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Cascading (Dependent) Country State City DropDownLists using jQuery AJAX in ASP.Net MVC

I need to populate Cascading Country, State and City DropDownLists using jQuery AJAX in ASP.Net MVC.
This is the tutorial
https://www.aspsnippets.com/Articles/Cascading-Dependent-Country-State-City-DropDownLists-using-jQuery-AJAX-in-ASPNet-MVC.aspx
And working correctly.
My problem is validate these DropDownList when send the form
#Html.DropDownListFor(m => m.CountryId, Model.Countries, "[ === Select CountryId === ]", new { #Class = "textarea" })
#Html.ValidationMessageFor(m => m.CountryId, "", new { #class = "text-danger" })
#Html.DropDownListFor(m => m.StateId, Model.States, "[ === Select StateId === ]", new { #Class = "textarea" })
#Html.ValidationMessageFor(m => m.StateId, "", new { #class = "text-danger" })
In this moment if on the DropDownList no value is selected the form is validate.
How to do resolve this?
My View javascript part follow
#section Scripts {
<script src="https://code.jquery.com/jquery-1.10.2.js"
integrity="sha256-it5nQKHTz+34HijZJQkpNBIHsjpV8b6QzMJs9tmOBSo="
crossorigin="anonymous"></script>
<script type="text/javascript">
$(function () {
$("select").each(function () {
if ($(this).find("option").length <= 1) {
$(this).attr("disabled", "disabled");
}
});
$("select").change(function () {
var value = 0;
if ($(this).val() != "") {
value = $(this).val();
}
var id = $(this).attr("id");
$.ajax({
type: "POST",
url: "/Home/AjaxMethod",
data: '{type: "' + id + '", value: "' + value + '"}',
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (response) {
var dropDownId;
var list;
switch (id) {
case "CountryId":
list = response.States;
DisableDropDown("#StateId");
DisableDropDown("#CityId");
PopulateDropDown("#StateId", list);
break;
case "StateId":
dropDownId = "#CityId";
list = response.Cities;
DisableDropDown("#CityId");
PopulateDropDown("#CityId", list);
break;
}
},
failure: function (response) {
alert(response.responseText);
},
error: function (response) {
alert(response.responseText);
}
});
});
});
function DisableDropDown(dropDownId) {
$(dropDownId).attr("disabled", "disabled");
$(dropDownId).empty().append('<option>[ === Select CountryId === ]</option>');
}
function PopulateDropDown(dropDownId, list) {
if (list != null && list.length > 0) {
$(dropDownId).removeAttr("disabled");
$.each(list, function () {
$(dropDownId).append($("<option></option>").val(this['Value']).html(this['Text']));
});
}
}
</script>
}

Why not implement something like this:
if ($(this).val() == "") {
// return validation message
return;
}
else
{
value = $(this).val();
}

It is possible to refresh ViewBag value in the view?

I'm trying to do a dynamic dropdownlist :
I get the options of the dropdownlist from a database and put them in an objects list. In accordance with a checkbox value i remove objects from the list and set this list as a ViewBag value.
public ActionResult ThematicManagement(string Id, string IsAdult, string flagAdult)
{
.....
ViewBag.DDL = null;
var response = VodCatalogBUS.GetParentThematics();
List<oboThematic> list = new List<oboThematic>();
list = response.Data;
if (IsAdult == null || IsAdult == "false")
list.RemoveAll(x => x.IsAdult == true && x.Id != 1007);
else
list.RemoveAll(x => x.IsAdult == false && x.Id != 1007);
ViewBag.DDL = new SelectList(list, "Id", "Name");
....
Then in my view i fill the dropdownlist like that :
#Html.DropDownList("ParentThematic", (SelectList)ViewBag.DDL, new { #class="dropdown" })
<label><input type="checkbox" value="" id="ChkIsAdult" name="ChkIsAdult">Adulte</label>
There is no problems here, i obtain the dropdown list with 4 options after the RemoveAll in the controller. Then if i click the checkbox, i must obtain 3 other options.
So I use an ajax call to return into the controller in the aim to update Viewbag's value :
$('#ChkIsAdult').change(function () {
var IsAdult = $('#ChkIsAdult').is(':checked');
var url = dev + "/Legacy/ThematicManagement";
$.ajax({
url: url,
cache: false,
type: 'POST',
data: {
IsAdult: IsAdult,
flagAdult : 'true',
},
success: function () {
alert('test');
}
});
})
It works i return into the controller, but i think that the view isn't refresh so i retreive the old values (the 4 options) of the dropdownlist after clicking the checkbox.
I also try with ViewData and TempData to replace ViewBag but i've always the same proprem !
According to you, it is the good solution ? Can it works ?

