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  • What is the best way to store static data in C# that will never changes

    - by Luke101
    I have a class that stores data in asp.net c# application that never changes. I really don't want to put this data in the database - I would like it to stay in the application. Here is my way to store data in the application: public class PostVoteTypeFunctions { private List<PostVoteType> postVotes = new List<PostVoteType>(); public PostVoteTypeFunctions() { PostVoteType upvote = new PostVoteType(); upvote.ID = 0; upvote.Name = "UpVote"; upvote.PointValue = PostVotePointValue.UpVote; postVotes.Add(upvote); PostVoteType downvote = new PostVoteType(); downvote.ID = 1; downvote.Name = "DownVote"; downvote.PointValue = PostVotePointValue.DownVote; postVotes.Add(downvote); PostVoteType selectanswer = new PostVoteType(); selectanswer.ID = 2; selectanswer.Name = "SelectAnswer"; selectanswer.PointValue = PostVotePointValue.SelectAnswer; postVotes.Add(selectanswer); PostVoteType favorite = new PostVoteType(); favorite.ID = 3; favorite.Name = "Favorite"; favorite.PointValue = PostVotePointValue.Favorite; postVotes.Add(favorite); PostVoteType offensive = new PostVoteType(); offensive.ID = 4; offensive.Name = "Offensive"; offensive.PointValue = PostVotePointValue.Offensive; postVotes.Add(offensive); PostVoteType spam = new PostVoteType(); spam.ID = 0; spam.Name = "Spam"; spam.PointValue = PostVotePointValue.Spam; postVotes.Add(spam); } } When the constructor is called the code above is ran. I have some functions that can query the data above too. But is this the best way to store information in asp.net? if not what would you recommend?

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  • Vector does reallocation on every push_back

    - by Amrish
    IDE - Visual Studio 2008, Visual C++ I have a custom class Class1 with a copy constructor to it. I also have a vector Data is inserted using the following code Class1* objClass1; vector<Class1> vClass1; for(int i=0;i<1000;i++) { objClass1 = new Class1(); vClass1.push_back(*objClass1); delete objClass1; } Now on every insert, the vector gets re-allocated and all the existing contents are copied to new locations. For example, if the vector has 5 elements and if I insert the 6th one, the previous 5 elements along with the new one gets copied to a new location (I figured it out by adding log statements in the copy constructors.) On using reserve(), this however does not happen as expected! I have the following questions Is it mandatory to always use the reserve statement? Does vector does a reallocation every time I do a push_back; or does it happen because I am debugging?

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  • WPF Binding Path=/ not working?

    - by Mark
    I've set up my DataContext like this: <Window.DataContext> <c:DownloadManager /> </Window.DataContext> Where DownloadManager is Enumerable<DownloadItem>. Then I set my DataGrid like this: <DataGrid Name="dataGrid1" ItemsSource="{Binding Path=/}" ... So that it should list all the DownloadItems, right? So I should be able to set my columns like: <DataGridTextColumn Binding="{Binding Path=Uri, Mode=OneWay}" Where Uri is a property of the DownloadItem. But it doesn't seem to like this. In the visual property editor, it doesn't recognize Uri is a valid property, so I'm guessing I'm doing something wrong. It was working before, when I had the data grid binding to Values, but then I took that enumerable out of the DownloadManager and made itself enumerable. How do I fix this? PS: By "doesn't work" I mean it doesn't list any items. I've added some to the constructor of the DM, so it shouldn't be empty.

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  • Usage Rails 3.0 beta 3 without ActiveRecoord ORM

    - by Anton
    Hi everybody! Just installed Rails 3.0 beta 3 in Windows 7. And started playing with some easy examples class SignupController < ApplicationController def index @user = User.new(params[:user]) if method.post? and @user.save redirect_to :root end end end class User def initialize(params = {}) @email = params[:email] @passw = params[:passw] end def save end end <div align="center"> <% form_for :user do |form| %> <%= form.label :email %> <%= form.text_field :email %><br /> <%= form.label :password %> <%= form.text_field :password %><br /> <%= form.submit :Register! %> <% end %> </div> When I go to /signup I'm getting this error NoMethodError in SignupController#index You have a nil object when you didn't expect it! You might have expected an instance of Array. The error occurred while evaluating nil.[] Is there a problem with constructor or what's wrong?Please, need your help!

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  • Why do I get Error#2036 in flash AS3 and how to solve this?

