Search Results

Search found 20211 results on 809 pages for 'language implementation'.

Page 775/809 | < Previous Page | 771 772 773 774 775 776 777 778 779 780 781 782  | Next Page >

  • jQuery e.stopPropagation() - how to use without breaking dropbox functionality altogether?

    - by Knut Ole
    Short story: stopPropagation() prevents a dropdown menu from closing - which is good. But it also prevents the dropbox from opening next time around - which is bad. Long story: I'm using Twitter-Bootstrap and I've put a search box inside the dropdown menu like so: <div id="search_word_menu" style="position:absolute;right:157px;top:60px;"> <ul class="nav nav-pills"> <li class="dropdown" id="menu200"> <a class="dropdown-toggle btn-inverse" data-toggle="dropdown" style="width:117px;position:relative;left:2px" href="#menu200"> <i class="icon-th-list icon-white"></i> Testing <b class="caret"></b> </a> <ul class="dropdown-menu"> <li><a href="#">Retweets</a></li> <li><a href="#">Favourites</a></li> <li class="divider"></li> <li><a href="#">A list</a></li> <li class="divider"></li> <li><a href="#">A saved search</a></li> <li><a href="#">A saved #hashtag</a></li> <li class="divider"></li> <li> <!-- HERE --> <input id="drop_search" type="text" class="search_box_in_menu" value="Search..."> </li> </ul> </li> </ul> When I click inside the searchbox, the default behaviour is obviously to close the dropdown - but that makes it rather hard to write in a search term. So I've tried with the e.stopPropagation(), which does indeed prevent the dropdown from closing. Then, when I press enter in the searchbox, I'm closing the dropdown with a .toggle() - also seems to work fine. The PROBLEM arises when I want to to it all again, because the e.stopPropagation() has now disabled the dropdown alltogether - ie. when I press the dropdown menu, it doesn't open anymore! This is because of stopPropagation(), no doubt - but how can I resolve this, so that I get the aforementioned functionality, but without breaking the rest altogether? jQuery below: $(document).ready(function() { console.log("document.ready - "); //clearing search box on click $(".search_box_in_menu").click(function(e) { e.stopPropagation(); // works for the specific task console.log(".search_box_in_menu - click."); if($(this).val() == 'Search...') { $(this).val(''); console.log(".search_box_in_menu - value removed."); }; //return false; //this is e.preventDefault() and e.stopPropagation() }); // when pressing enter key in search box $('.search_box_in_menu').keypress(function(e) { var keycode = (e.keyCode ? e.keyCode : e.which); if(keycode == '13') { console.log(".search_box_in_menu - enter-key pressed."); console.log($(this).val()); $(this).closest('.dropdown-menu').toggle(); //works } }); $('.dropdown').click(function() { console.log(".dropdown - click."); $(this).closest('.dropdown-toggle').toggle(); //does nothing }); Would greatly appreciate some help! I'm starting to suspect this might be a bootstrapped-only problem, or at least caused by their implementation - but it's beyond me atm.

    Read the article

  • Algorithm to select groups of similar items in 2d array

    - by mafutrct
    There is a 2d array of items (in my case they are called Intersections). A certain item is given as a start. The task is to find all items directly or indirectly connected to this item that satisfy a certain function. So the basic algorithm is like this: Add the start to the result list. Repeat until no modification: Add each item in the array that satisfies the function and touches any item in the result list to the result list. My current implementation looks like this: private IList<Intersection> SelectGroup ( Intersection start, Func<Intersection, Intersection, bool> select) { List<Intersection> result = new List<Intersection> (); Queue<Intersection> source = new Queue<Intersection> (); source.Enqueue (start); while (source.Any ()) { var s = source.Dequeue (); result.Add (s); foreach (var neighbour in Neighbours (s)) { if (select (start, neighbour) && !result.Contains (neighbour) && !source.Contains (neighbour)) { source.Enqueue (neighbour); } } } Debug.Assert (result.Distinct ().Count () == result.Count ()); Debug.Assert (result.All (x => select (x, result.First ()))); return result; } private List<Intersection> Neighbours (IIntersection intersection) { int x = intersection.X; int y = intersection.Y; List<Intersection> list = new List<Intersection> (); if (x > 1) { list.Add (GetIntersection (x - 1, y)); } if (y > 1) { list.Add (GetIntersection (x, y - 1)); } if (x < Size) { list.Add (GetIntersection (x + 1, y)); } if (y < Size) { list.Add (GetIntersection (x, y + 1)); } return list; } (The select function takes a start item and returns true iff the second item satisfies.) This does its job and turned out to be reasonable fast for the usual array sizes (about 20*20). However, I'm interested in further improvements. Any ideas? Example (X satisfies in relation to other Xs, . does never satisfy): .... XX.. .XX. X... In this case, there are 2 groups: a central group of 4 items and a group of a single item in the lower left. Selecting the group (for instance by starting item [2, 2]) returns the former, while the latter can be selected using the starting item and sole return value [0, 3]. Example 2: .A.. ..BB A.AA This time there are 4 groups. The 3 A groups are not connected, so they are returned as separate groups. The bigger A and B groups are connected, but A does not related to B so they are returned as separate groups.

    Read the article

  • Please recommend me intermediate-to-advanced Python books to buy.

    - by anonnoir
    I'm in the final year, final semester of my law degree, and will be graduating very soon. (April, to be specific.) But before I begin practice, I plan to take 2 two months off, purely for serious programming study. So I'm currently looking for some Python-related books, gauged intermediate to advanced, which are interesting (because of the subject matter itself) and possibly useful to my future line of work. I've identified 2 possible purchases at the moment: Natural Language Processing with Python. The law deals mostly with words, and I've quite a number of ideas as to where I might go with NLP. Data extraction, summaries, client management systems linked with document templates, etc. Programming Collective Intelligence. This book fascinates me, because I've always liked the idea of machine learning (and I'm currently studying it by the side too, for fun). I'd like to build/play around with Web 2.0 applications; and who knows if I can apply some of the things I learn to my legal work. (E.g. Playground experiments to determine how and under what circumstances judges might be biased, by forcing algorithms to pore through judgments and calculate similarities, etc.) Please feel free to criticize my current choices, but do at least offer or recommend other books that I should read in their place. My budget can deal with 4 books, max. These books will be used heavily throughout the 2 months; I will be reading them back to back, absorbing the explanations given, and hacking away at their code. Also, the books themselves should satisfy 2 main criteria: Application. The book must teach how to solve problems. I like reading theory, but I want to build things and solve problems first. Even playful applications are fine, because games and experiments always have real-world applications sooner or later. Readability. I like reading technical books, no matter how difficult they are. I enjoy the effort and the feeling that you're learning something. But the book shouldn't contain code or explanations that are too cryptic or erratic. Even if it's difficult, the book's content should be accessible with focused reading. Note: I realize that I am somewhat of a beginner to the whole programming thing, so please don't put me down. But from experience, I think it's better to aim up and leave my comfort zone when learning new things, rather than to just remain stagnant the way I am. (At least the difficulty gives me focus: i.e. if a programmer can be that good, perhaps if I sustain my own efforts I too can be as good as him someday.) If anything, I'm also a very determined person, so two months of day-to-night intensive programming study with nothing else on my mind should, I think, give me a bit of a fighting chance to push my programming skills to a much higher level.

    Read the article

  • Why doe my UITableView only show two rows of each section?

    - by Mike Owens
    I have a UITableView and when I build it only two rows will be displayed. Each section has more than two cells to be displayed, I am confused since they are all done the same?`#import #import "Store.h" import "VideoViewController.h" @implementation Store @synthesize listData; // Implement viewDidLoad to do additional setup after loading the view, typically from a nib. - (void)viewDidLoad { [self createTableData]; [super viewDidLoad]; } (void)didReceiveMemoryWarning { // Releases the view if it doesn't have a superview. [super didReceiveMemoryWarning]; // Release any cached data, images, etc that aren't in use. } (void)viewDidUnload { //self.listData = nil; //[super viewDidUnload]; // Release any retained subviews of the main view. // e.g. self.myOutlet = nil; } pragma mark - pragma mark Table View Data Source Methods // Customize the number of sections in the table view. - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return [videoSections count]; } //Get number of rows -(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return [self.listData count]; } -(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *StoreTableIdentifier = @"StoreTableIdentifier"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:StoreTableIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:StoreTableIdentifier] autorelease]; } cell.textLabel.text = [[[listData objectAtIndex:indexPath.section] objectAtIndex:indexPath.row] objectForKey:@"name"]; //Change font and color of tableView cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator; cell.textLabel.font=[UIFont fontWithName:@"Georgia" size:16.0]; cell.textLabel.textColor = [UIColor brownColor]; return cell; } -(NSString *)tableView: (UITableView *)tableView titleForHeaderInSection: (NSInteger) section { return [videoSections objectAtIndex:section]; } -(void)tableView: (UITableView *)tableView didSelectRowAtIndexPath: (NSIndexPath *)indexPath { VideoViewController *videoViewController = [[VideoViewController alloc] initWithNibName: @"VideoViewController" bundle:nil]; videoViewController.detailURL = [[NSURL alloc] initWithString: [[[listData objectAtIndex:indexPath.section] objectAtIndex:indexPath.row] objectForKey:@"url"]]; videoViewController.title = [[[listData objectAtIndex:indexPath.section] objectAtIndex:indexPath.row] objectForKey:@"name"]; [self.navigationController pushViewController:videoViewController animated:YES]; [videoViewController release]; } pragma mark Table View Methods //Data in table cell -(void) createTableData { NSMutableArray *beginningVideos; NSMutableArray *intermediateVideos; videoSections = [[NSMutableArray alloc] initWithObjects: @"Beginning Videos", @"Intermediate Videos", nil]; beginningVideos = [[NSMutableArray alloc] init]; intermediateVideos = [[NSMutableArray alloc] init]; [beginningVideos addObject:[[NSMutableDictionary alloc] initWithObjectsAndKeys:@"Shirts", @"name", @"http://www.andalee.com/iPhoneVideos/testMovie.m4v", @"url", nil]]; [beginningVideos addObject:[[NSMutableDictionary alloc] initWithObjectsAndKeys:@"Posters", @"name", @"http://devimages.apple.com/iphone/samples/bipbopall.html", @"url", nil]]; [beginningVideos addObject:[[NSMutableDictionary alloc] initWithObjectsAndKeys:@"Stickers",@"name", @"http://www.andalee.com/iPhoneVideos/mov.MOV",@"url",nil]]; [beginningVideos addObject:[[NSMutableDictionary alloc] initWithObjectsAndKeys:@"Egyptian",@"name", @"http://www.andalee.com/iPhoneVideos/2ndMovie.MOV",@"url",nil]]; [intermediateVideos addObject:[[NSMutableDictionary alloc] initWithObjectsAndKeys:@"Drum Solo", @"name", @"http://www.andalee.com", @"url", nil]]; [intermediateVideos addObject:[[NSMutableDictionary alloc] initWithObjectsAndKeys:@"Veil", @"name", @"http://www.andalee.com", @"url", nil]]; [intermediateVideos addObject:[[NSMutableDictionary alloc] initWithObjectsAndKeys:@"Three Quarter Shimmy",@"name", @"http://www.andalee.com", @"url",nil]]; listData = [[NSMutableArray alloc] initWithObjects:beginningVideos, intermediateVideos, nil]; [beginningVideos release]; [intermediateVideos release]; } (void)dealloc { [listData release]; [videoSections release]; [super dealloc]; } @end `

