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  • Switch between multiple views while respecting orientation

    - by zoul
    Hello! I have an MVC application with a single model and several views (something like skins). I want the user to be able to switch the views and I can’t get it working with interface orientation. The most simple approach looks like this: - (void) switchToADifferentView: (UIView*) newView { // self is a descendant of UIViewController self.view = newView; } This does not work because the incoming view does not get rotated according to current orientation (until the next orientation change, test case). Is there a way to force the orientation on a view? It looks like the system is trying really hard to keep the interface controls for itself. (Or is it as simple as setting the right transform by hand?) I figured I’d better not switch the views directly and switch controllers instead. This makes sense, as it makes the initial code simpler. But how do I switch controllers that have no “navigation relation” between them? I guess I could use presentModalViewController:, but that seems like a hack. Same goes for navigation controller. If I exchange the controllers by hand, I get the wrong orientation again: - (void) switchToAController: (id) incoming { [currentController.view removeFromSuperview]; [window addSubview:incoming.view]; // does not respect current orientation } Now how the heck do I simply exchange the current controller for another one? Again, the controllers are something like “skins” operating above a shared model, so it really makes no sense to pretend that skin A is a “modal” dialog above skin B or that they’re a part of a navigation stack.

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  • Are there scenarios where the ViewModel needs to invoke methods on the View w.r.t. MVVM in WPF?

    - by Gishu
    As per the pattern, the ViewModel exposes Properties(with change notification) and Commands (to notify the VM of user actions) that the View binds to. The only communication that flows from the VM to the View is the property change notifications (so that the View can refresh itself with updated data). In MVP or PresentationModel form of the pattern (if I'm not mistaken), the View implements a plain vanilla interface (consisting of methods, properties and/or events). With MVVM, it feels methods on the IView have been outlawed (along with IView itself). One scenario I could think of was to set the focus to a certain control in the View. (When the user does ActionX, the focus should immediately be set to FieldY). In MVP, I'd write this as IView.ActivateField(NameConstant), which the presenter or PM would invoke. In MVVM, this seems to be a fringe case that needs a workaround / little bit of code-behind. The VM implements an ActiveField Property, which it sets to NameConstant. The view picks up the change notification event and in a code-behind event handler, activates the Name control. Is the above just an exception to the norm? Or are there other such scenarios, where the VM needs to invoke a method on the View ?

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  • Inserting a ContentControl after another ContentControl

    - by Markus Roth
    In our VSTO Word 2010 Addin, we are trying to insert a RichTextControl after a given other ContentControl. We have tried this: public ContentControl AddContentControl(WdContentControlType type, int position) { Paragraph paragraphBefore = null; if (position == 0) { if (WordDocument.Paragraphs.Count == 0) { WordDocument.Paragraphs.Add(); } paragraphBefore = WordDocument.Paragraphs.First; } else { paragraphBefore = Controls.ElementAt(position - 1).Range.Paragraphs.Last; } object start = paragraphBefore.Range.End; object end = paragraphBefore.Range.End + 1; paragraphBefore.Range.InsertParagraphAfter(); Range rangeToUse = WordDocument.Range(ref start, ref end); ContentControl newControl = _ContentControl = _WordDocument.ContentControls.Add(type, rangeToInsert); Controls.Insert(position, newControl); OnNewContentControl(newControl, position); return newControl.ContentControl; } which works fine, unless the control that is before the one we want to insert has an empty paragraph at the end. If that is the case, the new ContentControl is inserted within the last control. How can we avoid this?

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  • Using custom coordinates with QGraphicsScene

    - by Rob
    I am experimenting with a WYSIWYG editor that allows a user to draw shapes on a page and the Qt graphics scene support seems perfect for this. However, instead of working in pixels I want all my QGraphicsItem objects to work in tenths of a millimetre but I don't know how to achieve this. For example: // Create a scene that is the size if an A4 page (2100 = 21cm, 2970 = 29.7cm) QGraphicsScene* scene = new QGraphicsScene(0, 0, 2100, 2970); // Add a rectangle located 1cm across, 1cm down, 5cm wide and 2cm high QGraphicsItem* item = scene->addRect(100, 100, 500, 200); ... QGraphicsView* view = new QGraphicsView(scene); setCentralWidget(view); Now, when I display the scene above I want the shapes to appear at correct size for the screen DPI. Is this simply a case of using QGraphicsView::scale or do I have to do something more complicated? Note that if I was using a custom QWidget instead then I would use QPainter::setWindow and QPainter::setViewport to create a custom mapping mode but I can't see how to do this using the graphics scene support.

