I'm using MVC5 and originally had a standard MVC implementation with manual paging and all was well. Except, when I showed it to my friend, he's like "What are all these number things down here?" (referring to the paging buttons, in his defense he was using his smart phone). It was then I decided infinite scroll would be much better.
After what seems like a million google searches, most the solutions (as well as ALL the solutions that I can actually understand) use json and jquery. Since I was using Troy Goode's PagedList already to do the manual paging, I went with his recommended solution here:
How Can I Convert My Paging Functionality To Use AJAX Insead?
And, I came up with this using json, jquery and handlebars:
<div id="incidentsList"></div>
<div id="incidentsWaypoint">.</div>
#section Scripts{
<script id="incident-template" type="text/x-handlebars-template">
<div class="tRoot">
<div class="tRow">
<div class="index-title">
{{Title}}
</div>
</div>
<div class="tRow">
<div class="index-description">
{{Description}}
</div>
</div>
<div class="tRow">
<div class="pCount">
Count: {{Count}}
</div>
<div class="pSend">
!!!!Partial View Here!!!!
</div>
</div>
</div>
</script>
<script type="text/javascript" src="/Scripts/handlebars-v3.0.3.js"></script>
<script type="text/javascript" src="/Scripts/waypoints.min.js"></script>
<script type="text/javascript">
var source = $("#incident-template").html();
var template = Handlebars.compile(source);
$(function () {
var page = 1;
var $incdiv = $('#incidentsList');
var $waypoint = $('#incidentsWaypoint');
var opts = { offset: '100%' };
$waypoint.waypoint(function () {
$waypoint.waypoint('remove');
$.getJSON('#Url.Action("AjaxPage", "Incidents")', { page: page++ }, function(incidents) {
$.each(incidents, function (index, incident) {
var pPartial = '#Html.Partial("_ProjectStatus", incident)';
//console.log(incident.Title);
//var context = { IncidentId: incident.IncidentId, Title: incident.Title, Description: incident.Description, Count: incident.Count };
var context = incident;
$incdiv.append(template(context));
});
$waypoint.waypoint(opts);
});
}, { offset: '100%' });
});
</script>
}
It works well as far as I can tell, except that I now seem to have lost the ability to use razor html helpers and such, more specifically that #Html.Partial("_ProjectStatus", incident) that has logic like:
if (!Model.IsOwner(Context.User.Identity.Name))
{
if (Model.IsSent(userId))
{
So, I can't just generate straight html for that...
I was going to chop the handlebars template up into smaller templates and then hopefully use the razor helpers in jquery like I started with the var pPartial and then append it all together in the jquery code, but wanted to post it here first before I do all the work to see if I'm even on the right track, especially since (after many more searches) I haven't really found anyone trying to do this.
Therefore, my question(s) is (and I wouldn't expect them all answered, I'm just not sure what to ask and hoping someone can see what I'm trying to accomplish), will what I'm trying to do in the previous paragraph even work? Are razor helpers/logic out of the question in handlebars templates? Are there examples somewhere?...especially of someone who has a full implementation (i.e. something a little more complex than just a list where the example actually uses helpers/logic in it)? Is there another way to do infinite scroll that would allow me to keep my razor code or solely use partial views (or similar) with minimal jquery maybe?
As always, I appreciate any guidance. Thank you.
So far, I fixed it by moving my view logic (learned from nerddinner...which also makes me think of another question) to the controller, by simply adding the last two lines to my json result and returning them as bools:
var incidents = listPaged.Select(items => new
{
items.IncidentId,
items.Title,
items.Description,
items.Count,
IsOwner = items.IsOwner(userName), // this one
IsSent = items.IsSent(userId) //and this one
});
Then in handlebars, I did:
{{#unless IsOwner}}
{{#if IsSent}}
<div class="sent">Sent...</div>
{{else}}
<div class="sent">Not Sent...</div>
{{/if}}
{{/unless}}
I tried to do the partial view with #Html.Action and a few other things that were really straining my mind how they could even possibly work. I like to keep things simple and the couple things I got to sort-of work were noticeably slower (~20%).
