using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Xml.Serialization;
using System.IO;

namespace dst
{
    public class dst026
    {
        /// <summary>
        /// XMLファイルを逆シリアライズしDataTableオブジェクトで返します。
        /// </summary>
        /// <param name="dt">DataTableオブジェクト</param>
        /// <param name="xmlPath">XMLファイルパス</param>
        static public void LoadXMLToDataTable(ref DataTable dt, string xmlPath)
        {
            using (FileStream fs = new FileStream(xmlPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
            {
                XmlSerializer serializer = new XmlSerializer(dt.GetType());
                dt = (DataTable)serializer.Deserialize(fs);
            }
        }
    }
}

private void button2_Click(object sender, EventArgs e)
{
    DataTable dt = new DataTable();
    dst026.LoadXMLToDataTable(ref dt, "dst025.xml");
}