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Search found 523 results on 21 pages for 'callbacks'.

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• Silverlight 4 Multithread

  - by DavyMac23

  I'm trying to update my Silverlight 4 UI approx every 1/2 second with new data. I've hooked into a WCF service using net.tcp binding and issuing callbacks from the server. To make sure I get the data from the service as quickly as possible I've started up my proxy on a backround worker inside of my Silverlight App. My question is, how do I get the results from the callback and update the ObservableCollection that is bound to a datagird? I've tried a number of different ways and keep getting the dreaded cross-thread error.

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• a completely decoupled OO system ?

  - by shrini1000

  To make an OO system as decoupled as possible, I'm thinking of the following approach: 1) we run an RMI/directory like service where objects can register and discover each other. They talk to this service through an interface 2) we run a messaging service to which objects can publish messages, and register subscription callbacks. Again, this happens through interfaces 3) when object A wants to invoke a method on object B, it discovers the target object's unique identity through #1 above, and publishes a message on the message service for object B 4) message services invokes B's callback to give it the message 5) B processes the request and sends the response for A on message service 6) A's callback is called and it gets the response. I feel this system is as decoupled as practically possible, but it has the following problems: 1) communication is typically asynchronous 2) hence it's non real time 3) the system as a whole is less efficient. Are there any other practical problems where this design obviously won't be applicable ? What are your thoughts on this design in general ?

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• Handling multiple async HTTP requests in Silverlight serially

  - by Jeb

  Due to the async nature of http access via WebClient or HttpWebRequest in Silverlight 4, when I want to do multiple http get/posts serially, I find myself writing code that looks like this: doFirstGet(someParams, () => { doSecondGet(someParams, () => { doThirdGet(... } }); Or something similar. I'll end up nesting subsequent calls within callbacks usually implemented using lambdas of some sort. Even if I break things out into Actions or separate methods, it still ends up being hard to read. Does anyone have a clean solution to executing multiple http requests in SL 4 serially? I don't need things to be synchronous, I just want serial execution.

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• IPhone: different system timers??

  - by matt

  I have been using mach_absolute_time() for all my timing functions so far. calculating how long between frames ect. I now want to get the exact time touch input events happen using event.timestamp in the touch callbacks. the problem is these two seem to use completely different timers. sure, you can get them both in seconds, but their origins are different and seemingly random... is there any way to sync the two different timers? or is there anyway to get access to the same timer that the touch input uses to generate that timestamp property? otherwise its next to useless.

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• Database triggers / referential integrity and in-memory caching

  - by Ran Biron

  Do you see database triggers / referential integrity rules being used in a way that changes actual data in the database (changing row w in table x causes a change in row y in table z)? If yes, How does this tie-in with the increasing popularity of in-memory caching (memcache and friends)? After all, these actions occur inside the database but the caching system must be aware of them in order to reflect to correct state (or at least invalidate the possibly changed state). I find it hard to believe that callbacks are implemented for such cases. Does anyone have real-world experience with such a setup / real-world experience with considering such a setup and abandoning it (which way did you go? if caching, how do you enforce integrity?)

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• What's a good way to throw and handle events in PHP?

  - by techexpert

  Hi everyone, I am just trying to get a general idea about the event prcessing mechanism in PHP5 in as neat way as possible. First of all I understand that a PHP application is not exactly a persistent type, so the events may not make a lot of sense, but from the OO perspective it might be a very elegant way to "communicate" between the objects. So I am thinking that it would make sense to separate the events on the external events, such as $_POST & $_GET and the internal ones, i.e. function callbacks. As far as the external ones, is it a good idea to process the $_GETs and $_POSTs directly, or is it better to wrap them into an event of some sort? Also, in order to process the internal events, do you have to pass the reference to the event handler/dispatcher to each class so they know how to throw them? I was thinking to use the PEAR EventDispatcher to do the work, but I am open to other suggestions. Thank you!

