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  • Can't empty JS array....

    - by solefald
    Yes, I am having issues with this very basic (or so it seems) thing. I am pretty new to JS and still trying to get my head around it, but I am pretty familiar with PHP and have never experienced anything like this. I just can not empty this damn array, and stuff keeps getting added to the end every time i run this. I have no idea why, and i am starting to think that it is somehow related to the way chekbox id's are named, but i may be mistaking.... id="alias[1321-213]", id="alias[1128-397]", id="alias[77-5467]" and so on. I have tried sticking checkboxes = []; and checkboxes.length = 0; In every place possible. Right after the beginning of the function, at the end of the function, even outside, right before the function, but it does not help, and the only way to empty this array is to reload the page. Please tell me what I am doing wrong, or at least point me to a place where i can RTFM. I am completely out of ideas here. function() { var checkboxes = new Array(); checkboxes = $(':input[name="checkbox"]'); $.each(checkboxes, function(key, value) { console.log(value.id); alert(value.id); } ); checkboxes.length = 0; } I have also read Mastering Javascript Arrays 3 times to make sure I am not doing something wrong, but still can't figure it out....

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  • boost::lambda bind expressions can't get bind to string's empty() to work

    - by navigator
    Hi, I am trying to get the below code snippet to compile. But it fails with: error C2665: 'boost::lambda::function_adaptor::apply' : none of the 8 overloads could convert all the argument types. Sepcifying the return type when calling bind does not help. Any idea what I am doing wrong? Thanks. #include <boost/lambda/lambda.hpp> #include <boost/lambda/bind.hpp> #include <string> #include <map> int main() { namespace bl = boost::lambda; typedef std::map<int, std::string> types; types keys_and_values; keys_and_values[ 0 ] = "zero"; keys_and_values[ 1 ] = "one"; keys_and_values[ 2 ] = "Two"; std::for_each( keys_and_values.begin(), keys_and_values.end(), std::cout << bl::constant("Value empty?: ") << std::boolalpha << bl::bind(&std::string::empty, bl::bind(&types::value_type::second, _1)) << "\n"); return 0; }

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  • Replace apostrophe in json string with empty string

    - by user572844
    Hi, I have problem with deserialization of json string, because string is bad format. For example json object consist string property statusMessage with value "Hello "dog" ". The correct format should be "Hello \" dog \" " . I would like remove apostrophes from this property. Something Like this. "Hello "dog" ". - "Hello dog ". Here is it original json string which I work. "{\"jancl\":{\"idUser\":18438201,\"nick\":\"JANCl\",\"photo\":\"1\",\"sex\":1,\"photoAlbums\":1,\"videoAlbums\":0,\"sefNick\":\"jancl\",\"profilPercent\":75,\"emphasis\":false,\"age\":\"-\",\"isBlocked\":false,\"PHOTO\":{\"normal\":\"http://u.aimg.sk/fotky/1843/82/n_18438201.jpg?v=1\",\"medium\":\"http://u.aimg.sk/fotky/1843/82/m_18438201.jpg?v=1\",\"24x24\":\"http://u.aimg.sk/fotky/1843/82/s_18438201.jpg?v=1\"},\"PLUS\":{\"active\":false,\"activeTo\":\"0000-00-00\"},\"LOCATION\":{\"idRegion\":\"6\",\"regionName\":\"Trenciansky kraj\",\"idCity\":\"138\",\"cityName\":\"Trencianske Teplice\"},\"STATUS\":{\"isLoged\":true,\"isChating\":false,\"idChat\":0,\"roomName\":\"\",\"lastLogin\":1294925369},\"PROJECT_STATUS\":{\"photoAlbums\":1,\"photoAlbumsFavs\":0,\"videoAlbums\":0,\"videoAlbumsFavs\":0,\"videoAlbumsExts\":0,\"blogPosts\":0,\"emailNew\":0,\"postaNew\":0,\"clubInvitations\":0,\"dashboardItems\":1},\"STATUS_MESSAGE\":{\"statusMessage\":\"\"Status\"\",\"addTime\":\"1294872330\"},\"isFriend\":false,\"isIamFriend\":false}}" Problem is here, json string consist this object: "STATUS_MESSAGE": {"statusMessage":" "some "bad" value" ", "addTime" :"1294872330"} Condition of string which I want modified: string start with "statusMessage":" string can has any *lenght from 0 -N * string end with ", "addTime So I try write pattern for string which start with "statusMessage":", has any lenght and is ended with ", "addTime. Here is it: const string pattern = " \" statusMessage \" : \" .*? \",\"addTime\" "; var regex = new Regex(pattern, RegexOptions.IgnoreCase); //here i would replace " with empty string string result = regex.Replace(jsonString, match => ???); But I think pattern is wrong, also I don’t know how replace apostrophe with empty string (remove apostrophne). My goal is : "statusMessage":" "some "bad" value" to "statusMessage":" "some bad value" Thank for advice