This fix is slightly faster too by about 10% on average. Maybe because I'm not pulling every field in the model now? Anyway, wish I could use those helpers in the template, but i can live with this, especially since it allows me to move on...
I'd love to hear any other opinions. Thanks.
Related
Using jQuery and Javascript, I am building a chatbox from an array of messages. My current setup is something similar to this:
HTML:
<div id="messageTemplate">
<div class="messageContainer">
<div class="chatMessage"></div>
<div class="chatTime"></div>
<div class="chatActions">
<span class="chatAction deleteMessage">Delete</span>
</div>
</div>
</div>
Javascript:
var template=$('#messageTemplate');
var chatbox=$('#chatbox');
$.each(messageArr,function(index,messageObject) {
var newMessage=$(template.html()); //Make a new DOM
newMessage.find('div.chatMessage').text(messageObject.message);
newMessage.find('div.chatTime').text(messageObject.time);
newMessage.find('div.chatAction.deleteMessage').click(function() {
//Delete message Code
});
//Append newMessage to chatbox
newMessage.appendTo(chatbox);
});
This code works, but after reading this article I found out this is not efficient at all. With 100+ chat messages this starts to slow down.
What's the best way to be doing this? Not looking for code to be written for me, but just a general guide on the best method to template, build the html, append, and add click handlers?
So this is actually a very tricky concept to portray so here is my attempt.
I am utilizing an HTML form template in LANDesk Service Desk - tool is irrelevant but important to note that there is back-end code that I cannot touch that is generating HTML.
So basically, the tool is pulling data from a back-end database containing a list of objects. It then inputs this data into an HTML form template that I have created using variables as placeholders for the objects. The HTML is then built on the fly with however many objects are in the database. Thus, I have no way of accessing the head - (which means native JS, and inline CSS).
My template looks like this...
<div class="my-template">
<a class="my-template my-link">My Link</a>
</div>
<script>
var myLinks = document.getElementsByClassName('my-link');
for (var i = 0 ; i < myLinks.length ; i++) {
myLinks[i].style.display = "none";
}
</script>
When I view the source on the loaded page it looks something like this...
<body>
<!--misc. page stuff-->
<!--First Item-->
<div class="auto-create">
<div class="my-template">
<a class="my-template my-link">My-Link</a>
</div>
</div>
<!--Second Item-->
<div class="auto-create">
<div class="my-template">
<a class="my-template my-link">My-Link</a>
</div>
</div>
</body>
All of the elements are formatted the way I want them to be...besides the last element on each page. I have determined that this is because each time the tool is running the object through the template, it is running the script. The issue is, there is a stupid default button that they place at the bottom of each object that is broken. (This is why I have the script changing the style to display: none..should have mentioned this earlier). Basically I want to delay the execution of the script until not only the object has been run through the template...but the entire page has loaded...but I can't seem to get the last button to go away.
I know that this is a lot of poorly written words trying to form an explanation, but I really think this is impossible...but I am convinced there has to be a way. (Also, the company isn't providing us with any help in finding a workaround, so I had to basically MacGyver this one
I am really not great at web stuff, so I am apologizing in advance for a potentially poor explanation of my problem.
Basically, I have a webpage which utilizes the handlebars js templating. Unfortunately, this means that many of my div elements are contained within javascript tags like the following:
<script type="text/x-handlebars" data-template-name="index">
<div class="row intro">
......
</div>
<div class="descript">
.....
</div>
</script>
My intent is to grab one of these div elements using jquery.find(), but from what I understand, the html within the script tags is not treated as part of the dom...so jquery does not see it as a dom element. I was wondering if there is any other way I could go about this. Some more code is included.
