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  • Why is Excel's 'Evaluate' method a general expression evaluator?

    - by jtolle
    A few questions have come up recently involving the Application.Evaluate method callable from Excel VBA. The old XLM macro language also exposes an EVALUATE() function. Both can be quite useful. Does anyone know why the evaluator that is exposed can handle general expressions, though? My own hunch is that Excel needed to give people a way to get ranges from string addresses, and to get the value of named formulas, and just opening a portal to the expression evaluator was the easiest way. (The help for the VBA version does say its purpose it to "convert a Microsoft Excel name to an object or a value".) But of course you don't need the ability to evaluate arbitrary expressions just to do that. (That is, Excel could provide a Name.Evaluate method or something instead.) Application.Evaluate seems kind of...unfinished. It's full behavior isn't very well documented, and there are quite a few quirks and limitations (as described by Charles Williams here: http://www.decisionmodels.com/calcsecretsh.htm) with what is exposed. I suppose the answer could be simply "why not expose it?", but I'd be interested to know what design decisions led to this feature taking the form that it does. Failing that, I'd be interested to hear other hunches.

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  • How to format dates in Jahia 6 CMS?

    - by dpb
    I am helping a friend of mine put up a site for his business. I’ve read different posts and sites trying to find the ideal CMS tool, but people have different views of what is the best, so I finally just picked one of them at random. So I went for an evaluation of Jahia 6.0-CE. As you’ve probably guessed by now, I don’t have so much experience with CMS tools. I just want to setup the CMS, write the templates for the site and let my friend manage the content from there on. So I extracted the sources from SVN and went for a test drive. I managed to create some simple templates to get a hang of things but now I have an issue with a date format. In my definitions.cnd I declared the field like so: date myDateField (datetimepicker[format='dd.MM.yyyy']) This is formatted in the page and the selector also presents this in the dd.MM.yyyy format when inserting the content. But how about sites in other countries, countries that represent the date as MM.dd.yyyy for example? If I specify the format in the CND, hard coded, how can I change this later on so that it adapts based on the browser’s language? Do I extract the content from the repository and format it by hand in the JSP template based on a Locale, or is there a better way? Thank you.

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  • How do I import facebook friends from another website

    - by Jim Zimmerman
    I am looking for a way to connect to facebook by allowing the user to enter in their username and password and have our app connect to their account and get their contacts so that they can invite them to join their group on our site. I have written a facebook app before, but this is not an app as much as it is a connector so that they can invite all their friends or just some to the site we are working on. I have seen several other sites do this and also connect to Yahoo, Gmail and Hotmail contacts. I dont think they are using Facebook Connect to do this since it is so new, but they may be. Any solution in any language is fine as I can port whatever example to use C#. I cannot find anything specifically on Google or Facebook to address this specific problem. Any help is appreciated. I saw a first answer get removed that had suggested i might need to scrape the friends page. The more I look around, this might be what i need to do. Any other way i think will require the person to add it as an app. I am wondering how a answer can get removed, maybe that user deleted it.

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  • Unit Testing Interfaces in Python

    - by Nicholas Mancuso
    I am currently learning python in preperation for a class over the summer and have gotten started by implementing different types of heaps and priority based data structures. I began to write a unit test suite for the project but ran into difficulties into creating a generic unit test that only tests the interface and is oblivious of the actual implementation. I am wondering if it is possible to do something like this.. suite = HeapTestSuite(BinaryHeap()) suite.run() suite = HeapTestSuite(BinomialHeap()) suite.run() What I am currently doing just feels... wrong (multiple inheritance? ACK!).. class TestHeap: def reset_heap(self): self.heap = None def test_insert(self): self.reset_heap() #test that insert doesnt throw an exception... for x in self.inseq: self.heap.insert(x) def test_delete(self): #assert we get the first value we put in self.reset_heap() self.heap.insert(5) self.assertEquals(5, self.heap.delete_min()) #harder test. put in sequence in and check that it comes out right self.reset_heap() for x in self.inseq: self.heap.insert(x) for x in xrange(len(self.inseq)): val = self.heap.delete_min() self.assertEquals(val, x) class BinaryHeapTest(TestHeap, unittest.TestCase): def setUp(self): self.inseq = range(99, -1, -1) self.heap = BinaryHeap() def reset_heap(self): self.heap = BinaryHeap() class BinomialHeapTest(TestHeap, unittest.TestCase): def setUp(self): self.inseq = range(99, -1, -1) self.heap = BinomialHeap() def reset_heap(self): self.heap = BinomialHeap() if __name__ == '__main__': unittest.main()

