You could use a normal link with target="_blank" attribute:
@Html.ActionLink(
"Generate PDF",
"GeneratePdf",
"MyController",
null,
new {
url = "some url",
target = "_blank"
}
)
or if you want a button you could use javascript in separate JS file you can use Jquery:
$(function() {
$('#btnID').click(function() {
var url = $(this).data('data');
window.open(url, 'data');
return false;
});
});