asp.net 读取Excle 兼容2007

    //将指定excel文件中的数据转换成DataTable    /// <summary>    /// 将指定excel文件中的数据转换成DataTable对象，供应用程序进一步处理    /// </summary>    /// <param name="filepath">文件路径</param>    /// <returns></returns>    public static DataTable import(string filepath)    {        DataTable rs = new DataTable();        bool canopen = false;        // 数据连接  HDR=Yes;IMEX=1;        OleDbConnection conn = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Persist Security Info=False;" +            "Data Source=" + filepath.ToString() + ";" +            "Extended Properties='Excel 8.0;IMEX=1'");

        try//尝试数据连接是否可用        {            conn.Open();            conn.Close();            canopen = true;        }        catch { }

        if (canopen)        {            try//如果数据连接可以打开则尝试读入数据            {                OleDbCommand myoledbcommand = new OleDbCommand("select * from [sheet1$]", conn);                OleDbDataAdapter mydata = new OleDbDataAdapter(myoledbcommand);                mydata.Fill(rs);                conn.Close();            }            catch//如果数据连接可以打开但是读入数据失败，则从文件中提取出工作表的名称，再读入数据            { //获取文件的工作表名                string sheetname = getsheetname(filepath);                if (sheetname.Length > 0)                {                    OleDbCommand myoledbcommand = new OleDbCommand("select * from [" + sheetname + "$]", conn);                    OleDbDataAdapter mydata = new OleDbDataAdapter(myoledbcommand);                    mydata.Fill(rs);                    conn.Close();                }            }        }        else        { // 如果oledb不能连接，就读取文件到流              StreamReader tmpstream;//=File.OpenText(filepath);               tmpstream = new StreamReader(filepath, System.Text.Encoding.GetEncoding("gb2312"));            string tmpstr = tmpstream.ReadToEnd();            tmpstream.Close();            // 过滤表中内容的html字符            rs = getdatatablefromstring(tmpstr);            tmpstr = "";        }        return rs;    }