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  • URL equals and checking Internet access

    - by James P.
    On http://java.sun.com/j2se/1.5.0/docs/api/java/net/URL.html it states that: Compares this URL for equality with another object. If the given object is not a URL then this method immediately returns false. Two URL objects are equal if they have the same protocol, reference equivalent hosts, have the same port number on the host, and the same file and fragment of the file. Two hosts are considered equivalent if both host names can be resolved into the same IP addresses; else if either host name can't be resolved, the host names must be equal without regard to case; or both host names equal to null. Since hosts comparison requires name resolution, this operation is a blocking operation. Note: The defined behavior for equals is known to be inconsistent with virtual hosting in HTTP. According to this, equals will only work if name resolution is possible. Since I can't be sure that a computer has internet access at a given time, should I just use Strings to store addresses instead? Also, how do I go about testing if access is available when requested?

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  • Toggle two divs and classes

    - by kuswantin
    I have two links with classes (login-form and register-form) relevant to their target forms ID, they want to toggle. I have also a predefined 'slideToggle' function to toggle better. This is what I have tried so far: $('#userbar a').click(function() { var c = $(this).attr('class'); $('#userbar a').removeClass('active'); $(this).toggleClass('active'); $('#register-form,#login-form').hide(); //bad, causing flashy $('#' + c).slideToggle('slow'); return false; }); With this I have trouble with the flashy window, and to correctly toggle the active classes when another link is clicked, the other link should not have active class anymore. Additional problem is the link is dead on serial clicks. I have another try, longer one: $('#userbar a').click(function() { var c = $(this).attr('class'); switch (c) { case 'login-form': $('#' + c).slideToggle('slow'); $(this).toggleClass('active'); $('#register-form').hide(); break; case 'register-form': $('#' + c).slideToggle('slow'); $(this).toggleClass('active'); $('#login-form').hide(); break; } return false; }); This one is worse than the first :( Any suggestion to correct the behavior? What I want is when a link with class login-form is click, so toggle the form with ID login-form, and hide the register-form if open. Any help would be very much appreciated. Thanks.

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  • How best to associate code with events in jQuery?

    - by Ned Batchelder
    Suppose I have a <select> element on my HTML page, and I want to run some Javascript when the selection is changed. I'm using jQuery. I have two ways to associate the code with the element. Method 1: jQuery .change() <select id='the_select'> <option value='opt1'>One</option> <option value='opt2'>Two</option> </select> <script> $('#the_select').change(function() { alert('Changed!'); }); </script> Method 2: onChange attribute <select id='the_select' onchange='selectChanged();'> <option value='opt1'>One</option> <option value='opt2'>Two</option> </select> <script> function selectChanged() { alert('Changed!'); } </script> I understand the different modularity here: for example, method 1 keeps code references out of the HTML, but method 2 doesn't need to mention HTML ids in the code. What I don't understand is: are there operational differences between these two that would make me prefer one over the other? For example, are there edge-case browsers where one of these works and the other doesn't? Is the integration with jQuery better for either? Does the late-binding of the code to the event make a difference in the behavior of the page? Which do you pick and why?

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  • Jquery click event propagation

    - by ozsenegal
    I've a table with click events bind to it rows (tr). Also,there're A elements with it owns click events assigned inside those rows. Problem is when i click on A element,it also fires click event from TD.And Im dont want this behavior,i just want to fire A click's event. Code: //Event row TR $("tr:not(:first)").click(function(){ $(".window,.backFundo,.close").remove(); var position = $(this).offset().top; position = position < 0 ? 20 : position; $("body").append($("<div></div>").addClass("backFundo")); $("body").append($("<div></div>").addClass("window").html("<span class=close><img src=Images/close.png id=fechar /></span>").append("<span class=titulo>O que deseja fazer?</span><span class=crud><a href=# id=edit>Editar</a></span><span class=crud><a href=# id=delete codigo=" + $(this).children("td:first").html() + ">Excluir</a></span>").css({top:"20px"}).fadeIn("slow")); $(document).scrollTop(0); }); //Element event $("a").live("click",function(){alert("clicked!");}); Whenever you click the anchor it fires event from it parent row.Any ideas?

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  • Why does my Jabber bot only work if I'm debugging my Perl script?

