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  • How to force VS to react on a changing of an attached property in design time?

    - by sedovav
    Imagine, we have a wpf class library with a window1.xaml and a resource dictionary res.xaml defined in it. I know how to use styles that defined in the res.xaml for the controls that defined into the window: <Window x:Class="...Window1"> <Window.Resources> <ResourceDictionary> <ResourceDictionary.MergedDictionaries> <ResourceDictionary Source="res.xaml"/> </ResourceDictionary.MergedDictionaries> </ResourceDictionary> <\Window.Resources> </Window> So we can use the dictionary's styles for all elements into the window (except the window element... I don't know how to set the style from the res.xaml for the window :( ). I saw the article where describes how to create and use attached property to add resource dictionaries to a FrameworkElement.Resources.MergedDictionaries list. It's good! We can do the same as we done in the example above but we can use the window style now. It looks like this: <Window x:Class="...Window1" xmlns: resources="..." resources:SharedResources.MergedDictionaries="res.xaml"> </Window> That's good but VS2008 cannot recognize resources from res.xaml in design time. So we have a sad situation: all styles from res.xaml are available in run-time but in the design-time VS cannot display the window (it can't find the mentioned styles). Does anybody know how to fix this situation?

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  • OpenSceneGraph C++ Access Violation reading location 0x00421000

    - by Kobojunkie
    Working with OpenSceneGraph, and I keep running into this violation issue that I would appreciate some help with. The problem is with the particular line below which happens to be the first in my main function. osg::ref_ptr<osg::Node> bench = osgDB::readNodeFile("Models/test.IVE"); I have my models folder right in my directory. The error is as below. Unhandled exception at 0x68630A6C (msvcr100.dll) in OSG3D.exe: 0xC0000005: Access violation reading location 0x00421000. And this is where the problem seems to be coming up. /** Read an osg::Node from file. * Return valid osg::Node on success, * return NULL on failure. * The osgDB::Registry is used to load the appropriate ReaderWriter plugin * for the filename extension, and this plugin then handles the request * to read the specified file.*/ inline osg::Node* readNodeFile(const std::string& filename) { return readNodeFile(filename,Registry::instance()->getOptions()); } I would appreciate details on how best to tackle this kind of exception message in the future. Are there tools that make this easy to debug or are there ways to capture the exact issues and fix them? I would appreciate any help with this. My ultimate goal is to learn how to better debug C++ related issues please. With this, it means reading through the compiler error list http://msdn.microsoft.com/en-us/library/850cstw1(v=vs.71).aspx is not enough

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  • speed up sql INSERTs

    - by sean717
    I have the following method to insert millions of rows of data into a table (I use SQL 2008) and it seems slow, is there any way to speed up INSERTs? Here is the code snippet - I use MS enterprise library public void InsertHistoricData(List<DataRow> dataRowList) { string sql = string.Format( @"INSERT INTO [MyTable] ([Date],[Open],[High],[Low],[Close],[Volumn]) VALUES( @DateVal, @OpenVal, @High, @Low, @CloseVal, @Volumn )"); DbCommand dbCommand = VictoriaDB.GetSqlStringCommand( sql ); DB.AddInParameter(dbCommand, "DateVal", DbType.Date); DB.AddInParameter(dbCommand, "OpenVal", DbType.Currency); DB.AddInParameter(dbCommand, "High", DbType.Currency ); DB.AddInParameter(dbCommand, "Low", DbType.Currency); DB.AddInParameter(dbCommand, "CloseVal", DbType.Currency); DB.AddInParameter(dbCommand, "Volumn", DbType.Int32); foreach (NasdaqHistoricDataRow dataRow in dataRowList) { DB.SetParameterValue( dbCommand, "DateVal", dataRow.Date ); DB.SetParameterValue( dbCommand, "OpenVal", dataRow.Open ); DB.SetParameterValue( dbCommand, "High", dataRow.High ); DB.SetParameterValue( dbCommand, "Low", dataRow.Low ); DB.SetParameterValue( dbCommand, "CloseVal", dataRow.Close ); DB.SetParameterValue( dbCommand, "Volumn", dataRow.Volumn ); DB.ExecuteNonQuery( dbCommand ); } }

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  • jsf and eclipse setup. Lib in Explorer is different than lib in tomcat. How come?