Here is the response :
Controller
var response = VodCatalogBUS.GetParentThematics();
List<oboThematic> list = new List<oboThematic>();
list = response.Data;
list.RemoveAll(x => x.IsAdult == true && x.Id != 1007);
var responseAdult = VodCatalogBUS.GetParentThematics();
List<oboThematic> listAdult = new List<oboThematic>();
listAdult = responseAdult.Data;
listAdult.RemoveAll(y => y.IsAdult == false && y.Id != 1007);
ViewBag.DDL = new SelectList(list, "Id", "Name");
ViewBag.DDLAdult = new SelectList(listAdult, "Id", "Name");
View :
#Html.DropDownList("ParentThematic", (SelectList)ViewBag.DDL, new { #class="dropdown" })
#Html.DropDownList("ParentThematicAdult", (SelectList)ViewBag.DDLAdult, new { #class="dropdown" , #style="display:none"})
JS :
$('#ChkIsAdult').change(function () {
if ($('#ChkIsAdult').is(':checked')) {
$('#ParentThematic').hide();
$('#ParentThematicAdult').show();
var value = $('#ParentThematicAdult').val();
var IsAdult = $('#ChkIsAdult').is(':checked');
var url = dev + "/Legacy/ThematicManagement";
$.ajax({
url: url,
cache: false,
type: 'POST',
data: {
Id: value,
IsAdult: IsAdult
},
success: function (data) {
$('#result').empty().append($(data).find('table'))
}
});
}
else
{
$('#ParentThematic').show();
$('#ParentThematicAdult').hide();
var value = $('#ParentThematic').val();
var IsAdult = $('#ChkIsAdult').is(':checked');
var url = dev + "/Legacy/ThematicManagement";
$.ajax({
url: url,
cache: false,
type: 'POST',
data: {
Id: value,
IsAdult: IsAdult
},
success: function (data) {
$('#result').empty().append($(data).find('table'))
}
});
}
})

Can't Filling DropDownList with Ajax in MVC

Everything seems OK but value shows empty..
I have 2 dropdownlist, when I choose first one, I got the index and used ajax to fill other dropdownlist.. But problem is that I dont have result.. loop that is in ajax, doesnt work.. and I checked web tool of firefox, result seems empty, but in C# code, the list has items..
so here is my ajax
$.ajax({
url: "#Url.Action("ElectionList", "Home")",
type: "GET",
dataType: "json",
data: { electionTypeId: selectedId },
success: function (data) {
if (data != null) {
//HERE IS WORKING
alert("OK");
electionCombo.html('');
$.each(data, function (index,item) {
//here is not working !!!
alert("hobaaa: " + index);
alert("data: " + item.Text);
// alert(option.ID + " " + option.politicName);
// electionCombo.append($('<option></option>').val(option.Value).html(option.Text));
});
}
here is my c# code
[AcceptVerbs(HttpVerbs.Get)]
public JsonResult ElectionList(int electionTypeId)
{
var service = new EvoteServicesProviderClient();
try
{
var electtionType = service.getAllElectionTypes().FirstOrDefault(e => e.ID == electionTypeId);
var res =
service.searchElectionByType(electtionType.electionTypeName)
.ToList()
.Where(e => e.startDate >= DateTime.Now)
.Select(e => new SelectListItem
{
Value = e.ID.ToString(),
Text = e.politicName
});
var list = new SelectList(res, "Value", "Text");
return Json(list, JsonRequestBehavior.AllowGet);
// return Json(new { success = true, result = list },
// JsonRequestBehavior.AllowGet);
}
catch{}
return Json(new { success = false, message = "An error occured" }, JsonRequestBehavior.AllowGet);
}
this is the html side
#using (Html.BeginForm("ElectionList", "Home", FormMethod.Post, new {#class = "form-horizontal", id = "electionlistform"}))
{
#Html.LabelFor(m => m.SelectedElectionId, new {#class = "col-md-2 control-label"})
#Html.DropDownListFor(m => m.SelectedElectionId, Model.ElectionList, new {#class = "form-control", id = "electionList"})
#Html.ValidationMessageFor(m => m.SelectedElectionId)
}
As I wrote, the list is not empty (in actionresult ElectionList)
What I am missing?

