public void LoadMaDoan()
{
DataTable tbMaDoan = doan.getDsMaDoan1();
cbbMaDoan.DataSource = tbMaDoan;
cbbMaDoan.DisplayMember = "MaDoan";
cbbMaDoan.ValueMember = "MaDoan";
}
private void loaddMaDoan()
{
DataTable tbMaDoan = doan.getDsMaDoan1();
DataRow row = tbMaDoan.NewRow();
row[0] = -1;
tbMaDoan.Rows.Add(row);
cbbMaDoan.DataSource = tbMaDoan;
cbbMaDoan.DisplayMember = "MaDoan";
cbbMaDoan.ValueMember = "MaDoan";
cbbMaDoan.Text = "-1";
}