Develop Reference

Using PagedList for paginating product list

I am trying to show a list of products and show pagination. So, I decided to use PagedList plugin. I read some examples of how to modify controller and view to do so in the link below.
https://github.com/TroyGoode/PagedList
But, instead of using ViewBag, I managed to send a group of products to controller by doing some modifications to controller:
public ActionResult Index(string name)
{
IEnumerable<ProductModel> productList = new HashSet<ProductModel>();
if (string.IsNullOrWhiteSpace(name))
{
}
else
{
CategoryModel category = db.Categories.Where(x => x.CategorytUrl == name).FirstOrDefault();
if (category != null)
{
int catId = category.Id;
string catName = category.Name;
ViewBag.categoryName = category.Name;
List<SpecItemsModel> options = Products.GetFilter(category.Id);
//initialize the list
//productList = Products.ProductLists(catId);
ViewBag.filters = options;
var childrenIDs = db.Categories.Where(x => x.ParentId == category.Id).Select(x => x.Id);
var grandchildrenIDs = db.Categories.Where(x => childrenIDs.Contains((int)x.ParentId)).Select(x => x.Id);
List<int> catIds = new List<int>();
catIds.Add(category.Id);
catIds.AddRange(childrenIDs);
catIds.AddRange(grandchildrenIDs);
var templates = db.ProductTemplates.Where(t => catIds.Contains(t.CategoryId)).Select(x => x.Id);
productList = db.Products.Where(p => templates.Contains(p.ProductTemplateId));
}
}
var pageNumber = page ?? 1;
//var onePageOfProducts = productList.OrderBy(i => i.AdminRate).ToPagedList(pageNumber, 2);
//ViewBag.OnePageOfProducts = onePageOfProducts;
return View(productList.OrderBy(i => i.AdminRate).ToPagedList(pageNumber, 2));
}
As the result, products are showing up in he view in 2-product groups. the only thing I don't know is how to modify html pager of the example I mentioned to show paging controls. :
#model IEnumerable<fardashahr.Models.ProductModel>
<div class="col-md-9">
#foreach (var item in Model)
{
<a href="#Url.Action("Details","Home",new { name = item.ProductUrl })">
<img class="bd-placeholder-img card-img-top mw-100" src="/Images/Uploads/Products/#item.Id/Thumbs/#item.ImageName" />
</a>
<p class="card-text">
<h3>
#item.ShortName
</h3>
</p>
}
</div>
</div>
Any suggestions?

Sorry, I didn't check the github project you posted.
In Controller
Change
public ActionResult Index(string name)
to
public ActionResult Index(int page, string name)
In View
Use
#Html.PagedListPager( (IPagedList)Model, page => Url.Action("Index", new { page = page, name = "***" }) )
to show page navigator.

