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• How to force a deep copy when copying structs with arrays?

  - by Danvil

  If have a struct A { public double[] Data; public int X; } How can I force a deep copy when using operator= or adding instances of A to a container? The problem is for example: A a = new A(); var list = new List<A>(); list.Add(a); // does not make a deep copy of Data A b = a; // does not make a deep copy of Data Do I really have to implement my own DeepClone method and call it every time? This would be extremly error-prone ...

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• Entity Framework .Include() with compile time checking?

  - by Mikey Cee

  Consider the following code, which is calling against an EF generated data context: var context = new DataContext(); var employees = context.Employees.Include("Department"); If I change the name of the entity Department then this code is going to start throwing a runtime error. So I'll have to do some kind of find and replace throughout my code to replace each occurrence of "Department". Is there any way to call the .Include() method in a safe manner, so I get compile time checking for all the entity names being referenced?

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• Java - Handling Non-Blocking Calls

  - by sarav

  In my application I am using a third-party API. It is a non-blocking method which returns immediately. I have a collection of elements over which I have to invoke this method. Now, my problem is that I have to find a way till all the method execution gets completed and do my next operation. How can I handle this? I cannot modify the third-party API. In short it looks like this for(Object object: objects){ methodA(object); //this is a non-blocking call and returns immediately } // here I want to do my next task only after all the methodA calls completed execution

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• What is a simple C library for a set of integer sets?

  - by conradlee

  I've got to modify a C program and I need to include a set of unsigned integer sets. That is, I have millions of sets of integers (each of these integer sets contains between 3 and 100 integers), and I need to store these in some structure, lets call it the directory, that can in logarithmic time tell me whether a given integer set already exists in the directory. The only operations that need to be defined on the directory is lookup and insert. This would be easy in languages with built-in support for useful data structures, but I'm a foreigner to C and looking around on Google did (surprisingly) not answer my question satisfactorily. This project looks about right: http://uthash.sourceforge.net/ but I would need to come up with my own hash key generator. This is a standard, simple problem, so I hope there is a standard and simple solution.

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• Creating and releasing objects in the same method, while using self as delegate

  - by user200341

  In objective-c you are responsible for releasing objects you allocate, but what happens when you allocate an object in a method, assign self as the objects delegate, and then release the object. The callbacks from the newly created (and released) object fails at this point, or rather, doesn't happen. - (void)doSomething { MyObj *myObj = [[MyObj alloc] init]; myObj.delegate = self; [myObj performOperation]; [myObj release]; } - (void)callbackMethodFromMyObj:(NSString *)message { NSLog(message); } I can't release the object until the callback has occurred, and I can't avoid releasing the object in the same method that creates it (because it exists outside the scope). One way of doing it would be to pass the object along in the call-back and release it in the callback, but is this the right way to go about this?

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• C++ - defining static const integer members in class definition

  - by HighCommander4

  My understanding is that C++ allows static const members to be defined inside a class so long as it's an integer type. Why, then, does the following code give me a linker error? #include <algorithm> #include <iostream> class test { public: static const int N = 10; }; int main() { std::cout << test::N << "\n"; std::min(9, test::N); } The error I get is: test.cpp:(.text+0x130): undefined reference to `test::N' collect2: ld returned 1 exit status Interestingly, if I comment out the call to std::min, the code compiles and links just fine (even though test::N is also referenced on the previous line). Any idea as to what's going on? My compiler is gcc 4.4 on Linux.

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• How to define a function which repeats itself when passed an argument

  - by ~unutbu

  Is there an easy way to define a function which repeats itself when passed an argument? For example, I've defined the following function (defun swap-sign () (interactive) (search-forward-regexp "[+-]") (if (equal (match-string 0) "-") (replace-match "+") (replace-match "-")) ) I'd like C-u swap-sign to call swap-sign four times. I've tried (defun swap-sign (&optional num) (interactive) (let ((counter 0) (num (if num (string-to-number num) 0))) (while (<= counter num) (search-forward-regexp "[+-]") (if (equal (match-string 0) "-") (replace-match "+") (replace-match "-")) (setq counter (1+ counter))))) but C-u swap-sign still only runs swap-sign (or perhaps more precisely, the body of the while-loop) once. I'm guessing it is because if num is not the right way to test if num is an empty string. Am I on the right track, or is there a better/easier way to extend swap-sign?

