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  • New to C# and trying to use a global variable

    - by Andrew G. Johnson
    Is it possible to use global variables in C#? I'm coming from mainly a PHP background so variables are either accessible everywhere or just a global definition away. My main issue is I have a User class that I built myself to wrap around the current users table on my company's database. I am defining it in the MasterPage but can't seem to access it from the actual pages (I don't know if there's a better word to describe them but they are the pages that inherit the styles and format from the MasterPage) Any general tips or implementation practices for me? EDIT: here's some code snippets of what I'm trying to do: Site.master.cs public partial class SiteMaster : System.Web.UI.MasterPage { public User user = new User(); } logout.aspx <%@ Page Title="" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeFile="logout.aspx.cs" Inherits="logout" %> <%@ MasterType virtualPath="~/Site.master"%> logout.aspx.cs public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { User user = Master.user; } }

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  • How to declare a generic constraint that is a generic type

    - by HackedByChinese
    I have a two generic abstract types: Entity and Association. Let's say Entity looks like this: public class Entity<TId> { //... } and Association looks like this: public class Association<TEntity, TEntity2> { //... } How do I constrain Association so they can be of any Entity? I can accomplish it by the following: public class Association<TEntity, TId, TEntity2, TId2> where TEntity : Entity<TId> where TEntity2: Entity<TId2> { //... } This gets very tedious as more types derive from Association, because I have to keep passing down TId and TId2. Is there a simpler way to do this, besides just removing the constraint?

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  • Giving 'TemplateError' can't convert String into Integer

    - by Gagan
    Hi, I recently transfered my app from Rails2 to Rails3. The code in 'app/views/distribution/index.html.erb' is like :- <div style="padding-bottom:10px; padding-left:0px;float:left;display:<%= (!session[:album][@artist.id.to_s].empty? && !session[:album][@artist.id.to_s].nil?)?'block' : 'none' %>" id = "make_payment_enabled"> <%= link_to 'Make Payments',{:action => 'pay', :album=>@album.id}, :class => "button" %> </div> It's giving me TemplateError on line :- <div style="padding-bottom:10px; padding-left:0px;float:left;display:<%= (!session[:album][@artist.id.to_s].empty? && !session[:album][@artist.id.to_s].nil?)?'block' : 'none' %>" id = "make_payment_enabled"> How to resolve the problem ?

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  • Sending an array of complex objects in the get string in C# ASP.NET MVC

    - by Mr Snuffle
    Hi, I want to send an array of objects in the get request string. I know this isn't the optimal solution, but I really just want to get this up and running. If I have a class, something like this public class Data { public int a { get; set; } public int b { get; set; } } public class RequestViewData { public IList<Data> MyData { get; set; } } I thought I could bind the MVC route to a web request like this http://localhost:8080/Request?MyData[0].a=1&MyData[0].b=2&MyData[1].a=3&[MyData[1].b=4 But all this does is create an array of two data objects without populating the values 1,2, 3 or 4. Is there a way to bind complex objects arrays?

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  • Android: Using MediaRecorder to crop an existing audio file?

    - by user141146
    Hi, I'd like to take an existing mp3 file located on an SD card and arbitrarily crop it (e.g. crop from 0:12 to 1:14 in a 3 minute song). The only class that I've seen that seems remotely relevant to do this is the MediaRecorder class. My 'hope' would be to "record" an existing file like this: MediaRecorder recorder = new MediaRecorder(); recorder.setAudioSource(###some magical way of specifying an existing file??###); But this obviously doesn't work (setAudioSource() takes an int and seems to default to the phone's microphone). Is there a class or an approach that can be used to crop audio on the phone itself? TKS!!

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  • Find all paths from root to leaves of tree in Scheme

    - by grifaton
    Given a tree, I want to find the paths from the root to each leaf. So, for this tree: D / B / \ A E \ C-F-G has the following paths from root (A) to leaves (D, E, G): (A B D), (A B E), (A C F G) If I represent the tree above as (A (B D E) (C (F G))) then the function g does the trick: (define (g tree) (cond ((empty? tree) '()) ((pair? tree) (map (lambda (path) (if (pair? path) (cons (car tree) path) (cons (car tree) (list path)))) (map2 g (cdr tree)))) (else (list tree)))) (define (map2 fn lst) (if (empty? lst) '() (append (fn (car lst)) (map2 fn (cdr lst))))) But this looks all wrong. I've not had to do this kind of thinking for a while, but I feel there should be a neater way of doing it. Any ideas for a better solution (in any language) would be appreciated.