Try this :
$.each(data, function () {
//here is not working !!!
alert("hobaaa: " + this.Value);
alert("data: " + this.Text);
});
You can access the property directly because it's json.
UPDATE
Just return the list server side :
var res =
service.searchElectionByType(electtionType.electionTypeName)
.ToList()
.Where(e => e.startDate >= DateTime.Now)
.Select(e => new SelectListItem
{
Value = e.ID.ToString(),
Text = e.politicName
});
return Json(res, JsonRequestBehavior.AllowGet);

What I do when I need to fill a dropdown is the same as you, but I'm using a for loop instead of each (maybe it's the same but for me it's working). And by the way, in your ajax code sample you are not closing the ajax function. Hope in your real code it's okay.
$.ajax({
url: "#Url.Action("ElectionList", "Home")",
type: "GET",
dataType: "json",
data: { electionTypeId: selectedId },
success: function (data) {
if (data != null) {
//HERE IS WORKING
alert("OK");
electionCombo.html('');
for (i in data) {
var result = data[i];
// electionCombo.append($('<option></option>').val(result.Value).html(result.Text));
}
}
});
By the way, if it's still not working , you could try a ViewModel with the options you need
public class ViewModelExample
{
public Int32 ValueOption { get; set; }
public String TextOption { get; set; }
}
And use it in your list instead of selectlist. With viewmodels I don't have problems getting the values with json.

Selected values in cascading dropdownlists reset on post

I have MVC4 web-application with 2 cascading dropdownlists (parent and child) and button with post action for filtering data dislpayed in grid depending on selected values in dropdownlists. Cascading dropdownlists I realized with Microsoft AJAX (Ajax.BeginForm helper), almost as described here: http://weblogs.asp.net/raduenuca/archive/2011/03/20/asp-net-mvc-cascading-dropdown-lists-tutorial-part-3-cascading-using-microsoft-ajax-ajax-beginform-helper.aspx. BTW, dropdownlists are located in partial view.
The problem is that when I click button, postback is performed and selected values in cascading dropdownlists are reset to original values, i.e. "Please, select value".
Does anybody know how to solve this problem?
Thanks in advance for all who give an answers!
Here is my code with partial view with cascading dropdownlists:
<script type="text/javascript">
$(function () {
$('#Sections').change(function () {
var sectionId = $("#Sections :selected").val();
if (sectionId != "") {
$.ajax({
type: "GET",
contentType: "application/json; charset=utf-8",
url: '#Url.Action("GetDocumentTypesList", "DocumentTypes")',
data: { "id": sectionId },
dataType: "json",
success: function (data) {
var items = "";
$.each(data, function (i, documentType) {
items += "<option value='" + documentType.Value + "'>" + documentType.Text + "</option>";
});
$('#Types').html(items);
},
error: function (result) {
alert('Service call failed: ' + result.status + ' Type :' + result.statusText);
}
});
}
else {
var items = '<option value="">Select</option>';
$('#Types').html(items);
}
});
});
#Html.DropDownList("Sections", new SelectList(ViewBag.Sections, "Id", "Name"), "Please select parent type", new { id = "Sections" })
#Html.DropDownList("Types", new SelectList(ViewBag.Types, "Id", "Name"), "Please select child type", new { id = "Types" })
And here is controller code for partial view:
public class DocumentTypesController : Controller
{
static List<DocumentType> documentTypes = DocumentsDAL.GetDocumentTypes(true, true, false);
// GET: /DocumentTypes/
public ActionResult Index()
{
var root = documentTypes.Where(d => d.ParentId == null).ToList();
ViewBag.Sections = root;
ViewBag.Types = new List<DocumentType> { new DocumentType { Id = -1, Name = "Select" } };
return PartialView("~/Views/Shared/_DocumentTypes.cshtml", root);
}
// Get values for parent dropdownlist.
[AcceptVerbs(HttpVerbs.Get)]
public JsonResult GetDocumentTypesList(string id)
{
var items = GetDocumentTypes(Convert.ToInt32(id)).Select(a => new SelectListItem
{
Text = a.Name,
Value = a.Id.ToString(CultureInfo.InvariantCulture)
});
return Json(items, JsonRequestBehavior.AllowGet);
}
// Get values for child dropdownlist.
[AcceptVerbs(HttpVerbs.Get)]
public JsonResult GetDocumentTypeData(string sectionId, string typeId)
{
var documentTypeData = GetDocumentTypes(Convert.ToInt32(sectionId))
.First(d => d.Id == Convert.ToInt32(typeId));
return Json(documentTypeData, JsonRequestBehavior.AllowGet);
}
private static IEnumerable<DocumentType> GetDocumentTypes(int id)
{
return documentTypes.First(d => d.Id == id).DocumentTypes;
}
}
And this is a base view where it's used partial one:
#using (Ajax.BeginForm("Index", null, new AjaxOptions
{
InsertionMode = InsertionMode.Replace,
UpdateTargetId = "documentsGrid"
}, new { #class = "form-inline" }))
{
<div>
#{ Html.RenderAction("Index", "DocumentTypes", new { area = "" }); }
</div>
<p class="form-inline">
#Html.LabelForModel(#Resources.LabelPeriodFrom)
#Html.Raw(" ")
#Html.TextBox("periodFrom", "", new { #class = "input-small" })
#Html.Raw(" ")
#Html.LabelForModel(#Resources.LabelPeriodTo)
#Html.Raw(" ")
#Html.TextBox("periodTo", "", new { #class = "input-small" })
#Html.Raw(" ")
<input type="submit" class="btn" value="Filter" />
</p>
}
And controller for basic view with post-action Index, which fired when user press button:
public class IssuerDocumentsController : Controller
{
static readonly IEnumerable<IssuerDocument> Documents = DocumentsDAL.GetDocuments(1, 1).AsEnumerable();
[HttpPost]
public ActionResult Index(FormCollection collection)
{
var documents = Documents.AsEnumerable();
// Check if document section filter is applied.
if (!string.IsNullOrEmpty(collection.Get("Sections")))
{
var documentSectionId = Convert.ToInt32(collection.Get("Sections"));
documents = documents.Where(d => d.SectionId == documentSectionId);
}
// Check if document type filter is applied.
if (!string.IsNullOrEmpty(collection.Get("Types")))
{
var documentTypeId = Convert.ToInt32(collection.Get("Types"));
documents = documents.Where(d => d.TypeId == documentTypeId);
}
return View(documents);
}
}