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• WM6x IMAPIAdviseSink::OnNotify threading issues

  - by violet313

  specifically WM6x, winCE5x Now my current understanding from trawling the msdn etal is that the IMAPIAdviseSink::OnNotify callback can be made from any old thread; from (ce)mapi or perhaps even from a third-party service provider. Under WM6x, i cannot seem to coax an in-thread response by invoking HrThisThreadAdviseSink, since while this function is declared in mapiutil.h, a definition appears not to exist (in cemapi.lib or wherever??) ~But i notice that all the OnNotify callbacks i receive derive from windows messages that i am receiving on my thread (=looks to me like an in-thread implementation in any case under cemapi)... So, can anyone confirm that this is infact always the case -or am i just getting lucky right now? ah, i should add that my advise source is IMAPISession::Advise erm i should also say that i might have cross-posted this on the msdn forum -but they're mostly numptys over there,,

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• Is Classic ADO still viable for a mixed managed/unmanaged App?

  - by Andy Dent

  We have a complex architecture with much logic in unmanaged code that needs database access. Currently this is via ODBC drivers and MFC classes and we're considering the issues of migrating our abstraction layer to use ADO or ADO.Net. In the latter case we'd have to be pushing database logic back up into the .Net layer. I'm trying to decide if the pain of invoking the database via .Net callbacks is offset by the improvements in ADO.Net. The Wikipedia comparison was interesting although I'm not sure I believe all the points in the comparison table (eg: does ADO.Net always use XML to pass data?). A 2005 comparison shows ADO.Net performing dramatically faster. Microsoft's guide to ADO.Net for ADO programmers suggests we will gain much from going to ADO.Net especially the way that data is available in native (.Net) types rather than solely through OLEAutomation's Variant.

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• Good code visualization / refactoring tools for C++?

  - by Paul D.

  I've found myself coming across a lot of reasonably large, complicated codebases at work recently which I've been asked to either review or refactor or both. This can be extremely time consuming when the code is highly concurrent, makes heavy use of templates (particularly static polymorphism) and has logic that depends on callbacks/signals/condition variables/etc. Are there any good visualization tools for C++ period, and of those are there any that actually play well with "advanced" C++ features? Anything would probably be better than my approach now, which is basically pen+paper or stepping through the debugger. The debugger method can be good for following a particular code path, but isn't great for seeing the big picture you really need when doing serious refactoring. EDIT: I should mention that Visual Studio plugins aren't going to be a lot of help to me, since our stuff is mostly Linux-only.

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• jquery validation plugin - different treatment for display errors vs. clearing errors

  - by RyOnLife

  I am using the popular jQuery Validation Plugin. It's very flexible with regards to when validations are run (onsubmit, onfocusout, onkeyup, etc.). When validations do run, as appropriate, errors are both displayed and cleared. Without hacking the plugin core, I'd like a way to split the behavior so: Errors are only displayed onsubmit But if the user subsequently enters a valid response, errors are cleared onsubmit, onfocusout, etc. Just trying to create a better user experience: Only yell at them when they submit, yet still get the errors out of their face as soon as possible. When I ran through the options, I didn't see the callbacks necessary to accomplish this. I'd like to make it work without having to hack the plugin core. Anyone have some insights? Thanks.

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• What should I do to recompile my static library (originally written in VS6) in visual studio 2008?

  - by user370387

  There is a static library A with c++ classes wrapped by a C API in VS6. I developed a static library B in VS6 using callbacks from library A. The library B is used by the program C (commercial software) as a "user defined library" and linked to produce the program D. Questions: 1) When program C uses VS 6 it works, should it work fine with VS 2008? Because it doesn't. 2) When I tried to recompile library B in VS 2008 it gave me a .lib file with only 28KB, and the old one had more than 2MB. Is it ok? What Am I probably doing wrong? Thanks in advance

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• why Observable snapshot observer vector

  - by han14466

  In Observable's notifyObservers method, why does the coder use arrLocal = obs.toArray();? Why does not coder iterate vector directly? Thanks public void notifyObservers(Object arg) { Object[] arrLocal; synchronized (this) { /* We don't want the Observer doing callbacks into * arbitrary code while holding its own Monitor. * The code where we extract each Observable from * the Vector and store the state of the Observer * needs synchronization, but notifying observers * does not (should not). The worst result of any * potential race-condition here is that: * 1) a newly-added Observer will miss a * notification in progress * 2) a recently unregistered Observer will be * wrongly notified when it doesn't care */ if (!changed) return; arrLocal = obs.toArray(); clearChanged(); } for (int i = arrLocal.length-1; i>=0; i--) ((Observer)arrLocal[i]).update(this, arg); }

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• Avoid stuck calling callback

