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• Is this a good way to expose generic base class methods through an interface?

  - by Nate Heinrich

  I am trying to provide an interface to an abstract generic base class. I want to have a method exposed on the interface that consumes the generic type, but whose implementation is ultimately handled by the classes that inherit from my abstract generic base. However I don't want the subclasses to have to downcast to work with the generic type (as they already know what the type should be). Here is a simple version of the only way I can see to get it to work at the moment. public interface IFoo { void Process(Bar_base bar); } public abstract class FooBase<T> : IFoo where T : Bar_base { abstract void Process(T bar); // Explicit IFoo Implementation void IFoo.Process(Bar_base bar) { if (bar == null) throw new ArgumentNullException(); // Downcast here in base class (less for subclasses to worry about) T downcasted_bar = bar as T; if (downcasted_bar == null) { throw new InvalidOperationException( string.Format("Expected type '{0}', not type '{1}'", T.ToString(), bar.GetType().ToString()); } //Process downcasted object. Process(downcasted_bar); } } Then subclasses of FooBase would look like this... public class Foo_impl1 : FooBase<Bar_impl1> { void override Process(Bar_impl1 bar) { //No need to downcast here! } } Obviously this won't provide me compile time Type Checking, but I think it will get the job done... Questions: 1. Will this function as I think it will? 2. Is this the best way to do this? 3. What are the issues with doing it this way? 4. Can you suggest a different approach? Thanks!

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• Speed vs security vs compatibility over methods to do string concatenation in Python

  - by Cawas

  Similar questions have been brought (good speed comparison there) on this same subject. Hopefully this question is different and updated to Python 2.6 and 3.0. So far I believe the faster and most compatible method (among different Python versions) is the plain simple + sign: text = "whatever" + " you " + SAY But I keep hearing and reading it's not secure and / or advisable. I'm not even sure how many methods are there to manipulate strings! I could count only about 4: There's interpolation and all its sub-options such as % and format and then there's the simple ones, join and +. Finally, the new approach to string formatting, which is with format, is certainly not good for backwards compatibility at same time making % not good for forward compatibility. But should it be used for every string manipulation, including every concatenation, whenever we restrict ourselves to 3.x only? Well, maybe this is more of a wiki than a question, but I do wish to have an answer on which is the proper usage of each string manipulation method. And which one could be generally used with each focus in mind (best all around for compatibility, for speed and for security). Thanks.

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• Autorotation and multiple view controllers

  - by alku83

  I'm creating an iPad application which should only work in portrait and portait upsidedown modes. For performance reasons in my applicationDidFinishLaunching method I'm creating several viewControllers, and adding them to my main window as subviews. I then hide the ones I don't want to see straight away. There is no tab bar or navigation controller. My problem is that only the first viewController seems to be receiving the rotate calls. I have verified this by swapping around the order in which I add the subviews to the main window and NSLog's. Is there some way I can force all the controllers to receive the calls? Some of my views are designed to lay over the top of another view, but this behind view will not always be the same one - so it seems to make sense to have the overlay view in a separate view controller. Am I doing something fundamentally wrong, and that's why it's not behaving as I would expect? EDIT: The accepted answer for this question seems to indicate the exact problem I'm facing: http://stackoverflow.com/questions/548142/uiviewcontroller-rotate-methods

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• Self-referencing tables in Linq2Sql

  - by J-Man

  Hi, I've seen a lot of questions on self-referencing tables in Linq2Sql and how to eagerly load all child records for a particular root object. I've implemented a temporary solution by accessing all underlying properties, but you can see that this doesn't do the performance any good. The thing is though, that all records are correlated with each-other using a correlation GUID. Example below: RootElement - Id: 1 - ParentId: null - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD ChildElement1 - Id: 2 - ParentId: 1 - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD ChildElement2 - Id: 3 - ParentId: 2 - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD ChildElement1 - Id: 4 - ParentId: 2 - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD In my case, I do have access to the correlationId, so I can retrieve all of my records by performing the following query: from element in db.Elements where element.CorrelationId == '4D68E512-4B55-44f4-BA5A-174B630A03DD' select element; But, of course, I want these elements associated with each other by executing this query: from element in db.Elements where element.CorrelationId == '4D68E512-4B55-44f4-BA5A-174B630A03DD' && element.ParentId == null select element; My question is: is it possible to combine the results the first query as some sort of 'caching mechanism' for the query where I get the root element? Thanks for the input. J.

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• Help with Jquery + Masonry Plugin: How to expand/collapse boxes to reveal content

  - by Jam

  I'm using the masonry jquery plugin on a project: (http://desandro.com/resources/jquery-masonry) Basically I have a set of boxes (thumbnails) in a grid. When one is clicked, I want it to expand to a larger size to show more content (additional images and text). I'm struggling with how to make the thumbnail dissappear and then have new content appear in the expanded box. I don't know how to make the new content appear or where to store it on my page--and it needs to have a close button? The creator of the plugin gave me a quick tip for the expanding part, but the code I'm using has a set height and width and I want them to be variable depending on how much content is in the expanded state. Here's my jquery code so far: http://pastie.org/1002101 This is a similar example of the behaviour I want to achieve (except my boxes will have have varying expanded sizes): (http://www.learnsomethingeveryday.co.uk) You'll also notice from that example that it only allows 1 box to be expanded at a time--I would also like to have that functionality. Sorry for all the questions--I'm pretty new to jquery, any help would be amazing!

