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  • Can I have fixed typed ArrayList in C#, just like C++?

    - by Kazoom
    I have an ArrayList which contains fixed type of objects. However everytime I need to extract an object a particular index, I need to typecast it to my user defined type from object type. Is there a way in C# to declare ArrayList of fixed types just like Java and C++, or is there a work around to avoid the typecasting everytime? Edit: I apologize I forgot mentioning that I require the datastructure to be thread-safe, which List is not. Otherwise I would have just used a normal Array. But I want to save myself from the effort of explicitly locking and unlocking while writing the array. So I thought of using ArrayList, synchronize it, but it requires typecasting every time.

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  • Converting BindingList(Of T) to Array

    - by George
    Public Class Orders Inherits System.ComponentModel.BindingList(Of Order) End Class Public Sub DataBind(ByVal Orders() As Orders) End Sub Dim MyOrders() As Order = Orders.ToArray SuperListBinder.DataBind(MyOrders) '<<Error occurs on this line I don't understand this error. I think that I am passing the appropriate data type to a sub. I don't understand the meaning of "Cannot convert object of type x to an object of type x! Note that, if relevant, my Solution File contains ,multiple projects and that they are all project references. Error: Error 1 Value of type '1-dimensional array of BESI.BusinessObjects.Order' cannot be converted to '1-dimensional array of BESI.BusinessObjects.Orders' because 'BESI.BusinessObjects.Order' is not derived from 'BESI.BusinessObjects.Orders'. C:\My\Code\BESI\BesiAdmin\Forms\Activity.vb 17 34 BesiAdmin

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  • Multithreading with STL container

    - by Steven
    I have an unordered map which stores a pointer of objects. I am not sure whether I am doing the correct thing to maintain the thread safety. typedef std::unordered_map<string, classA*>MAP1; MAP1 map1; pthread_mutex_lock(&mutexA) if(map1.find(id) != map1.end()) { pthread_mutex_unlock(&mutexA); //already exist, not adding items } else { classA* obj1 = new classA; map1[id] = obj1; obj1->obtainMutex(); //Should I create a mutex for each object so that I could obtain mutex when I am going to update fields for obj1? pthread_mutex_unlock(&mutexA); //release mutex for unordered_map so that other threads could access other object obj1->field1 = 1; performOperation(obj1); //takes some time obj1->releaseMutex(); //release mutex after updating obj1 }

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  • C# NetworkAvailibilityChanged doesn't trigger on disconnect

    - by Nickolay Kondratyev
    My goal is to detect when the Ethernet cable gets disconnected I am attempting to use NetworkChange class but the event NetworkAvailibilityChanged does not trigger when I unplug Ethernet cable. NetworkAddressChanged does get triggered in about 8 seconds but NetworkAvailibilityChanged never does, is there is anything am I am missing? public partial class Form1 : Form { public Form1() { InitializeComponent(); NetworkChange.NetworkAvailabilityChanged += new NetworkAvailabilityChangedEventHandler(NetworkChange_NetworkAvailabilityChanged); NetworkChange.NetworkAddressChanged += new NetworkAddressChangedEventHandler(NetworkChange_NetworkAddressChanged); } void NetworkChange_NetworkAvailabilityChanged(object sender, NetworkAvailabilityEventArgs e) { Console.WriteLine("NetworkChange_NetworkAvailabilityChanged"); } void NetworkChange_NetworkAddressChanged(object sender, EventArgs e) { Console.WriteLine("NetworkChange_NetworkAddressChanged"); } }

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  • ArrayBlockingQueue exceeds given capacity

    - by Wojciech Reszelewski
    I've written program solving bounded producer & consumer problem. While constructing ArrayBlockingQueue I defined capacity 100. I'm using methods take and put inside threads. And I've noticed that sometimes I see put 102 times with any take's between them. Why does it happen? Producer run method: public void run() { Object e = new Object(); while(true) { try { queue.put(e); } catch (InterruptedException w) { System.out.println("Oj, nie wyszlo, nie bij"); } System.out.println("Element added"); } } Consumer run method: public void run() { while(true) { try { queue.take(); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println("Element removed"); } } Part of uniq -c on file with output: 102 Element removed 102 Element added 102 Element removed 102 Element added 102 Element removed 102 Element added 102 Element removed 102 Element added 102 Element removed 102 Element added 102 Element removed 102 Element added 2 Element removed 2 Element added 102 Element removed 102 Element added

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  • How to pass a value between Silverlight pages for WP7?

