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  • Asp.Net MVC2 RenderAction changes page mime type?

    - by Gabe Moothart
    It appears that calling Html.RenderAction in Asp.Net MVC2 apps can alter the mime type of the page if the child action's type is different than the parent action's. The code below (testing in MVC2 RTM), which seems sensible to me, will return a result of type application/json when calling Home/Index. Instead of dispylaying the page, the browser will barf and ask you if you want to download it. My question: Am I missing something? Is this a bug? If so, what's the best workaround? controller: public class HomeController : Controller { public ActionResult Index() { ViewData[ "Message" ] = "Welcome to ASP.NET MVC!"; return View(); } [ChildActionOnly] public JsonResult States() { string[] states = new[] { "AK", "AL", "AR", "AZ", }; return Json(states, JsonRequestBehavior.AllowGet); } } view: <h2><%= Html.Encode(ViewData["Message"]) %></h2> <p> To learn more about ASP.NET MVC visit <a href="http://asp.net/mvc" title="ASP.NET MVC Website">http://asp.net/mvc</a>. </p> <script> var states = <% Html.RenderAction("States"); %>; </script>

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  • Handle URI hacking gracefully in ASP.NET

    - by asbjornu
    I've written an application that handles most exceptions gracefully, with the page's design intact and a pretty error message. My application catches them all in the Page_Error event and there adds the exception to HttpContext.Curent.Context.Items and then does a Server.Transfer to an Error.aspx page. I find this to be the only viable solution in ASP.NET as there seems to be no other way to do it in a centralized and generic manner. I also handle the Application_Error and there I do some inspection on the exception that occurred to find out if I can handle it gracefully or not. Exceptions I've found I can handle gracefully are such that are thrown after someone hacking the URI to contain characters the .NET framework considers dangerous or basically just illegal at the file system level. Such URIs can look like e.g.: http://exmample.com/"illegal" http://example.com/illegal"/ http://example.com/illegal / (notice the space before the slash at the end of the last URI). I'd like these URIs to respond with a "404 Not Found" and a friendly message as well as not causing any error report to be sent to avoid DDOS attack vectors and such. I have, however, not found an elegant way to catch these types of errors. What I do now is inspect the exception.TargetSite.Name property, and if it's equal to CheckInvalidPathChars, ValidatePath or CheckSuspiciousPhysicalPath, I consider it a "path validation exception" and respond with a 404. This seems like a hack, though. First, the list of method names is probably not complete in any way and second, there's the possibility that these method names gets replaced or renamed down the line which will cause my code to break. Does anyone have an idea how I can handle this less hard-coded and much more future-proof way? PS: I'm using System.Web.Routing in my application to have clean and sensible URIs, if that is of any importance to any given solution.

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  • How does one convert 16-bit RGB565 to 24-bit RGB888?

    - by jleedev
    I’ve got my hands on a 16-bit rgb565 image (specifically, an Android framebuffer dump), and I would like to convert it to 24-bit rgb888 for viewing on a normal monitor. The question is, how does one convert a 5- or 6-bit channel to 8 bits? The obvious answer is to shift it. I started out by writing this: uint16_t buf; while (read(0, &buf, sizeof buf)) { unsigned char red = (buf & 0xf800) >> 11; unsigned char green = (buf & 0x07c0) >> 5; unsigned char blue = buf & 0x003f; putchar(red << 3); putchar(green << 2); putchar(blue << 3); } However, this doesn’t have one property I would like, which is for 0xffff to map to 0xffffff, instead of 0xf8fcf8. I need to expand the value in some way, but I’m not sure how that should work. The Android SDK comes with a tool called ddms (Dalvik Debug Monitor) that takes screen captures. As far as I can tell from reading the code, it implements the same logic; yet its screenshots are coming out different, and white is mapping to white. Here’s the raw framebuffer, the smart conversion by ddms, and the dumb conversion by the above algorithm. (By the way, this conversion is implemented in ffmpeg, but it’s just performing the dumb conversion listed above, leaving the LSBs at all zero.) I guess I have two questions: What’s the most sensible way to convert rgb565 to rgb888? How is DDMS converting its screenshots?

