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  • Ruby on Rails: How to use a local variable in a collection_select

    - by mmacaulay
    I have a partial view which I'm passing a local variable into: <%= render :partial => "products/product_row", :locals => { :product => product } %> These are rows in a table, and I want to have a <select> in each row for product categories: <%= collection_select(:product, :category_id, @current_user.categories, :id, :name, options = {:prompt => "-- Select a category --"}, html_options = { :id => "", :class => "product_category" }) %> (Note: the id = "" is there because collection_select tries to give all these select elements the same id.) The problem is that I want to have product.category be selected by default and this doesn't work unless I have an instance variable @product. I can't do this in the controller because this is a collection of products. One way I was able to get around this was to have this line just before the collection_select: <% @product = product %> But this seems very hacky and would be a problem if I ever wanted to have an actual instance variable @product in the controller. I guess one workaround would be to name this instance variable something more specific like @product_select_tmp in hopes of not interfering with anything that might be declared in the controller. This still seems very hacky though, and I'd prefer a cleaner solution. Surely there must be a way to have collection_select use a local variable instead of an instance variable. Note that I've tried a few different ways of calling collection_select with no success: <%= collection_select(product, ... <%= collection_select('product', ... etc. Any help greatly appreciated!

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  • Open the Word Application from a button on a web page

    - by Andrea
    I'm developing a proof of concept web application: A web page with a button that opens the Word Application installed on the user's PC. I'm stuck with a C# project in Visual Studio 2008 Express (Windows XP client, LAMP server). I've followed the Writing an ActiveX Control in .NET tutorial and after some tuning it worked fine. Then I added my button for opening Word. The problem is that I can reference the Microsoft.Office.Interop.Word from the project, but I'm not able to access it from the web page. The error says "That assembly does not allow partially trusted callers". I've read a lot about security in .NET, but I'm totally lost now. Disclaimer: I'm into .NET since 4 days ago. I've tried to work around this issue but I cannot see the light!! I don't even know if it will ever be possible! using System; using System.Collections.Generic; using System.ComponentModel; using System.Drawing; using System.Data; using System.Linq; using System.Text; using System.Windows.Forms; using Word = Microsoft.Office.Interop.Word; using System.IO; using System.Security.Permissions; using System.Security; [assembly: AllowPartiallyTrustedCallers] namespace OfficeAutomation { public partial class UserControl1 : UserControl { public UserControl1() { InitializeComponent(); } private void openWord_Click(object sender, EventArgs e) { try { Word.Application Word_App = null; Word_App = new Word.Application(); Word_App.Visible = true; } catch (Exception exc) { MessageBox.Show("Can't open Word application (" + exc.ToString() + ")"); } } } }

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  • Checking for empty arrays: count vs empty

    - by Dan McG
    This question on 'How to tell if a PHP array is empty' had me thinking of this question Is there a reason that count should be used instead of empty when determining if an array is empty or not? My personal thought would be if the 2 are equivalent for the case of empty arrays you should use empty because it gives a boolean answer to a boolean question. From the question linked above, it seems that count($var) == 0 is the popular method. To me, while technically correct, makes no sense. E.g. Q: $var, are you empty? A: 7. Hmmm... Is there a reason I should use count == 0 instead or just a matter of personal taste? As pointed out by others in comments for a now deleted answer, count will have performance impacts for large arrays because it will have to count all elements, whereas empty can stop as soon as it knows it isn't empty. So, if they give the same results in this case, but count is potentially inefficient, why would we ever use count($var) == 0?

