Develop Reference

How to manually select an item using AJAX, Select2 and the "val" function

Trying to figure out how to change the selected item of a select2 box after the page loads for the first time (and after it has loaded data from a ajax api call)
I tried using the below, but I cant get them to call after the ajax data has loaded?
$series2.val('2');
$series2.trigger('change');
The documentation says that it cannot be done using the val function (see here https://select2.org/programmatic-control/add-select-clear-items) and I do not want to do this with a custom API call that provides a "selected" value - as this does not work with templating.
This is NOT a duplicate of Select2 auto trigger event change
var $make2 = $(".make2");
var $series2 = $(".series2");
$make2.select2().on('change', function() {
$series2.empty();
if ($make2.val() !== null) {
$.ajax({
url: "{{ url('/') }}" + "/api/series/" + $make2.val(),
type: 'GET',
dataType: 'json',
async: true,
success: function(data) {
$series2.select2({
data: data,
templateSelection: function(result) {
return result['text'];
},
templateResult: function(result) {
if (!result['id']) {
return result['text'];
};
var final =
'<div>' +
'<strong>' + result['text'] + '</strong>' +
'<ul class="list-unstyled">' +
'<li><em>' + result['make'] + '</em></li>' +
'<li><em>' + result['category'] + '</em></li>' +
'</ul>' +
'</div>';
return final;
},
escapeMarkup: function(result) {
return result;
},
});
}
});
}
}).trigger('change');
});

Display JSON Result Upon Button Click ASP.NET MVC

Hi I have this code in my controller:
[HttpPost]
public JsonResult CalculateAndSaveToDB(BMICalculation CalculateModel)
{
if (ModelState.IsValid)
{
CalculateModel.Id = User.Identity.GetUserId();
CalculateModel.Date = System.DateTime.Now;
CalculateModel.BMICalc = CalculateModel.CalculateMyBMI(CalculateModel.Weight, CalculateModel.Height);
CalculateModel.BMIMeaning = CalculateModel.BMIInfo(CalculateModel.BMICalc);
db.BMICalculations.Add(CalculateModel);
db.SaveChanges();
}
return Json(new {CalculatedBMI = CalculateModel.BMICalc.ToString(), CalculatedBMIMeaning = CalculateModel.BMIMeaning.ToString() }, JsonRequestBehavior.AllowGet);
}
I would like to display CalculatedModel.BMICalc and CalculatedModel.BMIMeaning on the page using this JavaScript:
$('#good').click(function () {
var request = new BMICalculation();
$.ajax({
url: "CalculateAndSaveToDB",
dataType: 'json',
contentType: "application/json",
type: "POST",
data: JSON.stringify(request),
success: function (response) {
var div = $('#ajaxDiv');
div.html("<br/> " + "<b>" + "Your BMI Calculations: " + "</b>");
printBMI(div, response);
},
});
});
function printBMI(div, data) {
div.append("<br/>" + "You are " + response.CalculatedBMI + ".");
div.append("<br/>" + "You exact BMI is: " + response.CalculatedBMIMeaning + ".");
};
Nothing happens however when I do the button click. The correct data from form goes correctly into DB. My Chrome debugger says however that CalculateAndSaveToDB isn't found 404 error. Please help.

Try to return false at the end of your click function.
$('#good').click(function () {
//Your code
return false;
});
Also I can see an error in your printBMI function. There is not reference to the variable "response". It should be "data"
function printBMI(div, data) {
div.append("<br/>" + "You are " + data.CalculatedBMI + ".");
div.append("<br/>" + "You exact BMI is: " + data.CalculatedBMIMeaning + ".");
};

There might be several problems:
Your routing is not correct and the post-action cannot be invoked. I dont see any information about routing, so this might be a problem.
You do not return false, as suggested by PraveeReddy. If you dont do so, the browser follows the link of your button.
Just a hint: In such simple scenarios it can be easier to use $.load: http://api.jquery.com/load/

