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• Advantage of using Thread.Start vs QueueUserWorkItem

  - by Cheeso

  In multithreaded .NET programming, what are the decision criteria for using ThreadPool.QueueUserWorkItem versus starting my own thread via new Thread() and Thread.Start()? In a server app (let's say, an ASP.NET app or a WCF service) I think the ThreadPool is always there and available. What about in a client app, like a WinForms or WPF app? Is there a cost to spin up the thread pool? If I just want 3 or 4 threads to work for a short period on some computation, is it better to QUWI or to Thread.Start().

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• Difference between mutableArrayValueForKey and calling insertObject:inEmployeesAtIndex: directly

  - by jasonbogd

  I have a question regarding using KVO-compliant methods to insert/remove objects from an array. I'm working through Aaron Hillegass' Cocoa Programming for Mac OS X and I saw the following line of code (in the insertObject:inEmployeesAtIndex: method: [[undoManager prepareWithInvocationTarget:self] removeObjectFromEmployeesAtIndex:index]; Correct me if I'm wrong, but I always thought it was better to call mutableArrayValueForKey: and then removeObjectAtIndex:...so I tried changing the above line to this: [[undoManager prepareWithInvocationTarget:[self mutableArrayValueForKey:@"employees"]] removeObjectAtIndex:index]; And it didn't work. Can someone explain the difference and why the first line works but the second line doesn't?

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• Can a grails controller extend from a base class? How to make it so grails doesn't blow up?

  - by egervari

  I wrote a base class to help build my controllers more quickly and to remove duplication. It provides some helper methods, default actions and some meta programming to make these things easier to build. One of those methods in the base class is like this: def dynamicList(Class clazz) { def model = new LinkedHashMap() model[getMapString(clazz) + "s"] = list(clazz) model[getMapString(clazz) + "sTotal"] = count(clazz) model } The action that calls it, also in the base class, is this: def list = { dynamicList(clazz) } Unfortunately, when I go to list action in the controller subclass that inherits the base class when my application is deployed, I get this exception: groovy.lang.MissingMethodException: No signature of method: groovy.lang.MissingMethodException.dynamicList() is applicable for argument types: (java.lang.Class) values: [class project .user.User] at project.user.UserController$_closure1.doCall(UserController.groovy:18) at project.user.UserController$_closure1.doCall(UserController.groovy) at java.lang.Thread.run(Thread.java:619) How can I hit grails over the head and just tell it do what I want it to do? My controller unit tests run just fine, so grails' run-time is totally at fault :/ Ken

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• Overview of PHP shorthand

  - by James Simpson

  I've been programming in PHP for years now, but I've never learned how to use any shorthand. I come across it from time to time in code and have a hard time reading it, so I'd like to learn the different shorthand that exists for the language sot hat I can read it and start saving time/lines by using it, but I can't seem to find a comprehensive overview of all of the shorthand. A Google search pretty much exclusively shows the shorthand for if/else statements, but I know there must be more than just that. By shorthand, I am talking about stuff like: ($var) ? true : false;

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• design time usercontrols - I can't see anything!

  - by taglius

  newbie question, please forgive... I'm developing a Wpf UserControl that will eventually be bound to a business object. The usercontrol is little more than a series of laid out TextBlocks, and perhaps (later) an image or two. As I'm laying out the usercontrol, I can put dummy text into all the TextBlocks so I can see what the usercontrol will look like, but as soon as I change the text property to contain the Binding information: <TextBlock Margin="0,12.8,42,0" Name="lblLastName" FontSize="8" Height="19" VerticalAlignment="Top" Text="{Binding Mode=OneWay, Path=LastName}"/> Then I can no longer see the textbox, or any "placeholder" text. This makes it very difficult to adjust the location and sizes of all the controls on the UserControl. In WinFormas programming, you could set binding information independently of the Text property, so you could at least see the Placeholder text during design time development. It's going to be pretty hard to visually arrange a bunch of invisible TextBlocks! What's the standard solution for this?

