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  • MVC pattern implementation. What is the n-relation between its components

    - by Srodriguez
    Dear all, I'm working in a C# project and we are , in order to get some unity across the different parts of our UI, trying to use the MVC pattern. The client is windows form based and I'm trying to create a simple MVC pattern implementation. It's been more challenging than expected, but I still have some questions regarding the MVC pattern. The problem comes mostly from the n-n relationships between its components: Here is what I've understood, but I'm not sure at all of it. Maybe someone can correct me? Model: can be shared among different Views. 1-n relationship between Model-View View: shows the state of the model. only one controller (can be shared among different views?). 1-1 relationship with the Model, 1-1 relationship with the controller Controller: handles the user actions on the view and updates the model. One controller can be shared among different views, a controller interacts only with one model? I'm not sure about the two last ones: Can a view have several controller? Or can a view share a controller with another view? Or is it only a 1:1 relationship? Can a controller handle several views? can it interact with several models? Also, I take advantage of this question to ask another MVC related question. I've suppressed all the synchronous calls between the different members of the MVC, making use of the events and delegates. One last call is still synchronous and is actually the most important one: The call between the view and the controller is still synchronous, as I need to know rather the controller has been able to handle the user's action or not. This is very bad as it means that I could block the UI thread (hence the client itself) while the controller is processing or doing some work. How can I avoid this? I can make use of the callback but then how do i know to which event the callback comes from? PS: I can't change the pattern at this stage, so please avoid answers of type "use MVP or MVVC, etc ;) Thanks!

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  • MVC pattern implementation. What is the n-relation between its components

    - by Srodriguez
    Dear all, I'm working in a C# project and we are , in order to get some unity across the different parts of our UI, trying to use the MVC pattern. The client is windows form based and I'm trying to create a simple MVC pattern implementation. It's been more challenging than expected, but I still have some questions regarding the MVC pattern. The problem comes mostly from the n-n relationships between its components: Here is what I've understood, but I'm not sure at all of it. Maybe someone can correct me? Model: can be shared among different Views. 1-n relationship between Model-View View: shows the state of the model. only one controller (can be shared among different views?). 1-1 relationship with the Model, 1-1 relationship with the controller Controller: handles the user actions on the view and updates the model. One controller can be shared among different views, a controller interacts only with one model? I'm not sure about the two last ones: Can a view have several controller? Or can a view share a controller with another view? Or is it only a 1:1 relationship? Can a controller handle several views? can it interact with several models? Also, I take advantage of this question to ask another MVC related question. I've suppressed all the synchronous calls between the different members of the MVC, making use of the events and delegates. One last call is still synchronous and is actually the most important one: The call between the view and the controller is still synchronous, as I need to know rather the controller has been able to handle the user's action or not. This is very bad as it means that I could block the UI thread (hence the client itself) while the controller is processing or doing some work. How can I avoid this? I can make use of the callback but then how do i know to which event the callback comes from? PS: I can't change the pattern at this stage, so please avoid answers of type "use MVP or MVVC, etc ;) Thanks!

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  • PHP code to convert a MySQL query to CSV

    - by Reilly
    What is the most efficient way to convert a MySQL query to CSV in PHP please? It would be best to avoid temp files as this reduces portability (dir paths and setting file-system permissions required). The CSV should also include one top line of field names. Cheers.

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  • Precise explanation of JavaScript <-> DOM circular reference issue

    - by Joey Adams
    One of the touted advantages of jQuery.data versus raw expando properties (arbitrary attributes you can assign to DOM nodes) is that jQuery.data is "safe from circular references and therefore free from memory leaks". An article from Google titled "Optimizing JavaScript code" goes into more detail: The most common memory leaks for web applications involve circular references between the JavaScript script engine and the browsers' C++ objects' implementing the DOM (e.g. between the JavaScript script engine and Internet Explorer's COM infrastructure, or between the JavaScript engine and Firefox XPCOM infrastructure). It lists two examples of circular reference patterns: DOM element → event handler → closure scope → DOM DOM element → via expando → intermediary object → DOM element However, if a reference cycle between a DOM node and a JavaScript object produces a memory leak, doesn't this mean that any non-trivial event handler (e.g. onclick) will produce such a leak? I don't see how it's even possible for an event handler to avoid a reference cycle, because the way I see it: The DOM element references the event handler. The event handler references the DOM (either directly or indirectly). In any case, it's almost impossible to avoid referencing window in any interesting event handler, short of writing a setInterval loop that reads actions from a global queue. Can someone provide a precise explanation of the JavaScript ↔ DOM circular reference problem? Things I'd like clarified: What browsers are effected? A comment in the jQuery source specifically mentions IE6-7, but the Google article suggests Firefox is also affected. Are expando properties and event handlers somehow different concerning memory leaks? Or are both of these code snippets susceptible to the same kind of memory leak? // Create an expando that references to its own element. var elem = document.getElementById('foo'); elem.myself = elem; // Create an event handler that references its own element. var elem = document.getElementById('foo'); elem.onclick = function() { elem.style.display = 'none'; }; If a page leaks memory due to a circular reference, does the leak persist until the entire browser application is closed, or is the memory freed when the window/tab is closed?

