private void btnexit_Click(object sender, EventArgs e)
{
this.Hide();
frmAdmin formnhanvien = new frmAdmin();
formnhanvien.ShowDialog();
}
private void btnlogin_Click(object sender, EventArgs e)
{
if (loginbll.IsAccess(txtusername.Text, txtpassword.Text))
{
this.Hide();
frmAdmin adminpage = new frmAdmin();
adminpage.ShowDialog();
}
}