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  • How to keep a trace of a record inside a nested repeater?

    - by Amokrane
    Hi, I have the following implementation: As you can see I have a repeater (listing the Machines) and a nested repeater (listing the WindowsServices inside each Machine). For each Windows Service I can perform an action using a button. However, to perform this action I need to know which Machine and which WindowsService are concerned. This is my code: protected void Page_Init(object sender, EventArgs e) { rptMachine.ItemDataBound += new RepeaterItemEventHandler(rptMachine_ItemDataBound); } protected void Page_Load(object sender, EventArgs e) { // bind the Machine repeater rptMachine.DataSource = _monitoringService.Machines; rptMachine.DataBind(); } protected void rptMachine_ItemDataBound(object sender, RepeaterItemEventArgs e) { if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem) { Repeater nestedRepeater = (Repeater) e.Item.FindControl("rptWindowsService"); nestedRepeater.DataSource = ((IMachine) e.Item.DataItem).WindowsServices; nestedRepeater.DataBind(); Button btnActionInner = null; // bind the action button situated inside the nested repeater foreach(RepeaterItem ri in nestedRepeater.Items) { if((Button)ri.FindControl("btnAction") != null) { btnActionInner = (Button) ri.FindControl("btnAction"); btnActionInner.CommandName = "ActionState"; btnActionInner.CommandArgument = strWindowsService; } } } } protected void rptWindowsService_ItemCommand(object source, RepeaterCommandEventArgs e) { // do the specific action stop/run for the windows service if (e.CommandName == "ActionState") { if(((Button)(e.CommandSource)).Text.Equals("Stop")) { } else if(((Button)(e.CommandSource)).Text.Equals("Run")) { } } } } } So basically I need to know (inside rptWindowsService_ItemCommand) what is the pair that is concerned by the operation. What's the best way to do that? Don't hesitate to ask for more clarifications! Thanks

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  • What issues to consider when rolling your own data-backend for Silverlight / AJAX on non-ASP.NET ser

    - by Edward Tanguay
    I have read-only Silverlight and AJAX apps which read static text and XML files from a PHP/Apache server, which works very nicely with features such as asynchronous loading, lazy-loading only what I need for each page, loading in the background, developed a little query language to get a PHP script to create custom XML files etc. it's pragmatic read-only REST, and all works fast and fine for read-only sites. Now I want to also add the ability to write data from these apps to a database on the same PHP/Apache server. For those of you who have built similar data-access layers, what do I need to consider while building this, especially regarding security so that not just any client can write and alter my database, e.g.: check HTTP_USER_AGENT for security check REMOTE_ADDR for security require a special code for security, perhaps a list of TAN codes (such as banks use for online transactions) each which can only be used once, both the client and server have these I wonder if there is some kind of standard REST query I should lean on for e.g. building SQL-like statements in the URL parameters, e.g. http://www.thedatalayersite.com/query?insertinto=customers&... Any thoughts, notes from experience, ideas, gotchas, especially ideas on tightening down security in this endeavor would be helpful.

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  • Go: using a pointer to array

    - by Sean
    I'm having a little play with google's Go language, and I've run into something which is fairly basic in C but doesn't seem to be covered in the documentation I've seen so far When I pass a pointer to an array to a function, I presumed we'd have some way to access it as follows: func conv(x []int, xlen int, h []int, hlen int, y *[]int) for i := 0; i<xlen; i++ { for j := 0; j<hlen; j++ { *y[i+j] += x[i]*h[j] } } } But the Go compiler doesn't like this: sean@spray:~/dev$ 8g broke.go broke.go:8: invalid operation: y[i + j] (index of type *[]int) Fair enough - it was just a guess. I have got a fairly straightforward workaround: func conv(x []int, xlen int, h []int, hlen int, y_ *[]int) { y := *y_ for i := 0; i<xlen; i++ { for j := 0; j<hlen; j++ { y[i+j] += x[i]*h[j] } } } But surely there's a better way. The annoying thing is that googling for info on Go isn't very useful as all sorts of C\C++\unrelated results appear for most search terms.

