How can I make conditional binding in knockout.js? - binding

I tried this one :
<div data-bind="attr: {class: itemSelected? 'selected' : 'unselected' }"></div>
But it does not work :)

Assuming you have this:
function viewModel() {
this.itemSelected = ko.observable(true);
}
ko.applyBindings(new viewModel());​
Add a () after itemSelected to get the current value of the observable that you can use with the ternary operator:
<div data-bind="attr: { class: itemSelected() ? 'selected' : 'unselected' }"></div>​
http://jsfiddle.net/RK7Ty/
If you didn't need to assign the unselected class for the non selected state you could do this instead:
<div data-bind="css: { selected: itemSelected }"></div>​
http://jsfiddle.net/RK7Ty/1/

Following worked for me, i was using both css and id attributes, for me it did't work if css attribute is not the first one , so keep css attribute as your fist one.
<div class="panel-collapse collapse" data-bind="css:{in:$index()==0}, attr: { id:'collapse'+$index()} ">
...
...
...
</div>

Related

How do I to change the style of a tag using Razor?

I have a HTML tag which I want to only be visible when a condition is true, otherwise it will be hidden. To do this, I'm trying to change the style attribute using Razor, but still can't do this.
Note that: I don't want to use JQuery, I want to use only Razor.
How could I do this ?
Trying
<!--it will only visible if the conditional true-->
<div class="form-group" #(usuario.role == RoleType.Investidor) ? style="display:none;" : style="display:normal;">
<h1>Description</h1>
</div>
I would assume something like this works:
<div class="form-group" style="#(usuario.role == RoleType.Investidor ? "display: none" : string.Empty)">
<h1>Description</h1>
</div>
Move the ternary statement inside the attribute value for style. You may also be able to replace string.Empty with null - depending on context, that might enable the Razor engine to omit the attribute, rather than rendering an empty value.
You could try to do something like that:
#if (usuario.role != RoleType.Investidor)
{
<div class="form-group" style="display: normal">
<h1>Description</h1>
</div>
}
If RoleType equals Investidor, the div will not be shown at all.
If presence of this element is important to you, you can leave it like that:
#if (usuario.role != RoleType.Investidor)
{
<div class="form-group" style="display: normal">
<h1>Description</h1>
</div>
} else {
<div class="form-group" style="display: none">
<h1>Description</h1>
</div>
}

