private void dgvXinXi_MouseClick(object sender, MouseEventArgs e)
        {
            int a = Convert.ToInt32(dgvXinXi.SelectedRows[0].Cells["id"].Value);
            string sql = string.Format("select LeaveCity,Destination,LeaveTime,SecondClass,FirstClass from TicketInfo where Id='{0}'",a);
             try
             {
                 SqlCommand command = new SqlCommand(sql, DBHelper.connection);
                 DBHelper.connection.Open();
                 SqlDataReader datareader = command.ExecuteReader();
                 if (datareader.Read())
                 {
                     txtFrom.Text = datareader["leaveCity"].ToString();
                     txtTo.Text = datareader["Destination"].ToString();
                     txtLeaveTime.Text = datareader["LeaveTime"].ToString();
                     txtJingJi.Text = datareader["SecondClass"].ToString();
                     txtTouDeng.Text = datareader["FirstClass"].ToString();
                 }
                 datareader.Close();
             }
             catch (Exception ex)
             {                 MessageBox.Show(ex.Message);
             }
             finally
             {
                 DBHelper.connection.Close();
             }
大家帮我看下代码,怎么老出现
未能找到名为 id 的列。
参数名: columnName
是什么意思?