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  • Calling a SLSB with Seam security from a servlet

    - by wilth
    Hello, I have an existing application written in SEAM that uses SEAM Security (http://docs.jboss.org/seam/2.1.1.GA/reference/en-US/html/security.html). In a stateless EJB, I might find something like this: @In Identity identity; ... if(identity.hasRole("admin")) throw new AuthException(); As far as I understand, Seam injects the Identity object from the SessionContext of the servlet that invokes the EJB (this happens "behind the scenes", since Seam doesn't really use servlets) and removes it after the call. Is this correct? Is it now possible to access this EJB from another servlet (in this case, that servlet is the server side of a GWT application)? Do I have to "inject" the correct Identity instance? If I don't do anything, Seam injects an instance, but doesn't correctly correlate the sessions and instances of Identity (so the instances of Identity are shared between sessions and sometimes calls get new instances etc.). Any help and pointers are very welcome - thanks! Technology: EJB3, Seam 2.1.2. The servlets are actually the server-side of a GWT app, although I don't think this matters much. I'm using JBoss 5.

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  • Join + IEqualityComparer<T> and HashCode

    - by Jesus Rodriguez
    Im writing my own LINQ reference but Im getting troubles with some of the more complicated operators implementations. There is a Join implementation that takes a IEqualityComparer Im getting just crazy. Im trying to understand it first before I write (obviously) Image this two lists: List<string> initials = new List<string> {"A", "B", "C", "D", "E"}; List<string> words = new List<string> {"Ant", "Crawl", "Pig", "Boat", "Elephant", "Arc"}; Nothing weird here. I want to join both lists by the Initial, something like: Initial=A Word=Ant Initial=A Word=Arc Initial=B Word=Boat ... I need a comparator, I wrote this: public class InitialComparator : IEqualityComparer<string> { public bool Equals(string x, string y) { return x.StartsWith(y); } public int GetHashCode(string obj) { return obj[0].GetHashCode(); } } The Join itself: var blah = initials.Join(words, initial => initial, word => word, (initial, word) => new {Initial = initial, Word = word}, new InitialComparator()); It's the first time Im using HashCodes, after a good session of debugging I see that every word go to the comparator and look at its HashCode, if another word has the same HashCode it calls equals. Since I want to compare just the initial I though that I just need the first letter Hash (Am I wrong?) The thing is that this is not working correctly. Its says that "Ant" and "Arc" are equals, Ok, its comparing every word in the same list or not, But it adds only the last word it finds, in this case Arc, ignoring Ant and Ant is equals to "A" too... If I put "Ant" and "Ant" it add both. In short, What is the way of doing something like that? I know that Im doing something wrong. Thank you.

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  • auto m3u creation

    - by newbie69
    Hi, I am looking for a solution to automatically create .m3u playlists for each music folder in my sdcard so that the music player can play music by folders. I had written a simple VB.Net app in the past that does exactly the above but apparently, it has to be run from Windows. Since I have no Java nor Android developing experience I found it quite hard to try to write a similar app that can be run directly from the phone. In a few words, the app does the following: 1) Searches the SD and lists all folders that contain 2 or more .mp3 files (just for user verification) 2) Creates in every listed folder above, a .m3u file that simply lists line-by-line all the mp3 files that exist in the specific folder. Is there such an app or could someone spare some time and give me some rough instructions on how to create it in Eclipse 3.5.2 environment? (device used: Motorola Droid/Milestone, Android 2.1) I don't care about any graphics or complex UI, just a script to execute the above procedure that would give every "playlist-supporting" music player in Android, the precious ability to play music by folders. I know it is too much to ask but just in case! Thanx in advance.

