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  • Graphic card for parallel programming vs traditional methods

    - by Sambatyon
    With a simple search in amazon one can see that the modern approach for parallel programming is to use your graphic card. However I am still a little bit skeptical about it. My last computer has an 8 core CPU which I need is enough for basic all my parallel needs, if I need more I will probably use MPI through a network using my old machines. All in all, Why and/or when should I use CUDA or another method which uses my graphic card instead of traditional methods like pthreads, java threads, boost threads or the new C++ 11 threads? What about using processes?

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  • Java - What methods to put in an interface and what to keep out

    - by lewicki
    I'm designing a file handler interface: public interface FileHandler { public void openFileHandler(String fileName); public void closeFileHandler(); public String readLine(); public String [] parseLine(String line); public String [] checkLine(String line[]); public void incrementLineCount(); public void incrementLineSuccessCount(); public void incrementLineErrorCount(); public int getLineCount(); public int getLineSuccessCount(); public int getLineErrorCount(); } It is soon apparent to me that these methods can't be made private. I don't want incrementLineCount to be public. What is proper way to design an interface like this?

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  • Problem with Update(GameTime) Methods and Pause implementation

    - by Adam
    I have the pause function implemented and it works correctly in that it dims the player screen and stops updating the gameplay. The problem is that GameTime continues to increase while it is paused, so my method that checks gameTime versus previousSpawnTime before spawning another enemy gets messed up and if the game is paused too long it is noticeable that the next enemy draws far too early. Here is my code for the enemy update. private void UpdateEnemies(GameTime gameTime) { // Spawn a new enemy every 1.5 seconds if (gameTime.TotalGameTime - previousSpawnTime > enemySpawnTime) { previousSpawnTime = gameTime.TotalGameTime; // Add an Enemy AddEnemy(); } ... I also have other methods that depend on gameTime. I've tried getting the total pause time and subtracting that from the total game time, but I can't seem to get it to work correctly if that is the way I should go about solving this. If you need to see any other code let me know. Thank you.

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  • deny-uncovered-http-methods in Servlet 3.1

    - by reza_rahman
    Servlet 3.1 is a relatively minor release included in Java EE 7. However, the Java EE foundational API still contains some very important changes. One such set of features are the security enhancements done in Servlet 3.1 such as the new deny-uncovered-http-methods option. Servlet 3.1 co-spec lead Shing Wai Chan outlines the use case for the feature and shows you how to use it in a recent code example driven post. You can also check out the official specification yourself or try things out with the newly released Java EE 7 SDK.

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  • Should HTTP Verbs Be Used Semantically?

    - by Xophmeister
    If I'm making a web application which integrates with a server-side backend, would it be considered best practice to use HTTP methods semantically? That is, for example, if I'm fetching data (e.g., to populate a menu, etc.), I would use GET, but to update data (e.g., save a record), I would use POST. (I realise there are other methods that may be even more appropriate, but we need to consider browser support.) I can see the benefits of this in the sense that it's effectively a RESTful API, but at a slightly increased development cost. In my previous projects, I've POST'd everything: Is it worth switching to a RESTful mindset simply for the sake of best practice?

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  • The future of programming, or what lies in the future in programming?

    - by prosseek
    I remember that a article that Microsoft uses formal verification to debug the Device Driver, and I also remember that Functional Programming removes much of the bug as it ensures stateless programming. And we all know about the multi-core. I beleive all of them are future direction of programming or programming language. Multi-core programming or parallel programming Software Formal Verification Functional Programming (as a mainstream?) What do you think? What will be the future of programming?

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  • Abstract Methods in "Product" - Factory Method C#

    - by Regina Foo
    I have a simple class library (COM+ service) written in C# to consume 5 web services: Add, Minus, Divide, Multiply and Compare. I've created the abstract product and abstract factory classes. The abstract product named WS's code: public abstract class WS { public abstract double Calculate(double a, double b); public abstract string Compare(double a, double b); } As you see, when one of the subclasses inherits WS, both methods must be overridden which might not be useful in some subclasses. E.g. Compare doesn't need Calculate() method. To instantiate a new CompareWS object, the client class will call the CreateWS() method which returns a WS object type. public class CompareWSFactory : WSFactory { public override WS CreateWS() { return new CompareWS(); } } But if Compare() is not defined as abstract in WS, the Compare() method cannot be invoked. This is only an example with two methods, but what if there are more methods? Is it stupid to define all the methods as abstract in the WS class? My question is: I want to define abstract methods that are common to all subclasses of WS whereas when the factory creates a WS object type, all the methods of the subclasses can be invoked (overridden methods of WS and also the methods in subclasses). How should I do this?

