I am working on a web project that involves a cross-domain call, and I decided to use Knockout.js and ASP.NET Web Api. I used the Single Page Application template in VS 2012, and implemented the Knockout class as it is. The page works great when I make JSON call from the same domain, but when I try using JSONP from the remote server the knockout does not seem to bind the data. I can see the JSON data received from the remote while making JSONP call, but knockout cannot bind the data.
Here is my JavaScript ViewModel classes:
window.storyApp.storyListViewModel = (function (ko, datacontext) {
//Data
var self = this;
self.storyLists = ko.observableArray();
self.selectedStory = ko.observable();
self.error = ko.observable();
//Operations
//Load initial state from the server, convert it to Story instances, then populate self
datacontext.getStoryLists(storyLists, error); // load update stories
self.selectStory = function (s) {
selectedStory(s); $("#showStoryItem").click(); window.scrollTo(0, 0);
storyItem = s;
}
//append id to the hash for navigating to anchor tag
self.backToStory = function () {
window.location.hash = storyItem.id;
}
self.loadStories = function () {
datacontext.getStoryLists(storyLists, error); // load update stories
}
return {
storyLists: self.storyLists,
error: self.error,
selectStory: self.selectStory
};
})(ko, storyApp.datacontext);
// Initiate the Knockout bindings
ko.applyBindings(window.storyApp.storyListViewModel);
And my DataContext class as below:
window.storyApp = window.storyApp || {};
window.storyApp.datacontext = (function (ko) {
var datacontext = {
getStoryLists: getStoryLists
};
return datacontext;
function getStoryLists(storyListsObservable, errorObservable) {
return ajaxRequest("get", storyListUrl())
.done(getSucceeded)
.fail(getFailed);
function getSucceeded(data) {
var mappedStoryLists = $.map(data, function (list) { return new createStoryList(list); });
storyListsObservable(mappedStoryLists);
}
function getFailed() {
errorObservable("Error retrieving stories lists.");
}
function createStoryList(data) {
return new datacontext.StoryList(data); // TodoList is injected by model.js
}
}
// Private
function clearErrorMessage(entity) {
entity.ErrorMessage(null);
}
function ajaxRequest(type, url, data) { // Ajax helper
var options = {
dataType: "JSONP",
contentType: "application/json",
cache: false,
type: type,
data: ko.toJSON(data)
};
return $.ajax(url, options);
}
// routes
function storyListUrl(id) {
return "http://secure.regis.edu/insite_webapi/api/story/" + (id || "");
}
})(ko);
This page: http://insite.regis.edu/insite/index.html makes the cross-domain call to secure.regis.edu, and it is not working. However the same page on secure.regis.eduinsite/index.html making JSON call works just fine.
What am I doing wrong? Any help will be greatly appreciated.
Thanks for those provided help.
I manage to solve the issue by adding WebApiContrib.Formatting.Jsonp class to my WebApi project as explained in https://github.com/WebApiContrib/WebApiContrib.Formatting.Jsonp, and making a slight modification to my jQuery Ajax helper class as below:
function ajaxRequest(type, url, data, callbackWrapper) { // Ajax helper
var options = {
dataType: "jsonp",
crossDomain : true,
type: type,
jsonp: "callback",
jsonpCallback: callbackWrapper,
data: ko.toJSON(data)
};
return $.ajax(url, options);
}
Everything worked as a charm.
I suggest the following:
Create a simplified example (without Knockout) that just makes the AJAX call with simple, alert-style success and error callbacks. Affirm that it is throwing an error in the cross-domain case.
Check the following link: parsererror after jQuery.ajax request with jsonp content type. If that doesn't tell you enough, search the Web (and StackOverflow) for information on jQuery JSONP parserrors and callbacks.
If you're still stuck, and you've done #1 and seen what I expect you will see, re-write this post with your simplified example, and remove any references to Knockout (in title, tags). I know Knockout, but I don't know JSONP, and the folks who know JSONP don't seem to be touching this, so I think this question is reaching the wrong audience. Changing the title and tags to emphasize the JSONP/cross-domain aspect may get you the help you need.
