Search Results

Search found 19923 results on 797 pages for 'instance variables'.

Page 248/797 | < Previous Page | 244 245 246 247 248 249 250 251 252 253 254 255  | Next Page >

  • C++ Singleton design pattern

    - by Artem Barger
    Recently I've bumped into a realization/implementation of the Singleton design pattern for C++. It has looked like this (I have adopted it from the real life example): // a lot of methods are omitted here class Singleton { public: static Singleton* getInstance( ); ~Singleton( ); private: Singleton( ); static Singleton* instance; }; From this declaration I can deduce that the instance field is initiated on the heap. That means there is a memory allocation. What is completely unclear for me is when exactly the memory is going to be deallocated? Or is there a bug and memory leak? It seems like there is a problem in the implementation. My main question is, how do I implement it in the right way?

    Read the article

  • Math behind multivariate testing for website optimization

    - by corkjack
    I am looking for theoretical resources (books, tutorials, etc.) to learn about making sound statistical inferences given (plenty of) multivariate website conversion data. I'm after the math involved, and cannot find any good non-marketing stuff on the web. The sort of questions I want to answer: how much impact does a single variable (e.g. color of text) have? what is the correlation between variables? what type of distribution is used for modelling (Gaussian, Binomial, etc.)? When using statistics to analyze results - what should be considered as a random variable - the web-page element that gets different variations or the binary conversion-or-no-conversion outcome of an impression? There's plenty of information about different website optimization testing methods and their benefits\pitfalls, plenty of information about multivariate statistics in general, do you guys know of resources that discuss statistics in this specific context of website optimization ? Thanks for any info!

    Read the article

  • Shared data in an ASP.NET application

    - by Barguast
    I have a basic ASP.NET application which is used to request data which is stored on disk. This is loaded from files and sent as the response. I want to be able to store the data loaded from these files in memory to reduce the number of reads from disk. All of the requests will be asking for the same data, so it makes sense to have a single cache of in-memory data which is accessible to all requests. What is the best way to create a single accessible object instance which I can use to store and access this cached data? I've looked into HttpApplication, but apparently a new instance of this is created for parallel requests and so it doesn't fit my needs.

    Read the article

  • Messaging in local network with .NET

    - by Richard
    Hi All, I need to implement some form of communication mechanism in my application, to send notifications/messages from one application instance to all the others. This is a normal scenario where someone adds and item or deletes and item and you want to notify other users that this has happened. The application runs on the client and connects to a database on the local network. So its not like all clients access a server instance of the application. So from what I know I could use MessageQueues or some form of Database polling where I have a table that stores all the messages (not ideal). Issue is I need to implement this very quickly, so sadly can't go very complex but need the quickest easiest solution. thanks for the help!

    Read the article

  • How to choose programaticaly the column to be querried by Linq using PropertyInfo???

    - by Richard77
    Hello, I would like to control how linq querries my database programaticaly. For instance, I'd like to querry the column X, column Y, or column Z, depending on some conditions. First of all, I've created an array of all the properties inside my class called myPropertyInfo. Type MyType = (typeOf(MyClass)); PropertyInfo[] myPropertyInfo = myType.GetProperties( BindingFlags.Public|BindingFlags.Instance); the myPropertyInfo array allows me to access each property details (Name, propertyType, etc) through the index*[i]* Now, how can I use the above information to control how linq querries my DB? Here's a sample of a querry I'd like to exploit. var myVar = from tp in db.MyClass select tp.{expression}; Expression using myPropertyInfo[i] to choose which property(column) to querry. I'm not sure if that's the way of doing it, but if there's another way to do so, I'll be glad to learn. Thanks for helping.

    Read the article

  • TableView problem with Tab Bar!?!?!