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  • CallbackValidator called with empty string

    - by Paolo Tedesco
    I am writing a custom configuration section, and I would like to validate a configuration property with a callback, like in this example: using System; using System.Configuration; class CustomSection : ConfigurationSection { [ConfigurationProperty("stringValue", IsRequired = false)] [CallbackValidator(Type = typeof(CustomSection), CallbackMethodName = "ValidateString")] public string StringValue { get { return (string)this["stringValue"]; } set { this["stringValue"] = value; } } public static void ValidateString(object value) { if (string.IsNullOrEmpty((string)value)) { throw new ArgumentException("string must not be empty."); } } } class Program { static void Main(string[] args) { CustomSection cfg = (CustomSection)ConfigurationManager.GetSection("customSection"); Console.WriteLine(cfg.StringValue); } } And my App.config file looks like this: <?xml version="1.0" encoding="utf-8" ?> <configuration> <configSections> <section name="customSection" type="CustomSection, config-section"/> </configSections> <customSection stringValue="lorem ipsum"/> </configuration> My problem is that when the ValidateString function is called, the value parameter is always an empty string, and therefore the validation fails. If i just remove the validator, the string value is correctly initialized to the value in the configuration file. What am I missing?

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  • Editing a .class file directly, playing around with opcodes

    - by echox
    Hi, today I just tried to play a little bit around with the opcodes in compiled java class file. After inserting iinc 1,1 the java virtual machine responds with: Exception in thread "main" java.lang.ClassFormatError: Truncated class file at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632) at java.lang.ClassLoader.defineClass(ClassLoader.java:616) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141) at java.net.URLClassLoader.defineClass(URLClassLoader.java:283) at java.net.URLClassLoader.access$000(URLClassLoader.java:58) at java.net.URLClassLoader$1.run(URLClassLoader.java:197) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:190) at java.lang.ClassLoader.loadClass(ClassLoader.java:307) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:248) Could not find the main class: Test. Program will exit. This is my example source code: public class Test { public static void main(String[] args) { int i = 5; i++; i++; i++; System.out.println("Number: " + i + "\n"); } } The opcode for an increment is 0x84 + 2 bytes for operands. There's only one section in the resulting class file, which contains 0x84: [..] 8401 0184 0101 8401 01[..] So I would translate this as: iinc 1,1 iinc 1,1 iinc 1,1 corresponding to my i++; i++; i++; I then tried to append just 840101 to increment the variable once more, but that didn't work and resulted in the ClassFormatError. Is there anything like a checksum for the class file? I looked up the format of a classfile in http://java.sun.com/docs/books/jvms/second_edition/html/ClassFile.doc.html but could not find anything which points out to some kind of bytes_of_classfile or something. I also don't understand why the error is "Truncated Class File", because I did append something :-) I know its not a good idea to edit class files directly, but I'm just interested on the VM internals here.