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  • What's the *right* way to handle a POST in FP?

    - by Malvolio
    I'm just getting started with FP and I'm using Scala, which may not be the best way, since I can always fall back to an imperative style if the going gets tough. I'd just rather not. I've got a very specific question that points to a broader lacuna in my understanding of FP. When a web application is processing a GET request, the user wants information that already exists on the web-site. The application only has to process and format the data in some way. The FB way is clear. When a web application is processing a POST request, the user wants change the information held on the site. True, the information is not typically held in application variables, it's in a database or a flat-file, but still, I get the feeling I'm not grokking FP properly. Is there a pattern for handling updates to static data in an FP language? My vague picture of this is that the application is handed the request and the then-current site state. The application does its thing and returns the new site-state. If the current site-state hasn't changed since the application started, the new state becomes the current state and the reply is sent back to the browser (this is my dim image of Clojure's style); if the current state has been changed (by another thread, well, something else happens ...

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  • Problem in calling a function from different class using protocols-iphone

    - by Muniraj
    I use cocos2d for my game. In which I play a movie and have a separate overlay view for controls.The touches are detected in the overlay view. Now when the touches are detected the function in the game code has to be invoked. But the function is not detected and there is no error. I dont know what has gone wrong. Someone please help me. The code are as follows The protocol part is @protocol Protocol @required -(void) transition1:(id) sender; @end The function which is to be invoked in the game code is (void) transition1:(id) sender { [[Director sharedDirector] replaceScene: [ [Scene node] addChild: [Layer4 node] z:0] ]; } The code in the overlay view in MovieOverlayViewController.h import "Protocol.h" @interface MovieOverlayViewController : UIViewController { UIImageView *overlay; NSObject <Protocol> *transfer; } @end The code in the overlay view in MovieOverlayViewController.m @implementation MovieOverlayViewController (id)init { if ((self = [super init])) self.view = [[[UIView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]] autorelease]; return self; } -(void) viewWillAppear:(BOOL)animated { overlay = [[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"overlay.png"]] autorelease]; [self.view addSubview:overlay]; } (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [touches anyObject]; CGPoint point = [touch locationInView:self.view]; NSLog(@"pointx: %f pointy:%f", point.x, point.y); if (CGRectContainsPoint(CGRectMake(1, 440, 106, 40), point)) { // the function is called here [transfer transition1: nil]; } else if (CGRectContainsPoint(CGRectMake(107, 440, 106, 40), point)) NSLog(@"tab 2 touched"); } (void)dealloc { [overlay release]; [super dealloc]; } @end

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  • Strange thread behavior in Perl

    - by Zaid
    Tom Christiansen's example code (à la perlthrtut) is a recursive, threaded implementation of finding and printing all prime numbers between 3 and 1000. Below is a mildly adapted version of the script #!/usr/bin/perl # adapted from prime-pthread, courtesy of Tom Christiansen use strict; use warnings; use threads; use Thread::Queue; sub check_prime { my ($upstream,$cur_prime) = @_; my $child; my $downstream = Thread::Queue->new; while (my $num = $upstream->dequeue) { next unless ($num % $cur_prime); if ($child) { $downstream->enqueue($num); } else { $child = threads->create(\&check_prime, $downstream, $num); if ($child) { print "This is thread ",$child->tid,". Found prime: $num\n"; } else { warn "Sorry. Ran out of threads.\n"; last; } } } if ($child) { $downstream->enqueue(undef); $child->join; } } my $stream = Thread::Queue->new(3..shift,undef); check_prime($stream,2); When run on my machine (under ActiveState & Win32), the code was capable of spawning only 118 threads (last prime number found: 653) before terminating with a 'Sorry. Ran out of threads' warning. In trying to figure out why I was limited to the number of threads I could create, I replaced the use threads; line with use threads (stack_size => 1);. The resultant code happily dealt with churning out 2000+ threads. Can anyone explain this behavior?

