Search Results

Search found 17407 results on 697 pages for 'static constructor'.

Page 335/697 | < Previous Page | 331 332 333 334 335 336 337 338 339 340 341 342  | Next Page >

  • what is serialization and how it works

    - by Rozer
    I know the serialization process but have't implemented it. In my application i have seen there are various classes that has been implemented serilizable interface. consider following class public class DBAccessRequest implements Serializable { private ActiveRequest request = null; private Connection connection = null; private static Log log = LogFactory.getLog(DBAccessRequest.class); public DBAccessRequest(ActiveRequest request,Connection connection) { this.request = request; this.connection = connection; } /** * @return Returns the DB Connection object. */ public Connection getConnection() { return connection; } /** * @return Returns the active request object for the db connection. */ public ActiveRequest getRequest() { return request; } } just setting request and connection in constructor and having getter setter for them. so what is the use of serilizable implementation over here...

    Read the article

  • Avoid Flickering in Windows Forms?

    - by user1733909
    Double buffering not working with combo-box. is there any another methods to avoid flickering in windows forms? i have one windows form with number of panels in it. I'm showing only one panel at a time based on my menu selection. i have one icon panel,one header panel and the combo box. based on the selected item of that combo-box the gridview1 and 2 are filling. when I'm rapidly selecting the combo-box item using my keyboard down arrow the icon panel and the header panel are always repainting. i need to keep that both without any change. this two panels producing some flashing effect(ie,they are blinking or flashing) while I'm changing the combo box selected index. is there any way to avoid this flashing.? i tried double-buffered enabled in form constructor and form load event. Please Help..............

    Read the article

  • Cant append "used" DOMObject in IE

    - by Kein
    I have some objects, that keep created DOMObjects, like here: function category(){ var domBlock; this.block = function(){ if (!domBlock){ // Here dom-object constructor $('<div></div>'); etc } return domBlock; // jquery object, // but i test and native document.createElement } } Then i clear category's area, and append old and new received(with Ajax) objects: area.html(''); for(id in category_list){ area.append( category_list[id].block() ); } where category_list is list that contain category objects. Area is jQuery object. In other browsers (except IE) i get area with all needed categories, but in IE i get only new received categories(that just create DomObject), other old objects that keeped old DomObject not show. I know it possible make with innerHTML, but i wont keep DomObject, not text. Because DomObject keep many events. And it very hard for browser attach events for each DomObject after refresh area.

    Read the article

  • How to use SQLiteOpenHelper without or less restrictive use of Context?

    - by Pentium10
    If you extend SQLiteOpenHelper, for the Constructor you have to use a Context. I am wondering if there is a way to leave this out, and be able to work with database tables without a Context. Or at least be least restrictive, I mean a way of project/class structure that will make history the several context passings I have to do now. As it is my application has several level of classes, chained in each other, and there are a few that connects to the database, but have no whatsoever influence on the interface, so they don't actually need the Context. Are you creating your classes in the way that you pass each time a Context to them? If not, how you do, how you reuse a Context in a short class?

    Read the article

  • How to make TObjectDictionary.Values accessible as property?

    - by Holgerwa
    I have an object like this: TMyObj = class private FObjList: TObjectDictionary <integer, TMyObject>; public constructor Create; destructor Destroy; // How to access Values correctly? Something similar to this not working code property Values: TValueCollection read FObjList.Values write FObjList.Values; end; var MyObj: TMyObj; To access the values of FObjList, I'd like to write: for tmpObject in MyObj.Values do ... How do I need to declare the property "Values" so that MyObj.Values behaves exactly as if I would access MyObj.FObjList.Values?

    Read the article

  • 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?

    Read the article

  • Syncing JS+PHP time

    - by meder
    Since the Date constructor is based on your PC's timezone and server-side is obviously dependent on the server's time settings... What procedures can I do to ensure that the timestamps I generate are consistent on both ends? I have a jQuery datepicker setup and I do a lot of work, I also have my own datepicker that's generated from server-side code which looks up db availability for bookings. I'm saving arrival/departure times on the server-side and the days are off by one because the JS is local timezone ( mine is Eastern ) . Is my only option doing something like making the JS call PHP to grab a timestamp?

    Read the article

  • Why would a 'public event EventHandler cccc' be null?