    - by sydas
    I'm currently building an application in flash in relation to RSS/XML feeds for a project. I'm stuck at the moment because I keep getting this error: Error opening URL 'http://distilleryimage6.instagram.com/.jpg' Error #2044: Unhandled IOErrorEvent:. text=Error #2036: Load Never Completed. I know my string picURL is not functioning properly, but am I missing something that makes it not functional? This is my code: package { import flash.display.*; import flash.events.*; import flash.net.*; public class instagramFeed extends MovieClip { //link to #rit xml loader public var ritFileRequest = new URLRequest("http://instagram.com/tags/rit/feed/recent.rss"); public var ritXmlLoader = new URLLoader(); //link to #rochester xml loader // same as above public variables public function instagramFeed() { // constructor code trace("About to load..."); //Loads #rit hashtag xml data. ritXmlLoader.load(ritFileRequest); ritXmlLoader.addEventListener(Event.COMPLETE, displayRITInfo); } //focuses on data with #rit hashtag public function displayRITInfo(e:Event):void{ var ritInstagramData:XML = new XML(ritXmlLoader.data); var ritInfoList:XMLList = ritInstagramData.elements().item; trace(ritInfoList); //load the image var ritPic:String = ritInfoList.*::condition.@code; var picURL:String = "http://distilleryimage6.instagram.com/" + ritPic + ".jpg"; trace(picURL); //show the image on the stage! var ritImageRequest:URLRequest = new URLRequest(picURL); var ritImageLoader:Loader = new Loader(); ritImageLoader.load(ritImageRequest); addChild(ritImageLoader); ritImageLoader.x=200; ritImageLoader.y=100; ritImageLoader.scaleX = 3; ritImageLoader.scaleY = 3; } } }

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  • Which pattern to use for logging? Dependency Injection or Service Locator?

    - by andlju
    Consider this scenario. I have some business logic that now and then will be required to write to a log. interface ILogger { void Log(string stuff); } interface IDependency { string GetInfo(); } class MyBusinessObject { private IDependency _dependency; public MyBusinessObject(IDependency dependency) { _dependency = dependency; } public string DoSomething(string input) { // Process input var info = _dependency.GetInfo(); var intermediateResult = PerformInterestingStuff(input, info); if (intermediateResult== "SomethingWeNeedToLog") { // How do I get to the ILogger-interface? } var result = PerformSomethingElse(intermediateResult); return result; } } How would you get the ILogger interface? I see two main possibilities; Pass it using Dependency Injection on the constructor. Get it via a singleton Service Locator. Which method would you prefer, and why? Or is there an even better pattern? Update: Note that I don't need to log ALL method calls. I only want to log a few (rare) events that may or may not occur within my method.

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  • Python NameError when attempting to use a user-defined class

    - by Michael Herold
    I'm getting a weird instance of a NameError when attempting to use a class I wrote. In a directory, I have the following file structure: dir/ ReutersParser.py test.py reut-xxx.sgm Where my custom class is defined in ReutersParser.py and I have a test script defined in test.py. The ReutersParser looks something like this: from sgmllib import SGMLParser class ReutersParser(SGMLParser): def __init__(self, verbose=0): SGMLParser.__init__(self, verbose) ... rest of parser if __name__ == '__main__': f = open('reut2-short.sgm') s = f.read() p = ReutersParser() p.parse(s) It's a parser to deal with SGML files of Reuters articles. The test works perfectly. Anyway, I'm going to use it in test.py, which looks like this: from ReutersParser import ReutersParser def main(): parser = ReutersParser() if __name__ == '__main__': main() When it gets to that parser line, I'm getting this error: Traceback (most recent call last): File "D:\Projects\Reuters\test.py", line 34, in <module> main() File "D:\Projects\Reuters\test.py", line 19, in main parser = ReutersParser() File "D:\Projects\Reuters\ReutersParser.py", line 38, in __init__ SGMLParser.__init__(self, verbose) NameError: global name 'sgmllib' is not defined For some reason, when I try to use my ReutersParser in test.py, it throws an error that says it cannot find sgmllib, which is a built-in module. I'm at my wits' end trying to figure out why the import won't work. What's causing this NameError? I've tried importing sgmllib in my test.py and that works, so I don't understand why it can't find it when trying to run the constructor for my ReutersParser.

