private void Form1_load(object sender, EventArgs e)//窗体加载事件
        {
            //调用查询全部资料的方法
            QueryAllCourse();

        }
        private void QueryAllCourse()//显示的方法
        {
            string Con = "provider=MIcrosoft.ACE.OLEDB.12.0;" + @"Data source=D:\c\DataBase\student.accdb";//第二个参数为文件的路径  
            OleDbConnection conn = null;
            try
            {
                 conn = new OleDbConnection(Con);
                conn.Open();//建立连接
                OleDbDataAdapter inst = new OleDbDataAdapter("SELECT * FROM student", conn);//选择全部内容

                DataSet ds = new DataSet();//临时存储
                inst.Fill(ds);//用inst填充ds
                dataGridView1.DataSource = ds.Tables[0];//展示ds第一张表到dataGridView1控件

                dataGridView1.Columns[0].HeaderText = "学号";
                dataGridView1.Columns[1].HeaderText = "学生姓名";
                dataGridView1.Columns[2].HeaderText = "年龄";
                dataGridView1.Columns[3].HeaderText = "身高";
                dataGridView1.Columns[4].HeaderText = "性别"; //设置数据表格上显示的列标题

                dataGridView1.ReadOnly = true;     //设置表格只读属性
                dataGridView1.AllowUserToAddRows = false;//不允许添加行
                dataGridView1.BackgroundColor = Color.White;//背景色为白色
                dataGridView1.MultiSelect = false;//只允许选中单行
                dataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect;//整行选中
            }
            catch(Exception ex)
            {
                MessageBox.Show("查询错误" + ex.Message);
            }
           finally
                {
                if(conn!=null)
                {
                    conn.Close();
                }

这是c

我查询可以，就是把查询放到窗体加载事件不行！