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• How do you obtain a formatted date and time for the current locale in C?

  - by jwaddell

  What C function should I call to obtain a formatted date and time for the locale where the program is being executed? I'm asking this question because I have run into a problem using the ClamAV daemon API. The VERSION command returns the date and time of the latest virus definitions, but the code uses a call to ctime to format it. As far as I can tell ctime does not format the datetime according to the current locale and uses the English abbreviations for days of the week and the month in the returned string. This causes problems as my Java program which uses the ClamAV API does respect the current locale and thus expects the day of the week and month name to have the local abbreviations. The datetime format would need to be in the same format as that produced by ctime: Www Mmm dd hh:mm:ss yyyy Where Www is the weekday, Mmm the month in letters, dd the day of the month, hh:mm:ss the time, and yyyy the year. I could rewrite the Java program to always assume English dates but I'd be happier to submit a patch to ClamAV as it seems like a bug on their side to me.

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• Organizing code, logical layout of segmented files

  - by David H

  I have known enough about programming to get me in trouble for about 10 years now. I have no formal education, though I've read many books on the subject for various languages. The language I am primarily focused on now would be php, atleast for the scale of things I am doing now. I have used some OOP classes for a while, but never took the dive into understanding principals behind the scenes. I am still not at the level I would like to be expression-wise...however my recent reading into a book titled The OOP Thought Process has me wanting to advance my programming skills. With motivation from the new concepts, I have started with a new project that I've coded some re-usable classes that deal with user auth, user profiles, database interfacing, and some other stuff I use regularly on most projects. Now having split my typical garbled spaghetti bowl mess of code into somewhat organized files, I've come into some problems when it comes to making sure files are all included when they need to be, and how to logically divide the scripts up into classes, aswell as how segmented I should be making each class. I guess I have rambled on enough about much of nothing, but what I am really asking for is advise from people, or suggested reading that focuses not on specific functions and formats of code, but the logical layout of projects that are larger than just a hobby project. I want to learn how to do things proper, and while I am still learning in some areas, this is something that I have no clue about other than just being creative, and trial/error. Mostly error. Thanks for any replies. This place is great.

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• Why use SQL database?

  - by martinthenext

  I'm not quite sure stackoverflow is a place for such a general question, but let's give it a try. Being exposed to the need of storing application data somewhere, I've always used MySQL or sqlite, just because it's always done like that. As it seems like the whole world is using these databases, most of all software products, frameworks, etc. It is rather hard for a beginning developer like me to ask a question - why? Ok, say we have some object-oriented logic in our application, and objects are related to each other somehow. We need to map this logic to the storage logic, so we need relations between database objects too. This leads us to using relational database and I'm ok with that - to put it simple, our database rows sometimes will need to have references to other tables' rows. But why do use SQL language for interaction with such a database? SQL query is a text message. I can understand this is cool for actually understanding what it does, but isn't it silly to use text table and column names for a part of application that no one ever seen after deploynment? If you had to write a data storage from scratch, you would have never used this kind of solution. Personally, I would have used some 'compiled db query' bytecode, that would be assembled once inside a client application and passed to the database. And it surely would name tables and colons by id numbers, not ascii-strings. In the case of changes in table structure those byte queries could be recompiled according to new db schema, stored in XML or something like that. What are the problems of my idea? Is there any reason for me not to write it myself and to use SQL database instead?

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• iOS 5 Audio Alarms Don't Sound Without kAudioSessionProperty_OverrideCategoryMixWithOthers On

  - by coneybeare

  I have an audio app that is having some problems with the way iOS 5 has changed audio behaviors. When my app's audio is playing (AVAudioSessionCategoryPlayback), and a Clock.app alarm or timer is fired from the OS, the UIAlertView notification pops up, but without the audio alert. My application sound ducks fine to get out of the way of the audio alert, but the alarm app's audio alert does not sound. Naturally, tons of support requests poured in over the iOS 5 change. I have solved this temporarily by setting kAudioSessionProperty_OverrideCategoryMixWithOthers which lets the alarm audio come through, but there are a few very undesirable side-effects when doing this: Other app's audio can play with/over mine. The remote control events are not routed to my app, but to iPod.app. None of the above drawbacks are acceptable for my app's requirements. I have been hacking away at this for some time now but haven't been able to crack it. How can I setup my audio such that: My app's audio still uses the AVAudioSessionCategoryPlayback category for background audio. The Clock.app alarms still have their audio alerts make sound The app still responds to remote control notifications