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  • NSURLConnection and empty post variables

    - by SooDesuNe
    I'm at my wits end with this one, because I've used very similar code in the past, and it worked just fine. The following code results in empty $_POST variables on the server. I verified this with: file_put_contents('log_file_name', "log: ".$word, FILE_APPEND); the only contents of log_file_name was "log: " I then verified the PHP with a simple HTML form. It performed as expected. The Objective-C: NSString *word = "this_word_gets_lost"; NSString *myRequestString = [NSString stringWithFormat:@"word=%@", word]; [self postAsynchronousPHPRequest:myRequestString toPage:@"http://www.mysite.com/mypage.php" delegate:nil]; } -(void) postAsynchronousPHPRequest:(NSString*)request toPage:(NSString*)URL delegate:(id)delegate{ NSData *requestData = [ NSData dataWithBytes: [ request UTF8String ] length: [ request length ] ]; NSMutableURLRequest *URLrequest = [ [ NSMutableURLRequest alloc ] initWithURL: [ NSURL URLWithString: URL ] ]; [ URLrequest setHTTPMethod: @"POST" ]; [ URLrequest setHTTPBody: requestData ]; [ NSURLConnection connectionWithRequest:URLrequest delegate:delegate]; [URLrequest release]; } The PHP: $word = $_POST['word']; file_put_contents('log_file_name', "log: ".$word, FILE_APPEND); What am I doing wrong in the Objective-C that would cause the $_POST variable to be empty on the server?

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  • Cant' cast a class with multiple inheritance

    - by Jay S.
    I am trying to refactor some code while leaving existing functionality in tact. I'm having trouble casting a pointer to an object into a base interface and then getting the derived class out later. The program uses a factory object to create instances of these objects in certain cases. Here are some examples of the classes I'm working with. // This is the one I'm working with now that is causing all the trouble. // Some, but not all methods in NewAbstract and OldAbstract overlap, so I // used virtual inheritance. class MyObject : virtual public NewAbstract, virtual public OldAbstract { ... } // This is what it looked like before class MyObject : public OldAbstract { ... } // This is an example of most other classes that use the base interface class NormalObject : public ISerializable // The two abstract classes. They inherit from the same object. class NewAbstract : public ISerializable { ... } class OldAbstract : public ISerializable { ... } // A factory object used to create instances of ISerializable objects. template<class T> class Factory { public: ... virtual ISerializable* createObject() const { return static_cast<ISerializable*>(new T()); // current factory code } ... } This question has good information on what the different types of casting do, but it's not helping me figure out this situation. Using static_cast and regular casting give me error C2594: 'static_cast': ambiguous conversions from 'MyObject *' to 'ISerializable *'. Using dynamic_cast causes createObject() to return NULL. The NormalObject style classes and the old version of MyObject work with the existing static_cast in the factory. Is there a way to make this cast work? It seems like it should be possible.

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  • Case class copy() method abstraction.

    - by Joa Ebert
    I would like to know if it is possible to abstract the copy method of case classes. Basically I have something like sealed trait Op and then something like case class Push(value: Int) extends Op and case class Pop() extends Op. The first problem: A case class without arguments/members does not define a copy method. You can try this in the REPL. scala> case class Foo() defined class Foo scala> Foo().copy() <console>:8: error: value copy is not a member of Foo Foo().copy() ^ scala> case class Foo(x: Int) defined class Foo scala> Foo(0).copy() res1: Foo = Foo(0) Is there a reason why the compiler makes this exception? I think it is rather unituitive and I would expect every case class to define a copy method. The second problem: I have a method def ops: List[Op] and I would like to copy all ops like ops map { _.copy() }. How would I define the copy method in the Op trait? I get a "too many arguments" error if I say def copy(): this.type. However, since all copy() methods have only optional arguments: why is this incorrect? And, how do I do that correct? By making another method named def clone(): this.type and write everywhere def clone() = copy() for all the case classes? I hope not.

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  • jquery load returns empty, possible MVC 2 problem?

    - by Max Fraser
    I have a site that need to get some data from a different sit that is using asp.net MVC/ The data to get loaded is from these pages: http://charity.hondaclassic.com/home/totaldonations http://charity.hondaclassic.com/Home/CharityList This should be a no brainer but for some reason I get an empty response, here is my JS: <script> jQuery.noConflict(); jQuery(document).ready(function($){ $('.totalDonations').load('http://charity.hondaclassic.com/home/totaldonations'); $('#charityList').load('http://charity.hondaclassic.com/home/CharityList'); }); </script> in firebug I see the request is made and come back with a response of 200 OK but the response is empty, if you browse to these pages they work fine! What the heck? Here are the controller actions from the MVC site: public ActionResult TotalDonations() { var total = "$" + repo.All<Customer>().Sum(x => x.AmountPaid).ToString(); return Content(total); } public ActionResult CharityList() { var charities = repo.All<Company>(); return View(charities); } Someone please out what stupid little thing I am missing - this should have taken me 5 minutes and it's been hours!

