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  • Method params match signature, but still getting error

    - by Jason
    I am in the midst of converting a VB library to C#. One of my methods has the following signature in VB: Private Shared Sub FillOrder(ByVal row As DataRowView, ByRef o As Order) In C# I converted it to: private static void FillOrder(DataRowView row, ref Order o) From my constructor inside my Order class, I am calling the FillOrder() method like so: DataView dv = //[get the data] if (dv.Count > 0) { FillOrder(dv[0], this); } In VB, this works: Dim dv As DataView = '[get data]' If dv.Count > 0 Then FillOrder(dv.Item(0), Me) End If However, in VS10 in the C# file I am getting a red squiggle under this call with the following error: The best overloaded method match for [the method] has some invalid arguments This was working code in VB. What am I doing wrong?

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  • Lifetime of implicitly casted temporaries

    - by Answeror
    I have seen this question. It seems that regardless of the cast, the temporary object(s) will "survive" until the fullexpression evaluated. But in the following scenario: void foo(boost::tuple<const double&> n) { printf("%lf\n", n.get<0>()); } int main() { foo(boost::tuple<const double&>(2));//#1 foo(boost::make_tuple(2));//#2 return 0; } 1 run well, but 2 do not. And MSVC gave me a warning about 2: "reference member is initialized to a temporary that doesn't persist after the constructor exits" Now I am wondering why they both make a temporary "double" object and pass it to boost::tuple<const double&> and only 2 failed.

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  • Performance problem loading lots of user controls

    - by codymanix
    My application is loading a bunch of the same user control into a ScrollPanel. The problem is, this is very slow. The profiler show that the method Application.LoadComponent(), which is called internally by in the designer code in the constructor of my user control, is the bottleneck. The documentation of this method says, that this method load XAML files. I alway though the compiler compiles XAML to BAML and embedds it into the assembly. So the question is, how can I use BAML instead of XAML? Is there another way to make loading my user controls faster?

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  • C++ Array of pointers: delete or delete []?

    - by Jasper
    Cosider the following code: class Foo { Monster* monsters[6]; Foo() { for (int i = 0; i < 6; i++) { monsters[i] = new Monster(); } } virtual ~Foo(); } What is the correct destructor? this: Foo::~Foo() { delete [] monsters; } or this: Foo::~Foo() { for (int i = 0; i < 6; i++) { delete monsters[i]; } } I currently have the uppermost constructor and everything is working okey, but of course I cannot see if it happens to be leaking... Personally, I think the second version is much more logical considering what I am doing. Anyway, what is the "proper" way to do this?

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  • Inheritance - initialization problem

    - by dumbquestion
    I have a c++ class derived from a base class in a framework. The derived class doesn't have any data members because I need it to be freely convertible into a base class and back - the framework is responsible for loading and saving the objects and I can't change it. My derived class just has functions for accessing the data. But there are a couple of places where I need to store some temporary local variables to speed up access to data in the base class. mydata* MyClass::getData() { if ( !m_mydata ) { // set to NULL in the constructor m_mydata = some_long_and complex_operation_to_get_the_data_in_the_base() } return m_mydata; } The problem is if I just access the object by casting the base class pointer returned from the framework to MyClass* the ctor for MyClass is never called and m_mydata is junk. Is there a way of only initializing the m_mydata pointer once?

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  • MVC, how view should be accessed from controller?

    - by Kirzilla
    Hello, I'm just learning MVC so you could find my question rather strange... My Controller have access to different shared objects through Container object passed to Controller's constructor. To access shared objects I should do $this-container-db to access Database adapter or $this-container-memcache to access Memcached adapter. I want to know should I put View object into Container with shared objects or no? From one side it is really comfortable to take view from this container, but this way I couldn't create multiple Views instances (for example, every time I'm calling Controller's method from View I should have one more View instance). What is the solution? How should I pass View object into Controller and/or how should I create new View instances from Controller? Thank you!

