XML与DataSet相互转换，DataSet查询

以FileShare.Read形式读XML文件:

string hotspotXmlStr = string.Empty;
try
{
    Stream fileStream = new FileStream(context.Server.MapPath("../data/Hotspot.xml"), FileMode.Open, FileAccess.Read, FileShare.Read);
    StreamReader streamReader = new StreamReader(fileStream, Encoding.UTF8);
    hotspotXmlStr = streamReader.ReadToEnd();
    streamReader.Dispose();
}
catch (Exception ex)
{
    logger.Error("读取XML文件Hotspot.xml出现异常！");
    logger.Error("异常描述：	" + ex.Message);
    logger.Error("引发异常的方法：	" + ex.TargetSite);
    logger.Error("异常堆栈：	" + ex.StackTrace);
}

XML与DataSet相互转换的类（出处）：

class XmlDatasetConvert
{
    //将xml对象内容字符串转换为DataSet
    public 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();
        }
    }

    //将xml文件转换为DataSet
    public static DataSet ConvertXMLFileToDataSet(string xmlFile)
    {
        StringReader stream = null;
        XmlTextReader reader = null;
        try
        {
            XmlDocument xmld = new XmlDocument();
            xmld.Load(xmlFile);

            DataSet xmlDS = new DataSet();
            stream = new StringReader(xmld.InnerXml);
            //从stream装载到XmlTextReader
            reader = new XmlTextReader(stream);
            xmlDS.ReadXml(reader);
            //xmlDS.ReadXml(xmlFile);
            return xmlDS;
        }
        catch (System.Exception ex)
        {
            throw ex;
        }
        finally
        {
            if (reader != null) reader.Close();
        }
    }

    //将DataSet转换为xml对象字符串
    public static string ConvertDataSetToXML(DataSet xmlDS)
    {
        MemoryStream stream = null;
        XmlTextWriter writer = null;

        try
        {
            stream = new MemoryStream();
            //从stream装载到XmlTextReader
            writer = new XmlTextWriter(stream, Encoding.Unicode);

            //用WriteXml方法写入文件.
            xmlDS.WriteXml(writer);
            int count = (int)stream.Length;
            byte[] arr = new byte[count];
            stream.Seek(0, SeekOrigin.Begin);
            stream.Read(arr, 0, count);

            UnicodeEncoding utf = new UnicodeEncoding();
            return utf.GetString(arr).Trim();
        }
        catch (System.Exception ex)
        {
            throw ex;
        }
        finally
        {
            if (writer != null) writer.Close();
        }
    }

    //将DataSet转换为xml文件
    public static void ConvertDataSetToXMLFile(DataSet xmlDS, string xmlFile)
    {
        MemoryStream stream = null;
        XmlTextWriter writer = null;

        try
        {
            stream = new MemoryStream();
            //从stream装载到XmlTextReader
            writer = new XmlTextWriter(stream, Encoding.Unicode);

            //用WriteXml方法写入文件.
            xmlDS.WriteXml(writer);
            int count = (int)stream.Length;
            byte[] arr = new byte[count];
            stream.Seek(0, SeekOrigin.Begin);
            stream.Read(arr, 0, count);

            //返回Unicode编码的文本
            UnicodeEncoding utf = new UnicodeEncoding();
            StreamWriter sw = new StreamWriter(xmlFile);
            sw.WriteLine("<?xml version="1.0" encoding="utf-8"?>");
            sw.WriteLine(utf.GetString(arr).Trim());
            sw.Close();
        }
        catch (System.Exception ex)
        {
            throw ex;
        }
        finally
        {
            if (writer != null) writer.Close();
        }
    }

}

 DataSet查询，参考DataTable.Select 方法。