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• Best calculator software to help programmers

  - by RHaguiuda

  As a embedded systems programmer I always need to make lots of base conversions (dec to hex, hex to bin and so on...), and I must admit: Windows 7 calculator is a good calc, but too limited in my point of view. I work a lot with communications protocols and it`s common to need some base conversion in this field of knowledge. I`m looking for a calculator software (not a hardware one), to help with base conversions, but it must also support scientific calc. Can anyone help on this? Since this subject is intended to help programmers, I did not ask this in SuperUser.com. Thanks.

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• How to assign default values and define unique keys in Entity Framework 4 Designer

  - by csharpnoob

  Hello, I've had a look at the Entity Framework 4. While generating code for the SQL Server 2008 I came to the point where I want to define some default values for some fields. how to define in the designer for a Created DateTime Field the DateTime.Now default value? - Error 54: Default value (DateTime.Now) is not valid for DateTime. The value must be in the form 'yyyy-MM-dd HH:mm:ss.fffZ' how to make for code generation a string Field unique. Like E-Mail or Username can exists only once in the table. I've search alot in the internet and also checked my books Pro Entity Framework 4.0 and Programming Entity Framework. But none of them seems to come up with the default value issue, or using sql commands as default values for database generation. Another thing is, how to prevent on database generation always from droping tables? Instead i want to append non existing fields and keep the data. Thanks for any suggestions.

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• Simple cross platform GUI app

  - by Joe Cannatti

  I would like to know if there is any way that I could build a very simple GUI app (it doesn't even have to look good) that will run on a fresh install of Windows Vista and OS X with no other installations needed by the user. I would perfer not to use Java (just out of personal programming preference). I will use it though, if it is the only way. Specically, I am wondering if I can write a swing app with Scala or Groovy and run in on windows without them having to install anything. Sorry if this is a silly question, I am a Obj-C developer by trade.

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• cant login using System.Diagnostics.Process.Start

  - by omair iqbal

  i am tying to login using System.Diagnostics.Process.Start private void button1_Click(object sender, EventArgs e) { System.Diagnostics.Process.Start("iexplore","[email protected]","password","http://www.gmail.com"); } but visual studio gives me these 2 errors: Error 1 The best overloaded method match for 'System.Diagnostics.Process.Start(string, string, System.Security.SecureString, string)' has some invalid arguments C:\Documents and Settings\Omair\My Documents\Visual Studio 2008\Projects\WindowsFormsApplication3\WindowsFormsApplication3\Form1.cs 21 13 WindowsFormsApplication3 and Error 2 Argument '3': cannot convert from 'string' to 'System.Security.SecureString' C:\Documents and Settings\Omair\My Documents\Visual Studio 2008\Projects\WindowsFormsApplication3\WindowsFormsApplication3\Form1.cs 21 80 WindowsFormsApplication3 note: i am brand new to c# and reletively new to the world of programming sorry for my english

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• File Access problems with SLES 10 SP2 OES2 SP1

