private void Frm_Diem_Load(object sender, EventArgs e)
{
string sql = "select * from sv";
DataTable dt = new DataTable();
dt = s.Load2(sql);
cboMasv.DataSource = dt;
cboMasv.DisplayMember = "Masv";
cboMasv.ValueMember = "Masv";
string sql1 = "select * from mon";
DataTable dt1 = new DataTable();
dt1 = m.Load2(sql1);
cboMamon.DataSource = dt1;
cboMamon.DisplayMember = "Mamon";
cboMamon.ValueMember = "Mamon";
string sql2 = "select * from diem";
dataGridView1.DataSource = d.Load2(sql2);
}