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  • Where should I put validation code?

    - by D Lawson
    I'm creating interfaces and abstract classes that represent a messaging framework for short text-based messages like SMS, email, twitter, xml, etc.. and I was wondering where I should put the message validation code. The thing is that I am only writing the superclasses and interfaces, so I'm not putting the actual implementation in, I'll just put the hooks in that allow others to validate the content of the messages. The way I see it, I could do it several ways: in the abstract superclass "Message", have an abstract method 'isValid'. A variation on this would be to have isValid be called when the Message constructor is called, throwing a MalformedMessageException if the message is formatted incorrectly. in the transport layer, immediately before sending, validate the message. I would have a send(Message) method that calls an isValid(Message) method immediately before it sends. have a singleton message validator with a static method isValid(Message) that is called at some point. I'm sure there are other options that I'm missing. Currently, I'm leaning towards the first one, but it doesn't feel right to me to have validation code in what should be a domain object.

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  • Singleton issue causing a buffer overrun

    - by Rudiger
    Hi everyone, Ive created a singleton to store 2 arrays: @interface Globals : NSObject { NSMutableArray *items; NSMutableArray *extras; } + (Globals *)sharedInstance; @property (nonatomic, assign) NSMutableArray *items; @property (nonatomic, assign) NSMutableArray *extras; @end @implementation Globals @synthesize items, extras; + (Globals *)sharedInstance { static Globals *myInstance = nil; @synchronized(self) { if(!myInstance) { myInstance = [[Globals alloc] init]; } } return myInstance; } -(void)dealloc { [items release]; [extras release]; [super dealloc]; } @end When I set the Arrays in the singleton from the App delegate and then output them to NSLog it displays what is expected. But when I call it from a view controller further into the App it displays the first entry fine, some of the second entry and then garbage which is i assume a buffer overrun, sometimes it also crashes. I set the singleton array in the appDelegate like so: Globals *sharedInstance = [Globals sharedInstance]; [sharedInstance setItems:items]; and retrieve it: [[[sharedInstance items] objectAtIndex:indexPath.row] objectForKey:@"name"]; cell.description.text = [[[sharedInstance items] objectAtIndex:indexPath.row] objectForKey:@"description"]; Name works fine in both cells if there is 2, description works in the first case, never in the second case. Is it because the arrays in my singleton aren't static? If so why is it outputting the first entry fine? Cheers for any help.

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  • VB app to web service

    - by brandon
    I know very little about web service but I assumed it would be the solution I was looking for. Basically I made an application in VB that I want to be ubiquitous for a lack of a better word. I need it to receive requests from multiple users and respond all at once. I was told "technically if you write a webservice you can provide as many results back to users as are connected." Maybe there is another solution for me that will give me the results I want. Here is an example of what I'm trying to do. Lets say I make an application in VB that does math. I now make a website. My website allows for a person to input 1 + 1 they click submit and my website then connects to my VB application running on my server listening for a request. It accepts the request from my website, and then it solves the math problem and returns the answer back to the website "1 + 1 = 2" That is only an example of the type of thing I need. My problem is that I can't have multiple people visiting my website all connecting to that same application running on my server so somehow I need the application to be where it can be accessed by multiple users. I was told a web service would be the answer but if there is another solution I'd like to know. If the only solution is a web service, then how can I manage to either convert the VB app to a web service? Can I have to convert the app to asp.net or some other language? Is there an easier option?