    - by user384706
    Hi, I am starter in JSF2.0, and I have a question related to Eclipse (I am using Helios). 1)I create a Dynamic Project 2)I add JSF project facet. 3)I choose JSF user library (I have created it using MyFaces) All ok so far. I notice though that in the Project Explorer in WebContent/WEB-INF/lib the lib directory is empty instead of having MyFaces jars. The application works fine though. I looked into this and the jars are actually being placed in the corresponding lib directory of the app deployed under wtpwebapps of the Tomcat instance of eclipse in the .pluggins directory. Ok, it works but IMHO it is incorrect to have the Project Explorer inconsistent with the directories actually deployed. I.e. lib is shown empty in Project Explorer but with jars under wtpwebapps. Am I wrong to dislike this inconsistency? Is this how it should work or am I doing something wrong in the way I am setting my project? Thanks!

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  • jQuery Scrollable Dynamic

    - by Coron3r
    Hi, I am doing a site where I need to change dynamically the amount of items in one slide depending on the resolution. I'm using the Jquery Tools scrollable For better understanding, here is the basic markup <div class="scrollable"> <!-- root element for the items --> <div class="items"> <!-- 1-5 --> <div> <img src="http://farm1.static.flickr.com/143/321464099_a7cfcb95cf_t.jpg" /> <img src="http://farm4.static.flickr.com/3089/2796719087_c3ee89a730_t.jpg" /> <img src="http://farm1.static.flickr.com/79/244441862_08ec9b6b49_t.jpg" /> <img src="http://farm1.static.flickr.com/28/66523124_b468cf4978_t.jpg" /> <img src="http://farm1.static.flickr.com/164/399223606_b875ddf797_t.jpg" /> </div> <!-- 5-10 --> <div> <img src="http://farm1.static.flickr.com/163/399223609_db47d35b7c_t.jpg" /> <img src="http://farm1.static.flickr.com/135/321464104_c010dbf34c_t.jpg" /> <img src="http://farm1.static.flickr.com/40/117346184_9760f3aabc_t.jpg" /> <img src="http://farm1.static.flickr.com/153/399232237_6928a527c1_t.jpg" /> <img src="http://farm1.static.flickr.com/50/117346182_1fded507fa_t.jpg" /> </div> <!-- 10-15 --> <div> <img src="http://farm4.static.flickr.com/3629/3323896446_3b87a8bf75_t.jpg" /> <img src="http://farm4.static.flickr.com/3023/3323897466_e61624f6de_t.jpg" /> <img src="http://farm4.static.flickr.com/3650/3323058611_d35c894fab_t.jpg" /> <img src="http://farm4.static.flickr.com/3635/3323893254_3183671257_t.jpg" /> <img src="http://farm4.static.flickr.com/3624/3323893148_8318838fbd_t.jpg" /> </div> </div> </div> Ok and now I would like to set, that if I have a resolution bellow 1440, I would show only e.g. 3 images <div class="scrollable"> <!-- root element for the items --> <div class="items"> <!-- 1-3 --> <div> <img src="http://farm1.static.flickr.com/143/321464099_a7cfcb95cf_t.jpg" /> <img src="http://farm4.static.flickr.com/3089/2796719087_c3ee89a730_t.jpg" /> <img src="http://farm1.static.flickr.com/79/244441862_08ec9b6b49_t.jpg" /> </div> <!-- 3-6 --> <div> <img src="http://farm1.static.flickr.com/163/399223609_db47d35b7c_t.jpg" /> <img src="http://farm1.static.flickr.com/135/321464104_c010dbf34c_t.jpg" /> <img src="http://farm1.static.flickr.com/40/117346184_9760f3aabc_t.jpg" /> </div> ..etc </div> </div> I know that I should use the screen.width(); function but how to slice and parse it depending on the resolution? Thanks for your comments!

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  • Why doesn't this CompiledQuery give a performance improvement?