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  • 'Lexical' scoping of type parameters in C#

    - by leppie
    I have 2 scenarios. This fails: class F<X> { public X X { get; set; } } error CS0102: The type 'F' already contains a definition for 'X' This works: class F<X> { class G { public X X { get; set; } } } The only logical explanation is that in the second snippet the type parameter X is out of scope, which is not true... Why should a type parameter affect my definitions in a type? IMO, for consistency, either both should work or neither should work. Any other ideas? PS: I call it 'lexical', but it probably is not not the correct term.

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  • C++0x rvalue references - lvalues-rvalue binding

    - by Doug
    This is a follow-on question to http://stackoverflow.com/questions/2748866/c0x-rvalue-references-and-temporaries In the previous question, I asked how this code should work: void f(const std::string &); //less efficient void f(std::string &&); //more efficient void g(const char * arg) { f(arg); } It seems that the move overload should probably be called because of the implicit temporary, and this happens in GCC but not MSVC (or the EDG front-end used in MSVC's Intellisense). What about this code? void f(std::string &&); //NB: No const string & overload supplied void g1(const char * arg) { f(arg); } void g2(const std::string & arg) { f(arg); } It seems that, based on the answers to my previous question that function g1 is legal (and is accepted by GCC 4.3-4.5, but not by MSVC). However, GCC and MSVC both reject g2 because of clause 13.3.3.1.4/3, which prohibits lvalues from binding to rvalue ref arguments. I understand the rationale behind this - it is explained in N2831 "Fixing a safety problem with rvalue references". I also think that GCC is probably implementing this clause as intended by the authors of that paper, because the original patch to GCC was written by one of the authors (Doug Gregor). However, I don't this is quite intuitive. To me, (a) a const string & is conceptually closer to a string && than a const char *, and (b) the compiler could create a temporary string in g2, as if it were written like this: void g2(const std::string & arg) { f(std::string(arg)); } Indeed, sometimes the copy constructor is considered to be an implicit conversion operator. Syntactically, this is suggested by the form of a copy constructor, and the standard even mentions this specifically in clause 13.3.3.1.2/4, where the copy constructor for derived-base conversions is given a higher conversion rank than other implicit conversions: A conversion of an expression of class type to the same class type is given Exact Match rank, and a conversion of an expression of class type to a base class of that type is given Conversion rank, in spite of the fact that a copy/move constructor (i.e., a user-defined conversion function) is called for those cases. (I assume this is used when passing a derived class to a function like void h(Base), which takes a base class by value.) Motivation My motivation for asking this is something like the question asked in http://stackoverflow.com/questions/2696156/how-to-reduce-redundant-code-when-adding-new-c0x-rvalue-reference-operator-over ("How to reduce redundant code when adding new c++0x rvalue reference operator overloads"). If you have a function that accepts a number of potentially-moveable arguments, and would move them if it can (e.g. a factory function/constructor: Object create_object(string, vector<string>, string) or the like), and want to move or copy each argument as appropriate, you quickly start writing a lot of code. If the argument types are movable, then one could just write one version that accepts the arguments by value, as above. But if the arguments are (legacy) non-movable-but-swappable classes a la C++03, and you can't change them, then writing rvalue reference overloads is more efficient. So if lvalues did bind to rvalues via an implicit copy, then you could write just one overload like create_object(legacy_string &&, legacy_vector<legacy_string> &&, legacy_string &&) and it would more or less work like providing all the combinations of rvalue/lvalue reference overloads - actual arguments that were lvalues would get copied and then bound to the arguments, actual arguments that were rvalues would get directly bound. Questions My questions are then: Is this a valid interpretation of the standard? It seems that it's not the conventional or intended one, at any rate. Does it make intuitive sense? Is there a problem with this idea that I"m not seeing? It seems like you could get copies being quietly created when that's not exactly expected, but that's the status quo in places in C++03 anyway. Also, it would make some overloads viable when they're currently not, but I don't see it being a problem in practice. Is this a significant enough improvement that it would be worth making e.g. an experimental patch for GCC?