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• Multithreading and Interrupts

  - by Nicholas Flynt

  I'm doing some work on the input buffers for my kernel, and I had some questions. On Dual Core machines, I know that more than one "process" can be running simultaneously. What I don't know is how the OS and the individual programs work to protect collisions in data. There are two things I'd like to know on this topic: (1) Where do interrupts occur? Are they guaranteed to occur on one core and not the other, and could this be used to make sure that real-time operations on one core were not interrupted by, say, file IO which could be handled on the other core? (I'd logically assume that the interrupts would happen on the 1st core, but is that always true, and how would you tell? Or perhaps does each core have its own settings for interrupts? Wouldn't that lead to a scenario where each core could react simultaneously to the same interrupt, possibly in different ways?) (2) How does the dual core processor handle opcode memory collision? If one core is reading an address in memory at exactly the same time that another core is writing to that same address in memory, what happens? Is an exception thrown, or is a value read? (I'd assume the write would work either way.) If a value is read, is it guaranteed to be either the old or new value at the time of the collision? I understand that programs should ideally be written to avoid these kinds of complications, but the OS certainly can't expect that, and will need to be able to handle such events without choking on itself.

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• advanced Visual Studio kung-fu test -- Calling functions from the Immediate Window during debugging

  - by kizzx2

  I see some related questions have been asked, but they're either too advanced for me to grasp or lacking a step-by-step guide from start to finish (most of them end up being insider talk of their own experiment results). OK here it is, given this simple program: #include <stdio.h> #include <string.h> int main() { FILE * f; char buffer[100]; memset(buffer, 0, 100); fun(); f = fopen("main.cpp", "r"); fread(buffer, 1, 99, f); printf(buffer); fclose(f); return 0; } What it does is basically print itself (assume file name is main.cpp). Question How can I have it print another file, say foobar.txt without modifying the source code? It has something to do with running it through VS's, stepping through the functions and hijacking the FILE pointer right before fread() is called. No need to worry about leaking resources by calling fclose(). I tried the simple f = fopen("foobar.txt", "r") which gave CXX0017: Error: symbol "fopen" not found Any ideas? Edit I found out the solution accidentally on Debugging Mozilla on Windows FAQ. The correct command to put into the Immediate Window is f = {,,MSVCR100D}fopen("foo.txt", "r") However, it doesn't really answer this question: I still don't understand what is going on here. How to systematically find out the {,,MSVCR100D} part for any given method? I know the MSVCR version changes from system to system. How can I find that out? Could anyone explain the curly brace syntax, especially, what are those two commas doing there? Are there more hidden gems using this syntax?

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• Vertically center a fluid image in a fluid container

  - by Ferdy

  I certainly do not want to add to the pile of vertical alignments CSS questions, but I've spent hours trying to find a solution to no avail yet. Here's the situation: I am building a slideshow gallery of images. I want the images to be displayed as large as the user's window allows. So I have this outer placeholder: <section class="photo full"> (Yes, I'm using HTML5 elements). Which has the following CSS: section.photo.full { display:inline-block; width:100%; height:100%; position:absolute; overflow:hidden; text-align:center; } Next, the image is placed inside it. Depending on the orientation of the image, I set either the width or height to 75%, and the other axis to auto: $wide = $bigimage['width'] >= $bigimage['height'] ? true: false; ?> <img src="<?= $bigimage['url'] ?>" width="<?= $wide? "75%" : "auto"?>" height="<?= $wide? "auto" : "75%"?>"/> So, we have a fluid outer container, with inside a fluid image. The horizontal centering of the image works, yet I cannot seem to find a way to vertically center the image within it's container. I have researched centering methods but most assume either the container or image has a known width or height. Then there is the display:table-cell method, which does not seem to work for me either. I'm stuck. I'm looking for a CSS solution, but am open to js solutions too.

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• What are the reasons to store documents into DBMS when using Alfresco DMS

  - by Julia

  Hello guys! I have interview for an internship with company that wants to implement document management system and they are considering on the first place open source solutions, their top choice being Alfresco, but decision is still not final, part of my work there would be to investigate is Alfresco the best solution. What I have seen from project description, is that they would implement Alfresco with MySQL database, and not to use DBMS just for document metadata and indexing, but they actually want to store documents inside. By company profile, type of documents would be mostly PDF and .doc, not images. I have researched a bit, and I have read all the topics here related to storing files into the database, not to duplicate a question. So from what I understand, storing BLOBS is generally not recomendable, and by the profile of the company and their legal obligations with archiving, I see they will have to store larger amount of docs. I would like to be ready as much as I can for the interview and that is why I would like your opinion on these questions: 1) What will be your reasons for deciding to store documents into the DBMS, (especially having in mind that you are installing Alfresco, which stores files in the FS)??? 2) Do you have any experiences with storing documents into the MySQL database specifically??? All the help is very much appreciated, I am really excited about interview and really want this internship, so this is one of things i really want to understand before!! Thank you!!!!

