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• Is this a situation where Qt Model/View architecture is not useful?

  - by csmithmaui

  Hi, I am writing a GUI based application where I read a string of values from serial port every few seconds and I need to display most of the values in some type graphical indicator(I was thinking of QprogressBar maybe) that displays the range and the value. Some of the other data that I am parsing from the string are the date and fault codes. Also, the data is hierarchical. I wanted to use the model/view architecture of Qt because I have been interested in MVC stuff for a while but have never quite wrapped my brain around how to implement it very well. As of now, I have subclassed QAbstractItemModel and in the model I read the serial port and wrap the items parsed from the string in a Tree data structure. I can view all of the data in a QtreeView with no issues. I have also began to subclass QAbstractItemView to build my custom view with all of the Graphical Indicators and such. This is where I am getting stuck. It seems to me that in order for me to design a view that knows how to display my custom model the view needs to know exactly how all of the data in the model is organized. Doesn't that defeat the purpose of Model/View? The QTreeView I tested the model with is basically just displaying the model as it is setup in the Tree structure but I don't want to do that because the data is not all of the same type. Is the type of data or the way you would like to present it to the user a determining factor in whether or not you should use this architecture? I always assumed it was just always better to design in an MVC style. It seems to me like it might have been better to just subclass QWidget and then read in from the serial port and update all of subwidgets(graphical indicators, labels, etc...) from the subclass. Essentially, do everything in one class. Does anybody understand this issue that can explain to me either what I am missing or why I shouldn't be doing it this way. As of now I am a little confused. Thanks so much for any help!

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• How to determine which inheriting class is using an abstract class' methods.

  - by Kin

  In my console application have an abstract Factory class "Listener" which contains code for listening and accepting connections, and spawning client classes. This class is inherited by two more classes (WorldListener, and MasterListener) that contain more protocol specific overrides and functions. I also have a helper class (ConsoleWrapper) which encapsulates and extends System.Console, containing methods for writing to console info on what is happening to instances of the WorldListener and MasterListener. I need a way to determine in the abstract ListenerClass which Inheriting class is calling its methods. Any help with this problem would be greatly appreciated! I am stumped :X Simplified example of what I am trying to do. abstract class Listener { public void DoSomething() { if(inheriting class == WorldListener) ConsoleWrapper.WorldWrite("Did something!"); if(inheriting class == MasterListener) ConsoleWrapper.MasterWrite("Did something!"); } } public static ConsoleWrapper { public void WorldWrite(string input) { System.Console.WriteLine("[World] {0}", input); } } public class WorldListener : Listener { public void DoSomethingSpecific() { ConsoleWrapper.WorldWrite("I did something specific!"); } } public void Main() { new WorldListener(); new MasterListener(); } Expected output [World] Did something! [World] I did something specific! [Master] Did something! [World] I did something specific!

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• ASP.Net MVC Where do you convert from Entities to ViewModels?

  - by Pino

  Title pretty much explains it all, its the last thing I'm trying to work into our project. We are structured with a Service Library which contains a function like so. /// <summary> /// Returns a single category based on the specified ID. /// </summary> public Category GetCategory(int CategoryID) { var RetVal = _session.Single<Category>(x => x.ID == CategoryID); return RetVal; } Now Category is a Entity (We are using Entity Framework) we need to convert that to a CategoryViewModel. Now, how would people structure this? Would you make sure the service function returned a CategoryViewModel? Have the controller pull the data from the service then call another function to covnert to a view model?

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• What is the best way to post data from web browser to server?

  - by Kronass

  Hi, I want to know what is the best way to send data from web browser to server using post method. I've seen a practice where they wrap all the elements data in XML, convert it into Base64 string and then post it to the server (via Ajax or hidden field). this way will not work if the Javascript is disabled, any how if I ignored this. is it a good practice to wrap elements into XML (or create my custom wrapper in general) and post them to server saying it will enhance the maintainability of the code or just stick with the classical way and no need to add unnecessary text in the post.

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• Setting up a multi-site CMS, collecting thoughts about the DB schema

  - by Ben Fransen

  Hello all, I'm collecting some thoughts about creating a multisite CMS. In my opinion there are two major approaches. All data is stored into 1 database, giving me the advantage of single point of updates; Seperated databases, so each client has its own database. Giving me the advantage to measure bandwith. Option 1 gives me the disadvantage of measuring bandwith while option is giving me the disadvantage of a single point of update structure. Are there any generic approaches for creating a sort of update system? So my clients can download a small package (maybe a zip with a conf file to tell the updatescript where to put all the files and how to extend the database??) Do you guys have some thougths about the best solution for a situation like this? I have my own webserver, full access to all resources and I'm developing in PHP with MySQL as DBMS. I hope to hear from you and I surely appreciate any effort you make to help me further! Greets from Holland, Ben Fransen

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• How to refactor use of the general Exception?