    Read the article

  • NSMutableArray memory leak when reloading objects

    - by Davin
    I am using Three20/TTThumbsviewcontroller to load photos. I am struggling since quite a some time now to fix memory leak in setting photosource. I am beginner in Object C & iOS memory management. Please have a look at following code and suggest any obvious mistakes or any errors in declaring and releasing variables. -- PhotoViewController.h @interface PhotoViewController : TTThumbsViewController <UIPopoverControllerDelegate,CategoryPickerDelegate,FilterPickerDelegate,UISearchBarDelegate>{ ...... NSMutableArray *_photoList; ...... @property(nonatomic,retain) NSMutableArray *photoList; -- PhotoViewController.m @implementation PhotoViewController .... @synthesize photoList; ..... - (void)LoadPhotoSource:(NSString *)query:(NSString *)title:(NSString* )stoneName{ NSLog(@"log- in loadPhotosource method"); if (photoList == nil) photoList = [[NSMutableArray alloc] init ]; [photoList removeAllObjects]; @try { sqlite3 *db; NSFileManager *fileMgr = [NSFileManager defaultManager]; NSString* documentsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]; NSString *dbPath = [documentsPath stringByAppendingPathComponent: @"DB.s3db"]; BOOL success = [fileMgr fileExistsAtPath:dbPath]; if(!success) { NSLog(@"Cannot locate database file '%@'.", dbPath); } if(!(sqlite3_open([dbPath UTF8String], &db) == SQLITE_OK)) { NSLog(@"An error has occured."); } NSString *_sql = query;//[NSString stringWithFormat:@"SELECT * FROM Products where CategoryId = %i",[categoryId integerValue]]; const char *sql = [_sql UTF8String]; sqlite3_stmt *sqlStatement; if(sqlite3_prepare(db, sql, -1, &sqlStatement, NULL) != SQLITE_OK) { NSLog(@"Problem with prepare statement"); } if ([stoneName length] != 0) { NSString *wildcardSearch = [NSString stringWithFormat:@"%@%%",[stoneName stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]]; sqlite3_bind_text(sqlStatement, 1, [wildcardSearch UTF8String], -1, SQLITE_STATIC); } while (sqlite3_step(sqlStatement)==SQLITE_ROW) { NSString* urlSmallImage = @"Mahallati_NoImage.png"; NSString* urlThumbImage = @"Mahallati_NoImage.png"; NSString *designNo = [NSString stringWithUTF8String:(char *) sqlite3_column_text(sqlStatement,2)]; designNo = [designNo stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]; NSString *desc = [NSString stringWithUTF8String:(char *) sqlite3_column_text(sqlStatement,7)]; desc = [desc stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]; NSString *caption = designNo;//[designNo stringByAppendingString:desc]; caption = [caption stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]; NSString *smallFilePath = [documentsPath stringByAppendingPathComponent: [NSString stringWithFormat:@"Small%@.JPG",designNo] ]; smallFilePath = [smallFilePath stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]; if ([fileMgr fileExistsAtPath:smallFilePath]){ urlSmallImage = [NSString stringWithFormat:@"Small%@.JPG",designNo]; } NSString *thumbFilePath = [documentsPath stringByAppendingPathComponent: [NSString stringWithFormat:@"Thumb%@.JPG",designNo] ]; thumbFilePath = [thumbFilePath stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]; if ([fileMgr fileExistsAtPath:thumbFilePath]){ urlThumbImage = [NSString stringWithFormat:@"Thumb%@.JPG",designNo]; } NSNumber *photoProductId = [NSNumber numberWithInt:(int)sqlite3_column_int(sqlStatement, 0)]; NSNumber *photoPrice = [NSNumber numberWithInt:(int)sqlite3_column_int(sqlStatement, 6)]; char *productNo1 = sqlite3_column_text(sqlStatement, 3); NSString* productNo; if (productNo1 == NULL) productNo = nil; else productNo = [NSString stringWithUTF8String:productNo1]; Photo *jphoto = [[[Photo alloc] initWithCaption:caption urlLarge:[NSString stringWithFormat:@"documents://%@",urlSmallImage] urlSmall:[NSString stringWithFormat:@"documents://%@",urlSmallImage] urlThumb:[NSString stringWithFormat:@"documents://%@",urlThumbImage] size:CGSizeMake(123, 123) productId:photoProductId price:photoPrice description:desc designNo:designNo productNo:productNo ] autorelease]; [photoList addObject:jphoto]; [jphoto release]; } } @catch (NSException *exception) { NSLog(@"An exception occured: %@", [exception reason]); } self.photoSource = [[[MockPhotoSource alloc] initWithType:MockPhotoSourceNormal title:[NSString stringWithFormat: @"%@",title] photos: photoList photos2:nil] autorelease]; } Memory leaks happen when calling above LoadPhotosource method again with different query... I feel its something wrong in declaring NSMutableArray (photoList), but can't figure out how to fix memory leak. Any suggestion is really appreciated.

    Read the article

  • Is it safe to assert a functions return type?

    - by wb
    This question is related to this question. I have several models stored in a collection. I loop through the collection and validate each field. Based on the input, a field can either be successful, have an error or a warning. Is it safe to unit test each decorator and assert that the type of object returned is what you would expect based on the given input? I could perhaps see this being an issue for a language with function return types since my validation function can return one of 3 types. This is the code I'm fiddling with: <!-- #include file = "../lib/Collection.asp" --> <style type="text/css"> td { padding: 4px; } td.error { background: #F00F00; } td.warning { background: #FC0; } </style> <% Class UserModel Private m_Name Private m_Age Private m_Height Public Property Let Name(value) m_Name = value End Property Public Property Get Name() Name = m_Name End Property Public Property Let Age(value) m_Age = value End Property Public Property Get Age() Age = m_Age End Property Public Property Let Height(value) m_Height = value End Property Public Property Get Height() Height = m_Height End Property End Class Class NameValidation Private m_Name Public Function Init(name) m_Name = name End Function Public Function Validate() Dim validationObject If Len(m_Name) < 5 Then Set validationObject = New ValidationError Else Set validationObject = New ValidationSuccess End If validationObject.CellValue = m_Name Set Validate = validationObject End Function End Class Class AgeValidation Private m_Age Public Function Init(age) m_Age = age End Function Public Function Validate() Dim validationObject If m_Age < 18 Then Set validationObject = New ValidationError ElseIf m_Age = 18 Then Set validationObject = New ValidationWarning Else Set validationObject = New ValidationSuccess End If validationObject.CellValue = m_Age Set Validate = validationObject End Function End Class Class HeightValidation Private m_Height Public Function Init(height) m_Height = height End Function Public Function Validate() Dim validationObject If m_Height > 400 Then Set validationObject = New ValidationError ElseIf m_Height = 324 Then Set validationObject = New ValidationWarning Else Set validationObject = New ValidationSuccess End If validationObject.CellValue = m_Height Set Validate = validationObject End Function End Class Class ValidationError Private m_CSSClass Private m_CellValue Public Property Get CSSClass() CSSClass = "error" End Property Public Property Let CellValue(value) m_CellValue = value End Property Public Property Get CellValue() CellValue = m_CellValue End Property End Class Class ValidationWarning Private m_CSSClass Private m_CellValue Public Property Get CSSClass() CSSClass = "warning" End Property Public Property Let CellValue(value) m_CellValue = value End Property Public Property Get CellValue() CellValue = m_CellValue End Property End Class Class ValidationSuccess Private m_CSSClass Private m_CellValue Public Property Get CSSClass() CSSClass = "" End Property Public Property Let CellValue(value) m_CellValue = value End Property Public Property Get CellValue() CellValue = m_CellValue End Property End Class Class ModelValidator Public Function ValidateModel(model) Dim modelValidation : Set modelValidation = New CollectionClass ' Validate name Dim name : Set name = New NameValidation name.Init model.Name modelValidation.Add name ' Validate age Dim age : Set age = New AgeValidation age.Init model.Age modelValidation.Add age ' Validate height Dim height : Set height = New HeightValidation height.Init model.Height modelValidation.Add height Dim validatedProperties : Set validatedProperties = New CollectionClass Dim modelVal For Each modelVal In modelValidation.Items() validatedProperties.Add modelVal.Validate() Next Set ValidateModel = validatedProperties End Function End Class Dim modelCollection : Set modelCollection = New CollectionClass Dim user1 : Set user1 = New UserModel user1.Name = "Mike" user1.Age = 12 user1.Height = 32 modelCollection.Add user1 Dim user2 : Set user2 = New UserModel user2.Name = "Phil" user2.Age = 18 user2.Height = 432 modelCollection.Add user2 Dim user3 : Set user3 = New UserModel user3.Name = "Michele" user3.Age = 32 user3.Height = 324 modelCollection.Add user3 ' Validate all models in the collection Dim modelValue Dim validatedModels : Set validatedModels = New CollectionClass For Each modelValue In modelCollection.Items() Dim objModelValidator : Set objModelValidator = New ModelValidator validatedModels.Add objModelValidator.ValidateModel(modelValue) Next %> <table> <tr> <td>Name</td> <td>Age</td> <td>Height</td> </tr> <% Dim r, c For Each r In validatedModels.Items() %><tr><% For Each c In r.Items() %><td class="<%= c.CSSClass %>"><%= c.CellValue %></td><% Next %></tr><% Next %> </table> Thank you.