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  • Do the 'up to date' guarantees provided by final field in Java's memory model extend to indirect ref

    - by mattbh
    The Java language spec defines semantics of final fields in section 17.5: The usage model for final fields is a simple one. Set the final fields for an object in that object's constructor. Do not write a reference to the object being constructed in a place where another thread can see it before the object's constructor is finished. If this is followed, then when the object is seen by another thread, that thread will always see the correctly constructed version of that object's final fields. It will also see versions of any object or array referenced by those final fields that are at least as up-to-date as the final fields are. My question is - does the 'up-to-date' guarantee extend to the contents of nested arrays, and nested objects? An example scenario: Thread A constructs a HashMap of ArrayLists, then assigns the HashMap to final field 'myFinal' in an instance of class 'MyClass' Thread B sees a (non-synchronized) reference to the MyClass instance and reads 'myFinal', and accesses and reads the contents of one of the ArrayLists In this scenario, are the members of the ArrayList as seen by Thread B guaranteed to be at least as up to date as they were when MyClass's constructor completed?

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  • Problem FlashVars parameter asp.net

    - by sofie-vo
    Code for asp.net page <%@ Page Language="VB" AutoEventWireup="false" CodeFile="trainingupload.aspx.vb" Inherits="trainingupload" %> <!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> </head> <body> <form id="form1" runat="server"> <div height> <object width="1000" height="800"> <param name="movie" value="player.swf" /> <param name="FlashVars" value='userid=<%=String.Format(getuser())%>" '/> <embed src="bin-release/trainingscentrum.swf" FlashVars='userid=<%=String.Format(getuser())%>" ' width="1500" height="800" /> </embed> </object> </div> </form> </body> </html> Code behind Public Function getuser() As Guid Dim user As MembershipUser = Membership.GetUser() Dim userid As Guid = (CType(user.ProviderUserKey, Guid)) Return userid End Function In the code above I use an function to return the userid. When I replace <%=String.Format(getuser())% with an actual userid, I get the value in my flex application. But this code returns nothing. What am I doing wrong?

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  • Send string from java (or other platform) to application

    - by MrSnowflake
    I want to send a barcode, read with my cellphone, to my computer. My computer has a simple server running, which listens to barcodes. When a barcode arrives, the server app should be able to input the value of the received barcode into the active application (I don't really care which application is going to get the input, the user should be able to select gedit, a terminal window or the browser if they choose to). My language at the moment is Java on GNU/Linux (Ubuntu), so I know about the Robot class. But the Robot class emulates a keyboard, which means: when you send VK_1 on a US keyboard layout, the output is '1' indeed, but when you send VK_1 on another layout (like belgian, which I use), which requires shift for the '1' key, the output is '&' (this is the character on the '1' key, when you don't hold shift). I also found xsendkeys, but this application too requires you to specify whether you need to hold shift. So it will be able to send an 'a' but for an 'A' (thus capital) you need to specify you want to hold shift with your 'a'. Isn't there an easy way to do this, for GNU/Linux and Windows, just using strings. I want to be able to send "12a68dd" to the active application. And I also would like to be able to send UTF-8 characters to the active application. I have been looking for a solution, but most require the breakdown in multiple keystrokes, which are often dependent on the keyboard layout.

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  • dynamically insert new rows in the table (JavaScript) ?

    - by Karandeep Singh
    <script type="text/javascript" language="javascript"> function addNewRow() { var table = document.getElementById("table1"); var tr = table.insertRow(); var td = tr.insertCell(); td.innerHTML= "a"; td = tr.insertCell(); td.innerHTML= "b"; td = tr.insertCell(); td.innerHTML= "c"; td = tr.insertCell(); td.innerHTML= "d"; td = tr.insertCell(); td.innerHTML= "e"; } </script> <body> <table id="table1" border="1" cellpadding="0" cellspacing="0" width="100%"> <tr id="row1"> <td>1</td> <td>2</td> <td>3</td> <td>4</td> <td>5</td> </tr> </table> <input type="button" onClick="addNewRow()" value="Add New"/> </body> This example is for dynamically insert new row and cells in the table. But its behavior is different in all browsers. Internet Explorer = It add row in the last and new added cells are starts from first. Chrome/Safari = It add new row in the first and new added cells are starts from end. Mozilla Firefox = It is not working. Sir, I want new added row in the last and new added cells starts from first like(Interner Explorer) in all browsers. If you have any solution for same behavior please tell me. Thanks,