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  • Practical value for concurrent-request-timeout parameter

    - by Andrei
    In the Seam Reference Guide, one can find this paragraph: We can set a sensible default for the concurrent request timeout (in ms) in components.xml: <core:manager concurrent-request-timeout="500" /> However, we found that 500 ms is not nearly enough time for most of the cases we had to deal with, especially with the severe restriction seam places on conversation access. In our application we have a combination of page scoped ajax requests (triggered by various use actions), some global scoped polling notification logic (part of the header, so included in every page) and regular links that invoke actions and/or navigate to other pages. Therefore, we get the dreaded concurrent access to conversation exception way too often, even without any significant load on the site. After researching the options for quite a bit, we ended up bumping this value to several seconds (we're debating whether to bump it up to 10s), as none of the recommended solutions seemed able to solve our issue completely (even forcing a global queue for all the ajax requests would still leave us exposed to a user deciding to click a link right when one of our polling calls was in progress). And we'd much rather have the users wait for a second or two instead of getting an error page just because they clicked a link at the wrong moment. And now to the question: is there something obvious we're missing (like a way to allow concurrent access to conversations and taking care of the needed locking ourselves, for instance :)? How do people solve this problem (ajax requests mixed with user driven interaction) in seam? Disabling all the links on the page while ajax requests are in progress (as suggested by one blog page) is really not a viable option. Any other suggestions? TIA, Andrei

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  • Adding a Combobox to a DataGrid in Silverlight

    - by bplus
    I can add a Combobox to a DataGrid using following xmal: <local:DataGridTemplateColumn Header="SomeHeader" Width="106" HeaderStyle="{StaticResource headerAlignRightStyle}" CellStyle="{StaticResource cellAlignRightStyle}"> <local:DataGridTemplateColumn.CellTemplate> <DataTemplate> <TextBlock Text="{Binding SomeProp}" Margin="4"/> </DataTemplate> </local:DataGridTemplateColumn.CellTemplate> <local:DataGridTemplateColumn.CellEditingTemplate> <DataTemplate> <ComboBox x:Name="SomeCombo" SelectionChanged="SomeCombo_SelectionChanged" ItemsSource="{Binding SomeList}" DisplayMemberPath="Name" /> </DataTemplate> </local:DataGridTemplateColumn.CellEditingTemplate> </local:DataGridTemplateColumn> However what I can't figure out is a sensible way to get the row that was combox is bound to. i.e. when handling the combobox SelectionChanged event I have no way of knowing what what row the combobox belongs to. Particularly I don't know what object in the DataGrid datasource that the combobox is refering to. Any help would be much appreciated.

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  • Assigning static final int in a JUnit (4.8.1) test suite

    - by Dr. Monkey
    I have a JUnit test class in which I have several static final ints that can be redefined at the top of the tester code to allow some variation in the test values. I have logic in my @BeforeClass method to ensure that the developer has entered values that won't break my tests. I would like to improve variation further by allowing these ints to be set to (sensible) random values in the @BeforeClass method if the developer sets a boolean useRandomValues = true;. I could simply remove the final keyword to allow the random values to overwrite the initialisation values, but I have final there to ensure that these values are not inadvertently changed, as some tests rely on the consistency of these values. Can I use a constructor in a JUnit test class? Eclipse starts putting red underlines everywhere if I try to make my @BeforeClass into a constructor for the test class, and making a separate constructor doesn't seem to allow assignment to these variables (even if I leave them unassigned at their declaration); Is there another way to ensure that any attempt to change these variables after the @BeforeClass method will result in a compile-time error? Can I make something final after it has been initialised?