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  • Attachment empty/blank when sending mail using phpmailer

    - by chupinette
    Hello! I am using phpmailer class to send email and i am attaching a file to the mail. The email is sent successfully but the attachment which is an sql file is empty which should not be the case. I have tried with an image file, but it seems that every file that i attach is empty. Can anyone help me solve this problem please? $mail = new PHPMailer(); $body = "Reminder"; $mail->IsSMTP(); $mail->Host = "mail.yourdomain.com"; $mail->SMTPDebug = 1; $mail->SMTPAuth = true; $mail->SMTPSecure = "ssl"; $mail->Host = "smtp.gmail.com"; $mail->Port = 465; $mail->Username = "[email protected]"; $mail->Password = "abc"; $mail->SetFrom('[email protected]', 'blbla'); $mail->AddReplyTo("[email protected]","First Last"); $mail->Subject = "Your order has been successfully placed" $mail->MsgHTML($body); $mail->AddAddress("[email protected]","xyz"); $mail->AddAttachment("D:\b2\shop3.sql","shop3.sql"); I have tried to display the size of the file before attaching it, and it actually displays the file size. Can anyone help me please?

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  • Independent name of a class

    - by tobi
    We have class lua. In lua class there is a method registerFunc() which is defined: void lua::registerFun() { lua_register( luaState, "asd", luaApi::asd); lua_register( luaState, "zxc", luaApi::zxc); } lua_register is a built-in function from lua library: http://pgl.yoyo.org/luai/i/lua_register it takes static methods from luaApi class as an 3rd argument. Now some programmer wants to use the lua class, so he is forced to create his own class with definitions of the static methods, like: class luaApi { public: static int asd(); static int zxc(); }; and now is the point. I don't want (as a programmer) to create class named exactly "luaApi", but e.g. myClassForLuaApi. But for now it's not possible because it is explicitly written in the code - in lua class: lua_register( luaState, "asd", luaApi::asd); I would have to change it to: lua_register( luaState, "asd", myClassForLuaApi::asd); but I don't want to (let's assume that the programmer has no access there). If it's still not understandable, I give up. :) Thanks.

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  • How to set an empty value using XPath?

    - by Ricardo
    Using this xml example: <templateitem itemid="5"> <templateitemdata>%ARN%</templateitemdata> </templateitem> <templateitem itemid="6"> <templateitemdata></templateitemdata> </templateitem> I am using XPath to get and set Node values. The code I am using to get the nodes is: private static Node ***getNode***(Document doc, String XPathQuery) throws XPathExpressionException { XPath xpath = XPathFactory.newInstance().newXPath(); XPathExpression expr = xpath.compile(XPathQuery); Object result = expr.evaluate(doc, XPathConstants.NODESET); NodeList nodes = (NodeList) result; if(nodes != null && nodes.getLength() >0) return nodes.item(0); throw new XPathExpressionException("No node list found for " + XPathQuery); } To get %ARN% value: "//templateitem[@itemid=5]/templateitemdata/text()" and with the getNode method I can get the node, and then call the getNodeValue(). Besides getting that value, I would like to set templateitemdata value for the "templateitem[@itemid=6]" since its empty. But the code I use can't get the node since its empty. The result is null. Do you know a way get the node so I can set the value?

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  • Count the no of LI then add class to parent UL.

