Develop Reference

How to use select2 with multiple options using Razor and MVC

I am trying to create a multiple choice list using Select2, Razor and the MVC framework. My problem is that the object in the controller that receives the array input is always null. The front-end looks as follows:
<form class="form-horizontal" method="post" action="#Url.Action(MVC.Configurazione.Contatori.Edit())">
<div class="form-group">
<div class="col-lg-8">
<select class="form-control attributoSelect2" name="attributiSelezionati" value="#Model.AttributiSelezionati">
<option value="#Model.AttributiSelezionati" selected>#Model.AttributoDescrizione</option>
</select>
</div>
</div>
</form>
The action method "Edit", is the controller method that receives the array of chosen items from the drop-down list.
The Javascript is the following:
$('.attributoSelect2').select2({
placeholder: "Search attribute",
multiple: true,
allowClear: true,
minimumInputLength: 0,
ajax: {
dataType: 'json',
delay: 150,
url: "#Url.Action(MVC.Configurazione.Attributi.SearchAttrubutes())",
data: function (params) {
return {
search: params.term
};
},
processResults: function (data) {
return {
results: data.map(function (item) {
return {
id: item.Id,
text: item.Description
};
})
};
}
}
});
And finally the C# controller has an object that is expected to retrieve the data from the view and is defined:
public string[] AttributiSelezionati { get; set; }
and the HttpPost method that receives the data is:
[HttpPost]
public virtual ActionResult Edit(EditViewModel model) { }
Could someone give me some insight into what I am doing wrong and the areas that I should change in order to find the problem?

you class name error not attributoSelect2 is attributesSelect2 , I also make this mistake often. haha
<select class="form-control attributoSelect2" name="attributiSelezionati" value="#Model.AttributiSelezionati">
<option value="#Model.AttributiSelezionati" selected>#Model.AttributoDescrizione</option>
</select>

There are multiple reason for not being receiving data on server. First of all you need to change your select code as follow
#Html.DropDownList("attributiSelezionati", Model.AttributiSelezionati, new { #class = "form-control attributo select2" })
now go to console in browser and get the data of element to confirm that your code properly works in HTML & JS
After that you need to add attribute at your controller's action method as
[OverrideAuthorization]
[HttpPost]

You can try the following approach that has been used in some of our projects without any problem:
View:
#Html.DropDownListFor(m => m.StudentId, Enumerable.Empty<SelectListItem>(), "Select")
$(document).ready(function () {
var student = $("#StudentId");
//for Select2 Options: https://select2.github.io/options.html
student.select2({
language: "tr",//don't forget to add language script (select2/js/i18n/tr.js)
minimumInputLength: 0, //for listing all records > set 0
maximumInputLength: 20, //only allow terms up to 20 characters long
multiple: false,
placeholder: "Select",
allowClear: true,
tags: false, //prevent free text entry
width: "100%",
ajax: {
url: '/Grade/StudentLookup',
dataType: 'json',
delay: 250,
data: function (params) {
return {
query: params.term, //search term
page: params.page
};
},
processResults: function (data, page) {
var newData = [];
$.each(data, function (index, item) {
newData.push({
//id part present in data
id: item.Id,
//string to be displayed
text: item.Name + " " + item.Surname
});
});
return { results: newData };
},
cache: true
},
escapeMarkup: function (markup) { return markup; }
});
//You can simply listen to the select2:select event to get the selected item
student.on('select2:select', onSelect)
function onSelect(evt) {
console.log($(this).val());
}
//Event example for close event
student.on('select2:close', onClose)
function onClose(evt) {
console.log('Closed…');
}
});
Controller:
public ActionResult StudentLookup(string query)
{
var students = repository.Students.Select(m => new StudentViewModel
{
Id = m.Id,
Name = m.Name,
Surname = m.Surname
})
//if "query" is null, get all records
.Where(m => string.IsNullOrEmpty(query) || m.Name.StartsWith(query))
.OrderBy(m => m.Name);
return Json(students, JsonRequestBehavior.AllowGet);
}
Hope this helps...
Update:
Dropdown option groups:
<select>
<optgroup label="Group Name">
<option>Nested option</option>
</optgroup>
</select>
For more information have a look at https://select2.org/options.