    - by TheGNUGuy
    I am trying to make a jabber bot from scratch and my script is acting funny. I was originally developing the bot on a remote CentOS box, but I have switched to a local Win7 machine. Right now I'm using ActiveState Perl and I'm using Eclipse with the Perl plugin to run a debug the script. The funny behavior I'm experiencing occurs when I run or debug the script. If I run the script using the debugger it works fine, meaning I can send messages to the bot and it can send messages to me. However when I just execute the script normally the bot sends the successful connection message then it disconnects from my jabber server and the script ends. I'm a novice when it comes to Perl and I can't figure out what I'm doing wrong. My guess is it has something to do with the subroutines and sending the presence of the bot. (I know for sure that it has something to do with sending the bot's presence because if the presence code is removed, the script behaves as expected except the bot doesn't appear to be online.) If anyone can help me with this that would be great. I originally had everything in 1 file but separated them into several trying to figure out my problem here are the pastebin links to my source code. jabberBot.pl: http://pastebin.com/cVifv0mm chatRoutine.pm: http://pastebin.com/JXmMT7av trimSpaces.pm: http://pastebin.com/SkeuWtu1 Thanks again for any help!

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  • Strongly Typed DataSet column requires custom type to implement IXmlSerializable?

    - by Phil
    I have a strongly typed Dataset with a single table with three columns. These columns all contain custom types. DataColumn1 is of type Parent DataColumn2 is of type Child1 DataColumn3 is of type Child2 Here is what these classes look like: [Serializable] [XmlInclude(typeof(Child1)), XmlInclude(typeof(Child2))] public abstract class Parent { public int p1; } [Serializable] public class Child1 :Parent { public int c1; } [Serializable] public class Child2 : Parent { public int c1; } now, if I add a row with DataColumn1 being null, and DataColumns 2 and 3 populated and try to serialize it, it works: DataSet1 ds = new DataSet1(); ds.DataTable1.AddDataTable1Row(null, new Child1(), new Child2()); StringBuilder sb = new StringBuilder(); using (StringWriter writer = new StringWriter(sb)) { ds.WriteXml(writer);//Works! } However, if I try to add a value to DataColumn1, it fails: DataSet1 ds = new DataSet1(); ds.DataTable1.AddDataTable1Row(new Child1(), new Child1(), new Child2()); StringBuilder sb = new StringBuilder(); using (StringWriter writer = new StringWriter(sb)) { ds.WriteXml(writer);//Fails! } Here is the Exception: "Type 'WindowsFormsApplication4.Child1, WindowsFormsApplication4, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' does not implement IXmlSerializable interface therefore can not proceed with serialization." I have also tried using the XmlSerializer to serialize the dataset, but I get the same exception. Does anyone know of a way to get around this where I don't have to implement IXmlSerializable on all the Child classes? Alternatively, is there a way to implement IXmlSerializable keeping all default behavior the same (ie not having any class specific code in the ReadXml and WriteXml methods)

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  • Who likes #regions in Visual Studio?

    - by Nicholas
    Personally I can't stand region tags, but clearly they have wide spread appeal for organizing code, so I want to test the temperature of the water for other MS developer's take on this idea. My personal feeling is that any sort of silly trick to simplify code only acts to encourage terrible coding behavior, like lack of cohesion, unclear intention and poor or incomplete coding standards. One programmer told me that code regions helped encourage coding standards by making it clear where another programmer should put his or her contributions. But, to be blunt, this sounds like a load of horse manure to me. If you have a standard, it is the programmer's job to understand what that standard is... you should't need to define it in every single class file. And, nothing is more annoying than having all of your code collapsed when you open a file. I know that cntrl + M, L will open everything up, but then you have the hideous "hash region definition" open and closing lines to read. They're just irritating. My most stead fast coding philosophy is that all programmer should strive to create clear, concise and cohesive code. Region tags just serve to create noise and redundant intentions. Region tags would be moot in a well thought out and intentioned class. The only place they seem to make sense to me, is in automatically generated code, because you should never have to read that outside of personal curiosity.