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  • Database design for invoices, invoice lines & revisions

    - by FreshCode
    I'm designing the 2nd major iteration of a relational database for a franchise's CRM (with lots of refactoring) and I need help on the best database design practices for storing job invoices and invoice lines with a strong audit trail of any changes made to each invoice. Current schema Invoices Table InvoiceId (int) // Primary key JobId (int) StatusId (tinyint) // Pending, Paid or Deleted UserId (int) // auditing user Reference (nvarchar(256)) // unique natural string key with invoice number Date (datetime) Comments (nvarchar(MAX)) InvoiceLines Table LineId (int) // Primary key InvoiceId (int) // related to Invoices above Quantity (decimal(9,4)) Title (nvarchar(512)) Comment (nvarchar(512)) UnitPrice (smallmoney) Revision schema InvoiceRevisions Table RevisionId (int) // Primary key InvoiceId (int) JobId (int) StatusId (tinyint) // Pending, Paid or Deleted UserId (int) // auditing user Reference (nvarchar(256)) // unique natural string key with invoice number Date (datetime) Total (smallmoney) Schema design considerations 1. Is it sensible to store an invoice's Paid or Pending status? All payments received for an invoice are stored in a Payments table (eg. Cash, Credit Card, Cheque, Bank Deposit). Is it meaningful to store a "Paid" status in the Invoices table if all the income related to a given job's invoices can be inferred from the Payments table? 2. How to keep track of invoice line item revisions? I can track revisions to an invoice by storing status changes along with the invoice total and the auditing user in an invoice revision table (see InvoiceRevisions above), but keeping track of an invoice line revision table feels hard to maintain. Thoughts? 3. Tax How should I incorporate sales tax (or 14% VAT in SA) when storing invoice data?

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  • Django Models / SQLAlchemy are bloated! Any truly Pythonic DB models out there?

    - by Luke Stanley
    "Make things as simple as possible, but no simpler." Can we find the solution/s that fix the Python database world? from someAmazingDB import * class Task (model): title = '' isDone = False db.taskList = [] #or db.taskList = expandableTypeCollection(Task) #not sure what this syntax would be db['taskList'].append(Task(title='Beat old sql interfaces',done=False)) db.taskList.append(Task('Illustrate different syntax modes',True)) #at this point it should autosave #we should be able to reload the console and access like: >> from someAmazingDB import * >> print 'Done tasks:' >> for task in db.taskList: >> if task.done: >> print task 'Illustrate different syntax modes' I'm a fan of Python, webPy and Cherry Py, and KISS in general. We're talking automatic Python to SQL type translation or NoSQL. We don't have to totally be SQL compatible! Just a scalable subset or ignore it! Re:model changes, it's ok to ask the developer when they try to change it or have a set of sensible defaults. Here is the challenge: The above code should work with very little modification or thinking required. Why must we put up with compromise when we know better? It's 2010, we should be able to code scalable, simple databases in our sleep. If you think this is important, please upvote!

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  • intelligent path truncation/ellipsis for display

    - by peterchen
    I am looking for an existign path truncation algorithm (similar to what the Win32 static control does with SS_PATHELLIPSIS) for a set of paths that should focus on the distinct elements. For example, if my paths are like this: Unit with X/Test 3V/ Unit with X/Test 4V/ Unit with X/Test 5V/ Unit without X/Test 3V/ Unit without X/Test 6V/ Unit without X/2nd Test 6V/ When not enough display space is available, they should be truncated to something like this: ...with X/...3V/ ...with X/...4V/ ...with X/...5V/ ...without X/...3V/ ...without X/...6V/ ...without X/2nd ...6V/ (Assuming that an ellipsis generally is shorter than three letters). This is just an example of a rather simple, ideal case (e.g. they'd all end up at different lengths now, and I wouldn't know how to create a good suggestion when a path "Thingie/Long Test/" is added to the pool). There is no given structure of the path elements, they are assigned by the user, but often items will have similar segments. It should work for proportional fonts, so the algorithm should take a measure function (and not call it to heavily) or generate a suggestion list. Data-wise, a typical use case would contain 2..4 path segments anf 20 elements per segment. I am looking for previous attempts into that direction, and if that's solvable wiht sensible amount of code or dependencies.