Server side paging & sorting and filtering Performance

I have only one table in database with 2 million records , i want the user to be able to browse the data and also have the ability to sort data and filter it.
also user should be able to navigate between pages
Here is my MVC controller
public class AssetController : Controller
{
private ApplicationDbContext _dbContext;
public ApplicationDbContext DbContext
{
get
{
return _dbContext ?? HttpContext.GetOwinContext().Get<ApplicationDbContext>();
}
private set
{
_dbContext = value;
}
}
public AssetController()
{
}
public AssetController(ApplicationDbContext dbContext)
{
_dbContext = dbContext;
}
// GET: Asset
public ActionResult Index()
{
return View();
}
public ActionResult Get([ModelBinder(typeof(DataTablesBinder))] IDataTablesRequest requestModel)
{
IEnumerable<Asset> query = DbContext.Assets;
var totalCount = query.Count();
#region Filtering
// Apply filters for searching
if (requestModel.Search.Value != string.Empty)
{
var value = requestModel.Search.Value.Trim();
query = query.Where(p => p.Barcode.Contains(value) ||
p.Manufacturer.Contains(value) ||
p.ModelNumber.Contains(value) ||
p.Building.Contains(value)
);
}
var filteredCount = query.Count();
#endregion Filtering
#region Sorting
// Sorting
var sortedColumns = requestModel.Columns.GetSortedColumns();
var orderByString = String.Empty;
foreach (var column in sortedColumns)
{
orderByString += orderByString != String.Empty ? "," : "";
orderByString += (column.Data) + (column.SortDirection == Column.OrderDirection.Ascendant ? " asc" : " desc");
}
query = query.OrderBy(orderByString == string.Empty ? "BarCode asc" : orderByString);
#endregion Sorting
// Paging
query = query.Skip(requestModel.Start).Take(requestModel.Length);
var data = query.Select(asset => new
{
AssetID = asset.AssetID,
BarCode = asset.Barcode,
Manufacturer = asset.Manufacturer,
ModelNumber = asset.ModelNumber,
Building = asset.Building,
RoomNo = asset.RoomNo,
Quantity = asset.Quantity
}).ToList();
return Json(new DataTablesResponse(requestModel.Draw, data, filteredCount, totalCount), JsonRequestBehavior.AllowGet);
}
}
and below is index.cshtml
<div class="row">
<div class="col-md-12">
<div class="panel panel-primary list-panel" id="list-panel">
<div class="panel-heading list-panel-heading">
<h1 class="panel-title list-panel-title">Properties</h1>
</div>
<div class="panel-body">
<table id="datatable" class="table table-striped table-bordered" style="width:100%;">
<thead>
<tr>
<th>BarCode</th>
<th>Manufacturer</th>
<th>Building</th>
<th>Quantity</th>
</tr>
</thead>
</table>
</div>
</div>
</div>
</div>
#section Scripts
{
<script type="text/javascript">
$(document).ready(function () {
var datatableInstance = $('#datatable').DataTable({
serverSide: true,
processing: true,
"ajax": {
"url": "#Url.Action("Get","Asset")"
},
lengthMenu: [[10, 25, 50, 100], [10, 25, 50, 100]],
columns: [
{ 'data': 'BarCode' },
{ 'data': 'Manufacturer' },
{
'data': 'Building',
'searchable': true,
},
{
'data': 'Quantity',
'searchable': true,
'render': function (Quantity) {
return "$ " + Quantity;
}
},
],
});
});
</script>
}
I used JQuery data-tables , code is working fine if i have small number of rows - less than 100000 , but if i have large number of rows , it becomes very bad
It takes too long in the following line
var filteredCount = query.Count();
How can i enhance the performance

In my opinion, instead doing "var totalCount = query.Count();" try to make an sql statement with a count over the table, probably you will get a better perfomance.
var totalCount = _context.SqlQuery("Select count(0) from yourTable").FirstOrDefault();
I haven´t tested the perfomance with Count(), but with Distinc() the difference is remarkable.
Hope it helps

How to send selected radiobutton value together with html.actionlink in MVC 5

I did sorting by initial letters in my MVC 5 application. Now I would like to add radio buttons to determine whether it will sort by name or last name.The problem is that I do not know how to send value of a selected radiobutton together with Html.ActionLink (after the user clicks on it) to controller.
I hope it is understandable what I want to achieve.
View:
using (Html.BeginForm())
{
#Html.RadioButton("sortButton", "FirstName", true) <span>First Name</span>
#Html.RadioButton("sortButton", "LastName") <span>Last Name</span>
<div class="form-inline">
<div class="form-group">
<div class="form-horizontal">
#Html.ActionLink("ALL", "Index", new { sortLetter = "" }) |
#Html.ActionLink("A", "Index", new { sortLetter = "A" }) -
#Html.ActionLink("B", "Index", new { sortLetter = "B" }) -
#Html.ActionLink("C", "Index", new { sortLetter = "C" }) -
#Html.ActionLink("D", "Index", new { sortLetter = "D" }) -
etc...
</div>
</div>
</div>
}
Controller:
public class HomeController : Controller
{
private UsersContext ctx = new UsersContext();
public ActionResult Index(string sortLetter, string sortButton)
{
var contacts = from s in ctx.Users
select s;
// Sorting A - Z
if (sortLetter != null)
{
if (sortButton == "FirstName"
{
contacts = contacts.Where(o => o.FirstName.ToUpper().StartsWith(sortLetter));
}
else
{
contacts = contacts.Where(o => o.LastName.ToUpper().StartsWith(sortLetter));
}
}
return View(contacts.ToList());
}
}