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• Can I spead out a long running stored proc accross multiple CPU's?

  - by Russ

  [Also on SuperUser - http://superuser.com/questions/116600/can-i-spead-out-a-long-running-stored-proc-accross-multiple-cpus] I have a stored procedure in SQL server the gets, and decrypts a block of data. ( Credit cards in this case. ) Most of the time, the performance is tolerable, but there are a couple customers where the process is painfully slow, taking literally 1 minute to complete. ( Well, 59377ms to return from SQL Server to be exact, but it can vary by a few hundred ms based on load ) When I watch the process, I see that SQL is only using a single proc to perform the whole process, and typically only proc 0. Is there a way I can change my stored proc so that SQL can multi-thread the process? Is it even feasible to cheat and to break the calls in half, ( top 50%, bottom 50% ), and spread the load, as a gross hack? ( just spit-balling here ) My stored proc: USE [Commerce] GO /****** Object: StoredProcedure [dbo].[GetAllCreditCardsByCustomerId] Script Date: 03/05/2010 11:50:14 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO ALTER PROCEDURE [dbo].[GetAllCreditCardsByCustomerId] @companyId UNIQUEIDENTIFIER, @DecryptionKey NVARCHAR (MAX) AS SET NoCount ON DECLARE @cardId uniqueidentifier DECLARE @tmpdecryptedCardData VarChar(MAX); DECLARE @decryptedCardData VarChar(MAX); DECLARE @tmpTable as Table ( CardId uniqueidentifier, DecryptedCard NVarChar(Max) ) DECLARE creditCards CURSOR FAST_FORWARD READ_ONLY FOR Select cardId from CreditCards where companyId = @companyId and Active=1 order by addedBy desc --2 OPEN creditCards --3 FETCH creditCards INTO @cardId -- prime the cursor WHILE @@Fetch_Status = 0 BEGIN --OPEN creditCards DECLARE creditCardData CURSOR FAST_FORWARD READ_ONLY FOR select convert(nvarchar(max), DecryptByCert(Cert_Id('Oh-Nay-Nay'), EncryptedCard, @DecryptionKey)) FROM CreditCardData where cardid = @cardId order by valueOrder OPEN creditCardData FETCH creditCardData INTO @tmpdecryptedCardData -- prime the cursor WHILE @@Fetch_Status = 0 BEGIN print 'CreditCardData' print @tmpdecryptedCardData set @decryptedCardData = ISNULL(@decryptedCardData, '') + @tmpdecryptedCardData print '@decryptedCardData' print @decryptedCardData; FETCH NEXT FROM creditCardData INTO @tmpdecryptedCardData -- fetch next END CLOSE creditCardData DEALLOCATE creditCardData insert into @tmpTable (CardId, DecryptedCard) values ( @cardId, @decryptedCardData ) set @decryptedCardData = '' FETCH NEXT FROM creditCards INTO @cardId -- fetch next END select CardId, DecryptedCard FROM @tmpTable CLOSE creditCards DEALLOCATE creditCards

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• how to keep a nativewindow on top

  - by Freddy Rios

  I need to keep a NativeWindow I am creating on top of the main window of the application. Currently I am using alwaysInFront = true, which is not limited to the windows in the application. I can successfully synchronize the minimize/restore/move/resize actions, so the top window behaves appropriately in those cases. Even though using this option has the drawback that if I alt-tab to other application the window goes on top of the other application. Because of the above I am trying to get it to work without using the alwaysInFront. I have tried using orderInFrontOf and orderToFront, which gets it in place but when I click an area in the main window the top one becomes hidden i.e. air makes it the top one. I have tried capturing activate/deactivate events but it only happens on the first click, so on the second click the top window becomes hidden again. I also tried making the top window active when the main one becomes active, but that causes the main one to loose focus and I can't click on anything. Ps. I am doing this to improve the behavior of a HTMLOverlay I am using - see http://stackoverflow.com/questions/1044927/flex-air-htmlloader-blank-pop-up-window-when-flash-content-is-loaded/1077738#1077738

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• Efficient cron job utilizing Zend_Mail_Storage_Imap.

  - by fireeyedboy

  I'm new to the IMAP protocol and Zend_Mail_Storage and I'm writing a small php script for a cron job that should regularly poll an IMAP account and check for new messages, and send an e-mail if new messages have arrived. As you can imagine, I want to only poll the IMAP account for relevant messages, and I only want to send a new e-mail if new messages have arrived since the last polled new message. So I thought of keeping track of the last message I polled with some unique identifier for a message. But I'm a bit uncertain about whether the methods I want to utilize for this do what I expect them to do though. So my questions are: Does the iterator position of Zend_Mail_Storage_Imap actually resemble some IMAP unique identifier for messages, or is it simply only and internal position of Zend_Mail_Storage_Abstract? For instance, if I tell it to seek() to message 5 (which I stored from an earlier session) will it indeed seek to the appropriate message on the IMAP server, even if for instance messages have been deleted since last session? Would keeping track of this latest polled message id in a file suffice for a cron job that, say, polls the account every 5 or 10 minutes? Or is this too naive, and should I be using a database for instance. Or is there maybe a much easier way to keep track of such state with Zend_Mail_Storage_Abstract? Also, do I need to poll every IMAP folder? Or is everything accumulated when I poll INBOX? If you could shed some light on any of these matters, I'ld appreciate it. Thanks in advance.