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  • bad_alloc occuring when allocating small structs

    - by SalamiArmi
    A bad_alloc has started showing up in some code which looks perfectly valid to me and has worked very well in the past. The bad alloc only occurs once every 50-3000 iterations of the code, which is also confusing. The code itself is from a singly linked list, simply adding a new element to the queue: template<typename T> struct container { inline container() : next(0) {} container *next; T data; }; void push(const T &data) { container<T> *newQueueMember = new container<T>; //... unrelated to crash } Where T is: struct test { int m[256]; }; Changing the size of the array allocated array to anything but very small values (1-8 ints) still results in a bad_alloc occasionally. A few extra notes about my program: - I used Poco::ThreadPool to thread my program. I've only recently added this functionality, before I had it running with Win32 threads. However, only the main thread ever calls push(). - I am also occasionally getting other crashes which could be related. However, when I try to debug with visual studio 2008, I can't navigate back to the call stack, or the crash happens deep within new(). Thanks in advance.

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  • Using OUTPUT/INTO within instead of insert trigger invalidates 'inserted' table

    - by Dan
    I have a problem using a table with an instead of insert trigger. The table I created contains an identity column. I need to use an instead of insert trigger on this table. I also need to see the value of the newly inserted identity from within my trigger which requires the use of OUTPUT/INTO within the trigger. The problem is then that clients that perform INSERTs cannot see the inserted values. For example, I create a simple table: CREATE TABLE [MyTable]( [MyID] [int] IDENTITY(1,1) NOT NULL, [MyBit] [bit] NOT NULL, CONSTRAINT [PK_MyTable_MyID] PRIMARY KEY NONCLUSTERED ( [MyID] ASC )) Next I create a simple instead of trigger: create trigger [trMyTableInsert] on [MyTable] instead of insert as BEGIN DECLARE @InsertedRows table( MyID int, MyBit bit); INSERT INTO [MyTable] ([MyBit]) OUTPUT inserted.MyID, inserted.MyBit INTO @InsertedRows SELECT inserted.MyBit FROM inserted; -- LOGIC NOT SHOWN HERE THAT USES @InsertedRows END; Lastly, I attempt to perform an insert and retrieve the inserted values: DECLARE @tbl TABLE (myID INT) insert into MyTable (MyBit) OUTPUT inserted.MyID INTO @tbl VALUES (1) SELECT * from @tbl The issue is all I ever get back is zero. I can see the row was correctly inserted into the table. I also know that if I remove the OUTPUT/INTO from within the trigger this problem goes away. Any thoughts as to what I'm doing wrong? Or is how I want to do things not feasible? Thanks.

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  • Using ControllerClassNameHandlerMapping with @Controller and extending AbstractController

    - by whiskerz
    Hey there, actually I thought I was trying something really simple. ControllerClassNameHandlerMapping sounded great to produce a small spring webapp using a very lean configuration. Just annotate the Controller with @Controller, have it extend AbstractController and the configuration shouldn't need more than this <context:component-scan base-package="test.mypackage.controller" /> <bean id="urlMapping" class="org.springframework.web.servlet.mvc.support.ControllerClassNameHandlerMapping" /> to resolve my requests and map them to my controllers. I've mapped the servlet to "*.spring", and calling <approot>/hello.spring All I ever get is an error stating that no mapping was found. If however I extend the MultiActionController, and do something like <approot>/hello/hello.spring it works. Which somehow irritates me, as I would have thought that if that is working, why didn't my first try? Does anyone have any idea? The two controllers I used looked like this @Controller public class HelloController extends AbstractController { @Override protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response) throws Exception { ModelAndView modelAndView = new ModelAndView("hello"); modelAndView.addObject("message", "Hello World!"); return modelAndView; } } and @Controller public class HelloController extends MultiActionController { public ModelAndView hello(HttpServletRequest request, HttpServletResponse response) throws Exception { ModelAndView modelAndView = new ModelAndView("hello"); modelAndView.addObject("message", "Hello World!"); return modelAndView; } }

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  • Use of Syntactic Sugar / Built in Functionality