on select change event - Html.DropDownListFor

I have two dropdownlist. The selected value from the first one loads the other. How do I do that when I have the helper methods in a controller?
#using (Html.BeginForm())
{
<div>
<table width="100%" cellpadding="0" cellspacing="0">
<tr>
<td><b>Select a District:</b></td>
<td>#Html.DropDownListFor(m => m.DistrictId, ViewData["DMManagers"] as IEnumerable<SelectListItem>, "Select One")</td>
</tr>
<tr>
<td><b>Select a TM:</b></td>
<td>#Html.DropDownListFor(m => m.TMId, ViewData["TMManagers"] as IEnumerable<SelectListItem>, "Select One")</td>
</tr>
</table>
</div>
}
private void LoadDistrictManagers()
{
var _DMS = (from c in SessionHandler.CurrentContext.ChannelGroups
join cgt in SessionHandler.CurrentContext.ChannelGroupTypes on c.ChannelGroupTypeId equals cgt.ChannelGroupTypeId
where cgt.Name == "District Manager"
select new { c.ChannelGroupId, c.Name }).OrderBy(m => m.Name);
ViewData["DMManagers"] = new SelectList(_DMS, "ChannelGroupId", "Name");
}
private void LoadTerritoryManagers(int districtId)
{
var _TMS = (from c in SessionHandler.CurrentContext.ChannelGroups
join cgt in SessionHandler.CurrentContext.ChannelGroupTypes on c.ChannelGroupTypeId equals cgt.ChannelGroupTypeId
where cgt.Name == "Territory" && c.ParentChannelGroupId == districtId
select new { c.ChannelGroupId, c.Name }).OrderBy(m => m.Name);
ViewData["TMManagers"] = new SelectList(_TMS, "ChannelGroupId", "Name");
}
public ActionResult SummaryReport()
{
DistrictManagerModel model = new DistrictManagerModel();
LoadDistrictManagers();
return View("AreaManager", model);
}