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  • Creation of Objects: Constructors or Static Factory Methods

    - by Rachel
    I am going through Effective Java and some of my things which I consider as standard are not suggested by the book, for instance creation of object, I was under the impression that constructors are the best way of doing it and books says we should make use of static factory methods, I am not able to few some advantages and so disadvantages and so am asking this question, here are the benefits of using it. Advantages: One advantage of static factory methods is that, unlike constructors, they have names. A second advantage of static factory methods is that, unlike constructors, they are not required to create a new object each time they’re invoked. A third advantage of static factory methods is that, unlike constructors, they can return an object of any subtype of their return type. A fourth advantage of static factory methods is that they reduce the verbosity of creating parameterized type instances. I am not able to understand this advantage and would appreciate if someone can explain this point Disadvantages: The main disadvantage of providing only static factory methods is that classes without public or protected constructors cannot be subclassed. A second disadvantage of static factory methods is that they are not readily distinguishable from other static methods.I am not getting this point and so would really appreciate some explanation. Reference: Effective Java, Joshua Bloch, Edition 2, pg: 5-10 Also, How to decide to use whether to go for Constructor or Static Factory Method for Object Creation ?

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  • F#: Advantages of converting top-level functions to member methods?

    - by J Cooper
    Earlier I requested some feedback on my first F# project. Before closing the question because the scope was too large, someone was kind enough to look it over and leave some feedback. One of the things they mentioned was pointing out that I had a number of regular functions that could be converted to be methods on my datatypes. Dutifully I went through changing things like let getDecisions hand = let (/=/) card1 card2 = matchValue card1 = matchValue card2 let canSplit() = let isPair() = match hand.Cards with | card1 :: card2 :: [] when card1 /=/ card2 -> true | _ -> false not (hasState Splitting hand) && isPair() let decisions = [Hit; Stand] let split = if canSplit() then [Split] else [] let doubleDown = if hasState Initial hand then [DoubleDown] else [] decisions @ split @ doubleDown to this: type Hand // ...stuff... member hand.GetDecisions = let (/=/) (c1 : Card) (c2 : Card) = c1.MatchValue = c2.MatchValue let canSplit() = let isPair() = match hand.Cards with | card1 :: card2 :: [] when card1 /=/ card2 -> true | _ -> false not (hand.HasState Splitting) && isPair() let decisions = [Hit; Stand] let split = if canSplit() then [Split] else [] let doubleDown = if hand.HasState Initial then [DoubleDown] else [] decisions @ split @ doubleDown Now, I don't doubt I'm an idiot, but other than (I'm guessing) making C# interop easier, what did that gain me? Specifically, I found a couple *dis*advantages, not counting the extra work of conversion (which I won't count, since I could have done it this way in the first place, I suppose, although that would have made using F# Interactive more of a pain). For one thing, I'm now no longer able to work with function "pipelining" easily. I had to go and change some |> chained |> calls to (some |> chained).Calls etc. Also, it seemed to make my type system dumber--whereas with my original version, my program needed no type annotations, after converting largely to member methods, I got a bunch of errors about lookups being indeterminate at that point, and I had to go and add type annotations (an example of this is in the (/=/) above). I hope I haven't come off too dubious, as I appreciate the advice I received, and writing idiomatic code is important to me. I'm just curious why the idiom is the way it is :) Thanks!

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  • Is it possible to set a default behaviour for custom (non-native) methods/functions in Java?