Here is another more explicit explanation in case the one I gave above was a little muddled: I am working on a personal website and would like to embed a project I have been working on in unity3d, but I need to add/remove elements based on whether or not the client has the unity3d web player installed. Normally I would get a particular element with
var $missingScreen = jQuery("#unityPlayer").find(".missing");
where 'missing' is simply an element inside unityPlayer which displays a link if the client does not have unity3d. I am also using some javascript templating to make my site look pretty and as a result, I have this problem:
<script type="text/x-handlebars" data-template-name="index">
<div class="row intro">
<div class="intro-text">Hi, I'm *****</div>
</div>
<div class="descript">
<p>
Here's a Project I have been working on in case I am of interest to you:
</p>
</div>
<div class="content">
<div id="unityPlayer">
<div class="missing">
<a href="http://unity3d.com/webplayer/" title="Unity Web Player. Install now!">
<img alt="Unity Web Player. Install now!" src="http://webplayer.unity3d.com/installation/getunity.png" width="193" height="63" />
</a>
</div>
</div>
</div>
<p class="footer">« created with Unity »</p>
</script>
Jquery cannot access the missing element. Is there any way to do this? Thanks for any help you can give me and sorry again for my inexperience.
EDIT* some people might want to know: here is how I determine whether or not to show the missing div. Another note; everything works fine if I remove the script tags...it is only when I put html within the script tags that it becomes inaccessible to jquery.
jQuery(function() {
var $missingScreen = jQuery("#unityPlayer").find(".missing");
$missingScreen.hide();
u.observeProgress(function (progress) {
switch(progress.pluginStatus) {
case "missing":
$missingScreen.find("a").click(function (e) {
e.stopPropagation();
e.preventDefault();
u.installPlugin();
return false;
});
$missingScreen.show();
break;
case "installed":
$missingScreen.remove();
break;
case "first":
break;
}
});
u.initPlugin(jQuery("#unityPlayer")[0], "temmp.unity3d");
});
Instead of
var $missingScreen = jQuery("#unityPlayer").find(".missing");
I would try out
var $missingScreen = jQuery("#unityPlayer").children(".missing");
or
var $missingScreen = jQuery("#unityPlayer .missing");
Don't forget the space between Player and .missing!
I hope it works.
I am using the LiquidSlider framework and in each tab there is lots of HTML. So I decided to put the HTML into separate .html files to make the main page index.html cleaner.
Here is my HTML:
..
<head>
.. <-- Import jquery, slider files, etc -->
<!-- Import HTML from other files into divs -->
<script>
$(function(){
$("#about-content").load("about.html");
$("#other-content").load("other.html");
$("#help-content").load("help.html");
$("#contact-content").load("contact.html");
});
</script>
</head>
<body>
<section id="navigation">
..
</section>
<div class="liquid-slider" id="main-slider">
<!-- About -->
<div>
<h2 class="title">about</h2>
<div id="about-content"></div>
</div>
<!-- Other -->
<div>
<h2 class="title">other</h2>
<div id="other-content"></div>
</div>
<!-- Help -->
<div>
<h2 class="title">help</h2>
<div id="help-content"></div>
</div>
<!-- Contact -->
<div>
<h2 class="title">contact</h2>
<div id="contact-content"></div>
</div>
</div>
<section id="footer">
..
</section>
</body>
..
So when the document is loaded, theoretically the HTML would be loaded in via the .load calls right? It seems to work fine, until it gets to the very last tab (contact), where it just fails to load any content..
Odd right? I tried moving the divs around to see if it was a problem with my html files, but the last element always fails to load. Then I tried adding another tab, and the last two fail to load. This leads me to believe there is an upper-limit to the number of .load calls, capped at 3?
Anyone have any ideas or see any obvious problems? Or even suggest any better ways of achieving the same thing?
Thanks.
RTM, there's nothing there about a max number of calls, but there's a lot of information (and examples) of what kinds of callbacks you can use, which might just help you to diagnose the problem itself, for example:
$("#contact-content").load("contact.html", function( response, status, xhr )
{
if ( status == "error" )
{
var msg = "Sorry but there was an error: ";
console.log(xhr);//<-- check this
$( "#error" ).html( msg + xhr.status + " " + xhr.statusText );
}
});
As an alternative, just go for the old-school $.get call, since you don't seem to be passing any data to the server:
$.get( "contact.html", function( data )
{
$("#contact-content").html(data);
});
Another thing to consider might be: given that you're using liquidSlider, I take it not all of the content is visible from the off. Why not register a click handler, that .load's that content when the user actually clicks something? That does away with that series of load calls... Perhaps it's a concurrency issue of sorts. By that I mean: browsers restrict the number of concurrent AJAX requests that can be made.Perhaps you're running into that restriction, and have to wait for the requests to be completed? It's a long shot, but you never know... If you want to, check your browser here
But either way, using JS to fetch parts of the content dynamically is all well and good, but remember that I can switch off JS support in my browser. Or that, if your JS contains a syntax error, the script execution grinds to a halt, leaving me with a (half) empty page to gaze at.
