// Button sửa
private void EditButton_Click(object sender, EventArgs e)
{
AddBt.Hide();
EditButton.Hide();
DeleteButton.Hide();
SaveAddBt.Hide();
CancelAddBt.Hide();
SaveEditButton.Show();
CancelEdit.Show();
textBox6.Enabled = true;
textBox9.Enabled = true;
textBox8.Enabled = true;
textBox7.Enabled = true;
radioButton5.Enabled = true;
radioButton6.Enabled = true;
dateTimePicker4.Enabled = true;
dateTimePicker5.Enabled = true;
dateTimePicker6.Enabled = true;
}