    - by Tom
    Is it possible to set a default behaviour for custom (non-native) methods/functions in Java? For example, I would like to change the default "Function" to do a System.out.println("message") whenever called. So, when a custom method/function is being created: public String testMethod() { //custom code } it should execute the newly added default behaviour (in this case the system output), before the custom code is run. Even if this would be a bad excercise, is it possible? Maybe by extending the function class or something?

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  • SQL SERVER – Fun Post – Connecting Same SQL Server using Different Methods

    - by pinaldave
    Yesterday I had faced error when I was connecting SQL Server using 127.0.0.1. I had immediately checked if SQL Server is working perfectly by connecting to it by specifiing my local box computer. While I was doing this suddenly I realize that it is indeed interesting to know how many different way we can connect to SQL Server which is installed in the local box. I created list of 5 different way but I am sure there are many more ways and I would like to document there here. Here is my setup. I am attempting to connect to the default instance of SQL Server from the same system where it is installed. Method 1: Connecting using local host IP 127.0.0.1 Method 2: Connecting using just a single dot (.) Method 3: Connecting using (local) Method 4: Connecting using localhost Method 5: Connecting using computer name – in my case it is BIG Here are my two questions for you? (Scroll below the image) 1) Which is your favorite method? 2) What are other methods you are familiar with to connect to local host? Reference: Pinal Dave (http://blog.SQLAuthority.com)     Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Writing cross-platforms Types, Interfaces and Classes/Methods in C++

    - by user827992
    I'm looking for the best solution to write cross-platform software, aka code that I write and that I have to interface with different libraries and platforms each time. What I consider the easiest part, correct me if I'm wrong, is the definition of new types, all I have to do is to write an hpp file with a list of typedefs, I can keep the same names for each new type across the different platforms so my codebase can be shared without any problem. typedefs also helps me to redefine a better scope for my types in my code. I will probably end up having something like this: include |-windows | |-types.hpp |-linux | |-types.hpp |-mac |-types.hpp For the interfaces I'm thinking about the same solution used for the types, a series of hpp files, probably I will write all the interfaces only once since they rely on the types and all "cross-platform portability" is ensured by the work done on the types. include | |-interfaces.hpp | |-windows | |-types.hpp |-linux | |-types.hpp |-mac | |-types.hpp For classes and methods I do not have a real answer, I would like to avoid 2 things: the explicit use of pointers the use of templates I want to avoid the use of the pointers because they can make the code less readable for someone and I want to avoid templates just because if I write them, I can't separate the interface from the definition. What is the best option to hide the use of the pointers? I would also like some words about macros and how to implement some OS-specifics calls and definitions.

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  • A good substitute for ASMX web service methods, but not a general handler

    - by Saeed Neamati
    The best thing I like about ASP.NET MVC, is that you can directly call a server method (called action), from the client. This is so convenient, and so straightforward, that I really like to implement such a model in ASP.NET WebForms too. However, in ASP.NET WebForms, to call a server method from the client, you should either use Page Methods, or Web Services, both of which use SOAP as their communication protocol (though JSON can also be used). There is also another substitution, which is using Generic Handlers. The problem with them however is that, a separate Generic Handler should be written for each server method. In other words, each Generic Handler works like a simple method. Is there anyway else to imitate MVC model in ASP.NET WebForms? Please note that I can't change to MVC platform right now, cause the project at our hand is a big project and we don't have required resources and time to change our platform. What we seek, is a simple MVC model implementation for our AJAX calls. A problem that we have with Web Services, is the known problem of SoapException, and we're not interested in creating custom SoapExctensions.

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  • Webserver not giving the correct response on CURL and other httprequest methods [migrated]

