private void Load_BTN_Click(object sender, EventArgs e)
    {


           try
         {

             string selectQuery = "Select * from  Fuel_Attendend";
             cmd = new SqlCommand(selectQuery, connection);
        try
        {
            connection.Open();
            dr = cmd.ExecuteReader();
            while (dr.Read())
            {
                this.chart1.Series["Date"].Points.AddXY(dr.GetString(3), dr.GetInt32(6));

            }

        }
        catch(Exception ex)
        {
            MessageBox.Show(ex.Message);
        }

            connection.Close();
         }
         catch (Exception ex)
         {
             MessageBox.Show(ex.Message);
         }
    }