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  • Overriding constructors

    - by demas
    Here is sample code: class One def initialize(*args) case args.size when 0 puts "one initialize" when 1 puts "one initialize #{args[0]}" end end end class Two def initialize(*args) if args.size == 2 then puts "two initialize #{args[0]} and #{args[1]}" else super(args) end end end one = One.new one = One.new("thing") two = Two.new("some", "other") two = Two.new("some") Now I'm launching the code and getting the error message: [[email protected]][~/temp]% ruby test2.rb one initialize one initialize thing two initialize some and other test2.rb:17:in `initialize': wrong number of arguments(1 for 0) (ArgumentError) from test2.rb:17:in `initialize' from test2.rb:26:in `new' from test2.rb:26:in `<main>' How can I call parent's constructor from class Two ?

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  • NoClassDefFound error - Spring JDBC

    - by glowcoder
    Right now, I'm compiling my .class files in eclipse and moving them over to my %tomcat_home%\webapps\myapp\WEB-INF\classes directory. They compile just fine. I also have in the ...\classes directory a org.springframework.jdbc-3.0.2.RELEASE.jar which I have verified has the org.springframework.jdbc.datasource.DriverManagerDataSource class inside it. However, I get a NoClassDefFound error when I run my class and it tries to DriverManagerDataSource source = new DriverManagerDataSource(); I don't understand why it wouldn't be finding that jar. Any help is appreciated!

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  • What can cause a double page request?

    - by johnnietheblack
    I am currently investigating a double request problem on my site. Not all the time, but sometimes, a requested page will in fact load twice...which is not a problem really until it is on a page with PHP that inserts stuff into my db on request (my tracking script). I have read that an empty src in an image tag, and an empty url() in a css background could potentially cause the page to be requested twice. However, I can't find any problems with those. Is there anything else that could be causing something like this?

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  • How to better design it ???

    - by Deepak
    public interface IBasePresenter { } public interface IJobViewPresenter : IBasePresenter { } public interface IActivityViewPresenter : IBasePresenter { } public class BaseView { public IBasePresenter Presenter { get; set; } } public class JobView : BaseView { public IJobViewPresenter JobViewPresenter { get { this.Presenter as IJobViewPresenter;} } } public class ActivityView : BaseView { public IActivityViewPresenter ActivityViewPresenter { get { this.Presenter as IActivityViewPresenter;} } } Lets assume that I need a IBasePresenter property on BaseView. Now this property is inherited by JobView and ActivityView but if I need reference to IJobViewPresenter object in these derived classes then I need to type cast IBasePresenter property to IJobViewPresenter or IActivityPresenter (which I want to avoid) or create JobViewPresenter and ActivityViewPresenter on derived classes (as shown above). I want to avoid type casting in derived classes and still have reference to IJobViewPresenter or IActivityViewPresenter and still have IBasePresenter in BaseView. Is there a way I can achieve it ?

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  • Strategies for generating Zend Cache Keys

    - by emeraldjava
    ATM i'm manually generating a cache key based on the method name and parameters, then follow to the normal cache pattern. This is all done in the Controller and i'm calling a model class that 'extends Zend_Db_Table_Abstract'. public function indexAction() { $cache = Zend_Registry::get('cache'); $individualleaguekey = sprintf("getIndividualLeague_%d_%s",$leagueid,$division->code); if(!$leaguetable = $cache->load($individualleaguekey)) { $table = new Model_DbTable_Raceresult(); $leaguetable = $table->getIndividualLeague($leagueid,$division,$races); $cache->save($leaguetable, $individualleaguekey); } $this->view->leaguetable = $leaguetable; .... I want to avoid the duplication of parameters to the cache creation method and also to the model method, so i'm thinking of moving the caching logic away from my controller class and into model class packaged in './model/DbTable', but this seems incorrect since the DB model should only handle SQL operations. Any suggestions on how i can implement a clean patterned solution?

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  • Is multi-level polymorphism possible in SQLAlchemy?