    - by Grammarian
    I am trying to speed up an often used query. Using a CompiledQuery seemed to be the answer. But when I tried the compiled version, there was no difference in performance between the compiled and non-compiled versions. Can someone please tell me why using Queries.FindTradeByTradeTagCompiled is not faster than using Queries.FindTradeByTradeTag? static class Queries { // Pre-compiled query, as per http://msdn.microsoft.com/en-us/library/bb896297 private static readonly Func<MyEntities, int, IQueryable<Trade>> mCompiledFindTradeQuery = CompiledQuery.Compile<MyEntities, int, IQueryable<Trade>>( (entities, tag) => from trade in entities.TradeSet where trade.trade_tag == tag select trade); public static Trade FindTradeByTradeTagCompiled(MyEntities entities, int tag) { IQueryable<Trade> tradeQuery = mCompiledFindTradeQuery(entities, tag); return tradeQuery.FirstOrDefault(); } public static Trade FindTradeByTradeTag(MyEntities entities, int tag) { IQueryable<Trade> tradeQuery = from trade in entities.TradeSet where trade.trade_tag == tag select trade; return tradeQuery.FirstOrDefault(); } }

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  • Run script after Jquery finish

    - by Felipe Fernández
    First let's explain the hack that I was trying to implement. When using Total Validator Tool through my web page and I get following error: [WCAG v1 6.3 (A), US-508-l] Consider providing a alternative after each tag As my page relies heavily on javascript I can't provide a real alternative, so I decided to add an empty noscript tag after every script appearence. Let's say I need to provide a clean report about accesibility about my web page even the hack is senseless. (I know the hack is unethical and silly, let's use it as example material, but the point of my post are the final questions) I tried the following approach: $(document).ready(function(){ $("script").each(function() { $(this).after("<noscript></noscript>"); }); }); The problem raises because I have a jQueryUI DatePicker component on my page. jQuery adds a script section after the DOM is ready so my hack fails as miss this section. So the questions are: How handles jQuery library to be executed after document is ready? How can I run my code after jQuery finish its labours?

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  • jquerycropping,codiegniter,php

    - by user345804
    I want to crop the image using jquery,codigniter in jquery i get four coordinate of image x1=249 x2=326 y1=194 y2=271 w=77 h=77 in codiegniter done the query function do_crop() { $x=249; $y=194; $w=77; $h=77; $path= 'system/application/'; $config = array( 'image_library' => 'gd2', 'source_image' => $path.'/jag1/flowers.jpg' , 'new_image' => $path.'/jag2/flowers.jpg', 'maintain_ration' => false, 'width' => $w, 'height' => $h, 'x_axis' => $x, 'y_axis' => $y ); $this->load->library('image_lib'); $this->image_lib->initialize($config); if ( ! $this->image_lib->crop()) { echo $this->image_lib->display_errors(); } $this->image_lib->clear(); } i get cropped image. But problem is don't get exact cropped image x,y coordinate problem

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  • Packaging Java apps for the Windows/Linux desktop.

    - by alexmcchessers
    I am writing an application in Java for the desktop using the Eclipse SWT library for GUI rendering. I think SWT helps Java get over the biggest hurdle for acceptance on the desktop: namely providing a Java application with a consistent, responsive interface that looks like that belonging to any other app on your desktop. However, I feel that packaging an application is still an issue. OS X natively provides an easy mechanism for wrapping Java apps in native application bundles, but producing an app for Windows/Linux that doesn't require the user to run an ugly batch file or click on a .jar is still a hassle. Possibly that's not such an issue on Linux, where the user is likely to be a little more tech-savvy, but on Windows I'd like to have a regular .exe for him/her to run. Has anyone had any experience with any of the .exe generation tools for Java that are out there? I've tried JSmooth but had various issues with it. Is there a better solution before I crack out Visual Studio and roll my own? Edit: I should perhaps mention that I am unable to spend a lot of money on a commercial solution.

