private void resetform() { txtHoTen.Enabled = false; txtVaiTro.Enabled = false; cbSach.Enabled = false; cbTacGia.Enabled = false; btnThemTacGia.Enabled = true; btnHuyTacGia.Enabled = false; btnLuuTacGia.Enabled = false; btnXoaTacGia.Enabled = false; btnThemThamGia.Enabled = true; btnHuyThamGia.Enabled = false; btnLuuThamGia.Enabled = false; btnXoaThamGia.Enabled = false; txtHoTen.Text = ""; txtVaiTro.Text = ""; cbSach.DataSource = client.listAllBook(); cbSach.DisplayMember = "TieuDeSach"; cbSach.ValueMember = "MaSach"; cbTacGia.DataSource = client.listAllAuthor(); cbTacGia.DisplayMember = "HoTen"; cbTacGia.ValueMember = "MaTacGia"; dgvTacGia.DataSource = client.listAllAuthor(); dgvThamGia.DataSource = client.listAllAttend(); }