Dynamic checkbox control group using jquery mobile and knockout

I'm trying to dynamically create and filter a jquery mobile control group containing checkboxes using knockout binding. The basic idea is that the user selects an option which filters the list of checkboxes in the control group. I've seen similar questions on here but they all seem to be a one-time binding where once bound by ko and enhanced by jqm they remain unchanged. I have that behavior working, the issue occurs when the underlying viewModel changes and ko updates the list of checkboxes in the control group. A full demo of the behavior can be found on jsfiddle here: http://jsfiddle.net/hkrauss2/JAvLk/15/
I can see that the issue is due to jqm creating a wrapper div when enhancing the control group. Ko then puts new elements above the wrapper div when updating the DOM. Basically I'm asking if anyone has solved this issue and also if anyone thinks I'm asking for trouble by integrating these two libraries? Thanks to everyone in advance.
Here is the Html:
<div id="home" data-role="page">
<div data-role="header">
<h2>Knockout Test</h2>
</div>
<div data-role="content">
<ul id="parent-view" data-role="listview" data-inset="true" data-bind="foreach: parentCategories">
<li></li>
</ul>
<p>
To reproduce the issue select Restaurants, come back and select Nightlife or Bars
</p>
</div>
</div>
<div id="list" data-role="page">
<div data-role="header">
<h2>Knockout Test</h2>
<a data-rel="back" data-icon="carat-l" data-iconpos="notext">Back</a>
</div>
<div data-role="content">
<form>
<div id="child-view" data-role="controlgroup" data-bind="foreach: childCategories, jqmRefreshControlGroup: childCategories">
<input type="checkbox" name="checkbox-v-2a" data-bind="attr: {id: 'categoryId' + id}" />
<label data-bind="text: description, attr: {for: 'categoryId' + id}" />
</div>
</form>
</div>
</div>
And the basic javascript. Note there are two external js files not listed here. One sets $.mobile.autoInitializePage = false; on the mobileinit event. The other brings in data in the form of a JSON array which is used to initialize the Categories property in the AppViewModel.
// Custom binding to handle jqm refresh
ko.bindingHandlers.jqmRefreshControlGroup = {
update: function (element, valueAccessor) {
ko.utils.unwrapObservable(valueAccessor());
try {
$(element).controlgroup("refresh");
} catch (ex) { }
}
}
function GetView(name) {
return $(name).get(0);
}
// Define the AppViewModel
var AppViewModel = function () {
var self = this;
self.currentParentId = ko.observable(0);
self.Categories = ko.observableArray(Categories); // Categories comes from sampledata.js
self.parentCategories = ko.computed(function () {
return ko.utils.arrayFilter(self.Categories(), function (item) {
return item.parentId == 0;
});
});
self.childCategories = ko.computed(function () {
return ko.utils.arrayFilter(self.Categories(), function (item) {
return item.parentId == self.currentParentId();
});
});
self.OnClick = function (viewModel, $event) {
self.currentParentId(viewModel.id);
return true;
};
};
// Create the AppViewModel
var viewModel = new AppViewModel();
// Apply bindings and initialize jqm
$(function () {
ko.applyBindings(viewModel, GetView('#parent-view'));
ko.applyBindings(viewModel, GetView('#child-view'));
$.mobile.initializePage();
});
Update
My old solution wraps each element in a ui-controlgroup-controls div, which adds unnecessary markup. However, the enhancement part is essential.
$(element).enhanceWithin().controlgroup("refresh"); /* line 16 in fiddle */
The new solution is more dynamic to maintain clean markup with no additional wrappers:
First step: Once controlgroup is created controlgroupcreate (event), add data-bind to its' container .controlgroup("container")
Second step: Add checkbox consisted of input and label. At the same time, for each element, add data-bind
Third step: Apply bindings ko.applyBindings().
The static structure of the controlgroup should be basic, it shouldn't contain any elements statically. If a checkbox is added statically, each dynamically created checkbox will be wrapped in an additional .ui-checkbox div.
<div id="child-view" data-role="controlgroup">
<!-- nothing here -->
</div>
JS
$(document).on("controlgroupcreate", "#child-view", function (e) {
$(this)
.controlgroup("container")
.attr("data-bind", "foreach: childCategories, jqmRefreshControlGroup: childCategories")
.append($('<input type="checkbox" name="checkbox" />')
.attr("data-bind", "attr: {id: 'categoryId' + id}"))
.append($('<label />')
.attr("data-bind", "text: description, attr: {for: 'categoryId' + id}"));
ko.applyBindings(viewModel, GetView('#child-view'));
});
Demo
Old solution
As of of jQuery Mobile 1.4, items should be appended to .controlgroup("container") not directly to $("[data-role=controlgroup]").
First, you need to wrap inner elements of controlgroup in div with class ui-controlgroup-controls which acts as controlgroup container.
<div id="child-view" data-role="controlgroup" data-bind="foreach: childCategories, jqmRefreshControlGroup: childCategories">
<div class="ui-controlgroup-controls">
<input type="checkbox" name="checkbox-v-2a" data-bind="attr: {id: 'categoryId' + id}" />
<label data-bind="text: description, attr: {for: 'categoryId' + id}" />
</div>
</div>
Second step, you need to enhance elements inserted into controlgroup container, using .enhanceWithin().
$(element).enhanceWithin().controlgroup("refresh"); /* line 16 in fiddle */
Demo
Omar's answer above works very well. As he mentions in the comments however it does wrap each input/label combination in their own div. This doesn't seem to affect anything visually or functionally but there is another way as outlined below. Basically it uses the containerless control flow syntax to bind the list.
New Html
<div id="child-view" data-role="controlgroup">
<!-- ko foreach: childCategories, jqmRefreshControlGroup: childCategories, forElement: '#child-view' -->
<input type="checkbox" name="checkbox-v-2a" data-bind="attr: {id: 'categoryId' + id}"></input>
<label data-bind="text: description, attr: {for: 'categoryId' + id}"></label>
<!-- /ko -->
</div>
Using the containerless syntax means that we lose the reference to the controlgroup div in the custom binding handler. To help get that back I added the id as '#child-view' in a custom binding named forElement. The magic still all happens in the custom binding handler and Omar's enhanceWithin suggestion remains the secret ingredient. Note: I needed to change the argument list to include all arguments passed by ko.
ko.bindingHandlers.jqmRefreshControlGroup = {
update: function (element, valueAccessor, allBindings, viewModel, bindingContext) {
ko.utils.unwrapObservable(valueAccessor());
try {
$(allBindings.get('forElement')).enhanceWithin().controlgroup("refresh");
} catch (ex) { }
}
}
Final note: To use a custom handler on a virtual element ko needs to be notified that it is ok. The following is the updated start up statements:
// Apply bindings and initialize jqm
$(function () {
ko.virtualElements.allowedBindings.jqmRefreshControlGroup = true; // This line added
ko.applyBindings(viewModel, GetView('#parent-view'));
ko.applyBindings(viewModel, GetView('#child-view'));
$.mobile.initializePage();
});

