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  • c# Generic overloaded method dispatching ambiguous

    - by sebgod
    Hello, I just hit a situation where a method dispatch was ambiguous and wondered if anyone could explain on what basis the compiler (.NET 4.0.30319) chooses what overload to call interface IfaceA { } interface IfaceB<T> { void Add(IfaceA a); T Add(T t); } class ConcreteA : IfaceA { } class abstract BaseClassB<T> : IfaceB<T> { public virtual T Add(T t) { ... } public virtual void Add(IfaceA a) { ... } } class ConcreteB : BaseClassB<IfaceA> { // does not override one of the relevant methods } void code() { var concreteB = new ConcreteB(); // it will call void Add(IfaceA a) concreteB.Add(new ConcreteA()); } In any case, why does the compiler not warn me or even why does it compile? Thank you very much for any answers.

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  • System.Windows.Forms.DataGridView does not display data

    - by Water Cooler v2
    All I am doing is a simple: // Both the methods, order.GetAllOrderItems() and order.GetOrderedItemsWhereBrandIs("foo") // return an IEnumerable<T> so the assignment to the DataSource property of the DataGridView // should be fine. The problem is in re-assigning the data source property. public void DisplayItems() { // The data appears if I have just this line. dgvOrderedItems.DataSource = order.GetAllOrderItems(); dgvOrderedItems.DataSource = null; // This time the data grid does not take the new data source. Instead, because // of the null assignment in the previous statement, it displays no data at all. dgvOrderedItems.DataSource = order.GetOrderedItemsWhereBrandIs("Lenovo"); } My question is: is there a way to change the data source of a DataGridView control once it has been set? I am using C# 4.0 and Visual Studio 2010 for development.

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  • C Class Instance from Void Pointer using Ctypes

    - by g.d.d.c
    I've got a C DLL that exposes a handful of methods that return void pointers to a Class like so: void *GetLicense() { static AppLicenseImpl ipds_; return (void *) &ipds_; } In C++, after loading the DLL, I'd do this to work with it: typedef void *(* FPGetLicense)(); GetLicense_ = (FPGetLicense)GetAddress("GetLicense"); license_ = (AppLicense *) GetLicense_(); license_->GetApplicationStatus(); // Load data so that other calls don't fail I can't figure out how to parallel that in Python. This gets me the pointer: d = ctypes.cdll.LoadLibrary('license.dll') d.GetLicense.restype = ctypes.c_void_p p = d.GetLicense() # returns ptr loc, something like 8791433660848L But I obviously can't call p.GetApplicationStatus() in Python. Does anyone have a suggestion on how I'd instantiate that Class the rest of the way in Python so that I can call GetApplicationStatus()?

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  • Show friendly message on ASP.NET Ajax error

    - by balexandre
    You all know how annoying is this: I do have a log system and the correct error is well explicit there, but I want to give a better message to the user. I keep trying several ways but I'm using Telerik components and well jQuery and I ended up using both ASP.NET Ajax methods and jQuery, so I use function pageLoad() { try { var manager = Sys.WebForms.PageRequestManager.getInstance(); manager.add_endRequest(endRequest); manager.add_beginRequest(OnBeginRequest); manager } catch (err) { alert(err); } } as well $(document).ready(function() { ... } that alert(err) is never fired even upon OnClick events what's the best approach to avoid this message errors and provide a cleaner way? all this happens in <asp:UpdatePanel> as I use that when I didn't know better (3 years ago!) and I really don't want to mess up and build all again from scratch :( Any help is greatly appreciated Updated with more error windows after volpav solution

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  • C#: why Base class is allowed to implement an interface contract without inheriting from it?

    - by etarassov
    I've stumbled upon this "feature" of C# - the base class that implements interface methods does not have to derive from it. Example: public interface IContract { void Func(); } // Note that Base does **not** derive from IContract public abstract class Base { public void Func() { Console.WriteLine("Base.Func"); } } // Note that Derived does *not* provide implementation for IContract public class Derived : Base, IContract { } What happens is that Derived magically picks-up a public method Base.Func and decides that it will implement IContract.Func. What is the reason behind this magic? IMHO: this "quasi-implementation" feature is very-unintuitive and make code-inspection much harder. What do you think?

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  • Are there any OSGi web service / SOAP clients out there?