  - by Colin

  Our code catches the general exception everywhere. Usually it writes the error to a log table in the database and shows a MessageBox to the user to say that the operation requested failed. If there is database interaction, the transaction is rolled back. I have introduced a business logic layer and a data access layer to unravel some of the logic. In the data access layer, I have chosen not to catch anything and I also throw ArgumentNullExceptions and ArgumentOutOfRangeExceptions so that the message passed up the stack does not come straight from the database. In the business logic layer I put a try catch. In the catch I rollback the transaction, do the logging and rethrow. In the presentation layer there is another try catch that displays a MessageBox. I am now thinking about catching a DataException and an ArgumentException instead of an Exception where I know the code only accesses a database. Where the code accesses a web service, then I thought I would create my own "WebServiceException", which would be created in the data access layer whenever an HttpException, WebException or SoapException is thrown. So now, generally I will be catching 2 or 3 exceptions where currently I catch just the general Exception, and I think that seems OK to me. Does anyone wrap exceptions up again to carry the message up to the presentation layer? I think I should probably add a try catch to Main() that catches Exception, attempts to log it, displays an "Application has encountered an error" message and exits the application. So, my question is, does anyone see any holes in my plan? Are there any obvious exceptions that I should be catching or do these ones pretty much cover it (other than file access - I think there is only 1 place where we read-write to a config file).

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• advice on working on remote asp.net applications

  - by Jonesy

  Hi folks, I'm a (relatively new) developer using asp.net with VB.NET. Currently all my applications are developed on my PC and then are built and moved onto the web server. I'm going to be working remotely for 3 months in which time I'll be connecting to the company network via VPN. What is the best way to access my projects? I need to have the projects stored on the company network so that others can access them too. So simply copying the projects to my laptop, working on them, then copying them back won't suffice. I tried to just open the projects off of the network share but am getting application trust problems. I'm just wondering what other developers do in this situation? Jonesy

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• Scripting Languages vs. Compiled Languages for web development

  - by Austin Hyde

  Though I come from a purely PHP background on the web development side of programming, I have also spent much time with C# and C++ on the desktop. I don't really want to spark any flame wars, but: When should you use scripting languages over compiled languages for website development? (and vice versa) Just to clarify, for the sake of this question, I define a "scripting language" to mean an interpreted language like PHP, Python, or Ruby, and a "compiled language" to mean a strongly typed, compiled language like C#, C++, Java, or VB.

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• New design patterns/design strategies

  - by steven

  I've studied and implemented design patterns for a few years now, and I'm wondering. What are some of the newer design patterns (since the GOF)? Also, what should one, similar to myself, study [in the way of software design] next? Note: I've been using TDD, and UML for some time now. I'm curious about the newer paradigm shifts, and or newer design patterns.

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• How to automatically fix MISSING reference in a dll when a referenced library is broken in VB6?

  - by systempuntoout

  What do you do when you break compatibility on a common library used by many other libraries? What i usually do is: For every dll that reference the broken one Checkout dll Checkout vbp project Open vpb project with VB6 Ide Click on References button Uncheck MISSING reference and OK Click on References button Check references and OK Click on Make dll Close project This can be a pita activity, when you have many Dll to recompile and it can be error prone because you could miss some Dll (anyway we have continuous integration that alert this cases). What's your best practice to handle this scenario?

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• Using C Structs which contains ObjC Objects?

  - by GuidoMB

  I'm using C structs in objc and I've created a function that assembles the structure like the one from the Cocoa API. The things is that this structure is not like NSRect o NSPoint this structure packs objc objects soo I'm seeing a potential memory leak here. Do I need to provide a function to 'release' the structure? I'am not creating a ISKNewsCategory class because there will be no behavior but Do you think this is a good approach or I should define the class even doe there will be no behavior? typedef struct ISK_NewsCategory { NSString *name; NSString *code } ISKNewsCategory; NS_INLINE ISKNewsCategory ISKMakeNewsCategory(NSString *name, NSString *code) { ISKNewsCategory category; category.name = [name retain]; category.code = [code retain]; return category; }

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• effective retrieve for a voting system in PHP

  - by Adnan

  Hello, I have a system where registered users can vote up/vote down comment for a picture. Something very similar to SO's voting system. I store the votes in a table with values as such; vote_id | vote_comment_id | vote_user_id | vote_date Now I have few a question concerned the speed and efficiency for the following; PROB: Once a user opens the picture page with comments I need, if that user has already voted UP/DOWN a comment to show it like; "you voted up" or "you voted down" next to the comment (in SO it the vote image is highlighted) MY POSSIBLE SOL: Right now when I open a picture page for each comment I loop thru, I loop thru my table of votes as well and check if a user has voted and show the status (I compare the vote_user_id with the user's session). How efficient is this? Anyone have a better approach to tackle this kind of problem?