    - by Kyle Rozendo
    I was busy looking deeper into things like multi-threading and deadlocking etc. The book is aimed at both pseudo-code and C code and I was busy looking at implementations for things such as Mutex locks and Monitors. This brought to mind the following; in C# and in fact .NET we have a lot of syntactic sugar for doing things. For instance (.NET 3.5): lock(obj) { body } Is identical to: var temp = obj; Monitor.Enter(temp); try { body } finally { Monitor.Exit(temp); } There are other examples of course, such as the using() {} construct etc. My question is when is it more applicable to "go it alone" and literally code things oneself than to use the "syntactic sugar" in the language? Should one ever use their own ways rather than those of people who are more experienced in the language you're coding in? I recall having to not use a Process object in a using block to help with some multi-threaded issues and infinite looping before. I still feel dirty for not having the using construct in there. Thanks, Kyle

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  • Please help us non-C++ developers understand what RAII is

    - by Charlie Flowers
    Another question I thought for sure would have been asked before, but I don't see it in the "Related Questions" list. Could you C++ developers please give us a good description of what RAII is, why it is important, and whether or not it might have any relevance to other languages? I do know a little bit. I believe it stands for "Resource Acquisition is Initialization". However, that name doesn't jive with my (possibly incorrect) understanding of what RAII is: I get the impression that RAII is a way of initializing objects on the stack such that, when those variables go out of scope, the destructors will automatically be called causing the resources to be cleaned up. So why isn't that called "using the stack to trigger cleanup" (UTSTTC:)? How do you get from there to "RAII"? And how can you make something on the stack that will cause the cleanup of something that lives on the heap? Also, are there cases where you can't use RAII? Do you ever find yourself wishing for garbage collection? At least a garbage collector you could use for some objects while letting others be managed? Thanks.

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  • Python and a "time value of money" problem.

    - by jamieb
    (I asked this question earlier today, but I did a poor job of explaining myself. Let me try again) I have a client who is an industrial maintenance company. They sell service agreements that are prepaid 20 hour blocks of a technician's time. Some of their larger customers might burn through that agreement in two weeks while customers with fewer problems might go eight months on that same contract. I would like to use Python to help model projected sales revenue and determine how many billable hours per month that they'll be on the hook for. If each customer only ever bought a single service contract (never renewed) it would be easy to figure sales as monthly_revenue = contract_value * qty_contracts_sold. Billable hours would also be easy: billable_hrs = hrs_per_contract * qty_contracts_sold. However, how do I account for renewals? Assuming that 90% (or some other arbitrary amount) of customers renew, then their monthly revenue ought to grow geometrically. Another important variable is how long the average customer burns through a contract. How do I determine what the revenue and billable hours will be 3, 6, or 12 months from now, based on various renewal and burn rates? I assume that I'd use some type of recursive function but math was never one of my strong points. Any suggestions please? Edit: I'm thinking that the best way to approach this is to think of it as a "time value of money" problem. I've retitled the question as such. The problem is probably a lot more common if you think of "monthly sales" as something similar to annuity payments.

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  • Doubts about .NET Garbage Collector

    - by Smjert
    I've read some docs about the .NET Garbage Collector but i still have some doubts (examples in C#): 1)Does GC.Collect() call a partial or a full collection? 2)Does a partial collection block the execution of the "victim" application? If yes.. then i suppose this is a very "light" things to do since i'm running a game server that uses 2-3GB of memory and i "never" have execution stops (or i can't see them..). 3)I've read about GC roots but still can't understand how exactly they works. Suppose that this is the code (C#): MyClass1: [...] public List<MyClass2> classList = new List<MyClass2>(); [...] Main: main() { MyClass1 a = new MyClass1(); MyClass2 b = new MyClass2(); a.classList.Add(b); b = null; DoSomeLongWork(); } Will b ever be eligible to be garbage collected(before the DoSomeLongWork finishes)? The reference to b that classList contains, can it be considered a root? Or a root is only the first reference to the instance? (i mean, b is the root reference because the instantiation happens there).

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  • Is it safe to use random Unicode for complex delimiter sequences in strings?