    Read the article

  • Qthread - trouble shutting down threads

    - by Bryan Greenway
    For the last few days, I've been trying out the new preferred approach for using QThreads without subclassing QThread. The trouble I'm having is when I try to shutdown a set of threads that I created. I regularly get a "Destroyed while thread is still running" message (if I'm running in Debug mode, I also get a Segmentation Fault dialog). My code is very simple, and I've tried to follow the examples that I've been able to find on the internet. My basic setup is as follows: I've a simple class that I want to run in a separate thread; in fact, I want to run 5 instances of this class, each in a separate thread. I have a simple dialog with a button to start each thread, and a button to stop each thread (10 buttons). When I click one of the "start" buttons, a new instance of the test class is created, a new QThread is created, a movetothread is called to get the test class object to the thread...also, since I have a couple of other members in the test class that need to move to the thread, I call movetothread a few additional times with these other items. Note that one of these items is a QUdpSocket, and although this may not make sense, I wanted to make sure that sockets could be moved to a separate thread in this fashion...I haven't tested the use of the socket in the thread at this point. Starting of the threads all seem to work fine. When I use the linux top command to see if the threads are created and running, they show up as expected. The problem occurs when I begin stopping the threads. I randomly (or it appears to be random) get the error described above. Class that is to run in separate thread: // Declaration class TestClass : public QObject { Q_OBJECT public: explicit TestClass(QObject *parent = 0); QTimer m_workTimer; QUdpSocket m_socket; Q_SIGNALS: void finished(); public Q_SLOTS: void start(); void stop(); void doWork(); }; // Implementation TestClass::TestClass(QObject *parent) : QObject(parent) { } void TestClass::start() { connect(&m_workTimer, SIGNAL(timeout()),this,SLOT(doWork())); m_workTimer.start(50); } void TestClass::stop() { m_workTimer.stop(); emit finished(); } void TestClass::doWork() { int j; for(int i = 0; i<10000; i++) { j = i; } } Inside my main app, code called to start the first thread (similar code exists for each of the other threads): mp_thread1 = new QThread(); mp_testClass1 = new TestClass(); mp_testClass1->moveToThread(mp_thread1); mp_testClass1->m_socket.moveToThread(mp_thread1); mp_testClass1->m_workTimer.moveToThread(mp_thread1); connect(mp_thread1, SIGNAL(started()), mp_testClass1, SLOT(start())); connect(mp_testClass1, SIGNAL(finished()), mp_thread1, SLOT(quit())); connect(mp_testClass1, SIGNAL(finished()), mp_testClass1, SLOT(deleteLater())); connect(mp_testClass1, SIGNAL(finished()), mp_thread1, SLOT(deleteLater())); connect(this,SIGNAL(stop1()),mp_testClass1,SLOT(stop())); mp_thread1->start(); Also inside my main app, this code is called when a stop button is clicked for a specific thread (in this case thread 1): emit stop1(); Sometimes it appears that threads are stopped and destroyed without issue. Other times, I get the error described above. Any guidance would be greatly appreciated. Thanks, Bryan

    Read the article

  • Where are the function address literals in c++?

    - by academicRobot
    First of all, maybe literals is not the right term for this concept, but its the closest I could think of (not literals in the sense of functions as first class citizens). <UPDATE> After some reading with help from answer by Chris Dodd, what I'm looking for is literal function addresses as template parameters. Chris' answer indicates how to do this for standard functions, but how can the addresses of member functions be used as template parameters? Since the standard prohibits non-static member function addresses as template parameters (c++03 14.3.2.3), I suspect the work around is quite complicated. Any ideas for a workaround? Below the original form of the question is left as is for context. </UPDATE> The idea is that when you make a conventional function call, it compiles to something like this: callq <immediate address> But if you make a function call using a function pointer, it compiles to something like this: mov <memory location>,%rax callq *%rax Which is all well and good. However, what if I'm writing a template library that requires a callback of some sort with a specified argument list and the user of the library is expected to know what function they want to call at compile time? Then I would like to write my template to accept a function literal as a template parameter. So, similar to template <int int_literal> struct my_template {...};` I'd like to write template <func_literal_t func_literal> struct my_template {...}; and have calls to func_literal within my_template compile to callq <immediate address>. Is there a facility in C++ for this, or a work around to achieve the same effect? If not, why not (e.g. some cataclysmic side effects)? How about C++0x or another language? Solutions that are not portable are fine. Solutions that include the use of member function pointers would be ideal. I'm not particularly interested in being told "You are a <socially unacceptable term for a person of low IQ>, just use function pointers/functors." This is a curiosity based question, and it seems that it might be useful in some (albeit limited) applications. It seems like this should be possible since function names are just placeholders for a (relative) memory address, so why not allow more liberal use (e.g. aliasing) of this placeholder. p.s. I use function pointers and functions objects all the the time and they are great. But this post got me thinking about the don't pay for what you don't use principle in relation to function calls, and it seems like forcing the use of function pointers or similar facility when the function is known at compile time is a violation of this principle, though a small one. Edit The intent of this question is not to implement delegates, rather to identify a pattern that will embed a conventional function call, (in immediate mode) directly into third party code, possibly a template.

    Read the article

  • Setting hidden input value in Javascript, then accessing it in c# codebehind

    - by Siegesmith
    Thank you for reading my question. I have been trying to set the value of a hidden input by using Javascript and then access the value from within my C# codebehind. When I run the code that is copied below, the value that is assigned to assignedIDs is "", which I assume is the default value for a hidden input. If I manually set the value in the html tag, then assignedIDs is set to that value. This behavior suggests to me that the value of the input is being reset (re-rendered?) between the onClientClick and onClick events firing. I would appreciate any help with the matter. I have spent hours trying to solve what seems like a very simple problem. html/javascript: <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title>Admin Page - Manage Tasks</title> <script language="javascript" type="text/javascript"> function PopulateAssignedIDHiddenInput() { var source = document.getElementById('assignedLinguistListBox'); var s = ""; var count = source.length; for (var i = count - 1; i >= 0; i--) { var item = source.options[i]; if (s == "") { s = source.options[i].value; } else { s = s.concat(",",source.options[i].value); } } document.getElementById('assignedIDHiddenInput').Value = s; // I have confirmed that, at this point, the value of // the hidden input is set properly } </script> </head> <body> <form id="form1" runat="server"> <div> <asp:Panel id="EditMode" runat="server"> <table style="border: none;"> <tr> <td> <asp:Label ID="availableLinguistLabel" runat="server" Text="Available"></asp:Label><br /> <asp:ListBox ID="availableLinguistListBox" runat="server" Rows="10" SelectionMode="Multiple"></asp:ListBox> </td> <td> <input type="button" name="right" value="&gt;&gt;" onclick="Javascript:MoveItem('availableLinguistListBox', 'assignedLinguistListBox');" /><br /><br /> <input type="button" name="left" value="&lt;&lt;" onclick="Javascript:MoveItem('assignedLinguistListBox', 'availableLinguistListBox');" /> </td> <td> <asp:Label ID="assignedLinguistLabel" runat="server" Text="Assigned To"></asp:Label><br /> <asp:ListBox ID="assignedLinguistListBox" runat="server" Rows="10" SelectionMode="Multiple"></asp:ListBox> </td> </tr> </table> //-snip- <asp:Button ID="save_task_changes_button" runat="server" ToolTip="Click to save changes to task" Text="Save Changes" OnClick="save_task_changes_button_click" OnClientClick="Javascript:PopulateAssignedIDHiddenInput()" /> </asp:Panel> <!-- Hidden Inputs --> <!-- Note that I have also tried setting runat="server" with no change --> <input id="assignedIDHiddenInput" name="assignedIDHiddenInput" type="hidden" /> </div> </form> </body> c# protected void save_task_changes_button_click(object sender, EventArgs e) { string assignedIDs = Request.Form["assignedIDHiddenInput"]; // Here, assignedIDs == ""; also, Request.Params["assignedIDHiddenInput"] == "" // -snip- }

    Read the article

  • Thread locking issue with FileHelpers between calling engine.ReadNext() method and readign engine.Li