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  • Getting element position in IE versus other browsers

    - by Channel72
    We all know IE6 is difficult. But there seems to be disparate behavior in positioning in later versions of IE as well, when compared with Firefox or other browsers. I have a simple pair of javascript functions which finds the position of an element, and then displays another element in relation to the first element. The idea is to get the second element, which is somewhat larger, to appear in front of the first element when the mouse hovers over it. It works fine, except on all versions of Internet Explorer, the position of the second element appears different than in Firefox. The code to get the position of an element is: function getPosition(e) { var left = 0; var top = 0; while (e.offsetParent) { left += e.offsetLeft; top += e.offsetTop; e = e.offsetParent; } left += e.offsetLeft; top += e.offsetTop; return {x:left, y:top}; } And the actual rollover display code is: var pos = getPosition(elem1); elem2.style.top = pos.y - 8; elem2.style.left = pos.x - 6; In Firefox, elem2 appears directly over elem1, as I want it to. But in IE7 or IE8 it appears way off. What is the reason this occurs, and is there a way to fix it?

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  • Message driven bean not responding until client method is complete

    - by poijoi
    Hi, I have a MDB deployed on Jboss 4.2.2 and a client on the same server that produces messages and expects a reply from the MDB via a temporary queue created before the message is sent. When I run the client, I see that it creates the message, puts it in the queue and waits for the reply (no problem so far) ... but when I check in the logs I see that the timeout is reached and no response is received. When the timeout occurs and the client's method is complete the MDB starts processing the message that should have been processed the moment the client put it in the queue. As a consequence of this timing issue, when the MDB tries to reply to the temp queue, it fails since the client is already gone. If I run the same client from a remote server, I have no problem... The MDB picks up the message from the queue right away and the client receives its response right after the processing is complete. I'm using container managed transactions. I suspect it has something to do with that... I think the client's "send message/receive reply" might be all be considered a transaction before it commits to put the message in the queue... but I'm not sure if this is correct. If this is the case, why did I not see the same behavior from the remote client? is client managed transaction the default setting and that's what my remote server was using? Any idea how to fix this? Thanks in advance! PJ

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  • Visibility of reintroduced constructor

    - by avenmore
    I have reintroduced the form constructor in a base form, but if I override the original constructor in a descendant form, the reintroduced constructor is no longer visible. type TfrmA = class(TForm) private FWndParent: HWnd; public constructor Create(AOwner: TComponent; const AWndParent: Hwnd); reintroduce; overload; virtual; end; constructor TfrmA.Create(AOwner: TComponent; const AWndParent: Hwnd); begin FWndParent := AWndParent; inherited Create(AOwner); end; type TfrmB = class(TfrmA) private public end; type TfrmC = class(TfrmB) private public constructor Create(AOwner: TComponent); override; end; constructor TfrmC.Create(AOwner: TComponent); begin inherited Create(AOwner); end; When creating: frmA := TfrmA.Create(nil, 0); frmB := TfrmB.Create(nil, 0); frmC := TfrmC.Create(nil, 0); // Compiler error My work-around is to override the reintroduced constructor or to declare the original constructor overloaded, but I'd like to understand the reason for this behavior. type TfrmA = class(TForm) private FWndParent: HWnd; public constructor Create(AOwner: TComponent); overload; override; constructor Create(AOwner: TComponent; const AWndParent: Hwnd); reintroduce; overload; virtual; end; type TfrmC = class(TfrmB) private public constructor Create(AOwner: TComponent; const AWndParent: Hwnd); override; end;

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  • Common Lisp condition system for transfer of control

    - by Ken
    I'll admit right up front that the following is a pretty terrible description of what I want to do. Apologies in advance. Please ask questions to help me explain. :-) I've written ETLs in other languages that consist of individual operations that look something like: // in class CountOperation IEnumerable<Row> Execute(IEnumerable<Row> rows) { var count = 0; foreach (var row in rows) { row["record number"] = count++; yield return row; } } Then you string a number of these operations together, and call The Dispatcher, which is responsible for calling Operations and pushing data between them. I'm trying to do something similar in Common Lisp, and I want to use the same basic structure, i.e., each operation is defined like a normal function that inputs a list and outputs a list, but lazily. I can define-condition a condition (have-value) to use for yield-like behavior, and I can run it in a single loop, and it works great. I'm defining the operations the same way, looping through the inputs: (defun count-records (rows) (loop for count from 0 for row in rows do (signal 'have-value :value `(:count ,count @,row)))) The trouble is if I want to string together several operations, and run them. My first attempt at writing a dispatcher for these looks something like: (let ((next-op ...)) ;; pick an op from the set of all ops (loop (handler-bind ((have-value (...))) ;; records output from operation (setq next-op ...) ;; pick a new next-op (call next-op))) But restarts have only dynamic extent: each operation will have the same restart names. The restart isn't a Lisp object I can store, to store the state of a function: it's something you call by name (symbol) inside the handler block, not a continuation you can store for later use. Is it possible to do something like I want here? Or am I better off just making each operation function explicitly look at its input queue, and explicitly place values on the output queue?

