C#中为XML节点添加属性

    // 设定根节点ItemsCount属性值
    // Parameter：
    //  RootNodeName:根节点名称
    //  ds:数据集
    // Return:
    //      XmlDataDocument
    private XmlDataDocument SetItemsCountAttribute(string strRootNodeName, DataSet ds)
    {
        try
        {
            XmlDataDocument xmlDoc;
            int ItemCount = 0;

            ds.DataSetName = strRootNodeName;
            ds.EnforceConstraints = false;
            if (ds.Tables.Count == 0  )
            {
                xmlDoc = new XmlDataDocument();

                string xml = "<" + strRootNodeName + "></" + strRootNodeName + ">";
                xmlDoc.LoadXml(xml);
            }
            else
            {
                ds.Tables[0].TableName = "Item";

                ItemCount = ds.Tables[0].Rows.Count;
                if (ItemCount == 0)
                {
                    xmlDoc = new XmlDataDocument();

                    string xml = "<" + strRootNodeName + "></" + strRootNodeName + ">";
                    xmlDoc.LoadXml(xml);
                }
                else
                {
                    xmlDoc = new XmlDataDocument(ds);
                }
            }

            XmlNode root = xmlDoc.FirstChild;
            // 创建节点
            XmlNode attrCount = xmlDoc.CreateNode(XmlNodeType.Attribute, "ItemsCount", null);
            attrCount.Value = ItemCount.ToString();
            // 添加节点属性
            root.Attributes.SetNamedItem(attrCount);

            return xmlDoc;
        }
        catch (Exception e)
        {
            string strMsg = e.Message;
            return null;
        }
    }