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  • Choosing between .NET Service Bus Queues vs Azure Queue Service

    - by ChrisV
    Just a quick question regarding an Azure application. If I have a number of Web and Worker roles that need to communicate, documentation says to use the Azure Queue Service. However, I've just read that the new .NET Service Bus now also offers queues. These look to be more powerful as they appear to offer a much more detailed API. Whilst the .NSB looks more interesting it has a couple of issues that make me wary of using it in distributed application. (for example, Queue Expiration... if I cannot guarantee that a queue will be renewed on time I may lose it all!). Has anyone had any experience using either of these two technologies and could give any advice on when to choose one over the other. I suspect that whilst the service bus looks more powerful, as my use case is really just enabling Web/Worker roles to communicate between each other, that the Azure Queue Service is what I'm after. But I'm just really looking for confirmation of that before progamming myself in to a corner :-) Thanks in advance. UPDATE Have read up about the two systems over the break. It defo looks like .NET service bus is more specifically designed for integrating systems rather than providing a general purpose reliable messaging system. Azure Queues are distributed and so reliable and scalable in a way that .NSB queues are not and so more suitable for code hosted within Azure itself. Thanks for the responses.

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  • Rails 3 get raw post data and write it to tmp file

    - by Andrew
    I'm working on implementing Ajax-Upload for uploading photos in my Rails 3 app. The documentation says: For IE6-8, Opera, older versions of other browsers you get the file as you normally do with regular form-base uploads. For browsers which upload file with progress bar, you will need to get the raw post data and write it to the file. So, how can I receive the raw post data in my controller and write it to a tmp file so my controller can then process it? (In my case the controller is doing some image manipulation and saving to S3.) Some additional info: As I'm configured right now the post is passing these parameters: Parameters: {"authenticity_token"=>"...", "qqfile"=>"IMG_0064.jpg"} ... and the CREATE action looks like this: def create @attachment = Attachment.new @attachment.user = current_user @attachment.file = params[:qqfile] if @attachment.save! respond_to do |format| format.js { render :text => '{"success":true}' } end end end ... but I get this error: ActiveRecord::RecordInvalid (Validation failed: File file name must be set.): app/controllers/attachments_controller.rb:7:in `create'

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  • How to modify/replace option set file when building from command line?

    - by Heinrich Ulbricht
    I build packages from a batch file using commands like: msbuild ..\lib\Package.dproj /target:Build /p:config=%1 The packages' settings are dependent on an option set: <Import Project="..\optionsets\COND_Defined.optset" Condition="'$(Base)'!='' And Exists('..\optionsets\COND_Defined.optset')"/> This option set defines a conditional symbol many of my packages depend on. The file looks like this: <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003"> <PropertyGroup> <DCC_Define>CONDITION;$(DCC_Define)</DCC_Define> </PropertyGroup> <ProjectExtensions> <Borland.Personality>Delphi.Personality.12</Borland.Personality> <Borland.ProjectType>OptionSet</Borland.ProjectType> <BorlandProject> <Delphi.Personality/> </BorlandProject> <ProjectFileVersion>12</ProjectFileVersion> </ProjectExtensions> </Project> Now I need two builds: one with the condition defined and one without. My attack vector would be the option set file. I have some ideas on what to do: write a program which modifies the option set file, run this before batch build fiddle with the project files and modify the option set path to contain an environment variable, then have different option sets in different locations But before starting to reinvent the wheel I'd like to ask how you would tackle this task? Maybe there are already means meant to support such a case (like certain command line switches, things I could configure in Delphi or batch file magic).

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  • How to configure database connection securely

    - by chiccodoro
    Similar but not the same: How to securely store database connection details Securely connecting to database within a application Hi all, I have a C# WinForms application connecting to a database server. The database connection string, including a generic user/pass, is placed in a NHibernate configuration file, which lies in the same directory as the exe file. Now I have this issue: The user that runs the application should not get to know the username/password of the general database user because I don't want him to rummage around in the database directly. Alternatively I could hardcode the connection string, which is bad because the administrator must be able to change it if the database is moved or if he wants to switch between dev/test/prod environments. So long I've found three possibilities: The first referenced question was generally answered by making the file only readable for the user that runs the application. But that's not not enough in my case (the user running the application is a person. The database user/pass are general and shouldn't even be accessible by the person.) The first answer additionally proposed to encrypt the connection data before writing it to the file. With this approach, the administrator is not able anymore to configure the connection string because he cannot encrypt it by hand. The second referenced question provides an approach for this very scenario but it seems very complicated. My questions to you: This is a very general issue, so isn't there any general "how-to-do-it" way, somehow a "design pattern"? Is there some support in .NET's config infrastructure? (optional, maybe out of scope) Can I combine that easily with the NHibernate configuration mechanism?