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  • Date from String using NSDateFormatter regardless 12h-24h setting

    - by maxf99
    Hello everybody, Today my question is about date formats and strings. My application downloads some strings representing dates from the internet. The date format is always like this: "2010-05-24 at 20:45" I need to convert this string into an NSDate object in order to perform some date manipulations. I tried this code: NSString * dateString = @"2010-05-24 at 20:45" // actually downloaded from the internet NSDateFormatter * myDateFormatter = [[NSDateFormatter alloc] init]; [myDateFormatter setDateFormat:@"yyyy-MM-dd 'at' HH:mm"]; NSDate * dateFromString = [myDateFormatter dateFromString:dateString]; This seems to work perfectly fine as long as the iPhone is set to 24h clock. As long as I switch to 12h clock in the general settings the NSDate object is not created (and the application happily crashes) I have read others having similar problems but I don't seem to find a solution. Now the questions: It doesn't make sense to me that the NSDateFormatter is sensible to user settings as long as I am specifying which format it is supposed to use to parse the string (which is not modifiable because it comes from the web), what's the use of checking user settings? More important, how can I get my task performed (to get an NSDate object from the string regardless the user settings)?

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  • Create an anonymous type object from an arbitrary text file

    - by Robert Harvey
    I need a sensible way to draw arbitrary text files into a C# program, and produce an arbitrary anonymous type object, or perhaps a composite dictionary of some sort. I have a representative text file that looks like this: adapter 1: LPe11002 Factory IEEE: 10000000 C97A83FC Non-Volatile WWPN: 10000000 C93D6A8A , WWNN: 20000000 C93D6A8A adapter 2: LPe11002 Factory IEEE: 10000000 C97A83FD Non-Volatile WWPN: 10000000 C93D6A8B , WWNN: 20000000 C93D6A8B Is there a way to get this information into an anonymous type object or some similar structure? The final anonymous type might look something like this, if it were composed in C# by hand: new { adapter1 = new { FactoryIEEE = "10000000 C97A83FC", Non-VolatileWWPN = "10000000 C93D6A8A", WWNN = "20000000 C93D6A8A" } adapter2 = new { FactoryIEEE = "10000000 C97A83FD", Non-VolatileWWPN = "10000000 C93D6A8B", WWNN = "20000000 C93D6A8B" } } Note that, as the text file's content is arbitrary (i.e. the keys could be anything), a specialized solution (e.g. that looks for names like "FactoryIEEE") won't work. However, the structure of the file will always be the same (i.e. indentation for groups, colons and commas as delimiters, etc). Or maybe I'm going about this the wrong way, and you have a better idea?

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  • registration 0.8 alpha activation problem

    - by craphunter
    Got the following error: Exception Type: TypeError at /accounts/account/activate/success/ Exception Value: activate() takes at least 2 non-keyword arguments (1 given) My view: def activate(request, backend, template_name='registration/activation_complete.html', success_url=None, extra_context=None, **kwargs): backend = get_backend(backend) account = backend.activate(request, **kwargs) if account: if success_url is None: to, args, kwargs = backend.post_activation_redirect(request, account) return redirect(to, *args, **kwargs) else: return redirect(success_url) if extra_context is None: extra_context = {} context = RequestContext(request) for key, value in extra_context.items(): context[key] = callable(value) and value() or value return render_to_response(template_name, kwargs, context_instance=context) My url: urlpatterns = patterns('', url(r'^activate/complete/$', direct_to_template, { 'template': 'registration/activation_complete.html' }, name='registration_activation_complete'), # Activation keys get matched by \w+ instead of the more specific # [a-fA-F0-9]{40} because a bad activation key should still get to the view; # that way it can return a sensible "invalid key" message instead of a # confusing 404. url(r'^activate/(?P<activation_key>\w+)/$', activate, { 'backend': 'registration.backends.default.DefaultBackend' }, name='registration_activate'), url(r'^register/$', register, { 'backend': 'registration.backends.default.DefaultBackend' }, name='registration_register'), url(r'^register/complete/$', direct_to_template, { 'template': 'registration/registration_complete.html' }, name='registration_complete'), url(r'^register/closed/$', direct_to_template, { 'template': 'registration/registration_closed.html' }, name='registration_disallowed'), (r'', include('registration.auth_urls')), url(r'^account/activate/(?P<activation_key>\w+)/$', 'registration.views.activate', {'success_url': 'account/activate/success/'}, name='registration_activate2'), url(r'^account/activate/success/$', direct_to_template, {'template': 'registration/activation_complete.html'}, name='registration_activation_complete'), ) What do I do wrong? Thanks!