    - by Jace
    Is it possible to have multi-level polymorphism in SQLAlchemy? Here's an example: class Entity(Base): __tablename__ = 'entities' id = Column(Integer, primary_key=True) created_at = Column(DateTime, default=datetime.utcnow, nullable=False) entity_type = Column(Unicode(20), nullable=False) __mapper_args__ = {'polymorphic_on': entity_type} class File(Entity): __tablename__ = 'files' id = Column(None, ForeignKey('entities.id'), primary_key=True) filepath = Column(Unicode(255), nullable=False) file_type = Column(Unicode(20), nullable=False) __mapper_args__ = {'polymorphic_identity': u'file', 'polymorphic_on': file_type) class Image(File): __mapper_args__ = {'polymorphic_identity': u'image'} __tablename__ = 'images' id = Column(None, ForeignKey('files.id'), primary_key=True) width = Column(Integer) height = Column(Integer) When I call Base.metadata.create_all(), SQLAlchemy raises the following error: NotImplementedError: Can't generate DDL for the null type IntegrityError: (IntegrityError) entities.entity_type may not be NULL. This error goes away if I remove the Image model and the polymorphic_on key in File. What gives? (Edited: the exception raised was wrong.)

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  • Search resetting selection in tableview

    - by Jay
    I've got an NSTableView bound to an NSArrayController via content and selection indexes. All great so far - content displayed, etc. Now an NSSearchField is bound to the array controller via filterPredicate and the property of the array content instances that's to be searched. Searching/filtering the table view works great; table view showing only matching entries. However, searching resets the selection on the NSTableView if the existing selection isn't in the search results. Worse, not only during the search but after ending the search there's no selection on the table view. The NSArrayController is set up to Avoid Empty Selection. Any hints on how to properly configure bindings in this scenario to really prevent an empty selection much appreciated!

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  • JAXB Customizations and List<Object>

    - by DaUltimateTrooper
    Hi everybody. I used JAXB to create some classes from an XSD. The result was not quite what I expected and most probably it can be customized. It created a generic list instead of 3 different lists. Can this be corrected somehow? @XmlElements({ @XmlElement(name = "M1", type = M1_Type.class), @XmlElement(name = "M2", type = M2_Type.class), @XmlElement(name = "M3", type = M3_Type.class) }) protected List<Object> m1Orm2OrM3; Is there a customization to fix this?

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  • Using a delegate to populate a listbox

    - by Leroy Jenkins
    Ive been playing around with delegates trying to learn and I ran into one small problem Im hoping you can help me with. class myClass { OtherClass otherClass = new OtherClass(); // Needs Parameter otherClass.SendSomeText(myString); } class OtherClass { public delegate void TextToBox(string s); TextToBox textToBox; public OtherClass(TextToBox ttb) // ***Problem*** { textToBox = ttb; } public void SendSomeText(string foo) { textToBox(foo); } } the form: public partial class MainForm : Form { OtherClass otherClass; public MainForm() { InitializeComponent(); otherClass = new OtherClass(this.TextToBox); } public void TextToBox(string aString) { listBox1.Items.Add(aString); } } Obviously this doesnt compile because the OtherClass constructor is looking for TextToBox as a parameter. How would you recommend getting around the issue so I can get an object from myClass into the textbox in the form?

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  • Generic extension method returning IEnumerable<T> without using reflection

    - by roosteronacid
    Consider this snippet of code: public static class MatchCollectionExtensions { public static IEnumerable<T> AsEnumerable<T>(this MatchCollection mc) { return new T[mc.Count]; } } And this class: public class Ingredient { public String Name { get; set; } } Is there any way to magically transform a MatchCollection object to a collection of Ingredient? The use-case would look something like this: var matches = new Regex("([a-z])+,?").Matches("tomato,potato,carrot"); var ingredients = matches.AsEnumerable<Ingredient>();

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  • Calling a method with getattr in Python

    - by brain_damage
    How to call a method using getattr? I want to create a metaclass, which can call non-existing methods of some other class that start with the word 'oposite_'. The method should have the same number of arguments, but to return the opposite result. def oposite(func): return lambda s, *args, **kw: not oposite(s, *args, **kw) class Negate(type): def __getattr__(self, name): if name.startswith('oposite_'): return oposite(self.__getattr__(name[8:])) def __init__(self,*args,**kwargs): self.__getattr__ = Negate.__getattr__ class P(metaclass=Negate): def yep(self): return True But the problem is that self.__getattr__(sth) returns a NoneType object. >>> p = P() >>> p.oposite_yep() Traceback (most recent call last): File "<pyshell#115>", line 1, in <module> p.oposite_yep() TypeError: <lambda>() takes at least 1 positional argument (0 given) How to deal with this?