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  • How do C and C++ interpreters bind identifiers to functions

    - by sub
    I'm talking about C and/or C++ here as this are the only languages I know used for interpreters where the following could be a problem: If we have an interpreted language X how can a library written for it add functions to the language which can then be called from within programs written in the language? PHP example: substr( $str, 5, 10 ); How is the function substr added to the "function pool" of PHP so it can be called from within scripts? It is easy for PHP storing all registered function names in an array and searching through it as a function is called in a script. However, as there obviously is no eval in C(++), how can the function then be called? I assume PHP doesn't have 100MB of code like: if( identifier == "substr" ) { return PHP_SUBSTR(...); } else if( ... ) { ... } Ha ha, that would be pretty funny. I hope you have understood my question so far. How do C/C++ interpreters solve this problem? How can I solve this for my own experimental toy interpreter?

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  • How to animate a path like it's being drawn, dot by dot? (Raphael.js)

    - by Anton
    How to animate a vector path like it's being drawn by hand? In other words, slowly show the path pixel by pixel. I'm using Raphaël.js, but if your answer is not library specific—like maybe there's some general programming pattern for doing that kind of thing (I'm fairly new to vector animation)—it's welcome! Update I know it's easy to do with straight paths, as easy as an example on that page:: path("M114 253").animate({path: "M114 253 L 234 253"}); But try to change code on that page, say, this way:: path("M114 26").animate({path: "M114 26 C 24 23 234 253 234 253"}); And you'll see what I mean. Path is certainly animated from it initial state (point "M114 26") to the end state (curve "C 24 23 234 253 234 253" starting on point "M114 26"), but not in a way specified in question, not like it's being drawn. (Sorry for not making clear from the start that I don't mean animating straight lines.) I don't see how animateAlong can do that either. It can animate an object along a path, and how can I make this path to gradually show itself while object is being animated along it?

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  • At what point is it worth using a database?

    - by radix07
    I have a question relating to databases and at what point is worth diving into one. I am primarily an embedded engineer, but I am writing an application using QT to interface with our controller. We are at an odd point where we have enough data that it would be feasible to implement a database (around 700+ items and growing) to manage everything, but I am not sure it is worth the time right now to deal with. I have no problems implementing the GUI with files generated from excel and parsed in, but it gets tedious and hard to track even with VBA scripts. I have been playing around with converting our data into something more manageable for the application side with Microsoft Access and that seems to be working well. If that works out I am only a step (or several) away from using an SQL database and using the QT library to access and modify it. I don't have much experience managing data at this level and am curious what may be the best way to approach this. So what are some of the real benefits of using a database if any in this case? I realize much of this can be very application specific, but some general ideas and suggestions on how to straddle the embedded/application programming line would be helpful. Thanks

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  • Java: JGraphT: Iterate through nodes

    - by Rosarch
    I'm trying to iterate through all nodes, so I can print them out for graphviz. What is the best way to do that using the JGraphT library? public static void main(String[] args) { UndirectedGraph<String, DefaultEdge> g = new SimpleWeightedGraph<String, DefaultEdge>(DefaultEdge.class); String odp = "ODP"; String cck = "CCK"; String mfe = "MFE"; g.addVertex(odp); g.addVertex(cck); g.addVertex(mfe); g.addEdge(odp, cck); g.addEdge(odp, mfe); } Also, how do I add edge weights? Edit: This seems to work pretty well. But is there a better way? Set<DefaultEdge> edges = g.edgeSet(); for (DefaultEdge e : edges) { gv.addln(String.format("\"%s\" -> \"%s\"", g.getEdgeSource(e), g.getEdgeTarget(e))); }

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  • How do interpreters written in C and C++ bind identifiers to C(++) functions

    - by sub
    I'm talking about C and/or C++ here as this are the only languages I know used for interpreters where the following could be a problem: If we have an interpreted language X how can a library written for it add functions to the language which can then be called from within programs written in the language? PHP example: substr( $str, 5, 10 ); How is the function substr added to the "function pool" of PHP so it can be called from within scripts? It is easy for PHP storing all registered function names in an array and searching through it as a function is called in a script. However, as there obviously is no eval in C(++), how can the function then be called? I assume PHP doesn't have 100MB of code like: if( identifier == "substr" ) { return PHP_SUBSTR(...); } else if( ... ) { ... } Ha ha, that would be pretty funny. I hope you have understood my question so far. How do interpreters written in C/C++ solve this problem? How can I solve this for my own experimental toy interpreter written in C++?

