WinJS binding to nested control - windows-8

I am trying to implement semantic zoom control in my application. Here is a fragment of one of my pages:
<div id="semanticZoomDiv" data-win-control="WinJS.UI.SemanticZoom">
<div id="zoomedInListView"
class="win-selectionstylefilled"
data-win-control="WinJS.UI.ListView"
data-win-bind="winControl.itemDataSource: groupedList.dataSource; winControl.groupDataSource: groupedList.groups.dataSource;"
data-win-options="{
itemTemplate: select('#mediumListIconTextTemplate'),
groupHeaderTemplate: select('#headerTemplate'),
selectionMode: 'none',
tapBehavior: 'none',
swipeBehavior: 'none'
}">
</div>
<div id="zoomedOutListView"
data-win-control="WinJS.UI.ListView"
data-win-bind="winControl.itemDataSource: groupedList.groups.dataSource;"
data-win-options="{
itemTemplate: select('#semanticZoomTemplate'),
selectionMode: 'none',
tapBehavior: 'invoke',
swipeBehavior: 'none'
}">
</div>
</div>
The problem is, that semanticZoomDiv is empty.
However, if I remove attribute
data-win-control="WinJS.UI.SemanticZoom"
from semanticZoomDiv two ListViews render and are correctly filled with data. It seems like WinJS has problems with binding data to nested controls? (ListView controls are inside SemanticZoom control - after removal of outer SemanticZoom control data binds correctly).
I managed to make semantic zoom work using binding to global namespace via data-win-options, but I want to provide data for my page through view model, hence my trials to use data-win-bind.

I believe this is an object scoping issue, but am not on Win8 at the moment to verify. If I'm right, you can expose groupedList from your JavaScript code similarly to this.
WinJS.Namespace.define("YourApp", {
groupedList: groupedList,
});
and then change your declarative binding to include the YourApp namespace. That way your data is not in the global namespace.
Alternatively, you can do the data binding in the .js file
zoomedInListView.winControl.itemDataSource = groupedList.dataSource;
zoomedInListView.winControl.groupDataSource = groupedList.groups.dataSource;
zoomedOutListView.winControl.itemDataSource = groupedList.groups.dataSource;

Related

Change element type at runtime

Is it possible to dynamically define the type of an element inside a custom components template at runtime?
I'd like to avoid duplication of the inner contents of the button and a element in the following example:
<template>
<button if.bind="!isLinkBtn">
<span class="btn-icon">${icon}</span>
<span class="btn-text">${contentText}</span>
</button>
<a if.bind="isLinkBtn">
<!--
The content is a 1:1 duplicate of the button above which should be prevented
somehow in order to keep the view DRY
-->
<span class="btn-icon">${icon}</span>
<span class="btn-text">${contentText}</span>
</a>
</template>
Is it possible to write something like this:
<template>
<!--
The type of element should be defined at runtime and can be a standard HTML "button"
or an anchor "a"
-->
<element type.bind="${isLinkBtn ? 'a' : 'button'}">
<span class="btn-icon">${icon}</span>
<span class="btn-text">${contentText}</span>
</element>
</template>
I'm aware of dynamic composition with <compose view="${widget.type}-view.html"></compose> but as far as I know, this won't allow me to create default HTML elements but only custom components, correct?
I've asked this question on the Aurelia Gitter where Erik Lieben suggested to use a #processContent(function) decorator, replace the content within the given function and return true to let Aurelia process it.
Unfortunately I don't know how to actually apply those instructions and am hoping for some alternative approaches here or some details about how to actually accomplish this.
Edit
I've created a corresponding feature request. Even though possible solutions have been provided, I'd love to see some simpler way to solve this ;)
When you want to reuse HTML snippets, use compose. Doing so does not create a new custom element. It simply includes the HTML at the location of each compose element. As such, the view-model for the included HTML is the same as for the element into which it is composed.
Take a look at this GistRun: https://gist.run/?id=36cf2435d39910ff709de05e5e1bedaf
custom-link.html
<template>
<button if.bind="!isLinkBtn">
<compose view="./custom-link-icon-and-text.html"></compose>
</button>
<a if.bind="isLinkBtn" href="#">
<compose view="./custom-link-icon-and-text.html"></compose>
</a>
</template>
custom-link.js
import {bindable} from 'aurelia-framework';
export class CustomLink {
#bindable() contentText;
#bindable() icon;
#bindable() isLinkBtn;
}
custom-link-icon-and-text.html
<template>
<span class="btn-icon">${icon}</span>
<span class="btn-text">${contentText}</span>
</template>
consumer.html
<template>
<require from="./custom-link"></require>
<custom-link content-text="Here is a button"></custom-link>
<custom-link is-link-btn.bind="true" content-text="Here is a link"></custom-link>
</template>
You may want to split these into separate elements, like <custom-button> and <custom-link> instead of controlling their presentation using an is-link-btn attribute. You can use the same technique to reuse common HTML parts and composition with decorators to reuse the common code.
See this GistRun: https://gist.run/?id=e9572ad27cb61f16c529fb9425107a10
Response to your "less verbose" comment
You can get it down to one file and avoid compose using the techniques in the above GistRun and the inlineView decorator:
See this GistRun: https://gist.run/?id=4e325771c63d752ef1712c6d949313ce
All you would need is this one file:
custom-links.js
import {bindable, inlineView} from 'aurelia-framework';
function customLinkElement() {
return function(target) {
bindable('contentText')(target);
bindable('icon')(target);
}
}
const tagTypes = {button: 'button', link: 'a'};
#inlineView(viewHtml(tagTypes.button))
#customLinkElement()
export class CustomButton {
}
#inlineView(viewHtml(tagTypes.link))
#customLinkElement()
export class CustomLink {
}
function viewHtml(tagType) {
let result = `
<template>
<${tagType}${tagType === tagTypes.link ? ' href="#"' : ''}>
<span class="btn-icon">\${icon}</span>
<span class="btn-text">\${contentText}</span>
</${tagType}>
</template>
`;
return result;
}
Sorry, I was doing 2 things at once while looking at gitter, which I am not good at apparently :-)
For the thing you wanted to accomplish in the end, could this also work?
I am not an a11y expert or have a lot of knowledge on that area, but from what I understand, this will accomplish what you want. The browser will look at the role attribute and handle it as a link or button and ignores the actual element type itself / won't care if it is button or anchor it will act as if it is of the type defined in role.
Then you can style it like a button or link tag with css.
<a role.bind="type"><span>x</span><span>y</span></a>
where type is either link or button, see this: https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/ARIA_Techniques/Using_the_link_role