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  • Normalize whitespace and other plain-text formatting routines

    - by dreftymac
    Background: The language is JavaScript. The goal is to find a library or pre-existing code to do low-level plain-text formatting. I can write it myself, but why re-invent the wheel. The issue is: it is tough to determine if a "wheel" is out there, since any search for JavaScript libraries pulls up an ocean of HTML-centric stuff. I am not interested in HTML necessarily, just text. Example: I need a JavaScript function that changes this: BEFORE: nisi ut aliquip | ex ea commodo consequat duis |aute irure dolor in esse cillum dolore | eu fugiat nulla pariatur |excepteur sint occa in culpa qui | officia deserunt mollit anim id |est laborum ... into this ... AFTER: nisi ut aliquip | ex ea commodo consequat duis | aute irure dolor in esse cillum dolore | eu fugiat nulla pariatur | excepteur sint occa in culpa qui | officia deserunt mollit anim id | est laborum Question: Does it exist, a JavaScript library that is non-html-web-development-centric that has functions for normalizing spaces in delimited plain text, justifying and spacing plain text? Rationale: Investigating JavaScript for use in a programmer's text editor.

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  • Why does my IMultiBindingConverter get an array of strings when used to set TextBox.Text?

    - by mcohen75
    Hi- I'm trying to use a MultiBinding with a converter where the child elements also have a converter. The XAML looks like so: <TextBlock> <TextBlock.Text> <MultiBinding Converter="{StaticResource localizedMessageConverter}" ConverterParameter="{x:Static res:Resources.RecordsFound}" > <Binding Converter="{StaticResource localizedMessageParameterConverter}" ConverterParameter="ALIAS" Path="Alias" Mode="OneWay" /> <Binding Converter="{StaticResource localizedMessageParameterConverter}" ConverterParameter="COUNT" Path="Count" Mode="OneWay" /> </MultiBinding> </TextBlock.Text> The problem I'm facing here is, whenever this is used with a TextBlock to specify the Text property, my IMultiValueConverter implementation gets an object collection of strings instead of the class returned by the IValueConverter. It seems that the ToString() method is called on the result of the inner converter and passed to the IMultiValueConverter. If used to specify the Content property of Label, all is well. It seems to me that the framework is assuming that the return type will be string, but why? I can see this for the MultiBinding since it should yield a result that is compatible with TextBlock.Text, but why would this also be the case for the Bindings inside a MultiBinding? If I remove the converter from the inner Binding elements, the native types are returned. In my case string and int.

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  • What should a developer know before building a public web site?

    - by Joel Coehoorn
    What things should a programmer implementing the technical details of a web site address before making the site public? If Jeff Atwood can forget about HttpOnly cookies, sitemaps, and cross-site request forgeries all in the same site, what important thing could I be forgetting as well? I'm thinking about this from a web developer's perspective, such that someone else is creating the actual design and content for the site. So while usability and content may be more important than the platform, you the programmer have little say in that. What you do need to worry about is that your implementation of the platform is stable, performs well, is secure, and meets any other business goals (like not cost too much, take too long to build, and rank as well with Google as the content supports). Think of this from the perspective of a developer who's done some work for intranet-type applications in a fairly trusted environment, and is about to have his first shot and putting out a potentially popular site for the entire big bad world wide web. Also: I'm looking for something more specific than just a vague "web standards" response. I mean, HTML, JavaScript, and CSS over HTTP are pretty much a given, especially when I've already specified that you're a professional web developer. So going beyond that, Which standards? In what circumstances, and why? Provide a link to the standard's specification. This question is community wiki, so please feel free to edit that answer to add links to good articles that will help explain or teach each particular point.

