多种文件做数据源的连接方法

下面有详细方法:
http://www.connectionstrings.com/default.aspx
导入的文件下必须有一个命名为"Schema.ini"的配置文件，如何配置，上面的网址里有详细说明.
如下示例:

string dir=Path.GetDirectoryName(filePath);
        string filename=Path.GetFileName(filePath);
        string conStr = string.Format("Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0}\\;Extended Properties=\"text;HDR=Yes;FMT=Delimited(,)\";", dir);
        using (OleDbConnection oledbCon = new OleDbConnection(conStr))
        {
            OleDbDataReader reader=null;
            OleDbCommand oledbCom = new OleDbCommand();
            oledbCom.Connection = oledbCon;
            oledbCom.CommandText = string.Format("select top 1 * from {0}", filename);

            try
            {
                oledbCon.Open();
                reader = oledbCom.ExecuteReader();            }
            catch (SqlException e)
            {
                throw new Exception(e.Message);
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }
            finally
            {
                if (reader != null)
                {
                    reader.Close();
                }
            }
        }