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• How to Execute Base Class's Method Before Implementors's Method?

  - by DaveDev

  I have the following page public partial class GenericOfflineCommentary : OfflineFactsheetBase { } where OfflineFactsheetBase is defined as public class OfflineFactsheetBase : System.Web.UI.Page { public OfflineFactsheetBase() { this.Load += new EventHandler(this.Page_Load); this.PreInit += new EventHandler(this.Page_PreInit); } protected void Page_PreInit(object sender, EventArgs e) { if (Request.QueryString["data"] != null) { this.PageData = StringCompressor.DecompressString(Request.QueryString["data"]); this.ExtractPageData(); } } } OfflineFactsheetBase has the following virtual method: public virtual void ExtractPageData() { // get stuff relevant to all pages that impmement OfflineFactsheetBase } which is implemented in all pages that impmement OfflineFactsheetBase as follows: public partial class GenericOfflineCommentary : OfflineFactsheetBase { public override void ExtractPageData() { // get stuff relevant to an OfflineCommentary page. } } Currently, only GenericOfflineCommentary's ExtractPageData() is firing. How can I modify this to first run OfflineFactsheetBase's ExtractPageData() and then GenericOfflineCommentary's? edit: I'm trying to avoid having to call base.ExtractPageData() in every implementor. Is this possible?

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• Modulation of adding new Strings -> Method calls.

  - by guesswork

  If I have a program that does the following: if(input=='abc'){do x} if(input=='def'){do y} In the future, I may want to add another piece of code like so: if(input=='ghy'){do x} As you can see, I am adding a new 'if' statement for a different conditional BUT using the SAME function X. The code in future has potential to have lots of different IF statements (or switches) all of which are comparing a string vs a string and then performing a function. Considering the future expansion, I was wondering if there is a possible 'neater', 'modular' way of achieving the same results. It's a shame I can't combine the String with a Method call in a hashtable (String, method) in Java. That way I could just store any new procedures inside a hashtable and grab the relevant method for that String. Any ideas? Thank you

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• Is there a way to be notified when the user makes changes in a wxStyledTextCtrl?

  - by George Edison

  I have a wxWidgets application that has a wxStyledTextCtrl. But for the life of me, I cannot figure out how to get notified of modification events. I have the following code: void CMainWindow::OnDocumentModified(wxStyledTextEvent & event) { wxString msg; msg << event.GetModificationType(); wxMessageBox(msg); } This gets called for EVT_STC_MODIFIED. When I run the application and press a key, the message box displays 1040 and 8209. When I call SetText the same two messages are displayed. How can I differentiate between user events and programmatically-generated events?

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• Problem with a recursive function to find sqrt of a number

  - by Eternal Learner

  Below is a simple program which computes sqrt of a number using Bisection. While executing this with a call like sqrtr(4,1,4) in goes into an endless recursion . I am unable to figure out why this is happening. Below is the function : double sqrtr(double N , double Low ,double High ) { double value = 0.00; double mid = (Low + High + 1)/2; if(Low == High) { value = High; } else if (N < mid * mid ) { value = sqrtr(N,Low,mid-1) ; } else if(N >= mid * mid) { value = sqrtr(N,mid,High) ; } return value; }

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• command design pattern usage

  - by sagie

  Hi. I've read 3 descriptions of the command design pattern: wikipedia, dofactory and source making. In all of them, the UML shows a relation between the client to the receiver & the concrete command, but no relation to the invoker. But in all 3 examples the client is the one that initiates the invoker and call its Execute method. I think that should be a relation to the invoker as well. Am I missing somthing in here? Maybe even a basic UML knowladge?

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• How do I stop setNeedsDisplayInRect / drawRect coalescence?

  - by No One in Particular

  When programming my app, I get to the point where I have to update two rectangles on the screen. So I call [self setNeedsDisplayInRect:rect1] and then [self setNeedsDisplayInRect:rect2]. When my drawRect method is called, the rectangle parameter is the smallest rectangle which contains both rect1 and rect2. I can handle this with no problem, but when the two rectangles are far apart, then I am updating a lot of real estate with no gain. In this case, I would just like to repaint my two small rectangles. So my question is how can I prevent the underlying system from coalescing my two calls into one?