    - by Sebastian Gray
    I've got a MainPage.xaml page a Detail.xaml page. I've passed variables to the Detail.xaml from MainPage.xaml by using a static variable and referencing it in Detail.xaml (the detail page is acting like a dialog). However once I've updated the content of another object, I want to call a method in MainPage.xaml to refresh the content of that page using the updated object from the Detail.xaml page. I assume I am not using the correct paradigm for this and should probably be using MVVM or something but I'm not familiar with the implementation and was hoping there was a simple way to do this?

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  • Inheritance of jQuery's prototype partially fails

    - by user1065745
    I want to use Coffeescript to create an UIObject class. This class should inherit from jQuery, so that instances of UIObject can be used as if they where created with jQuery. class UIObject isObject: (val) -> typeof val is "object" constructor: (tag, attributes) -> @merge jQuery(tag, attributes), this @UIObjectProperties = {} merge: (source, destination) -> for key of source if destination[key] is undefined destination[key] = source[key] else if @isObject(source[key]) @merge(source[key], destination[key]) return It partially works. Consider the Foobar class below: class Foobar extends UIObject constructor: -> super("<h1/>", html: "Foobar") $("body").append(new Foobar) works fine. BUT: (new Foobar).appendTo("body") places the tag, but also raises RangeError: Maximum call stack size exceeded. Was it just a bad idea to inherit from jQuery? Or is there a solurion? For those who don't know CoffeeScript, the JavaScript source is: var Foobar, UIObject; var __hasProp = Object.prototype.hasOwnProperty, __extends = function(child, parent) { for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor; child.__super__ = parent.prototype; return child; }; UIObject = (function () { UIObject.prototype.isObject = function (val) { return typeof val === "object"; }; function UIObject(tag, attributes) { this.merge(jQuery(tag, attributes), this); this.UIObjectProperties = {}; } UIObject.prototype.merge = function (source, destination) { var key; for (key in source) { if (destination[key] === void 0) { destination[key] = source[key]; } else if (this.isObject(source[key])) { this.merge(source[key], destination[key]); } } }; return UIObject; })(); Foobar = (function () { __extends(Foobar, UIObject); function Foobar() { Foobar.__super__.constructor.call(this, "<h1/>", { html: "Foobar" }); } return Foobar; })();

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  • Cannot pass a input from text box to a query string and then keep the string in this box.

    - by Nikita Barsukov
    I have a simple ASP.net page: <form id="form1" runat="server"> <p><asp:TextBox id="input_box" runat="server"></asp:TextBox> <asp:Button Text="OK" runat="server" OnClick="run" /></p> </form> I want to send input from input_box to a query string, and then keep this input in the input_box when the page reloads. That's the code behind page: protected void Page_Load(object sender, EventArgs e) { input_box.Text = Request.QueryString["input"]; } protected void run(object sender, EventArgs e) { string url = string.Format("?input={0}", input_box.Text); Response.Redirect(Request.Url.AbsolutePath + url); } Problem is that when query string is not empty, string from input_box cannot be passed to query string. How to correct it?

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  • Right design to validate attributes of a class instance

    - by systempuntoout
    Having a simple Python class like this: class Spam(object): __init__(self, description, value): self.description = description self.value = value Which is the correct approach to check these constraints: "description cannot be empty" "value must be greater than zero" Should i: 1.validate data before creating spam object ? 2.check data on __init__ method ? 3.create an is_valid method on Spam class and call it with spam.isValid() ? 4.create an is_valid static method on Spam class and call it with Spam.isValid(description, value) ? 5.check data on setters? 6.... Could you recommend a well designed\Pythonic\not verbose (on class with many attributes)\elegant approach?