  - by Blackhawk131

  We have identified a couple of repeatable, demonstrable scenarios with unexplained rejected folder access on our servers for Mac users. Hopefully, this can be presented to Novell for a solution. What we did to demonstrate scenario 1; 1. setup a PC and Mac side-by-side 2. login to our server and open up to a central location on both Mac and PC 3. on the PC in that central location create a folder 4. on the Mac in that central location drag the created folder to the Mac desktop, this should work fine, no problem 5. on the PC rename that folder 6. on the Mac drag a file to that renamed folder, this should error with the following message; a. You cannot copy some of these items to the destination because their names are too long for the destination. Do you want to skip copying these items and continue copying the other items? b. Select skip, response is the filename is copied to the location with zero or small byte size. Try opening it and you get file is corrupted error message. What we did to demonstrate scenario 2; 1. setup a PC and Mac side-by-side 2. login to our server and open up to a central location on both Mac and PC 3. on the PC in that central location create a folder then create a subfolder 4. copy some content into the subfolder 5. on the Mac in that central location drag the created top level folder to the Mac desktop, this should work fine, no problem 6. on the PC rename that subfolder 7. on the Mac drag that top level folder to the Mac desktop, this should error on the Mac with the following; a. The operation cannot be completed because you do not have sufficient privileges for b. The operation cannot be completed because you do not have sufficient privileges for 8. on the Mac, if you open that subfolder you can see the file copied in step 4 above but, you can not open that file, you get the following message if you try; a. There was an error opening this document. You do not have permission to open this file. 9. on the PC drag some content into the top level folder 10. on the Mac you can open that file directly from the server or copy it locally, no problem, however-the subfolder is still corrupted or locked, whichever 11. on the PC rename the top level folder 12. on the Mac that same file just opened in step 10 above is now not accessible, get the following message; a. The document could not be opened. I have observed some variances in the above. For instance, a change on the PC side may take a moment before you can observer or act on the Mac side - kind of like the server is slow to respond. Also, the error message may vary. However, the key is once a folder, or subfolder, gets renamed by a PC, Mac problems commence. The solution is to create a new folder from a PC and copy the contents of the corrupted folder to the new folder and not rename the folder name. This has to be done on a PC because the corrupted folder is not accessible by a Mac user. Another problem that dovetails with the above is that we know certain characters are not allowed for PC folder or filenames. If a Mac user creates a folder with a slash in the file name, from the PC the user does not see that slash in the name. As soon as the PC user copies a file to that folder, the Mac user is locked from that folder. Will get the following error message; - Sorry, the operation could not be completed because an unexpected error occurred. - (Error code - 50) In addition to the above mentioned character issue with folders, the problem is more evil with filenames. If, for example, you create a file with a slash in the filename on a Mac and copy it to the server you will get the following error message; - You cannot copy some of these items to the destination because their names are too long for the destination. Do you want to skip copying these items and continue copying the other items? Select either Stop or Skip buttons. It does not matter which button is selected. The file name gets copied to the destination location at a reduced size. Depending on the file type, the icon associated with the file may or may not be present. Furthermore, if you open that file on the server you will get the following message; - Couldnt open the file. It may be corrupt or a file format that doesnt recognize. From the users perspective, if they are not observant of the icon or file size, they may disregard the error message and think their file has copied as intended. Only later do they discover the file is corrupt if they open that file. I want to make a note on this problem. It is the PC causing the issue. You can change folder and file names all day on a MAC and you don't have a problem as long as a character is not the issue. Once you change the file name or folder name from a PC the entire folder structure from that level down is corrupted. But it has to be resolved from a PC by creating a new folder and copying the contents to the new folder like stated above. Is something not configured correctly? SUSE Linux Enterprise Server 10 (x86_64) VERSION = 10 PATCHLEVEL = 2 LSB_VERSION="core-2.0-noarch:core-3.0-noarch:core-2.0-x86_64:core-3.0-x86_64" Novell Open Enterprise Server 2.0.1 (x86_64) VERSION = 2.0.1 PATCHLEVEL = 1 BUILD Note: We use Novell clients on all windows systems to connect to the servers for file access and network storage. We use AFP to allow OSx systems to connect to servers.

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• What are the Hot and Cold observables?

  - by Sergey Aldoukhov

  I watched the video and I know the general principles - hot happens even when nobody is subscribed, cold happens "on demand". Also, Publish() converts cold to hot and Defer() converts hot to cold. But still, I feel I am missing the details. Here are some questions I'd like to have answered: Can you give a comprehensive definition for these terms? Does it ever make sense to call Publish on hot observable or Defer on cold? Is there differences between hot and cold definitions for IObservable and IEnumerable? What are the general principles you should take into account when programming for cold or hot? Any other tips on hot/cold observables?

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• Developer Curriculum Vitae - "Experience"

  - by Neil Barnwell

  I've been involved in some interviews at work recently, and having seen a few CVs, I've been thinking of my own. I wonder how I might rate my proficiency at the various technologies I've worked with on some sort of simple scale: Beginner, Intermediate, Expert. I've been doing C# for a few years now, but I'd hesitate to call myself "expert" particularly (partly because surely I haven't been doing it long enough, and partly because I can't bring myself to be so bold as to say I'm expert at anything). I think I probably was expert at VB back when I got into programming, but any VB skills I had will have deteriorated by now. Of course I wouldn't even bother listing things on my CV that I'd consider myself to be "beginner" at, I'd just add them to the "other tech" category, but I'd be interested to hear tips on helping me decide.

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• iphone memory leaks and malloc?