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• Using phpFlickr, how would one display the primary photo from each photoset?

  - by Michael

  Referring to this question: http://stackoverflow.com/questions/2561475/flickr-phpflickr-api how would you display a primary photo from a photoset rather than all photos and photosets? this is the code I have so far: photosets_getList($user); ? <?php $photoset_id = $ph_set['id']; $photos = $f->photosets_getPhotos($photoset_id); foreach ($photos['photoset']['photo'] as $photo): ?> <?php if($parentID == $ph_set['parent']): ?> <a rel="lightbox[album<?=$count;?>]" href="<?= $f->buildPhotoURL($photo, 'medium') ?>" title="<?= $photo['title'] ?>"> <?php endif;?> <img src="<?= $f->buildPhotoURL($photo, 'square') ?>" alt="<?= $photo['title'] ?>" width="75" height="75" title="<?= $photo['title'] ?>" /> <h3><?=$ph_set['title']?></h3> <?php if($parentID == $ph_set['parent']): ?> </a> </div> <?php endif;?>

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• Looping through a SimpleXML object, or turning the whole thing into an array.

  - by Coffee Cup

  I'm trying to work out how to iterate though a returned SimpleXML object. I'm using a toolkit called Tarzan AWS, which connects to Amazon Web Services (SimpleDB, S3, EC2, etc). I'm specifically using SimpleDB. I can put data into the Amazon SimpleDB service, and I can get it back. I just don't know how to handle the SimpleXML object that is returned. The Tarzan AWS documentation says this: Look at the response to navigate through the headers and body of the response. Note that this is an object, not an array, and that the body is a SimpleXML object. Here's a sample of the returned SimpleXML object: [body] = SimpleXMLElement Object ( [QueryWithAttributesResult] = SimpleXMLElement Object ( [Item] = Array ( [0] = SimpleXMLElement Object ( [Name] = message12413344443260 [Attribute] = Array ( [0] = SimpleXMLElement Object ( [Name] = active [Value] = 1 ) [1] = SimpleXMLElement Object ( [Name] = user [Value] = john ) [2] = SimpleXMLElement Object ( [Name] = message [Value] = This is a message. ) [3] = SimpleXMLElement Object ( [Name] = time [Value] = 1241334444 ) [4] = SimpleXMLElement Object ( [Name] = id [Value] = 12413344443260 ) [5] = SimpleXMLElement Object ( [Name] = ip [Value] = 10.10.10.1 ) ) ) [1] = SimpleXMLElement Object ( [Name] = message12413346907303 [Attribute] = Array ( [0] = SimpleXMLElement Object ( [Name] = active [Value] = 1 ) [1] = SimpleXMLElement Object ( [Name] = user [Value] = fred ) [2] = SimpleXMLElement Object ( [Name] = message [Value] = This is another message ) [3] = SimpleXMLElement Object ( [Name] = time [Value] = 1241334690 ) [4] = SimpleXMLElement Object ( [Name] = id [Value] = 12413346907303 ) [5] = SimpleXMLElement Object ( [Name] = ip [Value] = 10.10.10.2 ) ) ) ) So what code do I need to get through each of the object items? I'd like to loop through each of them and handle it like a returned mySQL query. For example, I can query SimpleDB and then loop though the SimpleXML so I can display the results on the page. Alternatively, how do you turn the whole shebang into an array? I'm new to SimpleXML, so I apologise if my questions aren't specific enough.

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• Grails validation problems with sets of data: only getting one error message for all errors in a set