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  • Number of characters recommended for a statement

    - by liaK
    Hi, I have been using Qt 4.5 and so do C++. I have been told that it's a standard practice to maintain the length of each statement in the application to 80 characters. Even in Qt creator we can make a right border visible so that we can know whether we are crossing the 80 characters limit. But my question is, Is it really a standard being followed? Because in my application, I use indenting and all, so it's quite common that I cross the boundary. Other cases include, there might be a error statement which will be a bit explanatory one and which is in an inner block of code, so it too will cross the boundary. Usually my variable names look bit lengthier so as to make the names meaningful. When I call the functions of the variable names, again I will cross. Function names will not be in fewer characters either. I agree a horizontal scroll bar shows up and it's quite annoying to move back and forth. So, for function calls including multiple arguments, when the boundary is reached I will make the forth coming arguments in the new line. But besides that, for a single statement (for e.g a very long error message which is in double quotes " " or like longfun1()->longfun2()->...) if I use an \ and split into multiple lines, the readability becomes very poor. So is it a good practice to have those statement length restrictions? If this restriction in statement has to be followed? I don't think it depends on a specific language anyway. I added C++ and Qt tags since if it might. Any pointers regarding this are welcome.

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  • How to resize a UISwitch?

    - by mshsayem
    I have made a custom UISwitch (from this post). But the problem is, my custom texts are a bit long. Is there any way to resize the switch? [I tried setBounds, did not work] Edit: Here is the code I used: @interface CustomUISwitch : UISwitch - (void) setLeftLabelText: (NSString *) labelText; - (void) setRightLabelText: (NSString *) labelText; @end @implementation CustomUISwitch - (UIView *) slider { return [[self subviews] lastObject]; } - (UIView *) textHolder { return [[[self slider] subviews] objectAtIndex:2]; } - (UILabel *) leftLabel { return [[[self textHolder] subviews] objectAtIndex:0]; } - (UILabel *) rightLabel { return [[[self textHolder] subviews] objectAtIndex:1]; } - (void) setLeftLabelText: (NSString *) labelText { [[self leftLabel] setText:labelText]; } - (void) setRightLabelText: (NSString *) labelText { [[self rightLabel] setText:labelText]; } @end mySwitch = [[CustomUISwitch alloc] initWithFrame:CGRectZero]; //Tried these, but did not work //CGRect aFrame = mySwitch.frame; //aFrame.size.width = 200; //aFrame.size.height = 100; //mySwitch.frame = aFrame; [mySwitch setLeftLabelText: @"longValue1"]; [mySwitch setRightLabelText: @"longValue2"];

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  • Trouble with go tour crawler exercise

    - by David Mason
    I'm going through the go tour and I feel like I have a pretty good understanding of the language except for concurrency. On slide 71 there is an exercise that asks the reader to parallelize a web crawler (and to make it not cover repeats but I haven't gotten there yet.) Here is what I have so far: func Crawl(url string, depth int, fetcher Fetcher, ch chan string) { if depth <= 0 { return } body, urls, err := fetcher.Fetch(url) if err != nil { ch <- fmt.Sprintln(err) return } ch <- fmt.Sprintf("found: %s %q\n", url, body) for _, u := range urls { go Crawl(u, depth-1, fetcher, ch) } } func main() { ch := make(chan string, 100) go Crawl("http://golang.org/", 4, fetcher, ch) for i := range ch { fmt.Println(i) } } The issue I have is where to put the close(ch) call. If I put a defer close(ch) somewhere in the Crawl method, then I end up writing to a closed channel in one of the spawned goroutines, since the method will finish execution before the spawned goroutines do. If I omit the call to close(ch), as is shown in my example code, the program deadlocks after all the goroutines finish executing but the main thread is still waiting on the channel in the for loop since the channel was never closed.