    - by Wazdesign
    <ul class="taglib-ratings thumbs"> <li id="qezr_yourRating"> <a href="javascript:;" class="rating rate-up "></a> </li> </ul> <ul class="taglib-ratings thumbs"> <li id="qezr_yourRating"> <a href="javascript:;" class="rating rate-up "></a> </li> <li id="qezr_yourRating"> <a href="javascript:;" class="rating rate-up "></a> </li> </ul> I want to apply the class to the UL on base of the Count of the Inner LIs. Like if it has two LI then the class should be like two-thumbs Like if it has one LI then the class should be like one-thumbs I am trying this JS but not working it returns 2 jQuery(document).ready(function(){ var countLi = $(".taglib-ratings > li").size(); alert(countLi); if(countLi == 2) { $(this).parent('.taglib-ratings').addClass('2-col'); alert ('this ul has 2 li'); } else if(countLi == 1) { $(this).parent('.taglib-ratings').addClass('2-col'); alert ('this ul has 1 li'); } else if(countLi > 2) { alert ('this ul has'+ countLi +' li'); } }); Here is the JSbin link to the same. http://jsbin.com/ofeda/edit

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  • Use .bat file to recursively loop through folders and get hold of .class files

    - by user320550
    HI all, This is what i'm trying to do. I have a .bat file which takes in a argument which is nothing but a folder name. What i do first is go one level up (cd ..). Now in this directory i have 3 folders and each folders have sub-folders and have .class files in them. What i want to do is recursively loop through the folders and get hold of the .class files. Once this is done i want to echo the target folder of the .class file as well as echo the name of the.class file. So c:\temp\potter\myclass.class. I would echo out c:\temp\potter\ and myclass. I'm able to do this by writing a separate bat file which works. But when i integrate this with the recursive function it seems to break. This is what i'm doing: :: call the junit classes... and save the results echo step 3... cd %1 cd .. for /r %%a in (*.class) do set Var=%%a echo Full file location %Var% for %%i in ("%Var%") do Set CF=%%~dpi Set CF=%CF:~0,-1% :LOOP If "%CF:~-1,1%"=="\" GoTo :DONE Set CF=%CF:~0,-1% GoTo :LOOP :DONE Set CF=%CF:~0,-1% echo Folder Location %CF% ::cd %CF% For %%j in ("%Var%") Do Set name=%%~nxj :: -6 because of Quotations Set name=%name:~0,-6% echo File Name %name% echo step 3 complete... However i only get the output of one directory, while i have multiple directories having .class files. This is the output i get: step 3... Full file location C:\NKCV\Project\MyActivities\6_Selenium\htmlTestCasesConve rted2JUnit\iexplore\flow2\testCase_app2.class Folder Location C:\NKCV\Project\MyActivities\6_Selenium\htmlTestCasesConverte d2JUnit\iexplore\flow2 File Name testCase_app2 step 3 complete... missing argument! usage htmltestCaseLocation for eg., "C:\NKCV\Project\MyActivities\6_Selenium\htmlTestCases" Could anyone please let me know whats wrong here? Thanks.

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  • Empty Postbacks on ASP.NET pages

    - by AaronLS
    We are having a problem that seems to only be a problem when accessing our websites from internal intranet machines. When logged into the domain, and accessing our websites, postbacks are not working. Basically the page behaves as if it were refreshed and nothing was changed. When logging the GETs and POSTs with an HTTP analyzer, the post is complete empty and the ContentLength is 0. It is also very sporadic, but seems to be happening fairly often. In the case where it failed, we could see that there was an extra item in the Header for the POST, it was "Authorization" and the value was the word "Negotiate " followed by a space and then a bunch of characters and two equal symbols at the end, which looked like some kind of base64 encoded value. In a case where it succeeded, this Authorization item was no in the header, but I have logged more than one successful cases to know if that is consistent. We have seen this occur only with IE8 so far, and when it occurs it is sometimes sporadic. I can close and open the browser and it will begin working sometimes, and other times it is still broken. What might be causing the postback to be empty? This means the viewstate is not sent to the server which makes the page basically broken. It seems to certainly be a client side issue, but not sure if it's not aggravated by some server settings. Thanks in advance.