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  • Error with threads during automatic testing on TeamCity 5

    - by yeyeyerman
    Hello, I'm having some problems executing the tests of the application I'm developing. All the tests execute normally with ReSharper and in NCover. However, the execution of one of these tests in TeamCity is generating an error. This test initializes two objects, the object under test and a simulator of a real object. Both objects will communicate throug a serial link in a representation of the real scenario. ObjectSimulator r_simulator = new ObjectSimulator(...); ObjectDriver r_driver = new ObjectDriver(...); Assert.IsTrue(r_driver.Connect() == ErrorCode.Success); The simulator just do the following in the constructor public class ObjectSimulator { ... public ObjectSimulator() { // serial port configuration m_port = new SerialPort(); m_port.DataReceived += DataReceivedEvent; } ... } The main object has two threads. The main thread of the application and a timer to refresh a watchdog timer in the real object. public ErrorCode Connect() { ... StartSynchroTimer(); Thread.Sleep(4); // to check if the timer is working properly ... } The problem is comming from the Thread.Sleep() call, as when I remove it everything works. It seems like the ObjectSimulator also sleeps and doesn't receive the DataReceived event. How can I resolve this issue?

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  • Working with Java using methods and arrays [closed]

    - by jordan
    Hi i'm a newb at java and for one of my labs I have to create a instant messenger client with these requirements: add buddyList instance variable add IMClient constructor to create ArrayList addBuddy method removeBuddy method findBuddy method printBuddyList method what's the best way to go about this? so far I have this: public class IMClient { private String userId; // User id private String password; // Password private int status; // Status code for user: 1 - Online, 2 - Off-line, 3 - Away public IMClient(String userId, String password, int status) { super(); this.userId = userId; this.password = password; this.status = status; } // Returns true if password as a parameter matches password instance variable. public boolean checkPassword(String password) { return this.password.equals(password); } public String toString() { StringBuffer buf = new StringBuffer(100); buf.append(" User id: "); buf.append(userId); buf.append(" Password: "); buf.append(password); buf.append(" Status: "); buf.append(status); return buf.toString(); } public String getUserId() { return userId; } public void setUserId(String userId) { this.userId = userId; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public int getStatus() { return status; } public void setStatus(int status) { this.status = status; } public static void main(String[] args) { } }

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  • Generics in a bidirectional association

    - by Verhoevenv
    Let's say I have two classes A and B, with B a subtype of A. This is only part of a richer type hierarchy, obviously, but I don't think that's relevant. Assume A is the root of the hierarchy. There is a collection class C that keeps track of a list of A's. However, I want to make C generic, so that it is possible to make an instance that only keeps B's and won't accept A's. class A(val c: C[A]) { c.addEntry(this) } class B(c: C[A]) extends A(c) class C[T <: A]{ val entries = new ArrayBuffer[T]() def addEntry(e: T) { entries += e } } object Generic { def main(args : Array[String]) { val c = new C[B]() new B(c) } } The code above obviously give the error 'type mismatch: found C[B], required C[A]' on the new B(c) line. I'm not sure how this can be fixed. It's not possible to make C covariant in T (like C[+T <: A]) because the ArrayBuffer is non-variantly typed in T. It's not possible to make the constructor of B require a C[B] because C can't be covariant. Am I barking up the wrong tree here? I'm a complete Scala newbie, so any ideas and tips might be helpful. Thank you! EDIT: Basically, what I'd like to have is that the compiler accepts both val c = new C[B]() new B(c) and val c = new C[A]() new B(c) but would reject val c = new C[B]() new A(c) It's probably possible to relax the typing of the ArrayBuffer in C to be A instead of T, and thus in the addEntry method as well, if that helps.

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  • declare decision structure inside of a System.out.println