    - by Maxim
    I am trying to make a REST request to a external webserver by using this code <?php $user = 'USER'; $pass = 'PASS'; $data = "MYDATA" $ch = curl_init('URL'); curl_setopt($ch, CURLOPT_POST, true); curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); curl_setopt($ch, CURLOPT_POSTFIELDS, $data); curl_setopt($ch, CURLOPT_HTTPHEADER, array( 'Content-Type: application/json', 'Content-Length: ' . strlen($data)) ); curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); curl_setopt($ch, CURLOPT_VERBOSE, true); if(!($res = curl_exec($ch))) { echo('[cURL Failure] ' . curl_error($ch)); } curl_close($ch); echo($res); Now this is a CURL request, however i tried different methods to test my result and they all give me a 403 forbidden error response that i get from the webserver, however i do get a 200 response when i run it on any other webserver (localhost, webserver2, ...) Therefore i think there is something wrong with my webserver and it might be disallowing/caching the post parameters that i provide because sometimes it returns a 200 response but most of the times it returns the 403. This is the response i get : HTTP/1.1 403 Forbidden Accept-Ranges: bytes Content-Type: application/json; charset=UTF-8 Date: Sat, 26 Oct 2013 13:56:37 GMT Server: Restlet-Framework/2.1.3 Vary: Accept-Charset, Accept-Encoding, Accept-Language, Accept Content-Length: 77 Connection: keep-alive {"error":"ForbiddenOperationException","errorMessage":"Invalid credentials."} It says Invalid credentials however i provide the correct credentials and i can confirm them because it is working on other servers. Since this is a crucial part of my script that i use for clients to register i assume that there is something wrong with the post parameters. I am running cpanel and uninstalled the following already: - varnish - apachebooster i also recompiled php already and enabled curl and its dependencies but nothing seems to resolve my problem. If more information is required then don't hesitate to ask me in the comments i will respond very quickly as i really need this. any help is appreciated. Kind regards Maxim

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  • What to Return with Async CRUD methods

    - by RualStorge
    While there is a similar question focused on Java, I've been in debates with utilizing Task objects. What's the best way to handle returns on CRUD methods (and similar)? Common returns we've seen over the years are: Void (no return unless there is an exception) Boolean (True on Success, False on Failure, exception on unhandled failure) Int or GUID (Return the newly created objects Id, 0 or null on failure, exception on unhandled failure) The updated Object (exception on failure) Result Object (Object that houses the manipulated object's ID, Boolean or status field to with success or failure indicated, Exception information if there was one, etc) The concern comes into play as we've started moving over to utilizing C# 5's Async functionality, and this brought the question up of how we should handle CRUD returns large-scale. In our systems we have a little of everything in regards to what we return, we want to make these returns standardized... Now the question is what is the recommended standard? Is there even a recommended standard yet? (I realize we need to decide our standard, but typically we do so by looking at best practices, see if it makes sense for us and go from there, but here we're not finding much to work with)

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  • Transform coordinates from 3d to 2d without matrix or built in methods

    - by Thomas
    Not to long ago i started to create a small 3D engine in javascript to combine this with an html5 canvas. One of the issues I run into is how can you transform 3d to 2d coords. Since I cannot use matrices or built in transformation methods I need another way. I've tried implementing the next explanation + pseudo code: http://freespace.virgin.net/hugo.elias/routines/3d_to_2d.htm Unfortunately no luck there. I've replace all the input variables with data from my own camera and object classes. I have the following data: An object with a rotation, position vector and an array of 4 3d coords (its just a plane) a camera with a position and rotation vector the viewport - a square 600 x 600 surface. The example uses a zoom factor which I've set as 1 Most hits on google use either matrix calculations or don't implement camera rotation. Basic transformation should be like this: screen.x = x / z * zoom screen.y = y / z * zoom Can anyone point me in the right direction or explain to me howto achieve this? edit: Thanks for all your posts, I haven't been able to apply all this to my project yet but I hope to do this soon.

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  • What methods should save/load a game state

    - by vedi
    There are a lot of articles about how to save a state of a game and they are pretty good. But I have one conceptual misunderstanding where should I save the state? My game has number of screens and pair of them are MainMenuScreen and MainSceneScreen these are inherited from Screen class. MainMenuScreen is shown at start of the game the MainSceneScreen little later. What is the problem? I navigated to MainSceneScreen, forced Android to stop the application (I change a language settings on the device to achieve it, please let me know if I'm wrong). After that I select the application again and I can see MainMenuScreen is shown. But I want MainSceneScreen to be shown. I suppose I should override resume method. But what class I should override? I have class PsGame that extends Game class of libgdx. I put breakpoints to its resume method and it turned out that method was not called. I investigated the problem and I've found little strange code in onResume method of AndroidApplication class of libgdx: if (!firstResume) graphics.resume(); else firstResume = false; My debugger said firstResume was true and didn't go to *graphics.resume()*line. Sorry for a lot of words but could you answer following question: What did I do wrong? What methods should I override? Thank you in advance.