    - by Matt
    Why would a 'public event EventHandler cccc' be null? I have a class that's public class Builder { public event EventHandler StartedWorking; public Builder() { // Constructor does some stuff } public void Start() { StartedWorking(this, eventargobject); //StartedWorking is null -- } } This seems straightforward and something I do all the time? Am I missing something obvious or is there something that could cause this? EDIT: Does this mean that if I fire an event that is not subscribed to in a client class I have to check that it is not null? EDIT-2: I guess I'd never had events that were never not subscribed to and hence never ran into this -- You learn something new every day Sorry about the seemingly stupid question....

    Read the article

  • passing parameters to a thread

    - by assassin
    I want to pass a function that takes a parameter to the ThreadStart Constructor in C#. But, it seems that this is not possible, as I get a syntax error it I try to do something like this Thread t1 = new Thread(new Thread Start(func1(obj1)); where obj1 is an object of type List<string> (say). If I want a thread to execute this function that takes in an object as a parameter, and I plan to create 2 such threads simultaneously with different parameter values what is the best method to achieve this?

    Read the article

  • Change a registry value in vb.net

    - by mhofer
    Hello, I have searched a lot to find a solution for my problem, but I can't find any specific solution. I need to change a value which is stored under HKEY_LOCAL_MACHINE\SOFTWARE\APP_NAME. It is not possible to use .NET's registry functions, since they have drastic restrictions. The following snippet should solve my problem: Dim regKey As RegistryKey Dim ver As Decimal regKey = My.Computer.Registry.LocalMachine.OpenSubKey("HKEY_LOCAL_MACHINE\SOFTWARE\APP_NAME", True) regKey.SetValue("IP", "192.168.10.15:18500") regKey.Close() Unfortunately, I get a NullReferenceExeption when I try to set the value. What should I do? I have imported Microsoft.Win32 and RegistryKey doesn't accept any constructor... cheers mike

    Read the article

  • Copy method optimization in compilers

    - by Dženan
    Hi All! I have the following code: void Stack::operator =(Stack &rhs) { //do the actual copying } Stack::Stack(Stack &rhs) //copy-constructor { top=NULL; //initialize this as an empty stack (which it is) *this=rhs; //invoke assignment operator } Stack& Stack::CopyStack() { return *this; //this statement will invoke copy contructor } It is being used like this: unsigned Stack::count() { unsigned c=0; Stack copy=CopyStack(); while (!copy.empty()) { copy.pop(); c++; } return c; } Removing reference symbol from declaration of CopyStack (returning a copy instead of reference) makes no difference in visual studio 2008 (with respect to number of times copying is invoked). I guess it gets optimized away - normally it should first make a copy for the return value, then call assignment operator once more to assign it to variable sc. What is your experience with this sort of optimization in different compilers? Regards, Dženan

    Read the article

  • [Qt] How to make another window pop up that extends QWidget as opposed to QDialog?

    - by Graphics Noob
    So far I've only had my main window pop up other windows that were QDialogs and I'm not getting it to work with a QWidget. The other window I want to display was designed with the Form Editor, then wrapped in a class called ResultViewer which extends QWidget (as opposed to QDialog). What I want is to have the ResultViewer show its ui in a seperate window. Now when I try to display it the ResultViewer ui just pops up in the main window on top of the mainwindow ui. The code I'm using to display it is this (in my mainwindow.cpp file) ResultViewer * rv = new ResultView(this); rv->show(); The constructor for the ResultViewer looks like this ResultViewer::ResultViewer(QWidget * parent) : QWidget(parent), ui(new Ui::ResultViewer) { ui->setupUi(this); } I've looked through the QWidget documentation a bit but the only thing I can find that may be related is the QWidget::window() function, but the explanation isn't very clear, it just gives an example of changing the title of a window.

    Read the article

  • Java - Does null variable require space in memory

    - by Yatendra Goel
    class CheckStore { private String displayText; private boolean state; private String meaningfulText; private URL url; public CheckStore(String text, boolean state) { this.displayText = text; this.state = state; } : : } As I am initializing only two variables (displayText and state) in the constructor, Will the rest two variables (meaningfulText and url which will have the value null) will require space in memory to store null value. Q1. I think they will require space. If they will, then how much memory does a null value takes in the memory (like int takes 4 bytes). Q2. How much space a string takes in memory. I guess it will depend on the length of the string. So how much space a string takes of how much length?