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• looping through new div as they are created

  - by eknown

  I have a div, let's call it class="phoneNo". Inside the div there are two links, one to add another div just like it, and another to delete the div itself. I'm trying to create a loop where if there's only 1 of these divs, the "delete" link should hide, and if there are more than 1 of these divs, the "delete" link should show up on all the divs. So far I came up with this, but no success: var pCount = $(".phoneNo").length; $(pCount).each(function(){ if (pCount <= 1) { $("a.deleteThis").hide(); } else if (pCount >= 1) { $("a.deleteThis").show(); } return true; });

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• What is the difference between type.__getattribute__ and object.__getattribute__?

  - by Neil G

  Given: In [37]: class A: ....: f = 1 ....: In [38]: class B(A): ....: pass ....: In [39]: getattr(B, 'f') Out[39]: 1 Okay, that either calls super or crawls the mro? In [40]: getattr(A, 'f') Out[40]: 1 This is expected. In [41]: object.__getattribute__(A, 'f') Out[41]: 1 In [42]: object.__getattribute__(B, 'f') --------------------------------------------------------------------------- AttributeError Traceback (most recent call last) <ipython-input-42-de76df798d1d> in <module>() ----> 1 object.__getattribute__(B, 'f') AttributeError: 'type' object has no attribute 'f' What is getattribute not doing that getattr does? In [43]: type.__getattribute__(B, 'f') Out[43]: 1 What?! type.__getattribute__ calls super but object's version doesn't? In [44]: type.__getattribute__(A, 'f') Out[44]: 1

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• Field contains foreign IDs for different tables

  - by Rich

  I am developing a php/mysql driven facebook game. I am stuck on an element the table design. When a user completes a task I want to trigger any number of events. I was thinking of something like so: tbl_events *event_id - serogate primary ID *task_id - foreign ID of the task just completed *event_type - what type of event e.g is it a facebook stream publish or a message to the user or does it unlock a new element of the game? *event_param - this is where it gets tricky... the event parameter is a problem for two reasons, 1) it will contain different foreign ids... dependent on the event_type and thus it will not be possible to join to x table. Meaning I would have to call two queries. 2) Most events require a single id or text, however some events require multiple parameters - like the facebook stream publish.

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• How to deal with callback to your UIController after your UIController unloads?

  - by erotsppa

  Suppose your controller is a table view and one of the cells you are going off to do a length task (say download a thumbnail) to be viewed in the cell. Typically you would have the network call do a callback to your controller when it is done downloading. The callback can then reload the table or do some other form of UI update (hides a spinner etc). However, what if the controller is unloaded? Say the user navigated away from this controller and it got released? What happens? Will the callback still work despite the controller now not in memory? Also, if the callback operates on some objects (say the UITableView) what happens when the controller is deallocated? I suppose the controller can release all the objects and the callback would just be calling methods on nil to prevent crash. But is this the convention?

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• Is this the correct why of speaking to a "Content Manager" Class?

  - by DeanMc

  I am creating a silverlight site. I am currently breaking out my ideas into pieces of functionality. One of the idea's I have is the concept of a content manager. This is essentially a UI control with 4 regions. Top, Bottom, Right & Left. I also have a collection of objects that are considered "Menu Items". These are controls that function as a way to navigate around, similar to links. The idea I have is to implement an IMenuItem interface. Among the standard pieces of information (Text, PageReference, etc) I was also going to hold a reference to the content manager. My idea behind this thinking is that I can pass the PageReference to a property on the ContentManager and then call a method which knows how to update the content manager accordingly. Is this the best way of implementing this or is their some sort of pattern for it?

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• Is my way of doing threads in Android correct?

  - by Charlie

  Hi, I'm writing a live wallpaper, and I'm forking off two separate threads in my main wallpaper service. One updates, and the other draws. I was under the impression that once you call thread.start(), it took care of everything for you, but after some trial and error, it seems that if I want my update and draw threads to keep running, I have to manually keep calling their run() methods? In other words, instead of calling start() on both threads and forgetting, I have to manually set up a delayed handler event that calls thread.run() on both the update and draw threads every 16 milliseconds. Is this the correct way of having a long running thread? Also, to kill threads, I'm just setting them to be daemons, then nulling them out. Is this method ok? Most examples I see use some sort of join() / interrupt() in a while loop...I don't understand that one...

