if (knownTypeResolver.TryResolveType(type, declaredType, null, out typeName, out typeNamespace))
            {
                return true;
            }

            XmlDictionary dictionary = new XmlDictionary();
            typeName = dictionary.Add(type.FullName);
            typeNamespace = dictionary.Add(type.Assembly.FullName);

            return true;
        }
    }