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  • Create dynamic factory method in PHP (< 5.3)

    - by fireeyedboy
    How would one typically create a dynamic factory method in PHP? By dynamic factory method, I mean a factory method that will autodiscover what objects there are to create, based on some aspect of the given argument. Preferably without registering them first with the factory either. I'm OK with having the possible objects be placed in one common place (a directory) though. I want to avoid your typical switch statement in the factory method, such as this: public static function factory( $someObject ) { $className = get_class( $someObject ); switch( $className ) { case 'Foo': return new FooRelatedObject(); break; case 'Bar': return new BarRelatedObject(); break; // etc... } } My specific case deals with the factory creating a voting repository based on the item to vote for. The items all implement a Voteable interface. Something like this: Default_User implements Voteable ... Default_Comment implements Voteable ... Default_Event implements Voteable ... Default_VoteRepositoryFactory { public static function factory( Voteable $item ) { // autodiscover what type of repository this item needs // for instance, Default_User needs a Default_VoteRepository_User // etc... return new Default_VoteRepository_OfSomeType(); } } I want to be able to drop in new Voteable items and Vote repositories for these items, without touching the implementation of the factory.

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  • How to trace the connection pool in a Java Web application - DBMS_APPLICATION_INFO

    - by Cleiton Garcia
    Hello, I need improve the traceability in a Web Application that usually run on fixed db user. The DBA should have a fast access for the information about the heavy users that are degrading the database. 5 years ago, I implemented a .NET ORM engine which makes a log of user and the server using the DBMS_APPLICATION_INFO package. Using a wrapper above the connection manager with the following code: DBMS_APPLICATION_INFO.SET_MODULE('" + User + " - " + appServerMachine + "',''); Each time that a connection get a connection from the pool, the package is executed to log the information in the V$SESSION. Has anyone discover or implemented a solution for this problem using the Toplink or Hibernate? Is there a default implementation for this problem? I found here a solutions as I implemented 5 years ago, but I'd like to know with anyone have a better solution and integrated with the ORM. http://stackoverflow.com/questions/53379/using-dbmsapplicationinfo-with-jboss My application is above Spring, the DAO are implemented with JPA (using hibernate) and actually running directly in Tomcat, with plans to (next year) migrate to SAP Netwevare Application Server. Thanks.

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  • Am I Writing Assembly Or NASM?

    - by cam
    I'm fed up with this. I've been trying to just get a grip on assembly for awhile, but I feel like I'm coding towards my compiler rather than a language. I've been using this tutorial, and so far it's giving me hell. I'm using NASM, which may be the problem, but I figured it was the most popular one. I'm simply trying to learn the most general form of assembly, so I decided to learn x86. I keep running into stupid errors, like not being able to increment a variable. Here's the latest one: not being able to use div. mov bx, 0; mov cx, 0; jmp start; start: inc cx; mov ax, cx; div 3; <-- invalid combination of opcode and operand cmp ah,0; jz totalvalue; mov ax, cx; div 5; <-- invalid combination of opcode and operand cmp ah, 0; jz totalvalue; cmp cx, 1000; jz end; totalvalue: add bx,cx; jmp start; jmp end; end: mov ah,4ch; mov al,00; int 21h; Should I change compilers? It seems like division should be standard. Do I need to read two tutorials (one on NASM, and one on x86?). Any specific help on this problem?

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  • How to get user input before saving a file in Sublime Text

    - by EddieJessup
    I'm making a plugin in Sublime Text that prompts the user for a password to encrypt a file before it's saved. There's a hook in the API that's executed before a save is executed, so my naïve implementation is: class TranscryptEventListener(sublime_plugin.EventListener): def on_pre_save(self, view): # If document is set to encode on save if view.settings().get('ON_SAVE'): self.view = view # Prompt user for password message = "Create a Password:" view.window().show_input_panel(message, "", self.on_done, None, None) def on_done(self, password): self.view.run_command("encode", {password": password}) The problem with this is, by the time the input panel appears for the user to enter their password, the document has already been saved (despite the trigger being 'on_pre_save'). Then once the user hits enter, the document is encrypted fine, but the situation is that there's a saved plaintext file, and a modified buffer filled with the encrypted text. So I need to make Sublime Text wait until the user's input the password before carrying out the save. Is there a way to do this? At the moment I'm just manually re-saving once the encryption has been done: def on_pre_save(self, view, encode=False): if view.settings().get('ON_SAVE') and not view.settings().get('ENCODED'): self.view = view message = "Create a Password:" view.window().show_input_panel(message, "", self.on_done, None, None) def on_done(self, password): self.view.run_command("encode", {password": password}) self.view.settings().set('ENCODED', True) self.view.run_command('save') self.view.settings().set('ENCODED', False) but this is messy and if the user cancels the encryption then the plaintext file gets saved, which isn't ideal. Any thoughts? Edit: I think I could do it cleanly by overriding the default save command. I hoped to do this by using the on_text_command or on_window_command triggers, but it seems that the save command doesn't trigger either of these (maybe it's an application command? But there's no on_application_command). Is there just no way to override the save function?

