Create New XML File

Dim tmpXml As New Xml.XmlDocument
        Dim tmpNode As Xml.XmlNode
        Dim subNode As Xml.XmlNode
        Dim g_XmlDoc As New Xml.XmlDocument

        '初始化XML
        tmpXml.LoadXml("<?xml version=""1.0"" encoding=""GB2312""?><Root></Root>")

        '添加用户信息节点"
        tmpNode = tmpXml.CreateNode(Xml.XmlNodeType.Element, "User", Nothing)
        subNode = tmpXml.CreateNode(Xml.XmlNodeType.Element, "UserID", Nothing)
        subNode.InnerText = "uid"
        subNode = tmpXml.CreateNode(Xml.XmlNodeType.Element, "UserName", Nothing)
        subNode.InnerText = "uname"
        tmpNode.AppendChild(subNode)
        tmpXml.DocumentElement.AppendChild(tmpNode)

        '添加用户信息节点
        tmpNode = tmpXml.CreateNode(Xml.XmlNodeType.Element, "Shop", Nothing)
        subNode = tmpXml.CreateNode(Xml.XmlNodeType.Element, "ShopID", Nothing)
        subNode.InnerText = "shopid"
        tmpNode.AppendChild(subNode)
        subNode = tmpXml.CreateNode(Xml.XmlNodeType.Element, "ShopName", Nothing)
        subNode.InnerText = "test"
        tmpNode.AppendChild(subNode)

        tmpXml.DocumentElement.AppendChild(tmpNode)
        tmpXml.Save("text.xml")
        MsgBox("ok")

RESULT:

<?xml version="1.0" encoding="GB2312"?>
<Root>
  <User>
    <UserName>uname</UserName>
  </User>
  <Shop>
    <ShopID>shopid</ShopID>
    <ShopName>test</ShopName>
  </Shop>
</Root>

C#
 XmlDocument xmlDoc = new XmlDocument();
        XmlNode titleNode = null;
        XmlNode sortNode = null;
        XmlNode dateNode = null;
        XmlNode contentNode = null;
        
        string xmlStr = "<?xml version='1.0' encoding='GB2312'?>";
        xmlStr += "<?xml-stylesheet type='text/xsl' href='new.xsl'?><News></News>";
        xmlDoc.LoadXml(xmlStr);

        titleNode = xmlDoc.CreateNode(XmlNodeType.Element, "Title", null);
        titleNode.InnerText = "titleNode_value";
        xmlDoc.DocumentElement.AppendChild(titleNode);

        sortNode = xmlDoc.CreateNode(XmlNodeType.Element, "SortName", null);
        sortNode.InnerText = "sortName_value";
        xmlDoc.DocumentElement.AppendChild(sortNode);

        dateNode = xmlDoc.CreateNode(XmlNodeType.Element, "Date", null);
        dateNode.InnerText = "2007-05-30";
        xmlDoc.DocumentElement.AppendChild(dateNode);

        contentNode = xmlDoc.CreateNode(XmlNodeType.Element, "Content", null);
        contentNode.InnerText = "content_value";
        xmlDoc.DocumentElement.AppendChild(contentNode);

        xmlDoc.Save(Server.MapPath("xml\\news2.xml"));

        Response.Write("ok");

Result
<?xml version="1.0" encoding="GB2312"?>
<?xml-stylesheet type='text/xsl' href='news.xsl'?>
<News>
  <Title>titleNode_value</Title>
  <SortName>sortName_value</SortName>
  <Date>2007-05-30</Date>
  <Content>content_value</Content>
</News>