用C#创建一个xml文件，自定义的xmlns没有写到元素当中去，为什么?

[nsareio]

我有下面一段代码:

    class Program
    {
        static void Main(string[] args)
        {
            XmlDocument document = new XmlDocument();
            document.AppendChild(document.CreateXmlDeclaration("1.0", "UTF-8", ""));
            XmlNamespaceManager manager = new XmlNamespaceManager(document.NameTable);
            //manager.AddNamespace("haha", "http://schemas.microsoft.com/BizTalk/2003");
            XmlElement root = document.CreateElement("my:root", "haha:http://schemas.microsoft.com/BizTalk/2003");
            document.AppendChild(root);

            XmlElement newNode = document.CreateElement("abc","my");
            newNode.InnerText = "hello";
            root.AppendChild(newNode);
            XmlElement newNode1 = document.CreateElement("xyz","my");
            newNode1.InnerText = "world";
            root.AppendChild(newNode1);
            document.Save(@"d:\test.xml");
        }
    }

运行的结果是产生了一个xml，但是有点不符合我的预期

<?xml version="1.0" encoding="UTF-8"?>
<my:root xmlns:my="haha:http://schemas.microsoft.com/BizTalk/2003"> 
<abc xmlns="my">hello</abc>
<xyz xmlns="my">world</xyz>
 </my:root>

而我期待的是内嵌的两个元素是

  <my:abc>hello</my:abc>
   <my:xyz>world</my:xyz>

看起来我的C#代码在写入abc和xyz这两个tag的时候，是用了xmlnm="my"这样的写法。
(1)这个写法和my:abc的效果是一样的吗? 还是有所不同呢?
(2)如果我希望代码生成my:abc这样的标签，代码改怎么改?

[nsareio]

自己顶起来一下!

[dalmeeme]

		XmlDocument document = new XmlDocument();
		document.AppendChild(document.CreateXmlDeclaration("1.0", "UTF-8", ""));
		string namespaceUrl = "haha:http://schemas.microsoft.com/BizTalk/2003";
		XmlElement root = document.CreateElement("my", "root", namespaceUrl);
		document.AppendChild(root);
		XmlElement newNode = document.CreateElement("my", "abc", namespaceUrl);
		newNode.InnerText = "hello";
		root.AppendChild(newNode);
		XmlElement newNode1 = document.CreateElement("my", "xyz", namespaceUrl);
		newNode1.InnerText = "world";
		root.AppendChild(newNode1);
		document.Save(@"d:\test.xml");

最后得到：

<?xml version="1.0" encoding="UTF-8" ?> 
 <my:root xmlns:my="haha:http://schemas.microsoft.com/BizTalk/2003">
  <my:abc>hello</my:abc> 
  <my:xyz>world</my:xyz> 
  </my:root>