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  • Javascript not reading value from hidden textBox - JQuery C#

    - by Paul van Valkenburgh
    I'm a non-specialist with JavaScript / JQuery and I'm having trouble figuring out why my script doesn't work. When my C# page loads, I have a hidden textBox txtHiddenKeywordArray which gets dynamically filled with comma separated values like... horse, buggy, track I'm trying to use the highlight functionality in jquery.highlight-3.js where I have a label text field that will contain and highlight the words in the keywords list. I'm using the script <script language="javascript" type="text/javascript"> var myString = document.getElementById('<%=txtHiddenKeywordArray.ClientID%>').val() myArray = myString.split(" "); $(document).ready(function () { for (i = 0; i < myArray.length; i++) $("p").highlight(myArray[i]) }); </script> Here is the textBox declaration : <asp:TextBox ID="txtHiddenKeywordArray" ClientIDMode="Static" runat="server" Visible="false"></asp:TextBox> It worked great when I hard coded the values of var myString. I've tried researching it and keep seeing the same example of the way I have it done. The page does use a MasterPage. Could this affect it? Any idea how I can get the script to see the values from the textbox? Do I need a RegisterStartUpScript or something? Thanks for any help you can provide.

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  • Why is T() = T() allowed?

    - by Rimo
    I believe the expression T() creates an rvalue (by the Standard). However, the following code compiles (at least on gcc4.0): class T {}; int main() { T() = T(); } I know technically this is possible because member functions can be invoked on temporaries and the above is just invoking the operator= on the rvalue temporary created from the first T(). But conceptually this is like assigning a new value to an rvalue. Is there a good reason why this is allowed? Edit: The reason I find this odd is it's strictly forbidden on built-in types yet allowed on user-defined types. For example, int(2) = int(3) won't compile because that is an "invalid lvalue in assignment". So I guess the real question is, was this somewhat inconsistent behavior built into the language for a reason? Or is it there for some historical reason? (E.g it would be conceptually more sound to allow only const member functions to be invoked on rvalue expressions, but that cannot be done because that might break some existing code.)

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  • Purpose of singletons in programming

    - by thecoshman
    This is admittedly a rather loose question. My current understanding of singletons is that they are a class that you set up in such a way that only one instance is ever created. This sounds a lot like a static class to me. The main differnce being that with a static class you don't / can't instance it, you just use it such as Math.pi(). With a singletong class, you would still need to do something like singleton mySingleton = new singleton(); mysingleton.set_name("foo"); singleton otherSingleton = new singleton(); // correct me if i am wrong, but mysingleton == othersingleton right now, yes? // this the following should happen? otherSingleston.set_name("bar"); mysingleton.report_name(); // will output "bar" won't it? Please note, I am asking this language independently, more about the concept. So I am not so worried about actually how to coed such a class, but more why you would wan't to and what thing you would need to consider.

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  • Can I do something like this?

    - by kumar
    <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<IEnumerable<StudentInfo>>" %> <% int i = 0; %> <% foreach(var e in Model){%> <div> <% if(i==0) { %> <% Html.RenderAction("student", "home", new { @et = e}); %> <% break; } %> <div> <span> <% Html.RenderAction("studentDetails", "home", new { @et = e }); %> </span> </div> </div> <%i++; } %> here my intension was to execute Renderction Student only once.. and Studentdetails should be multiple times.. but int value is allways taking i =0 bec each time page is loading its considering 0 allways.. can anybody tell me how to do this? thanks

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  • How can I make this simple C# generics factory work?