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  • Django: Data corrupted after loading? (possible programmer error)

    - by Rosarch
    I may be loading data the wrong way. excerpt of data.json: { "pk": "1", "model": "myapp.Course", "fields": { "name": "Introduction to Web Design", "requiredFor": [9], "offeringSchool": 1, "pre_reqs": [], "offeredIn": [1, 5, 9] } }, I run python manage.py loaddata -v2 data: Installed 36 object(s) from 1 fixture(s) Then, I go to check the above object using the Django shell: >>> info = Course.objects.filter(id=1) >>> info.get().pre_reqs.all() [<Course: Intermediate Web Programming>] # WRONG! There should be no pre-reqs >>> from django.core import serializers >>> serializers.serialize("json", info) '[{"pk": 1, "model": "Apollo.course", "fields": {"pre_reqs": [11], "offeredIn": [1, 5, 9], "offeringSchool": 1, "name": "Introduction to Web Design", "requiredFor": [9]}}]' The serialized output of the model is not the same as the input that was given to loaddata. The output has a non-empty pre_req list, whereas the input's pre_reqs field is empty. What am I doing wrong?

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  • Java: Reflection against casting when you know superclass

    - by Ema
    I don't know exactly how to define my doubt so please be patient if the question has already been asked. Let's say I have to dinamically instantiate an object. This object will surely be instance of a subclass of a known, immutable class A. I can obtain dinamically the specific implementation class. Would it be better to use reflection exactly as if I didn't know anything about the target class, or would it be preferrable/possible to do something like: A obj = (Class.forName("com.package.Sub-A")) new A(); where Sub-A extends A ? The purpose would be to avoid reflection overhead times... Thank you in advance.

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  • Rails -- Cant set value for date_select in form

    - by ChrisWesAllen
    I'm pulling data from an API where the date data comes in as "2008-02-11 00:00:00 " I would like that data to go into my form within the date_select as a value so I can view it correctly before I add it into my database. The view looks like <%= f.label :start_date %><br /> <%= f.date_select :start_date, :value => " #{@stdate[idx]} " %> The object is actually an array of dates since I'm doing this action several times do thats why the [idx] is there; serving as an index. <%= @stdate[idx] % ends up outputting "2008-02-11 00:00:00 " but the fields for the date_select helper only outputs the current date "2010" "June" "5" in those dropdown date selects fields... Do I need to set the values of the Year, Month, and Date Individually? I have Chronic and tried to parse the object before using it as a value for the date_select and that didnt work either. Any ideas?

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  • Using NSArray for C-type int comparisons

    - by Andrew Barinov
    I would like to iterate through an NSArray of ints and compare each one to a specific int. All ints are C type ints. The code I am using is as follows: -(int)ladderCalc: (NSArray*)amounts: (int)amount { int result; for (NSUInteger i=0; i< [amounts count]; i++) { if (amount < [amounts objectAtIndex:i]); { // do something } // do something } } However I get an error when comparing the int amount to the result of [amounts objectAtIndex:i] because you cannot compare id to int. Why is the id involved in this case? Shouldn't objectAtIndex just return the object at the index specified? Is it possible to cast the object returned to an C int and then do the comparison? Or should I just dispense with NSArray and do this type of thing in C?

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  • Casting as Interface? Awesome.

    - by cam
    I was just experimenting around with one of my programs, trying to make it looks prettier and I found something interesting. I have an interface that 4 classes inherit from. I found that if I pass the Class as an object to a method like so: ClassTest classtest = new ClassTest(); DoOperation(classtest); private void DoOperation(object o) { ((InterfaceClass)o).DoThis(); } So I can pass any type of class that inherits from InterfaceClass, and it will preform the proper interface operation? This is the coolest thing I've ever found from OOP (something I've never really studied) I really thought interfaces were created for the sole purpose of organization for developers. Are there more uses for interfaces than this?

