In my silverlight 4.0 application, at one point, after user pushes a button, I have to create few UI objects that take some time (5-10seconds). During this time UI freezes of course. I decided to put creation of those objects in a background worker so UI could at least show progress bar.
But this solution does not work. To create UI object you have to be in UI thread.
If I put creation of those object inside Dispatcher.BeginInvoke() than again my UI freezes. In most cases without even showing progress bar. Is there a way around this?
Can I show progress bar while silverlight creates UI objects in the background?
Have a look at this forum post. It may help.
Instead of using:
System.Windows.Threading.Dispatcher.BeginInvoke(() => {});
They use:
System.Windows.Deployment.Current.Dispatcher.BeginInvoke(() => {});
You can try displaying a custom message before creating UI objects inside BeginInvoke().
Example:
private void CreateObjects()
{
myMsg.Text = "Loading...";
Dispatcher.BeginInvoke(() => { AddObjects() });
}
Once all objects are created, disable the message.
You can try the similar thing with Progress Bar also.
Related
I have a custom module that contains a button. The button click performs a process that sometimes takes 5-10 seconds to complete. Is there a way in Kentico to display a custom busy message like the "Loading" message that Kentico displays during lengthy processes? I would like to show the same "Loading" msg that Kentico shows with my own custom message.
If your module is built using the out of the box page templates and webparts, this is included by default. If it is not and you're using custom aspx template pages, you'll need to ensure that the page in inherited properly and add that in. You might want to reference another out of the box module which is using code already like the Users in the Membership module.
Yes, but it depends on how things are set up.
If the button executes an Ajax Panel (it does a postback through an ajax call), then you can capture the ajax call and put your loading message there.
<script type="text/javascript>
var AjaxHandler = Sys.WebForms.PageRequestManager.getInstance();
AjaxHandler.add_beginRequest(beginRequestHandler);
AjaxHandler.add_endRequest(endRequestHandler);
function beginRequestHandler(sender, args) {
// Waiting
}
function endRequestHandler(sender, args) {
// close waiting
}
</script>
If you have it postbacking on the page, you can try to put a hook when the button is clicked to show the waiting, when the page refreshes then the waiting will of course be gone.
$("#mybutton").click(function() {
// Waiting
});
My windows 10 IOT core application uses SPI to collect change notifications of
many entities. There are excellent examples for launching a timer to get SPI data, update data and binding UI elements to this data. The result is anytime SPI gets some data about a changed entity, the data that drives the UI is updated and any UI element bound to this data is updated. I can even change what subset of data is displayed on this page by using two way bindings to track the selected items on a list.
Just like the many examples, my code is structured as follows:
public async void Init_SPI()
{
....
periodicTimer = new Timer(this.TimerCallback, null, 0, 10);
} // public async void Init_SPI()
private void TimerCallback(object state)
{
/* UI updates must be invoked on the UI thread */
var task =
this.Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
{ ... update states of data that many be bound to UI element
My issue / question:
I don't see how to update data for multiple pages based on the above, since this.variable refers to the UI thread of the page that launched the timer.
It would be too inefficient to update a static class and have the multiple pages continuously poll this static data to make the UI track these large number of element.
My only thought at present is to code all the XAML pages in one page and tab between these "virtual" pages. I would rather have multiple pages to keep the functionality of these pages separated.
Any suggestions for how I could update multiple pages from data read on a SPI port would be appreciated.
Regards,
John
Sorry for a very late answer, but my solution would be to still create "real" pages -- but "relayed" the data only to the currently visible page. So whenever a page becomes visible I would have made the internals of the code piece above { ... update states of data [...] to point out that page.
This could be achieved with a simple switch statement, or by a simple interface with a HandleSpiData(TheSpiData) method -- or even a simple Action<YourSpiData>.
Which is the recommended way of waiting for a page to load/reflow in Awesomium.NET 1.7+ when running in a non-UI environment? I've tried this approach:
using (var view = WebCore.CreateWebView(...))