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  • Should we have Browser Side Validation

    - by Raju
    For a back office application which is going to be used in house and users trained to use it, does it make sense to have browser side validation. After training users will seldom make mistakes. These mistakes would get caught at the server side. Also bearing in mind that the bandwidth availability is a lesser concern I feel we should avoid browser side validations. This will save the effort of maintaining the same functionality at two places.

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  • Is using the break statement bad practice?

    - by Lchi
    I've been told by professors and peers at my university that using the break statement is bad practice, but through my coursework haven't come up with a great reason why. Those who claim that it is bad say that it's a "get out of jail free card" and that you can always avoid using it. My guesses for why its considered bad would be that you could possibly skip some cleanup code after the break, or similarly exit some control structure in an inconsistent state. Is there any reason why using break is(n't) bad practice?

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  • Resuming MySQL indexing

    - by gmemon
    Hello All, I have been building index on a 200 million row table for almost 14 hours. Due to resource over-consumption on the machine (because of a separate incident), the machine cashed. Clearly, I want to avoid another 14 hours to re-construct the index. Is there a way that I can resume the construction of index from the point (or slightly back) where the machine crashed? I can see the temporary files created. Thanks

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  • Webview duplicate HTML problem

    - by oriharel
    Hi all, I load a url over the web containing images (their source is another url). when then view loads the html, it loads it without the images. after few milliseconds, the images come along but then the html is redrawn, and it does so over the previous html, causing it the web view to hold 2 htmls one over the other (very ugly result). anyone knows why does that happen? how can I avoid that? thanks, Ori

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  • text is exceeding the listview bounds in Qt

    - by Solitaire
    Hi. I need to customize the listview,I am placing an icon and a text at the center of the listview. If the text length is bigger then the list rectangle length.. the text is coming over the icon first letter of the string is not visible.. How to avoid this situation? Is it possible to give marique effect for the string? Thanks in advance.

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  • exact full text search - sql server 2005

    - by csetzkorn
    Hi, Is it possible to do an 'exact full text search' with CONTAINS. I have removed all noise words etc. but the dbms still seems to manipulate the 'exact word' (e.g. 'j-blade - blade'). Can I disable this? Thanks. Christian PS: I would like to avoid like because it is too slow and with exact I mean that the text contains the exact word.

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  • How do I implement graphs and graph algorithms in a functional programming language?

    - by brad
    Basically, I know how to create graph data structures and use Dijkstra's algorithm in programming languages where side effects are allowed. Typically, graph algorithms use a structure to mark certain nodes as 'visited', but this has side effects, which I'm trying to avoid. I can think of one way to implement this in a functional language, but it basically requires passing around large amounts of state to different functions, and I'm wondering if there is a more space-efficient solution.

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  • Stubhub like map in HTML5?

    - by Switz
    I have an image of a floor plan. Best way to think if it is a hotel floor plan. (Similar to how stubhub does their ticket maps) I want the user to select rooms. Instead of slicing each room in Photoshop, is there a way to split up the image in HTML5 canvas or Javascript. Would like to avoid flash. Thanks for the responses! example: http://adamsaewitz.com/housing/housing.html (top left rooms, hover)

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  • What's the best free and opensource PHP ecommerce solution? (and why?)

    - by Andrea Ambu
    I'd like to avoid coding one from scratch, so I'd like to see what the open-source community can offer :-) Required features: Easy way to insert items with photo and description Templates easy-to-create Multi language (at least Italian and English) Shopping cart User managment PayPal support (not required but really appreciated :D) I'm going on PHP and MySQL because of the hosting service I can't change, so please don't talk to me about alternatives :P I'd like to know what's the one you like the most and why should it be better than the others UPDATE: I need also multi language, Italian and English are a must.

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  • avoiding the tedium of optional parameters

    - by Kyle
    If I have a constructor with say 2 required parameters and 4 optional parameters, how can I avoid writing 16 constructors or even the 10 or so constructors I'd have to write if I used default parameters (which I don't like because it's poor self-documentation)? Are there any idioms or methods using templates I can use to make it less tedious? (And easier to maintain?)