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  • Get Python 2.7's 'json' to not throw an exception when it encounters random byte strings

    - by Chris Dutrow
    Trying to encode a a dict object into json using Python 2.7's json (ie: import json). The object has some byte strings in it that are "pickled" data using cPickle, so for json's purposes, they are basically random byte strings. I was using django.utils's simplejson and this worked fine. But I recently switched to Python 2.7 on google app engine and they don't seem to have simplejson available anymore. Now that I am using json, it throws an exception when it encounters bytes that aren't part of UTF-8. The error that I'm getting is: UnicodeDecodeError: 'utf8' codec can't decode byte 0x80 in position 0: invalid start byte It would be nice if it printed out a string of the character codes like the debugging might do, ie: \u0002]q\u0000U\u001201. But I really don't much care how it handles this data just as long as it doesn't throw an exception and continues serializing the information that it does recognize. How can I make this happen? Thanks!

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  • Does this simple cache class need thread synchronization?

    - by DayOne
    Does this simple cache class need thread synchronization ... if I remove the lock _syncLock statement will encounter any problems? I think i can remove the locks as the references should be updated correctly right? ... BUt i'm think whar happens if client code is iterating over the GetMyDataStructure method and it get replaced? Thanks! public sealed class Cache { private readonly object _syncLock = new object(); private IDictionary<int, MyDataStructure> _cache; public Cache() { Refresh(); } public void Refresh() { lock (_syncLock) { _cache = DAL.GetMyDataStructure(); } } public IDictionary<int, MyDataStructure> **GetMyDataStructure**() { lock (_syncLock) { return _cache; } } }

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  • C# Container Class

    - by Jamie
    I'm building a game in c# which allows you to script your own level, although I have come across a bit of a thought. I have a base class called "World" as an object. This was made with a simple: class World { However, when the user is scripting their level, all of the game objects will be contained in the world object. I want them to be able to do something on the lines of: World.ParentObjectName.ParentObjectProperty = "abc"; I know that the System.Windows.Forms.Panel and other classes are like containers and can have objects in them and be accessed in that kind of way... my question is how can I make a class which is like a container in which I can add objects to, and then access them with a World.ObjectName I have tried class World : System.Collections.CollectionBase, but with this method, I have to keep typing World.Item("ObjectName") Can anyone help? Thanks!

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  • How to model and handle presentation DTO's to abstract from complicated domain model?

    - by arrages
    Hi I am developing an application that needs to work with a complex domain model using Hibernate. This application uses Spring MVC and using the domain objects in the presentation layer is very messy so I think I should use DTO's that go to and from my service layer so that these match what I need in my views. Now lets assume I have a CarLease entity whose properties are not simple java primitives but it's composed with other entities like Make, Model, etc public class CarLease { private Make make; Private Model model; . . . } most properties are in this fashion and they are selectable using drop down selects on the jsp view, each will post back an ID to the controller. Now considering some standard use cases: create, edit, display How would you go about modeling the presentation DTO's to be used as form backing objects and communication between presentation and service layers?? Would you create a different DTO for each case (create, edit, display), would you make DTO's for the complex attributes? if so where would you translate the ID to entity? how and where would you handle validation, DTO/Domain assembly, what would you return from service layer methods? (create, edit, get) As you can see, I now I will benefit by separating my view from the domain objects (very complex with lots of stuff I don't need.) but I am having a hard time finding any real world examples and best practices for this. I need some architecture guidance from top to bottom, please keep in mind I will use Spring MVC in case that may leverage on your anwser. thanks in advance.

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  • What do you name the "other" kind of view-model in an MVVM project?