    - by Daniel Granger
    I created a tableView which worked fine in a single view app but as soon as I changed the view controller for a Tab Bar Controller and tapped the tab for the view with the table view in I suddenly get this! What has gone wrong? [Session started at 2010-03-28 15:30:15 +0100.] 2010-03-28 15:30:17.763 LogbookTable[13473:207] *** -[UIViewController tableView:numberOfRowsInSection:]: unrecognized selector sent to instance 0x3b14d10 2010-03-28 15:30:17.765 LogbookTable[13473:207] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[UIViewController tableView:numberOfRowsInSection:]: unrecognized selector sent to instance 0x3b14d10' 2010-03-28 15:30:17.766 LogbookTable[13473:207] Stack: ( 29303899, 2465178889, 29685819, 29255286, 29107906, 4372518, 4379894, 4378891, 3095430, 3035941, 3077376, 3065931, 55820976, 55820399, 55818438, 55817530, 2739877, 2763572, 2745983, 2773089, 37399897, 29088640, 29084744, 2739733, 2777007, 10496, 10350 )

    Read the article

  • How to retrieve base class only (entity framework)?

    - by Juvaly
    Hi All, I've been scratching my head here for a while now... I have a Consumer class and a BillableConsumer class that inherits Consumer. They are both a part of the Consumers set. The problem is that this following query: Consumer consumer = (from c in _ctx.Consumers where c.ID = id select c).First(); returns a BillableConsumer instance! Just the same as this query: BillableConsumer bconsumer = (from c in _ctx.Consumers.OfType<BillableConsumer>() where c.ID = id select c).First(); How can I return an instance of just the base class? (these are separate tables in the data store).

    Read the article

  • Call function from object instantiated in one class in another

    - by Dk43
    I have two classes, both of which need to be able to call the same instance of entitymanager class Engine { EntityManager::Entitymanager EManager; } And I need to add an object to a vector contained by this particular instance of Engine. What I want to do is be able to add a bullet spawned by the player to the vector that contains all my entities. class Player : Entity { void SpawnBullet() {Engine::EManager.Add(BULLET);} } The above returns this error: error: object missing in reference to ‘Engine::EManager’ How do I resolve this? Any help or pointers in the right direction would be much appreciated!

    Read the article

  • Ruby forwarding method calls

    - by JP
    I have an instance of a master class which generates instances of a subclass, these subclasses need to forward some method calls back to the master instance. At the moment I have code looking something like this, but it feels like I should be able to do the same thing more efficiently (maybe with method_missing?) class Master def initalize(mynum) @mynum = mynum end def one_thing(subinstance) "One thing with #{subinstance.var} from #{@mynum}" end def four_things(subinstance) "Four things with #{subinstance.var} from #{@mynum}" end def many_things(times,subinstance) "#{times} things with #{subinstance.var} from #{@mynum}" end def make_a_sub(uniqueness) Subthing.new(uniqueness,self) end class Subthing def initialize(uniqueness,master) @u = uniqueness @master = master end # Here I'm forwarding method calls def one_thing master.one_thing(self) end def four_things master.four_things(self) end def many_things(times) master.many_things(times,self) end end end m = Master.new(42) s = m.make_a_sub("very") s.one_thing === m.one_thing(s) s.many_things(8) === m.many_things(8,s) I hope you can see what's going on here. I would use method_missing, but I'm not sure how to cope with the possibility of some calls having arguments and some not (I can't really rearrange the order of the arguments to the Master methods either) Thanks for reading!

    Read the article

  • Django GenericRelation doesn't save related object's id - is this a bug or am I doing it wrong?

    - by pinkeen
    I have a model with a generic relation (call it A), when creating an instance of this object I pass an instance of another model (call it B) as the initializer of the content_object field (via kwargs of the constructor). If I don't save B before creating A then when saving A the content_object_id is saved to the db as NULL. If I save B before passing it to the constructor of A then everything's allright. It's not logical. I assumed that the ID of the related object (B) is fetched when doing A.save() and it should throw some kind of an exception if B isn't saved yet but it just fails silently. I don't like the current solution (saving B beforhand) because we don't know yet if I will be always willing to keep the object, not just scrap it, and there are performance considerations - what if I will add some another data and save it once more shortly after. class BaseNodeData(models.Model): ... extnodedata_content_type = models.ForeignKey(ContentType, null=True) extnodedata_object_id = models.PositiveIntegerField(null=True) extnodedata = generic.GenericForeignKey(ct_field='extnodedata_content_type', fk_field='extnodedata_object_id') class MarkupNodeData(models.Model): raw_content = models.TextField() Suppose we do: markup = MarkupNodeData(raw_content='...') base = BaseNodeData(..., extnodedata=markup) markup.save() base.save() # both records are inserted to the DB but base is stored with extnodedata_object_id=NULL markup = MarkupNodeData(raw_content='...') base = BaseNodeData(..., extnodedata=markup) base.save() markup.save() # no exception is thrown and everything is the same as above markup = MarkupNodeData(raw_content='...') markup.save() base = BaseNodeData(..., extnodedata=markup) base.save() # this works as expected Of course I can do it this way, but it doesn't change anything: base = BaseNodeData(...) base.extnodedata = markup My question is - is this a bug in django which I should report or maybe I'm doing something wrong. Docs on GenericRelations aren't exactly verbose.