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  • Ordered delivery with NetNamedPipeBinding using oneWay calls

    - by Aseem Bansal
    Is it possible to guarantee ordered delivery with oneWay calls using namedPipe binding? I have a WCF service/client communicating using namedPipe binding. The client is exposing a callback contract in which all the methods in the callback are marked as OneWay. Something like this [ServiceContract(CallbackContract = typeof(IMyServiceCallback))] public interface IMyService { [OperationContract] void MyOperation(); } public interface IMyServiceCallback { [OperationContract(IsOneWay=true)] void MyCallback1(); [OperationContract(IsOneWay=true)] void MyCallback2(); } At the server side, the implementation of MyOperation method always calls MyCallback1 first and then MyCallback2 but I am observing that sometimes the client receives the calls in the incorrect order (MyCallback2 first and then MyCallback1). On searching the internet I found that the order is not guaranteed with oneway operation as mentioned here and also there is something called reliableSession which ensure message ordering. All the examples on the internet for reliable session are with TCP binding (and not a single one with NamedPipeBinding) and the tcpBinding also has a property called ReliableSession which is not present on the NetNamedPipeBinding. So I am not sure whether reliable session is expected to work with NetNamedPipeBinding or not. Question: Does reliable session work with namedPipeBinding? If yes, how? If no, Is there any other approach with which I can guarantee ordered delivery?

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  • Creating form using Generic_inlineformset_factory from the Model Form

    - by Prateek
    hello dear all, I wanted to create a edit form with the help of ModelForm. and my models contain a Generic relation b/w classes, so if any one could suggest me the view and a bit of template for the purpose I would be very thankful, as I am new to the language. My models look like:- class Employee(Person): nickname = models.CharField(_('nickname'), max_length=25, null=True, blank=True) blood_type = models.CharField(_('blood group'), max_length=3, null=True, blank=True, choices=BLOOD_TYPE_CHOICES) marital_status = models.CharField(_('marital status'), max_length=1, null=True, blank=True, choices=MARITAL_STATUS_CHOICES) nationality = CountryField(_('nationality'), default='IN', null=True, blank=True) about = models.TextField(_('about'), blank=True, null=True) dependent = models.ManyToManyField(Dependent, through='DependentRelationship') pan_card_number = models.CharField(_('PAN card number'), max_length=50, blank=True, null=True) policy_number = models.CharField(_('policy number'), max_length=50, null=True, blank=True) # code specific details user = models.OneToOneField(User, blank=True, null=True, verbose_name=_('user')) class Person(models.Model): """Person model""" title = models.CharField(_('title'), max_length=20, null=True, blank=True) first_name = models.CharField(_('first name'), max_length=100) middle_name = models.CharField(_('middle name'), max_length=100, null=True, blank=True) last_name = models.CharField(_('last name'), max_length=100, null=True, blank=True) suffix = models.CharField(_('suffix'), max_length=20, null=True, blank=True) slug = models.SlugField(_('slug'), max_length=50, unique=True) class PhoneNumber(models.Model) : phone_number = generic.GenericRelation('PhoneNumber') email_address = generic.GenericRelation('EmailAddress') address = generic.GenericRelation('Address') date_of_birth = models.DateField(_('date of birth'), null=True, blank=True) gender = models.CharField(_('gender'), max_length=1, null=True, blank=True, choices=GENDER_CHOICES) content_type = models.ForeignKey(ContentType, If anyone could suggest me a link or so. it would be a great help........