  - by Matt

  Hi, I'm trying to validate a domain class that has a number of subsets. class IebeUser { ... static hasMany = [openUserAnswers:OpenUserAnswer, closedUserAnswers:ClosedUserAnswer] } class OpenUserAnswer { OpenQuestion openQuestion String text static belongsTo = [user:IebeUser] static constraints = { openQuestion(nullable:false) text(blank:false) } } class ClosedUserAnswer { ClosedQuestion closedQuestion ClosedAnswer answer static belongsTo = [user:IebeUser] static constraints = { closedQuestion(nullable:false) answer(nullable:false) } } A closed question has a set of predefined answers and an open question lets the user enter a freeform answer. All is well until I come to validate the object after entry in a form: params: [closedUserAnswers[0].answer.id:, closedUserAnswers[0]:[answer:[id:], answer.id:], password:dfgdfgdf, openUserAnswers[0].text:gdfgdfgdfg, openUserAnswers[0]:[text:gdfgdfgdfg], _isOptedOut:, create:Continue, username:gdfgdfggdf, email:[email protected], closedUserAnswers[1].answer.id:, closedUserAnswers[1]:[answer:[id:], answer.id:], openUserAnswers[1].text:, openUserAnswers[1]:[text:], firstName:dfgdf, lastName:gdfgdfgd, action:save, controller:main] The key bits being: closedUserAnswers[0].answer.id:, closedUserAnswers[0]:[answer:[id:] closedUserAnswers[1].answer.id:, closedUserAnswers[1]:[answer:[id:] openUserAnswers[1].text:, openUserAnswers[1]:[text:] In my tests I have two objects of type closedUserAnswers and two of openUserAnswers. But when I call validation on IebeUser I only get validation errors for the closedUserAnswers or the openUserAnswers as a whole. I don't get validation errors for each object with a problem which is what I need. I really need an error per instance. Does anyone know what I'm doing wrong? Even when I call the validate method against each closedUserAnswer/openUserAnswer I still only get one per type. Here are my errors. Sorry for all the code, but thought I'd include as much of the code as possible so that it makes sense. Field error in object 'uk.co.cascaid.iebe.IebeUser' on field 'openUserAnswers.text': rejected value []; codes [uk.co.cascaid.iebe.OpenUserAnswer.text.blank.error.uk.co.cascaid.iebe.IebeUser.openUserAnswers.text,uk.co.cascaid.iebe.OpenUserAnswer.text.blank.error.openUserAnswers.text,uk.co.cascaid.iebe.OpenUserAnswer.text.blank.error.text,uk.co.cascaid.iebe.OpenUserAnswer.text.blank.error,openUserAnswer.text.blank.error.uk.co.cascaid.iebe.IebeUser.openUserAnswers.text,openUserAnswer.text.blank.error.openUserAnswers.text,openUserAnswer.text.blank.error.text,openUserAnswer.text.blank.error,uk.co.cascaid.iebe.OpenUserAnswer.text.blank.uk.co.cascaid.iebe.IebeUser.openUserAnswers.text,uk.co.cascaid.iebe.OpenUserAnswer.text.blank.openUserAnswers.text,uk.co.cascaid.iebe.OpenUserAnswer.text.blank.text,uk.co.cascaid.iebe.OpenUserAnswer.text.blank,openUserAnswer.text.blank.uk.co.cascaid.iebe.IebeUser.openUserAnswers.text,openUserAnswer.text.blank.openUserAnswers.text,openUserAnswer.text.blank.text,openUserAnswer.text.blank,blank.uk.co.cascaid.iebe.IebeUser.openUserAnswers.text,blank.openUserAnswers.text,blank.text,blank]; arguments [text,class uk.co.cascaid.iebe.OpenUserAnswer]; default message [Property [{0}] of class [{1}] cannot be blank] Field error in object 'uk.co.cascaid.iebe.IebeUser' on field 'closedUserAnswers.answer': rejected value [null]; codes [uk.co.cascaid.iebe.ClosedUserAnswer.answer.nullable.error.uk.co.cascaid.iebe.IebeUser.closedUserAnswers.answer,uk.co.cascaid.iebe.ClosedUserAnswer.answer.nullable.error.closedUserAnswers.answer,uk.co.cascaid.iebe.ClosedUserAnswer.answer.nullable.error.answer,uk.co.cascaid.iebe.ClosedUserAnswer.answer.nullable.error,closedUserAnswer.answer.nullable.error.uk.co.cascaid.iebe.IebeUser.closedUserAnswers.answer,closedUserAnswer.answer.nullable.error.closedUserAnswers.answer,closedUserAnswer.answer.nullable.error.answer,closedUserAnswer.answer.nullable.error,uk.co.cascaid.iebe.ClosedUserAnswer.answer.nullable.uk.co.cascaid.iebe.IebeUser.closedUserAnswers.answer,uk.co.cascaid.iebe.ClosedUserAnswer.answer.nullable.closedUserAnswers.answer,uk.co.cascaid.iebe.ClosedUserAnswer.answer.nullable.answer,uk.co.cascaid.iebe.ClosedUserAnswer.answer.nullable,closedUserAnswer.answer.nullable.uk.co.cascaid.iebe.IebeUser.closedUserAnswers.answer,closedUserAnswer.answer.nullable.closedUserAnswers.answer,closedUserAnswer.answer.nullable.answer,closedUserAnswer.answer.nullable,nullable.uk.co.cascaid.iebe.IebeUser.closedUserAnswers.answer,nullable.closedUserAnswers.answer,nullable.answer,nullable]; arguments [answer,class uk.co.cascaid.iebe.ClosedUserAnswer]; default message [Property [{0}] of class [{1}] cannot be null]

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• Why do child elements cause 'dropleave' to be called (drag-n-drop file upload)?

