xml转dataset如何包含结构信息

Question

如果xml有多层，如下<root>
<item PropName="father">
<item PropName="child" />
</item>
</root>则转到dataset表结构为
item_Id item_Id_0 PropName
0                 father
1       0         child这没问题，但如果XML只有一层，如下<root>
<item PropName="father1"/>
<item PropName="father2" />
</root>则转到dataset表结构为
PropName
father
child少了item_Id item_Id_0两个序号字段
如何让只有一层的XML，转到dataset时也包念两个序号字段
我的转换代码如下
        private static DataSet ConvertXMLToDataSet(string xmlData)
        {
            StringReader stream = null;
            XmlTextReader reader = null;
            try
            {
                DataSet xmlDS = new DataSet();
                stream = new StringReader(xmlData);
                //从stream装载到XmlTextReader                reader = new XmlTextReader(stream);
                xmlDS.ReadXml(reader);
                return xmlDS;
            }
            catch (System.Exception ex)
            {
                throw ex;
            }
            finally
            {
                if (reader != null)
                    reader.Close();
            }
        }

Answer 1

<root>
    <item PropName="father1"/>
    <item PropName="father2" />
</root>
father1和father2都是table

Answer 2

  private static DataSet ConvertXMLToDataSet(string xmlData)
        {
            StringReader stream = null;
            XmlTextReader reader = null;
            try
            {
                DataSet xmlDS = new DataSet();
                stream = new StringReader(xmlData);
                //从stream装载到XmlTextReader                reader = new XmlTextReader(stream);
                xmlDS.ReadXml(reader);
                xmlDS.Tables[0].Columns.Add("item_Id");
                xmlDS.Tables[0].Columns.Add("item_Id_0");
                return xmlDS;
            }
            catch (System.Exception ex)
            {
                throw ex;
            }
            finally
            {
                if (reader != null)
                    reader.Close();
            }
        }
自己添两列... 

Answer 3

如果father1和father2都是table要怎么办呢？