    - by user2899249
    So I am working on an assignment where I have to have a print method in a constructor that displays a distance. I also have to have three separate get methods depending on what the input is in the demo class. My question is that I am trying to write the print method to contain a decision structure based on which get is used. public void prt() { DecimalFormat formatter = new DecimalFormat("#,##0.00"); System.out.println("The time it takes the sound to travel " + distance + " feet through air is " + if (getSpeedInAir() > 0) { formatter.format(getSpeedInAir()); } else if (getSpeedInWater() > 0) { formatter.format(getSpeedInWater()); } else if (getSpeedInSteel() > 0) { formatter.format(getSpeedInSteel()); } else "error";) } After trying to compile I am getting the following errors. Microsoft Windows [Version 6.1.7601] Copyright (c) 2009 Microsoft Corporation. All rights reserved. C:\Users\GlaDOS\Desktop\JavaStuffj Speed C:\Users\GlaDOS\Desktop\JavaStuffdel *.class C:\Users\GlaDOS\Desktop\JavaStuffjavac Speed.java Speed.java:43: error: illegal start of expression " feet through air is " + if (getSpeedInAir() 0) ^ Speed.java:43: error: ';' expected " feet through air is " + if (getSpeedInAir() 0) ^ Speed.java:43: error: not a statement " feet through air is " + if (getSpeedInAir() 0) ^ Speed.java:43: error: ';' expected " feet through air is " + if (getSpeedInAir() 0) ^ Speed.java:47: error: 'else' without 'if' else if (getSpeedInWater() > 0) ^ Speed.java:56: error: not a statement "error";) ^ Speed.java:56: error: illegal start of expression "error";) ^ 7 errors C:\Users\GlaDOS\Desktop\JavaStuffjava Speed Error: Could not find or load main class Speed Any help on why this is happening would be greatly appreciated.

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  • How to get TextWidth of string (without Canvas)?

    - by lyborko
    Hi, I would like to get text width of a string before an application starts. Everything works fine untill Application.MainForm canvas present. The problem is, when I try dynamicaly create TOrdinarium in the OnCreate event of the app. main form, "Canvas does not allow drawing" error occures. (Application.MainForm is nil....). I tried several ways to create Canvas dynamicaly (one of them is written below), but it can not measure text sizes without being attached to parented control. Is there way how to make it work somehow? Thanx I tried this: TOrdinarium = class (TCustomControl) private function GetVirtualWidth:integer; end; constructor TOrdinarium.Create(AOwner:TComponent); begin inherited; Width:=GetVirtualWidth; end; function TOrdinarium.GetVirtualWidth:integer; var ACanvas : TControlCanvas; begin ACanvas := TControlCanvas.Create; TControlCanvas(ACanvas).Control := Application.MainForm; ACanvas.Font.Assign(Font); result:=ACanvas.TextWidth('0'); ACanvas.Free; end;

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  • java phone number validation....

    - by user69514
    Here is my problem: Create a constructor for a telephone number given a string in the form xxx-xxx-xxxx or xxx-xxxx for a local number. Throw an exception if the format is not valid. So I was thinking to validate it using a regular expression, but I don't know if I'm doing it correctly. Also what kind of exception would I have to throw? Do I need to create my own exception? public TelephoneNumber(String aString){ if(isPhoneNumberValid(aString)==true){ StringTokenizer tokens = new StringTokenizer("-"); if(tokens.countTokens()==3){ areaCode = Integer.parseInt(tokens.nextToken()); exchangeCode = Integer.parseInt(tokens.nextToken()); number = Integer.parseInt(tokens.nextToken()); } else if(tokens.countTokens()==2){ exchangeCode = Integer.parseInt(tokens.nextToken()); number = Integer.parseInt(tokens.nextToken()); } else{ //throw an excemption here } } } public static boolean isPhoneNumberValid(String phoneNumber){ boolean isValid = false; //Initialize reg ex for phone number. String expression = "(\\d{3})(\\[-])(\\d{4})$"; CharSequence inputStr = phoneNumber; Pattern pattern = Pattern.compile(expression); Matcher matcher = pattern.matcher(inputStr); if(matcher.matches()){ isValid = true; } return isValid; } Hi sorry, yes this is homework. For this assignments the only valid format are xxx-xxx-xxxx and xxx-xxxx, all other formats (xxx)xxx-xxxx or xxxxxxxxxx are invalid in this case. I would like to know if my regular expression is correct

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  • dynamic inheritance without touching classes

    - by Jasper
    I feel like the answer to this question is really simple, but I really am having trouble finding it. So here goes: Suppose you have the following classes: class Base; class Child : public Base; class Displayer { public: Displayer(Base* element); Displayer(Child* element); } Additionally, I have a Base* object which might point to either an instance of the class Base or an instance of the class Child. Now I want to create a Displayer based on the element pointed to by object, however, I want to pick the right version of the constructor. As I currently have it, this would accomplish just that (I am being a bit fuzzy with my C++ here, but I think this the clearest way) object->createDisplayer(); virtual void Base::createDisplayer() { new Displayer(this); } virtual void Child::createDisplayer() { new Displayer(this); } This works, however, there is a problem with this: Base and Child are part of the application system, while Displayer is part of the GUI system. I want to build the GUI system independently of the Application system, so that it is easy to replace the GUI. This means that Base and Child should not know about Displayer. However, I do not know how I can achieve this without letting the Application classes know about the GUI. Am I missing something very obvious or am I trying something that is not possible?

