private void TraCuu_Load(object sender, EventArgs e)
{
SachBUS objSach = new SachBUS();
if (objSach.GetTheloai() != null)
{
cbTheloai.DataSource = objSach.GetTheloai();
cbTheloai.DisplayMember = "theloai";
}
else
{
MessageBox.Show("Lỗi tải dữ liệu");
}
cbTheloai.Text = "";
LoadData();
txtSl.Enabled = false;
txtMa.Enabled = false;
butLuu.Enabled = false;
}