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  • TCL How to read , extract and count the occurent in .txt file (Current Directory)

    - by Passion
    Hi Folks, I am beginner to scripting and vigorously learning TCL for the development of embedded system. I have to Search for the files with only .txt format in the current directory, count the number of cases of each different "Interface # nnnn" string in .txt file, where nnnn is a four or 32 digits max hexadecimal no and o/p of a table of Interface number against occurrence. I am facing implementation issues while writing a script i.e, Unable to implement the data structure like Linked List, Two Dimensional array. I am rewriting a script using multi dimension array (Pass values into the arrays in and out of procedure) in TCL to scan through the every .txt file and search for the the string/regular expression ‘Interface # ’ to count and display the number of occurrences. If someone could help me to complete this part will be much appreciated. Search for only .txt extension files and obtain the size of the file Here is my piece of code for searching a .txt file in present directory set files [glob *.txt] if { [llength $files] > 0 } { puts "Files:" foreach f [lsort $files] { puts " [file size $f] - $f" } } else { puts "(no files)" } I reckon these are all the possible logical steps behind to complete it i) Once searched and find the .txt file then open all .txt files in read only mode ii) Create a array or list using the procedure (proc) Interface number to NULL and Interface count to zero 0 iii) Scan thro the .txt file and search for the string or regular expression "interface # iv) When a match found in .txt file, check the Interface Number and increment the count for the corresponding entry. Else add new element to the Interface Number list v) If there are no files return to the first directory My o/p is like follows Interface Frequency 123f 3 1232 4

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  • "do it all" page structure and things to watch out for?

    - by Andrew Heath
    I'm still getting my feet wet in PHP (my 1st language) and I've reached the competency level where I can code one page that handles all sorts of different related requests. They generally have a structure like this: (psuedo code) <?php include 'include/functions.php'; IF authorized IF submit (add data) ELSE IF update (update data) ELSE IF list (show special data) ELSE IF tab switch (show new area) ELSE display vanilla (show default) ELSE "must be registered/logged-in" ?> <HTML> // snip <?php echo $output; ?> // snip </HTML> and it all works nicely, and quite quickly which is cool. But I'm still sorta feeling my way in the dark... and would like some input from the pros regarding this type of page design... is it a good long-term structure? (it seems easily expanded...) are there security risks particular to this design? are there corners I should avoid painting myself into? Just curious about what lies ahead, really...

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  • Email Tracking - GMail

    - by Abs
    Hello all, I am creating my own email tracking system for email marketing tracking. I have been able to determine each persons email client they are using by using the http referrer but for some reason GMAIL does not send a HTTP_REFERRER at all! So I am trying to find another way of identifying when gmail requests a transparent image from my server. I get the following headers print_r($_SERVER);: DOCUMENT_ROOT = /usr/local/apache/htdocs GATEWAY_INTERFACE = CGI/1.1 HTTP_ACCEPT = */* HTTP_ACCEPT_CHARSET = ISO-8859-1,utf-8;q=0.7,*;q=0.3 HTTP_ACCEPT_ENCODING = gzip,deflate,sdch HTTP_ACCEPT_LANGUAGE = en-GB,en-US;q=0.8,en;q=0.6 HTTP_CONNECTION = keep-alive HTTP_COOKIE = __utmz=156230011.1290976484.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); __utma=156230011.422791272.1290976484.1293034866.1293050468.7 HTTP_HOST = xx.xxx.xx.xxx HTTP_USER_AGENT = Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.10 (KHTML, like Gecko) Chrome/8.0.552.237 Safari/534.10 PATH = /bin:/usr/bin QUERY_STRING = i=MTA= REDIRECT_STATUS = 200 REMOTE_ADDR = xx.xxx.xx.xxx REMOTE_PORT = 61296 REQUEST_METHOD = GET Is there anything of use in that list? Or is there something else I can do to actually get the http referrer, if not how are other ESPs managing to find whether gmail was used to view an email? Btw, I appreciate it if we can hold back on whether this is ethical or not as many ESPs do this already, I just don't want to pay for their service and I want to do it internally. Thanks all for any implementation advice. Update Just thought I would update this question and make it clearer in light of the bounty. I would like to find out when a user opens my email when sent to a GMail inbox. Assume, I have the usual transparent image tracking and the user does not block images. I would like to do this with the single request and the header details I get when the transparent image is requested.