Storing HTML form input in a JS object

I know there is a very similar question asked over here but my object hierarchy is different than the one in that question.
Anyways, I want to store the HTML form input data in to my JavaScript object. Here is my HTML form code:
<form id="newAuction">
<input id="title" name="title" required type="text" value="" />
<input id="edate" name="edate" required type="datetime" value="" />
<input id="minbid" name="minbid" required type="number" value="" />
<button class="btn btn-primary">Submit</button>
</form>
What I want is to get the values of these 3 inputs and store it in my JS object.
I know the proper JSON format needed to post the data to my API. (I tried POSTing with POSTman and I get a status 200, so it works). The proper format is:
{
"auction": {
"Title": "Auction1",
"EDate": "01/01/1990",
"MinBid": 30
},
"productIds": [1,2,3]
}
This is what my JS object looks like:
<script>
$(document).ready(function() {
var vm = {
auction: {},
productIds: []
};
//validation and posting to api
var validator = $("#newAuction").validate({
//assigning values
vm.auction.Title = document.getElementById('title').value;
vm.auction.MinBid = document.getElementById('minbid').value;
vm.auction.EDate = document.getElementById('edate').value;
vm.productIds.push(1);
submitHandler: function () {
$.ajax({
url: "/api/newAuction",
method: "post",
data: vm
})
.done(function () {
toastr.success("Auction Added to the db");
//setting the vm to a new vm to get rid of the old values
var vm = { auction: {}, productIds: [] };
validator.resetForm();
})
.fail(function () {
toastr.error("something wrong");
});
return false;
}
});
});
</script>
As you can see, I am using document.getElementById('title').value; to get the values and assign them but I'm getting the syntax error Expected : Comma expected
Not sure if this matters, but this is inside a .NET MVC5 project.

Move your value assignment set of codes inside submitHandler. Check the syntax of validate() https://jqueryvalidation.org/validate/
//validation and posting to api
var validator = $("#newAuction").validate({
submitHandler: function () {
//assigning values
vm.auction.Title = document.getElementById('title').value;
vm.auction.MinBid = document.getElementById('minbid').value;
vm.auction.EDate = document.getElementById('edate').value;
vm.productIds.push(1);
$.ajax({
url: "/api/newAuction",
method: "post",
data: vm
})
.done(function () {
toastr.success("Auction Added to the db");
//setting the vm to a new vm to get rid of the old values
var vm = { auction: {}, productIds: [] };
validator.resetForm();
})
.fail(function () {
toastr.error("something wrong");
});
return false;
}
});

Select2 can't change value

I am dynamically loading a Select2 input with Ajax. Everything works fine, however, when I try to select a different value, It won't change for some reason. Here's an example of my problem: https://gyazo.com/f9ad7c3ead5fcd1d62740cc44f8d9691
As you can see, the value doesn't change when I click on it. Why does this happen? Maybe it helps when I say that both the first value and the other value have an ID of 1 (its data from different tables in the database) but different texts... How can I make it work?
$('.partnersupplierselect').select2({
ajax: {
dataType: "json",
type: "POST",
data: function (params) {
var group = $(this).parent().parent();
var choice = group.find('.partnersupplier:radio:checked').val();
return {
term: params.term,
'_token': token,
'choice': choice
};
},
url: '{{asset('logs/create/bmi/getpartnerssuppliers')}}',
cache: true,
processResults: function (data) {
return {
results: data
};
}
},
"language": {
"noResults": function () {
return "Geen partners / leveranciers gevonden.";
}
},
escapeMarkup: function (markup) {
return markup;
}
});
$('.partnersupplier').on('change', function(){
var group = $(this).parent().parent();
group.find('.partnersupplierselect').select2('val', '');
group.find('.partnersupplierselect').select2('data', null);
});
Here's the HTML, but that shouldn't be the problem. But in case someone wants to see it:
<div class="group">
<label class="mdl-radio mdl-js-radio mdl-js-ripple-effect" for="partner">
{{Form::radio('partnersupplier', 'partner', true, array('class' => 'mdl-radio__button partnersupplier', 'id' => 'partner'))}}
<span class="mdl-radio__label">Test1 </span>
</label>
<label class="mdl-radio mdl-js-radio mdl-js-ripple-effect margin-radio" for="supplier">
{{Form::radio('partnersupplier', 'supplier', false, array('class' => 'mdl-radio__button partnersupplier', 'id' => 'supplier'))}}
<span class="mdl-radio__label">Test2 </span>
</label>
<div class="form-group selectdiv" >
<label for="yearlypartnersuppliermaintainance">Blablabla<br></label>
<select id="yearlypartnersuppliermaintainance" name="yearlypartnersuppliermaintainance" class="searchselect searchselectstyle partnersupplierselect">
</select>
</div>
</div>

