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  • C++: Static variable inside a constructor, are there any drawbacks or side effects?

    - by doc
    What I want to do: run some prerequisite code whenever instance of the class is going to be used inside a program. This code will check for requiremts etc. and should be run only once. I found that this can be achieved using another object as static variable inside a constructor. Here's an example for a better picture: class Prerequisites { public: Prerequisites() { std::cout << "checking requirements of C, "; std::cout << "registering C in dictionary, etc." << std::endl; } }; class C { public: C() { static Prerequisites prerequisites; std::cout << "normal initialization of C object" << std::endl; } }; What bothers me is that I haven't seen similar use of static variables so far. Are there any drawbacks or side-effects or am I missing something? Or maybe there is a better solution? Any suggestions are welcome.

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  • Java: How ArrayList memory management

    - by cka3o4nik
    In my Data Structures class we have studies the Java ArrayList class, and how it grows the underlying array when a user adds more elements. That is understood. However, I cannot figure out how exactly this class frees up memory when lots of elements are removed from the list. Looking at the source, there are three methods that remove elements: [code] public E remove(int index) { RangeCheck(index); modCount++; E oldValue = (E) elementData[index]; int numMoved = size - index - 1; if (numMoved 0) System.arraycopy(elementData, index+1, elementData, index, numMoved); elementData[--size] = null; // Let gc do its work return oldValue; } public boolean remove(Object o) { if (o == null) { for (int index = 0; index < size; index++) if (elementData[index] == null) { fastRemove(index); return true; } } else { for (int index = 0; index < size; index++) if (o.equals(elementData[index])) { fastRemove(index); return true; } } return false; } private void fastRemove(int index) { modCount++; int numMoved = size - index - 1; if (numMoved 0) System.arraycopy(elementData, index+1, elementData, index, numMoved); elementData[--size] = null; // Let gc do its work } {/code] None of them reduce the datastore array. I even started questioning if memory free up ever happens, but empirical tests show that it does. So there must be some other way it is done, but where and how? I checked the parent classes as well with no success.

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  • Cannot Resize DIV to anything smaller than maximum width

    - by MxmastaMills
    Quick CSS Question. I cannot seem to figure out a very simple CSS/HTML problem. Here's a JSFiddle. http://jsfiddle.net/BmM6t/ Basically, these two divs are not resizing to anything less than 100% width: <div id="main_pic" class="main_div"> THIS IS WHERE THE MAIN PIC WILL GO. </div> <div id="signin" class="main_div"> SIGN IN TO THE SITE! <form> <label for="name">EMAIL/USERNAME:</label> <input type="text" name="name" id="name"> <label for="email">PASSWORD:</label> <input type="text" name="email" id="email"> <br /> <input type="submit" value="Let's Play!"> </form> </div> You'll see that the two divs with class main_div actually take up the entire width of the screen for some reason (you can see that if you inspect the element) even though their widths are clearly written. When you try to change the width of one of the main_div's it changes the width but if you inspect the element, it just changes the width of the object and adds padding around it to make sure it still takes up the entire width of the screen. I'm sure it's some little error I've made but I can't find it. Thanks for the help!

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  • Is there anyway to show a hidden div in the last row of a html table

    - by oo
    i have an html table. here is a simplified version: <table> <tr> <td><div style="display: none;" class="remove0">Remove Me</div></td> </tr> <tr> <td><div style="display: none;" class="remove1">Remove Me</div></td> </tr> <tr> <td><div class="remove2">Remove Me</div></td> </tr> </table> i have javascript that clicks on Remove Me in the last row and it deletes the html row using: $(this).parents("tr:first").remove(); the issue is that when i remove this last row, i also want the "Remove Me" text to now show up on the second row (which is now the new last row). how would i show this div so that it would dynamically show the "remove me" from the new last row?

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  • An Array returned by a model association is not an Array?

    - by Warren
    We have a model association that looks something like this: class Example < ActiveRecord::Base has_many :others, :order => 'others.rank' end The rank column is an integer type. The details of these particular models are not really important though as we have found the same problem with other has_many associations between other models. We have also added to the Enumerable module: module Enumerable def method_missing(name) super unless name.to_s[0..7] == 'collect_' method = name.to_s[8..-1] collect{|element| element.send(method)} end end This adds a collect_id method that we can use to get an array of record ids from an array of ActiveRecord objects. So if we use a normal ActiveRecord find :all, we get a nice array which we can then use collect_id on but if we use Example.others.collect_id, we get NoMethodError: undefined method `collect_id' for #<Class:0x2aaaac0060a0> Example.others.class returns "Array" so is it lying or confused? Our solution thus far has been to use it this way: Example.others.to_a.collect_id This works but this seems a bit strange. Why would you have to do that? We are on Ruby 1.8.7 and Rails 2.3.4

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  • Overlaying several CLR reference fields with each other in explicit struct?