You might need to go with workaround using jquery for this
$(function () {
$('.form-horizontal a').on('click', function () {
var url = $(this).attr('href'),
selectedSortLetter = $('input[type="radio"][name="sortButton"]:checked').val();
$(this).attr('href', url + '?sortLetter=' + selectedSortLetter);
//or directly browse to url like below.
location.href = url + '?sortLetter=' + selectedSortLetter;
});
})

better way to load 2 dropdown in mvc

This is how i am loading on page load state and city dropdown:
My Controller method:
This is the first method which is calling when page is loaded.
public ActionResult Index()
{
var states = GetStates();
var cities = Enumerable.Empty<SelectListItem>();
ViewBag.States = states;
ViewBag.Cities = cities;
}
private IEnumerable<SelectListItem> GetStates()
{
using (var db = new DataEntities())
{
return db.States.Select(d => new SelectListItem { Text = d.StateName, Value =d.Id.ToString() });
}
}
[HttpGet]
public ActionResult GetCities(int id)
{
using (var db = new DataEntities())
{
var data = db.Cities.Where(d=>d.StateId==id).Select(d => new { Text = d.CityName, Value = d.Id }).ToList();
return Json(data, JsonRequestBehavior.AllowGet);
}
}
My View:
IEnumerable<SelectListItem> States = ViewBag.States;
IEnumerable<SelectListItem> Cities = ViewBag.Cities;
#Html.DropDownList("State", States, "Select State", new { onchange="loadCities(this)"})
#Html.DropDownListFor(m => m.CityId, Cities, "Select City", new { id="ddlCity"})
function loadCities(obj) {
$.ajax({
url: "/Home/GetCities",
data: { id: $(obj).val() },
contentType:"application/json",
success:function(responce){
var html = '<option value="0">Select City</option>';
$(responce).each(function () {
html += '<option value="'+this.Value+'">'+this.Text+'</option>'
});
$("#ddlCity").html(html);
}
});
}
Any better way then this to load state and city dropdown?
public class HomeController : Controller
{
public ActionResult Index(int id=0)
{
Person model = null;
var states = GetStates().ToList();
var cities = Enumerable.Empty<SelectListItem>();
if (id > 0)
{
using (var db = new DataEntities())
{
model = db.People.Include("City").FirstOrDefault(d => d.Id == id);
if (model == null)
model = new Person();
else
{
states.First(d => d.Value == model.City.StateId.ToString()).Selected = true;
cities = db.Cities.Where(d => d.StateId == model.City.StateId).ToList().Select(d => new SelectListItem { Text = d.CityName,Value=d.Id.ToString(),Selected=d.Id==model.CityId });
}
}
}
else
{
model = new Person();
}
ViewBag.States = states;
ViewBag.Cities = cities;
ViewBag.Persons = GetPersons();
return View(model);
}
[HttpGet]
public ActionResult GetCities(int id)
{
using (var db = new DataEntities())
{
var data = db.Cities.Where(d=>d.StateId==id).Select(d => new { Text = d.CityName, Value = d.Id }).ToList();
return Json(data, JsonRequestBehavior.AllowGet);
}
}
public ActionResult SavePersonDetail([Bind(Exclude = "Id")] Person model)
{
// var employeeDal= new Emploee();
//employee.firstname=model.
if (ModelState.IsValid)
{
var Id = model.Id;
int.TryParse(Request["Id"], out Id);
using (var db = new DataEntities())
{
if (Id > 0)
{
var person = db.People.FirstOrDefault(d => d.Id == Id);
if (person != null)
{
model.Id = Id;
db.People.ApplyCurrentValues(model);
}
}
else
{
db.People.AddObject(model);
}
db.SaveChanges();
}
}
if (!Request.IsAjaxRequest())
{
ViewBag.States = GetStates();
ViewBag.Persons = GetPersons();
ViewBag.Cities = Enumerable.Empty<SelectListItem>();
return View("Index");
}
else
{
return PartialView("_personDetail",GetPersons());
}
}
public ActionResult Delete(int id)
{
using (var db = new DataEntities())
{
var model = db.People.FirstOrDefault(d => d.Id == id);
if (model != null)
{
db.People.DeleteObject(model);
db.SaveChanges();
}
}
if (Request.IsAjaxRequest())
{
return Content(id.ToString());
}
else
{
ViewBag.States = GetStates();
ViewBag.Persons = GetPersons();
ViewBag.Cities = Enumerable.Empty<SelectListItem>();
return View("Index");
}
}
private IEnumerable<SelectListItem> GetStates()
{
using (var db = new DataEntities())
{
return db.States.ToList().Select(d => new SelectListItem { Text = d.StateName, Value =d.Id.ToString() });
}
}
private IEnumerable<Person> GetPersons()
{
using (var db = new DataEntities())
{
return db.People.Include("City").Include("City.State").ToList();
}
}
public ActionResult HomeAjax()
{
ViewBag.States = GetStates();
ViewBag.Cities = Enumerable.Empty<SelectListItem>();
using (var db = new DataEntities())
{
var data = db.States.Include("Cities").Select(d => new { Id = d.Id, Name = d.StateName, Cities = d.Cities.Select(x => new { Id=x.Id,Name=x.CityName}) }).ToList();