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  • Apply a specific class to the first item in a series with PHP

    - by Thomas
    I have a php script that echoes a series of uploaded images and I need to apply a class to the first image echoed in the series. Is this possible? For example, if I want to display 10 images and apply a class to only the first image, how would I go about it? Here is the code, I am working with: <div id="gallery"> <?php query_posts('cat=7'); while(have_posts()) { the_post(); $image_tag = wp_get_post_image('return_html=true'); $resized_img = getphpthumburl($image_tag,'h=387&w=587&zc=1'); $url = get_permalink(); $Price ='Price'; $Location = 'Location'; $title = $post->post_title; echo "<a href='$url'><img src='$resized_img' width='587' height='387' "; echo "rel=\"<div class='gallery_title'><h2>"; echo $title; echo "</h2></div>"; echo "<div class='pre_box'>Rate:</div><div class='entry'>\$"; echo get_post_meta($post->ID, $Price, true); echo "</div><div class='pre_box'>Location:</div><div class='entry'>"; echo get_post_meta($post->ID, $Location, true); echo "</div>\""; echo "'/></a>"; echo ""; } ?> On line 13, the code looks like this: echo "<a href='$url'><img src='$resized_img' width='587' height='387' "; For the first item only, I need it to look like this: echo "<a href='$url' class='show'><img src='$resized_img' width='587' height='387' ";

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  • WPF Empty Row in ItemsControl Binding with ObservableCollection

    - by YoMo
    I have ItemsControl Binding with ObservableCollection, every think is oky excipt when ObservableCollection was empty the ItemsControl showing one empty row !! <ItemsControl Visibility="Visible" ItemsSource="{Binding ocItemsinInvoice,Mode=TwoWay}" x:Name="test" Margin="10,-32,0,207" Width="412" HorizontalAlignment="Left"> <ItemsControl.ItemsPanel> <ItemsPanelTemplate> <UniformGrid Columns="1" VerticalAlignment="Top" /> </ItemsPanelTemplate> </ItemsControl.ItemsPanel> <ItemsControl.ItemTemplate> <DataTemplate> <Button x:Name="btnOpenInvoice" Style="{StaticResource OpenInvoicesButton}" FontSize="12" Width="300" Height="60" Foreground="#ff252526"> <StackPanel Orientation="Vertical"> <TextBlock Text="{Binding Item.ItemName}" HorizontalAlignment="Center" VerticalAlignment="Center" /> </StackPanel> </Button> </DataTemplate> </ItemsControl.ItemTemplate> </ItemsControl> How can I remove it?

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  • jQuery.ajax() + empty JSON object = parse error

    - by roosteronacid
    I get a parse error when using jQuery to load some JSON data. Here's a snippet of my code: jQuery.ajax({ dataType: "json", success: function (json) { jQuery.each(json, function () { alert(this["columnName"]); }); } }); I get no errors when parsing a non-empty JSON object. So my guess is that the problem is with my serializer. Question is: how do I format an empty JSON object which jQuery won't consider malformed? This is what I've tried so far, with no success: {[]} {[null]} {} {null} {"rows": []} {"rows": null} {"rows": {}} UPDATE: I can understand that I've been somewhat vague--let me try and clarify: Parsing of the JSON object is not the issue here--JQuery is - I think. jQuery throws a parse-error (invokes the error function). It seems like jQuery's internal JSON validation is not accepting any of the before mentioned objects. Not even the valid ones. Output of the error function is: XMLHttpRequest: XMLHttpRequest readyState=4 status=200 textStatus: parsererror errorThrown: undefined This goes for all of the before mentioned objects.

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  • jQuery class selectors with nested div's

    - by mboles57
    This is part of some HTML from which I need to retrieve a piece of data. The HTML is assigned to a variable called fullDescription. <p>testing</p> <div class="field field-type-text field-field-video-short-desc"> <div class="field-label">Short Description:&nbsp;</div> <div class="field-items"> <div class="field-item odd"> Demonstrates the basics of using the Content section of App Cloud Studio </div> </div> </div> <div class="field field-type-text field-field-video-id"> <div class="field-label">Video ID:&nbsp;</div> <div class="field-items"> <div class="field-item odd"> 1251462871001 </div> </div> </div> I wish to retrieve the video ID number (1251462871001). I was thinking something like this: var videoID = $(fullDescription).find(".field.field-type-text.field-field-video-id").find(".field-item.odd").html(); Although it does not generate any syntax errors, it does not retrieve the number. Thanks for helping out a jQuery noob! -Matt