  - by Brodie4598

  Okay so im finally to the point where I am testing my iPad App on an actual iPad... One thing that my app does is display a large (2mb) image in a scroll view. This is causing the iPad to get memory warnings. I run the app in the instruments to check for the leak. When I load the image, a leak is detected and i see the following in the allocations: ALl Allocations: 83.9 MB Malloc 48.55 MB: 48.55 MB Malloc 34.63 MB: 34.63 MB What im trying to understand is how to plug the leak obviously, but also why a 2MB image is causing a malloc of 20x that size I am very new to programming in obj-c so im sure this is an obvious thing, but I just cant figure it out. Here is the code:

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• how to profile multi threaded c++ app on linux?

  - by anon

  I used to do all my linux profiling with gprof. However, with my multi threaded app, it's output appears to be inconsistent. Now, I dug this up http://sam.zoy.org/writings/programming/gprof.html howver, it's from a long time ago -- and in my gprof output, it appears my gprof is listing functions used by non-main threads. So, my questions are: 1) in 2010, can I easily use gprof to profile multi threaded linux c++ apps? (ubuntu 9.10) 2) what other tools should I look into for profiling? thanks!

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• Way to check files in and out with multiple developers.

  - by Roeland

  I am a web developer working with 2-3 people including me. Our current setup is very simplistic. We try to let each other know when we are working on a specific file. We use FTP to edit our files. Recently we have run into the problem of 2 people accidentally editing one file, or working on a local file then uploading when another person just did the same. From what I have read I need some sort of control system. I have heard of subversion and mercurial. It seems that these systems may not be what I need though, since its just giving me different versions of the files. I don't know if it solves the issue of two people working on a file and overwriting each others work. What are your suggestions for solving my problem?

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• How to determine OS Platform with WMI?

  - by cary.wagner

  I am trying to figure out if there is a location in WMI that will return the OS Architecture (i.e. 32-bit or 64-bit) that will work across "all" versions of Windows. I thought I had figured it out looking at my Win2k8 system when I found the following: Win32_OperatingSystem / OSArchitecture I was wrong. It doesn't appear that this field exists on Win2k3 systems. Argh! So, is anyone aware of another field in WMI that "is" the same across server versions? If not, what about a registry key that is the same? I am using a tool that only allows me to configure simple field queries, so I cannot use a complex script to perform. Any help would be greatly appreciated! Cheers... Cary

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• In Cocoa, why won't a textfield be shown until after the IBAction is completely executed?

  - by Nano8Blazex

  I have an IBAction with some simple code inside: -(IBAction)change:(id)sender { [textfield setHidden:NO]; [self dolengthyaction]; } 'textfield' is an NSTextField in a nib file, and -'dolengthyaction' is a function that takes about a minute to finish executing. My question is: Why isn't the textfield shown until AFTER "dolengthyaction" is done executing? I want it to be revealed before the dolengthyaction starts taking place. Is this an inherent problem or is there something wrong with my code? (or in another part of my code?) I'm still not very good at programming so I apologize if I worded something badly and formatted something wrong.

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• How do I determine which C/C++ compiler to use?

  - by Adam Siddhi

  Greetings, I am trying to figure out which C/C++ compiler to use. I found this list of C/C++ compilers at Wikipedia: http://en.wikipedia.org/wiki/List_of_compilers#C.2FC.2B.2B_compilers I am fairly certain that I want to go with an open source compiler. I feel that if it is open source then it will be a more complete compiler since many programmer perspectives are used to make it better. Please tell me if you disagree. I should mention that I plan on learning C/C++ mainly to program 2D/3D game applications that will be compatible with Windows, Linux, MAC and iPhone operating systems. I am currently using Windows Vista x64 OS. Thanks, Adam

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• Getting an unexpected "?" at the end of a Registry GetValue in C#

  - by Wilhelm Peraud

  Hi, I use the Registry class to manage values in the Registry on Windows Seven in C#. Registry.GetValue(...); But, I'm facing a curious behavior : Every time, the returned value is the correct one, but sometimes, it is followed by an unexpected "?" When I check the Registry, (regedit), the "?" doesn't exist. I really don't understand from where this question mark come from. Could someone help me please ? Info : - C# - 3.5 framework - windows 7 64 bits (and i want my application to work on both 32 and 64 bits systems) Thank you in advance, Wilhelm