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  • how to push different local git branches to heroku/master

    - by lsiden
    Heroku has a policy of ignoring all branches but 'master'. While I'm sure Heroku's designers have excellent reasons for for this policy (I'm guessing for storage and performance optimization), the consequence to me as a developer is that whatever local topic branch I may be working on, I would like an easy way to switch Heroku's master to that local topic branch and do a "git push heroku -f" to over-write master on Heroku. What I got from reading the "Pushing Refspecs" section of http://progit.org/book/ch9-5.html is git push -f heroku local-topic-branch:refs/heads/master What I'd really like is a way to set this up in the config file so that "git push heroku" always does the above, replacing local-topic-branch with the name of whatever my current branch happens to be. If anyone knows how to accomplish that, please let me know! The caveat for this, of course, is that this is only sensible if I am the only one who can push to that Heroku app/repository. A test or QA team might manage such a repository to try out different candidate branches, but they would have to coordinate so that they all agree on what branch they are pushing to it on any given day. Needless to say, it would also be a very good idea to have a separate remote repository (like Github) without this restriction for backing everything up to. I'd call that one "origin" and use "heroku" for Heroku so that "git push" always backs up everything to origin, and "git push heroku" pushes whatever branch I'm currently on to Heroku's master branch, overwriting it if necessary. Can anybody tell me if this would work? [remote "heroku"] url = [email protected]:my-app.git push = +refs/heads/*:refs/heads/master I'd like to hear from someone more experienced before I begin to experiment, although I suppose I could create a dummy app on Heroku and experiment with that. As for fetching, I don't really care if the Heroku repository is write-only. I still have a separate repository, like Github, for backup and cloning of all my work. Footnote: This question is similar to, but not quite the same as http://stackoverflow.com/questions/1489393/good-git-deployment-using-branches-strategy-with-heroku

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  • Automatic web form testing/filling

    - by Polatrite
    I recently became lead on getting an inordinate amount of testing done in a very short period of time. We have many different web forms, using custom (Telerik) controls that need to be tested for proper data validation and sensible handling of the data. Some of the forms are several pages long with 30-80 different controls for data entry. I am looking for a software solution (that is free) that would allow me to automate the process of filling in these forms by designing a script, or using a UI. The other requirement is that I can't use any browsers but IE6 (terrible, I know). I have previously used AutoHotkey to great success for automatic Windows form testing, since Autohotkey's API allows you to directly reference controls on the Windows form. However Autohotkey does not have similar support for web forms (everything is just one big "InternetExplorer" control). While I would prefer that I could script some variance in the data to help serialize each test, it's not necessary, as I could go back through and manually edit a field or two (plus "break" whatever control I'm currently testing) to serialize each test. If you've ever seen Spawner: http://forge.mysql.com/projects/project.php?id=214 It's almost exactly the sort of thing I'm looking for (Spawner generates dummy SQL data, as opposed to dummy webform data) - but I won't be picky, I've got a really short deadline to meet and had this thrust in my lap just today. ;) Edit1: One of the challenges of just using Autohotkey to simulate keyboard input (tabbing through controls) is that some controls don't currently have tab index (bug), and some controls cause a page reload after modification, resulting in inconsistent control focus (tabbing screwed up). Our application makes heavy use of page reloads to populate fields (select a location, it auto-populates a city, for example).

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  • how is data stored at bit level according to "Endianness" ?

