Ember: How to bind action to code generated with JS - binding

I have a simple view which renders set of images depending on given items array (simplified code), using this as I need to collect some other data to 'build' required class name(s):
App.MyView = Ember.View.extend({
buildTemplate: function () {
var itemz = this.get('items');
var classname = 'classNameDependingOnSomeCalculations...';
var out = '<div>';
$.each(itemz, function (index, obj) {
out += '<img {{action myActionHere}} src="' + obj.href + '" alt="" class="'+classname+'"/>';
});
out += '</div>';
return out;
}.property('view'),
defaultTemplate: Ember.Handlebars.compile(
"<div>{{{view.buildTemplate}}}</div>"
)
});
And in template I'm using it as
{{#each myObj in myCollection}}
{{view App.MyView itemsBinding="myObj.items" otherBinding="otherProps" }}
{{/view}}
Unfortunately this way Ember instead of binding the action puts {{action myActionHere}} directly into code...
How can I bind an action instead while building dynamic template?
I'm using Ember 1.1.2
P.S. Or maybe I should use quite other approach for building this view?

There is a workaround to make this work with the view as you've laid it out here... But this is really not the ember way of doing it. If for some reason you need this kind of an approach, I'll append an answer for that, but I'm going to aim to fix the underlying issue.
Instead of doing this as shown here, you should instead have code that looks like the following directly in your JSP:
{{#each myObj in myCollection}}
<div>
{{#each item in myObj.items}}
<img {{action myActionHere}} src={{item.href}} alt='' class={{classNameFunction}}/>
{{/each}}
</div>
{{/each}}
If your reason for wanting to do this as a view is so that you can reuse this functionality without rewriting the code, take a look at partials which are specifically designed for that purpose.

Related

passing backbone collection to view

I'm just starting out with backbone / grails and i've been struggling to figure out how to get everything to work.
I'm building a pricing configurator where a user selects a product type from radio group A and radio group B containing the quantity / pricing / discount data will do an ajax call to the backend for updated pricing data. I do not want to expose my pricing algorithm to the front end, so I was thinking I would use backbone to handle my ajax request / template.
I do not want to fully rely on js to create my UI, so on the initial page load, I'll build the gsp view with grails. Only problem I've noticed was my gsp view was being replaced by my handlebars template on initial page load. I guess this is fine, except it does two identical queries which isn't optimal.
Anyhow my code that does not seem to be working.
<script id="priceTemplate" type="text/x-handlebars-template">
<tr>
<td><input type="radio" value="" name="quantity">{{quantity}}</td>
<td class="price"><span>{{price}}</span></td>
<td class="discount"><span>{{discount}}</span></td>
</tr>
</script>
<asset:javascript src="bb_product/config.js"/>
<script>
var prices = new models.PriceList([],{productId:${productInstance.id}});
var priceView = new PriceView({collection: prices});
prices.fetch();
</script>
Models
var models = {};
models.PriceModel = Backbone.Model.extend({
//Is the model automatically populated from the collections json response?
})
models.PriceList = Backbone.Collection.extend({
initialize: function(models, options) {
this.productId = options.productId;
},
model: models.PriceModel,
url: function() {
return '../product/pricing/' + this.productId + '.json'
}
});
View
var PriceView = Backbone.View.extend({
el: '#product-quantities',
template: Handlebars.compile($("#priceTemplate").html()),
initialize: function(){
this.render();
},
render: function() {
console.log('collection ' + this.collection.toJSON()) //comes back empty
this.$el.html( this.template(this.collection.toJSON()));
}
});
json returned from url
[{"id":1,"quantity":10,"price":"10","discount":"10"},{"id":2,"quantity":50,"price":"20","discount"
:"10"}]
To initially get this up and working, what am I missing to display all items in the json object?
I've also see this code around, not sure what it does this.listenTo(this.collection, 'reset', this.render);
The reason you don't see any items is that the items aren't actually in the collection until after the view is rendered. Look at these two lines of code:
var priceView = new PriceView({collection: prices});
prices.fetch();
The first line renders the view (since you're calling render from within initialize). However, at that time, the prices collection is empty. Then, the second line fetches the data from the server and loads it into the collection; but by that time, the view has been rendered.
That last line of code you posted is the key to fixing this:
this.listenTo(this.collection, 'reset', this.render);
Usually, you'll put this inside the initialize function in your view class. What this does is "listen" to the collection instance, and when the reset event occurs, it will call the this.render function. (Of course, the method this.listenTo can "listen" to other objects for other events; see more details in the Backbone documentation).
If you add that line to the view's initialize function, the view will re-render whenever a "reset" event happens on the collection.
HOWEVER, by default, the "reset" event happens when all the models in the collection are replaced with another set of models, and this doesn't happen by default when you call a collection's fetch method (instead, the collection will try to "smart-update"). To force a reset of the collection when using fetch, pass {reset: true} as a parameter:
prices.fetch({reset: true});