How to specify two-way bindable property in HTML-only custom element (Aurelia)

I have created an HTML-only custom element to represent an input and all the DOM structure that does with it.
I have set up bindable properties on the template to supply values into the element. However, I don't see a way to specify that a bindable should be two-way.
the element:
<template bindable="label,name,placeholder,value">
<div class="form-group">
<label class="control-label col-sm-2" for.bind="name">${label}</label>
<div class="col-sm-7 col-md-6">
<input class="form-control" id.bind="name" placeholder.bind="placeholder" value.bind="value" />
</div>
</div>
</template>
I know I can specify two-way binding each time the element is used (e.g. <my-element value.bind="firstName & twoWay"></my-element>, but I want to set the default without having to create and maintain a separate class (i.e. I like html-only element for this case).
Is this possible?
I don't think that's possible in a simple way. I mean, you could figure out how to override the default behaviour somehow ([source], [source]), but it's likely that you would end up with several more classes to maintain.
Documentation is clear about that:
You can even have bindable properties on your HTML Only Custom Element. These properties default to one-way databinding, but you can't change the default, though you are still free to explicitly set the binding direction when you bind to the Custom Element.
In my opinion, using .two-way explicit binding is your simplest option here.
<my-element value.two-way="firstName"></my-element>

vue.js - Change text based on default/clicked class

Given the following:
<div id="#my-container">
<div class="title">Companies</div>
<div class="tab active tab-apple">Apple</div>
<div class="tab tab-google">Google</div>
</div>
When page is loaded without any tab clicks yet, whichever tab with the default active class, needs to go in the .title div. For the example above, <div class="title">Apple</div>
On click of a tab, the class is switched to active, and vue.js needs to update the .title div once again.
How can this be done with vue.js? I've tried but not able to get it to work as intended.
The answer by David is one way to do it. But Vuejs offers in-line computations for this. So, no need to hook into any CSS event. Here's some code to explain:
Create a data property active_tab, just like David mentioned. And then bind it's value just like he's done it. In your tabs, add an click event and at that event, assign appropriate value to active_tab.
<div class="tab active tab-apple" #click="active_tab = Apple">Apple</div>
<div class="tab tab-google" #click="active_tab = Google">Google</div>
Now, to dynamically assign the active class to the respective tab, make the class attribute, a computed property, like this:
<div
:class="['tab', active_tab == 'Apple' ? 'active' : '', 'tab-apple']"
>
Apple
</div>
What this code is basically doing is, :class makes class a computed property. Then the commas in the array divide the statement. So, the computation will always add tab and tab-apple classes. But, only if active_tab == 'Apple' then ? add 'active' else : add ''
Not sure which CSS framework you are using, but normally I hook into the events thrown by the tab switching (many CSS frameworks provide this access). Once hooked into it, you can write a Vue custom directive that will take that event and use it to update a VM attribute that indicates which tab is active.
Then you can use normal mustache templating to get it into your template:
<div class="title">{{ active_tab }}</div>

