xml問題 - .NET技术 / C#

需要生成如下XML文件，請幫忙
<HubStorage>
<SEQNUM>20100506</SEQNUM>
<StorageItem HubName="DBN" VendorCode="DDY" Materials="DD0SY2LC000" State="1" Lfimg="0" Minpcs="10" /> 
<StorageItem HubName="DBN" VendorCode="DDY" Materials="DD0GD3LC000" State="1" Lfimg="20" Minpcs="10" /> 
</HubStorage>

---

C# code:
class Program
{
static void Main(string[] args)
{
Console.Write(CreateXML());
Console.ReadKey();
}

private static string CreateXML()
{
try
{
XmlDocument doc = new XmlDocument();
XmlElement rootNode = doc.CreateElement("HubStorage");
doc.AppendChild(rootNode);
XmlElement seqnum = doc.CreateElement("SEQNUM");
seqnum.InnerText = "20100506";
rootNode.AppendChild(seqnum);
XmlElement storeNode1 = doc.CreateElement("StorageItem");
storeNode1.SetAttribute("HubName", "DBN");
storeNode1.SetAttribute("VendorCode", "DDY");
st