Expressions are not evaluated in $watch of custom directive of angularjs

I have a below custom directive in angularjs which uses model thats gets updated from server,
I have added a watch listener to watch the changes of that model,
var linkFn;
linkFn = function(scope, element, attrs) {
scope.$watch('$parent.photogallery', function(newValue, oldValue) {
if(angular.isUndefined(newValue)) {
return;
}
var $container = element;
alert($container.element);
$container.imagesLoaded(function() {
$container.masonry({
itemSelector : '.box'
});
});
});
};
return {
templateUrl:'templates/Photos_Masonry.htm',
replace: false,
transclude:true,
scope: {
photogallery: '=photoGallery',
},
restrict: 'A',
link: linkFn
However, when i debug in my watch directive, i still see that expressions in templates are still unresolved.i.e. photo.label, ng-src all are still unresolved. AFIK, $digest would be called only after $eval. Is this intended behavior?
My jQuery calls are not working due to this? Is there any other event where i get the result element with evaluated expressions?
Here is my template, which has ng-repeat in it,
<div id="container" class="clearfix">
<div class="box col2" ng-repeat="photo in photogallery">
<a ng-href="#/viewphotos?id={{photo.uniqueid}}&&galleryid={{galleryid}}"
title="{{photo.label}}"><img
ng-src="{{photo.thumbnail_url}}" alt="Stanley" class="fade_spot" /></a>
<h3>
<span style="border-bottom: 1px solid black;font-weight:normal;font-size:14px;">{{galleryname}}</span>
</h3>
<h3>
<span style="color:#20ACB8;font-weight:normal;font-size:17px;">{{photo.seasonname}}</span>
</h3>
</div>
</div>
photogallery is initialized in parent controller,
function MyCtrlCampaign($scope, srvgallery, mygallery) {
$scope.updatedata = function() {
$scope.photogallery = srvgallery.getphotos($routeParams);
};
$scope.getphotos = function() {
srvgallery.photos().success(function(data) {
$scope.updatedata();
}).error(function(data) {
});
};
Directive is used in below way,
<div masonry photo-gallery="photogallery" >
</div>
Kindly let me know your views on this.
Looks like this has been resolved in your Github issue (posted for the convenience of others).

Change position of input filed for jQuery Mobile Filter List

Im using the jQuery Mobile Filter List:
http://jquerymobile.com/test/docs/lists/lists-search-with-dividers.html
Is it possible to move the position of the input field so I can put it into a div already on my page?
Using jQuery's appendTo seems to work fine but its kind of a hacky solution. Thanks
this is what I found while searching for solution to a similar problem.
HTML code example:
<div data-role="page" id="page-id">
<div data-role="content">
<div data-role="fieldcontain">
<input type="search" name="password" id="search" value="" />
</div>
<div class="filter-div" data-filter="one">1</div>
<div class="filter-div" data-filter="two">2</div>
<div class="filter-div" data-filter="three">3</div>
<div class="filter-div" data-filter="four">4</div>
<div class="filter-div" data-filter="five">5</div>
</div>
</div>
JS code example:
$(document).delegate('#page-id', 'pageinit', function () {
var $filterDivs = $('.filter-div');
$('#search').bind('keyup change', function () {
if (this.value == '') {
$filterDivs.slideDown(500);
} else {
var regxp = new RegExp(this.value),
$show = $filterDivs.filter(function () {
return ($(this).attr('data-filter').search(regxp) > -1);
});
$filterDivs.not($show).slideUp(500);
$show.slideDown(500);
}
});
});
This way you can place your input text box anywhere on your page and it should properly filter a list of items you want.
JSFiddle DEMO: http://jsfiddle.net/cZW5r/30/

How to get the value of the element selected in ListView JQUERYMOBILE

Hi i'm developping a simple listView that lists the column "firstname" of my table : i want to get the selected value (name) , i found this link but it shows he how to get the index and not the value of the selected item http://jsfiddle.net/w2JZU/
here's my code :
HTML:
<div id="popup-bg">
</div>
<div id="popup-box">
<div data-role="page" id="home">
<div data-role="header">
<h1>Players</h1>
</div>
<div data-role="content">
<ul data-role="listview" id="artiste" >
</ul>
</div>
</div>
</div>
</section>
js :
function successCB()
{
db.transaction(queryDB, errorCB);
}
function queryDB(tx)
{
tx.executeSql('SELECT * FROM Players ', [], querySuccess, errorCB);
}
function querySuccess(tx, results)
{
var len = results.rows.length;
var dataset= results.rows;
$("#artiste").empty();
for (var i = 0; i < len; i++)
{ item = dataset.item(i);
$("#artiste").append( "<li data-theme='c'><a href='game.html'>
<img src='images/avatar.jpg'><h3>"+item['firstName']+"</h3></a></li>" );
}
There isn't a "value" for an item in a list using the li tag. However, you can get the text of what's in that list element using the jQuery .text() method. I've modified the jsfiddle you referenced to do exactly that: http://jsfiddle.net/Cht2e/
You might want to consider adding another attribute to the li tag, such as data-name (you can make up the attribute) and then you can get that via the jQuery .attr() method. For example, you might change you append code to do:
$("#artiste").append( "<li data-theme='c' data-name='"+item['firstName']+"'><a href='game.html'>
<img src='images/avatar.jpg'><h3>"+item['firstName']+"</h3></a></li>" );
And then attach your click handler like this:
$('#artiste').children('li').on('click', function () {
alert('Selected Name=' + $(this).attr('data-name'));
});
I don't think this is necessarily the best structure or approach to take, but it will accomplish what you're asking.

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