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  • Grails: Querying Associations causes groovy.lang.MissingMethodException

    - by Paul
    Hi, I've got an issue with Grails where I have a test app with: class Artist { static constraints = { name() } static hasMany = [albums:Album] String name } class Album { static constraints = { name() } static hasMany = [ tracks : Track ] static belongsTo = [artist: Artist] String name } class Track { static constraints = { name() lyrics(nullable: true) } Lyrics lyrics static belongsTo = [album: Album] String name } The following query (and a more advanced, nested association query) works in the Grails Console but fails with a groovy.lang.MissingMethodException when running the app with 'run-app': def albumCriteria = tunehub.Album.createCriteria() def albumResults = albumCriteria.list { like("name", receivedAlbum) artist { like("name", receivedArtist) } // Fails here maxResults(1) } Stacktrace: groovy.lang.MissingMethodException: No signature of method: java.lang.String.call() is applicable for argument types: (tunehub.LyricsService$_getLyrics_closure1_closure2) values: [tunehub.LyricsService$_getLyrics_closure1_closure2@604106] Possible solutions: wait(), any(), wait(long), each(groovy.lang.Closure), any(groovy.lang.Closure), trim() at tunehub.LyricsService$_getLyrics_closure1.doCall(LyricsService.groovy:61) at tunehub.LyricsService$_getLyrics_closure1.doCall(LyricsService.groovy) (...truncated...) Any pointers?

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  • Anyone using ASP.NET MembershipProvider with Nhibernate?

    - by JLago
    Hi, I'm trying to implement Membership controls in a mvc 2 application and i'm having trouble dealing with the MembershipUser class. I have my own data store (in Postgresql) and I'm using Nhibernate to deal with it from C#. The thing is, I have my own user class, but I can't use it with any provider I found that implements Membership, because all the functions return the predefined MembershipUser class and cannot return my own. I'm losing my mind here, is there any way i can work with this, or should I implement everything myself? thanks in advance!

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  • Returning a collection of objects from a webmethod

    - by Narmatha Balasundaram
    How do I return a collection of objects from a webmethod? And can this collection of objects be of different types - say of these 3 classes, private class ClassA { int A1; int A2; } private class ClassB { int B1; } private class ClassC { int C1; } ClassA objA = new ClassA(...); ClassB objB = new ClassB(...); ClassC objC = new ClassC(...); How can I return the objects, objA, objB and objC from a method?

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  • Does a C++ destructor always or only sometimes call data member destructors?

    - by Magnus
    I'm trying to validate my understanding of C++ destructors. I've read many times that C++ supplies a default destructor if I don't write one myself. But does this mean that if I DO write a destructor that the compiler WON'T still provide the default cleanup of stack-allocated class fields? My hunch is that the only sane behavior would be that all class fields are destroyed no matter what, whether I provide my own destructor or not. In which case the statement I've read so many times is actually a little misleading and could be better stated as: "Whether or not you write your own destructor, the C++ compiler always writes a default destructor-like sequence to deallocate the member variables of your class. You may then specify additional deallocations or other tasks as needed by defining your own destructor" Is this correct?

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  • Force external function to be const

    - by vanna
    Here is my problem. I made a class with a member function declared as const that uses an external function that I cannot modify (declared in someone else's code) and that is not declared const. More precisely Someone else's code class B { public: void foo(); }; My code class A : public B { public: void bar() const { this->foo(); } }; I know that for member data we can force const-correctness by using mutable or const_cast. How can I 'hack' foo such that my compiler understands that I would like to use it as if it was const even if it is not declared in someone else's code ?

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  • Remapping design issue

    - by Sirupsen
    Hello, I'm currently developing a Ruby Gem and I'm a bit lost on the design currently. Basically, I'm remapping some APIs, so my skeleton is something like this: module MyApp module SomeApi class Function > Base::Function ... end class Function2 > Base::Function2 ... end ... end module SomeApi2 ... end class RemappedFunction def initalize # set some values and stuf ... end def remapped_method # Problem: # How would I know, if I should take contact to # SomeApi, or SomeApi2? end end def interact_with(api) # What would be the best way of letting RemappedFunction # know which API to use? end end someapi2 = MyApp.interact_with(:someapi2) someapi2.remapped_method Any ideas?

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