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  • Flex wordwrap issue with multiple text instances

    - by Craig Myles
    Hi, I have a scenario where I want to dynamically add words of text to a container so that it forms a paragraph of text which is wrapped neatly according to the size of the parent container. Each text element will have differing formatting, and will have differing user interaction options. For example, imagine the text " has just spoken out about ". Each word will be added to the container one at a time, at run time. The username in this case would be bold, and if clicked on will trigger an event. Same with the news article. The rest of the text is just plain text which, when clicked on, would do nothing. Now, I'm using Flex 3 so I don't have access to the fancy new text formatting tools. I've implemented a solution where the words are plotted onto a canvas, but this means that the words are wrapped at a particular y position (an arbitrary value I've chosen). When the container is resized, the words still wrap at that position which leaves lots of space. I thought about adding each text element to an Array Collection and using this as a datasource for a Tile List, but Tile Lists don't support variable column widths (in my limited knowledge) so each word would use the same amount of space which isn't ideal. Does anyone know how I can plot words onto a container so that I can retain formatting, events and word wrapping at paragraph level, even if the container is resized?

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  • How to send a JSONObject to a REST service?

    - by Sebi
    Retrieving data from the REST Server works well, but if I want to post an object it doesn't work: public static void postJSONObject(int store_type, FavoriteItem favorite, String token, String objectName) { String url = ""; switch(store_type) { case STORE_PROJECT: url = URL_STORE_PROJECT_PART1 + token + URL_STORE_PROJECT_PART2; //data = favorite.getAsJSONObject(); break; } HttpClient httpClient = new DefaultHttpClient(); HttpPost postMethod = new HttpPost(url); try { HttpEntity entity = new StringEntity("{\"ID\":0,\"Name\":\"Mein Projekt10\"}"); postMethod.setEntity(entity); HttpResponse response = httpClient.execute(postMethod); Log.i("JSONStore", "Post request, to URL: " + url); System.out.println("Status code: " + response.getStatusLine().getStatusCode()); } catch (ClientProtocolException e) { I always get a 400 Error Code. Does anybody know whats wrong? I have working C# code, but I can't convert: System.Net.WebRequest wr = System.Net.HttpWebRequest.Create("http://localhost:51273/WSUser.svc/pak3omxtEuLrzHSUSbQP/project"); wr.Method = "POST"; string data = "{\"ID\":1,\"Name\":\"Mein Projekt\"}"; byte [] d = UTF8Encoding.UTF8.GetBytes(data); wr.ContentLength = d.Length; wr.ContentType = "application/json"; wr.GetRequestStream().Write(d, 0, d.Length); System.Net.WebResponse wresp = wr.GetResponse(); System.IO.StreamReader sr = new System.IO.StreamReader(wresp.GetResponseStream()); string line = sr.ReadToEnd();

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  • How to make a mapped field inherited from a superclass transient in JPA?

    - by Russ Hayward
    I have a legacy schema that cannot be changed. I am using a base class for the common features and it contains an embedded object. There is a field that is normally mapped in the embedded object that needs to be in the persistence id for only one (of many) subclasses. I have made a new id class that includes it but then I get the error that the field is mapped twice. Here is some example code that is much simplified to maintain the sanity of the reader: @MappedSuperclass class BaseClass { @Embedded private Data data; } @Entity class SubClass extends BaseClass { @EmbeddedId private SubClassId id; } @Embeddable class Data { private int location; private String name; } @Embeddable class SubClassId { private int thingy; private int location; } I have tried @AttributeOverride but I can only get it to rename the field. I have tried to set it to updatable = false, insertable = false but this did not seem to work when used in the @AttributeOverride annotation. See answer below for the solution to this issue. I realise I could change the base class but I really do not want to split up the embedded object to separate the shared field as it would make the surrounding code more complex and require some ugly wrapping code. I could also redesign the whole system for this corner case but I would really rather not. I am using Hibernate as my JPA provider.