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  • Show NSSegmentedControl menu when segment clicked, despite having set action

    - by Justin Williams
    I have an NSSegmentedControl on my UI with 4 buttons. The control is connected to a method that will call different methods depending on which segment is clicked: - (IBAction)performActionFromClick:(id)sender { NSInteger selectedSegment = [sender selectedSegment]; NSInteger clickedSegmentTag = [[sender cell] tagForSegment:selectedSegment]; switch (clickedSegmentTag) { case 0: [self showNewEventWindow:nil]; break; case 1: [self showNewTaskWindow:nil]; break; case 2: [self toggleTaskSplitView:nil]; break; case 3: [self showGearMenu]; break; } } Segment 4 has has a menu attached to it in the awakeFromNib method. I'd like this menu to drop down when the user clicks the segment. At this point, it only will drop if the user clicks & holds down on the menu. From my research online this is because of the connected action. I'm presently working around it by using some code to get the origin point of the segment control and popping up the context menu using NSMenu's popUpContextMenu:withEvent:forView but this is pretty hacktastic and looks bad compared to the standard behavior of having the menu drop down below the segmented control cell. Is there a way I can have the menu drop down as it should after a single click rather than doing the hacky context menu thing?

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  • __toString magic and type coercion

    - by TomcatExodus
    I've created a Template class for managing views and their associated data. It implements Iterator and ArrayAccess, and permits "sub-templates" for easy usage like so: <p><?php echo $template['foo']; ?></p> <?php foreach($template->post as $post): ?> <p><?php echo $post['bar']; ?></p> <?php endforeach; ?> Anyways, rather than using inline core functions, such as hash() or date(), I figured it would be useful to create a class called TemplateData, which would act as a wrapper for any data stored in the templates. This way, I can add a list of common methods for formatting, for example: echo $template['foo']->asCase('upper'); echo $template['bar']->asDate('H:i:s'); //etc.. When a value is set via $template['foo'] = 'bar'; in the controllers, the value of 'bar' is stored in it's own TemplateData object. I've used the magic __toString() so when you echo a TemplateData object, it casts to (string) and dumps it's value. However, despite the mantra controllers and views should not modify data, whenever I do something like this: $template['foo'] = 1; echo $template['foo'] + 1; //exception It dies on a Object of class TemplateData could not be converted to int; Unless I recast $template['foo'] to a string: echo ((string) $template['foo']) + 1; //outputs 2 Sort of defeats the purpose having to jump through that hoop. Are there any workarounds for this sort of behavior that exist, or should I just take this as it is, an incidental prevention of data modification in views?

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  • MUD (game) design concept question about timed events.

    - by mudder
    I'm trying my hand at building a MUD (multiplayer interactive-fiction game) I'm in the design/conceptualizing phase and I've run into a problem that I can't come up with a solution for. I'm hoping some more experienced programmers will have some advice. Here's the problem as best I can explain it. When the player decides to perform an action he sends a command to the server. the server then processes the command, determines whether or not the action can be performed, and either does it or responds with a reason as to why it could not be done. One reason that an action might fail is that the player is busy doing something else. For instance, if a player is mid-fight and has just swung a massive broadsword, it might take 3 seconds before he can repeat this action. If the player attempts to swing again to soon, the game will respond indicating that he must wait x seconds before doing that. Now, this I can probably design without much trouble. The problem I'm having is how I can replicate this behavior from AI creatures. All of the events that are being performed by the server ON ITS OWN, aka not as an immediate reaction to something a player has done, will have to be time sensitive. Some evil monster has cast a spell on you but must wait 30 seconds before doing it again... I think I'll probably be adding all these events to some kind of event queue, but how can I make that event queue time sensitive?