    - by ccomet
    Question: In terms of program stability and ensuring that the system will actually operate, how safe is it to use chars like ¦, § or ‡ for complex delimiter sequences in strings? Can I reliable believe that I won't run into any issues in a program reading these incorrectly? I am working in a system, using C# code, in which I have to store a fairly complex set of information within a single string. The readability of this string is only necessary on the computer side, end-users should only ever see the information after it has been parsed by the appropriate methods. Because some of the data in these strings will be collections of variable size, I use different delimiters to identify what parts of the string correspond to a certain tier of organization. There are enough cases that the standard sets of ;, |, and similar ilk have been exhausted. I considered two-char delimiters, like ;# or ;|, but I felt that it would be very inefficient. There probably isn't that large of a performance difference in storing with one char versus two chars, but when I have the option of picking the smaller option, it just feels wrong to pick the larger one. So finally, I considered using the set of characters like the double dagger and section. They only take up one char, and they are definitely not going to show up in the actual text that I'll be storing, so they won't be confused for anything. But character encoding is finicky. While the visibility to the end user is meaningless (since they, in fact, won't see it), I became recently concerned about how the programs in the system will read it. The string is stored in one database, while a separate program is responsible for both encoding and decoding the string into different object types for the rest of the application to work with. And if something is expected to be written one way, is possibly written another, then maybe the whole system will fail and I can't really let that happen. So is it safe to use these kind of chars for background delimiters?

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  • Save Jquery Object without losing its binding

    - by Ahmad Satiri
    Hi I have object created using jquery where each object has it's own binding. function closeButton(oAny){ var div = create_div(); $(div).attr("id","btn_"+$(oAny).attr("id")); var my_parent = this; $(div).html("<img src='"+ my_parent._base_url +"/assets/images/close.gif'>"); $(div).click(function(){ alert("do some action here"); }); return div; } var MyObject = WindowObject(); var btn = closeButton(MyObject); $(myobject).append(btn); $("body").append(myobject); //at this point button will work as i expected //save to array for future use ObjectCollections[0] = myobject; //remove $(myobject).remove(); $(body).append(ObjectCollections[0]); // at this point button will not work For the first time i can show my object and close button is working as i expected. But if i save myobject to any variable for future use. It will loose its binding. Anybody ever try to do this ? Is there any work around ? or It is definitely a bad idea ? .And thanks for answering my question.

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  • Passing IDisposable objects through constructor chains

    - by Matt Enright
    I've got a small hierarchy of objects that in general gets constructed from data in a Stream, but for some particular subclasses, can be synthesized from a simpler argument list. In chaining the constructors from the subclasses, I'm running into an issue with ensuring the disposal of the synthesized stream that the base class constructor needs. Its not escaped me that the use of IDisposable objects this way is possibly just dirty pool (plz advise?) for reasons I've not considered, but, this issue aside, it seems fairly straightforward (and good encapsulation). Codes: abstract class Node { protected Node (Stream raw) { // calculate/generate some base class properties } } class FilesystemNode : Node { public FilesystemNode (FileStream fs) : base (fs) { // all good here; disposing of fs not our responsibility } } class CompositeNode : Node { public CompositeNode (IEnumerable some_stuff) : base (GenerateRaw (some_stuff)) { // rogue stream from GenerateRaw now loose in the wild! } static Stream GenerateRaw (IEnumerable some_stuff) { var content = new MemoryStream (); // molest elements of some_stuff into proper format, write to stream content.Seek (0, SeekOrigin.Begin); return content; } } I realize that not disposing of a MemoryStream is not exactly a world-stopping case of bad CLR citizenship, but it still gives me the heebie-jeebies (not to mention that I may not always be using a MemoryStream for other subtypes). It's not in scope, so I can't explicitly Dispose () it later in the constructor, and adding a using statement in GenerateRaw () is self-defeating since I need the stream returned. Is there a better way to do this? Preemptive strikes: yes, the properties calculated in the Node constructor should be part of the base class, and should not be calculated by (or accessible in) the subclasses I won't require that a stream be passed into CompositeNode (its format should be irrelevant to the caller) The previous iteration had the value calculation in the base class as a separate protected method, which I then just called at the end of each subtype constructor, moved the body of GenerateRaw () into a using statement in the body of the CompositeNode constructor. But the repetition of requiring that call for each constructor and not being able to guarantee that it be run for every subtype ever (a Node is not a Node, semantically, without these properties initialized) gave me heebie-jeebies far worse than the (potential) resource leak here does.