    - by bakra
    I read about Endianness and understood squat... so I wrote this main() { int k = 0xA5B9BF9F; BYTE *b = (BYTE*)&k; //value at *b is 9f b++; //value at *b is BF b++; //value at *b is B9 b++; //value at *b is A5 } k was equal to "A5 B9 BF 9F" and (byte)pointer "walk" o/p was "9F BF b9 A5" so I get it bytes are stored backwards...ok. ~ so now I thought how is it stored at BIT level... I means is "9f"(1001 1111) stored as "f9"(1111 1001)? so I wrote this int _tmain(int argc, _TCHAR* argv[]) { int k = 0xA5B9BF9F; void *ptr = &k; bool temp= TRUE; cout<<"ready or not here I come \n"< for(int i=0;i<32;i++) { temp = *( (bool*)ptr + i ); if( temp ) cout<<"1 "; if( !temp) cout<<"0 "; if(i==7||i==15||i==23) cout<<" - "; } } I get some random output even for nos. like "32" I dont get anything sensible. why ?

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  • What is the best software design to use in this scenario

    - by domdefelice
    I need to generate HTML snippets using jQuery. The creation of those snippets depends on some data. The data is stored server-side, in session (where PHP is used). At the moment I achieved this - retrieving the data from the server via AJAX in form of JSON - and building the snippets via specific javascript functions that read those data The problem is that the complexity of the data is getting bigger and hence the serialization into JSON is getting even more difficult since I can't do it automatically. I can't do it automatically because some information are sensible so I generate a "stripped" version to send to the client. I know it is difficult to understand without any code to read, but I am hoping this is a common scenario and would be glad for any tip, suggestion or even design-pattern you can give me. Should I store both a complete and a stripped data on the server and then use some library to automatically generate the JSON from the stripped data? But this also means I have to get the two data synchronized. Or maybe I could move the logic server-side, this way avoiding sending the data. But this means sending javascript code (since I rely on jQuery). Maybe not a good idea. Feel free to ask me more details if this is not clear. Thank you for any help

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  • Outgoing UDP sniffer in python?

    - by twneale
    I want to figure out whether my computer is somehow causing a UDP flood that is originating from my network. So that's my underlying problem, and what follows is simply my non-network-person attempt to hypothesize a solution using python. I'm extrapolating from recipe 13.1 ("Passing Messages with Socket Datagrams") from the python cookbook (also here). Would it possible/sensible/not insane to try somehow writing an outgoing UDP proxy in python, so that outgoing packets could be logged before being sent on their merry way? If so, how would one go about it? Based on my quick research, perhaps I could start a server process listening on suspect UDP ports and log anything that gets sent, then forward it on, such as: import socket s =socket.socket(socket.AF_INET, socket.SOCK_DGRAM) s.bind(("", MYPORT)) while True: packet = dict(zip('data', 'addr'), s.recvfrom(1,024)) log.info("Recieved {data} from {addr}.".format(**packet)) But what about doing this for a large number of ports simultaneously? Impractical? Are there drawbacks or other reasons not to bother with this? Is there a better way to solve this problem (please be gentle).

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  • Bi-directional view model syncing with "live" collections and properties (MVVM)

    - by Schneider
    I am getting my knickers in a twist recently about View Models (VM). Just like this guy I have come to the conclusion that the collections I need to expose on my VM typically contain a different type to the collections exposed on my business objects. Hence there must be a bi-directional mapping or transformation between these two types. (Just to complicate things, on my project this data is "Live" such that as soon as you change a property it gets transmitted to other computers) I can just about cope with that concept, using a framework like Truss, although I suspect there will be a nasty surprise somewhere within. Not only must objects be transformed but a synchronization between these two collections is required. (Just to complicate things I can think of cases where the VM collection might be a subset or union of business object collections, not simply a 1:1 synchronization). I can see how to do a one-way "live" sync, using a replicating ObservableCollection or something like CLINQ. The problem then becomes: What is the best way to create/delete items? Bi-directinal sync does not seem to be on the cards - I have found no such examples, and the only class that supports anything remotely like that is the ListCollectionView. Would bi-directional sync even be a sensible way to add back into the business object collection? All the samples I have seen never seem to tackle anything this "complex". So my question is: How do you solve this? Is there some technique to update the model collections from the VM? What is the best general approach to this?

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  • Is there a Scheduler/Calendar JS Widget library?