    - by Rad
    I use producer/consumer pattern with FileHelpers library to import data from one file (which can be huge) using multiple threads. Each thread is supposed to import a chunk of that file and I would like to use LineNumber property of the FileHelperAsyncEngine instance that is reading the file as primary key for imported rows. FileHelperAsyncEngine internally has an IEnumerator IEnumerable.GetEnumerator(); which is iterated over using engine.ReadNext() method. That internally sets LineNumber property (which seems is not thread safe). Consumers will have Producers assiciated with them that will supply DataTables to Consumers which will consume them via SqlBulkLoad class which will use IDataReader implementation which will iterate over a collection of DataTables which are internal to a Consumer instance. Each instance of will have one SqlBulkCopy instance associate with it. I have thread locking issue. Below is how I create multiple Producer threads. I start each thread afterwords. Produce method on a producer instance will be called determining which chunk of input file will be processed. It seems that engine.LineNumber is not thread safe and I doesn't import a proper LineNumber in the database. It seems that by the time engine.LineNumber is read some other thread called engine.ReadNext() and changed engine.LineNumber property. I don't want to lock the loop that is supposed to process a chunk of input file because I loose parallelism. How to reorganize the code to solve this threading issue? Thanks Rad for (int i = 0; i < numberOfProducerThreads; i++) DataConsumer consumer = dataConsumers[i]; //create a new producer DataProducer producer = new DataProducer(); //consumer has already being created consumer.Subscribe(producer); FileHelperAsyncEngine orderDetailEngine = new FileHelperAsyncEngine(recordType); orderDetailEngine.Options.RecordCondition.Condition = RecordCondition.ExcludeIfBegins; orderDetailEngine.Options.RecordCondition.Selector = STR_ORDR; int skipLines = i * numberOfBufferTablesToProcess * DataBuffer.MaxBufferRowCount; Thread newThread = new Thread(() => { producer.Produce(consumer, inputFilePath, lineNumberFieldName, dict, orderDetailEngine, skipLines, numberOfBufferTablesToProcess); consumer.SetEndOfData(producer); }); producerThreads.Add(newThread); thread.Start();} public void Produce(DataConsumer consumer, string inputFilePath, string lineNumberFieldName, Dictionary<string, object> dict, FileHelperAsyncEngine engine, int skipLines, int numberOfBufferTablesToProcess) { lock (this) { engine.Options.IgnoreFirstLines = skipLines; engine.BeginReadFile(inputFilePath); } int rowCount = 1; DataTable buffer = consumer.BufferDataTable; while (engine.ReadNext() != null) { lock (this) { dict[lineNumberFieldName] = engine.LineNumber; buffer.Rows.Add(ObjectFieldsDataRowMapper.MapObjectFieldsToDataRow(engine.LastRecord, dict, buffer)); if (rowCount % DataBuffer.MaxBufferRowCount == 0) { consumer.AddBufferDataTable(buffer); buffer = consumer.BufferDataTable; } if (rowCount % (numberOfBufferTablesToProcess * DataBuffer.MaxBufferRowCount) == 0) { break; } rowCount++; } } if (buffer.Rows.Count > 0) { consumer.AddBufferDataTable(buffer); } engine.Close(); }

    Read the article

  • extensible database design: automatic ALTER TABLE or serialize() field BLOB ?

    - by mario
    I want an adaptable database scheme. But still use a simple table data gateway in my application, where I just pass an $data[] array for storing. The basic columns are settled in the initial table scheme. There will however arise a couple of meta fields later (ca 10-20). I want some flexibility there and not adapt the database manually each time, or -worse- change the application logic just because of new fields. So now there are two options which seem workable yet not overkill. But I'm not sure about the scalability or database drawbacks. (1) Automatic ALTER TABLE. Whenever the $data array is to be saved, the keys are compared against the current database columns. New columns get defined before the $data is INSERTed into the table. Actually seems simple enough in test code: function save($data, $table="forum") { // columns if ($new_fields = array_diff(array_keys($data), known_fields($table))) { extend_schema($table, $new_fields, $data); } // save $columns = implode("`, `", array_keys($data)); $qm = str_repeat(",?", count(array_keys($data)) - 1); echo ("INSERT INTO `$table` (`$columns`) VALUES (?$qm);"); function known_fields($table) { return unserialize(@file_get_contents("db:$table")) ?: array("id"); function extend_schema($table, $new_fields, $data) { foreach ($new_fields as $field) { echo("ALTER TABLE `$table` ADD COLUMN `$field` VARCHAR;"); Since it is mostly meta information fields, adding them just as VARCHAR seems sufficient. Nobody will query by them anyway. So the database is really just used as storage here. However, while I might want to add a lot of new $data fields on the go, they will not always be populated. (2) serialize() fields into BLOB. Any new/extraneous meta fields could be opaque to the database. Simply sorting out the virtual fields from the real database columns is simple. And the meta fields can just be serialize()d into a blob/text field then: function ext_save($data, $table="forum") { $db_fields = array("id", "content", "flags", "ext"); // disjoin foreach (array_diff(array_keys($data),$db_fields) as $key) { $data["ext"][$key] = $data[$key]; unset($data[$key]); } $data["ext"] = serialize($data["ext"]); Unserializing and unpacking this 'ext' column on read queries is a minor overhead. The advantage is that there won't be any sparsely filled columns in the database, so I guess it's compacter and faster than the AUTO ALTER TABLE approach. Of course, this method prevents ever using one of the new fields in a WHERE or GROUP BY clause. But I think none of the possible meta fields (user_agent, author_ip, author_img, votes, hits, last_modified, ..) would/should ever be used there anyway. So I currently prefer the 'ext' blob approach, even if it's a one-way ticket. How are such columns called usually? (looking for examples/doc) Would you use XML serialization for (very theoretical) in-database queries? The adapting table scheme seems a "cleaner" interface, even if most columns might remain empty then. How does that impact speed? How many such sparse VARCHAR fields can MySQL/innodb stomach? But most importantly: Is there any standard implementation for this? A pseudo ORM with automatic ALTER TABLE tricks? Storing a simple column list seems workable, but something like pdo::getColumnMeta would be more robust.

    Read the article

  • Severe Tomcat crash has me stumped

    - by Eric Banderhide
    I'm pretty used to crashing my tomcat server. But I don't think I made any changes at all and seem to have broken it completely. Was working one min then not the next. I really hope someone can help here is the Catalina.out: Dec 20, 2012 1:35:56 AM org.apache.catalina.startup.Embedded initDirs SEVERE: Cannot find specified temporary folder at Dec 20, 2012 1:35:57 AM org.apache.catalina.core.AprLifecycleListener init INFO: Loaded APR based Apache Tomcat Native library 1.1.23. Dec 20, 2012 1:35:57 AM org.apache.catalina.core.AprLifecycleListener init INFO: APR capabilities: IPv6 [true], sendfile [true], accept filters [false], random [true]. Dec 20, 2012 1:35:57 AM org.apache.coyote.http11.Http11AprProtocol init INFO: Initializing Coyote HTTP/1.1 on http-8040 Dec 20, 2012 1:35:57 AM org.apache.coyote.ajp.AjpAprProtocol init INFO: Initializing Coyote AJP/1.3 on ajp-8042 Dec 20, 2012 1:35:57 AM org.apache.catalina.startup.Catalina load INFO: Initialization processed in 587 ms Dec 20, 2012 1:35:57 AM org.apache.catalina.core.StandardService start INFO: Starting service Catalina Dec 20, 2012 1:35:57 AM org.apache.catalina.core.StandardEngine start INFO: Starting Servlet Engine: Apache Tomcat/6.0.33 Dec 20, 2012 1:35:57 AM org.apache.catalina.startup.HostConfig deployDirectory INFO: Deploying web application directory docs Dec 20, 2012 1:35:57 AM org.apache.catalina.startup.HostConfig deployDirectory INFO: Deploying web application directory ROOT Dec 20, 2012 1:35:57 AM org.apache.catalina.startup.HostConfig deployDirectory INFO: Deploying web application directory myApp Dec 20, 2012 1:35:57 AM org.apache.catalina.loader.WebappClassLoader validateJarFile INFO: validateJarFile(/lhome/me/tomcat6/webapps/myApp/WEB-INF/lib/javax.servlet.jar) - jar not loaded. See Servlet Spec 2.3, section 9.7.2. Offending class: javax/servlet/Servlet.class Dec 20, 2012 1:35:58 AM org.apache.coyote.http11.Http11AprProtocol start INFO: Starting Coyote HTTP/1.1 on http-8040 Dec 20, 2012 1:35:58 AM org.apache.coyote.ajp.AjpAprProtocol start INFO: Starting Coyote AJP/1.3 on ajp-8042 Dec 20, 2012 1:35:58 AM org.apache.catalina.startup.Catalina start INFO: Server startup in 880 ms Error Reading TLE line 1: java.lang.Exception: TLE line 1 not valid first line Error Creating SGP4 Satellite Dec 20, 2012 1:36:26 AM org.apache.coyote.http11.Http11AprProtocol pause INFO: Pausing Coyote HTTP/1.1 on http-8040 Dec 20, 2012 1:36:26 AM org.apache.coyote.ajp.AjpAprProtocol pause INFO: Pausing Coyote AJP/1.3 on ajp-8042 Dec 20, 2012 1:36:27 AM org.apache.catalina.core.StandardService stop INFO: Stopping service Catalina Dec 20, 2012 1:36:30 AM org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc SEVERE: The web application [/myApp] registered the JDBC driver [com.mysql.jdbc.Driver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered. Dec 20, 2012 1:36:30 AM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads SEVERE: The web application [/myApp] is still processing a request that has yet to finish. This is very likely to create a memory leak. You can control the time allowed for requests to finish by using the unloadDelay attribute of the standard Context implementation. Dec 20, 2012 1:36:30 AM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads SEVERE: The web application [/myApp] appears to have started a thread named [Timer-0] but has failed to stop it. This is very likely to create a memory leak. Dec 20, 2012 1:36:30 AM org.apache.coyote.http11.Http11AprProtocol destroy INFO: Stopping Coyote HTTP/1.1 on http-8040 Dec 20, 2012 1:36:30 AM org.apache.coyote.ajp.AjpAprProtocol destroy INFO: Stopping Coyote AJP/1.3 on ajp-8042 Dec 20, 2012 1:37:12 AM org.apache.catalina.startup.Catalina stopServer SEVERE: Catalina.stop: java.net.ConnectException: Connection refused at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339) at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200) at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:391) at java.net.Socket.connect(Socket.java:579) at java.net.Socket.connect(Socket.java:528) at java.net.Socket.<init>(Socket.java:425) at java.net.Socket.<init>(Socket.java:208) at org.apache.catalina.startup.Catalina.stopServer(Catalina.java:422) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:601) at org.apache.catalina.startup.Bootstrap.stopServer(Bootstrap.java:338) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:416) And I have a new log that has been created, I've never seen it before but it seems to think its something severe. A long one but here it is: Massive Error Log I've never seen before

