将嵌套对象从一个 XmlDocument 复制到另一个 XmlDocument

我在这个问题上很聪明。这是我拥有的文档：

<?xml version="1.0"?>
<TestObject xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Property1>TestObjectVal1</Property1>
  <Property2>TestObjectVal2</Property2>
  <Property3>TestObjectVal3</Property3>
  <SubObject>
    <Prop1>TestObject2Val1</Prop1>
    <Prop2>TestObject2Val2</Prop2>
    <Prop3>TestObject2Val3</Prop3>
  </SubObject>
</TestObject>

我正在尝试将其选择的部分复制到基于某些指定 XPath 的新 XmlDocument 对象。我已经尝试了我能想到的所有排列。这就是我现在所处的位置。

var filters = new[] { "Property1", "Property2", "SubObject/Prop1" };
var xmlDoc = GetObjectXml(obj); //Loads the document
var newDoc = (XmlDocument)xmlDoc.Clone();
newDoc.DocumentElement.RemoveAll(); 
var rootNode = xmlDoc.DocumentElement;
foreach (var filter in filters)
{
    var nodes = rootNode.SelectNodes(filter);
    foreach (XmlNode node in nodes)
    {
        var newNode = newDoc.ImportNode(node, true);
        newDoc.DocumentElement.AppendChild(newNode);
    }
}

我得到的是这样的：

<?xml version="1.0"?>
<TestObject>
  <Property1>TestObjectVal1</Property1>
  <Property2>TestObjectVal2</Property2>
  <Prop1>TestObject2Val1</Prop1>
</TestObject>

但我想要这个：

<?xml version="1.0"?>
<TestObject xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Property1>TestObjectVal1</Property1>
  <Property2>TestObjectVal2</Property2>
  <SubObject>
    <Prop1>TestObject2Val1</Prop1>
  </SubObject>
</TestObject>

知道我做错了什么吗？

foreach (XmlNode node in nodes)
{
    XmlElement newNode; 
    string[] xpathElements = filter.Split('/');
    if (xpathElement.Length == 2) 
    {
        newNode = newDoc.CreateElement(filter);
        newNode.AppendChild(newDoc.ImportNode(node, true));
    }
    else 
    {
        newNode = newDoc.ImportNode(node, true);
    }
    newDoc.DocumentElement.AppendChild(newNode);
}