    - by Ravi Chhabra
    I am looking for some JavaScript based component to be used as a course scheduler which would be a cross between Google Calendar and the login time. I do not know if the right term for this is Course Scheduler but I shall describe this in more detail here. Course Scheduler The widget would be used to enter date and times of a course, as an example if I run a programming course 3 days a week on Mon, Tue and Wed every 7:00 am to 9:00am, 2 hours every day from 1st September to 30th November. I could answer various questions and the course data would be displayed in the calendar. It would also allow for non pattern based timings where each week is different from the other week etc. Question So would I end up creating something from scratch? Would it be sensible to use Google Calendar API for this? I did a Google search for some widgets, but I believe I need better keywords, as I could not find anything close to what I am looking for. Any tips? Commercial libraries would also work for me. Thanks.

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  • Java OO design confusion: how to handle actions modified by states modified by actions...

    - by Arvanem
    Hi folks, Given an entity, whose action is potentially modified by states (of the entity and other entities) in turn potentially modified by other actions (of the entity and other entities) , what is the best way to code or design to handle the potential existence of the modifiers? Speaking metaphorically, I am coding a Java application representing a piano. As you know a piano has keys (which, when pressed, emit sound) and pedals (which, when pressed, modify the keys' sounds). My base class structure is as follows: Entity (for keys and pedals) State (this holds each entity's states, e.g. name such as "soft pedal", and boolean "Pressed"), Action (this holds each entity's actions, e.g. play sound when pressed, or modify others sounds). By composition, the Entity class has a copy of each of State and Action inside it. e.g.: public class Entity { State entityState = new State(); Action entityAction = new Action(); Thus I have coded a "C-Sharp" key Entity. When I "press" that entity (set its "Pressed" state to true), its action plays a "C-Sharp" sound and then sets its "Pressed" state to false. At the same time, if the "C-Sharp" key entity is not "tuned", its sound deviates from "C-Sharp". Meanwhile I have coded a "soft pedal" Entity. When that entity is "pressed", no sound plays but its action is to make softer the sound of the "C-Sharp" and other key entities. I have also coded a "sustain pedal" Entity. When that entity is "pressed", no sound plays but its action is to enable reverberation of the sound of the "C-Sharp" and other key entities. Both the "soft" and "sustain pedals" can be pressed at the same time with the result that keys entities become both softened and reverberating. In short, I do not understand how to make this simultaneous series of states and actions modify each other in a sensible OO way. I am wary of coding a massive series of "if" statements or "switches". Thanks in advance for any help or links you can offer.

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  • Should java try blocks be scoped as tightly as possible?

    - by isme
    I've been told that there is some overhead in using the Java try-catch mechanism. So, while it is necessary to put methods that throw checked exception within a try block to handle the possible exception, it is good practice performance-wise to limit the size of the try block to contain only those operations that could throw exceptions. I'm not so sure that this is a sensible conclusion. Consider the two implementations below of a function that processes a specified text file. Even if it is true that the first one incurs some unnecessary overhead, I find it much easier to follow. It is less clear where exactly the exceptions come from just from looking at statements, but the comments clearly show which statements are responsible. The second one is much longer and complicated than the first. In particular, the nice line-reading idiom of the first has to be mangled to fit the readLine call into a try block. What is the best practice for handling exceptions in a funcion where multiple exceptions could be thrown in its definition? This one contains all the processing code within the try block: void processFile(File f) { try { // construction of FileReader can throw FileNotFoundException BufferedReader in = new BufferedReader(new FileReader(f)); // call of readLine can throw IOException String line; while ((line = in.readLine()) != null) { process(line); } } catch (FileNotFoundException ex) { handle(ex); } catch (IOException ex) { handle(ex); } } This one contains only the methods that throw exceptions within try blocks: void processFile(File f) { FileReader reader; try { reader = new FileReader(f); } catch (FileNotFoundException ex) { handle(ex); return; } BufferedReader in = new BufferedReader(reader); String line; while (true) { try { line = in.readLine(); } catch (IOException ex) { handle(ex); break; } if (line == null) { break; } process(line); } }

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  • Return type from DAL class (Sql ce, Linq to Sql)