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  • Maven Mojo & SCM Plugin: Check for a valid working directory

    - by Patrick Bergner
    Hi there. I'm using maven-scm-plugin from within a Mojo and am trying to figure out how to determine if a directory D is a valid working directory of an SCM URL U (i.e. a checkout of U to D already happened). The context is that I want to do a checkout of U if D is a working set or do an update if it isn't. The plan is to check out U to D if D does not exist, update D if D is a valid working directory of U, display an error if D exists and is not a valid working directory of U. What I tried is to call ScmManager.status(), ScmManager.list() and ScmManager.changelog() and try to guess something from their results. But that didn't work. The results from status and changelog always return something positive (isSuccess() = true, getChangedFiles() = valid List, no exceptions to catch), whereas list throws an exception in any case. ScmRepository and ScmFileSet don't seem to provide suitable methods as well. An option would be to always do an update if D exists but then I cannot tell if it is a working directory of U or any SCM working directory at all. The ideal solution would be independent of the actual SCM system and a specific ScmVersion. Thanks for your help! Patrick

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  • HTTP POST prarameters order / REST urls

    - by pq
    Let's say that I'm uploading a large file via a POST HTTP request. Let's also say that I have another parameter (other than the file) that names the resource which the file is updating. The resource cannot be not part of the URL the way you can do it with REST (e.g. foo.com/bar/123). Let's say this is due to a combination of technical and political reasons. The server needs to ignore the file if the resource name is invalid or, say, the IP address and/or the logged in user are not authorized to update the resource. Looks like, if this POST came from an HTML form that contains the resource name first and file field second, for most (all?) browsers, this order is preserved in the POST request. But it would be naive to fully rely on that, no? In other words the order of HTTP parameters is insignificant and a client is free to construct the POST in any order. Isn't that true? Which means that, at least in theory, the server may end up storing the whole large file before it can deny the request. It seems to me that this is a clear case where RESTful urls have an advantage, since you don't have to look at the POST content to perform certain authorization/error checking on the request. Do you agree? What are your thoughts, experiences?

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  • Query on object id in VQL

    - by Banang
    I'm currently working with the versant object database (using jvi), and have a case where I need to query the database based on an object id. What I'm trying to achieve is something along the lines of Employee employee = new Employee("Mr. Pickles"); session.commit(); FundVQLQuery q = new FundVQLQuery(session, "select * from Employee employee where employee = $1"); q.bind(employee); q.execute(); However, I'm finding out the hard way (I get an EVJ_NOT_A_VALID_KEY_TYPE error thrown at me) that this is infact not the way to do it. Anyone got any experience in working with VQL? Your help is much apreciated! A small clarification: The problem is I'm running some performance tests on the database using the pole position framework, and one of the tests in that framework requires me to fetch an object from the database using either an object reference or a low level object id. Thus, I'm not allowed to reference specific fields in the employee object, but must perform the query on the object in its entirety. So, it's not allowed for me to go "select * from Employee e where e.id = 4", I need it to use the entire object. Accepted answer: Since there is some sort of lunacy magic built into SO that prevents me to mark an accepted answer after a bounty has run out, readers should know that the answer posted by Chris Holmes solves this issue. Readers are encouraged to up-vote his post to further signalize the correctness of his answer to any future readers of this thread.

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  • Adaptive user interface/environment algorithm

    - by WowtaH
    Hi all, I'm working on an information system (in C#) that (while my users use it) gathers statistical data on what pieces of information (tables & records) each user is requesting the most, and what parts of the interface he/she uses most. I'm using this statistical data to make the application adaptive to the user's needs, both in the way the interface presents itself (eg: tab/pane-ordering) as in the way of using the frequently viewed information to (eg:) show higher in search results/suggestion-lists. What i'm looking for is an algorithm/formula to determine the current 'hotness'/relevance of these objects for a specific user. A simple 'hitcounter' for each object won't be sufficient because the user might view some information quite frequently for a period of time, and then moving on to the next, making the old information less relevant. So i think my algorithm also needs some sort of sliding/historical principle to account for the changing popularity of the objects in the application over time. So, the question is: Does anybody have some sort of algorithm that accounts for that 'popularity over time' ? Preferably with some explanation on the parameters :) Thanks! PS I've looked at other posts like http://stackoverflow.com/questions/32397/popularity-algorithm but i could't quite port it to my specific case. Any help is appreciated.