  - by tundoopani

  I have a HTML5 drag-n-drop script that allows users to drop files in #droparea. The #droparea div has child elements that are also div elements. <div id="droparea"> <div id="showif_no_dragover">Drag files here!</div> <div id="showif_dragover">Drop the files!</div> </div> The associated javascript/jquery is: var droptarget = "#droparea"; $(droptarget).live('dragenter', dragEnter); $(droptarget).live('dragleave', dragExit); $(droptarget).live('dragover', nothing); $(droptarget).live('drop', dropGo); (Side question: should I use .live(), .on() or .bind() here?) I have created a sample jsFiddle with some additional code here: http://jsfiddle.net/PwFr9/3/ If you look at the console, you will notice that as you drag a file within #droparea, dragenter() and dragleave() are called multiple times, even though the drag is still inside #droparea. If you remove the child elements (#child1 and #child2), the problem is gone because the child elements are gone. How can I keep the child elements and prevent them from messing up the drag events? I have searched Stackoverflow and Google for hours without much help. I found this questions here at Stackoverflow: How to keep child elements from interfering with HTML5 dragover and drop events? I don't know why it works, though. I have tried placing 2 div elements on top of each other (via CSS positioning). The top-most div has the drag events attached whereas the bottom-most div has the child elements. I do not like this approach because it doesn't work with the rest of my page and does not allow mouse-click interaction with the bottom-most div. Any help is appreciated! Thank you in advance. Regards, tundoo

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• How do I send an XML document to an ASP.NET MVC page for manipuation

  - by Decker

  I have some hierarchical data stored as an multiple XML files on the server according to a vendor's schema. In my ASP.NET MVC (2!) application, I'd like the user to choose one of these hierarchies (i.e. file -- I provide a list in my controller's Index action). When the user selects one to "edit" my edit action should return a page that presents the XML hierarchy (it's a representation of a folder tree). So my thoughts are that the view would return HTML that contained a JQuery on load ajax call back to the server for the XML data -- at which point I would present the tree using one of the many JQuery tree controls. On the client side I'd like the user to manipulate the tree and when done, I'd like to post back the new hierarchy where I would replace the original XML file that represents that hierarchy. So my questions are: What form should I use to send the data down? XML or JSON?. If I send down XML then I would have to not only read the XML -- which JQuery can do -- but I would also have to be able to modify that XML and then send it back. Can I use JQuery to modify this XML DOM? And will all the namespace declarations be preserved? What form should I send the data back? If I originally sent the client the hierarchy as JSON (using JsonResult), then presumably I would have a hierarchy of javascript objects. What options would I have to post that back? Would I have to recreate the XML reprentation on the client and post that back? Or should I serialize back to JSON, post that to the server, and then have the server do the work of recreating the XML according to the schema. Thanks for any advice.

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• Jquery - custom countdown

  - by matthewsteiner

  So I found this countdown at http://davidwalsh.name/jquery-countdown-plugin, I altered it a little bit: jQuery.fn.countDown = function(settings,to) { settings = jQuery.extend({ duration: 1000, startNumber: $(this).text(), endNumber: 0, callBack: function() { } }, settings); return this.each(function() { //where do we start? if(!to && to != settings.endNumber) { to = settings.startNumber; } //set the countdown to the starting number $(this).text(to); //loopage $(this).animate({ 'fontSize': settings.endFontSize },settings.duration,'',function() { if(to > settings.endNumber + 1) { $(this).text(to - 1).countDown(settings,to - 1); } else { settings.callBack(this); } }); }); }; Then I have this code: $(document).ready(function(){ $('.countdown').countDown({ callBack: function(me){ $(me).text('THIS IS THE TEXT'); } }); }); I don't mind taking everything out of the "animate" loop; I'd prefer that since nothing needs to be animated. (I don't need the font size to change). So everything's working to a point. I have a span with class countdown and whatever is in it when the page is refreshed goes down second by second. However, I need it to be formatted in M:S format. So, my two questions: 1) What can I use instead of animate to take care of the loop yet maintain the callback 2) How (where in the code should I) can I play with the time format? Thanks.

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• Why is MySQL with InnoDB doing a table scan when key exists and choosing to examine 70 times more ro

  - by andysk

  Hello, I'm troubleshooting a query performance problem. Here's an expected query plan from explain: mysql> explain select * from table1 where tdcol between '2010-04-13:00:00' and '2010-04-14 03:16'; +----+-------------+--------------------+-------+---------------+--------------+---------+------+---------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+--------------------+-------+---------------+--------------+---------+------+---------+-------------+ | 1 | SIMPLE | table1 | range | tdcol | tdcol | 8 | NULL | 5437848 | Using where | +----+-------------+--------------------+-------+---------------+--------------+---------+------+---------+-------------+ 1 row in set (0.00 sec) That makes sense, since the index named tdcol (KEY tdcol (tdcol)) is used, and about 5M rows should be selected from this query. However, if I query for just one more minute of data, we get this query plan: mysql> explain select * from table1 where tdcol between '2010-04-13 00:00' and '2010-04-14 03:17'; +----+-------------+--------------------+------+---------------+------+---------+------+-----------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+--------------------+------+---------------+------+---------+------+-----------+-------------+ | 1 | SIMPLE | table1 | ALL | tdcol | NULL | NULL | NULL | 381601300 | Using where | +----+-------------+--------------------+------+---------------+------+---------+------+-----------+-------------+ 1 row in set (0.00 sec) The optimizer believes that the scan will be better, but it's over 70x more rows to examine, so I have a hard time believing that the table scan is better. Also, the 'USE KEY tdcol' syntax does not change the query plan. Thanks in advance for any help, and I'm more than happy to provide more info/answer questions.