Give both dropdowns unique IDs using the HTTPAttributes field:
#Html.DropDownListFor(m => m.DistrictId, ViewData["DMManagers"] as IEnumerable<SelectListItem>, "Select One", new {#id="ddlDMManagers"})
2nd dropdown should be initialized as an empty list:
#Html.DropDownListFor(m => m.TMId, Enumerable.Empty<SelectListItem>(), new {#id="ddlTMManagers"})
If you don't mind using jQuery ajax to update the 2nd dropdown when a 'change' event is triggered on the 1st dropdown:
$(function() {
$('select#ddlDMManagers').change(function() {
var districtId = $(this).val();
$.ajax({
url: 'LoadTerritoryManagers',
type: 'POST',
data: JSON.stringify({ districtId: districtId }),
dataType: 'json',
contentType: 'application/json',
success: function (data) {
$.each(data, function (key, TMManagers) {
$('select#ddlTMManagers').append('<option value="0">Select One</option>');
// loop through the TM Managers and fill the dropdown
$.each(TMManagers, function(index, manager) {
$('select#ddlTMManagers').append(
'<option value="' + manager.Id + '">'
+ manager.Name +
'</option>');
});
});
}
});
});
});
Add this class to your controller namespace:
public class TMManager
{
public int Id {get; set;}
public string Name {get; set;}
}
You will need to update your controller action, LoadTerritoryManagers(), to respond to the ajax request and return a JSON array of {Id,Name} objects.
[HttpPost]
public ActionResult LoadTerritoryManagers(int districtId)
{
var _TMS = (from c in SessionHandler.CurrentContext.ChannelGroups
join cgt in SessionHandler.CurrentContext.ChannelGroupTypes on c.ChannelGroupTypeId equals cgt.ChannelGroupTypeId
where cgt.Name == "Territory" && c.ParentChannelGroupId == districtId
select new TMManager(){ Id = c.ChannelGroupId, Name = c.Name }).OrderBy(m => m.Name);
if (_TMS == null)
return Json(null);
List<TMManager> managers = (List<TMManager>)_TMS.ToList();
return Json(managers);
}

Use the following code. It is used in my project. For Zone and Region I used two drop-down list. On change Zone data I loaded the Region drop-down.
In View page
#Html.DropDownList("ddlZone", new SelectList(#ViewBag.Zone, "Zone_Code", "Zone_Name"), "--Select--", new { #class = "LoginDropDown" })
#Html.DropDownList("ddlRegion", Enumerable.Empty<SelectListItem>(), new { #class = "LoginDropDown" })
The Zone need to load when the view page is load.
In the controller write this method for Region Load
[WebMethod]
public JsonResult LoadRegion(string zoneCode)
{
ArrayList arl = new ArrayList();
RASolarERPData objDal = new RASolarERPData();
List<tbl_Region> region = new List<tbl_Region>();
region = erpDal.RegionByZoneCode(zoneCode);
foreach (tbl_Region rg in region)
{
arl.Add(new { Value = rg.Reg_Code.ToString(), Display = rg.Reg_Name });
}
return new JsonResult { Data = arl };
}
Then use the following JavaScript
<script type="text/javascript">
$(document).ready(function () {
$('#ddlZone').change(function () {
LoadRegion(this.value);
});
function LoadRegion(zoneCode) {
$.ajax({
type: "POST",
url: '#Url.Action("LoadRegion", "RSFSecurity")',
data: "{'zoneCode':'" + zoneCode + "'}",
contentType: "application/json; charset=utf-8",
dataType: 'json',
cache: false,
success: function (data) {
$('#ddlRegion').get(0).options.length = 0;
$('#ddlRegion').get(0).options[0] = new Option("--Select--", "0");
$.map(data, function (item) {
$('#ddlRegion').get(0).options[$('#ddlRegion').get(0).options.length] = new Option(item.Display, item.Value);
});
},
error: function () {
alert("Failed to load Item");
}
});
}
});
</script>

We can use the jquery to get and fill the dropdown like this:
<script>
function FillCity() {
var stateId = $('#State').val();
$.ajax({
url: '/Employees/FillCity',
type: "GET",
dataType: "JSON",
data: { State: stateId},
success: function (cities) {
$("#City").html(""); // clear before appending new list
$.each(cities, function (i, city) {
$("#City").append(
$('<option></option>').val(city.CityId).html(city.CityName));
});
}
});
}
</script>
For more detail see
MVC DropDownListFor fill on selection change of another dropdown