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• Covariance and Contravariance type inference in C# 4.0

  - by devoured elysium

  When we define our interfaces in C# 4.0, we are allowed to mark each of the generic parameters as in or out. If we try to set a generic parameter as out and that'd lead to a problem, the compiler raises an error, not allowing us to do that. Question: If the compiler has ways of inferring what are valid uses for both covariance (out) and contravariance(in), why do we have to mark interfaces as such? Wouldn't it be enough to just let us define the interfaces as we always did, and when we tried to use them in our client code, raise an error if we tried to use them in an un-safe way? Example: interface MyInterface<out T> { T abracadabra(); } //works OK interface MyInterface2<in T> { T abracadabra(); } //compiler raises an error. //This makes me think that the compiler is cappable //of understanding what situations might generate //run-time problems and then prohibits them. Also, isn't it what Java does in the same situation? From what I recall, you just do something like IMyInterface<? extends whatever> myInterface; //covariance IMyInterface<? super whatever> myInterface2; //contravariance Or am I mixing things? Thanks

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• Does this use of Monitor.Wait/Pulse have a race condition?

  - by jw

  I have a simple producer/consumer scenario, where there is only ever a single item being produced/consumed. Also, the producer waits for the worker thread to finish before continuing. I realize that kind of obviates the whole point of multithreading, but please just assume it really needs to be this way (: This code doesn't compile, but I hope you get the idea: // m_data is initially null // This could be called by any number of producer threads simultaneously void SetData(object foo) { lock(x) // Line A { assert(m_data == null); m_data = foo; Monitor.Pulse(x) // Line B while(m_data != null) Monitor.Wait(x) // Line C } } // This is only ever called by a single worker thread void UseData() { lock(x) // Line D { while(m_data == null) Monitor.Wait(x) // Line E // here, do something with m_data m_data = null; Monitor.Pulse(x) // Line F } } Here is the situation that I am not sure about: Suppose many threads call SetData() with different inputs. Only one of them will get inside the lock, and the rest will be blocked on Line A. Suppose the one that got inside the lock sets m_data and makes its way to Line C. Question: Could the Wait() on Line C allow another thread at Line A to obtain the lock and overwrite m_data before the worker thread even gets to it? Supposing that doesn't happen, and the worker thread processes the original m_data, and eventually makes its way to Line F, what happens when that Pulse() goes off? Will only the thread waiting on Line C be able to get the lock? Or will it be competing with all the other threads waiting on Line A as well? Essentially, I want to know if Pulse()/Wait() communicate with each other specially "under the hood" or if they are on the same level with lock(). The solution to these problems, if they exist, is obvious of course - just surround SetData() with another lock - say, lock(y). I'm just curious if it's even an issue to begin with.

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• Generics with constraints hierarchy

  - by devoured elysium

  I am currently facing a very disturbing problem: interface IStateSpace<Position, Value> where Position : IPosition // <-- Problem starts here where Value : IValue // <-- and here as I don't { // know how to get away this // circular dependency! // Notice how I should be // defining generics parameters // here but I can't! Value GetStateAt(Position position); void SetStateAt(Position position, State state); } As you'll down here, both IPosition, IValue and IState depend on each other. How am I supposed to get away with this? I can't think of any other design that will circumvent this circular dependency and still describes exactly what I want to do! interface IState<StateSpace, Value> where StateSpace : IStateSpace where Value : IValue { StateSpace StateSpace { get; }; Value Value { get; set; } } interface IPosition { } interface IValue<State> where State : IState { State State { get; } } Basically I have a state space IStateSpace that has states IState inside. Their position in the state space is given by an IPosition. Each state then has one (or more) values IValue. I am simplifying the hierarchy, as it's a bit more complex than described. The idea of having this hierarchy defined with generics is to allow for different implementations of the same concepts (an IStateSpace will be implemented both as a matrix as an graph, etc). Would can I get away with this? How do you generally solve this kind of problems? Which kind of designs are used in these cases? Thanks