Returning Response in jquery ajax function

Getting problems in Response.d , based on the result which is returning by the checkusers() function I am saving the values. If the entered name is in already in database it should say "User already exists", if it is not in database it should create a new record.
But I am not getting the correct value from (response), I observed that Console.log(response.d) giving me correct values like 'true' or 'false'. I tried everything I know like-
changing async:"false"
var jqXHR = $.ajax({ and returning jqXHR.responseText
But none of they worked for me . Please help me with this.
submitHandler: function (form) {
var txtName = $("#txtName").val();
var txtEmail = $("#txtEmail").val();
var txtSurName = $("#txtSurName").val();
var txtMobile = $("#txtMobile").val();
var txtAddress = $("#txtAddress").val();
var obj = CheckUser();
if (obj == false) {
$.ajax({
type: "POST",
url: location.pathname + "/saveData",
data: "{Name:'" + txtName + "',SurName:'" + txtSurName + "',Email:'" + txtEmail + "',Mobile:'" + txtMobile + "',Address:'" + txtAddress + "'}",
contentType: "application/json; charset=utf-8",
datatype: "jsondata",
async: "true",
success: function (response) {
$(".errMsg ul").remove();
var myObject = eval('(' + response.d + ')');
if (myObject > 0) {
bindData();
$(".errMsg").append("<ul><li>Data saved successfully</li></ul>");
}
else {
$(".errMsg").append("<ul><li>Opppps something went wrong.</li></ul>");
}
$(".errMsg").show("slow");
clear();
},
error: function (response) {
alert(response.status + ' ' + response.statusText);
}
});
}
else {
$(".errMsg").append("<ul><li>User Already Exists </li></ul>");
$(".errMsg").show("slow");
}
}
});
$("#btnSave").click(function () {
$("#form1").submit()
});
});
checkusers function is:
function CheckUser() {
var EmpName = $("#txtName").val();
$.ajax({
type: "POST",
url: location.pathname + "/UserExist",
data: "{Name:'" + EmpName + "'}",
contentType: "application/json; charset=utf-8",
datatype: "jsondata",
async: "true",
success: function (response) {
console.log(response.d);
},
error: function (response) {
alert(response.status + ' ' + response.statusText);
}
});
}

Just because your database returns true or false doesn't mean this also gets returned by your CheckUser().
There are several options here:
Either you make a local variable in your CheckUser, Make your Ajax call synchronous, set the local variable to response.d in the success function and then return that local variable.
Another option is to work with Deferred objects and make your submithandler Ajax call wait for the Checkuser Ajax call to return;
A third option is to call your create ajax call from your success callback in your CheckUser Ajax call if the user isn't created yet.
I would recommend either option 2 or 3, because option 1 is not userfriendly.

Cannot read property 'length' of undefined jquery [duplicate]

This question already has answers here:
How do I return the response from an asynchronous call?
(41 answers)
Closed 9 years ago.
I am getting a list from C# web method with ajax (code below), the list is returned fine, but after the success method is done, it gives me an error - (Cannot read property 'length' of undefined) in the jquery (screenshot below)
Am I missing something ??
function getMainParentMenus() {
$.ajax({
type: "POST",
url: "/Mainpage.aspx/getLeftMainNavParentMenus",
data: "{}",
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (msg) {
alert(msg.d);
parentMenuss = msg.d;
}, //It goes to the screenshot below after this bracket
error: function (error) {
alert("An error has occured while fetching the Left Nav Parent Menus");
}
});
};
The method above is called by the below method.
var parentMenuss;
var listOfSubMenus;
function bindLeftNavMenu() {
// var parentMenus = getMainParentMenus();
getMainParentMenus();
var html = "<div id='accordian'> ddd";
$.each(parentMenuss, function () {
html += " <h3 class='accordianHeader' href='" + this['URL'] + "'>" + this['Title'] + "</h3> ";
alert("okK");
$.each(listOfSubMenus, function () {
html += "<div class='accordianContent'><a href='" + this['URL'] + "'>" + this['Title'] + "</a>";
});
});
html += "</div>";
$("#leftNavigationMenu").append(html);
};
EDIT :
the data in the alert in the first block of code above is displayed like so
and in the chrome debugger :

Because getMainParentMenus is using AJAX it is asynchronous. Your next line of code after calling getMainParentMenus will be executed before the .success part of your AJAX call, so it will be executed before parentMenuss has been populated.
There are a few ways you can tackle this, one way would be to pass the callback function to getMainParentMenus, something like this:
function getMainParentMenus(myCallback) {
$.ajax({
type: "POST",
url: "/Mainpage.aspx/getLeftMainNavParentMenus",
data: "{}",
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (msg) {
alert(msg.d);
parentMenuss = msg.d;
if (callback && typeof(callback)==="function") {
callback();
}
}, //It goes to the screenshot below after this bracket
error: function (error) {
alert("An error has occured while fetching the Left Nav Parent Menus");
}
});
};
Now you can call it like this:
var html = "<div id='accordian'> ddd";
getMainParentMenus(function() {
$.each(parentMenuss, function () {
html += " <h3 class='accordianHeader' href='" + this['URL'] + "'>" + this['Title'] + "</h3> ";
alert("okK");
$.each(listOfSubMenus, function () {
html += "<div class='accordianContent'><a href='" + this['URL'] + "'>" + this['Title'] + "</a>";
});
});
});