I figured it out!
I changed:
$('.partnersupplier').on('change', function(){
var group = $(this).parent().parent();
group.find('.partnersupplierselect').select2('val', '');
group.find('.partnersupplierselect').select2('data', null);
});
to:
$('.partnersupplier').on('change', function(){
var group = $(this).parent().parent();
group.find('.partnersupplierselect').empty().trigger('change');
});
For some reason, this works and the first thing doesn't. Weird, but at least I got it working!

I want to filter in the list if the text box value is changed using knockout

I want to filter in the list if the text box value is changed if the
JSON Returned in Ajax call is as I am using two different model.
Filteration should show hide or just filter the data I am providing you the JSON data what I am getting from the ajax call. Thanks
Data = [{"code":"Grand Financial","cls":"Branch","Chk":true},{"code":"Joan Group","cls":"Branch","Chk":true}]
var searchModel, advisorGroupModel;
$(document).ready(function () {
$.ajax({
type: "GET",
url: '/ASPNET/Reports/GetAdvisorGroups',
dataType: "json",
success: function (data) {
advisorGroupModel = {
advisorGroup: ko.observableArray(data)
};
ko.applyBindings(advisorGroupModel, document.getElementById("advisorGroupModel"));
}
})
var searchModel = {
searchQuery: ko.observable('')
};
searchModel.searchHandle= ko.dependentObservable(function () {
var code = this.searchQuery().toLowerCase();
return ko.utils.arrayFilter(advisorGroupModel, function (beer) {
debugger;
return beer.code.toLowerCase().indexOf(code) >= 0;
});
console.log(search);
}, searchModel)
ko.applyBindings(searchModel, document.getElementById("searchModel"));
});
<div id="searchModel">
<input data-bind="value: searchQuery, valueUpdate: 'keyup'" />
<h6 data-bind="text: searchQuery"></h6>
</div>
<div class="CheckBoxListGroup" id="advisorGroupModel">
<ul data-bind="template: { name: 'advisorGroupTemplate', foreach: advisorGroup, as: 'singleAdvisorGroup' }"></ul>
<script type="text/html" id="advisorGroupTemplate">
<li>
<input type="checkbox" data-bind="attr: { value: code, id: code, checked: Chk }" name="GroupsSel">
<label data-bind="attr: { for: code }, text: '' + code + ' (' + cls + ')' "></label>
</li>
</script>
</div>

don't bind your display to the entire list, bind your display to a computed function that returns the filtered list or returns all items when there are no filters.
then on your keyup call your filterlist function that filters the list removing the ones that do not match your filter

jQuery Validate Plugin - How to create a simple custom rule?

How do you create a simple, custom rule using the jQuery Validate plugin (using addMethod) that doesn't use a regex?
For example, what function would create a rule that validates only if at least one of a group of checkboxes is checked?

You can create a simple rule by doing something like this:
jQuery.validator.addMethod("greaterThanZero", function(value, element) {
return this.optional(element) || (parseFloat(value) > 0);
}, "* Amount must be greater than zero");
And then applying this like so:
$('validatorElement').validate({
rules : {
amount : { greaterThanZero : true }
}
});
Just change the contents of the 'addMethod' to validate your checkboxes.