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• Repair bad character due to encoding problem

  - by remi bourgarel

  Hi all, Recently we had an encoding problem in our system : If we had the string "æ" in our db ,it became "æ" on our web pages. Now this problem is solved, but the problem is that now we have a lot of "æ" in our database : users didn't see and validate pre-filled form with these characters. I found that If you read in utf 8 C3A6 you'll get "æ", if you read it in ascii you'll get "æ". It's strange because if I execute "select convert(varbinary(40),N'æ'),convert(varbinary(40),'æ')" I don't have the same result... Do you have any idea on how I can fix my database (ie change all "æ" to "æ") ? thx

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• Bad crypto error in .NET 4.0

  - by Andrey

  Today I moved my web application to .net 4.0 and Forms Auth just stopped working. After several hours of digging into my SqlMembershipProvider (simplified version of built-in SqlMembershipProvider), I found that HMACSHA256 hash is not consistent. This is the encryption method: internal string EncodePassword(string pass, int passwordFormat, string salt) { if (passwordFormat == 0) // MembershipPasswordFormat.Clear return pass; byte[] bIn = Encoding.Unicode.GetBytes(pass); byte[] bSalt = Convert.FromBase64String(salt); byte[] bAll = new byte[bSalt.Length + bIn.Length]; byte[] bRet = null; Buffer.BlockCopy(bSalt, 0, bAll, 0, bSalt.Length); Buffer.BlockCopy(bIn, 0, bAll, bSalt.Length, bIn.Length); if (passwordFormat == 1) { // MembershipPasswordFormat.Hashed HashAlgorithm s = HashAlgorithm.Create( Membership.HashAlgorithmType ); bRet = s.ComputeHash(bAll); } else { bRet = EncryptPassword( bAll ); } return Convert.ToBase64String(bRet); } Passing the same password and salt twice returns different results!!! It was working perfectly in .NET 3.5 Anyone aware of any breaking changes, or is it a known bug? UPDATE: When I specify SHA512 as hashing algorithm, everything works fine, so I do believe it's a bug in .NET 4.0 crypto Thanks! Andrey

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• Crashes when using AVAudioPlayer on iPhone

  - by mindthief

  Hi all, I am trying to use AVAudioPlayer to play some sounds in quick succession. When I invoke the sound-playing function less frequently so that the sounds play fully before the function is invoked again, the application runs fine. But if I invoke the function quickly in rapid succession (so that sounds are played while the previous sounds are still being played), the app eventually crashes after ~20 calls to the function, with the message "EXC_BAD_ACCESS". Here is code from the function: NSString *nsWavPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:wavFileName]; AVAudioPlayer* theAudio = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:nsWavPath] error:NULL]; theAudio.delegate = self; [theAudio play]; As mentioned in another thread, I implemented the following delegate function: - (void) audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag { if(!flag) NSLog(@"audio did NOT finish successfully\n"); [player release]; } But the app still crashes after around ~20 rapid calls to the function. Any idea what I'm doing wrong?

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• Bash or Bourne Scripts?

  - by sixtyfootersdude

  Is it better practice to write Bash scripts or Bourne scripts? My team writes Bourne scripts but I am not entirely sure why. If this is a holy war question (ie: vim vs. emacs) please just reply: holy war.

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• Dropping support for IE6, Is swfObject still relevant?

  - by Armitage

  We have recently dropped support for IE6 at my job. The other developers have have opted for a generic object embed method: <object type="application/x-shockwave-flash" data="example.swf" width="800" height="600" > <param name="movie" value="example.swf"> <param name="allowScriptAccess" value="always"> </object> This seems to work in all modern browsers but it really rubs me the wrong way. I'm sure this is wrong in several ways and is clearly a big step back in sophistication. So my question is in 2 parts, what is wrong with the above method? Is swfObject still best practice and what issues does it solve (besides IE6 click-activate)? Citations less then a year old would also be helpful.

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• Non-Mainstream Languages, Bad for your resume?