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• Cannot find sleep function

  - by Tyzak

  hello, i'm new at C Programming (i learned c++) i want to create a process with windows.h at first i just want to start my main programm that creates a process ( -- starts an other programm) that's my code, but it doesn't really work, i removed every unnessasery line of code but "void sleep(700)" (or "sleep (700)" for testing if the windows methods work, but i get an error, that "sleep" cant be found. #include <iostream> #include <windows.h> #include <string> using namespace std; void main() { //bool ret; //startupinfo stupinfo; //prozess_information pro2info; //Getstartupinfo (&stupinfo); //createprozess(null, "C:\\bsss10\\betriebssystemePRA1.exe", null, null, false, create_new_console, null, // null, &stupinfo, &pro2info); sleep (700); cout<< "hello"; } thanks in advance

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• How do I figure out which SOC or SDK board to use?

  - by Ram Bhat

  Hey guys Basically I'm working on a model of an automated vacuum cleaner. I currently have made software simulation of the same. How do I figure out which SOC or SDK board to use for the hardware implementation? My code is mostly written in C. Will this be compatible with the sdk provided by board manufacturers? How do i know what clock speed,memory etc the hardware will need? I'm a software guy and have only basic knowledge about practical hardware implementations. Have some experience in programming the 8086 to carry out basic tasks.

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• Correct Response For Questions Regarding Lack Of College Degree

  - by rofly

  I've managed to land two programming jobs so far with a partial college degree. One was an internship/co-op type position that turned full-time, while the other is contract work I've received mainly via circumstance. I have an interview forthcoming (my roommate works at the company) and they have already asked him why I have not completed my degree. The real reason is purely financial, but I was going to ask the SO community if there was any way I could spin this disadvantage to make it look more favorable. So, Stack Overflow: How can I look less like a slacker given the circumstances?

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• programmatically controlling power sockets in the UK

  - by cartoonfox

  It's very simple. I want to plug a lamp into the UK mains supply. I want to be able to power it on and off from software - say from serial port commands, or by running a command-line or something I can get to from ruby or Java. I see lots written about how to do this with X10 with American power systems - but has anybody actually tried doing this in the UK? If you got this working: 1) Exactly what hardware did you use? 2) How do you control it from software? Thanks!

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• How to disable horizontal scrolling within virtualbox on Ubuntu guest, Windows 7 host?

  - by Steven Rosato

  This post is a duplicate from superuser.com, but since I had no answers, I started to doubt it was a user question and maybe more of a programming question (because of the configuration files), so here it is: I am using Windows 7 as Host, Ubuntu Karmic as guest OS with guest tools installed and I get an annoying glitch when switching from host to the guest machine: vertical scrolling switches to horizontal! (using the mouse wheel). Since I don't really care about horizontal scrolling, how can I disable this? I have checked the web and the only thing I found was to play in the xorg.conf file and adding in the section "InputDevice" Option "ZAxisMapping" "4 5" which would enable vertical scrolling only. The thing is, I don't have that section in my config file so I guessed that I would need to add Section "InputDevice" Identifier "VBoxMouse" Driver "vboxmouse" Option "ZAxisMapping" "4 5" EndSection But that does not seem to work after restarting xserver. Any workaround for this?

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• Keyboard focus being stolen by Flash

  - by NewUser

  Performing a search, I noticed several questions dedicated to how to steal/trap the keyboard focus of the visitor. Considering this site is dedicated to programming that's not suprising. I was wondering if anyone can advise me on how to prevent this type of behavior. Losing keyboard focus to flash basically removes my browser's functionality until I use the mouse to click elsewhere (I use Mozilla Firefox). Anyone know of some kind of plugin or greasemonkey script that will prevent my keyboard focus from being stolen? Normal browser "shortcuts" are rendered useless by having to use the mouse to return keyboard focus to the browser. Edit: Reply to the post below, I do have flashblock / noscript and some other things. My issue is flash that I want to see/interact with stealing my focus. Basically looking for something I can toggle that will prevent flash from getting keyboard focus or a way to force my firefox keyboard commands to the browser

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