Use the conventional hyperlink tags in the bootstrap dropdown-menu:
<ul class="dropdown-menu">
@foreach (var searchType in new[] { "User", "Restaurant", "Cuisine" })
{
<li><a href="#">@searchType</a></li>
}
</ul>
Then use JQuery to set a hidden input value when these hyperlinks are selected:
<input type="hidden" name="SearchBy" />
<script>
$(".dropdown-menu a").click(function() {
$("input[name='SearchBy']").val($(this).html());
});
</script>