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  • gethostbyname fails for local hostname after resuming from hibernate (Vista+7?)

    - by John
    Just wondering if anyone else has spotted this: On some user's machines running our software, occasionally the call to Win32 winsock gethostbyname fails with error code 11004. For the argument to gethostbyname, I'm passing in the result from gethostname. Now the docs say 11004 is WSANO_DATA. None of the descriptions seem to be relevant (it occurs if you pass in an IP6 address, but as I say, I'm passing in a hostname). Even more interesting is that the MSDN suggests that this combination (gethostname followed by gethostbyname) should never fail, not even if there is no IP address (in that case it would just return empty list of IPs). Here is the quote from the gethostname MSDN entry: ...it is guaranteed that the name returned will be successfully parsed by gethostbyname and WSAAsyncGetHostByName. It only ever happens after resuming from hibernate, in that short period when the network is restarting, and only on Vista/7 (well I've only seen it on Vista and 7). One theory I had was that it related to IP6. Maybe for a short period the network reports an IP6 address but not the corresponging IP4 address (I'm pretty sure that all the client machines are dual IP stack, but I could be wrong). I tried to reproduce by turning off my network card (to force no IP addresses) and couldn't reproduce. Anyone seen this before? Any ideas? John

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  • Am I using handlers in the wrong way?

    - by superexsl
    Hey, I've never used HTTP Handlers before, and I've got one working, but I'm not sure if I'm actually using it properly. I have generated a string which will be saved as a CSV file. When the user clicks a button, I want the download dialog box to open so that the user can save the file. What I have works, but I keep reading about modifying the web.config file and I haven't had to do that. My Handler: private string _data; private string _title = "temp"; public void AddData(string data) { _data = data; } public bool IsReusable { get { return false; } } public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/csv"; context.Response.AddHeader("content-disposition", "filename=" + _title + ".csv"); context.Response.Write(_data); context.Response.Flush(); context.Response.Close(); } And this is from the page that allows the user to download: (on button click) string dataToConvert = "MYCSVDATA...."; csvHandler handler = new csvHandler(); handler.AddData(dataToConvert); handler.ProcessRequest(this.Context); This works fine, but no examples I've seen ever instantiate the handler and always seem to modify the web.config. Am I doing something wrong? Thanks

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  • 500 Worker Threads, what kind of thread pool?

    - by Submerged
    I am wondering if this is the best way to do this. I have about 500 threads that run indefinitely, but Thread.sleep for a minute when done one cycle of processing. ExecutorService es = Executors.newFixedThreadPool(list.size()+1); for (int i = 0; i < list.size(); i++) { es.execute(coreAppVector.elementAt(i)); //coreAppVector is a vector of extends thread objects } The code that is executing is really simple and basically just this class aThread extends Thread { public void run(){ while(true){ Thread.sleep(ONE_MINUTE); //Lots of computation every minute } } } I do need a separate threads for each running task, so changing the architecture isn't an option. I tried making my threadPool size equal to Runtime.getRuntime().availableProcessors() which attempted to run all 500 threads, but only let 8 (4xhyperthreading) of them execute. The other threads wouldn't surrender and let other threads have their turn. I tried putting in a wait() and notify(), but still no luck. If anyone has a simple example or some tips, I would be grateful! Well, the design is arguably flawed. The threads implement Genetic-Programming or GP, a type of learning algorithm. Each thread analyzes advanced trends makes predictions. If the thread ever completes, the learning is lost. That said, I was hoping that sleep() would allow me to share some of the resources while one thread isn't "learning"

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  • CSS Background image in Redmine template arbitrarily not loading

