XML 克隆节点

<?xml version="1.0" encoding="UTF-8"?>
<request>
  <criteriaList>
    <criteria>
      <warehouseCode>仓库编码, string(50), 必填</warehouseCode>
      <ownerCode>货主编码，string(50), 必填</ownerCode>
      <itemCode>商品编码，string(50)，必填</itemCode>
      <itemId>仓储系统商品 ID, string(50)</itemId>
    </criteria>

   <criteria>
      <warehouseCode>仓库编码, string(50), 必填</warehouseCode>
      <ownerCode>货主编码，string(50), 必填</ownerCode>
      <itemCode>商品编码，string(50)，必填</itemCode>
      <itemId>仓储系统商品 ID, string(50)</itemId>
    </criteria>    

  <criteria>
      <warehouseCode>仓库编码, string(50), 必填</warehouseCode>
      <ownerCode>货主编码，string(50), 必填</ownerCode>
      <itemCode>商品编码，string(50)，必填</itemCode>
      <itemId>仓储系统商品 ID, string(50)</itemId>
    </criteria>

  </criteriaList>
</request>

try
            {
                XmlDocument xdi = new XmlDocument();
                xdi.Load(("doc/InventorySync.xml"));//加载出来整个文档
                XmlNode xd = xdi.SelectSingleNode("request/criteriaList/criteria");//要复制的节点，criteria这个节点下还有要复制的字段
                xdi.SelectSingleNode("request/criteriaList").InnerXml = "";//这个是把xml中带有的原有的criteria除去
                for (int i = 0; i < 10; i++)
                {
                    XmlNode xdx = xd.Clone();
                    xdx.SelectSingleNode("warehouseCode").InnerXml = i.ToString();
                    xdx.SelectSingleNode("ownerCode").InnerXml = i.ToString();
                    xdx.SelectSingleNode("itemCode").InnerXml = i.ToString();
                    xdx.SelectSingleNode("itemId").InnerXml = i.ToString();
                    xdi.SelectSingleNode("request/criteriaList").AppendChild(xdx);
                }
            }