去掉XML命名空间及声明头不影响反序列化，

int obj = 1;
XmlSerializer serializer = new XmlSerializer(obj.GetType());

// 将对象序列化输出到文件
FileStream stream = new FileStream("hh.xml", FileMode.Create);

XmlWriterSettings settings = new XmlWriterSettings();
settings.Indent = true;
settings.IndentChars = "    ";
settings.NewLineChars = "\r\n";
settings.Encoding = Encoding.UTF8;
//settings.OmitXmlDeclaration = true;  // 不生成声明头

using (XmlWriter xmlWriter = XmlWriter.Create(stream, settings))
{
    // 强制指定命名空间，覆盖默认的命名空间
    XmlSerializerNamespaces namespaces = new XmlSerializerNamespaces();
    namespaces.Add(string.Empty, string.Empty);
    serializer.Serialize(xmlWriter, obj, namespaces);
    xmlWriter.Close();
};
stream.Close();