    - by Pekka
    I`m in the process of building a template for Redmine (a project management system based on Ruby on Rails.) Ruby is running on a virtual server from a Bitnami.org installation package. The OS is Windows. The template essentially consists of a styles.css file. In that file, I have the following line: #header { padding: 0px; padding-top: 48px; background-color: #62DFFF; background-image: url(../images/bkg.jpg) background-position: center bottom; background-repeat: repeat-x; height:150px; } It's a header element with a background image. The problem: This background image arbitrarily appears and disappears when reloading. Say you reload ten times in twenty seconds; the image will appear in two instances, and be missing in the 18 others. I would have put this down to server problems, but the weird thing is that when it's missing, the request for the image doesn't appear in Firebug's net tab at all. Even if it were cached, the request should be there. Raw screenshots of the identical page on two reloads: I am 100% sure the CSS file does not change in between. I have examined both instances with Firebug and the CSS is identical. It happens in both Firefox and Chrome so it must be something basic I'm overlooking. What could be causing a browser not to load a resource at all? I have zero idea about Ruby nor Rails - getting Redmine running and customized is all I have ever had to do with this platform - so I don't really know where to look. Apache's, Mongrel's and Redmine's error logs look fine, though.

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  • OpenGL Calls Lock/Freeze

    - by Necrolis
    I am using some dell workstations(running WinXP Pro SP 2 & DeepFreeze) for development, but something was recenlty loaded onto these machines that prevents any opengl call(the call locks) from completing(and I know the code works as I have tested it on 'clean' machines, I also tested with simple opengl apps generated by dev-cpp, which will also lock on the dell machines). I have tried to debug my own apps to see where exactly the gl calls freeze, but there is some global system hook on ZwQueryInformationProcess that messes up calls to ZwQueryInformationThread(used by ExitThread), preventing me from debugging at all(it causes the debugger, OllyDBG, to go into an access violation reporting loop or the program to crash if the exception is passed along). the hook: ntdll.ZwQueryInformationProcess 7C90D7E0 B8 9A000000 MOV EAX,9A 7C90D7E5 BA 0003FE7F MOV EDX,7FFE0300 7C90D7EA FF12 CALL DWORD PTR DS:[EDX] 7C90D7EC - E9 0F28448D JMP 09D50000 7C90D7F1 9B WAIT 7C90D7F2 0000 ADD BYTE PTR DS:[EAX],AL 7C90D7F4 00BA 0003FE7F ADD BYTE PTR DS:[EDX+7FFE0300],BH 7C90D7FA FF12 CALL DWORD PTR DS:[EDX] 7C90D7FC C2 1400 RETN 14 7C90D7FF 90 NOP ntdll.ZwQueryInformationToken 7C90D800 B8 9C000000 MOV EAX,9C the messed up function + call: ntdll.ZwQueryInformationThread 7C90D7F0 8D9B 000000BA LEA EBX,DWORD PTR DS:[EBX+BA000000] 7C90D7F6 0003 ADD BYTE PTR DS:[EBX],AL 7C90D7F8 FE ??? ; Unknown command 7C90D7F9 7F FF JG SHORT ntdll.7C90D7FA 7C90D7FB 12C2 ADC AL,DL 7C90D7FD 14 00 ADC AL,0 7C90D7FF 90 NOP ntdll.ZwQueryInformationToken 7C90D800 B8 9C000000 MOV EAX,9C So firstly, anyone know what if anything would lead to OpenGL calls cause an infinite lock,and if there are any ways around it? and what would be creating such a hook in kernal memory ? Update: After some more fiddling, I have discovered a few more kernal hooks, a lot of them are used to nullify data returned by system information calls(such as the remote debugging port), I also managed to find out the what ever is doing this is using madchook.dll(by madshi) to do this, this dll is also injected into every running process(these seem to be some anti debugging code). Also, on the OpenGL side, it seems Direct X is fine/unaffected(I ran one of the DX 9 demo's without problems), so could one of these kernal hooks somehow affect OpenGL?