    Read the article

  • C# ToolTip will not re-appear after first use.

    - by Roberto Sebestyen
    I have a Forms C# application where I would like to use a toolTip on one of the text boxes. I Initialize the tool-tip in the constructor of the Form class, and it works the first time. So when I hover over the text box with my mouse it works, but once the toolTip times out and it goes away, it does not re-appear when I move my mouse away and back onto the control. I would expect it to come back and I'm wondering what I'm doing wrong. Here is how I initialize the tooltip: myTip = new ToolTip(); myTip.ToolTipIcon = ToolTipIcon.Info; myTip.IsBalloon = true; myTip.ShowAlways = true; myTip.SetToolTip(txtMyTextBox,"My Tooltip Text");

    Read the article

  • JavaScript constructors inside a namespace

    - by Joe
    I have read that creating a namespace for JavaScript projects helps to reduce conflicts with other libraries. I have some code with a lot of different types of objects for which I have defined constructor functions. Is it good practice to put these inside the namespace as well? For example: var shapes = { Rectangle: function(w, h) { this.width = w; this.height = h; } }; which can be called via: var square = new shapes.Rectangle(10,10);

    Read the article

  • Confusion using MYSQLI

    - by user1020069
    I just started using mysqli API for PHP. Apparently, every time an object of the class MYSQLI is instantiated, it can setup a connection to the database as it connects to the server unlike mysql_connect, which connects to the server first and then you are required to specify the database to query. Now this is a good problem if the db exists, in my case, the db does not exist on the first ever connection to the server/execution of the problem, hence I must connect without specifying the database, which is fine, since the msyqli constructor does not make this database mandatory. My challenge is essentially, how do I check if the database exists before attempting the first connection. The only way to really do this would be to establish a conection to the server and then use the result of the following query to gauge if the database exists: SELECT COUNT(*) AS `exists` FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMATA.SCHEMA_NAME="dbname" ; If this returns true, then the database exists, but now the challenge is how do I get the mysqli object to query this database rather than having to prefix the name of the database in the query. Thanks much

    Read the article

  • testing existing attribute of a @classmethod function, yields AttributeError

    - by alex
    i have a function which is a class method, and i want to test a attribute of the class which may or may not be None, but will exist always. class classA(): def __init__(self, var1, var2 = None): self.attribute1 = var1 self.attribute2 = var2 @classmethod def func(self,x): if self.attribute2 is None: do something i get the error AttributeError: class classA has no attribute 'attributeB' when i access the attribute like i showed but if on command line i can see it works, x = classA() x.attributeB is None True so the test works. if i remove the @classmethod decorator from func, the problem disapears. if i leave the @classmethod decorator, it only seems to affect variables which are supplied default values in the super-class's constructor. whats going on in the above code?

    Read the article

  • Explicitly persist states in Workflow 4.0 rather than everything.

    - by jlafay
    I have ran into an issue with my SQL instance store attached to a WorkflowApplication that is running. When I exit my application I'm calling an Unload() on the WF app to persist it. I didn't think about it during design time, but it does makes sense, it's persisting an arg that was passed in to the WorkflowApplication constructor when instanced. When the application runs, everything in the workflow works as expected. When I call Unload() I get an unhandled exception that states that the arg is not serializable and needs [DataContractAttribute]. What's passed into the workflow is my applications custom logger object that I wrote so that the WF can log to disk in a uniform way that I prefer. How do I prevent the workflow app from persisting this one argument and persist everything else? I'm sure something can be done with extensions but I'm having a hard time finding info on them or finding persistence examples for my scenario.

    Read the article

  • Can I use MFC objects in STL containers?

    - by Jesse Stimpson
    The following code doesn't compile for me in MSVC2005: std::vector<CMenu> vec(10); CMenu is an MFC menu object (such as a context menu). Through some testing I learned that CMenu does not have a public copy constructor. To do what I wanted to do, I needed to use a dynamic array. CMenu* menus = new CMenu[10]; // ... delete [] menus; Of course, now I've lost all the benefits of using an STL container. Do I have any other options?

