Is there a way by which I can duplicate or clone dijit widgets?
Basically, idea is to improve page rendering performance by minimizing widget creation time.
We have a single page web application and we do not reload the entire page whenever the user performs any action.
The flow of events is as follows,
The main page is loaded by the browser. It contains a dijit ContentPane which acts as a master container and displays the entire page using various other dijit widgets like textboxes, tabs, datefield, Enhanced grid etc.
The user performs an action (e.g. click on a dijit button)
The application sends an ajax call to server which processes the button click event and generates UI of the next page.
Browser receives successful response from ajax call and calls refresh method of dijit ContentPane. Which triggers destruction of existing widgets and new set of widgets are created and placed at appropriate position. (instead of refreshing the entire page)
The user again performs some action and again the refresh method is called which triggers destruction of existing widgets and new set of widgets are created and placed at appropriate position.
Because of such architecture the browser has to destroy existing widgets and recreate them again and again. Which results in slow performance.
The idea is to have a set of widgets always readily available on the browser clone them and place at appropriate position and update them instead of recreating each time.
Yes this is possible with something called _AttachMixin.
Basically there is no getting around the fact that your widgets would need to attach event listeners to the HTML Document. What can be cut out though is the time in the Dijit Widget's lifecycle to generate the DOM. As we well know, simple Dijit widgets like a dijit/form/Button has a div inside a div inside a div etc.
This is explained in detail here http://dojotoolkit.org/reference-guide/1.9/dijit/_AttachMixin.html
Here is an example using Node.JS as a backend. http://jamesthom.as/blog/2013/01/15/server-side-dijit
This is a tough problem and this concept isn't explained very thoroughly. If you have a backend that is not Node.JS you have to manually make the widget string and pass it as a response to your AJAX and an follow the example from the 1st link (Ref Doc)
We have had lots of widgets of our app render nicely within the client side. A far less complicated approach would be to simply show / hide (instead of render and destroy) widgets as and when they are needed. I assume that you app's access policy would focus on data and not which person has access to which widget.
Related
Wondering the best way to prevent a GTM tag from firing. I found https://rbardini.com/automating-gtm-data-layer-tests/ which tags about fetching the dataLayer variable and comparing it in an assertion, but this looks like a clumsy approach when you want to write to the dataLayer on every page.
For example, it suggests:
const getDataLayer = ClientFunction(() => window.dataLayer)
We use Google Tag Manager to automatically load tags on our website. Unfortunately one of them is CloudIQ (from PayPal) which pops up an iframe overlay offering a newsletter signup or ability to save your shopping basket. The Trigger in our GTM setup for that tag is simply 'All Pages'. When it pops up it generally blocks our test because Selectors cannot be clicked.
Our page flow is over several pages of an online shop, e.g.:
visit home page, click a product - navigates to a product page
click some options on the product page, then add to cart
go through checkout flow
So there might be many pages visited due to click actions.
There is an ability in GTM to define Variables and then use them in Exceptions for a tag, so I could prevent the CloudIQ tag firing either via a/ a global variable or b/ a dataLayer variable. However, I can't see how to elegantly get these set for each page visited during my test, such that they would exist when the GTM examines variables in order to block a Tag from being loaded. Fixture.beforeEach isn't right because it would only run once per fixture, and any data it set on the page's scope would be lost as soon as a page navigation occurs.
Anyone got experience of this sort of thing?
(The alternative of course is to detect the overlay, use switchToIframe to switch into the CloudIQ iframe and close it manually, but it pops up quite erratically and I'd prefer to simply disable the Tag altogether during tests as it's not core functionality of our website that we need to test.)
One way would be to set a custom user agent string to your test suite, create a custom javascript variable that returns the value for navigator.useragent, and make an exception trigger that blocks the tag.
Or any variation on that theme - set a cookie, use a url parameter, or if you test suite allow inject a global js variable, and check for the value in an exception trigger.
There is no need to avoid firing of events on the client side. Just mock the service routes for Google Tag Manager and CloudIQ and imitate correct responses for them.
I'm converting my site from using jQueryUI to jQuery Mobile, and I'm having some trouble.
I have a page that lets users add new timesheet entries. They click the "Add" button and it retrieves a Partial View from the server right onto the page.
The problem is that jQuery Mobile is not applying to any of the elements in the Partial View.
How can I force jQuery Mobile to process my elements after they've been inserted into the page?
The short answer is that you can just trigger the create method on the parent element of where you inserting your partial view.
For example $('#container').trigger( "create" );
Alternatively most widgets can be manually initialized by calling them on the element, for example for a listview: $('#myListview').listview(). This can be useful if you have only a few elements that need to be enhaced and you don't want to traverse all the child elements of the container. You should also know that for many widgets there is also a refresh method which you can call if you add elements to it after it has already been initialized for example $('#myListview').listview('refresh).
Also have a look at the following Q & A from the JQM docs which deals with this issue and for an explanation as to why it is necessary to call these methods.
Question: Content injected into a page is not enhanced.
Answer:
jQuery Mobile has no way to know when you have injected content into a
page. To let jQuery Mobile know you have injected content that must be
enhanced, you need to either make sure the plugins are called to
enhance the new elements or trigger("create") on the parent container
so you don't have to call each plugin manually.
in a ASP.NET MVC application that I am currently working there are multiple places in a single page that the user can click. So there is a main menu that's in _layout and for each inidividual page there can be links associated with that page.
