private void txtTK_TextChanged(object sender, EventArgs e)
{
if (cbTK.Text == "Mã Khách")
{
dgvKhach.DataSource = tk.TKKhach_MaKhach(txtTK.Text);
}
else if (cbTK.Text == "Tên Khách")
{
dgvKhach.DataSource = tk.TKKhach_TenKhach(txtTK.Text);
}
else if (cbTK.Text == "CMND")
{
dgvKhach.DataSource = tk.TKKhach_CMND(txtTK.Text);
}
}