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• C# - Ensuring an assembly is called via a specified assembly

  - by Adam Driscoll

  Is there any built in functionality to determine if an assembly is being called from a particular assembly? I have assembly A which references assembly B. Assembly A exposes PowerShell cmdlets and outputs types that are found within B. Certain methods and properties with in types of exposed by B are of interest to types in assembly A but not of interest to consumers of PowerShell or anyone attempting to load types in B directly and call methods within it. I have looked into InternalsVisibleToAttribute but it would require extensive rework because of the use of interfaces. I was devising a shared key system that would later be obfuscated but that seemed clunky. Is there any way to ensure B is called only by A?

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• Any side effect of not using USES_CONVERSION

  - by Yan Cheng CHEOK

  Recently, I have a utilities function of // T2CA #include "ATLCONV.H" std::string Utils::CString2String(const CString& cString) { #if _MSC_VER > 1200 // Convert a TCHAR string to a LPCSTR // construct a std::string using the LPCSTR input CT2CA tmp(cString); std::string strStd (tmp); #else // Deprecated in VC2008. // construct a std::string using the LPCSTR input std::string strStd (T2CA (cString)); #endif return strStd; } I do several simple test it seems work fine. However, when I google around, I see most usage of T2CA in VC6, before they call, they will invoke USES_CONVERSION; Is there any thing I had missed out? Shall I invoke my function by : #else // Deprecated in VC2008. // construct a std::string using the LPCSTR input USES_CONVERSION; std::string strStd (T2CA (cString)); #endif

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• Is it a good practice to perform direct database access in the code-behind of an ASP.NET page?

  - by patricks418

  Hi, I am an experienced developer but I am new to web application development. Now I am in charge of developing a new web application and I could really use some input from experienced web developers out there. I'd like to understand exactly what experienced web developers do in the code-behind pages. At first I thought it was best to have a rule that all the database access and business logic should be performed in classes external to the code-behind pages. My thought was that only logic necessary for the web form would be performed in the code-behind. I still think that all the business logic should be performed in other classes but I'm beginning to think it would be alright if the code-behind had access to the database to query it directly rather than having to call other classes to receive a dataset or collection back. Any input would be appreciated.

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• Python Terminated Thread Cannot Restart

  - by Mel Kaye

  Hello, I have a thread that gets executed when some action occurs. Given the logic of the program, the thread cannot possibly be started while another instance of it is still running. Yet when I call it a second time, I get a "RuntimeError: thread already started" error. I added a check to see if it is actually alive using the Thread.is_alive() function, and it is actually dead. What am I doing wrong? I can provide more details as are needed.

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• Ajax twice + facbook login/logout

  - by Devenv

  Hi, I have a very specific problem. The site I'm developing loads the FB connect button by ajax (it loads the box that includes FBC button). And when user logs in it loads instead of it the box with FB logout link. The problem is that FB requires to call FB.init() at the end of the body (when all the FB stuff is already on the page) and you can't do it twice as the second time is ignored. So what happens is - I do FB.init() inside the login box and FBC button works perfectly, but the logout link doesn't as FB.init() doesn't work there. The only solution I came up with is to place the login and logout buttons outside of ajax boxes and show them in the right places after ajax boxes are loaded. I'm pretty much sure this will work but I don't like the solution (which looks more like hack).

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• Castle Windsor Weak Typed Factory

  - by JeffN825

  In a very very limited number of scenarios, I need to go from an unknown Type (at compile time) to an instance of the object registered for that type. For the most part, I use typed factories and I know the type I want to resolve at compile time...so I inject a Func<IMyType> into a constructor ...but in these limited number of scenarios, in order to avoid a direct call to the container (and thus having to reference Windsor from the library, which is an anti-pattern I'd like to avoid), I need to inject a Func<Type,object>...which I want to internally container.Resolve(type) for the Type parameter of the Func. Does anyone have some suggestions on the easiest/most straightforward way of setting this up? I tried the following, but with this setup, I end up bypassing the regular TypedFactoryFacility altogether which is definitely not what I want: Kernel.Register(Component.For(typeof (Func<Type, object>)).LifeStyle.Singleton.UsingFactoryMethod( (kernel, componentModel, creationContext) => kernel.Resolve(/* not sure what to put here... */))); Thanks in advance for any assistance.

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