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  • RANDOM Number Generation in C

    - by CVS-2600Hertz-wordpress-com
    Recently i have begun development of a simple game. It is improved version of an earlier version that i had developed. Large part of the game's success depends on Random number generation in different modes: MODE1 - Truly Random mode myRand(min,max,mode=1); Should return me a random integer b/w min & max. MODE2 - Pseudo Random : Token out of a bag mode myRand(min,max,mode=2); Should return me a random integer b/w min & max. Also should internally keep track of the values returned and must not return the same value again until all the other values are returned atleast once. MODE3 - Pseudo Random : Human mode myRand(min,max,mode=3); Should return me a random integer b/w min & max. The randomisation ought to be not purely mathematically random, rather random as user perceive it. How Humans see RANDOM. * Assume the code is time-critical (i.e. any performance optimisations are welcome) * Pseudo-code will do but an implementation in C is what i'm looking for. * Please keep it simple. A single function should be sufficient (thats what i'm looking for) Thank You

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  • What is Ruby's analog to Python Metaclasses?

    - by Sean Copenhaver
    Python has the idea of metaclasses that, if I understand correctly, allow you to modify an object of a class at the moment of construction. You are not modifying the class, but instead the object that is to be created then initialized. Python (at least as of 3.0 I believe) also has the idea of class decorators. Again if I understand correctly, class decorators allow the modifying of the class definition at the moment it is being declared. Now I believe there is an equivalent feature or features to the class decorator in Ruby, but I'm currently unaware of something equivalent to metaclasses. I'm sure you can easily pump any Ruby object through some functions and do what you will to it, but is there a feature in the language that sets that up like metaclasses do? So again, Does Ruby have something similar to Python's metaclasses? Edit I was off on the metaclasses for Python. A metaclass and a class decorator do very similar things it appears. They both modify the class when it is defined but in different manners. Hopefully a Python guru will come in and explain better on these features in Python. But a class or the parent of a class can implement a __new__(cls[,..]) function that does customize the construction of the object before it is initialized with __init__(self[,..]).

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  • Jquery Ui DatePicker, attaches to textbox but only works once, then all click events are disabled.

    - by RubbleFord
    <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title></title> <link rel="stylesheet" href="css/ui-lightness/jquery-ui-1.7.2.custom.css" type="text/css" media="all" /> <script type="text/javascript" src="js/jquery-1.3.2.min.js"></script> <script type="text/javascript" src="js/jquery-ui-1.7.2.custom.min.js"></script> <script type="text/javascript"> $(document).ready(function() { $('#date').datepicker(); }); </script> </head> <body> <%--<form id="form1" runat="server">--%> <div> <input type="text" id="date" /> </div> <%--</form>--%> </body> </html> I've attached a datepicker to a text box and the first time I click it, it works a treat and populates the text box with the current date. It works fine in IE7 Comp mode, Chrome and Firefox. It works once or twice on IE8 but locks the browser up after that. One interesting note is the host operating system is Windows 2008 R2. Any ideas?