    - by James Carr
    I'm looking for any webservice client that can be run inside an OSGi container and connect to a simple web service using SOAP, doesn't sound so hard does it? Oh, and it has to work under Java 1.5, so the JRE jax-ws wont be present. The problem is I've tried a few solutions now, and although each solution works in standard Java using it from within OSGi doesn't. the springsource JAX-WS bundles seem to have dependency issues the CXF bundles get me as far as calling the service, but then can seem to find the stub methods in the proxy Is there anyone out there who has successfully created an OSGi webservice client?

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  • How to use Sleep in the application in iphone

    - by Pugal Devan
    Hi, I have used to loading a default image in my appication. So i have set to, Sleep(3); in my delegate.m method. But sometimes it will take more than 6 to 7 minutes. So i want to display the image 3 seconds only and then it goes to my appilcation based on my requirements. Which one is best way to do that? Sleep(3) or [NSThread sleepForTimeInterval:3.0] or something else; And i must display the image 3 seconds only. Please explain me. (Note: And I declared setter and getter methods only in my deleagte class.) Please explain me.

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  • In Vim, what is the best way to select, delete, or comment out large portions of multi-screen text?

    - by Edward Tanguay
    Selecting a large amount of text that extends over many screens in an IDE like Eclipse is fairly easy since you can use the mouse, but what is the best way to e.g. select and delete multiscreen blocks of text or write e.g. three large methods out to another file and then delete them for testing purposes in Vim when using it via putty/ssh where you cannot use the mouse? I can easily yank-to-the-end-of-line or yank-to-the-end-of-code-block but if the text extends over many screens, or has lots of blank lines in it, I feel like my hands are tied in Vim. Any solutions? And a related question: is there a way to somehow select 40 lines, and then comment them all out (with "#" or "//"), as is common in most IDEs?

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  • What really is the purpose of "base" keyword in c#?

    - by Pandiya Chendur
    Thus for used base class for some commom reusable methods in every page of my application... public class BaseClass:System.Web.UI.Page { public string GetRandomPasswordUsingGUID(int length) { string guidResult = System.Guid.NewGuid().ToString(); guidResult = guidResult.Replace("-", string.Empty); return guidResult.Substring(0, length); } } So if i want to use this method i would just do, public partial class forms_age_group : BaseClass { protected void Page_Load(object sender, EventArgs e) { //i would just call it like this string pass = GetRandomPasswordUsingGUID(10); } } It does what i want but there is a "Base" keyword that deals with base class in c# ... I really want to know when should use base keyword in my derived class.... Any good example...

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  • How to increase query speed without using full-text search?

    - by andre matos
    This is my simple query; By searching selectnothing I'm sure I'll have no hits. SELECT nome_t FROM myTable WHERE nome_t ILIKE '%selectnothing%'; This is the EXPLAIN ANALYZE VERBOSE Seq Scan on myTable (cost=0.00..15259.04 rows=37 width=29) (actual time=2153.061..2153.061 rows=0 loops=1) Output: nome_t Filter: (nome_t ~~* '%selectnothing%'::text) Total runtime: 2153.116 ms myTable has around 350k rows and the table definition is something like: CREATE TABLE myTable ( nome_t text NOT NULL, ) I have an index on nome_t as stated below: CREATE INDEX idx_m_nome_t ON myTable USING btree (nome_t); Although this is clearly a good candidate for Fulltext search I would like to rule that option out for now. This query is meant to be run from a web application and currently it's taking around 2 seconds which is obviously too much; Is there anything I can do, like using other index methods, to improve the speed of this query?

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  • iPhone programming guideline : List / detail / modify

    - by Oliver
    Hello, I have a program that displays a list (a TableView). When the user clicks an item, it's detail is shown. On the detail view, the user can ask to modify it so a modify window is shown. Here, the user can ask to delete the item. I would like at this time return to the list with the item deleted from the list and from the data source. There may be thousands of methods to do this, but I wonder which is the best / good one. Could you help me, and/or give me a good reference to read about this ? Thank you.

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  • Is MVC now the only way to write PHP?

    - by JasonS
    Hey... its XMAS Eve and something is bugging me... yes, I have work on my mind even when I am on holiday. The vast amount of frameworks available for PHP now use MVC. Even ASP.net has its own MVC module. I can see the attraction of MVC, I really can and I use it frequently. The only downside that I can see is that you have to fire up the whole system to execute a page request. Depending on your task this can be a little wasteful. So the question. In a professional environment is this the only way to use PHP nowadays or are their other design methods which have alternative benefits?

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  • How do you encrypt data between client and server running in Flash and Java?