Related
I am simply trying to load data when my app starts. However, the view loads faster than the http request(of course). I want to refresh my view once my data has been properly loaded because that data defines my view.
I've tried $rootScope.apply from inside the factory where I do my http request, and I also tried directly doing the http request in my controller again with $scope.apply, and neither one worked as they both gave me "$digest already in progress"
Any idea how can I set up my code to make my views refresh on data load? I will be having several different http requests and I would like to know how to set them up properly! I would really appreciate any input!
Here is some of the code I am working with.
app.factory('HttpRequestFactory', function($http, $q) {
var HttpRequestFactory = {
async: function(url, params) {
var deferred = $q.defer();
$http({
url: url,
method: post,
params: params
})
.success(function(data, status, headers, config) {
deferred.resolve(data);
})
.error(function(data, status, headers, config) {
deferred.reject("An error occurred");
});
return deferred.promise;
}
};
return HttpRequestFactory;
});
Factory
function initializeAll(){
HttpRequestFactory.async('../api', {action: 'getall'}).then(function(data) {
//$rootScope.$apply(function () {
allData = data;
//});
angular.forEach(allData, function(value, index){
console.log('Voala!');
});
});
}
Controller calling the factory's function initializeAll()
app.controller("MainController", ["$scope", "$rootScope","MyFactory",
function($scope, $rootScope, MyFactory){
MyFactory.initializeAll();
}
]);
Oh my !
You got the f** matter with AngularJS !
In fact you have to do a "safeApply" like that for example :
$rootScope.safeApply = function(fn) {
var phase = this.$root.$$phase;
if(phase == '$apply' || phase == '$digest') {
if(fn && (typeof(fn) === 'function')) {
fn();
}
} else {
this.$apply(fn);
}
};
In AngularJS you can only have one $apply or $digest loop at the same time.
For details on these loops look at the docs :
http://docs.angularjs.org/guide/concepts
It will explain what is the $apply loop and you'll understand a lot of things about the two-way-data-binding in AngularJS
Hope it helps.
Don't use $apply: use $watch.
Calling $apply is (almost) always the wrong thing to do. The only time you should ever be calling it is if you've triggered a change outside of an 'angular' method; here, since the trigger occurs in an angular $http request, you can't call $apply because it's already being done at that moment by the $http block. Instead, what you want to do is $watch.
Official Doc for $scope.$watch() here
This will let you watch an object and update whenever it changes. I assume that your view is based on allData and you want it to update immediately; if you're using an ng method, then the watch is automatically setup for you and no more work should be needed. If you're using allData yourself inside a controller, you can write the watch in that controller like this:
$scope.$watch(function thingYouWantToWatch(){
return <accessor call to allData here>;
},
function whatToDoOnChange(newValue, oldValue){
$scope.myCoolThing = newValue; //this is the newValue of allData, or whatever you're watching.
}
);
I am working in ASP.Net MVC. I have following Javascript code in which i am calling a controller-method which returns a view. I want to send parameters to a controller method which re
function fun(p1,p2)
{
// code here to call controller method which returns view
}
public ActionResult ProblemDetails(p1,p2)
{
// here goes some code.
return View();
}
Please tell me the code which can be used to call controller and send parameters too.
Action Method
public ActionResult SendStream(string a, string b)
{
}
JQuery/JSON
Please note that Get Verb will not support complex Data parameters due to it's Query string length constraint. So use POST Verb instead of GET Verb while sending large data
$.ajax({
url: url,
data: JSON.stringify({ a: "a", b: "b" }), //Two String Parameters
type: 'GET', //For Submit, use POST
contentType: 'application/json, charset=utf-8',
dataType: 'json'
}).done(function (data) {
//Success Callback
}).fail(function (data) {
//Failed Callback
}).always(function(data) {
//Request completed Callback
});
Are you perhaps looking to return a Partial View? You can use jQuery ajax to post to a controller method that returns a Partial View (html). You can then render that HTML on the page.
http://mazharkaunain.blogspot.com/2011/04/aspnet-mvc-render-partial-view-using.html
jQuery.get is the shorthand way to achieve this.
function fun(p1,p2)
{
var url = '/controller/ProblemDetails?p1=' + p1 + '&p2=' + p2;
$.get(url, function (data) {
// data will be your response as html
});
}
I might also suggest to have the action return PartialView() instead of View() since you will not return the layout along with the response. It all depends on your intentions for the returned html.