    Read the article

  • Is MSDN referencing a system.thread, a worker thread, an io thread or all three?

    - by w0051977
    Please see the warning below taken from the StreamWriter class specification (http://msdn.microsoft.com/en-us/library/system.io.streamwriter.aspx): "Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe." I understand that a W3WC process contains two thread pools i.e. worker threads and I/O threads. A worker thread could contain many threads of its own (if the application creates its own System.Thread instances). Does the warning only relate to System.Threads or does it relate to worker threads and I/O threads as well I.e. as the instance variables of the streamwriter class are not thread safe then does this mean that there would be problems if multiple worker threads access it eg if two users on two different web clients attempt to write to the log file at the same time, then could one lock out the other?

    Read the article

  • How do I reference a pointer from a different class?

    - by Justagruvn
    First off, I despise singletons with a passion. Though I should probably be trying to use one, I just don't want to. I want to create a data class (that is instantiated only once by a view controller on loading), and then using a different class, message the crap out of that data instance until it is brimming with so much data, it smiles. So, how do I do that? I made a pointer to the instance of the data class when I instantiated it. I'm now over in a separate view controller, action occurs, and I want to update the initial data object. I think I need to reference that object by way of pointer, but I have no idea how to do that. Yes, I've set properties and getters and setters, which seem to work, but only in the initial view controller class. Peace Love applesauce.

    Read the article

  • Core Data-Linking one-to-many relationships

    - by Stelmate
    I have a one-to-many relationship where each department has many employees. When I create a new employee object I just link it to the parent department manually by setting the property to the instance of the department I have fetched from my fetch request. However, this seems to be improper because when I try to access the set of employees from the department by simply accessing the .employees property on my department object instance it returns a 0 count. Isn't the fault suppose to fire once I access a property? Am I linking my parent/child objects incorrectly?

    Read the article

  • NSInvalidArgumentException – App terminates while i'm trying to copy a captured video to documents f

    - by ChrNis
    I'd like to try the wisdom of the crowds..because i'm frustrated right now. Thanks in advance. So here is my code: - (void)imagePickerController:(UIImagePickerController *)ipc didFinishPickingMediaWithInfo:(NSDictionary *)info{ NSLog(@"info: %@",info); NSString *newFilename = [NSString stringWithFormat:@"%@/%@.mov", [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"], [NSString stringWithFormat:@"%d", (long)[[NSDate date] timeIntervalSince1970]]]; NSLog(@"newFilename: %@",newFilename); NSFileManager *filemgr = [NSFileManager defaultManager]; NSError *err; if ([filemgr copyItemAtPath:[info objectForKey:@"UIImagePickerControllerMediaURL"] toPath:newFilename error:&err] == YES) NSLog (@"Move successful"); else NSLog (@"Move failed"); and this is the log: 2010-05-16 18:19:01.975 erlkoenig[7099:307] info: { UIImagePickerControllerMediaType = "public.movie"; UIImagePickerControllerMediaURL = "file://localhost/private/var/mobile/Applications/BE25F9B5-2D08-4B59-8B62-D04DF7BB7E5B/tmp/-Tmp-/capture-T0x108cb0.tmp.8M81HU/capturedvideo.MOV"; } newFilename: /var/mobile/Applications/BE25F9B5-2D08-4B59-8B62-D04DF7BB7E5B/Documents/1274026741.mov [NSURL fileSystemRepresentation]: unrecognized selector sent to instance 0x1c1f90 *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSURL fileSystemRepresentation]: unrecognized selector sent to instance 0x1c1f90

    Read the article

  • Is LocalDB supported by Visual Studio 2010 in Entity Framework 5?