    - by ArmlessJohn
    We have a multiclient system where the client is written in Flash and the server is written in Java. Currently, communication is done in Flash by usage of flash.net.Socket and the protocol is written in JSON. The server uses a custom port to receive connections and then proceed to talk with each client. As expected, data is sent and received on both fronts as raw bytes, which are then decoded as needed. We would like to encrypt the communication between clients and server. I have some basic understanding about public/private key encryption, but I do not know what is the best way to exchange keys or what libraries are available (on both languages) to do this. What would be the best strategy to attack this problem and where should I start looking for libraries/methods to implement this encryption?

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  • Which langauge should i use for Artificail intelligence on web projects

    - by Mirage
    I have to do one project for my thesis involving Artificail intelligence , collaborative filtering and machine learning methods. I only know PHP/mysq/JS and there is not much AI stuff examples in PHP. There are some books on AI on internet but they use Java , Python. Now i have to apply AI techniques on web application. WHich language should i choose java or python. I searhed on internet that i can call java classes inside my php so that can help as as i am very good at php i have also seen that python can also be used with php as well So which way should i go and roughly how much it will take me to learn java i have done java basics but that was 6 years ago

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  • Interacting With Class Objects in Ruby

    - by michaelmichael
    How can I interact with objects I've created based on their given attributes in Ruby? To give some context, I'm parsing a text file that might have several hundred entries like the following: ASIN: B00137RNIQ -------------------------Status Info------------------------- Upload created: 2010-04-09 09:33:45 Upload state: Imported Upload state id: 3 I can parse the above with regular expressions and use the data to create new objects in a "Product" class: class Product attr_reader :asin, :creation_date, :upload_state, :upload_state_id def initialize(asin, creation_date, upload_state, upload_state_id) @asin = asin @creation_date = creation_date @upload_state = upload_state @upload_state_id = upload_state_id end end After parsing, the raw text from above will be stored in an object that look like this: [#<Product:0x00000101006ef8 @asin="B00137RNIQ", @creation_date="2010-04-09 09:33:45 ", @upload_state="Imported ", @upload_state_id="3">] How can I then interact with the newly created class objects? For example, how might I pull all the creation dates for objects with an upload_state_id of 3? I get the feeling I'm going to have to write class methods, but I'm a bit stuck on where to start.

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  • With the attachment_fu rails plugin, is there any way to delete files uploaded to Amazon S3?

    - by Eric Nguyen
    Let's say I'm using attachment_fu to attach profile pics to user profiles in a system, with Amazon S3 used as the actual file storage. When users upload new profile pics, I'd like to replace the attached file with the new one. I can do this within my database (i.e. the file metadata) easily, but attachment_fu doesn't seem to provide methods for deleting the files from S3. Am I missing something, or am I approaching this the wrong way? Many thanks!

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  • Writing Resources from filesystem in Android

    - by Markus
    Hi, as I need to get a specific Frame from a Website I want to display in an WebView, I decided to grab the .html from the net and save it under file:///data/data//files/file.html. Stroed there I can edit it using regex or String methods. Now two questions: Is there a way to bind this file to an resource. e.g. to /res/raw/file.html and get it updated dynamically as i edit it? Or can i write the File directly to the resources? Is this whole stuff I do there any good or performant at all? I mean maybe there is a better way to get the .html code between two tags from a Webpage and display it via WebView. Kind regards Markus

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  • Core Data produces Analyzer warnings

    - by RickiG
    Hi I am doing the final touch ups on an app and I am getting rid of every compiler/analyzer warning. I have a bunch of Class methods that wrap my apps access to Core Data entities. This is "provoking" the analyzer. + (CDProductEntity*) newProductEntity { return (CDProductEntity*)[NSEntityDescription insertNewObjectForEntityForName:@"CDProductEntity" inManagedObjectContext:[self context]]; } Which results in an Analyzer warning: Object with +0 retain counts returned to caller where a +1 (owning) retain count is expected In the method that calls the above Class Method I have this: CDProductEntity *newEntity = [self newProductEntity]; Which results in an Analyzer warning: Method returns an Objective-C object with a +1 retain count (owning reference) Explicitly releasing or autoreleasing a Core Data entity is usually very very bad, but is that what it is asking me to do here? First it tells me it has a +0 retain count and that is bad, then it tells me it has a +1 which is also bad. What can I do to ensure that I am either dealing with a Analyzer hiccup or that I release correctly? Thanks in advance

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  • Help me understand Dispose() implementation code from MSDN

    - by Benny
    the following code is from MSDN: Idisposable pattern protected virtual void Dispose(bool disposing) { // If you need thread safety, use a lock around these // operations, as well as in your methods that use the resource. if (!_disposed) { if (disposing) { if (_resource != null) _resource.Dispose(); Console.WriteLine("Object disposed."); } // Indicate that the instance has been disposed. _resource = null; _disposed = true; } } why the following statement: _resource = null; _disposed = true; are not enclosed by if (disposing) statement block? for me i would probably write like this: if (disposing) { if (_resource != null) { _resource.Dispose(); _resource = null; _disposed = true; } Console.WriteLine("Object disposed."); } anything wrong with my version?

