You may try this:
bool isChecked = false;
private void radioButton1_CheckedChanged(object sender, EventArgs e)
{
for (int i = 0; i < routeNamesListView.Items.Count; i++)
{
if (radioButton1.Checked)
routeNamesListView.Items[i].Checked = true;
else
routeNamesListView.Items[i].Checked = false;
}
isChecked = radioButton1.Checked;
}
private void radioButton1_Click(object sender, EventArgs e)
{
if (radioButton1.Checked && !isChecked)
radioButton1.Checked = false;
else
{
radioButton1.Checked = true;
isChecked = false;
}
}