    Read the article

  • New cast exception with VS2010/.Net 4

    - by Trevor
    [ Updated 25 May 2010 ] I've recently upgraded from VS2008 to VS2010, and at the same time upgraded to .Net 4. I've recompiled an existing solution of mine and I'm encountering a Cast exception I did not have before. The structure of the code is simple (although the actual implementation somewhat more complicated). Basically I have: public class SomeClass : ISomeClass { // Stuff } public static class ClassFactory { public static IInterface GetClassInstance<IInterface>(Type classType) { return (IInterface)Activator.CreateInstance(classType); // This throws a cast exception } } // Call the factory with: ISomeClass anInstance = ClassFactory.GetClassInstance<ISomeClass>(typeof(SomeClass)); Ignore the 'sensibleness' of the above - its provides just a representation of the issue rather than the specifics of what I'm doing (e.g. constructor parameters have been removed). The marked line throws the exception: Unable to cast object of type 'Namespace.SomeClass' to type 'Namespace.ISomeClass'. I suspect it may have something to do with the additional DotNet security (and in particular, explicit loading of assemblies, as this is something my app does). The reason I suspect this is that I have had to add to the config file the setting: <runtime> <loadFromRemoteSources enabled="true" /> </runtime> .. but I'm unsure if this is related. Update I see (from comments) that my basic code does not reproduce the issue by itself. Not surprising I suppose. It's going to be tricky to identify which part of a largish 3-tier CQS system is relevant to this problem. One issue might be that there are multiple assemblies involved. My static class is actually a factory provider, and the 'SomeClass' is a class factory (relevant in that the factories are 'registered' within the app via explicit assembly/type loading - see below) . Upfront I use reflection to 'register' all factories (i.e. classes that implement a particular interface) and that I do this when the app starts by identifying the relevant assemblies, loading them and adding them to a cache using (in essence): Loop over (file in files) { Assembly assembly = Assembly.LoadFile(file); baseAssemblyList.Add(assembly); } Then I cache the available types in these assemblies with: foreach (Assembly assembly in _loadedAssemblyList) { Type[] assemblyTypes = assembly.GetTypes(); _loadedTypesCache.AddRange(assemblyTypes); } And then I use this cache to do a variety of reflection operations, including 'registering' of factories, which involves looping through all loaded (cached) types and finding those that implement the (base) Factory interface. I've experienced what may be a similar problem in the past (.Net 3.5, so not exactly the same) with an architecture that involved dynamically creating classes on the server and streaming the compiled binary of those classes to the client app. The problem came when trying to deserialize an instance of the dynamic class on the client from a remote call: the exception said the class type was not know, even though the source and destination types were exactly the same name (including namespace). Basically the cross boundry versions of the class were not recognised as being the same. I solved that by intercepting the deserialization process and explicitly defining the deseriazation class type in the context of the local assemblies. This experience is what makes me think the types are considered mismatched because (somehow) the interface of the actual SomeClass object, and the interface of passed into the Generic method are not considered the same type. So (possibly) my question for those more knowledgable about C#/DotNet is: How does the class loading work that somehow my app thinks there are two versions/types of the interface type and how can I fit that? [ whew ... anyone who got here is quite patient .. thanks ]

    Read the article

  • What does a WinForm application need to be designed for usability, and be robust, clean, and profess

    - by msorens
    One of the principal problems impeding productivity in software implementation is the classic conundrum of “reinventing the wheel”. Of late I am a .NET developer and even the wonderful wizardry of .NET and Visual Studio covers only a portion of this challenging issue. Below I present my initial thoughts both on what is available and what should be available from .NET on a WinForm, focusing on good usability. That is, aspects of an application exposed to the user and making the user experience easier and/or better. (I do include a couple items not visible to the user because I feel strongly about them, such as diagnostics.) I invite you to contribute to these lists. LIST A: Components provided by .NET These are substantially complete components provided by .NET, i.e. those requiring at most trivial coding to use. “About” dialog -- add it with a couple clicks then customize. Persist settings across invocations -- .NET has the support; just use a few lines of code to glue them together. Migrate settings with a new version -- a powerful one, available with one line of code. Tooltips (and infotips) -- .NET includes just plain text tooltips; third-party libraries provide richer ones. Diagnostic support -- TraceSources, TraceListeners, and more are built-in. Internationalization -- support for tailoring your app to languages other than your own. LIST B: Components not provided by .NET These are not supplied at all by .NET or supplied only as rudimentary elements requiring substantial work to be realized. Splash screen -- a small window present during program startup with your logo, loading messages, etc. Tip of the day -- a mini-tutorial presented one bit at a time each time the user starts your app. Check for available updates -- facility to query a server to see if the user is running the latest version of your app, then provide a simple way to upgrade if a new version is found. Maximize to multiple monitors -- the canonical window allows you to maximize to a single monitor only; in my apps I allow maximizing across multiple monitors with a click. Taskbar notifier -- flash the taskbar when your backgrounded app has new info for the user. Options dialogs -- multi-page dialogs letting the user customize the app settings to his/her own preferences. Progress indicator -- for long running operations give the user feedback on how far there is left to go. Memory gauge -- an indicator (either absolute or percentage) of how much memory is used by your app. LIST C: Stylistic and/or tiny bits of functionality This list includes bits of functionality that are too tiny to merit being called a component, along with stylistic concerns (that admittedly do overlap with the Windows User Experience Interaction Guidelines). Design a form for resizing -- unless you are restricting your form to be a fixed size, use anchors and docking so that it does what is reasonable when enlarged or shrunk by the user. Set tab order on a form -- repeated tab presses by the user should advance from field to field in a logical order rather than the default order in which you added fields. Adjust controls to be aware of operating modes -- When starting a background operation with, for example, a “Go” button, disable that “Go” button until the operation completes. Provide access keys for all menu items (per UXGuide). Provide shortcut keys for commonly used menu items (per UXGuide). Set up some (global or important or common) shortcut keys without associating to menu items. Allow some menu items to be invoked with or without modifier keys (shift, control, alt) where the modifier key is useful to vary the operation slightly. Hook up Escape and Enter on child forms to do what is reasonable. Decorate any library classes with documentation-comments and attributes -- this allows Visual Studio to leverage them for Intellisense and property descriptions. Spell check your code! What else would you include?

    Read the article

  • How do I learn algorithms?

    - by Panthe
    Brief History: Just graduated high school, learned a bit of python and C++, have no friends with any helpful computer knowledge at all. Out of anyone i met in my school years I was probably the biggest nerd, but no one really knew. I consider my self to have a vast amount of knowledge on computers and tech then the average person. built/fixed tons of computers, and ability to troubleshoot pretty much any problem I came across. Now that high school is over, Ive really been thinking about my career. Loving, living computers for the past 15 years of my life I decided to take my ability's and try to learn computer programming, why I didn't start earlier I don't know, seems to be big mistake on my part... Doing some research I concluded that Python was the first programming language I should learn, since it was high level and easier to understand then C++ and Java. I also knew that to become good at what I did I needed to know more then just 2 or 3 languages, which didn't seem like a big problem considering once I learned the way Python worked, mainly syntax changed, and the rest would come naturally. I watched a couple of youtube videos, downloaded some book pdf's and snooped around from some tutorials here and there to get the hang of what to do. A two solid weeks had passed of trying to understand the syntax, create small programs that used the basic functions and understanding how it worked, I think i have got the hang of it. It breaks down into what ive been dealing with all this time (although i kinda knew) is that, input,output, loops, functions and other things derived from 0's and 1's storing data and recalling it, ect. (A VERY BASIC IDEA). Ive been able to create small programs, Hangman, file storing, temperature conversion, Caeser Cipher decode/encoding, Fibonacci Sequence and more, which i can create and understand how each work. Being 2 weeks into this, I have learned alot. Nothing at all compared to what i should be lear ning in the years to come if i get a grip on what I'm doing. While doing these programs I wont stop untill I've done doing a practice problem on a book, which embarresing enough will take me a couple hour depending on the complexity of it. I absolutly will not put aside the challenge until its complete, WHICH CAN BE EXTREMELY DRAINING, ive tried most problems without cheating and reached success, which makes me feel extremely proud of my self after completing something after much trial and error. After all this I have met the demon, alogrithm's which seem to be key to effiecent code. I cant seem to rap my head around some of the computer codes people put out there using numbers, and sometimes even basic functions, I have been able to understand them after a while but i know there are alot more complex things to come, considering my self smart, functions that require complex codes, actually hurt my brain. NOTHING EVER IN LIFE HURT MY BRAIN....... not even math classes in highschool, trying to understand some of the stuff people put out there makes me feel like i have a mental disadvantage lol... i still walk forward though, crossing my fingers that the understanding will come with time. Sorry if is this is long i just wish someone takes all these things into consideration when answering my question. even through all these downsides im still pushing through and continuing to try and get good at this, i know reading these tutorials wont make me any good unless i can become creative and make my own, understand other peoples programs, so this leads me to the simple question i could have asked in the beginning..... WHERE IN THE WORLD DO I START ? Ive been trying to find out how to understand some of the open source projects, how i can work with experianced coders to learn from them and help them, but i dont think thats even possible by the way how far people's knowledge is compared to me, i have no freinds who i can learn from, can someone help me and guide me into the right direction.. i have a huge motivation to get good at coding, anything information would be extremely helpful