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  • Should we test all our methods?

    - by Zenzen
    So today I had a talk with my teammate about unit testing. The whole thing started when he asked me "hey, where are the tests for that class, I see only one?". The whole class was a manager (or a service if you prefer to call it like that) and almost all the methods were simply delegating stuff to a DAO so it was similar to: SomeClass getSomething(parameters) { return myDao.findSomethingBySomething(parameters); } A kind of boilerplate with no logic (or at least I do not consider such simple delegation as logic) but a useful boilerplate in most cases (layer separation etc.). And we had a rather lengthy discussion whether or not I should unit test it (I think that it is worth mentioning that I did fully unit test the DAO). His main arguments being that it was not TDD (obviously) and that someone might want to see the test to check what this method does (I do not know how it could be more obvious) or that in the future someone might want to change the implementation and add new (or more like "any") logic to it (in which case I guess someone should simply test that logic). This made me think, though. Should we strive for the highest test coverage %? Or is it simply an art for art's sake then? I simply do not see any reason behind testing things like: getters and setters (unless they actually have some logic in them) "boilerplate" code Obviously a test for such a method (with mocks) would take me less than a minute but I guess that is still time wasted and a millisecond longer for every CI. Are there any rational/not "flammable" reasons to why one should test every single (or as many as he can) line of code?

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  • Avoid overwriting all the methods in the child class

    - by Heckel
    The context I am making a game in C++ using SFML. I have a class that controls what is displayed on the screen (manager on the image below). It has a list of all the things to draw like images, text, etc. To be able to store them in one list I created a Drawable class from which all the other drawable class inherit. The image below represents how I would organize each class. Drawable has a virtual method Draw that will be called by the manager. Image and Text overwrite this method. My problem is that I would like Image::draw method to work for Circle, Polygon, etc. since sf::CircleShape and sf::ConvexShape inherit from sf::Shape. I thought of two ways to do that. My first idea would be for Image to have a pointer on sf::Shape, and the subclasses would make it point onto their sf::CircleShape or sf::ConvexShape classes (Like on the image below). In the Polygon constructor I would write something like ptr_shape = &polygon_shape; This doesn't look very elegant because I have two variables that are, in fact, just one. My second idea is to store the sf::CircleShape and sf::ConvexShape inside the ptr_shape like ptr_shape = new sf::ConvexShape(...); and to use a function that is only in ConvexShape I would cast it like so ((sf::ConvexShape*)ptr_shape)->convex_method(); But that doesn't look very elegant either. I am not even sure I am allowed to do that. My question I added details about the whole thing because I thought that maybe my whole architecture was wrong. I would like to know how I could design my program to be safe without overwriting all the Image methods. I apologize if this question has already been asked; I have no idea what to google.

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  • What to Return with Async CRUD methods C#

    - by RualStorge
    While there is a similar question focused on Java, I've been in debates with utilizing Task objects. What's the best way to handle returns on CRUD methods (and similar)? Common returns we've seen over the years are: Void (no return unless there is an exception) Boolean (True on Success, False on Failure, exception on unhandled failure) Int or GUID (Return the newly created objects Id, 0 or null on failure, exception on unhandled failure) The updated Object (exception on failure) Result Object (Object that houses the manipulated object's ID, Boolean or status field to with success or failure indicated, Exception information if there was one, etc) The concern comes into play as we've started moving over to utilizing C# 5's Async functionality, and this brought the question up of how we should handle CRUD returns large-scale. In our systems we have a little of everything in regards to what we return, we want to make these returns standardized... Now the question is what is the recommended standard? Is there even a recommended standard yet? (I realize we need to decide our standard, but typically we do so by looking at best practices, see if it makes sense for us and go from there, but here we're not finding much to work with)

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  • Static / Shared Helper Functions vs Built-In Methods