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  • Semaphore - What is the use of initial count?

    - by Sandbox
    http://msdn.microsoft.com/en-us/library/system.threading.semaphoreslim.aspx To create a semaphore, I need to provide an initial count and maximum count. MSDN states that an initial count is - The initial number of requests for the semaphore that can be granted concurrently. While it states that maximum count is The maximum number of requests for the semaphore that can be granted concurrently. I can understand that the maximum count is the maximum number of threads that can access a resource concurrently. But, what is the use of initial count? If I create a semaphore with an initial count of 0 and a maximum count of 2, none of my threadpool threads are able to access the resource. If I set the initial count as 1 and maximum count as 2 then only thread pool thread can access the resource. It is only when I set both initial count and maximum count as 2, 2 threads are able to access the resource concurrently. So, I am really confused about the significance of initial count? SemaphoreSlim semaphoreSlim = new SemaphoreSlim(0, 2); //all threadpool threads wait SemaphoreSlim semaphoreSlim = new SemaphoreSlim(1, 2);//only one thread has access to the resource at a time SemaphoreSlim semaphoreSlim = new SemaphoreSlim(2, 2);//two threadpool threads can access the resource concurrently

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  • visual studio attaching to a process in debug mode

    - by user1612986
    i have a strange problem. the dll that i built (lets call it my.dll) in c++ visual studio 2010 uses a third party library (say tp.lib) which in turn calls a third party dll (say tp.dll). for debugging prupose i have in configurationProperties-debugging-command: Excel.exe and configurationProperties-debugging-commandArguments: "$(TargetPath)" in my computer i also set PATH variable to the directory where tp.dll resides now when i hit the F5 in visual studio excel opens up with my.dll and crashes giving me a "cannot open in dos mode" error. the reason this happens is tp.dll is not deployed when debug version of my.dll is deployed. when i open an instance of excel seperately and manually drop the debug version of my.dll then everything works fine and i can see all my functions that i wrote in my.dll the only issue is now i do not know how to debug becuase i do not know how to attach visual studio to the instance of excel i opened up seperately. my question is: 1 how can i attach visual studio to an already opened instance of Excel or 2 how can i hit F5 and still make Excel pick up the required tp.dll from the directory specified in the PATH variable before it starts to deploy my.dll. any of these two will allow my to step through the code for the purpose of debugging. thanks in advance.

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  • How to handle 30k files in a project which requires them?

    - by Jeremiah
    Visual Studio 2010 RC - Silverlight Application We have a library of images that we need to have access to. They are given to us from a vendor (through an installer) and they are not in a database, they are files in a folder (a very large monster of a folder). We do not control when the images change, so the vendor needs to be able to override them individually. We get updates frequently enough from this vendor to state that these images change "randomly" and without our (programmer) knowledge. The problem: I don't want 30K images in SVN. Heck, I don't even want to imagine them in my Solution. However, our application requires them in order to run properly. So, our build/staging servers need access to these images (we have two build servers). The Question: How would you handle it when your application will not work as specified without access to each of 30k images and you don't control when those images change? I'm do not want to have a crazy large SVN repository. Because I don't know when any of these images change, I really don't want them in my solution (definitely do not want a large solution, either). I also don't want a bunch of manual steps to do every time these images change. Our mantra, up to this point, has always been, any developer could download from SVN, compile and run our app. These images are going to kill that mantra. I'm tempted to make a WCF service that will return images if they exist and a dummy image if they don't. This way all dev boxes will return a dummy image and our build/staging/production boxes will return real images (ones that actually have the vendor's image installer installed on). This has to be a solved problem. What have other people done to handle these types of problems? I'm open to suggestions.