    - by Mathias Lykkegaard Lorenzen
    Is LocalDB supported by Visual Studio 2010 in Entity Framework 5, on .NET 4.0? Or am I doing it wrong? I'm getting a "The network path can't be found" issue when instantiating my model container with a connection string for LocalDB. Here's the connection string: var connectionString = "metadata=res://*/Model.csdl|res://*/Model.ssdl|res://*/Model.msl;provider=System.Data.SqlClient;provider connection string=\"data source=(localdb)\v11.0;initial catalog=fablelane_com_db;integrated security=SSPI;multipleactiveresultsets=True;App=EntityFramework\""; Edit 1 I'm receiving the following error when connecting, more specifically: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server). Edit 2 I just figured out that changing to Visual Studio 11 beta doesn't work either. Still receiving the same error-message.

    Read the article

  • Java: Superclass to construct a subclass on certain conditions, possible?

    - by ramihope
    I have this condition public class A { public action() { System.out.println("Action done in A"); } } public class B extends A { public action() { System.out.println("Action done in B"); } } when I create an instance of B, the action will do just actions in B, as it overrides the action of the superclass. the problem is that in my project, the super class A is already used too many times, and I am looking for a way that under certain conditions, when i create an instance of A it makes a check and if it is true, replace itself with B. public class A { public A() { if ([condition]) { this = new B(); } } public action() { System.out.println("Action done in A"); } } A a = new A(); a.action(); // expect to see "Action done in B"... is this possible in some way?

    Read the article

  • What is the easiest and fastest way to display an SDL_Surface in a window with SDL2?

    - by Semmu
    I would like to have an SDL_Surface representing the contents of the window, just like in the old days with SDL1.2. What is the best and fastest way to do it in SDL2? What I found is that I need an SDL_Window, an SDL_Renderer for that window, an SDL_Texture to render, and an SDL_Surface to create a texture from. This seems a bit too much to me, since I just want to display a single image on the screen. Not to mention the impact on the performance. On my machine (Lenovo Y510p laptop) this whole procedure takes 9ms, without any memory allocation, only using pre-allocated variables and totally black SDL_Surface. Is there a way I could speed up things?

    Read the article

  • In Django, using __init__() method of non-abstract parent model to record class name of child model

    - by k-g-f
    In my Django project, I have a non-abstract parent model defined as follows: class Parent(models.Model): classType = models.CharField(editable=False,max_length=50) and, say, two children models defined as follows: class ChildA(Parent): parent = models.OneToOneField(Parent,parent_link=True) class ChildB(Parent): parent = models.OneToOneField(Parent,parent_link=True) Each time I create an instance of ChildA or of ChildB, I'd like the classType attribute to be set to the strings "ChildA" or "ChildB" respectively. What I have done is added an _ _ init_ _() method to Parent as follows: class Parent(models.Model): classType = models.CharField(editable=False,max_length=50) def __init__(self,*args,**kwargs): super(Parent,self).__init__(*args,**kwargs) self.classType = self.__class__.__name__ Is there a better way to implement and achieve my desired result? One downside of this implementation is that when I have an instance of the Parent, say "parent", and I want to get the type of the child object linked with "parent", calling "parent.classType" gives me "Parent". In order to get the appropriate "ChildA" or "ChildB" value, I need to write a "_getClassType()" method to wrap a custom sql query.

    Read the article

  • Build git on embedded system

    - by naive231
    I want to build git on our embedded system and I got git's source code from here. I run ./configure tool with following arguments: ./configure --build=arm-eabi --host=`uname -p`-`uname -s`-`uname -o` Configure tool runs, and returns an error says: checking whether system succeeds to read fopen'ed directory...configure: error: in`/home/git-1.8.0.2`. I set necessary environment variables like CC and CXX to our tool chain already, so ./configure complains nothing about compilers. But I have no idea about that error message. It looks like some permission problem, but I have full permission of /home/git-1.8.0.2 for sure. Any idea ?

    Read the article

  • How to choose programaticaly the column to be queried by Linq using PropertyInfo???