Binding lost (after click) in angular js small example

I have a very small application in Angular JS. It's placed inside a bigger rails application, but I don't see too much interaction. The angular application, allows the user to interact with a group of categories. As easy as:
var angular_app = angular.module('angular_app', []);
angular_app.config(['$httpProvider', function($httpProvider, $cookieStore) {
//Protection
}]);
angular_app.controller('CategoriesController', function ($scope, $http) {
$scope.isEditing = false;
$scope.categoryName = '';
$http.get('/api/categories').success(function(data) {
//We use this to data-bind with the HTML placed below
$scope.categories = data;
});
$scope.addNewCategory = function() {
...
}
$scope.editCategory = function(index) {
if (!index)
return;
var selectedCategory = $scope.categories[index];
// With ng-show, we make visible the part of the UI
// that should be used for editing
$scope.isEditing = true;
}
$scope.cancelEditCategory = function() {
$scope.isEditing = false;
}
$scope.deleteCategory = function(index) {
...
}
});
angular.element(document).ready(function() {
angular.bootstrap(document, ['angular_app']);
});
The idea is that the information is shown in a list, and we have an 'edit' button that allows the user to see other part of the UI that will let him perform changes.
<div ng-controller="CategoriesController">
<div ng-show='isEditing' class="popup_menu">
DIV FOR EDITING
</div>
<ul>
<li ng-repeat="category in categories">
<a href="#" ng-click='deleteCategory($index)'>[X]</a>
<a href="#" ng-click='editCategory($index)'>[E]</a>{{ category.name }}
</li>
</ul>
<input type="text" id="categoryTextBox" ng-model="categoryName"/>
<button id="submit" ng-click='addNewCategory()'>New category</button>
</div>
When I'm clicking the edit button, the corresponding part of the UI gets visible, but just after that, something happens, and the ul that should render the list, looses completely the binding, just showing something like:
[X] [E]{{ category.name }}
When it must be showing:
[X] [E]computer science
[X] [E]politics
[X] [E]news
(Which is what I have in the scope). It happens a few after the click (and works for a sec). No errors on the console, no interactions with other libraries (as far as I can see).
Thanks!
Turbolinks
I have no experience with Angular, but perhaps your problem could be to do with Turbolinks - this is a way of Rails loading the <body> tag of a page only - keeping the <head> intact.
Turbolinks is notorious for Javascript on Rails, as each time you reload your <body> without reloading the <head> part of your page, all your JS bindings are going to disappear. The solution to this, in normal JS, is to use JQuery / Javascript delegation, and delegate from the document object:
$(document).on("action", "delegated_object", function(){
...
});
Apologies if this does not work - it's a common issue for us, but as I have no experience with Angular, I don't know if it's going to help you or not.
It seems that I should have been more careful with the links:
<a href="#" ng-click='deleteCategory($index)'>[X]</a>
<a href="#" ng-click='editCategory($index)'>[E]</a>{{ category.name }}
Don't know exactly how this works, but seems that if the link has his href attribute, a GET request is made against 127.0.0.1, breaking in some way the angular code. If you put them like:
<a ng-click='deleteCategory($index)'>[X]</a>
<a ng-click='editCategory($index)'>[E]</a>{{ category.name }}
The problem will be solved. Thanks all for reading and helping!