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• jQuery change CSS background position and mouseover/mouseout

  - by steelfrog

  I have a menu composed of a single image (e.g., sprites). In order to display the hover image, I simply move the background image down. I'd like this effect to be controlled by jQuery and animated. This is a sample menu item. <ul> <li id="home"><a href="#"></a></li> </ul> This is what I'm toying with. I'm very new to jQuery and am having problems getting the proper selector going. $(document).ready(function(){ $('#home a'); // Set the 'normal' state background position .css( {backgroundPosition: "0 0"} ) // On mouse over, move the background .mouseover(function(){ $(this).stop().animate({backgroundPosition:"(0 -54px)"}, {duration:500}) }) // On mouse out, move the background back .mouseout(function(){ $(this).stop().animate({backgroundPosition:"(0 0)"}, {duration:500}) }) }); Could you point out what I'm doing wrong? I know the selector is probably incorrect but I'm having a hard time figuring out how to manipulate the anchor.

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• install linux guest on windows host using a .iso file on vmserver 2.0

  - by Bob

  I have done this in vmserver 1.0. I set the Cd to point to the .iso file. Then I start the vm and it starts to install. I am on the summary screen. I have created a VM. I go to CD/DVD - edit I change the radio button to Host Medio Then I select ISO Image and Browse. Here is the problem: Then in my browser I get Inventory - Virtual Machine (directory) I don't know where that directory is. I have my ISO's in a folder on my desktop. I can't browse to my desktop. When I try to just put in a path such as c:\mydesktop\mylinuxdirectory\linux1.iso The following problems have been found:OKThe ISO Image File Path must be a valid file path in the format: "[datastore] /path/to/isoimage.iso". so how do I browse to an ISO? I can add the iso after I start the VM, but by then its too late and the VM says no Operating System installed.

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• SSIS - How do I use a resultset as input in a SQL task and get data types right?

  - by thursdaysgeek

  I am trying to merge records from an Oracle database table to my local SQL table. I have a variable for the package that is an Object, called OWell. I have a data flow task that gets the Oracle data as a SQL statment (select well_id, well_name from OWell order by Well_ID), and then a conversion task to convert well_id from a DT_STR of length 15 to a DT_WSTR; and convert well_name from a DT_STR of length 15 to DT_WSTR of length 50. That is then stored in the recordset OWell. The reason for the conversions is the table that I want to add records to has an identity field: SSIS shows well_id as a DT_WSTR of length 15, well_name a DT_WSTR of length 50. I then have a SQL task that connects to the local database and attempts to add records that are not there yet. I've tried various things: using the OWell as a result set and referring to it in my SQL statement. Currently, I have the ResultSet set to None, and the following SQL statment: Insert into WELL (WELL_ID, WELL_NAME) Select OWELL_ID, OWELL_NAME from OWell where OWELL_ID not in (select WELL.WELL_ID from WELL) For Parameter Mapping, I have Paramater 0, called OWell_ID, from my variable User::OWell. Parameter 1, called OWell_Name is from the same variable. Both are set to VARCHAR, although I've also tried NVARCHAR. I do not have a Result set. I am getting the following error: Error: 0xC002F210 at Insert records to FLEDG, Execute SQL Task: Executing the query "Insert into WELL (WELL_ID, WELL_NAME) Select OWELL..." failed with the following error: "An error occurred while extracting the result into a variable of type (DBTYPE_STR)". Possible failure reasons: Problems with the query, "ResultSet" property not set correctly, parameters not set correctly, or connection not established correctly. I don't think it's a data type issue, but rather that I somehow am not using the resultset properly. How, exactly, am I supposed to refer to that recordset in my SQL task, so that I can use the two recordset fields and add records that are missing?

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• SQL Server: Is it possible to prevent SQL Agent from failing a step on error?