Your code for rendering the menus is being executed immediately after getMainParentMenus(); Javascript does not wait for the ajax call to complete before moving on to the next block. It is operating asynchronously, as others have mentioned in the comments.
Your code has to wait for the ajax call to complete before trying to display the data.
jQuery supports deferred execution and promises, so you can create code that will not execute until other code has completed. This is the preferred way of handling asynchronous operations.
Try this:
function getMainParentMenus() {
var request = $.ajax({
type: "POST",
url: "/Mainpage.aspx/getLeftMainNavParentMenus",
data: "{}",
contentType: "application/json; charset=utf-8",
dataType: "json"
}, //It goes to the screenshot below after this bracket
error: function (error) {
alert("An error has occured while fetching the Left Nav Parent Menus");
}
});
return request;
}
var parentMenuss;
var listOfSubMenus;
function bindLeftNavMenu() {
getMainParentMenus().success(function (result) {
var html = "<div id='accordian'> ddd";
$.each(parentMenuss, function () {
html += " <h3 class='accordianHeader' href='" + this['URL'] + "'>" + this['Title'] + "</h3> ";
alert("okK");
$.each(listOfSubMenus, function () {
html += "<div class='accordianContent'><a href='" + this['URL'] + "'>" + this['Title'] + "</a>";
});
});
html += "</div>";
$("#leftNavigationMenu").append(html);
});
}

Array and while loop: make unique clickable

I have an array (via ajax) that looks like this:
data[i].id: gives the id of user i
data[i].name: gives the name of user i
I want to output the array like this:
X Leonardo Da Vinci
X Albert Einstein
X William Shakespeare
...
The X is an image (x.gif) that must be clickable. On click, it must go to functiontwo(), passing the parameter data[i].id. Functiontwo will open a jquery dialog with the question "Delete id data[i].id"?
I know this can't be too hard to do, but I can't seem to figure it out...
This is what I have so far:
function functionone() {
$.ajax({
type : 'POST',
url : 'post.php',
dataType : 'json',
success : function(data){
var message = "";
var i = 0;
while (i < (data.length - 1))
{
var myvar = data[i].id;
message = message + "<div class=" + data[i].id + "><img src=x.gif></div>" + data[i].name + "<br />";
$('#somediv').html(message).fadeIn('fast');
$("." + data[i].id + "").click(function () {
functiontwo(myvar);
});
i++;
}
}
});
}
function functiontwo(id) {
...}
I know why this isn't working. Var i gets populated again and again in the while loop. When the while loop stops, i is just a number (in this case the array length), and the jquery becomes (for example):
$("." + data[4].id + "").click(function () {
functiontwo(myvar);
});
, making only the last X clickable.
How can I fix this?
Thanks a lot!!!
EDIT:
This is my 2nd function:
function functiontwo(id) {
$("#dialogdelete").dialog("open");
$('#submitbutton').click(function () {
$('#submitbutton').hide();
$('.loading').show();
$.ajax({
type : 'POST',
url : 'delete.php',
dataType : 'json',
data: {
id : id
},
success : function(data){
var mess = data;
$('.loading').hide();
$('#message').html(mess).fadeIn('fast');
}
});
//cancel the submit button default behaviours
return false;
});
}
In delete.php there's nothing special, I used $_POST['id'].

As I pointed out in my comment. The problem is the .click part. Either use bind, or use a class for all the elements, and a click-event like this $('.classnamehere').live('click',function () { // stuff });

function functionone() {
$.ajax({
type : 'POST',
url : 'post.php',
dataType : 'json',
success : function(data){
var message = "";
var i = 0;
while (i < (data.length - 1))
{
var myvar = data[i].id;
message = message + "<div class=\"clickable\" id=" + data[i].id + "><img src=x.gif></div>" + data[i].name + "<br />";
$('#somediv').html(message).fadeIn('fast');
i++;
}
}
});
}
$('.clickable').live('click',function () {
alert($(this).attr('id') + ' this is your ID');
});

The usual trick is create a separate function to create the event handler. The separate function will receive i as a parameter and the generated event will be able to keep this variable for itself
make_event_handler(name){
return function(){
functiontwo(name);
};
}
...
$("." + data[i].id + "").click( make_event_handler(myvar) );