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• Web Servicet Client in JBOSS 5.1 with JDK6

  - by dcp

  This is a continuation of the question here: http://stackoverflow.com/questions/2435286/jboss-does-app-have-to-be-compiled-under-same-jdk-as-jboss-is-running-under It's different enough though that it required a new question. I am trying to use jdk6 to run JBOSS 5.1, and I downloaded the JDK6 version of JBOSS 5.1. This works fine and my EAR application deploys fine. However, when I want to run a web service client with code like this: public static void main(String[] args) throws Exception { System.out.println("creating the web service client..."); TestClient client = new TestClient("http://localhost:8080/tc_test_project-tc_test_project/TestBean?wsdl"); Test service = client.getTestPort(); System.out.println("calling service.retrieveAll() using the service client"); List<TestEntity> list = service.retrieveAll(); System.out.println("the number of elements in list retrieved using the client is " + list.size()); } I get the following exception: javax.xml.ws.WebServiceException: java.lang.UnsupportedOperationException: setProperty must be overridden by all subclasses of SOAPMessage at org.jboss.ws.core.jaxws.client.ClientImpl.handleRemoteException(ClientImpl.java:396) at org.jboss.ws.core.jaxws.client.ClientImpl.invoke(ClientImpl.java:302) at org.jboss.ws.core.jaxws.client.ClientProxy.invoke(ClientProxy.java:170) at org.jboss.ws.core.jaxws.client.ClientProxy.invoke(ClientProxy.java:150) Now, here's the really interesting part. If I change the JDK that my the code above is running under from JDK6 to JDK5, the exception above goes away! It's really strange. The only way I found for the code above to run under JDK6 was to take the JBOSS_HOME/lib/endorsed folder and copy it to JDK6_HOME/lib. This seems like it shouldn't be necessary, but it is. Is there any other way to make this work other than using the workaround I just described?

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• Cluster failover and strange gratuitous arp behavior

  - by lazerpld

  I am experiencing a strange Windows 2008R2 cluster related issue that is bothering me. I feel that I have come close as to what the issue is, but still don't fully understand what is happening. I have a two node exchange 2007 cluster running on two 2008R2 servers. The exchange cluster application works fine when running on the "primary" cluster node. The problem occurs when failing over the cluster ressource to the secondary node. When failing over the cluster to the "secondary" node, which for instance is on the same subnet as the "primary", the failover initially works ok and the cluster ressource continues to work for a couple of minutes on the new node. Which means that the recieving node does send out a gratuitous arp reply packet that updated the arp tables on the network. But after x amount of time (typically within 5 minutes time) something updates the arp-tables again because all of a sudden the cluster service does not answer to pings. So basically I start a ping to the exchange cluster address when its running on the "primary node". It works just great. I failover the cluster ressource group to the "secondary node" and I only have loss of one ping which is acceptable. The cluster ressource still answers for some time after being failed over and all of a sudden the ping starts timing out. This is telling me that the arp table initially is updated by the secondary node, but then something (which I haven't found out yet) wrongfully updates it again, probably with the primary node's MAC. Why does this happen - has anyone experienced the same problem? The cluster is NOT running NLB and the problem stops immidiately after failing over back to the primary node where there are no problems. Each node is using NIC teaming (intel) with ALB. Each node is on the same subnet and has gateway and so on entered correctly as far as I am concerned. Edit: I was wondering if it could be related to network binding order maybe? Because I have noticed that the only difference I can see from node to node is when showing the local arp table. On the "primary" node the arp table is generated on the cluster address as the source. While on the "secondary" its generated from the nodes own network card. Any input on this? Edit: Ok here is the connection layout. Cluster address: A.B.6.208/25 Exchange application address: A.B.6.212/25 Node A: 3 physical nics. Two teamed using intels teaming with the address A.B.6.210/25 called public The last one used for cluster traffic called private with 10.0.0.138/24 Node B: 3 physical nics. Two teamed using intels teaming with the address A.B.6.211/25 called public The last one used for cluster traffic called private with 10.0.0.139/24 Each node sits in a seperate datacenter connected together. End switches being cisco in DC1 and NEXUS 5000/2000 in DC2. Edit: I have been testing a little more. I have now created an empty application on the same cluster, and given it another ip address on the same subnet as the exchange application. After failing this empty application over, I see the exact same problem occuring. After one or two minutes clients on other subnets cannot ping the virtual ip of the application. But while clients on other subnets cannot, another server from another cluster on the same subnet has no trouble pinging. But if i then make another failover to the original state, then the situation is the opposite. So now clients on same subnet cannot, and on other they can. We have another cluster set up the same way and on the same subnet, with the same intel network cards, the same drivers and same teaming settings. Here we are not seeing this. So its somewhat confusing. Edit: OK done some more research. Removed the NIC teaming of the secondary node, since it didnt work anyway. After some standard problems following that, I finally managed to get it up and running again with the old NIC teaming settings on one single physical network card. Now I am not able to reproduce the problem described above. So it is somehow related to the teaming - maybe some kind of bug? Edit: Did some more failing over without being able to make it fail. So removing the NIC team looks like it was a workaround. Now I tried to reestablish the intel NIC teaming with ALB (as it was before) and i still cannot make it fail. This is annoying due to the fact that now i actually cannot pinpoint the root of the problem. Now it just seems to be some kind of MS/intel hick-up - which is hard to accept because what if the problem reoccurs in 14 days? There is a strange thing that happened though. After recreating the NIC team I was not able to rename the team to "PUBLIC" which the old team was called. So something has not been cleaned up in windows - although the server HAS been restarted! Edit: OK after restablishing the ALB teaming the error came back. So I am now going to do some thorough testing and i will get back with my observations. One thing is for sure. It is related to Intel 82575EB NICS, ALB and Gratuitous Arp.

