连接本地Access数据库，返回数据集DataSet

        #region 连接本地数据库

        private OleDbConnection con;
        /// <summary>
        /// 打开数据库连接
        /// </summary>
        /// <param name="DBpath">数据库路径(包括数据库名)</param>
        private void Open(String DBpath)
        {
            if (con == null)
                con = new OleDbConnection(@" Provider = Microsoft.Jet.OLEDB.4.0 ; Data Source =C:\Users\yuleyi\Desktop\LocalConfig.mdb");
            if (con.State == ConnectionState.Closed)
                con.Open();
        }

        /// <summary>
        /// 创建一个命令对象并返回该对象
        /// </summary>
        /// <param name="sqlStr">数据库语句</param>
        /// <param name="file">数据库所在路径</param>
        /// <returns>OleDbCommand</returns>
        private OleDbCommand CreateCommand(string sqlStr, string file)
        {
            Open(file);
            OleDbCommand cmd = new OleDbCommand();
            cmd.CommandType = CommandType.Text;
            cmd.CommandText = sqlStr;
            cmd.Connection = con;
            return cmd;
        }

        /// <summary>
        /// 执行数据库查询
        /// </summary>
        /// <param name="sqlStr">查询语句</param>
        /// <param name="tableName">填充数据集表格的名称</param>
        /// <param name="file">数据库所在路径</param>
        /// <returns>查询的数据集</returns>
        public DataSet GetDataSet(string sqlStr, string file)
        {
            DataSet ds = new DataSet();
            OleDbCommand cmd = CreateCommand(sqlStr, file);
            OleDbDataAdapter dataAdapter = new OleDbDataAdapter(cmd);
            dataAdapter.Fill(ds);
            cmd.Dispose();          
            dataAdapter.Dispose();
            return ds;
        }