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  • How do I access abstract private data from derived class without friend or 'getter' functions in C++?

    - by John
    So, I am caught up in a dilemma right now. How am I suppose to access a pure abstract base class private member variable from a derived class? I have heard from a friend that it is possible to access it through the base constructor, but he didn't explain. How is it possible? There are some inherited classes from base class. Is there any way to gain access to the private variables ? class Base_button { private: bool is_vis; Rect rButton; public: // Constructors Base_button(); Base_button( const Point &corner, double height, double width ); // Destructor virtual ~ Base_button(); // Accessors virtual void draw() const = 0; bool clicked( const Point &click ) const; bool is_visible() const; // Mutators virtual void show(); virtual void hide(); void move( const Point &loc ); }; class Button : public Base_button { private: Message mButton; public: // Constructors Button(); Button( const Point &corner, const string &label ); // Acessors virtual void draw() const; // Mutators virtual void show(); virtual void hide(); }; I want to be able access Rect and bool in the base class from the subclass

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  • static member specialization of templated child class and templated base class

    - by b3nj1
    I'm trying to have a templated class (here C) that inherits from another templated class (here A) and perform static member specialization (of int var here), but I cant get the right syntax to do so (if it's possible #include <iostream> template<typename derived> class A { public: static int var; }; //This one works fine class B :public A<B> { public: B() { std::cout << var << std::endl; } }; template<> int A<B>::var = 9; //This one doesn't works template<typename type> class C :public A<C<type> > { public: C() { std::cout << var << std::endl; } }; //template<> template<typename type> int A<C<type> >::a = 10; int main() { B b; C<int> c; return 0; } I put an example that works with a non templated class (here B) and i can get the static member specialization of var, but for C that just doesn't work. Here is what gcc tells me : test.cpp: In constructor ‘C<type>::C()’: test.cpp:29:26: error: ‘var’ was not declared in this scope test.cpp: At global scope: test.cpp:34:18: error: template definition of non-template ‘int A<C<type> >::a’ I'm using gcc version 4.6.3, thanks for any help

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  • Complicated .NET factory design

    - by Tom W
    Hello SO; I'm planning to ask a fairly elaborate question that is also something of a musing here, so bear with me... I'm trying to design a factory implementation for a simulation application. The simulation will consist of different sorts of entities i.e. it is not a homogenous simulation in any respect. As a result, there will be numerous very different concrete implementations and only the very general properties will be abstracted at the top level. What I'd like to be able to do is create new simulation entities by calling a method on the model with a series of named arguments representing the parameters of the entity, and have the model infer what type of object is being described by the inbound parameters (from the names of the parameters and potentially the sequence they occur in) and call a factory method on the appropriate derived class. For example, if I pass the model a pair of parameters (Param1=5000, Param2="Bacon") I would like it to infer that the names Param1 and Param2 'belong' to the class "Blob1" and call a shared function "getBlob1" with named parameters Param1:=5000, Param2:="Bacon" whereas if I pass the model (Param1=5000, Param3=50) it would call a similar factory method for Blob2; because Param1 and Param3 in that order 'belong' to Blob2. I foresee several issues to resolve: Whether or not I can reflect on the available types with string parameter names and how to do this if it's possible Whether or not there's a neat way of doing the appropriate constructor inference from the combinatoric properties of the argument list or whether I'm going to have to bodge something to do it 'by hand'. If possible I'd like the model class to be able to accept parameters as parameters rather than as some collection of keys and values, which would require the model to expose a large number of parametrised methods at runtime without me having to code them explicitly - presumably one for every factory method available in the relevant namespace. What I'm really asking is how you'd go about implementing such a system, rather than whether or not it's fundamentally possible. I don't have the foresight or experience with .NET reflection to be able to figure out a way by myself. Hopefully this will prove an informative discussion.