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  • Can I add and remove elements of enumeration at runtime in Java

    - by Brabster
    It is possible to add and remove elements from an enum in Java at runtime? For example, could I read in the labels and constructor arguments of an enum from a file? @saua, it's just a question of whether it can be done out of interest really. I was hoping there'd be some neat way of altering the running bytecode, maybe using BCEL or something. I've also followed up with this question because I realised I wasn't totally sure when an enum should be used. I'm pretty convinced that the right answer would be to use a collection that ensured uniqueness instead of an enum if I want to be able to alter the contents safely at runtime.

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  • Hidden Features of Google Guice

    - by Jon
    Google Guice provides some great dependency injection features. I came across the @Nullable feature recently which allows you to mark constructor arguments as optional (permitting null) since Guice does not permit these by default: e.g. public Person(String firstName, String lastName, @Nullable Phone phone) { this.firstName = checkNotNull(firstName, "firstName"); this.lastName = checkNotNull(lastName, "lastName"); this.phone = phone; } http://code.google.com/p/google-guice/wiki/UseNullable What are the other useful features of Guice (particularly the less obvious ones) that people use?

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  • php class basic question

    - by Ross
    hi <?php class myClass { var $input; var $output; function myClass($input) { $output = 'You entered: ' . $input; return $output; } } $test = new myClass; echo $test->myClass(123); ?> this works, but returns this warning: Warning: Missing argument 1 for myClass::myClass() I read in to this, and seems that the constructor is expecting a value, so by adding: function myClass($input='') the warning is removed, but this seems so unnecessary? could someone enlighten me as to why it's required to define a value to prevent that warning? thanks for any pointers

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  • Can I use Linq to project a new typed datarow?

    - by itchi
    I currently have a csv file that I'm parsing with an example from here: http://alexreg.wordpress.com/2009/05/03/strongly-typed-csv-reader-in-c/ I then want to loop the records and insert them using a typed dataset xsd to an Oracle database. It's not that difficult, something like: foreach (var csvItem in csvfile) { DataSet.MYTABLEDataTable DT = new DataSet.MYTABLEDataTable(); DataSet.MYTABLERow row = DT.NewMYTABLERow(); row.FIELD1 = csvItem.FIELD1; row.FIELD2 = csvItem.FIELD2; } I was wondering how I would do something with LINQ projection: var test = from csvItem in csvfile select new MYTABLERow { FIELD1 = csvItem.FIELD1, FIELD2 = csvItem.FIELD2 } But I don't think I can create datarows like this without the use of a rowbuilder, or maybe a better constructor for the datarow?

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  • Getting list of fields back from 'use fields' pragma?

    - by makenai
    So I'm familiar with the use fields pragma in Perl that can be used to restrict the fields that are stored in a class: package Fruit; use fields qw( color shape taste ); sub new { my ( $class, $params ) = @_; my $self = fields::new( $class ) unless ref $class; foreach my $name ( keys %$params ) { $self->{ $name } = $params->{ $name }; } return $self; } My question is.. once I've declared the fields at the top, how I can get the list back.. say because I want to generate accessors dynamically? Is keys %FIELDS the only way? Secondarily, is there a more efficient way to pre-populate the fields in the constructor than looping through and assigning each parameter as I am above? Thanks!

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  • Typed DataSet connection - required to have one in the .xsd file?

    - by Kyralessa
    In the .xsd file for a typed DataSet in .NET, there's a <Connections> section that contains a list of any data connections I've used to set up the DataTables and TableAdapters. There are times when I'd prefer not to have those there. For instance, sometimes I prefer to pass in a connection string to a custom constructor and use that rather than look for one in settings, .config, etc. But it seems like if I remove the connection strings from that section (leaving it empty), or remove the section entirely, the DataSet code-generation tool freaks out. Whereas if I don't remove them, the DataSet gripes when I put it in a different project because it can't find the settings for those connection strings. Is there any way I can tell a typed DataSet not to worry about any connections? (Obviously I'll have to give it a connection if I change any TableAdapter SQL or stored procs, but that should be my problem.)

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  • how does serializable work in java?

    - by Karl Trumstedt
    If I have an instance of a class that I store in a session I need to make it serializable. This class has a static variable, will this be serialized in every instance stored? The static variable is a reference to a cache containing a lot of data in the background. Will all of this data be serialized? If so, it seems preferable to make this variable transient and re-fetch the cache instance each time the instance is restored. Maybe not store the cache instance at all in the class. Will the constructor execute when a class is restored from a serialized state? if not is there any other method I can use to re-instate a transient variable?