  - by Kenneth

  I have a stored procedure that runs custom backups for around 60 SQL servers (mixes 2000 through 2008R2). Occasionally, due to issues outside of my control (backup device inaccessible, network error, etc.) an individual backup on one or two databases will fail. This causes this entire step to fail, which means any subsequent backup commands are not executed and half of the databases on a given server may not be backed up. On the 2005+ boxes I am using TRY/CATCH blocks to manage these problems and continue backing up the remaining databases. On a 2000 server however, for example, I have no way to prevent this error from failing the entire step: Msg 3201, Level 16, State 1, Line 1 Cannot open backup device 'db-diff(\PATH\DB-DIFF-03-16-2010.DIF)'. Operating system error 5(Access is denied.). Msg 3013, Level 16, State 1, Line 1 BACKUP DATABASE is terminating abnormally. I am simply asking if anything like TRY/CATCH is possible in SQL 2000? I realize there are no built in methods for this, so I guess I am looking for some creativity. Even when wrapping each backup (or any failing statement) via sp_executesql the job fails instantly. Example: DECLARE @x INT, @iReturn INT PRINT 'Executing statement that will fail with 208.' EXEC @iReturn = Sp_executesql N'SELECT * from TABLETHATDOESNTEXIST;' PRINT Cast(@iReturn AS NVARCHAR) --In SSMS this return code prints. Executed as a job it fails and aborts before this statement.

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• Better ways to implement a modulo operation (algorithm question)

  - by ryxxui

  I've been trying to implement a modular exponentiator recently. I'm writing the code in VHDL, but I'm looking for advice of a more algorithmic nature. The main component of the modular exponentiator is a modular multiplier which I also have to implement myself. I haven't had any problems with the multiplication algorithm- it's just adding and shifting and I've done a good job of figuring out what all of my variables mean so that I can multiply in a pretty reasonable amount of time. The problem that I'm having is with implementing the modulus operation in the multiplier. I know that performing repeated subtractions will work, but it will also be slow. I found out that I could shift the modulus to effectively subtract large multiples of the modulus but I think there might still be better ways to do this. The algorithm that I'm using works something like this (weird pseudocode follows): result,modulus : integer (n bits) (previously defined) shiftcount : integer (initialized to zero) while( (modulus<result) and (modulus(n-1) != 1) ){ modulus = modulus << 1 shiftcount++ } for(i=shiftcount;i>=0;i++){ if(modulus<result){result = result-modulus} if(i!=0){modulus = modulus << 1} } So...is this a good algorithm, or at least a good place to start? Wikipedia doesn't really discuss algorithms for implementing the modulo operation, and whenever I try to search elsewhere I find really interesting but incredibly complicated (and often unrelated) research papers and publications. If there's an obvious way to implement this that I'm not seeing, I'd really appreciate some feedback.

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• Kohana 3 ORM: How to get data from pivot table? and all other tables for that matter

  - by zenna

  I am trying to use ORM to access data stored, in three mysql tables 'users', 'items', and a pivot table for the many-many relationship: 'user_item' I followed the guidance from http://stackoverflow.com/questions/1946357/kohana-3-orm-read-additional-columns-in-pivot-tables and tried $user = ORM::factory('user',1); $user->items->find_all(); $user_item = ORM::factory('user_item', array('user_id' => $user, 'item_id' => $user->items)); if ($user_item->loaded()) { foreach ($user_item as $pivot) { print_r($pivot); } } But I get the SQL error: "Unknown column 'user_item.id' in 'order clause' [ SELECT user_item.* FROM user_item WHERE user_id = '1' AND item_id = '' ORDER BY user_item.id ASC LIMIT 1 ]" Which is clearly erroneous because Kohana is trying to order the elements by a column which doesn't exist: user_item.id. This id doesnt exist because the primary keys of this pivot table are the foreign keys of the two other tables, 'users' and 'items'. Trying to use: $user_item = ORM::factory('user_item', array('user_id' => $user, 'item_id' => $user->items)) ->order_by('item_id', 'ASC'); Makes no difference, as it seems the order_by() or any sql queries are ignored if the second argument of the factory is given. Another obvious error with that query is that the item_id = '', when it should contain all the elements. So my question is how can I get access to the data stored in the pivot table, and actually how can I get access to the all items held by a particular user as I even had problems with that? Thanks

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• Fulltext search on many tables

