private void btnDangXuat_Click(object sender, EventArgs e)
        {
            DialogResult dialogResult = MessageBox.Show("Bạn chắc chắn đăng xuất?", "", MessageBoxButtons.YesNo, MessageBoxIcon.Question);

            if (dialogResult == DialogResult.Yes)
            {
                this.Hide();
                frm_login login = new frm_login();
                login.ShowDialog();
                this.Close();
            }
        }
 private void timerShow_Tick(object sender, EventArgs e)
 {
     panelSlide.Left += 2;
     if (panelSlide.Left > 220)
     {
         panelSlide.Left = 0;
     }
     a += 10;
     if (a == 3000)
     {
         frm_login frm_Login = new frm_login();
         frm_Login.ShowDialog();
     }
     if (a == 3000)
     {
         timerShow.Stop();
         this.Close();
     }
 }