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  • Random point on VideoDisplay isn't accurate enough

    - by Mike
    For a schoolassigment me and some buddies of mine are creating an application that is showing many similarities with the C-Mon & Kypski musicvideo on www.oneframeoffame.com. The application is being developed in Flex. We want to get a random point of a clip, let it pause so a user can mimic the pose and make a snapshot out of it. What i managed to do is get a random point of the movie. I did this by getting a random value between 0 and de total duration of the movie. But what i didn't managed to do is let the screen pause on every 24st of a frame. As the movie concist out of 24FPS. It looks like the the random value of the movie that is being requested is being rounded by the movie itself. As example: There appears to be no difference between the frames requested at 2.40 or 2.41. It appears it got something to do with keyframing i've read on the Adobe® Flex™ 3.5 Language Reference. The movie is a FLV file and i use the VideoDisplay object to display the movie. Does someone is familiar with this or knows a solution to my problem? Thanks in advance

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  • What is the right approach to checksumming UDP packets

    - by mr.b
    I'm building UDP server application in C#. I've come across a packet checksum problem. As you probably know, each packet should carry some simple way of telling receiver if packet data is intact. Now, UDP already has 2-byte checksum as part of header, which is optional, at least in IPv4 world. Alternative method is to have custom checksum as part of data section in each packet, and to verify it on receiver. My question boils down to: is it better to rely on (optional) checksum in UDP packet header, or to make a custom checksum implementation as part of packet data section? Perhaps the right answer depends on circumstances (as usual), so one circumstance here is that, even though code is written and developed in .NET on Windows, it might have to run under platform-independent Mono.NET, so eventual solution should be compatible with other platforms. I believe that custom checksum algorithm would be easily portable, but I'm not so sure about the first one. Any thoughts? Also, shouts about packet checksumming in general are welcome.

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  • documenting class properties

    - by intuited
    I'm writing a lightweight class whose properties are intended to be publicly accessible, and only sometimes overridden in specific instantiations. There's no provision in the Python language for creating docstrings for class properties, or any sort of properties, for that matter. What is the accepted way, should there be one, to document these properties? Currently I'm doing this sort of thing: class Albatross(object): """A bird with a flight speed exceeding that of an unladen swallow. Properties: """ flight_speed = 691 __doc__ += """ flight_speed (691) The maximum speed that such a bird can attain """ nesting_grounds = "Throatwarbler Man Grove" __doc__ += """ nesting_grounds ("Throatwarbler Man Grove") The locale where these birds congregate to reproduce. """ def __init__(**keyargs): """Initialize the Albatross from the keyword arguments.""" self.__dict__.update(keyargs) Although this style doesn't seem to be expressly forbidden in the docstring style guidelines, it's also not mentioned as an option. The advantage here is that it provides a way to document properties alongside their definitions, while still creating a presentable class docstring, and avoiding having to write comments that reiterate the information from the docstring. I'm still kind of annoyed that I have to actually write the properties twice; I'm considering using the string representations of the values in the docstring to at least avoid duplication of the default values. Is this a heinous breach of the ad hoc community conventions? Is it okay? Is there a better way? For example, it's possible to create a dictionary containing values and docstrings for the properties and then add the contents to the class __dict__ and docstring towards the end of the class declaration; this would alleviate the need to type the property names and values twice. I'm pretty new to python and still working out the details of coding style, so unrelated critiques are also welcome.

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  • Resolving Circular References for Objects Implementing ISerializable

    - by Chris
    I'm writing my own IFormatter implementation and I cannot think of a way to resolve circular references between two types that both implement ISerializable. Here's the usual pattern: [Serializable] class Foo : ISerializable { private Bar m_bar; public Foo(Bar bar) { m_bar = bar; m_bar.Foo = this; } public Bar Bar { get { return m_bar; } } protected Foo(SerializationInfo info, StreamingContext context) { m_bar = (Bar)info.GetValue("1", typeof(Bar)); } public void GetObjectData(SerializationInfo info, StreamingContext context) { info.AddValue("1", m_bar); } } [Serializable] class Bar : ISerializable { private Foo m_foo; public Foo Foo { get { return m_foo; } set { m_foo = value; } } public Bar() { } protected Bar(SerializationInfo info, StreamingContext context) { m_foo = (Foo)info.GetValue("1", typeof(Foo)); } public void GetObjectData(SerializationInfo info, StreamingContext context) { info.AddValue("1", m_foo); } } I then do this: Bar b = new Bar(); Foo f = new Foo(b); bool equal = ReferenceEquals(b, b.Foo.Bar); // true // Serialise and deserialise b equal = ReferenceEquals(b, b.Foo.Bar); If I use an out-of-the-box BinaryFormatter to serialise and deserialise b, the above test for reference-equality returns true as one would expect. But I cannot conceive of a way to achieve this in my custom IFormatter. In a non-ISerializable situation I can simply revisit "pending" object fields using reflection once the target references have been resolved. But for objects implementing ISerializable it is not possible to inject new data using SerializationInfo. Can anyone point me in the right direction?