  - by Rob

  I have three tables, all of which have a column with a fulltext index. The user will enter search terms into a single text box, and then all three tables will be searched. This is better explained with an example: documents doc_id name FULLTEXT table2 id doc_id a_field FULLTEXT table3 id doc_id another_field FULLTEXT (I realise this looks stupid but that's because I've removed all the other fields and tables to simplify it). So basically I want to do a fulltext search on name, a_field and another_field, and then show the results as a list of documents, preferably with what caused that document to be found, e.g. if another_field matched, I would display what another_field is. I began working on a system whereby three fulltext search queries are performed and the results inserted into a table with a structure like: search_results table_name row_id score (This could later be made to cache results for a few days with e.g. a hash of the search terms). This idea has two problems. The first is that the same document can be in the search results up to three times with different scores. Instead of that, if the search term is matched in two tables, it should have one result, but a higher score. The second is that parsing the results is difficult. I want to display a list of documents, but I don't immediately know the doc_id without a join of some kind; however the table to join to is dependant on the table_name column, and I'm not sure how to accomplish that. Wanting to search multiple related tables like this must be a common thing, so I guess what I'm asking is am I approaching this in the right way? Can someone tell me the best way of doing it please.

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• How do you save images to a Blackberry device via HttpConnection?

  - by Kai

  My script fetches xml via httpConnection and saves to persistent store. No problems there. Then I loop through the saved data to compose a list of image url's to fetch via queue. Each of these requests calls the httpConnection thread as so ... public synchronized void run() { HttpConnection connection = (HttpConnection)Connector.open("http://www.somedomain.com/image1.jpg"); connection.setRequestMethod("GET"); String contentType = connection.getHeaderField("Content-type"); InputStream responseData = connection.openInputStream(); connection.close(); outputFinal(responseData, contentType); } public synchronized void outputFinal(InputStream result, String contentType) throws SAXException, ParserConfigurationException, IOException { if(contentType.startsWith("text/")) { // bunch of xml save code that works fine } else if(contentType.equals("image/png") || contentType.equals("image/jpeg") || contentType.equals("image/gif")) { // how to save images here? } else { //default } } What I can't find any good documentation on is how one would take the response data and save it to an image stored on the device. Maybe I just overlooked something very obvious. Any help is very appreciated. Thanks

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• python NameError: name '<anything>' is not defined (but it is!)

  - by BenjaminGolder

  Note: Solved. It turned out that I was importing a previous version of the same module. It is easy to find similar topics on StackOverflow, where someone ran into a NameError. But most of the questions deal with specific modules and the solution is often to update the module. In my case, I am trying to import a function from a module that I wrote myself. The module is named InfraPy, and it is definitely on sys.path. One particular function (called listToText) in InfraPy returns a NameError, but only when I try to import it into another script. Inside InfraPy, under if __name__=='__main__':, the listToText function works just fine. From InfraPy I can import other functions with no problems. Including from InfraPy import * in my script does not return any errors until I try to use the listToText function. How can this occur? How can importing one particular function return a NameError, while importing all the other functions in the same module works fine? Using python 2.6 on MacOSX 10.6, also encountered the same error running the script on Windows 7, using IronPython 2.6 for .NET 4.0 Thanks. If there are other details you think would be helpful in solving this, I'd be happy to provide them. As requested, here is the function definition inside of InfraPy: def listToText(inputList, folder=None, outputName='list.txt'): ''' Creates a text file from a list (with each list item on a separate line). May be placed in any given folder, but will otherwise be created in the working directory of the python interpreter. ''' fname = outputName if folder != None: fname = folder+'/'+fname f = open(fname, 'w') for file in inputList: f.write(file+'\n') f.close() This function is defined above and outside of if __name__=='__main__': I've tried moving InfraPy around in relation to the script. The most baffling situation is that when InfraPy is in the same folder as the script, and I import using from InfraPy import listToText, I receive this error: NameError: name listToText is not defined. Again, the other functions import fine, they are all defined outside of if __name__=='__main__': in InfraPy.