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  • Evaluating creation of GUI via file vs coding

    - by nevets1219
    I'm working on a utility that will be used to test the project I'm currently working on. What the utility will do is allow user to provide various inputs and it will sends out requests and provide the response as output. However, at this point the exact format (which input is required and what is optional) has yet to be fleshed out. In addition, coding in Swing is somewhat repetitive since the overall work is simple though this should be the safest route to go as I have more or less full control and every component can be tweaked as I want. I'm considering using a configuration file that's in XML to describe the GUI (at least one part of it) and then coding the event handling part (in addition to validation, etc). The GUI itself shouldn't be too complicated. For each type of request to make there's a tab for the request and within each tab are various inputs. There seems to be quite a few questions about this already but I'm not asking for a 3rd party library to do this. I'm looking to do this myself, since I don't think it'll be too overly complicated (hopefully). My main consideration for using this is re-usability (later on, for other projects) and for simplifying the GUI work. My question is: are there other pros/cons that I'm overlooking? Is it worth the (unknown) time to do this? I've built GUI in VB.NET and with Flex3 before.

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  • Are Thread.stop and friends ever safe in Java?

    - by Stephen C
    The stop(), suspend(), and resume() in java.lang.Thread are deprecated because they are unsafe. The Sun recommended work around is to use Thread.interrupt(), but that approach doesn't work in all cases. For example, if you are call a library method that doesn't explicitly or implicitly check the interrupted flag, you have no choice but to wait for the call to finish. So, I'm wondering if it is possible to characterize situations where it is (provably) safe to call stop() on a Thread. For example, would it be safe to stop() a thread that did nothing but call find(...) or match(...) on a java.util.regex.Matcher? (If there are any Sun engineers reading this ... a definitive answer would be really appreciated.) EDIT: Answers that simply restate the mantra that you should not call stop() because it is deprecated, unsafe, whatever are missing the point of this question. I know that that it is genuinely unsafe in the majority of cases, and that if there is a viable alternative you should always use that instead. This question is about the subset cases where it is safe. Specifically, what is that subset?

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  • How can I write to a single xml file from two programs at the same time?

    - by Tom Bushell
    We recently started working with XML files, after many years of experience with the old INI files. My coworker found some CodeProject sample code that uses System.Xml.XmlDocument.Save. We are getting exceptions when two programs try to write to the same file at the same time. System.IO.IOException: The process cannot access the file 'C:\Test.xml' because it is being used by another process. This seems obvious in hindsight, but we had not anticipated it because accessing INI files via the Win32 API does not have this limitation. I assume there's some arbitration done by the Win32 calls that work at a higher level than the the XmlDocument.Save method. I'm hoping there are higher level XML routines somewhere in the .Net library that work similarily to the Win32 functions, but don't know where to start looking. Or maybe we can set up our file access permissions to allow multiple programs to write to the same file? Time is short (like almost all SW projects), and if we can't find a solution quickly, we'll have to hold our noses and go back to INI files.

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  • Help me sort programing languages a bit

    - by b-gen-jack-o-neill
    Hi, so I asked here few days ago about C# and its principles. Now, if I may, I have some additional general questions about some languages, becouse for novice like me, it seems a bit confusing. To be exact I want to ask more about language functions capabilities than syntax and so. To be honest, its just these special functions that bothers me and make me so confused. For exmaple, C has its printf(), Pascal has writeln() and so. I know in basic the output in assembler of these funtions would be similiar, every language has more or less its special functions. For console output, for file manipulation, etc. But all these functions are de-facto part of its OS API, so why is for example in C distinguished between C standard library functions and (on Windows) WinAPI functions when even printf() has to use some Windows feature, call some of its function to actually show desired text on console window, becouse the actuall "showing" is done by OS. Where is the line between language functions and system API? Now languages I dont quite understand - Python, Ruby and similiar. To be more specific, I know they are similiar to java and C# in term they are compiled into bytecode. But, I do not unerstand what are its capabilities in term of building GUI applications. I saw tutorial for using Ruby to program GUI applications on Linux and Windows. But isn´t that just some kind of upgrade? I mean fram other tutorials It seemed like these languages was first intended for small scripts than building big applications. I hope you understand why I am confused. If you do, please help me sort it out a bit, I have no one to ask.

