/// <summary>
        /// 对连接的数据库执行响应的处理指令
        /// </summary>
        /// <param name="connectStr"> 定义的数据库连接字符串 </param>
        /// <param name="sqlStr"> 要执行的SQL指令 </param>
        private void sqlCmd(string connectStr, string sqlStr)
        {
            OleDbConnection conn = new OleDbConnection(connectStr);
            try
            {
                conn.Open();//注意增删改查的代码均插入在该行代码之后
                OleDbCommand comm = conn.CreateCommand();
                comm.CommandText = sqlStr;
                comm.Connection = conn;
                //这句话位置只能放在这里，不能前边
                comm.ExecuteNonQuery();
                comm.Dispose();
                conn.Close();
            }
            catch (Exception ee)
            {
                MessageBox.Show(ee.Message.ToString());
            }
            finally
            {
                conn.Close();
            }
        }

        private void clearDataTable_Click(object sender, EventArgs e)
        {
            string txtConn =
            @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=E:\C#\Example200\AccessLearn\AccessLearn\bin\Debug\myExcise.mdb";
            //删除数据表中所有数据
            string strcomm = "delete * from table1";
            sqlCmd(txtConn, strcomm); 
            //重置ID从1开始
            string strIter = "Alter TABLE table1 Alter COLUMN ID COUNTER (1, 1)";
            sqlCmd(txtConn, strIter);
        }