private void 洱海各月出流流量frm_Load(object sender, EventArgs e)

         {

             //在查询按钮中用下面这段代码会出现打开数据库出错的现象

             MyTable1.Rows.Clear();

             //string msql = "Select 年 as Year order by 年 asc,全年平均 as YearAvr into YearAvrLL from 洱海各月出流流量";//新建表

             string MySQL = "Select * from 洱海各月出流流量 order by 年 asc";

             OleDbConnection MyConnection = new OleDbConnection(MyConnectionString);

             MyConnection.Open();

             OleDbDataAdapter MyAdatper = new OleDbDataAdapter(MySQL, MyConnection);

             //OleDbDataAdapter MyAdatper1 = new OleDbDataAdapter(msql, MyConnection);

             MyAdatper.Fill(MyTable1);

             this.dataGridView1.DataSource = MyTable1;

             if (MyConnection.State == ConnectionState.Open)

             {

                 MyConnection.Close();

             }

         }

         public string MyConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=ErLake.mdb";

         public System.Data.DataTable MyTable1 = new System.Data.DataTable();

         private void 查询_Click(object sender, EventArgs e)

         {

             MyTable1.Rows.Clear();

             string nyr1 = dateTimePicker1.Value.Date.ToString("yyyy-MM-dd");//yyyy-MM-dd正确提取和转换格式，用yyyy-mm-dd格式提取时月份会出错

             string[] tqn1 = nyr1.Split('-');                                //将提取到的yyyy-MM-dd，通过‘-’分割，存入数组

             string nyr2 = dateTimePicker2.Value.Date.ToString("yyyy-MM-dd");//yyyy-MM-dd正确提取和转换格式，用yyyy-mm-dd格式提取时月份会出错

             string[] tqn2 = nyr2.Split('-');                                //将提取到的yyyy-MM-dd，通过‘-’分割

             string sql = "select  * from 洱海各月出流流量 where 年 between '" + tqn1[] + "' and '" + tqn2[] + "' order by 年 asc";//通过修改数据库年字段的数据类型OK，数字类型改为文本类型

             OleDbConnection myCon = new OleDbConnection(MyConnectionString);

             OleDbDataAdapter DA = new OleDbDataAdapter(sql, myCon);

             DA.Fill(MyTable1);

             dataGridView1.DataSource = MyTable1;

         }