ViewBag.CityStateJson = new System.Web.Script.Serialization.JavaScriptSerializer().Serialize(data);
}
ViewBag.Persons = GetPersons();
return View();
}
}
#model IEnumerable<Person>
<div>
<table>
<tr>
<th>
First Name
</th>
<th>
Last Name
</th>
<th>
Email
</th>
<th>
City
</th>
<th>
State
</th>
<th>
Edit
</th>
</tr>
#if (Model.Count() == 0)
{
<tr>
<td colspan="6">
<h3>No data available</h3>
</td>
</tr>
}
else {
foreach (var item in Model) {
<tr data-id="#item.Id">
<td data-id="fn">#item.FirstName</td>
<td data-id="ln">#item.LastName</td>
<td data-id="email">#item.Email</td>
<td data-id="cn">#item.CityName<input type="hidden" value="#item.CityId" /></td>
<td>#item.StateName</td>
<td>
#if (ViewBag.Title == "Home Ajax" || Request.IsAjaxRequest())
{
Update
<span>#Ajax.ActionLink("Delete", "Delete", new { id = item.Id }, new AjaxOptions {OnSuccess="deleteSuccess",OnBegin="showLoader",OnComplete="hideLoader" })</span>
}
else {
<span>#Html.ActionLink("Update", "Index", new { id = item.Id })</span>
<span>#Html.ActionLink("Delete", "Delete", new { id = item.Id })</span>
}
</td>
</tr>
}
}
</table>
</div>
#model Person
#{
ViewBag.Title = "Home Ajax";
IEnumerable<Person> persons = ViewBag.Persons;
IEnumerable<SelectListItem> States = ViewBag.States;
IEnumerable<SelectListItem> Cities = ViewBag.Cities;
IEnumerable<State> fullStates=ViewBag.CityStates;
}
#section featured {
<section class="featured">
<div class="content-wrapper">
<hgroup class="title">
<h1>#ViewBag.Title.</h1>
</hgroup>
</div>
</section>
}
#section styles{
<style type="text/css">
td,th {
border:1px solid;
padding:5px 10px;
}
select {
padding:5px 2px;
width:310px;
font-size:16px;
}
</style>
}
#section scripts{
#Scripts.Render("~/bundles/jqueryval")
<script type="text/javascript">
var jsonArray = #Html.Raw(ViewBag.CityStateJson)
function clearValues() {
$("input[type='text'],select").val('');
$("input[type='hidden'][name='Id']").val(0);
}
function loadCities(obj) {
for (var i = 0; i < jsonArray.length; i++) {
if (jsonArray[i].Id == parseInt($(obj).val())) {
fillCity(jsonArray[i].Cities);
break;
}
}
}
function Edit(obj, Id) {
// alert("hi")
$("input[type='hidden'][name='Id']").val(Id);
var tr = $(obj).closest("tr");
$("#txtfirstName").val($("td[data-id='fn']", tr).text().trim());
$("#txtlastName").val($("td[data-id='ln']", tr).text().trim());
$("#txtemail").val($("td[data-id='email']", tr).text().trim());
var city = $("td[data-id='cn'] input[type='hidden']", tr).val();
var state;
for (var i = 0; i < jsonArray.length; i++) {
for (var j = 0; j < jsonArray[i].Cities.length; j++) {
if (jsonArray[i].Cities[j].Id == parseInt(city)) {
state = jsonArray[i].Id;
break;
}
}
if (state) {
fillCity(jsonArray[i].Cities);
break;
}
}
$("#ddlState").val(state);
$("#ddlCity").val(city);
}
function fillCity(obj) {
var html = '<option value="0">Select City</option>';
$(obj).each(function () {
html += '<option value="' + this.Id + '">' + this.Name + '</option>'
});
$("#ddlCity").html(html);
}
function deleteSuccess(responce) {
alert("record deleted successfully");
$("tr[data-id='" + responce + "']").remove();
}
function insertSuccess() {
alert("Record saved successfully");
clearValues();
}
function showLoader() {
$("#overlay").show();
}
function hideLoader() {
$("#overlay").hide();
}
</script>
}
<h3>Add Personal Detail</h3>
#using (Ajax.BeginForm("SavePersonDetail", "Home", new AjaxOptions { HttpMethod = "POST", UpdateTargetId = "personList" ,OnSuccess="insertSuccess",OnBegin="showLoader",OnComplete="hideLoader"}))
{
#Html.HiddenFor(m => m.Id);
<ol class="round">
<li>
#Html.LabelFor(m => m.FirstName)
#Html.TextBoxFor(m => m.FirstName, new { id = "txtfirstName" })
#Html.ValidationMessageFor(m => m.FirstName)
</li>
<li>
#Html.LabelFor(m => m.LastName)
#Html.TextBoxFor(m => m.LastName, new { id = "txtlastName" })
#Html.ValidationMessageFor(m => m.LastName)
</li>
<li>
#Html.LabelFor(m => m.Email)
#Html.TextBoxFor(m => m.Email, new { id = "txtemail" })
#Html.ValidationMessageFor(m => m.Email)
</li>
<li>
#Html.Label("State")
#Html.DropDownList("State", States, "Select State", new { onchange = "loadCities(this)", id = "ddlState" })
</li>
<li>
#Html.LabelFor(m => m.CityId)
#Html.DropDownListFor(m => m.CityId, Cities, "Select City", new { id = "ddlCity" })
#Html.ValidationMessageFor(m => m.CityId)
</li>
</ol>
<input type="submit" value="Save" />
<input type="button" value="Cancel" onclick="clearValues();"/>
}
<h2>
Person List
</h2>
<div style="position:fixed;text-align:center;top:0;bottom:0;left:0;right:0;z-index:10;background-color:black;opacity:0.6;display:none;" id="overlay">
<img style="position:relative;top:370px" src="~/Images/ajax-loader.gif" />
</div>
<div id="personList">
#Html.Partial("_personDetail", persons)
</div>