Disable entire jqGrid

I have been looking for methods on how to disable a jqGrid and I found some:
Using BlockUI plugin: http://jquery.malsup.com/block/
Using jqGrid options: loadui and set it to 'block'
First option is a great solution (I have not tried yet) and it is clearer maybe but I want to avoid using plugins if I can whenever I can do it by setting object properties so I am trying the second option but it is not working for me, jqGrid continues enabled.
My jqgrid in my asp.net mvc 4 view:
<div id="jqGrid">
#Html.Partial("../Grids/_PartialGrid")
</div>
and _PartialGrid:
<table id="_compGrid" cellpadding="0" cellspacing="0">
</table>
<div id="_compPager" style="text-align: center;">
</div>
so in the view, in script section I perform below on document ready and depending on the status of a property in my model (I disable it if id>0, otherwise I enable it on page reload):
#section scripts
{
#Content.Script("/Grids/CompGrid.js", Url) // Content is a helper javascript loader (see end of this post)
}
<script type="text/javascript">
$(document).ready(function () {
showGrid();
var disableCompGrid = #Html.Raw(Json.Encode(Model.ItemCompViewModel));
setStatusCompGrid(disableCompGrid.id > 0);
}
</script>
CompGrid.js is:
function showGrid() {
$('#_compGrid').jqGrid({
caption: paramFromView.Caption,
colNames: ....
}
function setStatusCompGrid(disabled) {
$('#_compGrid').jqGrid({
loadui: 'block',
loadtext: 'Processing...'
});
}
In the code above, also I have tried to pass as parameter disabled to showGrid function and depending on if it is true or false to set a variable to 'block' or 'enable' respectively and then setting loadui property with this variable but it is not working.
Content.cshtml:
#using System.Web.Mvc;
#helper Script(string scriptName, UrlHelper url)
{
<script src="#url.Content(string.Format("~/Scripts/{0}", scriptName))" type="text/javascript"></script>
}
Any ideas?
It's important to understand that the call $('#_compGrid').jqGrid({...}); converts initial empty <table id="_compGrid"></table> element to relatively complex structure of dives and tables. So you can do such call only once. Such call creates and initialize the grid. In other words the function showGrid has bad name. The function can be called only once. The second call of it will test that the grid already exist and it will do nothing. If you need to change some parameters of existing grid you can use setGridParam method.
In the case you can use absolutely another solution to block the grid. After the call $('#_compGrid').jqGrid({...}); the DOM element of the initial table get some expandos - new property or method. For example $('#_compGrid')[0] will contains grid property which contains beginReq and endReq methods. So you can first create the grid (in the showGrid function) and include options loadui: 'block' and loadtext: 'Processing...' in the list of options which you use. Then if you need to block the grid later you can use
$('#_compGrid')[0].grid.beginReq();
and the code
$('#_compGrid')[0].grid.endReq();
to remove blocking. See the demo which demonstrates this. Alternatively you can show overlays created by jqGrid manually like I described in the answer. The code will be simple enough:
var gridId = "_compGrid"; // id of the grid
...
$("#lui_" + gridId).show();
$("#load_" + gridId).text("Processing...").show();
to show the overlay and
$("#lui_" + gridId).hide();
$("#load_" + gridId).hide();
to hide the overlay. See another demo which works exactly like the first one.
you don't need any plugin. Just add/remove css:
.disabled {
pointer-events: none;
//optional
opacity: 0.4;
}
DEMO