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• How to not pass around the container when using IoC in Winforms

  - by L2Type

  I'm new to the world of IoC and having a problem with implementing it in a Winforms application. I have an extremely basic application Winform application that uses MVC, it is one controller that does all the work and a working dialog (obviously with a controller). So I load all my classes in to my IoC container in program.cs and create the main form controller using the container. But this is where I am having problems, I only want to create the working dialog controller when it's used and inside a using statement. At first I passed in the container but I've read this is bad practice and more over the container is a static and I want to unit test this class. So how do you create classes in a unit test friendly way without passing in the container, I was considering the abstract factory pattern but that alone would solve my problem without using the IoC. I'm not using any famous framework, I borrowed a basic one from this blog post http://www.kenegozi.com/Blog/2008/01/17/its-my-turn-to-build-an-ioc-container-in-15-minutes-and-33-lines.aspx How do I do this with IoC? Is this the wrong use for IoC?

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• LINQ Datacontext Disposal Issues

  - by Refracted Paladin

  I am getting a Cannot access object: DataContext after it's been disposed in the below DAL method. I thought that I would be okay calling dispose there. result is an IEnumurable and I thought it was IQueryable that caused these kinds of problems. What am I doing wrong? How SHOULD I be disposing of my DataContext. Is there something better to be returning then a DataTable? This is a Desktop app that points at SQL 2005. Example method that causes this error -- public static DataTable GetEnrolledMembers(Guid workerID) { var DB = CmoDataContext.Create(); var AllEnrollees = from enrollment in DB.tblCMOEnrollments where enrollment.CMOSocialWorkerID == workerID || enrollment.CMONurseID == workerID join supportWorker in DB.tblSupportWorkers on enrollment.EconomicSupportWorkerID equals supportWorker.SupportWorkerID into workerGroup from worker in workerGroup.DefaultIfEmpty() select new { enrollment.ClientID, enrollment.CMONurseID, enrollment.CMOSocialWorkerID, enrollment.EnrollmentDate, enrollment.DisenrollmentDate, ESFirstName = worker.FirstName, ESLastName = worker.LastName, ESPhone = worker.Phone }; var result = from enrollee in AllEnrollees.AsEnumerable() where (enrollee.DisenrollmentDate == null || enrollee.DisenrollmentDate > DateTime.Now) //let memberName = BLLConnect.MemberName(enrollee.ClientID) let lastName = BLLConnect.MemberLastName(enrollee.ClientID) let firstName = BLLConnect.MemberFirstName(enrollee.ClientID) orderby enrollee.DisenrollmentDate ascending, lastName ascending select new { enrollee.ClientID, //MemberName = memberName, LastName = lastName, FirstName = firstName, NurseName = BLLAspnetdb.NurseName(enrollee.CMONurseID), SocialWorkerName = BLLAspnetdb.SocialWorkerName(enrollee.CMOSocialWorkerID), enrollee.EnrollmentDate, enrollee.DisenrollmentDate, ESWorkerName = enrollee.ESFirstName + " " + enrollee.ESLastName, enrollee.ESPhone }; DB.Dispose(); return result.CopyLinqToDataTable(); } partial class where I create the DataContext -- partial class CmoDataContext { public static bool IsDisconnectedUser { get { return Settings.Default.IsDisconnectedUser; } } public static CmoDataContext Create() { var cs = IsDisconnectedUser ? Settings.Default.CMOConnectionString : Settings.Default.Central_CMOConnectionString; return new CmoDataContext(cs); }

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• Google Code Jam 2010 Large DataSets Take Too Long to Submit

  - by Travis

  Hey Guys, I'm participating in the 2010 code jam and I solved two of the problems for the small data sets, but I'm not even close to solving the large data sets in the 8 minute time frame. I'm wondering if anyone out there has solved the large data set: What hardware were you running on? What language were you running on? What performance tuning techniques did you do on your code to run as fast as possible? I'm writing the solutions in Ruby, which is not my day to day language, and executing them on my Macbook Pro. My solutions for problem A and problem C are on github at http://github.com/tjboudreaux/codejam2010. I'd appreciate any suggestions that you may have. FWIW, I have alot of experience in C++ from college, my primary language is PHP, and my "sandbox" language is Ruby. Was I just a bit ambitious by taking a shot at this in Ruby, not knowing where the language struggles for performance, or does anyone see anything that's a redflag as to why I can't complete the large dataset in time to submit.