You approach using ajax is fine although I would recommend a few better practices including using a view model with properties for StateID, CityID StateList and CityList, and using Unobtrusive JavaScript rather than polluting you markup with behavior, and generating the first ("please select") option with a null value rather than 0 so it can be used with the [Required] attribute
HTML
#Html.DropDownList(m => m.StateID, States, "Select State") // remove the onchange
#Html.DropDownListFor(m => m.CityID, Cities, "Select City") // why change the default ID?
SCRIPT
var url = '#Url.Action("GetCities", "Home")'; // use the helper (dont hard code)
var cities = $('#CityID'); // cache the element
$('#StateID').change(function() {
$.getJSON(url, { id: $(this).val() }, function(response) {
// clear and add default (null) option
cities.empty().append($('<option></option>').val('').text('Please select'));
$.each(response, function(index, item) {
cities.append($('<option></option>').val(item.Value).text(item.Text));
});
});
});
If you were rendering multiple items (say you were asking the user to select their last 10 cities they visited), you can cache the result of the first call to avoid repeated calls where their selections may include cities from the same state.
var cache = {};
$('#StateID').change(function() {
var selectedState = $(this).val();
if (cache[selectedState]) {
// render the options from the cache
} else {
$.getJSON(url, { id: selectedState }, function(response) {
// add to cache
cache[selectedState] = response;
.....
});
}
});
Finally, in response to your comments regarding doing it without ajax, you can pass all the cities to the view and assign them to a javascript array. I would only recommend this if you have a few countries, each with a few cities. Its a matter of balancing the slight extra initial load time vs the slight delay in making the ajax call.
In the controller
model.CityList = db.Cities.Select(d => new { City = d.CountryID, Text = d.CityName, Value = d.Id }).ToList();
In the view (script)
// assign all cities to javascript array
var allCities= JSON.parse('#Html.Raw(Json.Encode(Model.CityList))');
$('#StateID').change(function() {
var selectedState = $(this).val();
var cities = $.grep(allCities, function(item, index) {
return item.CountryID == selectedState;
});
// build options based on value of cities
});