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  • C++ Matrix class hierachy

    - by bpw1621
    Should a matrix software library have a root class (e.g., MatrixBase) from which more specialized (or more constrained) matrix classes (e.g., SparseMatrix, UpperTriangluarMatrix, etc.) derive? If so, should the derived classes be derived publicly/protectively/privately? If not, should they be composed with a implementation class encapsulating common functionality and be otherwise unrelated? Something else? I was having a conversation about this with a software developer colleague (I am not per se) who mentioned that it is a common programming design mistake to derive a more restricted class from a more general one (e.g., he used the example of how it was not a good idea to derive a Circle class from an Ellipse class as similar to the matrix design issue) even when it is true that a SparseMatrix "IS A" MatrixBase. The interface presented by both the base and derived classes should be the same for basic operations; for specialized operations, a derived class would have additional functionality that might not be possible to implement for an arbitrary MatrixBase object. For example, we can compute the cholesky decomposition only for a PositiveDefiniteMatrix class object; however, multiplication by a scalar should work the same way for both the base and derived classes. Also, even if the underlying data storage implementation differs the operator()(int,int) should work as expected for any type of matrix class. I have started looking at a few open-source matrix libraries and it appears like this is kind of a mixed bag (or maybe I'm looking at a mixed bag of libraries). I am planning on helping out with a refactoring of a math library where this has been a point of contention and I'd like to have opinions (that is unless there really is an objective right answer to this question) as to what design philosophy would be best and what are the pros and cons to any reasonable approach.

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  • Why initialize an object to empty

    - by ProgEnthu
    I am learning windows programming with the help of MSDN.Why would somebody initialize an object like the following? WNDCLASS wc = { }; Will this zero all the memory of the object? Whole source code is following: #ifndef UNICODE #define UNICODE #endif #include <windows.h> LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam); int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE, PWSTR pCmdLine, int nCmdShow) { // Register the window class. const wchar_t CLASS_NAME[] = L"Sample Window Class"; WNDCLASS wc = { }; wc.lpfnWndProc = WindowProc; wc.hInstance = hInstance; wc.lpszClassName = CLASS_NAME; RegisterClass(&wc); // Create the window. HWND hwnd = CreateWindowEx( 0, // Optional window styles. CLASS_NAME, // Window class L"Learn to Program Windows", // Window text WS_OVERLAPPEDWINDOW, // Window style // Size and position CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, // Parent window NULL, // Menu hInstance, // Instance handle NULL // Additional application data ); if (hwnd == NULL) { return 0; } ShowWindow(hwnd, nCmdShow); // Run the message loop. MSG msg = { }; while (GetMessage(&msg, NULL, 0, 0)) { TranslateMessage(&msg); DispatchMessage(&msg); } return 0; } LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam) { switch (uMsg) { case WM_DESTROY: PostQuitMessage(0); return 0; case WM_PAINT: { PAINTSTRUCT ps; HDC hdc = BeginPaint(hwnd, &ps); FillRect(hdc, &ps.rcPaint, (HBRUSH) (COLOR_WINDOW+1)); EndPaint(hwnd, &ps); } return 0; } return DefWindowProc(hwnd, uMsg, wParam, lParam); }

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  • Getting the full-name of the current user, returns an empty string (C#/C++)