I am trying to use a loader which will be shown on every click, mainly where the response takes time but for now it's for every click.
For example in the home page, from the main menu the user can click Students and the loader should come up and hide when the page loads completely. On the students page there can be an ajax call that gets data and binds it to the grid.
So from the time the user clicks on a menu link and the page loads the loader is active/shown. It's hidden once the page loads completely.
The grid can have editing functionality and when the user clicks on any of the CRUD links the loader should show and hide.
I am looking at suggestions on implementing this requirement.
If I can hookup any of the MVC events, that would be cool as I want less of Javascript/jQuery stuff but if Javascript/jQuery is the way then that's fine too.
Currently I don't have anything so anypointers are appreciated.
Assuming AJAX is being used
I don't see a way to keep this server-side without a middle page with a redirect being used (which would just be unnecessary bloat). And, since you're not opposed, you can implement this fairly easily using jQuery and something like blockUI.
I'll let you play with refining the binding to only links you care about, but for now we'll assume all links. Also, MVC should be using jQuery for things like Ajax.Actionlink so we can hijack events like $.ajaxStart and $.ajaxStop:
function showLoadingScreen(enabled){
return enabled ? $.blockUI() : $.unblockUI();
}
$(document).ajaxStart(function(){
showLoadingScreen(true);
}).ajaxStop(function(){
showLoadingScreen(false);
});
Later on you can maybe apply classes to the links you care about and just bind to them (instead of $.ajaxStart) but I'll leave that up to you.
I have a question to creator of WinRT XAML Toolkit that had helped me a lot.
What is the best mechanism for working with rich pages in WinRT?
These are the conditions:
There are about 2 pages that have a lot of elements and some high resolution images in the background. Obviously they consume time to load their content. That's why I use AlternativeFrame.Preload() method from the Toolkit.
Also these pages are the most frequently used.
That's why I stand before choosing to either constantly preload these pages (create, draw, fill) but when it is needed or creating my own page cache that would store them (maybe I am blind and the Toolkit already has this functionality?).
Can you advise what's the best practice in this problem and whether maybe there's a third way?
To add some more background - the WinRT XAML Toolkit library has two controls: AlternativeFrame and AlternativePage that are alternate implementations of the base Frame and Page classes that come out of the box in Windows 8 SDK for dealing with UI navigation - similar to how you navigate pages in a web browser. The API of these alternative controls is almost the same as in the base ones, but it adds some more support for asynchronous development model, page transition animations and preloading pages before they are requested.
Currently the Preload() method preloads a page of a given type in the background and puts it in a cache and when a Navigate() method is invoked to navigate to the page of that type - instead of instantiating a new page - the one in the cache is used, so it can immediately be shown, but also - the cache gets emptied and the next time you want to navigate to that same page - you need to preload it again. This works well if you don't return to the preloaded page often and the page uses a lot of memory, but if you want to keep that page in cache - there is not built-in support for that. The original Page class has a NavigationCacheMode property that allows to configure a page to be kept in cache once it is loaded the first time and it would be a good option for you, but AlternativePage doesn't have that support yet. I am thinking about adding it there today since I have some free time, so you might decide to wait for me to do it. Other options include
displaying your page on top of the navigation frame instead of navigating to it in the frame - then you could simply show/hide it when needed
or you can switch back to the standard Frame/Page controls and set NavigationCacheMode="Required" on your Page so it stays in memory forever, though you do lose the Preload() feature then.
or you can modify the Toolkit yourself
or you can cache the content of your page yourself - simply save the Content of your page in some sort of cache (e.g. a Dictionary<Type,UIElement> that maps page type to content) and remove it from the page (set Content to null) when you navigate away from the page and then add it back to the page when you navigate to it and the content is found in the cache. In that case you would probably want to make the Content be a separate UserControl and skip calling InitializeComponent() in the constructor if you retrieve the content from the cache since you can only have one Content and having it defined in a separate UserControl will allow you to get auto-generated code that gets executed in InitializeComponent() that grants you easy access to named elements, registers event handlers etc.
The MSDN Documentation explains when to call WinJS.UI.processAll() yourself in your apps and when it's done for you automatically:
If you aren't using the Blank Application template or if you're adding
the control to a page that you created yourself, you might need to add
a call to WinJS.UI.processAll.
If you added the control to your app's home page (which is usually the default.html file), add a call to WinJS.UI.processAll in your onactivated event handler, as shown in the previous example.
If you added the control to a Page control, you don't need to add a call to WinJS.UI.processAll because the Page control does that for you automatically.
If you added the control to another page that is not your app's home page, handle the DOMContentLoaded event and use the handler to call WinJS.UI.processAll.
What's the reasoning behind the system calling WinJS.UI.processAll() automatically for you inside Page Controls, but not elsewhere?
It's also because the Navigation template (and the Grid template which is derives from the Navigation template) includes at least one data-win-control element so it needs to be processed to function.
We (Microsoft) don't want to put too much in the blank project template because after all it is "blank". So the blank project template just gives you the single page, no navigation, no controls, and thus no need for any processing. You can decide to add that on your own.