$(document).ready(function(){
var response;
$.validator.addMethod(
"uniqueUserName",
function(value, element) {
$.ajax({
type: "POST",
url: "http://"+location.host+"/checkUser.php",
data: "checkUsername="+value,
dataType:"html",
success: function(msg)
{
//If username exists, set response to true
response = ( msg == 'true' ) ? true : false;
}
});
return response;
},
"Username is Already Taken"
);
$("#regFormPart1").validate({
username: {
required: true,
minlength: 8,
uniqueUserName: true
},
messages: {
username: {
required: "Username is required",
minlength: "Username must be at least 8 characters",
uniqueUserName: "This Username is taken already"
}
}
});
});

// add a method. calls one built-in method, too.
jQuery.validator.addMethod("optdate", function(value, element) {
return jQuery.validator.methods['date'].call(
this,value,element
)||value==("0000/00/00");
}, "Please enter a valid date."
);
// connect it to a css class
jQuery.validator.addClassRules({
optdate : { optdate : true }
});

Custom Rule and data attribute
You are able to create a custom rule and attach it to an element using the data attribute using the syntax data-rule-rulename="true";
So to check if at least one of a group of checkboxes is checked:
data-rule-oneormorechecked
<input type="checkbox" name="colours[]" value="red" data-rule-oneormorechecked="true" />
addMethod
$.validator.addMethod("oneormorechecked", function(value, element) {
return $('input[name="' + element.name + '"]:checked').length > 0;
}, "Atleast 1 must be selected");
And you can also override the message of a rule (ie: Atleast 1 must be selected) by using the syntax data-msg-rulename="my new message".
NOTE
If you use the data-rule-rulename method then you will need to make sure the rule name is all lowercase. This is because the jQuery validation function dataRules applies .toLowerCase() to compare and the HTML5 spec does not allow uppercase.
Working Example
$.validator.addMethod("oneormorechecked", function(value, element) {
return $('input[name="' + element.name + '"]:checked').length > 0;
}, "Atleast 1 must be selected");
$('.validate').validate();
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery-validate/1.14.0/jquery.validate.min.js"></script>
<form class="validate">
red<input type="checkbox" name="colours[]" value="red" data-rule-oneormorechecked="true" data-msg-oneormorechecked="Check one or more!" /><br/>
blue<input type="checkbox" name="colours[]" value="blue" /><br/>
green<input type="checkbox" name="colours[]" value="green" /><br/>
<input type="submit" value="submit"/>
</form>

Thanks, it worked!
Here's the final code:
$.validator.addMethod("greaterThanZero", function(value, element) {
var the_list_array = $("#some_form .super_item:checked");
return the_list_array.length > 0;
}, "* Please check at least one check box");

You can add a custom rule like this:
$.validator.addMethod(
'booleanRequired',
function (value, element, requiredValue) {
return value === requiredValue;
},
'Please check your input.'
);
And add it as a rule like this:
PhoneToggle: {
booleanRequired: 'on'
}

For this case: user signup form, user must choose a username that is not taken.
This means we have to create a customized validation rule, which will send async http request with remote server.
create a input element in your html:
<input name="user_name" type="text" >
declare your form validation rules:
$("form").validate({
rules: {
'user_name': {
// here jquery validate will start a GET request, to
// /interface/users/is_username_valid?user_name=<input_value>
// the response should be "raw text", with content "true" or "false" only
remote: '/interface/users/is_username_valid'
},
},
the remote code should be like:
class Interface::UsersController < ActionController::Base
def is_username_valid
render :text => !User.exists?(:user_name => params[:user_name])
end
end

Step 1 Included the cdn like
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<script src="http://ajax.aspnetcdn.com/ajax/jquery.validate/1.11.1/jquery.validate.min.js"></script>
Step 2 Code Like
$(document).ready(function(){
$("#submit").click(function () {
$('#myform').validate({ // initialize the plugin
rules: {
id: {
required: true,
email: true
},
password: {
required: true,
minlength: 1
}
},
messages: {
id: {
required: "Enter Email Id"
},
password: {
required: "Enter Email Password"
}
},
submitHandler: function (form) { // for demo
alert('valid form submitted'); // for demo
return false; // for demo
}
});
}):
});