    - by Kevin Brassen
    I have this design: public interface IFactory<T> { T Create(); T CreateWithSensibleDefaults(); } public class AppleFactory : IFactory<Apple> { ... } public class BananaFactory : IFactory<Banana> { ... } // ... The fictitious Apple and Banana here do not necessarily share any common types (other than object, of course). I don't want clients to have to depend on specific factories, so instead, you can just ask a FactoryManager for a new type. It has a FactoryForType method: IFactory<T> FactoryForType<T>(); Now you can invoke the appropriate interface methods with something like FactoryForType<Apple>().Create(). So far, so good. But there's a problem at the implementation level: how do I store this mapping from types to IFactory<T>s? The naive answer is an IDictionary<Type, IFactory<T>>, but that doesn't work since there's no type covariance on the T (I'm using C# 3.5). Am I just stuck with an IDictionary<Type, object> and doing the casting manually?

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  • How can I implement a splay tree that performs the zig operation last, not first?

    - by Jakob
    For my Algorithms & Data Structures class, I've been tasked with implementing a splay tree in Haskell. My algorithm for the splay operation is as follows: If the node to be splayed is the root, the unaltered tree is returned. If the node to be splayed is one level from the root, a zig operation is performed and the resulting tree is returned. If the node to be splayed is two or more levels from the root, a zig-zig or zig-zag operation is performed on the result of splaying the subtree starting at that node, and the resulting tree is returned. This is valid according to my teacher. However, the Wikipedia description of a splay tree says the zig step "will be done only as the last step in a splay operation" whereas in my algorithm it is the first step in a splay operation. I want to implement a splay tree that performs the zig operation last instead of first, but I'm not sure how it would best be done. It seems to me that such an algorithm would become more complex, seeing as how one needs to find the node to be splayed before it can be determined whether a zig operation should be performed or not. How can I implement this in Haskell (or some other functional language)?

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  • Help me find article on Multi-threading and Event Handling in Java

    - by JDR
    I once read an article on how to properly write event handlers for multi-threading in Java, but I can't for the life of me find it anymore. It described the pitfalls and potentials for deadlocks that can occur when firing events (not Swing events mind you, but general events like model update notifications). To clarify, the situation would be as such: // let's say this is code from an MVC model somewhere public void setSomeProperty(String myProperty){ if(!this.myProperty.equals(myProperty)){ this.myProperty = myProperty; fireMyPropertyChangedEvent(...); } } The article described how passing control to arbitrary external listener code was a potential cause for deadlock. I now find myself in a situation where I need to fire such events in a multithreaded environment and I would very much like to read the article again to see what it has to say before I continue. Does anyone know the article I'm referring to? I believe it came as a (fairly short) PDF. It started off with an initial naive implementation and incrementally pointed out flaws and improved upon it. It ended with a sort of final proper-way-to-fire-multithreaded-events. I've searched endlessly in my browse history and on google, but all I could find were endless amounts topics on Swing event dispatch threads. Thank you.

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  • creating an object within a function of a program

    - by user1066524
    could someone please tell me what I need to do in order to create an object in a function. I will try to explain by making up some sort of example... Let's say I have a program named TimeScheduler.cpp that implements the class Schedule.h (and I have the implementation in a separate file Schedule.cpp where we define the methods). In the declaration file we have declared two constructors Schedule(); //the default and Schedule(int, int, int);//accepts three arguments to get to the point--let's say in the main program file TimeScheduler.cpp we created our own functions in this program apart from the functions inherited from the class Schedule. so we have our prototypes listed at the top. /*prototypes*/ void makeSomeTime(); etc..... we have main(){ //etc etc... } we then define these program functions void makeSomeTime(){ //process } let's say that inside the function makeSomeTime(), we would like to create an array of Schedule objects like this Schedule ob[]={ summer(5,14, 49), fall(9,25,50) }; what do I have to do to the function makeSomeTime() in order for it to allow me to create this array of objects. The reason I ask is currently i'm having difficulty with my own program in that it WILL allow me to create this array of objects in main()....but NOT in a function like I just gave an example of. The strange thing is it will allow me to create a dynamic array of objects in the function..... like Schedule *ob = new Schedule[n+1]; ob[2]= Schedule(x,y,z); Why would it let me assign to a non-dynamic array in main(), but not let me do that in the function?

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