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  • How can I theme custom form(drupal 6.x)

    - by Andrew
    DRUPAL 6.X I have this custom form constructor inside my custom module which is invoke through ajax request. I’m attempting to theme this form with the template file reside in my theme directory. For that matter, I’ve registered my theme inside template.php file which reside in my theme folder. Here’s how this file looks – function my_theme() { return array( 'searchdb' => array( 'arguments' => array('form' => NULL), 'template' => 'searchform', ) ); } And the following is the excerpt of module code – function test_menu() { $my_form['searchdb'] = array( 'title' => 'Search db', 'page callback' => 'get_form', 'page arguments' => array(0), 'access arguments' => array('access content'), 'type' => MENU_CALLBACK, ); return $my_form; } function get_form($formtype){ switch($formtype){ case 'searchdb' : echo drupal_get_form('searchdb'); break; } } function searchdb(){ $form['customer_name'] = array( '#type' => 'textfield', '#title' => t('Customer Name'), '#size' => 50, '#attributes' => array('class' => 'name-textbox'), ); return $form; } As you can imagine, this is not working at all. Just to test if my theme is even registered, I’ve also tested with theme function but, it’s not called. I've checked template file name and form-id(through the outputted html source) and everything seems ok. I would be glad if anyone could point me to the right direction.

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  • Where should I put validation code?

    - by D Lawson
    I'm creating interfaces and abstract classes that represent a messaging framework for short text-based messages like SMS, email, twitter, xml, etc.. and I was wondering where I should put the message validation code. The thing is that I am only writing the superclasses and interfaces, so I'm not putting the actual implementation in, I'll just put the hooks in that allow others to validate the content of the messages. The way I see it, I could do it several ways: in the abstract superclass "Message", have an abstract method 'isValid'. A variation on this would be to have isValid be called when the Message constructor is called, throwing a MalformedMessageException if the message is formatted incorrectly. in the transport layer, immediately before sending, validate the message. I would have a send(Message) method that calls an isValid(Message) method immediately before it sends. have a singleton message validator with a static method isValid(Message) that is called at some point. I'm sure there are other options that I'm missing. Currently, I'm leaning towards the first one, but it doesn't feel right to me to have validation code in what should be a domain object.

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  • C# generics with MVVM, pulling the T out of <T>

    - by bufferz
    My Model is a generic class that contains a (for example) Value property which can be int, float, string, bool, etc. So naturally this class is represented something like Model<T>. For the sake of collections Model<T> implements the interface IModel, although IModel is itself empty of any content. My ViewModel contains and instance of Model<T> and it is passed in through ViewModel's constructor. I still want to know what T is in ViewModel, so when I expose Model to the View I know the datatype of Model's buried Value property. The class for ViewModel ends up looking like the following: class ViewModel<T> { private Model<T> _model; public ViewModel(Model<T> model) { ....blah.... } public T ModelsValue {get; set; } } This works fine, but is limited. So now I need to expose a collection of IModels with varying Ts to my View, so I'm trying to set up an ObservableCollection of new ViewModel<T>s to a changing list of IModels. The problem is, I can't figure out how to get T from Model<T> from IModel to construct ViewModel<T>(Model<T>) at runtime. In the VS2010 debugger I can mouseover any IModel object and see its full Model<int> for example at runtime so I know the data is in there. Any ideas?

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  • Porting Symbian C++ to Android NDK

    - by Donal Rafferty
    I've been given some Symbian C++ code to port over for use with the Android NDK. The code has lots of Symbian specific code in it and I have very little experience of C++ so its not going very well. The main thing that is slowing me down is trying to figure out the alternatives to use in normal C++ for the Symbian specific code. At the minute the compiler is throwing out all sorts of errors for unrecognised types. From my recent research these are the types that I believe are Symbian specific: TInt, TBool, TDesc8, RSocket, TInetAddress, TBuf, HBufc, RPointerArray Changing TInt and TBool to int and bool respectively works in the compiler but I am unsure what to use for the other types? Can anyone help me out with them? Especially TDesc, TBuf, HBuf. Also Symbian has a two phase contructor using NewL and NewLc But would changing this to a normal C++ constructor be ok? Finally Symbian uses the clean up stack to help eliminate memory leaks I believe, would removing the clean up stack code be acceptable, I presume it should be replaced with try/catch statements?

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  • how are association, aggregation and composition written?