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• Stream Reuse in C#

  - by MikeD

  I've been playing around with what I thought was a simple idea. I want to be able to read in a file from somewhere (website, filesystem, ftp), perform some operations on it (compress, encrypt, etc.) and then save it somewhere (somewhere may be a filesystem, ftp, or whatever). It's a basic pipeline design. What I would like to do is to read in the file and put it onto a MemoryStream, then perform the operations on the data in the MemoryStream, and then save that data in the MemoryStream somewhere. I was thinking I could use the same Stream to do this but run into a couple of problems: Everytime I use a StreamWriter or StreamReader I need to close it and that closes the stream so that I cannot use it anymore. That seems like there must be some way to get around that. Some of these files may be big and so I may run out of memory if I try to read the whole thing in at once. I was hoping to be able to spin up each of the steps as separate threads and have the compression step begin as soon as there is data on the stream, and then as soon as the compression has some compressed data available on the stream I could start saving it (for example). Is anything like this easily possible with the C# Streams? ANyone have thoughts as to how to accomplish this best? Thanks, Mike

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• When should I be cautious using about data binding in .NET?

  - by Ben McCormack

  I just started working on a small team of .NET programmers about a month ago and recently got in a discussion with our team lead regarding why we don't use databinding at all in our code. Every time we work with a data grid, we iterate through a data table and populate the grid row by row; the code usually looks something like this: Dim dt as DataTable = FuncLib.GetData("spGetTheData ...") Dim i As Integer For i = 0 To dt.Rows.Length - 1 '(not sure why we do not use a for each here)' gridRow = grid.Rows.Add() gridRow(constantProductID).Value = dt("ProductID").Value gridRow(constantProductDesc).Value = dt("ProductDescription").Value Next '(I am probably missing something in the code, but that is basically it)' Our team lead was saying that he got burned using data binding when working with Sheridan Grid controls, VB6, and ADO recordsets back in the nineties. He's not sure what the exact problem was, but he remembers that binding didn't work as expected and caused him some major problems. Since then, they haven't trusted data binding and load the data for all their controls by hand. The reason the conversation even came up was because I found data binding to be very simple and really liked separating the data presentation (in this case, the data grid) from the in-memory data source (in this case, the data table). "Loading" the data row by row into the grid seemed to break this distinction. I also observed that with the advent of XAML in WPF and Silverlight, data-binding seems like a must-have in order to be able to cleanly wire up a designer's XAML code with your data. When should I be cautious of using data-binding in .NET?

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• Encrypting an id in an URL in ASP.NET MVC

  - by Chuck Conway

  I'm attempting to encode the encrypted id in the Url. Like this: http://www.calemadr.com/Membership/Welcome/9xCnCLIwzxzBuPEjqJFxC6XJdAZqQsIDqNrRUJoW6229IIeeL4eXl5n1cnYapg+N However, it either doesn't encode correctly and I get slashes '/' in the encryption or I receive and error from IIS: The request filtering module is configured to deny a request that contains a double escape sequence. I've tried different encodings, each fails: HttpUtility.HtmlEncode HttpUtility.UrlEncode HttpUtility.UrlPathEncode HttpUtility.UrlEncodeUnicode Update The problem was I when I encrypted a Guid and converted it to a base64 string it would contain unsafe url characters . Of course when I tried to navigate to a url containing unsafe characters IIS(7.5/ windows 7) would blow up. Url Encoding the base64 encrypted string would raise and error in IIS (The request filtering module is configured to deny a request that contains a double escape sequence.). I'm not sure how it detects double encoded strings but it did. After trying the above methods to encode the base64 encrypted string. I decided to remove the base64 encoding. However this leaves the encrypted text as a byte[]. I tried UrlEncoding the byte[], it's one of the overloads hanging off the httpUtility.Encode method. Again, while it was URL encoded, IIS did not like it and served up a "page not found." After digging around the net I came across a HexEncoding/Decoding class. Applying the Hex Encoding to the encrypted bytes did the trick. The output is url safe. On the other side, I haven't had any problems with decoding and decrypting the hex strings.