    - by Richard77
    Hello, I would like to control how linq querries my database programaticaly. For instance, I'd like to query the column X, column Y, or column Z, depending on some conditions. First of all, I've created an array of all the properties inside my class called myPropertyInfo. Type MyType = (typeOf(MyClass)); PropertyInfo[] myPropertyInfo = myType.GetProperties( BindingFlags.Public|BindingFlags.Instance); The myPropertyInfo array allows me to access each property details (Name, propertyType, etc) through the index*[i]* Now, how can I use the above information to control how linq queries my DB? Here's a sample of a querry I'd like to exploit. var myVar = from tp in db.MyClass select tp.{expression}; Expression using myPropertyInfo[i] to choose which property(column) to query. I'm not sure if that's the way of doing it, but if there's another way to do so, I'll be glad to learn. Thanks for helping.

    Read the article

  • Multiple inclusion of header file c++

    - by iSight
    Hi, I have a problem regarding multiple inclusion of header file in C++ code. say for example, i have three class X,Y,Z. X and Y are derived from Base class Z. And i want to create an instance of X in Y. The code will go like this. class Z{some code} class X:public Z{some code};//here #include header of class Z added class Y:public Z //here #include header of class Z added as well as of X class {private: X* mX;//instance of X some code}; So in this multiple definition of all methods of base class arises. how can i cope with this problem

    Read the article

  • website inserting pics

    - by onfire4JesusCollins
    Hello i am getting this error message : Object reference not set to an instance of an object. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.NullReferenceException: Object reference not set to an instance of an object. Source Error: Line 7: Line 8: Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Line 9: UserIdValue.Text = Membership.GetUser().ProviderUserKey.ToString() Line 10: cannotUploadImageMessage.Visible = False Line 11: End Sub can someone help me with this?

    Read the article

  • Starting a SKProductsRequest gives -[_NSCFArray length] invalid selector error a moment later. LoadMicroPaymentsProductsOperation error.

    - by quantumpotato
    I'm fetching a list of identifiers from my server, then passing them off in a products request to Apple. Here's my code, and below is the error I'm getting. The iPhone 4 is not crashing when this happens. -(void)didReceiveData:(NSArray *)data { NSLog(@"Received Identifiers: %@",data); NSSet *productIdentifiers = [NSSet setWithArray:data]; SKProductsRequest *productsRequest = [[SKProductsRequest alloc] initWithProductIdentifiers:productIdentifiers]; productsRequest.delegate = self; [productsRequest start]; NSLog(@"productsRequest should have started by now"); } Wed Dec 29 09:42:14 iPhone XXXX-iphone[6363] <Warning>: Received Identifiers: ( ( 1, 10, "com.XXXX.XXXX.10" ) ) Wed Dec 29 09:42:14 iPhone XXXX-iphone[6363] <Warning>: productsRequest should have started by now Wed Dec 29 09:42:18 iPhone itunesstored[6367] : -[__NSCFArray length]: unrecognized selector sent to instance 0x119070 Wed Dec 29 09:42:18 iPhone itunesstored[6367] : caught -[__NSCFArray length]: unrecognized selector sent to instance 0x119070 exception with stack trace: (0x33ac0975 0x3347b49d 0x33ac2133 0x33a69aa9 0x33a69860 0x2717b 0x27515 0x31469651 0x314693ed 0x31469e39 0x3362795f 0x336276c3 0x3363c4eb 0x33c32680 0x33c32ba0 0x33bd7251 0x33bcf978)

    Read the article

  • Loading multiple embedded flash apps onto an HTML page- problem with ordering

    - by shudson250
    We need to load an embedded version of a site written in Flash, and not originally designed to load multiple instances of itself, on a HTML page. The specific issue is how to get them to load in order when embedded, given that they are all being opened by the same instance of the flash player. It's a complicated mapping application, and at the moment, the maps and data get intermixed as the session variables are overwritten by another instance starting to load before the previous one has finished. We need a way to have them load sequentially, one finishing before another starts to load. The most we can specify in the URL is an &order=1 or similar. We have PHP and SQL on the backend. Edit: The embedded versions are being loaded in an iFrame of a parent site. One php file loads one swf, as many times as the parent site desires.

    Read the article

< Previous Page | 244 245 246 247 248 249 250 251 252 253 254 255  | Next Page >