There are several ways to do it.
For example Ajax:
Quick note first: Make sure that in your MVC routing configuration you have a route configured to reflect the following url below:
function fun(p1,p2)
{
var url = '/ControllerName/ProblemDetails?p1=p1&p2=p2' //url to your action method
$.ajax({
url:url,
type:'post' or 'get', //(depending on how you're doing this. If post you can pass data internally instead of query string ),
dataType:'html', //(for example)
success:function(data){
//data here will contain your View info so you can append it do div for example. You can use JQuery .html() function for that
error: function (xhr) {
//catch error
}
}
})
}
Another way, in case if you want to load your View data to DIV is to use JQUery functions such as .load();
function fun(p1,p2)
{
var url = '/ControllerName/ProblemDetails?p1=p1&p2=p2';
$('#YourDivTagForExample').load(url);
}
$.ajax call can also be abbriviated to $.get, $.post or $.getJSON depending on what kind of a call you want to make to your action method. There is a lot more to it too.
Finally make sure to take a look at this answer. Your question was actually already answered in full:
Correct way to handle Ajax calls in ASP.Net MVC 3
Use JSONResult instead of ActionResult and Manipulate return data in javascript.
I have decided to not use ember-data as it's not production ready and still changing. My app only needs to make a few ajax requests anyway so it shouldn't make too big of a difference. I am having trouble understanding how to handle an ajax promise response.
When my user loads the app they already have an authenticated session. I am trying to ping the server for that users info and display it in my template. It seems my template is rendered before my ajax request returns results and then does not update with the promise.
// route
App.ApplicationRoute = Ember.Route.extend({
setupController: function(){
this.set("currentUser", App.User.getCurrentUser());
}
});
// model
App.User = Ember.Object.extend({
email_address: '',
name_first: '',
name_last: '',
name_full: function() {
return this.get('name_first') + ' ' + this.get('name_last');
}.property('name_first', 'name_last')
});
App.User.reopenClass({
getCurrentUser: function() {
return $.ajax({
url: "/api/get_current_user",
type: "POST",
data: JSON.stringify({})
}).then(function(response) {
return response;
});
}
});
In my template:
<h1> Hey, {{App.currentUser.name_first}}</h1>
How would I update the template when I receive a response or delay rendering until I have a response?
Actually the answer is quite easy: You do not need to use a promise. Instead just return an empty object. Your code could look like this:
App.User.reopenClass({
getCurrentUser: function() {
var user = App.User.create({}); //create an empty object
$.ajax({
url: "/api/get_current_user",
type: "POST",
data: JSON.stringify({})
}).then(function(response) {
user.setProperties(response); //fill the object with your JSON response
});
return user;
}
});
What is happening here?
You create an empty object.
You make an asynchronous call to your API...
... and in your success callback you fill your empty object.
You return your user object.
Note: What is really happening? The flow mentioned above is not the sequence in which those actions are happening. In reality the points 1,2 and 4 are performed first. Then some time later, when the response returns from your server, 3 is executed. So the real flow of actions is: 1 -> 2 -> 4 -> 3.
So the general rule is to always return an object that enables Ember to do its logic. No values will be displayed first in your case and once your object is filled Ember will start do its magic and auto update your templates. No hard work needs to be done on your side!
Going beyond the initial question: How would one do this with an array?
Following this general rule, you would return an empty array. Here a little example, which assumes, that you might like to get all users from your backend:
App.User.reopenClass({
getAllUsers: function() {
var users = []; //create an empty array
$.ajax({
url: "/api/get_users",
}).then(function(response) {
response.forEach(function(user){
var model = App.User.create(user);
users.addObject(model); //fill your array step by step
});
});
return users;
}
});
I'd use Ember.Deferred instead of returning an empty array as mentioned before.