    - by bretddog
    Hi, Using VS2008 and Sql CE 3.5, and preferably Linq to Sql. I'm learning database, and unsure about DAL methods return types and how/where to map the data over to my business objects: I don't want direct UI binding. A business object class UserData, and a class UserDataList (Inherits List(Of UserData)), is represented in the database by the table "Users". I use SQL Compact and run SqlMetal which creates dbml/designer.vb file. This gives me a class with a TableAttribute: <Table()> _ Partial Public Class Users I'm unsure how to use this class. Should my business object know about this class, such that the DAL can return the type Users, or List(Of Users) ? So for example the "UserDataService Class" is a part of the DAL, and would have for example the functions GetAll and GetById. Will this be correct : ? Public Class UserDataService Public Function GetAll() As List(Of Users) Dim ctx As New MyDB(connection) Dim q As List(Of Users) = From n In ctx.Users Select n Return q End Function Public Function GetById(ByVal id As Integer) As Users Dim ctx As New MyDB(connection) Dim q As Users = (From n In ctx.Users Where n.UserID = id Select n).Single Return q End Function And then, would I perhaps have a method, say in the UserDataList class, like: Public Class UserDataList Inherits List(Of UserData) Public Sub LoadFromDatabase() Me.clear() Dim database as New UserDataService dim users as List(Of Users) users = database.GetAll() For each u in users dim newUser as new UserData newUser.Id = u.Id newUser.Name = u.Name Me.Add(newUser) Next End Sub End Class Is this a sensible approach? Would appreciate any suggestions/alternatives, as this is my first attempt on a database DAL. cheers!

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  • What Do You Need To Write Your Own Blog Engine?

    - by deworde
    I've been messing around with basic websites for a few years, using companies like www.Fasthosts.co.uk to do my web hosting. But I'd like to expand my skills from C++ and Java app programming into Web-based programming, and I think the best way to do that is with a project. I've chosen to go with a blog engine because it's a relative comprehensive yet non-complex project. I'm aware that you can just go to Blogger and bam! One blog. I've done that, so that I can at least have some content, and work out what I want to do with this blog. At the moment, I'm thinking I'll use it to chart my progress creating the blogging engine. But I have some questions. Do you need to be running your own server? Or is it more sensible in the short-term to use a hosting company? What types of language are worth considering? What's important to focus on from a design perspective? What unexpected problems might I encounter?

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  • Show users a list of unique items on Java Google App Engine

    - by James
    I've been going round in circles with what must be a very simple challenge but I want to do it the most efficient way from the start. So, I've watched Brett Slatkin's Google IO videos (2008 & 2009) about building scalable apps including http://www.youtube.com/watch?v=AgaL6NGpkB8 and read the docs but as a n00b, I'm still not sure. I'm trying to build an app on GAEJ similar to the original 'hotornot' where a user is presented with an item which they rate. Once they rate it, they are presented with another one which they haven't seen before. My question is this; is it most efficient to do a query up front to grab x items (say 100) and put them in a list (stored in memcache?) or is it better to simply make a query for a new item after each rating. To keep track of the items a user has seen, I'm planning to keep those items' keys in a list property of the user's entity. Does that sound sensible? I've really got myself confused about this so any help would be much appreciated.

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  • Qt cross thread call

    - by QLatvia
    I have a Qt/C++ application, with the usual GUI thread, and a network thread. The network thread is using an external library, which has its own select() based event loop... so the network thread isn't using Qt's event system. At the moment, the network thread just emit()s signals when various events occur, such as a successful connection. I think this works okay, as the signals/slots mechanism posts the signals correctly for the GUI thread. Now, I need for the network thread to be able to call the GUI thread to ask questions. For example, the network thread may require the GUI thread to request put up a dialog, to request a password. Does anyone know a suitable mechanism for doing this? My current best idea is to have the network thread wait using a QWaitCondition, after emitting an object (emit passwordRequestedEvent(passwordRequest);. The passwordRequest object would have a handle on the particular QWaitCondition, and so can signal it when a decision has been made.. Is this sort of thing sensible? or is there another option?

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