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  • Invert a string: Recursion vs iteration in javascript

    - by steweb
    Hi all, one month ago I've been interviewed by some google PTO members. One of the questions was: Invert a string recursively in js and explain the running time by big O notation this was my solution: function invert(s){ return (s.length > 1) ? s.charAt(s.length-1)+invert(s.substring(0,s.length-1)) : s; } Pretty simple, I think. And, about the big-o notation, I quickly answered O(n) as the running time depends linearly on the input. - Silence - and then, he asked me, what are the differences in terms of running time if you implement it by iteration? I replied that sometimes the compiler "translate" the recursion into iteration (some programming language course memories) so there are no differences about iteration and recursion in this case. Btw since I had no feedback about this particular question, and the interviewer didn't answer "ok" or "nope", I'd like to know if you maybe agree with me or if you can explain me whether there could be differences about the 2 kind of implementations. Thanks a lot and Regards!

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  • Finding a picture in a picture with java?

    - by tarrasch
    what i want to to is analyse input from screen in form of pictures. I want to be able to identify a part of an image in a bigger image and get its coordinates within the bigger picture. Example: would have to be located in And the result would be the upper right corner of the picture in the big picture and the lower left of the part in the big picture. As you can see, the white part of the picture is irrelevant, what i basically need is just the green frame. Is there a library that can do something like this for me? Runtime is not really an issue. What i want to do with this is just generating a few random pixel coordinates and recognize the color in the big picture at that position, to recognize the green box fast later. And how would it decrease performance, if the white box in the middle is transparent? The question has been asked several times on SO as it seems without a single answer. I found i found a solution at http://werner.yellowcouch.org/Papers/subimg/index.html . Unfortunately its in C++ and i do not understand a thing. Would be nice to have a Java implementation on SO.

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  • Update a PDF to include an encrypted, hidden, unique identifier?

    - by Dave Jarvis
    Background The idea is this: Person provides contact information for online book purchase Book, as a PDF, is marked with a unique hash Person downloads book PDF passwords are annoying and extremely easy to circumvent. The ideal process would be something like: Generate hash based on contact information Store contact information and hash in database Acquire book lock Update an "include" file with hash text Generate book as PDF (using pdflatex) Apply hash to book Release book lock Send email with book download link Technologies The following technologies can be used (other programming languages are possible, but libraries will likely be limited to those supplied by the host): C, Java, PHP LaTeX files PDF files Linux Question What programming techniques (or open source software) should I investigate to: Embed a unique hash (or other mark) to a PDF Create a collusion-attack resistant mark Develop a non-fragile (e.g., PDF -> EPS -> PDF still contains the mark) solution Research I have looked at the following possibilities: Steganography Natural Language Processing (NLP) Convert blank pages in PDF to images; mark those images; reassemble PDF LaTeX watermark package ImageMagick Steganograhy requires keeping a master copy of the images, and I'm not sure if the watermark would survive PDF -> EPS -> PDF, or other types of conversion. LaTeX creates an image cache, so any steganographic process would have to intercept that process somehow. NLP introduces grammatical errors. Inserting blank pages as images is immediately suspect; it is easy to replace suspicious blank pages. The LaTeX watermark package draws visible marks. ImageMagick draws visible marks. What other solutions are possible? Related Links http://www.tcpdf.org/ invisible watermarks in images Thank you!

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