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  • Text rotation in IE 9

    - by John Bowden
    Hi there I'm attempting to rotate a piece of text on its end within a div using the following different methods. writing-mode: tb-rl; filter: FlipH FlipV; and: -ms-transform: rotate(-90deg); filter: progid:DXImageTransform.Microsoft.Matrix(M11=6.123233995736766e-17, M12=1, M21=-1, M22=6.123233995736766e-17, sizingMethod='auto expand'); Although the text rotates properly in all browsers using either method and even IE all the way up to and including 8. IE 9 produces a horrid pixelated text which is nigh unreadable. Alongside this, IE9 also subtly breaks the layout of various pieces in the application which could be part of the same underlying problem perhaps. If anyone knows a way around this I would be most appreciative. John

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  • What should I do that GWT use <th> instead of <td>?

    - by Paulus
    To build a HTML table I use direct DOM instead of a predefined Widget to set thead and tbody. But when I insert a cell with the insertCell() method GWT inserts an td element but should insert an th element. So TableElement table = Document.get().createTableElement(); TableSectionElement thead = table.createTHead(); TableRowElement headRow = thead.insertRow(-1); headRow.insertCell(-1).setInnerText( "header1" ); gives table/thead/tr/td but should give table/thead/tr/th Any idea how to solve this problem? Use the "old-school" DOM.createXXX()-Methods?

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  • Is there a concise way to create an InputSupplier for an InputStream in Google Guava?

    - by Fabian Steeg
    There are a few factory methods in Google Guava to create InputSuppliers, e.g. from a byte[]: ByteStreams.newInputStreamSupplier(bytes); Or from a File: Files.newInputStreamSupplier(file); Is there a similar way to to create an InputSupplier for a given InputStream? That is, a way that's more concise than an anonymous class: new InputSupplier<InputStream>() { public InputStream getInput() throws IOException { return inputStream; } }; Background: I'd like to use InputStreams with e.g. Files.copy(...) or ByteStreams.equal(...).

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  • How to detect page redirect with PHP?

    - by blabus
    I'm trying to detect whether an image exists on a remote server. However, I've tried several methods and can't get any of them to work. Right now I'm trying to use this: if (!CheckImageExists("http://img2.netcarshow.com/ABT-Audi_R8_2008_1024x768_wallpaper_01.jpg")) { print_r("DOES NOT EXIST"); } else { print_r("DOES EXIST"); }; function CheckImageExists($imgUrl) { if (fopen($imgUrl, "r")) { return true; } else { return false; }; }; But it returns 'true' whether the image actually exists or not (the above image should, but change it to gibberish and it still will return 'true'). I have a feeling it could be because if the URL does not exist, it redirects to the homepage of the site. But I don't know how to detect that. Thanks for any help!

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  • PHP Type Hinting: array supported, object NOT?

    - by Marius Burz
    Am I missing something or there really is no support for generic object type hinting in PHP 5.x? I find it really strange that hinting arrays is supported while hinting objects is not, at least not out of the box. I'd like to have something like this: function foo(object $o) Just as we have: function foo(array $o) Example of possible use: methods of an objects collection class. Workaround: using an interface "Object" implemented by all classes or extending all classes from a generic class "Object" and writing something like this: function foo(Object $o) Well, that just ain't cute. Edit: somebody suggested in a deleted post using stdClass. It doesn't work: Catchable fatal error: Argument 1 passed to c::add() must be an instance of stdClass, instance of b given

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  • Hibernate object equality checking

    - by Sujee
    As far as I understand(correct me if I am wrong) Hibernate uses object reference to check the object equality. When Hibernate identifies that there are more than one objects attached to same DB record, it throws following exception. "a different object with the same identifier value was already associated with the session" My question is, does Hibernate use equal() method to check the object equality (The default equal method uses object reference)? If it is true, will overridden equal() method change the Hibernate behavior? Note: My question is not about the issues of implementing equal() or hashCode() methods in a Hibernate persisted object. Thank you.

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