This is a correct approach, but you can simplify your javascript:
function loadCities(obj) {
$.getJSON("/Home/GetCities", function (data) {
var html = '<option value="0">Select City</option>';
$(data).each(function () {
html += '<option value="'+this.Value+'">'+this.Text+'</option>'
});
$("#ddlCity").html(html);
});
}
Further possible simplification:
Add the default item (Select City) server-side, so your javascript will be smaller.

Here's how I'd do it without the page refresh, assuming the list of cities isn't too long.
I'm assuming you can create a GetStatesAndCities method to return a Dictionary.
public ActionResult Index()
{
Dictionary<string, List<String>> statesAndCities = GetStatesAndCities();
ViewBag.StatesAndCities = Json(statesAndCities);
}
Then in the view:
var states = JSON.parse(#ViewBag.StatesAndCities);
function loadCities(obj) {
var cities = states[$(obj).val()];
var html = '<option value="0">Select City</option>';
$(cities).each(function () {
html += '<option value="'+this.Value+'">'+this.Text+'</option>'
});
$("#ddlCity").html(html);
}
This way when the state is changed the cities field with update immediately with no need for callback.

disclaimer: This is not a code answer, there are plenty other answers.
I think best way to keep yourself happy to seperate UI pages from data => turn them into API calls:
/GetCities
/GetStates
Now you can simply leave the select's empty on Razor rendering the page. And use a Jquery/Bootstrap plugin to create an AJAX select box.
This way when the user stops typing his search, this search string can than be send with the AJAX call (eg: /GetStates?search=test) and then a small result set can be send back to the website.
This gives:
Better separation in serveside code
Better User eXperience.
Smaller page loads (since you no longer send all the options to user when he requests the page, only when he opens the select box).

How about using Knockout?
Knockout is a JavaScript library that helps you to create rich, responsive display and editor user interfaces with a clean underlying data model
You have to use ajax for your cities. But with knockout you dont need to write
var html = '<option value="0">Select City</option>';
$(responce).each(function () {
html += '<option value="'+this.Value+'">'+this.Text+'</option>'});
$("#ddlCity").html(html);
in your javascript.Knockout makes it simple.
You can simply write:
function CityModel() {
var self = this; // that means this CityModel
self.cities = ko.observableArray([]);
self.getCities = function () {
$.ajax({
url: "/Home/GetCities",
data: { id: $(obj).val() },
contentType: "application/json",
success: self.cities
});
}
}
ko.applyBindings(new CityModel());
thats all. But you have to bind your data into html elements.
Instead of using :
#Html.DropDownListFor(m => m.CityId, Cities, "Select City", new { id="ddlCity"})
You can use:
<select data-bind="options:cities,optionsValue:"Id",optionsText:"CityName",optionsCaption:"Select City""></select>
or you can mix razor and knockout:
#Html.DropDownListFor(m => m.CityId, Cities, "Select City", new { id="ddlCity",data_bind:"options:cities,optionsValue:\"Id\",optionsText:\"CityName\""})
One more thing you have to call GetCities when State changes, you can :
#Html.DropDownList("State", States, "Select State", new {data_bind:"event:\"change\":\"$root.GetCities\""})
Dont be scare with \"\" things this because " is an escape character and we have to say to razor i want to use " by using \ before it.
You can find more info about knockout :Knockout
And mixing with razor: Razor and Knockout
Ps: yes using knockout is suspend us from Razor and Mvc. You have to write another ViewModel . But like this situations ko is helpful. Mixing razor and knockout is another option for you.

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);
}
}