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  • Extension methods for encapsulation and reusability

    - by tzaman
    In C++ programming, it's generally considered good practice to "prefer non-member non-friend functions" instead of instance methods. This has been recommended by Scott Meyers in this classic Dr. Dobbs article, and repeated by Herb Sutter and Andrei Alexandrescu in C++ Coding Standards (item 44); the general argument being that if a function can do its job solely by relying on the public interface exposed by the class, it actually increases encapsulation to have it be external. While this confuses the "packaging" of the class to some extent, the benefits are generally considered worth it. Now, ever since I've started programming in C#, I've had a feeling that here is the ultimate expression of the concept that they're trying to achieve with "non-member, non-friend functions that are part of a class interface". C# adds two crucial components to the mix - the first being interfaces, and the second extension methods: Interfaces allow a class to formally specify their public contract, the methods and properties that they're exposing to the world. Any other class can choose to implement the same interface and fulfill that same contract. Extension methods can be defined on an interface, providing any functionality that can be implemented via the interface to all implementers automatically. And best of all, because of the "instance syntax" sugar and IDE support, they can be called the same way as any other instance method, eliminating the cognitive overhead! So you get the encapsulation benefits of "non-member, non-friend" functions with the convenience of members. Seems like the best of both worlds to me; the .NET library itself providing a shining example in LINQ. However, everywhere I look I see people warning against extension method overuse; even the MSDN page itself states: In general, we recommend that you implement extension methods sparingly and only when you have to. So what's the verdict? Are extension methods the acme of encapsulation and code reuse, or am I just deluding myself?

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  • Special technology needed for browser based chat?

    - by orokusaki
    On this post, I read about the usage of XMPP. Is this sort of thing necessary, and more importantly, my main question expanded: Can a chat server and client be built efficiently using only standard HTTP and browser technologies (such as PHP and JS, or RoR and JS, etc)? Or, is it best to stick with old protocols like XMPP find a way to integrate them with my application? I looked into CampFire via LiveHTTPHeaders and Firebug for about 5 minutes, and it appears to use Ajax to send a request which is never answered until another chat happens. Is this just CampFire opening a new thread on the server to listen for an update and then returning a response to the request when the thread hears an update? I noticed that they're requesting on a specific port (8043 if memory serves me) which makes me think that they're doing something more complex than just what I mentioned. Also, the URL requested started with /tcp/ which I found interesting. Note: I don't expect to ever have more than 150 users live-chatting in all the rooms combined at the same time. I understand that if I was building a hosted pay for chat service like CampFire with thousands of concurrent users, it would behoove me to invest time in researching special technologies vs trying to reinvent the wheel in a simple way in my app. Also, if you're going to do it with server polling, how often would you personally poll to maximize response without slamming the server?

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  • Form submitted via dialog opens dialog again

    - by VikingGoat
    I have a form in a jquerymobile dialog box that I am submitting via jQuery Ajax. Currently my problem is that once the form is submitted the same dialog box is opened again on top of the original dialogbox. So that my url reads before submission: url/index.php#&ui-state=dialog and then after submission: url/index.php#&ui-state=dialog#&ui-state=dialog&ui-state=dialog Has anyone ever encountered something like this before? [edit added code example] $(function(){ $("#form").submit(function(e){ e.preventDefault(); var dataString = $("#form").serialize(); errorInput = $("input[name=valOne]#valOne").val(); $.ajax({ type: "GET", url: "formHandler.php", data: dataString, dataType: "text", success: function(data){ if(data.toLowerCase().indexOf("error") >= 0){ alert(data); $(".ui-dialog").dialog("close"); $("#valOne").val(errorInput); //the reentering info so user doesn't have to }else{ $(".ui-dialog").dialog("close"); location.href="index.php"; } }, error:function (xhr, ajaxOptions, thrownError){ alert(thrownError); } }); }); });

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  • Seed has_many relation using mass assignment