    - by ajsie
    i have read some posts about the differences between these 3 relationships and i think i get the point. i just wonder, are all these written the same when coding? question 1: all 3 are just a value of the object type in a instance variable? class A { public $b = '' public function __construct($object) { $this->b = $object // <-- could be a association, aggregation or a composition relation? } } question 2: does it have to be an instance variable or can it be a static one? class A { public static $b = '' // <-- nothing changed? public function __construct($object) { $this->b = $object } } question 3: is there a difference in where the object is created? i tend to think that composition object is created inside the object: class A { public $b = '' public function __construct() { $this->b = new Object // is created inside the object } } and aggregation/association is passed through a constructor or another method: class A { public $b = '' public function __construct($object) { // passed through a method $this->b = $object } } question 4: why/when is this important to know. do i have to comment an object inside another what relation its about or do you do it in an UML diagram? could someone shed a light on these questions. thanks!

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  • calling a function from a set of overloads depending on the dynamic type of an object

    - by Jasper
    I feel like the answer to this question is really simple, but I really am having trouble finding it. So here goes: Suppose you have the following classes: class Base; class Child : public Base; class Displayer { public: Displayer(Base* element); Displayer(Child* element); } Additionally, I have a Base* object which might point to either an instance of the class Base or an instance of the class Child. Now I want to create a Displayer based on the element pointed to by object, however, I want to pick the right version of the constructor. As I currently have it, this would accomplish just that (I am being a bit fuzzy with my C++ here, but I think this the clearest way) object->createDisplayer(); virtual void Base::createDisplayer() { new Displayer(this); } virtual void Child::createDisplayer() { new Displayer(this); } This works, however, there is a problem with this: Base and Child are part of the application system, while Displayer is part of the GUI system. I want to build the GUI system independently of the Application system, so that it is easy to replace the GUI. This means that Base and Child should not know about Displayer. However, I do not know how I can achieve this without letting the Application classes know about the GUI. Am I missing something very obvious or am I trying something that is not possible?

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  • Calling base Text method on custom TextBox

    - by The Demigeek
    I'm trying to create a CurrencyTextBox that inherits from TextBox. I'm seeing some really weird behavior that I just don't understand. After lots of testing, I think I can summarize as follows: In the class code, when I access base.Text (to get the textbox's text), I'm actually getting the return value of my overridden Text property. I thought the base keyword would ensure that the underlying object's methods get called. To demonstrate: public class cTestTextBox : System.Windows.Forms.TextBox { string strText = ""; public cTestTextBox() { SetVal("AAA"); base.Text = "TEST"; } public override string Text { get { string s = strText; s = "++" + s + "++"; return s; } } public void SetVal(string val) { strText = val; } } Place this control on a form and set a breakpoint on the constructor. Run the app. Hover your mouse over the base.Text expression. Note that the tooltip shows you the value of the overridden property, not the base property. Execute the SetVal() statement and again hover your mouse over the base.Text expression. Note that the tooltop shows you the value of the overridden property, not the base property. How do I reliably access the Text property of the textbox from which I'm inheriting?

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  • Another thread safe queue implementation

    - by jensph
    I have a class, Queue, that I tried to make thread safe. It has these three member variables: std::queue<T> m_queue; pthread_mutex_t m_mutex; pthread_cond_t m_condition; and a push and pop implemented as: template<class T> void Queue<T>::push(T value) { pthread_mutex_lock( &m_mutex ); m_queue.push(value); if( !m_queue.empty() ) { pthread_cond_signal( &m_condition ); } pthread_mutex_unlock( &m_mutex ); } template<class T> bool Queue<T>::pop(T& value, bool block) { bool rtn = false; pthread_mutex_lock( &m_mutex ); if( block ) { while( m_queue.empty() ) { pthread_cond_wait( &m_condition, &m_mutex ); } } if( !m_queue.empty() ) { value = m_queue.front(); m_queue.pop(); rtn = true; } pthread_mutex_unlock( &m_mutex ); return rtn; } Unfortunately there are occasional issues that may be the fault of this code. That is, there are two threads and sometimes thread 1 never comes out of push() and at other times thread 2 never comes out of pop() (the block parameter is true) though the queue isn't empty. I understand there are other implementations available, but I'd like to try to fix this code, if needed. Anyone see any issues? The constructor has the appropriate initializations: Queue() { pthread_mutex_init( &mMutex, NULL ); pthread_cond_init( &mCondition, NULL ); } and the destructor, the corresponding 'destroy' calls.

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