    - by Nathan
    This is a simple question but a design consideration that I often run across in my day to day development work. Lets say that you have a class that represents some kinds of collection. Public Class ModifiedCustomerOrders Public Property Orders as List(Of ModifiedOrders) End Class Within this class you do all kinds of important work, such as combining many different information sources and, eventually, build the Modified Customer Orders. Now, you have different processes that consume this class, each of which needs a slightly different slice of the ModifiedCustomerOrders items. To enable this, you want to add filtering functionality. How do you go about this? Do you: Add Filtering calls to the ModifiedCustomerOrders class so that you can say: MyOrdersClass.RemoveCanceledOrders() Create a Static / Shared "tooling" class that allows you to call: OrdersFilters.RemoveCanceledOrders(MyOrders) Create an extension method to accomplish the same feat as #2 but with less typing: MyOrders.RemoveCanceledOrders() Create a "Service" method that handles the getting of Orders as appropriate to the calling function, while using one of the previous approaches "under the hood". OrdersService.GetOrdersForProcessA() Others? I tend to prefer the tooling / extension method approaches as they make testing a little bit simpler. Although I dependency inject all my sourcing data into the ModifiedCustomerOrders, having it as part of the class makes it a little bit more complicated to test. Typically, I choose to use extension methods where I am doing parameterless transformations / filters. As they get more complex, I will move it into a static class instead. Thoughts on this approach? How would you approach it?

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  • Useful WatiN Extension Methods

    - by Steve Wilkes
    I've been doing a fair amount of UI testing using WatiN recently – here’s some extension methods I've found useful. This checks if a WatiN TextField is actually a hidden field. WatiN makes no distinction between text and hidden inputs, so this can come in handy if you render an input sometimes as hidden and sometimes as a visible text field. Note that this doesn't check if an input is visible (I've got another extension method for that in a moment), it checks if it’s hidden. public static bool IsHiddenField(this TextField textField) { if (textField == null || !textField.Exists) { return false; } var textFieldType = textField.GetAttributeValue("type"); return (textFieldType != null) && textFieldType.ToLowerInvariant() == "hidden"; } The next method quickly sets the value of a text field to a given string. By default WatiN types the text you give it into a text field one character at a time which can be necessary if you have behaviour you want to test which is triggered by individual key presses, but which most of time is just painfully slow; this method dumps the text in in one go. Note that if it's not a hidden field then it gives it focus first; this helps trigger validation once the value has been set and focus moves elsewhere. public static void SetText(this TextField textField, string value) { if ((textField == null) || !textField.Exists) { return; } if (!textField.IsHiddenField()) { textField.Focus(); } textField.Value = value; } Finally, here's a method which checks if an Element is currently visible. It does so by walking up the DOM and checking for a Style.Display of 'none' on any element between the one on which the method is invoked, and any of its ancestors. public static bool IsElementVisible(this Element element) { if ((element == null) || !element.Exists) { return false; } while ((element != null) && element.Exists) { if (element.Style.Display.ToLowerInvariant().Contains("none")) { return false; } element = element.Parent; } return true; } Hope they come in handy

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  • LINQ – Skip() and Take() methods

    - by nmarun
    I had this issue recently where I have an array of integers and I’m doing some Skip(n) and then a Take(m) on the collection. Here’s an abstraction of the code: 1: int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 }; 2: var taken = numbers.Skip(3).Take(3); 3: foreach (var i in taken) 4: { 5: Console.WriteLine(i); 6: } The output is as expected: 3, 9, 8 – skip the first three and then take the next three items. But, what happens if I do something like: 1: var taken = numbers.Skip(7).Take(5); In English – skip the first seven and the take the next 5 items from an array that contains only 10 elements. Think it’ll throw the IndexOutOfRangeException exception? Nope. These extension methods are a little smarter than that. Even though the user has requested more elements than what exists in the collection, the Take method only returns the first three thereby making the output of the program as: 7, 2, 0. The scenario is handled similarly when you do: 1: var taken = numbers.Take(5).Skip(7); This one takes the first 5 elements from the numbers array and then skips 7 of them. This is what is looks like in the debug mode: Just wanted to share this behavior.

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