    - by DanM
    With MVVM, I think of a view-model as a class that provides all the data and commands that a view needs to bind to. But what happens when I have a database entity object, say a Customer, and I want to build a class that shapes or flattens the Customer class for use in a data grid. For example, maybe this special Customer object would have a property TotalOrders, which is actually calculated using a join with a collection of Order entities. My question is, what do I call this special Customer class? In other situations, I'd be tempted to call it a CustomerViewModel, but I feel like "overloading" the notion of a view-model like this would be confusing in an MVVM project. What would you suggest?

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  • Warning that users of the function must handle

    - by Hagai
    I am looking for a way to set warning that the user will have to respond. In a sense I would like to use late exception mechanize that occur after the function already finished executing.and returned the wanted value. SomeObject Foo(int input) { SomeObject result; // do something. oh, we need to warn the user. return result; } void Main() { SomeObject object; object = Foo(1); // after copy consturctor is done I would like an exception to be thrown } EDIT: The title to users of the function

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  • how to set title within content page asp.net

    - by varshney4u
    Hi, I have created a Content Page using Master Page. Within Master Page, I have created the following tag for Title: <head id="Head1" runat="server"> <title></title> <meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" /> </head> Within Content Page, following are set: protected void Page_Load(object sender, EventArgs e) { if (!Page.IsPostBack) { if (String.IsNullOrEmpty(Request.QueryString["PatientRegistrationKey"])) { // .... } else { this.Page.Title = "My New Title"; //.... } } Though I am also setting the Master Page at run time as bellow: protected void Page_PreInit(Object sender, EventArgs e) { if (String.IsNullOrEmpty(Request.QueryString["PatientRegistrationKey"])) this.MasterPageFile = "~/MasterPages/A.master"; else this.MasterPageFile = "~/MasterPages/B.master"; } While getting open this page in browser, I got following Title: http://localhost:3562/?PatientRegistrationKey=0 - My New Title Please advice for the changes, so that there should be only My New Title within title, nothing extra like query string etc. Any help would be appreciated.

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  • Check the cumulative status of onLoadInit in a for statement

    - by jonobr1
    In a setup like this is it possible to check the cumulative status of all onLoadInit? for(var i:Number = 0; i < limit; i++) { var mcLoader:MovieClipLoader = new MovieClipLoader(); var mclListener:Object = new Object(); mclListener.onLoadInit = function(mc:MovieClip) { trace(i + " is finished loading!"); } mcLoader.addListener(mclListener); mcLoader.loadClip(some_image_path, someMovieClip); } Initially I was thinking that I could pass an array of Boolean's, but I'm not really sure where to add that checkpoint, because a flash frame doesn't keep looping. Would I have to add it to an onEnterFrame()?

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  • How to create an image from canvas data?

    - by Jakub Hampl
    In my application I am trying to save an arbitrary part of a rendered HTML canvas to an image file. In my Javascript I call ctx.getImageData(x, y, w, h) and pass the resulting object to my macruby code (though if you know a solution in objc I am also very interested). There I'm trying to create a NSBitmapImageRep object so that I can then save to an image format the user desires. This is my code so far (the function gets a WebScriptObject as it's argument): def setimagedata(d) w = d.valueForKey("width").to_i h = d.valueForKey("height").to_i data = Pointer.new(:char, d.valueForKey("data").valueForKey("length").to_i) d.valueForKey("data").valueForKey("length").to_i.times do |i| data[i] = d.valueForKey("data").webScriptValueAtIndex(i).to_i end puts "data complete" # get's called @exported_image = NSBitmapImageRep.alloc.initWithBitmapDataPlanes(data, pixelsWide: w, pixelsHigh:h, bitsPerSample: 32, samplesPerPixel: 4, hasAlpha: true, isPlanar: false, colorSpaceName: NSCalibratedRGBColorSpace, bitmapFormat: NSAlphaNonpremultipliedBitmapFormat, bytesPerRow: 0, bitsPerPixel: 0) puts "done" # doesn't get called end The code doesn't seem to get through the initWithBitmapDataPlanes function but gives no error. My question is: what am I doing wrong? Is this approach reasonable (if not, what would be better?).

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