private void btn_sum_class_Click(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection("Data Source = studio;Initial Catalog=Uni_shomal;Integrated Security = True");
SqlCommand cmd1 = new SqlCommand("select sum(class.cap) from class where st = 8", con);
SqlCommand cmd2 = new SqlCommand("select sum(class.cap) from class where st = 10", con);
con.Open();
dataGridView1_class2.Columns.Add("Zarfiat_8", "ظرفیت_کلاسهای_8صبح");
dataGridView1_class2.Columns.Add("Zarfiat_10", "ظرفیت_کلاسهای_10صبح");
dataGridView1_class2.Rows.Add(cmd1.ExecuteScalar() , cmd2.ExecuteScalar());
con.Close();
con.Dispose();
cmd1.Dispose();
cmd2.Dispose();
}