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  • Using pipes inside a class in C++

    - by Paul
    I'm trying to use this tutorial to make plots with Gnuplot in C++. However I will be using the pipe to Gnuplot from within a class, but then I run into some problems: I've got a header file where I declare all variables etc. I need to declare the pipe-variable here too, but how do I do that? I've tried doing it straight away, but it doesn't work: Logger.h: class Logger { FILE pipe; } Logger.cpp: Logger::Logger() { //Constructor *pipe = popen("gnuplot -persist","w"); } Gives the error Logger.cpp:28: error: no match for ‘operator=’ in ‘*((Logger*)this)->Logger::pipe = popen(((const char*)"gnuplot -persist"), ((const char*)"w"))’ Suggestions?

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  • Usage patterns/use cases for DI or when to start using it

    - by Fabian
    I'm not sure for which use cases one should to use DI in the application. I know that injecting services like PlaceService or CalculationService etc fits very well but should I also create my domain objects with DI like a User? What is if the User has only one constructor which requires a first and lastname. Is this solveable with DI? Should I use DI to create the instances for Set/List interfaces or is this pure overkill? I use guice primarily.

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  • Why baseclass calls method of subclass?

    - by twlkyao
    I encounter some code like the following: BaseClass: public class BaseClass { String name = "Base"; public BaseClass() { printName(); } public void printName() { System.out.println(name + "——Base"); } } DrivedClass: public class SubClass extends BaseClass { String name = "Sub"; public SubClass() { printName(); } public void printName() { System.out.println(name + "——Sub"); } public static void main(String[] args) { new SubClass(); } } When run the code, the output is: null——Sub Sub——Sub while it should be: Base——Base Sub——Sub I wonder why the BaseClass constructor calls the SubClass method, can anybody explain this? Thanks in advance.

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  • Do I really have to call Focus in OnMouseDown of my custom Control?

    - by Thomas
    I'm implementing a custom control that inherits from Control. I want it to be focusable (it's a kind of list box). In the constructor, I do SetStyle(ControlStyles.Selectable, true); I can now use Tab to navigate to the control. However, when the control receives a mouse click, it does not automatically claim focus. I can work around this, of course: protected override void OnMouseDown(MouseEventArgs e) { Focus(); base.OnMouseDown(e); } But this feels like a kludge that should not be necessary. Is this really the way to go? Or is there some way to tell Control to claim focus automatically when it receives a mouse click?

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  • List in a Python class shares the same object over 2 different instances?

    - by zfranciscus
    I created a class: class A: aList = [] now I have function that instantiate this class and add items into the aList. note: there are 2 items for item in items: a = A(); a.aList.append(item); I find that the first A and the second A object has the same number of items in their aList. I would expect that the first A object will have the first item in its list and the second A object will have the second item in its aList. Can anyone explain how this happens ? PS: I manage to solve this problem by moving the aList inside a constructor : def __init__(self): self.aList = []; but I am still curious about this behavior

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  • Bring Control to ToolBox

    - by Mohanavel
    I created a TextBoxControl which is inherited from Infragistics.Win.UltraWinEditors.UltraTextEditor, an Infragistics control. As showed below. public class TextBoxControl : Infragistics.Win.UltraWinEditors.UltraTextEditor { //My Stuff } At some level Infragistics.Win.UltraWinEditors.UltraTextEditor class also inherited from WinForm's "Control" class. My problem is, this control is not appearing in the ToolBox. I done two steps 1. Choose from browse option and select the dll where the class present 2. Drag and drop the dll directly to the ToolBox In-fact both are same, TextBoxControl control is not appearing in the ToolBox, what i missing here. Edit : TextBoxControl class have empty constructor, nothing special in this class.

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  • c++ Array passing dilemma

    - by Thomas
    Hi, I am writing a function that takes a string, string pointer and an int. The function splits the string based on a set of rules and puts each token into an array. I need to return the array out of the function with the number of elements in the int variable etc. I am stuck as to how I return the array as I can not use auto other wise it is destroyed and I am reluctant to use new as I feel this is patchy. I have other ideas on how to go about this but would like to see how other people go about this first. I could also be wrong and it could be possible to pass an auto out of an array. I can also not use vectors so there goes a copy constructor.