  - by andlomba

  Hello all, This is a question about generic c++ event driven applications design. Lets assume that we have two threads, a "Dispatcher" (or "Engine"...) and a "Listener" (or "Client"...). Let's assume that I write the Dispatcher code, and release it as a library. I also write the Listener interface, of course. When the Dispatcher executes (after Listener registration) listenerInstance.onSomeEvent(); the event handling code will actually be executed by the Dispatcher thread, so if the person that implements the Listener writes something like void Listener::onSomeEvent() { while(true) ; } The Dispatcher will stuck forever. Is there a "plain old c++" (I mean no boost or libsigc++) way to "decouple" the two classes, so I can be sure that my Dispatcher will work fine whatever the Listeners does in the callbacks? bye and thanks in advance, Andrea

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• Is it considered bad practice to have ViewModel objects hold the Dispatcher?

  - by stiank81

  My WPF application is structured using the MVVM pattern. The ViewModels will communicate asynchronously with a server, and when the requested data is returned a callback in the ViewModel is triggered, and it will do something with this data. This will run on a thread which is not the UI Thread. Sometimes these callbacks involve work that needs to be done on the UI thread, so I need the Dispatcher. This might be things such as: Adding data to an ObservableCollection Trigger Prism commands that will set something to be displayed in the GUI Creating WPF objects of some kind. I try to avoid the latter, but the two first points here I find to be reasonable things for ViewModels to do. So; is it okay to have ViewModels hold the Dispatcher to be able to Invoke commands for the UI thread? Or is this considered bad practice? And why?

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• jQuery: what is it "forbidden" to do in plain Javascript

  - by flybywire

  A jQuery best practices question. I am writing a very jQuery intensive web page. I am new to jQuery and notice its power, but as I come with heavy javascript experience and knowledge, my question is: What should be done in jQuery and what in plain javascript. For example, there are callbacks that send a plain DOM object as an argument. Should I use that or should I wrap it ( like $(this)). Does it matter if I do this.x=y or $(this).attr("x", y).

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• jQuery.Form wont submit

  - by kim

  Im´trying to submit a form without refreshing the page, but I´m having a problem. When I click submit the page refreshes and anothing gets posted. Here is the code, what am I doing wrong? (I´m a newbie) jQuery 1.4.2 and the jQuery Form Plugin 2.43 is present. tnx $(document).ready(function() { var options = { target: '#output2', url: https://graph.facebook.com/<%=fbUid%>/feed, type: post, clearForm: true // clear all form fields after successful submit //dataType: null // 'xml', 'script', or 'json' (expected server response type) //resetForm: true // reset the form after successful submit // $.ajax options can be used here too, for example: //timeout: 3000 }; // bind to the form's submit event $('#fbPostStatus').submit(function() { // inside event callbacks 'this' is the DOM element so we first // wrap it in a jQuery object and then invoke ajaxSubmit $(this).ajaxSubmit(options); // !!! Important !!! // always return false to prevent standard browser submit and page navigation return false; }); });

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• nodejs, mongodb - How do I operate on data from multiple queries?

  - by Ryan

  Hi all, I'm new to JS in general, but I am trying to query some data from MongoDB. Basically, my first query retrieves information for the session with the specified session id. The second query does a simple geospacial query for documents with a location near the specified location. I'm using the mongodb-native javascript driver. All of these query methods return their results in callbacks, so they're non-blocking. This is the root of my troubles. What I'm needing to do is retrieve the results of the second query, and create an Array of sessionIds of all the returned documents. Then I'm going to pass those to a function later. But, I can't generate this array and use it anywhere outside the callback. Does anyone have any idea how to properly do this? http://dpaste.org/wXiE/

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• Creating and releasing objects in the same method, while using self as delegate

  - by user200341

  In objective-c you are responsible for releasing objects you allocate, but what happens when you allocate an object in a method, assign self as the objects delegate, and then release the object. The callbacks from the newly created (and released) object fails at this point, or rather, doesn't happen. - (void)doSomething { MyObj *myObj = [[MyObj alloc] init]; myObj.delegate = self; [myObj performOperation]; [myObj release]; } - (void)callbackMethodFromMyObj:(NSString *)message { NSLog(message); } I can't release the object until the callback has occurred, and I can't avoid releasing the object in the same method that creates it (because it exists outside the scope). One way of doing it would be to pass the object along in the call-back and release it in the callback, but is this the right way to go about this?