    - by rnd
    Here are my two models: class Article < ActiveRecord::Base attr_accessible :content has_many :comments end class Comment < ActiveRecord::Base attr_accessible :content belongs_to :article end And I'm trying to seed the database in seed.rb using this code: Article.create( [{ content: "Hi! This is my first article!", comments: [{content: "It sucks"}, {content: "Best article ever!"}] }], without_protection: true) However rake db:seed gives me the following error message: rake aborted! Comment(#28467560) expected, got Hash(#13868840) Tasks: TOP => db:seed (See full trace by running task with --trace) It is possible to seed the database like this? If yes a follow-up question: I've searched some and it seems that to do this kind of (nested?) mass assignment I need to add 'accepts_nested_attributes_for' for the attributes I want to assign. (Possibly something like 'accepts_nested_attributes_for :article' for the Comment model) Is there a way to allow this similar to the 'without_protection: true'? Because I only want to accept this kind of mass assignment when seeding the database.

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  • Is this a variation of the traveling salesman problem?

    - by Ville Koskinen
    I'm interested in a function of two word lists, which would return an order agnostic edit distance between them. That is, the arguments would be two lists of (let's say space delimited) words and return value would be the minimum sum of the edit (or Levenshtein) distances of the words in the lists. Distance between "cat rat bat" and "rat bat cat" would be 0. Distance between "cat rat bat" and "fat had bad" would be the same as distance between "rat bat cat" and "had fat bad", 4. In the case the number of words in the lists are not the same, the shorter list would be padded with 0-length words. My intuition (which hasn't been nurtured with computer science classes) does not find any other solution than to use brute force: |had|fat|bad| a solution ---+---+---+---+ +---+---+---+ cat| 2 | 1 | 2 | | | 1 | | ---+---+---+---+ +---+---+---+ rat| 2 | 1 | 2 | | 3 | | | ---+---+---+---+ +---+---+---+ bat| 2 | 1 | 1 | | | | 4 | ---+---+---+---+ +---+---+---+ Starting from the first row, pick a column and go to the next rows without ever revisiting a column you have already visited. Do this over and over again until you've tried all combinations. To me this sounds a bit like the traveling salesman problem. Is it, and how would you solve my particular problem?

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  • Using Moq to set indexers in C#

    - by emddudley
    I'm having trouble figuring out how to set indexers in C# with Moq. The Moq documentation is weak, and I've done a lot of searching... what I'd like to do is similar in the solution to How to Moq Setting an Indexed property: var someClass = new Mock<ISomeClass>(); someClass.SetupSet(o => o.SomeIndexedProperty[3] = 25); I want to modify the above to work for any index and any value so I can just do something like this: someClass.Object.SomeIndexedProperty[1] = 5; Currently I have the following, which works great for the indexed property getter, but if I ever set the value Moq ignores it: var someValues = new int[] { 10, 20, 30, 40 }; var someClass = new Mock<ISomeClass>(); someClass.Setup(o => o.SomeIndexedProperty[It.IsAny<int>()]) .Returns<int>(index => someValues[index]); // Moq doesn't set the value below, so the Assert fails! someClass.Object.SomeIndexedProperty[3] = 25; Assert.AreEqual(25, someClass.Object.SomeIndexedProperty[3]);

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  • How do I create a good evaluation function for a new board game?

    - by A. Rex
    I write programs to play board game variants sometimes. The basic strategy is standard alpha-beta pruning or similar searches, sometimes augmented by the usual approaches to endgames or openings. I've mostly played around with chess variants, so when it comes time to pick my evaluation function, I use a basic chess evaluation function. However, now I am writing a program to play a completely new board game. How do I choose a good or even decent evaluation function? The main challenges are that the same pieces are always on the board, so a usual material function won't change based on position, and the game has been played less than a thousand times or so, so humans don't necessarily play it enough well yet to give insight. (PS. I considered a MoGo approach, but random games aren't likely to terminate.) Any ideas? Game details: The game is played on a 10-by-10 board with a fixed six pieces per side. The pieces have certain movement rules, and interact in certain ways, but no piece is ever captured. The goal of the game is to have enough of your pieces in certain special squares on the board. The goal of the computer program is to provide a player which is competitive with or better than current human players.

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