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  • JQuery checkbox state is updated differently between group click() and $.each(obj.click())

    - by teerapap
    The code below doesn't work in the same behavior. The sequence of click event and calling foo() is different. I want to know why they behave different sequence between call click() and iterate the objects before call click() on each. <script type="text/javascript"> function foo(obj){ alert(obj.id+" ->"+obj.checked); } function clickAll(val){ if (val) { $(":checkbox").click(); } else { $(":checkbox").each(function(i,obj){ obj.click(); }); } } </script> </head> <body> <input type="checkbox" id="check1" onclick="foo(this)" /> a <input type="checkbox" id="check2" onclick="foo(this)" /> b <input type="checkbox" id="check3" onclick="foo(this)" /> c <input type="button" onclick="clickAll(true)" value="click all" /> <input type="button" onclick="clickAll(false)" value="click all each" /> </body>

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  • jQuery & Prototype Conflict

    - by DPereyra
    Hi, I am using the jQuery AutoComplete plugin in an html page where I also have an accordion menu which uses prototype. They both work perfectly separately but when I tried to implement both components in a single page I get an error that I have not been able to understand. uncaught exception: [Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIDOMViewCSS.getComputedStyle]" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: file:///C:/Documents and Settings/Administrator/Desktop/website/js/jquery-1.2.6.pack.js :: anonymous :: line 11" data: no] I found out the file conflicting with jQuery is 'effects.js' which is used by the accordion menu. I tried replacing this file with a newer version but newer seems to break the accordion behavior. My guess is that the 'effects.js' file used in the accordion was modified to obtain the accordion demo output. I also tried using the overriding methods jQuery needs to avoid conflict with other libraries and that did not work. I obtained the accordion demo from the following site: http://www.stickmanlabs.com/accordion/ And the jQuery AutoComplete can be obtained from: http://docs.jquery.com/Plugins/Autocomplete#Setup Has any one else experienced this issue? Thanks.

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  • wsdl xml parsing , maxlength problem after encoding of text

    - by MichaelD
    We are working together with another firm. our application communicates with the other application through WCF on our side and a custom implemented java wsdl handler on the other side. They specify the wsdl format and one of the rules is that a specific string cannot contain more then 15 characters. (normally it's 60, but i take 15 for easy example reasons) When we try to send the following string to them we get an error that the string is too long according to the wsdl: "example & test" this is a string of 14 characters, so it should be allowed the microsoft wcf parser translates this to "example &amp; test" . This encoded string is 18 characters long. Now what is the standaard behavior to check a maxlength defined in a message? Is it the encoded message or the decoded message? I would think it's the decoded message , but i ain't sure. If it is the encoded message, how should we handle this so we would know how we have to split the string?

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  • Plot vectors with labels in matlab

    - by mad
    I have a Nx62 matrix with N 62-D vectors and a NX1 vector with the labels for the vectors. I am trying to plot these vectors with their labels because I want to see the behavior of these classes when plotted in a 62-dimensional space. The vectors belong to three classes according to the labels of a NX1 vector cited before. How to to that in matlab? when i do plot(vector,classes) the result is very weird to analyse, how to put labels in the graph? The code i am using to get the labels, vectors and plotting is the following: %labels is a vector with labels, vectors is a matrix where each line is a vector [labels,vectors]=libsvmread('features-im1.txt'); when I plot a three dimensional vector is simple a=[1,2,3] plot(a) and then I get the result but now i have a set of vectors and a set of labels, and i want to see the distribution of them, i want to plot each of these labels but also want to identify their classes. How to do that in matlab? EDIT: This code is almost working. The problem is the fact that for each vector and class the plot will assign a color. I just want three colors and three labels, one per class. [class,vector]=libsvmread('features-im1.txt'); %the plot doesn't allow negative and 0 values in the label class=class+2; labels = {'class -1','class 0','class 1'}; h = plot(vector); legend(h,labels{class})

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  • Is there a way to touch-enable scrolling in a WPF ScrollViewer?

    - by Brian Sullivan
    I'm trying to create a form in a WPF application that will allow the user to use iPhone-like gestures to scroll through the available fields. So, I've put all my form controls inside a StackPanel inside a ScrollViewer, and the scrollbar shows up as expected when there are too many elements to be shown on the screen. However, when I try to test this on my touch-enabled device, a panning gesture (placing a finger down on the surface and dragging it upward) does not move the viewable area down as I would expect. When I simply put a number of elements inside a ListView, the touch gestures work just fine. Is there any way to enable the same kind of behavior in a ScrollViewer? My window is structured like this: <Window x:Class="TestTouchScrolling.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="350" Width="525" Loaded="Window_Loaded"> <Grid> <ScrollViewer Name="viewer" VerticalScrollBarVisibility="Auto"> <StackPanel Name="panel"> <StackPanel Orientation="Horizontal"> <Label>Label 1:</Label> <TextBox Name="TextBox1"></TextBox> </StackPanel> <StackPanel Orientation="Horizontal"> <Label>Label 2:</Label> <TextBox Name="TextBox2"></TextBox> </StackPanel> <StackPanel Orientation="Horizontal"> <Label>Label 3:</Label> <TextBox Name="TextBox3"></TextBox> </StackPanel> <!-- Lots more like these --> </StackPanel> </ScrollViewer> </Grid>

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  • How to know why an animation stutters?