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• GLUT multiple Windows and OpenGL context

  - by user3511595

  I would like to use GLUT 3.7 Window Toolkit in a program written in php because i saw that there was a binding in php. I am interesting in having multiple windows ! In order to have a clean code, i was wondering to separate on the one hand the window toolkit and on the other hand the OpenGL implementation. I hope that i can program event with the glut callbacks in php then the application get the events and can interacts ! But i don't know how to draw in each window from php with opengl ? They say in the man page that each glut window has an opengl context. How to get each context ? Can i render offscreen with each context ?

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• jQuery jqXHR - cancel chained calls, trigger error chain

  - by m0sa

  I am creating a ajax utility for interfacing with my server methods. I would like to leverage jQuery 1.5+ deferred methods from the object returned from the jQuery.ajax() call. The situation is following. The serverside method always returns a JSON object: { success: true|false, data: ... } The client-side utility initiates the ajax call like this var jqxhr = $.ajax({ ... }); And the problem area: jqxhr.success(function(data, textStatus, xhr) { if(!data || !data.success) { ???? // abort processing, trigger error } }); return jqxhr; // return to caller so he can attach his own handlers So the question is how to cancel invocation of all the callers appended success callbacks an trigger his error handler in the place mentioned with ???? ? The documentation says the deferred function invocation lists are FIFO, so my success handler is definitely the first one.

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• Rebuild whole page on callback?

  - by AJ

  Hello, In asp.net is it a requirement to rebuild the whole page during every callback? For example my web page is split into three distinct areas and I have an update panel for each area. Lets say I want to update the third area, do I have to bother with any processing of the other two areas? For example lets say there is a grid view in area two. The update panel in area three callbacks to update its content. Do I have to rebind the grid in area two? Thanks, AJ

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• Understanding "this" keyword

  - by Raffaele

  In this commit there is a change I cannot explain deferred.done.apply( deferred, arguments ).fail.apply( deferred, arguments ); becomes deferred.done( arguments ).fail( arguments ); AFAIK, when you invoke a function as a member of some object like obj.func(), inside the function this is bound to obj, so there would be no use invoking a function through apply() just to bound this to obj. Instead, according to the comments, this was required because of some preceding $.Callbacks.add implementation. My doubt is not about jQuery, but about the Javascript language itself: when you invoke a function like obj.func(), how can it be that inside func() the this keyword is not bound to obj?

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• How to use 'this' in jQuery plugin callback?

  - by Bondye

  At the moment I am creating a jQuery plugin. I am facing a problem when using a callback. Plugin code $.fn.bondye = function (options) { var settings = $.extend({ callback: function () {} }, options); return this.each(function () { $(this).addClass('test'); settings.callback(); }); }; How I want to execute the code $(".myDiv").bondye({ callback: function () { $(this).removeClass("test"); } }); jsFiddle example: http://jsfiddle.net/HEJtm/1/ But I aint able to do anything with the div within the callback. I used http://learn.jquery.com/plugins/advanced-plugin-concepts/ to learn developing jQuery plugins, but I cannot find anything about callbacks.

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• Solution for using `this` keyword in ajax calls within methods?

  - by dqhendricks

  I am creating a JavaScript class. Some of the methods contain AJAX calls using JQuery. The problem I am comming accross is that I cannot use the this keyword within the AJAX callbacks due to a change in scope. I have come up with a hackey solution, but I am wondering what is the best practice way around this? Here is an example: var someClass = function() { var someElement = $('form'); this.close = function() { someElement.remove(); }; this.query = function() { $.ajax({ url: someurl, success: function() { this.close(); // does not work because `this` is no longer the parent class } }); }; };

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• What is the most elegant way to access current_user from the models? or why is it a bad idea?

  - by TheLindyHop

  So, I've implemented some permissions between my users and the objects the users modify.. and I would like to lessen the coupling between the views/controllers with the models (calling said permissions). To do that, I had an idea: Implementing some of the permission functionality in the before_save / before_create / before_destroy callbacks. But since the permissions are tied to users (current_user.can_do_whatever?), I didn't know what to do. This idea may even increase coupling, as current_user is specifically controller-level. The reason why I initially wanted to do this is: All over my controllers, I'm having to check if a user has the ability to save / create / destroy. So, why not just return false upon save / create / destroy like rails' .save already does, and add an error to the model object and return false, just like rails' validations? Idk, is this good or bad? is there a better way to do this?

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