  - by Joe

  Hi folks, I got my BS in Computer Science about seven years ago. I spent two years in neuroscience research and the next three providing what amounts to tech support. But I love computer programming - and I have since written, as a freelancer, non-trivial commercial code in Haskell, Smalltalk, and Objective-C. I used these languages because I find them rewarding, they make me a better programmer and thus, I thought, more attractive to companies. However the polar opposite has occured and I am now unhireable. The freelance market has bottomed out and I am looking for regular employment. But I am being repeatedly turned down, even for entry-level positions, because I don't specifically fit the requirements - eg. Java programmer with 2+ years with JUnit, JavaMail, Servlets etc. And none of the hiring managers, let alone the recruiters, have heard of either Haskell or Smalltalk and more disturbing is their thinly veiled contempt for my background. My question is , how should I market myself to these positions? Is anyone here in a similar position? What should I be doing different professionally? More broadly is this contempt for non-mainstream experience occurring everywhere or just my town? And if there are any hiring managers reading this, I'd love to hear your side. Please be brutally honest. thanks, joe

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• To HTML 5 or not to HTML 5 ?

  - by ZX12R

  I am a designer whose main marketing strategy is multi browser compatibility. I assure my clients that the site will work even in IE6 (!). Of late i have been pondering over the question of moving to HTML 5. The reason behind my apprehension is that IE6 is still a major player in terms of market share and i don't want to lose it. Is there any way of moving to HTML 5 and still promise multi browser compatibility? Thank you.

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• Methods for Lazy Initialization with properties

  - by Stuart Pegg

  I'm currently altering a widely used class to move as much of the expensive initialization from the class constructor into Lazy Initialized properties. Below is an example (in c#): Before: public class ClassA { public readonly ClassB B; public void ClassA() { B = new ClassB(); } } After: public class ClassA { private ClassB _b; public ClassB B { get { if (_b == null) { _b = new ClassB(); } return _b; } } } There are a fair few more of these properties in the class I'm altering, and some are not used in certain contexts (hence the Laziness), but if they are used they're likely to be called repeatedly. Unfortunately, the properties are often also used inside the class. This means there is a potential for the private variable (_b) to be used directly by a method without it being initialized. Is there a way to make only the public property (B) available inside the class, or even an alternative method with the same initialized-when-needed? This is reposted from Programmers (not subjective enough apparently): http://programmers.stackexchange.com/questions/34270/best-methods-for-lazy-initialization-with-properties

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• Is it naughty to have a large utility file?

  - by banister

  In my C project I have quite a large utils.c file. It is really full of many utilities of different sorts. I feel a bit naughty just stuffing different miscellaneous functions in there. For example it has some utilities related to low level stuff such as a lowercase() function, and it also has some quite sophisticated utilities such as converting to/from different colour formats. My question is, is it very naughty to have such a large utils.c with many different types of utilities in it? Should I break it up into many different kinds of utility files? Such as graphics_utils.c and so on What do you think?

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• Which layer should create DataContext?

  - by Kevin

  I have a problem to decide which layer in my system should create DataContext. I have read a book, saying that if do not pass the same DataContext object for all the database updates, it will sometimes get an exception thrown from the DataContext. That's why i initially create new instance of DataContext in business layer, and pass it into data access layer. So that the same datacontext is used for all the updates. But this lead to one design problem, if i wanna change my DAL to Non-LinqToSQL in future, i need to re-write the code in business layer as well. Please give me some advice on this. Thanks. Example code 'Business Layer Public Sub SaveData(name As String) Using ts AS New TransactionScope() Using db As New MyDataContext() DAL.Insert(db,name) DAL.Insert(db,name) End Using ts.Complete() End Using End Sub 'Data Access Layer Public Sub Insert(db as MyDataContext,name As string) db.TableAInsert(name) End Sub

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• comparator with null values.

  - by pvgoddijn

  Hi, We have some code wich sorts a list of addresses based on the distance between their coordinates. this is done through collections.sort with a custom comparator. However from time to time an adress without coordinates is in the list causing a NullPointerException. My initial idea to fix this was to have the comparator return 0 as dististance for addresses where at least one of the coordinates is null. I fear this might lead to corruption of the order the 'valid' elements in the list. so is returning a '0' values for null data in a comparator ok, or is there a cleaner way to resolve this.

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• Iterate Multi-Dimensional Array with Nested Foreach Statement

  - by Tyler Murry

  I think this might be a pretty simple question, but I haven't been able to figure it out yet. If I've got a 2-dimensional array like so: int[,] = new int[2,3] { {1, 2, 3}, {4, 5, 6} }; What's the best way to iterate through each dimension of the array with a nested foreach statement?

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• Best way to organize MATLAB classes?

  - by jjkparker

  MATLAB has two ways of organizing classes: @-directories: @ClassName\ ClassName.m Method1.m Method2.m Single files: ClassName.m: classdef ClassName methods % all methods included here end end The first style existed before the new classdef syntax, but seems to be a more structured way of doing things. The second style (everything in a single file) is new. Which method do you use, and why?

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