    - by Nir
    I try to get the full-name of the current log-in user (Fullname, not username). The following code C#, C++ works fine but on XP computers not connected to the Net, I get empty string as result if I run it ~20 minutes after login (It runs OK whithin the first ~20 minutes after login) A Win32 API (GetUserNameEx) is used rather that PrincipalContext since it PrincipalContext may takes up to 15 seconds when working offline. Any Help why am I getting an empty string as result though a user full name is specified??? - C# Code public static string CurrentUserFullName { get { const int EXTENDED_NAME_FORMAT_NAME_DISPLAY = 3; StringBuilder userName = new StringBuilder(256); uint length = (uint) userName.Capacity; string ret; if (GetUserNameEx(EXTENDED_NAME_FORMAT_NAME_DISPLAY, userName, ref length)) { ret = userName.ToString(); } else { int errorCode = Marshal.GetLastWin32Error(); throw new Win32Exception("GetUserNameEx Failed. Error code - " + errorCode); } return ret; } } [DllImport("Secur32.dll", CharSet = CharSet.Auto, SetLastError = true)] private static extern bool GetUserNameEx(int nameFormat, StringBuilder lpNameBuffer, ref uint lpnSize); - Code in C++ #include "stdafx.h" #include <windows.h> #define SECURITY_WIN32 #include <Security.h> #pragma comment( lib, "Secur32.lib" ) int _tmain(int argc, _TCHAR* argv[]) { char szName[100]; ULONG nChars = sizeof( szName ); if ( GetUserNameEx( NameDisplay, szName, &nChars ) ) { printf( "Name: %s\n", szName); } else { printf( "Failed to GetUserNameEx\n" ); printf( "%d\n", GetLastError() ); } return 0; }

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  • How does object of sub-class record information about its super-class the in a Virtual Inheritance

    - by Summer_More_More_Tea
    Hi there: I encounter this problem when tackling with virtual inheritance. I remember that in a non-virtual inheritance hierarchy, object of sub-class hold an object of its direct super-class. What about virtual inheritance? In this situation, does object of sub-class hold an object of its super-class directly or just hold a pointer pointing to an object of its super-class? By the way, why the output of the following code is: sizeof(A): 8 sizeof(B): 20 sizeof(C): 32 Code: #include <iostream> using namespace std; class A{ char k[ 3 ]; public: virtual void a(){}; }; class B : public virtual A{ char j[ 3 ]; public: virtual void b(){}; }; class C : public virtual B{ char i[ 3 ]; public: virtual void c(){}; }; int main( int argc, char *argv[] ){ cout << "sizeof(A): " << sizeof( A ) << endl; cout << "sizeof(B): " << sizeof( B ) << endl; cout << "sizeof(C): " << sizeof( C ) << endl; return 0; } Thanks in advance. Kind regards.

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  • hibernate empty collection in component

    - by Jurgen H
    I have a component mapped using Hibernate. If all fields in the component in the database are null, the component itself is set to null by hibernate. This is the expected behavior and also what I need. The problem I have, is that when I add a bag to that component, the bag is initialized to an empty list. This means the component has a non null value... resulting in the component being created. Any idea how to fix this? <class name="foo.bar.Entity" table="Entity"> <id name="id" column="id"> <generator class="native" /> </id> <property name="departure" column="departure_time" /> <property name="arrival" column="arrival_time" /> <component name="statistics"> <bag name="linkStatistics" lazy="false" cascade="all" > <key column="entity_id" not-null="true" /> <one-to-many class="foo.bar.LinkStatistics" /> </bag> <property name="loggedTime" column="logged_time" /> ... </component> A criteria with Restirctions.isNull("statistics") does return the expected values.

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  • Javascript help needed - which variable is return empty??

    - by mathew
    Hi I would like to know how do I add an error check to below mentioned code...I mean how do I check if this code return empty or not?? if this returns empty then I would give a message "Not Found".. How do I do That?? google.load('search', '1'); var blogSearch; function searchComplete() { // Check that we got results document.getElementById('content').innerHTML = ''; if (blogSearch.results && blogSearch.results.length > 0) { for (var i = 0; i < blogSearch.results.length; i++) { // Create HTML elements for search results var p = document.createElement('p'); var a = document.createElement('a'); a.href = blogSearch.results[i].postUrl; a.innerHTML = blogSearch.results[i].title; // Append search results to the HTML nodes p.appendChild(a); document.body.appendChild(p); } } } function onLoad() { // Create a BlogSearch instance. blogSearch = new google.search.BlogSearch(); // Set searchComplete as the callback function when a search is complete. The // blogSearch object will have results in it. blogSearch.setSearchCompleteCallback(this, searchComplete, null); // Set a site restriction blogSearch.setSiteRestriction('blogspot.com'); // Execute search query blogSearch.execute('1974 Chevrolet Caprice'); // Include the required Google branding google.search.Search.getBranding('branding'); } // Set a callback to call your code when the page loads google.setOnLoadCallback(onLoad);

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