    - by Patrick Klug
    I have a few fairly simple animations (moving text around, moving ellipses etc.) and running in full screen (1920x1080 minus the task bar) the WPF Performance Suite reports a good framerate around 50 FPS throughout the animation. Dirty Rect Addition is somewhere around 300 rect/s, the SW frames are between 0 and 4 and the HW frames are between 3 and 5. Video memory usage is around 80 MB. Problem is that the animations stutters every other half second. My machine is a new Dell laptop XPS 15 with the GeForce GT 435 with 2GB memory. - The drivers are up to date. (The same behavior occurs on my netbook (in full screen) as well so I don't think it is hardware related.) If I make the window smaller the stutter goes away. The stutter occurs with the simplest of animations - even with just a couple of elements but adding more elements certainly makes it more noticeable. How can I find out what causes this stutter? When I think of it, I have not actually seen any WPF animations which run smoothly in full screen. Is this even possible?

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  • Cocoa document-based app: Notification not always received by observer

    - by roysolay
    Hi, I hope somebody can help with my notification problem. I have a notification which looks to be set up correctly but it isn’t delivered as expected. I am developing a document based app. The delegate/ document class posts the notification when it reads from a saved file: [[NSNotificationCenter defaultCenter] postNotificationName:notifyBsplinePolyOpened object:self]; Logging tells me that this line is reached whenever I open a saved document. In the DrawView class, I have observers for the windowOpen notification and the bsplinePoly file open notification: [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(mainWindowOpen:) name:NSWindowDidBecomeMainNotification object:nil]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(savedBspline:) name:notifyBsplinePolyOpened object:nil]; - (void) mainWindowOpen:(NSNotification*) note { NSLog(@"Window opened"); _mainWindow = [note object]; } - (void) savedBspline:(NSNotification*) note { NSLog(@"savedBspline called"); NSLog(@"note is %@", [note name]); } The behavior is odd. When I save and close the main window and reopen it, I get the “Window opened” message but not the “savedBspline called” message. If I leave a main window open and open a previously saved session, I get the “Window opened” message and the “savedBspline called” message. I have searched online discussion and Apple DevCenter documentation but I have not seen this problem.

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  • Am I a discoverer of a bug in the WPF engine?

    - by bitbonk
    We have a MFC 8 application compiled with /CLR that contains a larger amount of Windows Forms UserControls wich again contain WPF user controls using ElementHost. Due to the architecture of our software we can not use HwndHost directly. We observed an extremely strange behavior here that we can not make any sense of: When the CPU load is very high during startup of the application and there are a lot live of ElementHost instances, the whole property engine completely stops working. For example animations that usually just work fine now never update the values of the bound properties, they just stay at some random value after startup. When I set a property that is not bound to anything the value is correctly stored in the dependency property (calling the getter returns the new value) but the visual representation never reflects that. I set the background to red but the background color does not change. We tested this on a lot of different machines all running Windows XP SP2 and it is pretty reproducible. The funny thing here is, that there is in fact one situation where the bound properties actually pickup a new value from the animation and the visual gets updated based on the property values. It is when I resize the ElementHost or when I hide and reshow the parent native control. As soon as I do this, properties that are bound to an animation pickup a new value and the visuals rerender based on the new property values - but just once - if I want to see another update I have to resize the ElementHost. Do you have any explanation of what could be happening here or how I could approach this problem to find it out? What can I do to debug this? Is there a way I can get more information about what WPF actually does or where WPF might have crashed? To me it currently seems like a bug in WPF itself since it only happens at high CPU load at startup.

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  • Function with parameter type that has a copy-constructor with non-const ref chosen?

