radioButton& listBox&numericUpDown 操作

private void numericUpDown1_ValueChanged(object sender, EventArgs e)
{
if (numericUpDown1.Value == 1)
radioButton1.Checked = true;
if (numericUpDown1.Value == 2)
radioButton2.Checked = true;
if (numericUpDown1.Value == 3)
radioButton3.Checked = true;

}

private void radioButton1_CheckedChanged(object sender, EventArgs e)
{
if (radioButton1.Checked)
numericUpDown1.Value = 1;
}

private void radioButton2_CheckedChanged(object sender, EventArgs e)
{
if (radioButton2.Checked)
numericUpDown1.Value = 2;
}

private void radioButton3_CheckedChanged(object sender, EventArgs e)
{
if (radioButton3.Checked)
numericUpDown1.Value = 3;
}

private void checkBox1_CheckedChanged(object sender, EventArgs e)
{
if (checkBox1.Checked)
listBox2.Items.Add("English");
else
listBox2.Items.Remove("English");
}

private void checkBox2_CheckedChanged(object sender, EventArgs e)
{
if (checkBox2.Checked)
listBox2.Items.Add("German");
else
listBox2.Items.Remove("German");

}

private void checkBox3_CheckedChanged(object sender, EventArgs e)
{
if (checkBox3.Checked)
listBox2.Items.Add("French");
else
listBox2.Items.Remove("French");
}