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  • PHP 'instanceof' failing with class constant

    - by Nathan Loding
    I'm working on a framework that I'm trying to type as strongly as I possibly can. (I'm working within PHP and taking some of the ideas that I like from C# and trying to utilize them within this framework.) I'm creating a Collection class that is a collection of domain entities/objects. It's kinda modeled after the List<T> object in .Net. I've run into an obstacle that is preventing me from typing this class. If I have a UserCollection, it should only allow User objects into it. If I have a PostCollection, it should only allow Post objects. All Collections in this framework need to have certain basic functions, such as add, remove, iterate. I created an interface, but found that I couldn't do the following: interface ICollection { public function add($obj) } class PostCollection implements ICollection { public function add(Post $obj) {} } This broke it's compliance with the interface. But I can't have the interface strongly typed because then all Collections are of the same type. So I attempted the following: interface ICollection { public function add($obj) } abstract class Collection implements ICollection { const type = 'null'; } class PostCollection { const type = 'Post'; public function add($obj) { if(!($obj instanceof self::type)) { throw new UhOhException(); } } } When I attempt to run this code, I get syntax error, unexpected T_STRING, expecting T_VARIABLE or '$' on the instanceof statement. A little research into the issue and it looks like the root of the cause is that $obj instanceof self is valid to test against the class. It appears that PHP doesn't process the entire self::type constant statement in the expression. Adding parentheses around the self::type variable threw an error regarding an unexpected '('. An obvious workaround is to not make the type variable a constant. The expression $obj instanceof $this->type works just fine (if $type is declared as a variable, of course). I'm hoping that there's a way to avoid that, as I'd like to define the value as a constant to avoid any possible change in the variable later. Any thoughts on how I can achieve this, or have I take PHP to it's limit in this regard? Is there a way of "escaping" or encapsulating self::this so that PHP won't die when processing it?

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  • android - pre-allocate space for a file before downloading it

    - by android developer
    how can i create a pre-allocated file on android? something like a sparse file ? i need to make an applicaton that will download a large file , and i want to avoid having an out-of-space error while the download is commencing . my solution needs to support resuming and writing to both internal and external storage. i've tried what is written here: Create file with given size in Java but none of the solutions there didn't work for some reason.

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  • Using Interface Builder tags

    - by pat
    I'm using interface builder's tag feature to access some UILabels I'm instantiating in a xib file. Since this a UITextViewCell I want to avoid superfluous method calls, but I want to do it right too. Thus when I do: UILabel *label = (UILabel *)[cell viewWithTag:1]; I'm wondering if I should wrap it up like so: if([[cell viewWithTag:1] isKindOfClass [UITableViewCell class]]) { UILabel *label = (UILabel *)[cell viewWithTag:1]; } Any discussion on this would be appreciated. Thanks

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  • WCF facility : Metadata publishing for this service is currently disabled

    - by cvista
    I asked this before and got no where so i'm asking again as i'm now desperate!! Hey if i create a new wcf project i can browse the meta instantly. if I try - when using the WCF facility - i get the following: Metadata publishing for this service is currently disabled. i followed the instructions there and in a million other places and get no where. if i copy the contents of my faciltity service into the newly created project it complains that aspNetCompatibilityEnabled isnt enabled. so i enable it and then mex is disabled again and i get: Metadata publishing for this service is currently disabled. again!! this is driving me crazy - i have tried tried tried to follow every example on the web!! here is my current configuration - there is no client yet: <system.serviceModel> <serviceHostingEnvironment aspNetCompatibilityEnabled="true" /> <services> <service name="IbzStar.WebServices.UserServices" behaviorConfiguration="ServiceBehavior"> <!-- Service Endpoints --> <endpoint address="" binding="wsHttpBinding" contract="IbzStar.WebServices.IUserServices"> <!-- Upon deployment, the following identity element should be removed or replaced to reflect the identity under which the deployed service runs. If removed, WCF will infer an appropriate identity automatically. --> <identity> <dns value="localhost"/> </identity> </endpoint> <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/> </service> </services> <behaviors> <serviceBehaviors> <behavior name="ServiceBehavior"> <!-- To avoid disclosing metadata information, set the value below to false and remove the metadata endpoint above before deployment --> <serviceMetadata httpGetEnabled="true"/> <!-- To receive exception details in faults for debugging purposes, set the value below to true. Set to false before deployment to avoid disclosing exception information --> <serviceDebug includeExceptionDetailInFaults="false"/> </behavior> </serviceBehaviors> </behaviors> </system.serviceModel> please someone help me out before my laptop gets launched into orbit!! w://

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