App.User.reopenClass({
getAllUsers: function() {
var dfd = Ember.Deferred.create();
var users = [];
$.ajax({
url: "/api/get_users",
}).then(function(response) {
response.forEach(function(user){
var model = App.User.create(user);
users.addObject(model);
});
dfd.resolve(users);
});
return dfd;
}
});
In your model hook all you have to do is this
model: function(){
return App.User.getAllUsers();
}
Ember is smart enought and knows how to handle the promise you return, once it's resolved the model will be correctly set, you can also return a jQuery promise but it will give you some weird behavior.
You can as well set the current user as the model for your ApplicationRoute like so:
App.ApplicationRoute = Ember.Route.extend({
model: function() {
return App.User.getCurrentUser();
}
});
Since getCurrentUser() returns a promise, the transition will suspend until the promise either fulfills or rejects.
This is handy because by the time transition is finished your model is initialized and you will see it rendered in the template.
You can read up more about async routing in Ember guides.
Im creating a simple "Was this useful?" form with Yes and No objects- Using ASP.net webforms.
I need the submission to be done via ajax using jquery, to prevent a user from voting multiple times on the same page.. currently i have two methods Like_Click and Dislike_click in the C# code behind the page in question.
Can anyone give me some pointers on or a link to any suitable walkthroughs for simple ajax via jquery (I'm new to ajax!)
Ive looked at using the [WebMethod] identifier on each of the methods but do not really understand this method fully.
thanks
You are probably looking for jQuery's post function. Check out the examples. You'll want to do something along the lines of:
$('.myForm').submit(function(){ //define a handler for the submit event of the form
$.post($(this).attr('action'), {useful: true}); //send data via ajax
return false; //prevents the form from submitting via a normal web request
});
You can try something like below
<script type="text/javascript">
$(function () {
$('#btnSubmit').click(function () {
var like = $('#Like').val();
var dislike = $('#Dislike').val();
if (name != '' && email != '') {
$.ajax
({
type: 'POST',
url: 'Home.aspx/UpdateDB', //UpdateDB is declared as WebMethod
async: false,
data: "{'like':'" + like + "','dislike':'" + dislike + "'}",
contentType: 'application/json; charset =utf-8',
success: function (data) {
var obj = data.d;
if (obj == 'true') {
$('#Like').val('');
$('#Dislike').val('');
alert("Data Saved Successfully");
}
},
error: function (result) {
alert("Error Occured, Try Again");
}
});
}
})
});
</script>
Webmethod is shown below
[WebMethod]
public static string UpdateDB(string like, string dislike)
{
//Add your stuff
}
take a look more details here Call WebMethod from jquery in ASP.NET
I need a periodic refresh of .Net's partial view. It is working with Ajax.ActionLink, is there a similar feature for periodic refresh? Can I do it without using jQuery?
Zen, you could do it by a code like this:
function loadPartialView() {
$.ajax({
url: "#Url.Action("ActionName", "ControllerName")",
type: 'GET', // <-- make a async request by GET
dataType: 'html', // <-- to expect an html response
success: function(result) {
$('#YourDiv').html(result);
}
});
}
$(function() {
loadPartialView(); // first time
// re-call the function each 5 seconds
window.setInterval("loadPartialView()", 5000);
});
Remember your Action should return a PartialView.
I hope it helps you!
Maybe this can help you. Which version of MVC are you using? You can set a specified time interval for a helper method. This is the only way I've seen without using js.
Try this.
$(document).ready(function () {
var url = "#(Html.Raw(Url.Action("ActionName", "ControllerName")))";
$("#PartialViewDivId").load(url);
setInterval(function () {
var url = "#(Html.Raw(Url.Action("ActionName", "ControllerName")))";
$("#PartialViewDivId").load(url);
}, 30000); //Refreshes every 30 seconds
$.ajaxSetup({ cache: false }); //Turn off caching
});
It makes an initial call to load the div, and then subsequent calls are on a 30 second interval.
In the controller section you can update the object and pass the object to the partial view.
public class ControllerName: Controller
{
public ActionResult ActionName()
{
.
. // code for update object
.
return PartialView("PartialViewName", updatedObject);
}
}