I believe you are looking for a JQuery solution, not server-side code. You may need to add classes to the controls involved, since ASP.NET generates its own ID values for server-side controls. If you add classes, your JQuery code would look like this:
$('.toggle').click(function() {
var disableTextBoxes = ($(this).val() == 2);
$('.target').prop('disabled', disableTextBoxes);
});
If not, you could base it off the type of the controls, but that's a little dangerous:
$('input[type=radio]').click(function() {
var disableTextBoxes = ($(this).val() == 2);
$('input[type=text]').prop('disabled', disableTextBoxes);
});