Durandal: Showing a 'LOADING...' during composition

I can easily show a loading message while the activate method is doing its thing like so:
<div data-bind="compose:ActiveVm">
<div class="text-center" style="margin : 75px">
<i class="fa fa-spinner fa-spin"></i>
</div>
</div>
However if I then update my ActiveVm property with a different viewmodel, the splash content does not show. I understand that the splash content is only designed to show on 'initial' load, but what options do I have for displaying such a message when transitioning from one viewmodel to another?
Note that this composition does not participate in routing...
Update: Related durandal issue here which might be of value to future visitors: https://github.com/BlueSpire/Durandal/issues/414
This begs for a comment of 'what have you tried?' but given that I could see the benefit of this for future users I wanted to throw in my $0.02 -
The splash displays on your screen until Durandal loads up the application and replaces the div with id="applicationHost" 's content with the shell view and the subsequent views that are loaded. If you wanted to make this a re-usable component one thing that you could do is to take that Html.Partial view that is being loaded and create your own view inside of your app folder in your Durandal project.
For example you would create a new HTML view inside of your app folder -
splashpage.html
<div class="splash">
<div class="message">
My app
</div>
<i class="icon-spinner icon-2x icon-spin active"></i>
</div>
And then compose it from your shell -
<div data-bind="if: showSplash">
<!-- ko compose: 'splashpage.html' -->
<!-- /ko -->
</div>
And in your view model you would toggle the observable showSplash whenever you want to show / hide it -
var showSplash = ko.observable(false);
var shell = {
showSplash: showSplash
};
return shell;
And you could call that from your activate methods inside your other view models like this -
define(['shell'], function (shell) {
function activate() {
shell.showSplash(true);
// do something
shell.showSplash(false);
}
});
This sounds to me like a scenario where a custom transition may be useful. When the composition mechanism switches nodes in and out of the DOM, it can use a transition.
This page, under Additional Settings>Transition (about halfway down) describes a custom transition: http://durandaljs.com/documentation/Using-Composition/

Two-Way binding in Windows 8 HTML / JavaScript Metro Apps

I'm trying to achieve a two way binding between an input field and a field in my JavaScript ViewModel. The binding has been wired up declarativly. Unfortunately the changes I do in the UI aren't reflected in my ViewModel.
My Code looks like that (written out of my head as I don't have the code here)
View:
<form data-win-bind="onsubmit: onCalculate">
<div class="field">
Product Name:
<input type ="number" data-win-bind="text:value1"/>
</div>
<div class="field">
Product Price:
<input type ="number" data-win-bind="text:value2"/>
</div>
<div class="field">
Result
<br />
<span data-win-bind="innerText: result" />
</div>
</form>
JavaScript
var model= WinJS.Class.define(
function() {
this.onCalculate = calculate.bind(this);
this.value1 = 0;
this.value2 = 0;
this.result = 0;
},{
value1: 0,
value2: 0,
result: 0
calculate: function() {
this.result = this.value1 + this.value2;
return false;
}
}, {});
// Make the model Observable
var viewModel = WinJS.Binding.as(new model());
WinJS.Binding.processAll(null, viewModel);
When I apply the binding, the ui shows my initial values. The form submition is correctly wired with the calculate function. The values of value1 and value2 however aren't updated with the users input.
What I'm trying to achive is to keep my JavaScript unaware of the underlying view. So I don't want to wire up change events for the html input fields in JavaScript.
Is there any way to achive this with pure WinJS? All samples I've found so far only do a one-way binding and use event listeners to update the ViewModel with changes from the UI.
WinJS only supports one-way binding for Win8. It is necessary to wire up listeners for change events in the UI elements, hence the nature of the samples you've seen. In other words, the implementation of WinJS.Binding's declarative processing doesn't define nor handle any kind of two-way syntax.
It would be possible, however, to extend WinJS yourself to provide such support. Since WinJS.Binding is just a namespace, you can add your own methods to it using WinJS.Namespace.define (repeated calls to this are additive). You could add a function like processAll which would also look for another data-* attribute of your own that specified the UI element and the applicable change events/properties. In processing of that you would wire up a generic event handler to do the binding. Since you have the WinJS sources (look under "References" in Visual Studio), you can see how WinJS.Binding.processAll is implemented as a model.
Then, of course, you'd have a great piece of code to share :)
This article provides a nice solution:
http://www.expressionblend.com/articles/2012/11/04/two-way-binding-in-winjs/