    Read the article

  • how to pass a string value from one controller to another

    - by shreedevi
    I have a login controller ,and after the successful login i want to pass some string value to the menu page.however it does not work.the application crashes. I have tried possible suggesstion of Ihuk and SAM from the link below http://stackoverflow.com/questions/1685964/how-to-pass-a-string-value-from-one-view-controller-to-another-view-controller loginController.h: #import <UIKit/UIKit.h> @class RootViewController; @class Menu; @interface LoginController : UIViewController { UIButton *login_Button; UITextField *username_TextField; UITextField *password_TextField; RootViewController *mc1; UINavigationController *navigationController; Menu *mv1; } @property(nonatomic,retain) IBOutlet UIButton *login_Button; @property(nonatomic,retain) IBOutlet UITextField *username_TextField; @property(nonatomic,retain) IBOutlet UITextField *password_TextField; @property(nonatomic,retain) RootViewController *mc1; @property (nonatomic, retain) IBOutlet UINavigationController *navigationController; @property(nonatomic,retain)Menu *mv1; - (IBAction)Login_Method:(id)sender; -(id)initWithUserName:(NSString *)name ; @end loginController.m #import "LoginController.h" #import "Menu.h" #import "ViewController.h" #import "RootViewController.h" @implementation LoginController @synthesize mc1,mv1; @synthesize login_Button,username_TextField,password_TextField; @synthesize navigationController; // Implement viewDidLoad to do additional setup after // loading the view, typically from a nib. - (void)viewDidLoad { if (![self.navigationController isNavigationBarHidden]) [self.navigationController setNavigationBarHidden:YES animated:NO]; //[self presentModalViewController:navigationController animated:YES]; } - (void)didReceiveMemoryWarning { // Releases the view if it doesn't have a superview. [super didReceiveMemoryWarning]; // Release any cached data, images, etc that aren't in use. } - (void)viewDidUnload { // Release any retained subviews of the main view. // e.g. self.myOutlet = nil; } - (IBAction)Login_Method:(id)sender { Menu *mv2 = [[Menu alloc] initWithUserName:@"Menu" bundle:nil]; //mv2.l1.text=@"aa"; //i tried this, but not work,so created initWithUserName self.mv1=mv2; [self presentModalViewController:mv1 animated:YES]; // [RootViewController release]; } -(id)initWithUserName:(NSString *)name { self = [super init]; if (nil == self) { return nil; } // display or store login info somewhere [mv1.l1 setText:name]; return self; } -(BOOL)textFieldShouldReturn:(UITextField *)theTextField { [theTextField resignFirstResponder]; return YES; } - (void)dealloc { [username_TextField release]; [password_TextField release]; [super dealloc]; } @end Menu.h #import <UIKit/UIKit.h> @class Menu; @interface Menu : UIViewController { UILabel *l1; UIButton *AccountSummary_Button; UIButton *PayOffQuote_Button; UIButton *PayBill_Button; UIButton *Logout_Button; UINavigationController *nv1; } @property(nonatomic,retain) IBOutlet UILabel *l1; @property(nonatomic,retain) IBOutlet UIButton *AccountSummary_Button; @property(nonatomic,retain) IBOutlet UIButton *PayOffQuote_Button; @property(nonatomic,retain) IBOutlet UIButton *PayBill_Button; @property(nonatomic,retain) IBOutlet UIButton *Logout_Button; @property (nonatomic, retain) IBOutlet UINavigationController *nv1; -(IBAction)ViewAccountSummary_method:(id)sender; -(IBAction)ViewPayOffQuote_method:(id)sender; -(IBAction)ViewPayBill_method:(id)sender; -(IBAction)Logout_method:(id)sender; @end Menu.m

    Read the article

  • Const-correctness semantics in C++

    - by thirtythreeforty
    For fun and profit™, I'm writing a trie class in C++ (using the C++11 standard.) My trie<T> has an iterator, trie<T>::iterator. (They're all actually functionally const_iterators, because you cannot modify a trie's value_type.) The iterator's class declaration looks partially like this: template<typename T> class trie<T>::iterator : public std::iterator<std::bidirectional_iterator_tag, T> { friend class trie<T>; struct state { state(const trie<T>* const node, const typename std::vector<std::pair<typename T::value_type, std::unique_ptr<trie<T>>>>::const_iterator& node_map_it ) : node{node}, node_map_it{node_map_it} {} // This pointer is to const data: const trie<T>* node; typename std::vector<std::pair<typename T::value_type, std::unique_ptr<trie<T>>>>::const_iterator node_map_it; }; public: typedef const T value_type; iterator() =default; iterator(const trie<T>* node) { parents.emplace(node, node->children.cbegin()); // ... } // ... private: std::stack<state> parents; // ... }; Notice that the node pointer is declared const. This is because (in my mind) the iterator should not be modifying the node that it points to; it is just an iterator. Now, elsewhere in my main trie<T> class, I have an erase function that has a common STL signature--it takes an iterator to data to erase (and returns an iterator to the next object). template<typename T> typename trie<T>::iterator trie<T>::erase(const_iterator it) { // ... // Cannot modify a const object! it.parents.top().node->is_leaf = false; // ... } The compiler complains because the node pointer is read-only! The erase function definitely should modify the trie that the iterator points to, even though the iterator shouldn't. So, I have two questions: Should iterator's constructors be public? trie<T> has the necessary begin() and end() members, and of course trie<T>::iterator and trie<T> are mutual friends, but I don't know what the convention is. Making them private would solve a lot of the angst I'm having about removing the const "promise" from the iterator's constructor. What are the correct const semantics/conventions regarding the iterator and its node pointer here? Nobody has ever explained this to me, and I can't find any tutorials or articles on the Web. This is probably the more important question, but it does require a good deal of planning and proper implementation. I suppose it could be circumvented by just implementing 1, but it's the principle of the thing!

    Read the article

  • how to read data from file into array? java

    - by lox
    I need some help reading data from a txt file into my ArrayList. I know the code is pretty messy, but just try to take a look at it. The first part with the creating and putting the ArrayList into the txt file works perfectly. I just need some help at the end in the "marked" area. Sorry if I still have some words in my native language, but I didn't really had the time to translate everything. public class ContAngajat { String username; String password; } public class CreazaCont { // creating the arraylist and putting it into a file public static void ang(String args[]) { ArrayList<ContAngajat> angajati=new ArrayList<ContAngajat>(50); Scanner diskScanner = new Scanner(in); Scanner forn = new Scanner(in); int n; out.print("Introduceti numarul de conturi noi care doriti sa le introduceti: "); n=forn.nextInt(); out.println(); try{ FileWriter fw = new FileWriter("ConturiAngajati.txt", true); for(int i=0; i<n; i++){ ContAngajat cont = new ContAngajat(); out.print("Username: "); cont.username=diskScanner.nextLine(); out.print("Password: "); cont.password=diskScanner.nextLine(); angajati.add(cont); fw.write(cont.username + " "); fw.write(cont.password +"|"); } fw.close(); } catch(IOException ex){ System.out.println("Could not write to file"); System.exit(0); } for (int i=0; i<n; i++) { out.println("username: " + angajati.get(i).username + " password: " +angajati.get(i).password ); } } // HERE I'M TRING TO GET THE ARRAYLIST OUT OF THE FILE public static void RdAng(String args[]) { ArrayList<ContAngajat> angajati=new ArrayList<ContAngajat>(50); ContAngajat cont = new ContAngajat(); int count,i2,i; try{ FileReader fr = new FileReader("ConturiAngajati.txt"); BufferedReader br = new BufferedReader(fr); String line = ""; while((line=br.readLine())!=null) { String[] theline=line.split("|"); count=theline.length; for(i=0;i<theline.length;i++) { String[] theword = theline[i].split(" "); } } for(i2=0;i2<count;i2++) { ContAngajat contrd = new ContAngajat(); // "ERROR" OVER HERE for (int ird=0; ird <theword.length; ird++) { cont.username=theword[0]; cont.password=theword[1]; // they keep telling me "theword cannot be resolved" whenever i try to run this } angajati.add(contrd); } } catch(IOException ex){ System.out.println("Could not read to file"); System.exit(0); } } }

    Read the article

  • Is it possible to reference a linkbotton outside an update panel as the update trigger?

    - by Selase
    I have a page based on a master page and as such i can only see the content place holders i used in the master page showing up in the aspx pages based on the master page. the source code shown below: <%@ Page Title="" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="CaseAdmin.aspx.cs" Inherits="Prototype4.CaseAdmin" %> <%@PreviousPageType VirtualPath="~/Account/Login.aspx"%> <asp:Content ID="Content1" ContentPlaceHolderID="HeadContent" runat="server"> </asp:Content> <asp:Content ID="CaseRightNews" ContentPlaceHolderID="RightNewsItem" runat="server"> </asp:Content> <asp:Content ID="CaseLeftNav" ContentPlaceHolderID="LeftNavigation" runat="server"> <div style="margin-top:20px; margin-bottom:20px;"> <p class="actionButton"> <asp:LinkButton ID="OpenCaseLinkButton" runat="server" onclick="OpenCaseLinkButton_Click">Open Case</asp:LinkButton> </p> <p class="actionButton"><asp:LinkButton ID="RegisterExhibitLinkButton" runat="server" onclick="RegisterExhibitLinkButton_Click">Register Exhibit</asp:LinkButton> </p> </div> </asp:Content> <asp:Content ID="CaseMainContnt" ContentPlaceHolderID="MainContent" runat="server"> <asp:ScriptManager ID="ScriptManager" runat="server" /> <asp:UpdatePanel ID="CaseMainCntntUpdatePanel" UpdateMode="Conditional" runat="server"> <Triggers> <asp:AsyncPostBackTrigger ControlID="" eventname="Click"/> </Triggers> <ContentTemplate> <%--Some text here to inform user to click on the open case botton to display open case form--%> </ContentTemplate> </asp:UpdatePanel> <asp:UpdatePanel runat="server" id="UpdatePanel1" updatemode="Conditional"> <Triggers> <asp:AsyncPostBackTrigger ControlID="" eventname="Click"/> </Triggers> <ContentTemplate> <%--some text here to inform users to click on the add exhibit botton to display add exhibit form--%> </ContentTemplate> </asp:UpdatePanel> </asp:Content> the section of the entire page i wish to change upon update is the (this is the main content of the page). for this reason i placed the updatepanel inside the content place holder since it cant be sitting outside and not wrapped in a content place holder. However, the buttons that i wish to apply the trigger that fires the update to, are in another content place holder(). How can i possibly get those buttons to act as the trigger while changing only what appears in the main content area. Plus, i tried getting the updatepanel to work just so i could see if it does the update well but it turned out really bad. i added some linkbottons in the content template area and used them as the triggers for testing reasons. i tested and the changes took over the entire page in contrast to just appearing in the content area. I actually just wanted to load a form that is created in another asp. page into the main content area... I seriously need help with this... Every little help, detail and information is dearly appreciated... thanks so much in advance

    Read the article

  • Why is my NSURLConnection so slow?