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  • C++ performance, optimizing compiler, empty function in .cpp

    - by Dodo
    I've a very basic class, name it Basic, used in nearly all other files in a bigger project. In some cases, there needs to be debug output, but in release mode, this should not be enabled and be a NOOP. Currently there is a define in the header, which switches a makro on or off, depending on the setting. So this is definetely a NOOP, when switched off. I'm wondering, if I have the following code, if a compiler (MSVS / gcc) is able to optimize out the function call, so that it is again a NOOP. (By doing that, the switch could be in the .cpp and switching will be much faster, compile/link time wise). --Header-- void printDebug(const Basic* p); class Basic { Basic() { simpleSetupCode; // this should be a NOOP in release, // but constructor could be inlined printDebug(this); } }; --Source-- // PRINT_DEBUG defined somewhere else or here #if PRINT_DEBUG void printDebug(const Basic* p) { // Lengthy debug print } #else void printDebug(const Basic* p) {} #endif

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  • Is it possible to create a jdbc connection without a password (using postgresql 'trust')?

    - by mojones
    I am using jdbc to connect to a postgresql database in a java application (actually the app is written in Groovy). I have postgresql set up to use the 'trust' authentication method. Is it possible to open a jdbc connection without specifying a password? When I try to use the normal constructor with a blank password, it fails with Exception in thread "Thread-2" org.postgresql.util.PSQLException: FATAL: password authentication failed for user "myuser" Even though, from the command line, this works fine psql -U myuser mydatabase Welcome to psql 8.3.5, the PostgreSQL interactive terminal. Type: \copyright for distribution terms \h for help with SQL commands \? for help with psql commands \g or terminate with semicolon to execute query \q to quit

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  • WPF UserControl event called only once?

    - by 742
    Hi Everyone, I need to bind two-way a property of a user control to a property of a containing user control. I also need to set a default value to the property from code in the child (cannot be done easily from XAML tags). If I call my code from the child constructor, the value is set in the parent but the change callback routine is not triggered (my understanding is that the parent doesn't yet exist at the time the child is created). My current workaround is to catch the Loaded event of the child and to call the code from the handler. Howver as Loaded is called more than once, I need to set a flag to set the property only the first time. I don't like this way, but I don't know if there is a single shot event that could be used, or if this can be done otherwise. Any feedback based on your experience?

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  • Objective C instance variables - Newbie

    - by Dwayne King
    OK - so I'm sure my confusion here is just a result of being stuck in a "Java mindset" and not understanding how Obj C differs in this case. In Java, I can declare a variable in a class, like this, and each instance of that class will have it's own: MyClass { String myVar; MyClass() { // constructor } } In Obj C I tried to do the same thing by declaring a variable only in the .m file like this: #import "MyClass.h" @implementation MyClass NSString *testVar; @end My expectation here was that this variable has a scope limited to this class. So I created a second class (identical): #import "MySecondClass.h" @implementation MySecondClass NSString *testVar; @end What I'm seeing (and has me baffled) is that changing the variable in one class, affects the value seen in the other class. In fact, if I set a breakpoint, and then "Jump to Definition" of the variable, it takes me to th I've created an extremely small XCode project that demonstrates the problem here Nothing more humbling than moving to a new language :) Thanks in advance.

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  • Calling a WCF WebService in PHP via wsHttpBinding.

    - by Justin Dearing
    I have a WCF webservice I can connect to it via basicHttp, but not wsHttp. I try to conenct to it via wshttp via the following: $service = new SoapClient ("http://service.companyname.local:6666/Service/?wsdl", array( "location" => "http://service.companyname.local:6666/Service/WCF", "trace" => true, 'soap_version' => SOAP_1_2 ) ); The call to the SoapClient constructor returns fine. When I try to call one using $client-FunctionName, the page just sits there loading for quite a while, and eventually returns the error "Error Fetching http headers". What exactly is this supposed to mean and how do I fix it? (Consuming the service from .Net client works perfectly.)

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