Bind DropDownlists with JQuery in Asp.Net - asp.net

Question

I have 3 dropdownlists for Country,State and Metro.
I want to when user seclect Country then State dropdownlist fill Jquery and when select Sate then Metro dropdownlist fill(like cascading dropdownlist of ajax).These process i want to do with JQuery.

Answer 1

I am going to describe it in ASP.NET MVC, but the same can be achieved if you either write an ASP.NET web service or just put a few page methods in your code behind to do the same - you'll also need a JSON serializer, either a 3rd party solution or the one in WCF.
Using MVC, first, let's have three controller actions - one to display the page, countries will be static, and two to get the states and metros respectively:
public ActionResult Index()
{
ViewData["Countries"] = _countryRepository.GetList();
return View();
}
public ActionResult States(string countryCode)
{
var states = _stateRepository.GetList(countryCode);
return Json(states);
}
public ActionResult Metros(string countryCode, string state)
{
var metros = _metroRepository.GetList(countryCode, state);
return Json(metros);
}
In the view, you have three DropDownLists, one is bound to the ViewData["Countries"] object, say it's named Countries, you can get the states in jQuery with an Ajax call like this:
$('#Countries').change(function() {
var val = $(this).val();
$states = $('#States');
$.ajax({
url: '<%= Url.Action('States') %>',
dataType: 'json',
data: { countryCode: val },
success: function(states) {
$.each(states, function(i, state) {
$states.append('<option value="' + state.Abbr+ '">' + state.Name + '</option>');
});
},
error: function() {
alert('Failed to retrieve states.');
}
});
});
The Metros drop down would be filled analogically, passing both the country and state selection to the server and getting back a JSON object with an array of metro areas.
I left out the details of repository implementation, just fill up the result variable on the server with a collection of states/metro areas in some way. I also made an assumption that the State class would have two properties - Abbr (e.g., 'CA') and Name (e.g., California).
I hope that it helps you in any way, or at least directs you somehow towards the solution.