    - by Bama91
    I have setup an NSURLConnection using the guidelines in Using NSURLConnection from the Mac OS X Reference Library, creating an NSMutableURLRequest as POST to a PHP script with a custom body to upload 20 MB of data (see code below). Note that the post body is what it is (line breaks and all) to exactly match an existing desktop implementation. When I run this in the iPhone simulator, the post is successful, but takes an order of magnitude longer than if I run the equivalent code locally on my Mac in C++ (20 minutes vs. 20 seconds, respectively). Any ideas why the difference is so dramatic? I understand that the simulator will give different results than the actual device, but I would expect at least similar results. Thanks const NSUInteger kDataSizePOST = 20971520; const NSString* kServerBDC = @"WWW.SOMEURL.COM"; const NSString* kUploadURL = @"http://WWW.SOMEURL.COM/php/test/upload.php"; const NSString* kUploadFilename = @"test.data"; const NSString* kUsername = @"testuser"; const NSString* kHostname = @"testhost"; srandom(time(NULL)); NSMutableData *uniqueData = [[NSMutableData alloc] initWithCapacity:kDataSizePOST]; for (unsigned int i = 0 ; i < kDataSizePOST ; ++i) { u_int32_t randomByte = ((random() % 95) + 32); [uniqueData appendBytes:(void*)&randomByte length:1]; } NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init]; [request setURL:[NSURL URLWithString:kUploadURL]]; [request setHTTPMethod:@"POST"]; NSString *boundary = @"aBcDd"; NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundary]; [request addValue:contentType forHTTPHeaderField: @"Content-Type"]; NSMutableData *postbody = [NSMutableData data]; [postbody appendData:[[NSString stringWithFormat:@"--%@\nContent-Size:%d",boundary,[uniqueData length]] dataUsingEncoding:NSUTF8StringEncoding]]; [postbody appendData:[[NSString stringWithFormat:@"\nContent-Disposition: form-data; name=test; filename=%@", kUploadFilename] dataUsingEncoding:NSUTF8StringEncoding]]; [postbody appendData:[[NSString stringWithString:@";\nContent-Type: multipart/mixed;\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]]; [postbody appendData:[NSData dataWithData:uniqueData]]; [postbody appendData:[[NSString stringWithFormat:@"--%@\nContent-Size:%d",boundary,[kUsername length]] dataUsingEncoding:NSUTF8StringEncoding]]; [postbody appendData:[[NSString stringWithFormat:@"\nContent-Disposition: inline; name=Username;\n\r\n%@",kUsername] dataUsingEncoding:NSUTF8StringEncoding]]; [postbody appendData:[[NSString stringWithFormat:@"--%@\nContent-Size:%d",boundary,[kHostname length]] dataUsingEncoding:NSUTF8StringEncoding]]; [postbody appendData:[[NSString stringWithFormat:@"\nContent-Disposition: inline; name=Hostname;\n\r\n%@",kHostname] dataUsingEncoding:NSUTF8StringEncoding]]; [postbody appendData:[[NSString stringWithFormat:@"\n--%@--",boundary] dataUsingEncoding:NSUTF8StringEncoding]]; [request setHTTPBody:postbody]; NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:request delegate:self]; if (theConnection) { _receivedData = [[NSMutableData data] retain]; } else { // Inform the user that the connection failed. } [request release]; [uniqueData release];

    Read the article

  • Singleton method not getting called in Cocos2d

    - by jini
    I am calling a Singleton method that does not get called when I try doing this. I get no errors or anything, just that I am unable to see the CCLOG message. Under what reasons would a compiler not give you error and not allow you to call a method? [[GameManager sharedGameManager] openSiteWithLinkType:kLinkTypeDeveloperSite]; The method is defined as follows: -(void)openSiteWithLinkType:(LinkTypes)linkTypeToOpen { CCLOG(@"WE ARE IN openSiteWithLinkType"); //I NEVER SEE THIS MESSAGE NSURL *urlToOpen = nil; if (linkTypeToOpen == kLinkTypeDeveloperSite) { urlToOpen = [NSURL URLWithString:@"http://somesite.com"]; } if (![[UIApplication sharedApplication]openURL:urlToOpen]) { CCLOG(@"%@%@",@"Failed to open url:",[urlToOpen description]); [self runSceneWithID:kMainMenuScene]; } } HERE IS THE CODE TO MY SINGLETON: #import "GameManager.h" #import "MainMenuScene.h" @implementation GameManager static GameManager* _sharedGameManager = nil; @synthesize isMusicON; @synthesize isSoundEffectsON; @synthesize hasPlayerDied; +(GameManager*) sharedGameManager { @synchronized([GameManager class]) { if (!_sharedGameManager) { [[self alloc] init]; return _sharedGameManager; } return nil; } } +(id)alloc { @synchronized ([GameManager class]) { NSAssert(_sharedGameManager == nil,@"Attempted to allocate a second instance of the Game Manager singleton"); _sharedGameManager = [super alloc]; return _sharedGameManager; } return nil; } -(id)init { self = [super init]; if (self != nil) { //Game Manager initialized CCLOG(@"Game Manager Singleton, init"); isMusicON = YES; isSoundEffectsON = YES; hasPlayerDied = NO; currentScene = kNoSceneUninitialized; } return self; } -(void) runSceneWithID:(SceneTypes)sceneID { SceneTypes oldScene = currentScene; currentScene = sceneID; id sceneToRun = nil; switch (sceneID) { case kMainMenuScene: sceneToRun = [MainMenuScene node]; break; default: CCLOG(@"Unknown Scene ID, cannot switch scenes"); return; break; } if (sceneToRun == nil) { //Revert back, since no new scene was found currentScene = oldScene; return; } //Menu Scenes have a value of < 100 if (sceneID < 100) { if (UI_USER_INTERFACE_IDIOM() != UIUserInterfaceIdiomPad) { CGSize screenSize = [CCDirector sharedDirector].winSizeInPixels; if (screenSize.width == 960.0f) { //iPhone 4 retina [sceneToRun setScaleX:0.9375f]; [sceneToRun setScaleY:0.8333f]; CCLOG(@"GM: Scaling for iPhone 4 (retina)"); } else { [sceneToRun setScaleX:0.4688f]; [sceneToRun setScaleY:0.4166f]; CCLOG(@"GM: Scaling for iPhone 3G or older (non-retina)"); } } } if ([[CCDirector sharedDirector] runningScene] == nil) { [[CCDirector sharedDirector] runWithScene:sceneToRun]; } else { [[CCDirector sharedDirector] replaceScene:sceneToRun]; } } -(void)openSiteWithLinkType:(LinkTypes)linkTypeToOpen { CCLOG(@"WE ARE IN openSiteWithLinkType"); NSURL *urlToOpen = nil; if (linkTypeToOpen == kLinkTypeDeveloperSite) { urlToOpen = [NSURL URLWithString:@"http://somesite.com"]; } if (![[UIApplication sharedApplication]openURL:urlToOpen]) { CCLOG(@"%@%@",@"Failed to open url:",[urlToOpen description]); [self runSceneWithID:kMainMenuScene]; } } -(void) test { CCLOG(@"this is test"); } @end

    Read the article

  • iphone web service access

    - by malleswar
    Hi, I have .net webservice methods login and summary. After getting the result from login, I need to show second view and need to call summary method. I am following this tutorial. http://icodeblog.com/2008/11/03/iphone-programming-tutorial-intro-to-soap-web-services/ I created two new classes loginaccess.h and loginaccess.m. @implementation LoginAccess @synthesize ResultString,webData, soapResults, xmlParser; -(NSString*)LoginCheck:(NSString*)userName:(NSString*)pwd { NSString *soapMessage = [NSString stringWithFormat: @"\n" "\n" "\n" "\n" "%@" "%@" "" "\n" "\n",userName,pwd ]; NSLog(soapMessage); NSURL *url = [NSURL URLWithString:@"http://www.XXXXXXXXX.com/service.asmx"]; NSMutableURLRequest *theRequest = [NSMutableURLRequest requestWithURL:url]; NSString *msgLength = [NSString stringWithFormat:@"%d", [soapMessage length]]; [theRequest addValue: @"text/xml; charset=utf-8" forHTTPHeaderField:@"Content-Type"]; [theRequest addValue: @"http://XXXXXXXXm/Login" forHTTPHeaderField:@"SOAPAction"]; [theRequest addValue: msgLength forHTTPHeaderField:@"Content-Length"]; [theRequest setHTTPMethod:@"POST"]; [theRequest setHTTPBody: [soapMessage dataUsingEncoding:NSUTF8StringEncoding]]; NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:theRequest delegate:self]; if( theConnection ) { webData = [[NSMutableData data] retain]; } else { NSLog(@"theConnection is NULL"); } //[nameInput resignFirstResponder]; return ResultString; } -(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response { [webData setLength: 0]; } -(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data { [webData appendData:data]; } -(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error { NSLog(@"ERROR with theConenction"); [connection release]; [webData release]; } -(void)connectionDidFinishLoading:(NSURLConnection *)connection { NSLog(@"DONE. Received Bytes: %d", [webData length]); NSString *theXML = [[NSString alloc] initWithBytes: [webData mutableBytes] length:[webData length] encoding:NSUTF8StringEncoding]; NSLog(theXML); [theXML release]; if( xmlParser ) { [xmlParser release]; } xmlParser = [[NSXMLParser alloc] initWithData: webData]; [xmlParser setDelegate: self]; [xmlParser setShouldResolveExternalEntities: YES]; [xmlParser parse]; [connection release]; [webData release]; } -(void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *) namespaceURI qualifiedName:(NSString *)qName attributes: (NSDictionary *)attributeDict { if( [elementName isEqualToString:@"LoginResult"]) { if(!soapResults) { soapResults = [[NSMutableString alloc] init]; } recordResults = TRUE; } } -(void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string { if( recordResults ) { [soapResults appendString: string]; } } -(void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName { if( [elementName isEqualToString:@"LoginResult"]) { recordResults = FALSE; ResultString = soapResults; NSLog(@"Login"); [VariableStore setStr:ResultString]; NSLog(soapResults); [soapResults release]; soapResults = nil; } } @end I am calling LoginCheck method and based on result I want to show the second view. Here after finishing of the button touch down event, it enter into did end element, so I am always getting nil value. If I use the same code controller it works fine as I push second view controller in didendelement. Please give me some samples to place the web service calls in differnt class and how to call them in viewcontrollers. Regards, Malleswar