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  • Combo box in a scrollable panel causing problems

    - by Dennis
    I have a panel with AutoScroll set to true. In it, I am programmatically adding ComboBox controls. If I add enough controls to exceed the viewable size of the panel a scroll bar appears (so far so good). However, if I open one of the combo boxes near the bottom of the viewable area the combo list isn't properly displayed and the scrollable area seems to be expanded. This results in all of the controls being "pulled" to the new bottom of the panel with some new blank space at the top. If I continue to tap on the drop down at the bottom of the panel the scrollable area will continue to expand indefinitely. I'm anchoring the controls to the left, right and top so I don't think anchoring is involved. Is there something obvious that could be causing this? Update: It looks like the problem lies with anchoring the controls to the right. If I don't anchor to the right then I don't get the strange behavior. However, without right anchoring the control gets cut off by the scroll bar. Here's a simplified test case I built that shows the issue: public Form1() { InitializeComponent(); Panel panel = new Panel(); panel.Size = new Size(80, 200); panel.AutoScroll = true; for (int i = 0; i < 10; ++i) { ComboBox cb = new ComboBox(); cb.Anchor = AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Top; cb.Items.Add("Option 1"); cb.Items.Add("Option 2"); cb.Items.Add("Option 3"); cb.Items.Add("Option 4"); cb.Location = new Point(0, i * 24); panel.Controls.Add(cb); } Controls.Add(panel); } If you scroll the bottom of the panel and tap on the combo boxes near the bottom you'll notice the strange behavior.

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  • jQuery: list appended not displaying bullets

    - by Shizhidi
    I have the following html: <!DOCTYPE html> <html> <head> <script src="http://code.jquery.com/jquery-latest.js"></script> </head> <body> <span>not so important</span> <span title="some specific text"><img src="/img/some.gif" /></span> <span title="more specific text">important 1</span> <span title="more specific text">important 2</span> <span title="more specific text">important 3</span> <span title="more specific text"><img src="/img/some.gif" /></span> <ul> <li>example 1</li> <li>example 2</li> <li>example 3</li> <ul> <script> var ul = $('body').append($('<ul>')); $("span[title*='specific text']") .contents() .filter(function(){ return $(this).nodeType != 1; }) .each(function(){ ul.append($('<li>' + $(this).text() + '</li>')); }) </script> </body> </html> I want to retrieve the text within a 'span' whose title attribute contains "specific text", in this case "important 1", "important 2" and "important 3". Then I want to list them below just like the example. However the bullets do not appear, why is that? Any hints would be appreciated!

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  • Most unintuitive behaviour in the .Net framework?

    - by BlueRaja
    Intended behavior is often another phrase for bug-which-we-knew-about-when-we-wrote-it, but-we-wrote-it-anyways. Because it was "intended" (or perhaps it is now too late or too difficult), many of these extremely-unintuitive bugs never get fixed. For instance, consider the following code (C#): TextInfo textInfo = Thread.CurrentThread.CurrentCulture.TextInfo; textInfo.ToTitleCase("hello world!"); //Returns "Hello World!" textInfo.ToTitleCase("hElLo WoRld!"); //Returns "Hello World!" textInfo.ToTitleCase("Hello World!"); //Returns "Hello World!" What would you expect textInfo.ToTitleCase("HELLO WORLD!"); to return? In fact, it returns "HELLO WORLD!". This was well-documented "intended behavior," but, in my eyes, is extremely unintuitive, and therefore a bug. What is some other unintuitive behavior like this in this in the .Net framework? Bonus points if you can provide a fix that does not break backwards-compatibility. Remember! Always keep these two simple rules in mind when designing an API (or anything else): Make the common case the default, and Keep It Simple, Stupid!

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  • Best Practice - Removing item from generic collection in C#

    - by Matt Davis
    I'm using C# in Visual Studio 2008 with .NET 3.5. I have a generic dictionary that maps types of events to a generic list of subscribers. A subscriber can be subscribed to more than one event. private static Dictionary<EventType, List<ISubscriber>> _subscriptions; To remove a subscriber from the subscription list, I can use either of these two options. Option 1: ISubscriber subscriber; // defined elsewhere foreach (EventType event in _subscriptions.Keys) { if (_subscriptions[event].Contains(subscriber)) { _subscriptions[event].Remove(subscriber); } } Option 2: ISubscriber subscriber; // defined elsewhere foreach (EventType event in _subscriptions.Keys) { _subscriptions[event].Remove(subscriber); } I have two questions. First, notice that Option 1 checks for existence before removing the item, while Option 2 uses a brute force removal since Remove() does not throw an exception. Of these two, which is the preferred, "best-practice" way to do this? Second, is there another, "cleaner," more elegant way to do this, perhaps with a lambda expression or using a LINQ extension? I'm still getting acclimated to these two features. Thanks. EDIT Just to clarify, I realize that the choice between Options 1 and 2 is a choice of speed (Option 2) versus maintainability (Option 1). In this particular case, I'm not necessarily trying to optimize the code, although that is certainly a worthy consideration. What I'm trying to understand is if there is a generally well-established practice for doing this. If not, which option would you use in your own code?