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• ASP Calendar Date Pick

  - by Steven

  I am attempting to construct my own date picker using code from several sources. Specifically, I am now populating the textbox with a calendar click. Two questions: Why does the first click refresh the page without doing anything? How can I have the textbox update without refreshing the entire page? myDate.ascx <%@ Control Language="vb" AutoEventWireup="false" CodeBehind="myDate.ascx.vb" Inherits="Website.myDate" %> <script language="javascript" type="text/javascript"> function toggleCalendar(myID) { var obj = document.getElementById(myID) obj.style.display = (obj.style.display == "none") ? "" : "none"; } </script> <asp:TextBox ID="dateText" runat="server" > </asp:TextBox> <input type="button" name="dateBtn" value="x" onclick="toggleCalendar('<%=dateCal.clientID%>');" /> <asp:Calendar ID="dateCal" runat="server" ></asp:Calendar> myDate.ascx.vb Partial Public Class myDate Inherits System.Web.UI.UserControl Protected Sub dateCal_SelectionChanged _ (ByVal sender As Object, ByVal e As EventArgs) _ Handles dateCal.SelectionChanged dateText.Text = dateCal.SelectedDate 'update text box' dateCal.Style("display") = "none" 'hide calendar' End Sub End Class

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• WCF Service instead of ASMX Web Service?

  - by wchrisjohnson

  I'm writing a SOAP Server that will act as an endpoint for an external client. The external client expects SOAP 1.1. I'll be taking embedded business objects in the SOAP messages and passing them to an internal application, getting responses back and responding with SOAP messages to the eternal client. I did the traditional ASMX based web services several years ago. Now, I've been exploring WCF Services and wondering the best approach to take. 1) Should WCF be considered a superset of ASMX web services? 2) Is there any reason to still write new web services using ASMX instead of WCF? 3) Does WCF provide better facilities for working with SOAP messages, as opposed to SOAP Extensions? 4) Can I restrict communication to SOAP 1.1 using WCF, the way I can with a web.config change in ASMX? 5) Does WCF have an easy way to log or review the requests that hit the service without resorting to something like SOAP extensions? Sorry my questions are not very specific; still trying to get handle on what I need to know... Using VS2008, Windows Server 2008. Chris

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• How does Select statement works in a Dynamic Linq Query?

  - by Richard77

  Hello, 1) I've a Product table with 4 columns: ProductID, Name, Category, and Price. Here's the regular linq to query this table. public ActionResult Index() { private ProductDataContext db = new ProductDataContext(); var products = from p in db.Products where p.Category == "Soccer" select new ProductInfo { Name = p.Name, Price = p.Price} return View(products); } Where ProductInfo is just a class that contains 2 properties (Name and Price). The Index page Inherits ViewPage - IEnumerable - ProductInfo. Everything works fine. 2) To dynamicaly execute the above query, I do this: Public ActionResult Index() { var products = db.Products .Where("Category = \"Soccer\"") .Select(/* WHAT SOULD I WRITE HERE TO SELECT NAME & PRICE?*/) return View(products); } I'm using both 'System.Lind.Dynamic' namespace and the DynamicLibrary.cs (downloaded from ScottGu blog). Here are my questions: What expression do I use to select only Name and Price? (Most importantly) How do I retrieve the data in my view? (i.e. What type the ViewPage inherits? ProductInfo?)

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• PlaySound linker error in C++

  - by logic-unit

  Hello, I'm getting this error: [Linker error] undefined reference to 'PlaySoundA@12' Id returned 1 exit status From this code: // c++ program to generate a random sequence of numbers then play corresponding audio files #include <windows.h> #include <mmsystem.h> #include <iostream> #pragma comment(lib, "winmm.lib") using namespace std; int main() { int i; i = 0; // set the value of i while (i <= 11) // set the loop to run 11 times { int number; number = rand() % 10 + 1; // generate a random number sequence // cycling through the numbers to find the right wav and play it if (number == 0) { PlaySound("0.wav", NULL, SND_FILENAME); // play the random number } else if (number == 1) { PlaySound("1.wav", NULL, SND_FILENAME); // play the random number } //else ifs repeat to 11... i++; // increment i } return 0; } I've tried absolute and relative paths for the wavs, the file size of them is under 1Mb each too. I've read another thread here on the subject: http://stackoverflow.com/questions/1565439/how-to-playsound-in-c As you may well have guessed this is my first C++ program, so my knowledge is limited with where to go next. I've tried pretty much every page Google has on the subject including MSDN usage page. Any ideas? Thanks in advance...

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