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  • I cant put a string in a switch nor an array in a class

    - by TimothyTech
    Okay, im making a pretty big file in my opinion, so i wanted to separate it into several files for cleaner code. so i have my main .cpp file and two header files holding my classes. well the header files dont hold strings, it aboslutely wont budge. i call the library in both my .cpp file and even tried it in my header file. another issue i ran into is using strings to make switches function, reason being if i use integers in a switch if the user inputs a alphabetical character the program goes into an endless loop. string choice; switch (choice) { case "1" : //... break; case "2" : //... break; } and my last issue is when i create an object in a case it gives an error. says cross initialization of object. string choice; switch (choice) { case "1" : Class object; break; case "2" : //... break; }

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  • MySQL Datefields: duplicate or calculate?

    - by Konerak
    We are using a table with a structure imposed upon us more than 10 years ago. We are allowed to add columns, but urged not to change existing columns. Certain columns are meant to represent dates, but are put in different format. Amongst others: * CHAR(6): YYMMDD * CHAR(6): DDMMYY * CHAR(8): YYYYMMDD * CHAR(8): DDMMYYYY * DATE * DATETIME Since we now would like to do some more complex queries, using advanced date functions, my manager proposed to d*uplicate those problem columns* to a proper FORMATTED_OLDCOLUMNNAME column using a DATE or DATETIME format. Is this the way to go? Couldn't we just use the STR_TO_DATE function each time we accessed the columns? To avoid every query having to copy-paste the function, I could still work with a view or a stored procedure, but duplicating data to avoid recalculation sounds wrong. Solutions I see (I guess I prefer 2.2.1) 1. Physically duplicate columns 1.1 In the same table 1.1.1 Added by each script that does a modification (INSERT/UPDATE/REPLACE/...) 1.1.2 Maintained by a trigger on each modification 1.2 In a separate table 1.2.1 Added by each script that does a modification (INSERT/UPDATE/REPLACE/...) 1.2.2 Maintained by a trigger on each modification 2. On-demand transformation 2.1 Each query has to perform the transformation 2.1.1 Using copy-paste in the source code 2.1.2 Using a library 2.1.3 Using a STORED PROCEDURE 2.2 A view performs the transformation 2.2.1 A separate table replacing the entire table 2.2.2 A separate table just adding the date-fields for the primary keys Am I right to say it's better to recalculate than to store? And would a view be a good solution?

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  • Image Gurus: Optimize my Python PNG transparency function

    - by ozone
    I need to replace all the white(ish) pixels in a PNG image with alpha transparency. I'm using Python in AppEngine and so do not have access to libraries like PIL, imagemagick etc. AppEngine does have an image library, but is pitched mainly at image resizing. I found the excellent little pyPNG module and managed to knock up a little function that does what I need: make_transparent.py pseudo-code for the main loop would be something like: for each pixel: if pixel looks "quite white": set pixel values to transparent otherwise: keep existing pixel values and (assuming 8bit values) "quite white" would be: where each r,g,b value is greater than "240" AND each r,g,b value is within "20" of each other This is the first time I've worked with raw pixel data in this way, and although works, it also performs extremely poorly. It seems like there must be a more efficient way of processing the data without iterating over each pixel in this manner? (Matrices?) I was hoping someone with more experience in dealing with these things might be able to point out some of my more obvious mistakes/improvements in my algorithm. Thanks!

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  • LINQ to SQL: NOTing a prebuilt expression

    - by ck
    I'm building a library of functions for one of my core L2S classes, all of which return a bool to allow checking for certain situations. Example: Expression<Func<Account, bool>> IsSomethingX = a => a.AccountSupplementary != null && a.AccountSupplementary.SomethingXFlag != null && a.AccountSupplementary.SomethingXFlag.Value; Now to query where this is not true, I CAN'T do this: var myAccounts= context.Accounts .Where(!IsSomethingX); // does not compile However, using the syntax from the PredicateBuilder class, I've come up with this: public static IQueryable<T> WhereNot<T>(this IQueryable<T> items, Expression<Func<T, bool>> expr1) { var invokedExpr = Expression.Invoke(expr1, expr1.Parameters.Cast<Expression>()); return items.Where(Expression.Lambda<Func<T, bool>> (Expression.Not(invokedExpr), expr1.Parameters)); } var myAccounts= context.Accounts .WhereNot(IsSomethingX); // does compile which actually produces the correct SQL. Does this look like a good solution, and is there anything I need to be aware of that might cause me problems in future?

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