    Read the article

  • MVC: returning multiple results on stream connection to implement HTML5 SSE

    - by eddo
    I am trying to set up a lightweight HTML5 Server-Sent Event implementation on my MVC 4 Web, without using one of the libraries available to implement sockets and similars. The lightweight approach I am trying is: Client side: EventSource (or jquery.eventsource for IE) Server side: long polling with AsynchController (sorry for dropping here the raw test code but just to give an idea) public class HTML5testAsyncController : AsyncController { private static int curIdx = 0; private static BlockingCollection<string> _data = new BlockingCollection<string>(); static HTML5testAsyncController() { addItems(10); } //adds some test messages static void addItems(int howMany) { _data.Add("started"); for (int i = 0; i < howMany; i++) { _data.Add("HTML5 item" + (curIdx++).ToString()); } _data.Add("ended"); } // here comes the async action, 'Simple' public void SimpleAsync() { AsyncManager.OutstandingOperations.Increment(); Task.Factory.StartNew(() => { var result = string.Empty; var sb = new StringBuilder(); string serializedObject = null; //wait up to 40 secs that a message arrives if (_data.TryTake(out result, TimeSpan.FromMilliseconds(40000))) { JavaScriptSerializer ser = new JavaScriptSerializer(); serializedObject = ser.Serialize(new { item = result, message = "MSG content" }); sb.AppendFormat("data: {0}\n\n", serializedObject); } AsyncManager.Parameters["serializedObject"] = serializedObject; AsyncManager.OutstandingOperations.Decrement(); }); } // callback which returns the results on the stream public ActionResult SimpleCompleted(string serializedObject) { ServerSentEventResult sar = new ServerSentEventResult(); sar.Content = () => { return serializedObject; }; return sar; } //pushes the data on the stream in a format conforming HTML5 SSE public class ServerSentEventResult : ActionResult { public ServerSentEventResult() { } public delegate string GetContent(); public GetContent Content { get; set; } public int Version { get; set; } public override void ExecuteResult(ControllerContext context) { if (context == null) { throw new ArgumentNullException("context"); } if (this.Content != null) { HttpResponseBase response = context.HttpContext.Response; // this is the content type required by chrome 6 for server sent events response.ContentType = "text/event-stream"; response.BufferOutput = false; // this is important because chrome fails with a "failed to load resource" error if the server attempts to put the char set after the content type response.Charset = null; string[] newStrings = context.HttpContext.Request.Headers.GetValues("Last-Event-ID"); if (newStrings == null || newStrings[0] != this.Version.ToString()) { string value = this.Content(); response.Write(string.Format("data:{0}\n\n", value)); //response.Write(string.Format("id:{0}\n", this.Version)); } else { response.Write(""); } } } } } The problem is on the server side as there is still a big gap between the expected result and what's actually going on. Expected result: EventSource opens a stream connection to the server, the server keeps it open for a safe time (say, 2 minutes) so that I am protected from thread leaking from dead clients, as new message events are received by the server (and enqueued to a thread safe collection such as BlockingCollection) they are pushed in the open stream to the client: message 1 received at T+0ms, pushed to the client at T+x message 2 received at T+200ms, pushed to the client at T+x+200ms Actual behaviour: EventSource opens a stream connection to the server, the server keeps it open until a message event arrives (thanks to long polling) once a message is received, MVC pushes the message and closes the connection. EventSource has to reopen the connection and this happens after a couple of seconds. message 1 received at T+0ms, pushed to the client at T+x message 2 received at T+200ms, pushed to the client at T+x+3200ms This is not OK as it defeats the purpose of using SSE as the clients start again reconnecting as in normal polling and message delivery gets delayed. Now, the question: is there a native way to keep the connection open after sending the first message and sending further messages on the same connection?

    Read the article

  • weighted RNG speed problem in C++

    - by supert
    I have a (fast) bit of C++ code that samples cards from a 52 card deck: void sample_allcards(int table[5], int holes[], int players) { int temp[5 + 2 * players]; bool try_again; int c, n, i; for (i = 0; i < 5 + 2 * players; i++) { try_again = true; while (try_again == true) { try_again = false; c = fast_rand52(); // reject collisions for (n = 0; n < i + 1; n++) { try_again = (temp[n] == c) || try_again; } temp[i] = c; } } copy_cards(table, temp, 5); copy_cards(holes, temp + 5, 2 * players); } I am implementing code to sample the hole cards according to a known distribution (stored as a 2d table). My code for this looks like: void sample_allcards_weighted(double weights[][HOLE_CARDS], int table[5], int holes[], int players) { // weights are distribution over hole cards int temp[5 + 2 * players]; int n, i; // table cards for (i = 0; i < 5; i++) { bool try_again = true; while (try_again == true) { try_again = false; int c = fast_rand52(); // reject collisions for (n = 0; n < i + 1; n++) { try_again = (temp[n] == c) || try_again; } temp[i] = c; } } for (int player = 0; player < players; player++) { // hole cards according to distribution i = 5 + 2 * player; bool try_again = true; while (try_again == true) { try_again = false; // weighted-sample c1 and c2 at once double w[1326]; memcpy(w, weights[player], sizeof(w)); // h is a number < 1325 int h = weighted_randi(w, HOLE_CARDS); // i2h uses h and sets temp[i] to the 2 cards implied by h i2h(&temp[i], h); // reject collisions for (n = 0; n < i; n++) { try_again = (temp[n] == temp[i]) || (temp[n] == temp[i+1]) || try_again; } } } copy_cards(table, temp, 5); copy_cards(holes, temp + 5, 2 * players); } My problem? The weighted sampling algorithm is a factor of 10 slower. Speed is very important for my application. Is there a way to improve the speed of my algorithm to something more reasonable? Am I doing something wrong in my implementation? Thanks.

    Read the article

  • Setting hidden input value in Javascript, then accessing it in codebehind

    - by Siegesmith
    I have been trying to set the value of a hidden input by using Javascript and then access the value from within my C# codebehind. When I run the code that is copied below, the value that is assigned to assignedIDs is "", which I assume is the default value for a hidden input. If I manually set the value in the html tag, then assignedIDs is set to that value. This behavior suggests to me that the value of the input is being reset (re-rendered?) between the onClientClick and onClick events firing. I would appreciate any help with the matter. I have spent hours trying to solve what seems like a very simple problem. html/javascript: <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title>Admin Page - Manage Tasks</title> <script language="javascript" type="text/javascript"> function PopulateAssignedIDHiddenInput() { var source = document.getElementById('assignedLinguistListBox'); var s = ""; var count = source.length; for (var i = count - 1; i >= 0; i--) { var item = source.options[i]; if (s == "") { s = source.options[i].value; } else { s = s.concat(",",source.options[i].value); } } document.getElementById('assignedIDHiddenInput').Value = s; // I have confirmed that, at this point, the value of // the hidden input is set properly } </script> </head> <body> <form id="form1" runat="server"> <div> <asp:Panel id="EditMode" runat="server"> <table style="border: none;"> <tr> <td> <asp:Label ID="availableLinguistLabel" runat="server" Text="Available"></asp:Label><br /> <asp:ListBox ID="availableLinguistListBox" runat="server" Rows="10" SelectionMode="Multiple"></asp:ListBox> </td> <td> <input type="button" name="right" value="&gt;&gt;" onclick="Javascript:MoveItem('availableLinguistListBox', 'assignedLinguistListBox');" /><br /><br /> <input type="button" name="left" value="&lt;&lt;" onclick="Javascript:MoveItem('assignedLinguistListBox', 'availableLinguistListBox');" /> </td> <td> <asp:Label ID="assignedLinguistLabel" runat="server" Text="Assigned To"></asp:Label><br /> <asp:ListBox ID="assignedLinguistListBox" runat="server" Rows="10" SelectionMode="Multiple"></asp:ListBox> </td> </tr> </table> //-snip- <asp:Button ID="save_task_changes_button" runat="server" ToolTip="Click to save changes to task" Text="Save Changes" OnClick="save_task_changes_button_click" OnClientClick="Javascript:PopulateAssignedIDHiddenInput()" /> </asp:Panel> <!-- Hidden Inputs --> <!-- Note that I have also tried setting runat="server" with no change --> <input id="assignedIDHiddenInput" name="assignedIDHiddenInput" type="hidden" /> </div> </form> </body> c# protected void save_task_changes_button_click(object sender, EventArgs e) { string assignedIDs = Request.Form["assignedIDHiddenInput"]; // Here, assignedIDs == ""; also, Request.Params["assignedIDHiddenInput"] == "" // -snip- }

    Read the article

< Previous Page | 771 772 773 774 775 776 777 778 779 780 781 782  | Next Page >