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• OpenGL ES, UIView and Status Bar mess

  - by sfider

  I have iPhone (iPhoneOS 3.x) OpenGL ES app that: can be in landscape/portrait orientation can be with/without status bar shown I do this by changing status bar orientation and hidden state, then updating OpenGL view frame so it won't overlap status bar and setting projection matrix appropriately. OpenGL view is in portrait orientation at all time. View controller's shouldAutorotateToInterfaceOrientation: method returns false always, so the status bar won't start autorotating when app is in landscape mode. The problem I have is that I want to use some other UIViews, like: UIWebView, MFMailComposeView, MPMediaPicker. I could show them as modals, but this this have some drawbacks: views will always show in portrait orientation, even if they support landscape orientation views will not autorotate, even if they support it What I do is I take OpenGL view of the window with removeFromSuperview, set transform to the other view so it will be in portrait/landscape orientation when it shows up and place the other view on the window with addSubview:. This works fine without the status bar, but with it there are some problems I cannot work out: MPMediaPicker is sized to fit under status bar, but it slides under it anyway MFMailComposeView does not show navigation bar until it autorotates on device orientation change Does anyone has an idea how can I get it to work?

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• Extracting [] elements from form collection - mvc - should use icollection but have mix of types

  - by bergin

  hi there. have looked at Phil Haacks project on books at http://haacked.com/archive/2008/10/23/model-binding-to-a-list.aspx which has been useful, but I have a mix of data types. I use a modelview so that i can have a mix of objects, in this case: Order (ie order.id, order.date etc), Customer, SoilSamplingOrder and a list of SoilSamplingSubJobs which is like this [0].id, [0].field, [1].id, [1].field etc Perhaps I should be using ICollection instead of List? I had problems getting UpdateModel to work so I used an extract from collection method. the first 4 method calls : orderRepository.FindOrder(id); etc give the model the original to be edited. but after this point i'm a little lost in how to update the subjobs. I hope i have delineated enough to make sense of the problem. [HttpPost] public ActionResult Edit(int id, FormCollection collection) { Order order = orderRepository.FindOrder(id); Customer cust = orderRepository.FindCustomer(order.customer_id); IList<SoilSamplingSubJob> sssj = orderRepository.FindSubOrders(id); SoilSamplingOrder sso = orderRepository.FindSoilSampleOrder(id); try { UpdateModel(order, collection.ToValueProvider()); UpdateModel(cust, collection.ToValueProvider()); UpdateModel(sso, collection.ToValueProvider()); IList<SoilSamplingSubJob> sssjs = orderRepository.extractSSSJ(collection); foreach (var sj in sssjs) UpdateModel(sso, collection.ToValueProvider()); orderRepository.Save(); return RedirectToAction("Details", new { id=order.order_id}); } catch { return View(); } }

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• SQL Server 2000 intermittent connection exceptions on production server - specific environment probl

  - by StickyMcGinty

  We've been having intermittent problems causing users to be forcibly logged out of out application. Our set-up is ASP.Net/C# web application on Windows Server 2003 Standard Edition with SQL Server 2000 on the back end. We've recently performed a major product upgrade on our client's VMWare server (we have a guest instance dedicated to us) and whereas we had none of these issues with the previous release the added complexity that the new upgrade brings to the product has caused a lot of issues. We are also running SQL Server 2000 (build 8.00.2039, or SP4) and the IIS/ASP.NET (.Net v2.0.50727) application on the same box and connecting to each other via a TCP/IP connection. Primarily, the exceptions being thrown are: System.IndexOutOfRangeException: Cannot find table 0. System.ArgumentException: Column 'password' does not belong to table Table. [This exception occurs in the log in script, even though there is clearly a password column available] System.InvalidOperationException: There is already an open DataReader associated with this Command which must be closed first. [This one is occurring very regularly] System.InvalidOperationException: This SqlTransaction has completed; it is no longer usable. System.ApplicationException: ExecuteReader requires an open and available Connection. The connection's current state is connecting. System.Data.SqlClient.SqlException: Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding. And just today, for the first time: System.Web.UI.ViewStateException: Invalid viewstate. We have load tested the app using the same number of concurrent users as the production server and cannot reproduce these errors. They are very intermittent and occur even when there are only 8/9/10 user connections. My gut is telling me its ASP.NET - SQL Server 2000 connection issues.. We've pretty much ruled out code-level Data Access Layer errors at this stage (we've a development team of 15 experienced developers working on this) so we think its a specific production server environment issue.

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