{
// Load page, resize view etc.
// ...
do
{
System.Threading.Thread.Sleep(50);
WebCore.Update();
} while (view.IsLoading);
// Do something with the page
// ...
}
However, this doesn't seem to work reliably - if I render the page to a bitmap after the loop it pretty often comes out blank (but not always). Is there a better way of waiting for page load/reflow?
Try subscribing to the WebView.DocumentReady event.
How you do it depends on what you are waiting for. The code in the question should work when waiting for a page to load, but resizing the view is different - check out the BitmapSurface.Resized event, it fires when the BitmapSurface has been resized and updated its buffer.
I have a problem that the ViewWillAppear method for a UIView does not fire when the application returns from the background. This is a problem, as my main application screen is showing values that are retrieved from the user settings, and if the user has changed these while the application was in the background I need to have the screen refreshed. I have read that one should register for the UIApplicationWillEnterForegroundNotification using NSNotificationCenter.
How do you do this in MonoTouch? Or does anyone know an alternate way of ensuring that the screen is always kept up to date, even when returning from the background?
You could try something along the lines of:
//Register for the notification somewhere in the app
NSNotificationCenter.DefaultCenter.AddObserver(UIApplication.WillEnterForegroundNotification, EnteredForeground);
//snip
void EnteredForeground (NSNotification notification)
{
// do your stuff here
}
Bear in mind you would need to do this for every view controller you'd like to update when enterting from the background!
I have implemented MVP pattern in my GXT project. The system registers customers as part of it function. Also the system user can search for the registered user providing the id.
i have added an OnClick event to the "search customer" button.
/* On click search button */
view.getBtnSearch().addListener(Events.OnClick, new Listener<BaseEvent>() {
#Override
public void handleEvent(BaseEvent be) {
eventBus.fireEvent(new CustomerRegistrationTabSelectionEvent(0, false));
eventBus.fireEvent(new CustomerFetchEvent(view.getValueCustSearchParameter(), view.getValueCustSearchValue(), true));
}
});
The CustomerRegistrationTabSelectionEvent does select the relevant tab and enables other tabs. Thats all it does.
Here is the handler for the custom event CustomerFetchEvent.
eventBus.addHandler(CustomerFetchEvent.TYPE, new CustomerFetchEventHandler() {
#Override
public void fetchCustomer(CustomerFetchEvent event) {
searchCustomer(event.getParameter(), event.getParameterValue(), event.isOpenFirstTab());
}
});
The issue is the search customer method is executed multiple times and if there is a invalid search the error message dialog shows multiple popups. Within the searchCustomer method i call for service which fetch me the customer data or show the popup error message if the search is invalid.
im using GXT 2.2.5 and JRE 1.6.
Could anyone help me in finding out why the code is executed multiple times?
Added Later:
When i run the application first time the code is only executed only once, therefore only 1 popup. Then i logout of the system and log in again (navigating to the same page where the "search customer" button exists.) and the code is executed twice. Likewise equal to the number of times i create/navigate to the particular page, the code executes. Is it actually adding the event handler code without removing the last one every time i recreate the page?
Yes, it seems that 'addHandler' adds handler multiple times, but stores previous context. Your code should add handlers only once, on initialization phase. You can check the number of handlers with 'getHandlerCount' method.
Ya. I fixed it!Here is the solution Unbinding presenters necessary in GWT
U can read more here. http://draconianoverlord.com/2010/11/23/gwt-handlers.html
what happened actually was, the presenter objects where i have registered with HandlerManager to receive events were not garbage collected. Because though i remove the reference to the presenters still the HandlerManager holds a reference to those objects. So every time i kept on creating new presenters on top of the old presenters of the same class. so a event is listened by multiple objects of the same class. so u need to ensure that the unused presenters are garbage collected by removing the registered handlers
in HandlerManager.