Rails 3: best way to preview image before upload

I need to preview an image prior to submitting a form.
I work with Rails 3 and needs something that is browser compatible.
Any ideas how I can achieve that?
So! :) The main idea is to use the FileReader Javascript Class, which is really handy for what you need to do.
You just have to listen to the "change" event on your file input and then call a method that will use the "readAsDataURL()" method of the FileReader class. Then you just have to fill the source of a "preview img tag" with the returned result of the method...
I've wrote you a simple jsFiddle that achieves what you want. You can see my code below:
<!-- HTML Code -->
<div class="upload-preview">
<img />
</div>
<input class="file" name="logo" type="file">
//JS File
$(document).ready(function(){
var preview = $(".upload-preview img");
$(".file").change(function(event){
var input = $(event.currentTarget);
var file = input[0].files[0];
var reader = new FileReader();
reader.onload = function(e){
image_base64 = e.target.result;
preview.attr("src", image_base64);
};
reader.readAsDataURL(file);
});
});
And in the Mozilla Documentation, you have another example (surely more robust). This solution should work with Safari (version 6.0+).
This is the only way I know to preview an image prior to submitting a form, but I think it is quite a common way. Of course it has nothing to do with Ruby On Rails as we only use Javascript here... It would be impossible to do it using Rails only as you would have to upload the image before rendering it. (As Rails is server side, I think you perfectly understand why. :) )
HTML:
<input type="file">
<div id="image_preview"></div>
JS (require jquery):
$(document).ready(function(){
$('input[type="file"]').change(function(){
var image = window.URL.createObjectURL(this.files[0]);
$("#image_preview").css("background-image", "url(" + image + ")");
});
});

ASP.NET MVC 3 - Add/Remove from Collection Before Posting

I have a model that contains a collection, such as this:
class MyModel
{
public List<MySubModel> SubModels { get; set; }
}
In the view, I want to dynamically add/remove from this list using Javascript before submitting. Right now I have this:
$("#new-submodel").click(function () {
var i = $("#submodels").children().size();
var html = '<div>\
<label for="SubModels[' + i + '].SomeProperty">SomeProperty</label>\
<input name="SubModels[' + i + '].SomeProperty" type="textbox" />\
</div>'
$("#submodels").append(html);
});
This works, but it's ugly. And, if I want to show those labels/textboxes for the existing items, there's no clean way to do that either (without duplicating).
I feel like I should be able to use Razor helpers or something to do this. Any ideas? Help me stay DRY.
You approach may lead to unexpected errors if you when you are removing or adding the divs. For example you have 4 items, you remove the first item, then $('#submodels').children().size() will return 3, but your last inserted div has the name attribute value set SubModels[3].SomeProperty which results in a conflict. And if your posted values contain SubModels[1] but not SubModels[0] the default model binder will fail to bind the list (it will bind it as null). I had to learn this the hard way...
To eliminate the aforementioned problem (and your's) I suggest you do something like this:
$("#addBtn").click(function() {
var html = '<div class="submodel">\
<label>SomeProperty</label>\
<input type="textbox" />\
</div>'; // you can convert this to a html helper!
$("#submodels").append(html);
refreshNames(); // trigger after html is inserted
});
$(refreshNames); // trigger on document ready, so the submodels generated by the server get inserted!
function refreshNames() {
$("#submodels").find(".submodel").each(function(i) {
$(this).find("label").attr('for', 'SubModels[' + i + '].SomeProperty');
$(this).find("label").attr('input', 'SubModels[' + i + '].SomeProperty');
});
}
Then your view (or even better an EditorTemplate for the SubModel type) can also generate code like:
<div class="submodel">
#Html.LabelFor(x => x.SomeProperty);
#Html.EditorFor(x => x.SomeProperty);
</div>
It would also be possible to convert the code generation to a html helper class, and use it in the EditorTemplate and in the JavaScript code
I would recommend you going through the following blog post.

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