    - by Johannes Schaub - litb
    Some time ago I was confused by the following behavior of some code when I wanted to write a is_callable<F, Args...> trait. Overload resolution won't call functions accepting arguments by non-const ref, right? Why doesn't it reject in the following because the constructor wants a Test&? I expected it to take f(int)! struct Test { Test() { } // I want Test not be copyable from rvalues! Test(Test&) { } // But it's convertible to int operator int() { return 0; } }; void f(int) { } void f(Test) { } struct WorksFine { }; struct Slurper { Slurper(WorksFine&) { } }; struct Eater { Eater(WorksFine) { } }; void g(Slurper) { } void g(Eater) { } // chooses this, as expected int main() { // Error, why? f(Test()); // But this works, why? g(WorksFine()); } Error message is m.cpp: In function 'int main()': m.cpp:33:11: error: no matching function for call to 'Test::Test(Test)' m.cpp:5:3: note: candidates are: Test::Test(Test&) m.cpp:2:3: note: Test::Test() m.cpp:33:11: error: initializing argument 1 of 'void f(Test)' Can you please explain why one works but the other doesn't?

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  • Reordering methods in ComImport interfaces throws COMException (0x80041001)

    - by Ohad Schneider
    Consider the following code for COM interop with internet shortcuts: [ComImport] [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] [Guid("CABB0DA0-DA57-11CF-9974-0020AFD79762")] public interface IUniformResourceLocatorW { void SetUrl([MarshalAs(UnmanagedType.LPWStr)] string pcszUrl, int dwInFlags); void GetUrl([MarshalAs(UnmanagedType.LPWStr)] out StringBuilder ppszUrl); void InvokeCommand(IntPtr purlici); } [ComImport] [Guid("FBF23B40-E3F0-101B-8488-00AA003E56F8")] public class InternetShortcut { } The following works as expected: var ishort = new InternetShortcut(); ((IPersistFile)ishort).Load("MyLink.url", 0); ((IUniformResourceLocatorW)ishort).GetUrl(out url); However: If I comment out IUniformResourceLocatorW.SetUrl (which I am not using), IUniformResourceLocatorW.GetUrl throws a COMException (HResult 0x80041001). If I switch between IUniformResourceLocatorW.SetUrl and IUniformResourceLocatorW.GetUrl (that is place the former below the latter) the same exception is thrown If I comment out IUniformResourceLocatorW.InvokeCommand the code runs fine. It's as if the order has to be preserved "up to" the invoked method. Is this behavior by design? documented somewhere? I'm asking because some COM interfaces are composed of many methods with possibly many supporting types and I'd rather avoid defining what I don't need if possible.

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  • Why are symbols not frozen strings?

    - by Alex Chaffee
    I understand the theoretical difference between Strings and Symbols. I understand that Symbols are meant to represent a concept or a name or an identifier or a label or a key, and Strings are a bag of characters. I understand that Strings are mutable and transient, where Symbols are immutable and permanent. I even like how Symbols look different from Strings in my text editor. What bothers me is that practically speaking, Symbols are so similar to Strings that the fact that they're not implemented as Strings causes a lot of headaches. They don't even support duck-typing or implicit coercion, unlike the other famous "the same but different" couple, Float and Fixnum. The mere existence of HashWithIndifferentAccess, and its rampant use in Rails and other frameworks, demonstrates that there's a problem here, an itch that needs to be scratched. Can anyone tell me a practical reason why Symbols should not be frozen Strings? Other than "because that's how it's always been done" (historical) or "because symbols are not strings" (begging the question). Consider the following astonishing behavior: :apple == "apple" #=> false, should be true :apple.hash == "apple".hash #=> false, should be true {apples: 10}["apples"] #=> nil, should be 10 {"apples" => 10}[:apples] #=> nil, should be 10 :apple.object_id == "apple".object_id #=> false, but that's actually fine All it would take to make the next generation of Rubyists less confused is this: class Symbol < String def initialize *args super self.freeze end (and a lot of other library-level hacking, but still, not too complicated) See also: http://onestepback.org/index.cgi/Tech/Ruby/SymbolsAreNotImmutableStrings.red http://www.randomhacks.net/articles/2007/01/20/13-ways-of-looking-at-a-ruby-symbol Why does my code break when using a hash symbol, instead of a hash string? Why use symbols as hash keys in Ruby? What are symbols and how do we use them? Ruby Symbols vs Strings in Hashes Can't get the hang of symbols in Ruby

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