Just using any server-side scripting language seems to me to be a better fit:
//index.php -- using PHP as an example
<div id="contact-content"><?php include 'contact.html'; ?></div>
After this gets processed by PHP, the response from the server will be a fully-fledged html page, that doesn't require any JS-on-the-fly loading. It'll almost certainly perform better, and still allows for cleaner html code on your server...
Server Side Includes would seem to me to be a better way of achieving the same thing. Use the right tool for the right job and all that.
<script>
var array = ['about', 'other', 'contact', 'help'];
for (i in array)
{
$('#'+array[i]).load(array[i]+'.html', function(){ });
}
</script>
just having some issues with this jQuery thing.
What i'm trying to do is:
i have some audio control buttons that look like this:
<p>Play audio</p>
but there are too many on the page so i'm trying to optimise the code and make a little function that checks for the div id on the button and adds tells the player what track to play.
so i've done this:
<div id="audioControlButtons-1">
<div class="speaker"> </div>
<div class="play"> </div>
<div class="pause"> </div>
</div>
<script>
$(document).ready(function() {
$("[id^=audioControlButtons-] div.play").click(function() {
var id = new Number;
id = $(this).parent().attr('id').replace(/audioControlButtons-/, '');
//alert(id);
player1.loadAudio(id);
return false;
});
});
</script>
my problem is:
the id is not passing to the the player1.loadAudio(id)
if i hardcode player1.loadAudio(1)
it works! but the moment i try to pass the variable to the function it doesn't work...
however if you uncomment the alert(id) thing you will see the id is getting generated...
can someone help?
cheers,
dan
I think I see your problem. The variable id is a string. Try;
player1.loadAudio(parseInt(id));
Yah and the initialise line isn't necessary. Just use;
var id = $(this).parent().attr('id').replace(/audioControlButtons-/, '');
I'm actually kind of confused with your example because you originally have this:
<p>Play audio</p>
but then you don't reference it again. Do you mean that this html:
<div id="audioControlButtons-1">
<div class="speaker"> </div>
<div class="play"> </div>
<div class="pause"> </div>
</div>
Is what you are actually creating? If so, then you can rewrite it like this:
<div class="audio-player">
<div class="speaker"> </div>
<div class="play" data-track="1"> </div>
<div class="pause"> </div>
</div>
Then in your script block:
<script>
$(document).ready(function() {
$(".audio-player > .play").click(function() {
var track = $(this).data('track');
player1.loadAudio(+track);
return false;
});
});
</script>
So a few things are going on here.
I just gave your containing div a class (.audio-player) so that it's much more generic and faster to parse. You don't want to do stuff like [id^=audioControlButtons-] because it is much slower for the javascript to traverse and parse the DOM like that. And if you are going to have multiples of the same element on the page, a class is much more suited for that over IDs.
I added the track number you want to the play button as a data attribute (data-track). Using a data attribute allows you to store arbitrary data on DOM elements you're interested on (ie. .play button here). Then this way, you don't need to this weird DOM traversal with a replace method just to get the track number. This saves on reducing unnecessary JS processing and DOM traversing.
With this in mind now, I use jQuery's .data() method on the current DOM element with "track" as the argument. This will then get the data-track attribute value.
With the new track number, I pass that along into your player1.loadAudio method with a + sign in front. This is a little javascript trick that allows you to convert your value into an actual number if that is what the method requires.
There are at least a couple of other optimizations you can do here - event delegation, not doing everything inside the ready event - but that is beyond the scope of this question. Hell, even my implementation could be a little bit optimized, but again, that would require a little bit more in depth explanation.