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  • twisted deferred/callbacks and asynchronous execution

    - by NetSkay
    hey guys, quick question about twisted and python... im trying to figure out how can i make my code more asynchronous using twisted and ive come to sort of a dead end, if a function of mine returns a deferred object, then i add a list of callbacks, the first callback will be called after the deferred function provides some result through deferred_obj.callback, then, in the chain of callbacks, the first callback will do something with the data and call the second callback and etc. however chained callbacks will not be considered asynchronous because they're chained and the event loop will keep firing each one of them concurrently until there is no more, right? however, if i have a deferred object, and i attach as its callback the deferred_obj.callback as in d.addCallback(deferred_obj.callback) then this will be considered asynchronous, because the deferred_obj is waiting for the data, and then the method that will pass the data is waiting on data as well, however once i d.callback 'd' object processes the data then it call deferred_obj.callback however since this object is deferred, unlike the case of chained callbacks, it will execute asynchronously... correct? meaning chained callbacks are NOT asynchronous while chained deferreds are, correct? thank you PS: assuming all of my code is non-blocking

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  • Destructuring assignment in JavaScript

    - by Anders Rune Jensen
    As can be seen in the Mozilla changlog for JavaScript 1.7 they have added destructuring assignment. Sadly I'm not very fond of the syntax (why write a and b twice?): var a, b; [a, b] = f(); Something like this would have been a lot better: var [a, b] = f(); That would still be backwards compatible. Python-like destructuring would not be backwards compatible. Anyway the best solution for JavaScript 1.5 that I have been able to come up with is: function assign(array, map) { var o = Object(); var i = 0; $.each(map, function(e, _) { o[e] = array[i++]; }); return o; } Which works like: var array = [1,2]; var _ = assign[array, { var1: null, var2: null }); _.var1; // prints 1 _.var2; // prints 2 But this really sucks because _ has no meaning. It's just an empty shell to store the names. But sadly it's needed because JavaScript doesn't have pointers. On the plus side you can assign default values in the case the values are not matched. Also note that this solution doesn't try to slice the array. So you can't do something like {first: 0, rest: 0}. But that could easily be done, if one wanted that behavior. What is a better solution?

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  • Using Pylint with Django

    - by rcreswick
    I would very much like to integrate pylint into the build process for my python projects, but I have run into one show-stopper: One of the error types that I find extremely useful--:E1101: *%s %r has no %r member*--constantly reports errors when using common django fields, for example: E1101:125:get_user_tags: Class 'Tag' has no 'objects' member which is caused by this code: def get_user_tags(username): """ Gets all the tags that username has used. Returns a query set. """ return Tag.objects.filter( ## This line triggers the error. tagownership__users__username__exact=username).distinct() # Here is the Tag class, models.Model is provided by Django: class Tag(models.Model): """ Model for user-defined strings that help categorize Events on on a per-user basis. """ name = models.CharField(max_length=500, null=False, unique=True) def __unicode__(self): return self.name How can I tune Pylint to properly take fields such as objects into account? (I've also looked into the Django source, and I have been unable to find the implementation of objects, so I suspect it is not "just" a class field. On the other hand, I'm fairly new to python, so I may very well have overlooked something.) Edit: The only way I've found to tell pylint to not warn about these warnings is by blocking all errors of the type (E1101) which is not an acceptable solution, since that is (in my opinion) an extremely useful error. If there is another way, without augmenting the pylint source, please point me to specifics :) See here for a summary of the problems I've had with pychecker and pyflakes -- they've proven to be far to unstable for general use. (In pychecker's case, the crashes originated in the pychecker code -- not source it was loading/invoking.)

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