    Read the article

  • Qt "no matching function for call"

    - by Blin
    I have no matching function for call to 'saveLine::saveLine()' error when compiling my application. The construcor is never actually called. saveLine class definition: class saveLine { public: saveLine(QWidget *parent); private: QPushButton *selectButton, *acceptButton; QLabel *filePath; QLineEdit *allias; }; saveLine is used in another class which is defined as follows: class MWindow : public QWidget { Q_OBJECT public: MWindow(QWidget *parent=0); private: saveLine line1; }; error points to MWindow constructor implementation MWindow::MWindow(QWidget *parent):QWidget(parent) { this->setWindowTitle("Launcher"); this->resize(600,600); } What should i do? I intend to use saveLine class in a vector, to create lines at runtime.

    Read the article

  • C++ enum casting and templates

    - by JP
    I get the following error with VS2008: Conversion to enumeration type requires an explicit cast (static_cast, C-style cast or function-style cast) When casting a down casting a ClassA to ClassA_1 and ClassA_1 is a templated class that received an enum for parameter such as: ClassA { virtual ~ClassA(){}; } template <class Param1> ClassA_1 : public ClassA { public: //constructor ClassA_1(Param1 p1) { _p1 = p1; } Param1 _p1; } So I have a upcasted ClassA a = new ClassA_1<myenum>(); When I need to do this: ClassA_1<myenum> a1 = (ClassA_1<myenum> a); // This fails ... The only way it works is: ClassA_1<int> a1 = (ClassA_1<int> a); but this break my template as it must always deal with int... How to properly cast a enum that is now a int, back into the enum?

    Read the article

  • Is it a bad idea to create tests that rely on each other within a test fixture?

    - by nbolton
    For example: // NUnit-like pseudo code (within a TestFixture) Ctor() { m_globalVar = getFoo(); } [Test] Create() { a(m_globalVar) } [Test] Delete() { // depends on Create being run b(m_globalVar) } … or… // NUnit-like pseudo code (within a TestFixture) [Test] CreateAndDelete() { Foo foo = getFoo(); a(foo); // depends on Create being run b(foo); } … I’m going with the later, and assuming that the answer to my question is: No, at least not with NUnit, because according to the NUnit manual: The constructor should not have any side effects, since NUnit may construct the class multiple times in the course of a session. ... also, can I assume it's bad practice in general? Since tests can usually be run separately. So the result of Create may never be cleaned up by Delete.

    Read the article

  • OBject access from different functions in VC++

    - by sijith
    Hi, I have 3 function in my class B. These three function have to access member function of other class A. I did this by creating object of class A in class B constructor and tried to access that object in functions of class B. But its showing error. How can i assess the same object in these three functions. Where i have to create object of class A B::B() { A a; } B:: function() { a.fun(); //fun belongs to class A } B:: function1() { a.fun1(); //fun1 belongs to class A } I am getting error, How can i implement the same where i can access object a in both function.

    Read the article

  • Passing Services to MainViewModel - SHOULD I use a dependency injection container ?

    - by msfanboy
    Hello, I have this code: public partial class App : Application { protected override void OnStartup(StartupEventArgs e) { base.OnStartup(e); var mainVM = new MainViewModel ( new Service1(), ... new Service10(), ); var window = new MainWindow(); window.DataContext = mainVM; window.Show(); } } I pass all my Services instances to the MainViewModel. Within the MainViewModel I spread those services to other ViewModels via constructor parameter passing. Should I use any DI framework for the services in the App class? If yes whats the benefit of resolving the services instead of just creating the instance manually... ?

    Read the article

  • Why is there "data" and "newtype" in Haskell?

    - by martingw
    To me it seems that a newtype definition is just a data definition that obeys some restrictions (only one constructor and such), and that due to these restrictions the runtime system can handle newtypes more efficiently. Ok, and the handling of pattern matching for undefined values is slightly different. But suppose Haskell would only knew data definitions, no newtypes: Couldn't the compiler find out for himself whether a given data definition obeys these restrictions, and automatically treat it more efficiently? I'm sure I'm missing out on something, these Haskell designers are so clever, there must be some deeper reason for this...

    Read the article

< Previous Page | 331 332 333 334 335 336 337 338 339 340 341 342  | Next Page >