    - by thr
    Edit: I'm well aware of that this works very well with value types, my specific question is about using this for reference types. I've been tinkering around with structs in .NET/C#, and I just found out that you can do this: using System; using System.Runtime.InteropServices; namespace ConsoleApplication1 { class Foo { } class Bar { } [StructLayout(LayoutKind.Explicit)] struct Overlaid { [FieldOffset(0)] public object AsObject; [FieldOffset(0)] public Foo AsFoo; [FieldOffset(0)] public Bar AsBar; } class Program { static void Main(string[] args) { var overlaid = new Overlaid(); overlaid.AsObject = new Bar(); Console.WriteLine(overlaid.AsBar); overlaid.AsObject = new Foo(); Console.WriteLine(overlaid.AsFoo); Console.ReadLine(); } } } Basically circumventing having to do dynamic casting during runtime by using a struct that has an explicit field layout and then accessing the object inside as it's correct type. Now my question is: Can this lead to memory leaks somehow, or any other undefined behavior inside the CLR? Or is this a fully supported convention that is usable without any issues? I'm aware that this is one of the darker corners of the CLR, and that this technique is only a viable option in very few specific cases.

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  • Which design pattern fits - strategy makes sense ?

    - by user554833
    --Bump *One desperate try to get someone's attention I have a simple database table that stores list of users who have subscribed to folders either by email OR to show up on the site (only on the web UI). In the storage table this is controlled by a number(1 - show on site 2- by email). When I am showing in UI I need to show a checkbox next to each of folders for which the user has subscribed (both email & on site). There is a separate table which stores a set of default subscriptions which would apply to each user if user has not expressed his subscription. This is basically a folder ID and a virtual group name. But, Email subscriptions do not count for applying these default groups. So if no "on site" subscription apply default group. Thats the rule. How about a strategy pattern here (Pseudo code) Interface ISubscription public ArrayList GetSubscriptionData(Pass query object) Public class SubscriptionWithDefaultGroup Implement ArrayList GetSubscriptionData(Pass query object) Public class SubscriptionWithoutDefaultGroup Implement ArrayList GetSubscriptionData(Pass query object) Public class SubscriptionOnlyDefaultGroup Implement ArrayList GetSubscriptionData(Pass query object) does this even make sense? I would be more than glad for receive any criticism / help / notes. I am learning. Cheers

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  • C# and ASP.NET MVC: Using #if directive in a view

    - by Mega Matt
    Hi all, I've got a conditional compilation symbol I'm using called "RELEASE", that I indicated in my project's properties in Visual Studio. I want some particular CSS to be applied to elements when the RELEASE symbol is defined, and I was trying to do that from the view, but it doesn't seem to be working. My view code looks like this (shortened a bit for demo purposes): <% #if (RELEASE) %> <div class="releaseBanner">Banner text here</div> <% #else %> <div class="debugBanner">Banner text here</div> <% #endif %> With this code, and with the RELEASE symbol set, the 'else' code is running and I'm getting a div with the debugBanner class. So it doesn't seem to think that RELEASE is defined. It's worth noting that my actual C# code in .cs files is recognizing RELEASE and runs the correct code. It's only the view that is giving me the problem. Does anyone have any insight into this? Any help would be appreciated. Thanks.

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  • How can I differentiate two different touches on a layer ?

    - by srikanth rongali
    I am writing an app in cocos2d. I hava a sprite and a text in my scene. I have written two separate classes for sprite and text. And I added both of them to another class. In sprite class I have written - (void)ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event And in text class I have written -(void) registerWithTouchDispatcher { [[CCTouchDispatcher sharedDispatcher]addTargetedDelegate:self priority:0 swallowsTouches:YES]; } -(BOOL) ccTouchBegan:(UITouch *)touch withEvent:(UIEvent *)event { return YES; } -(void) ccTouchEnded:(UITouch *)touch withEvent:(UIEvent *)event { NSLog(@"Recognized tOuches in Instructions");// CGSize windowSize = [[CCDirector sharedDirector] winSize]; CCNode *node = [self getChildByTag:kTagNode]; [node setPosition: ccp(text1.contentSize.width/2,text1.contentSize.height/2 - windowSize.height)]; } -(void) ccTouchMoved:(UITouch *)touch withEvent:(UIEvent *)event { CGPoint touchLocation = [touch locationInView: [touch view]]; CGPoint prevLocation = [touch previousLocationInView: [touch view]]; touchLocation = [[CCDirector sharedDirector] convertToGL: touchLocation]; prevLocation = [[CCDirector sharedDirector] convertToGL: prevLocation]; CGPoint diff = ccpSub(touchLocation,prevLocation); CCNode *node = [self getChildByTag:kTagNode]; CGPoint currentPos = [node position]; [node setPosition: ccpAdd(currentPos, diff)]; } But, only touches in the text are recognized and touch of sprite is not recognized ? How can I differentiate the two touches.

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  • How can I achieve this kind of relationship (inheritance, composition, something else)?

    - by Tim
    I would like to set up a foundation of classes for an application, two of which are person and student. A person may or may not be a student and a student is always a person. The fact that a student “is a” person led me to try inheritance, but I can't see how to make it work in the case where I have a DAO that returns an instance of person and I then want to determine if that person is a student and call student related methods for it. class Person { private $_firstName; public function isStudent() { // figure out if this person is a student return true; // (or false) } } class Student extends Person { private $_gpa; public function getGpa() { // do something to retrieve this student's gpa return 4.0; // (or whatever it is) } } class SomeDaoThatReturnsPersonInstances { public function find() { return new Person(); } } $myPerson = SomeDaoThatReturnsPersonInstances::find(); if($myPerson->isStudent()) { echo 'My person\'s GPA is: ', $myPerson->getGpa(); } This obviously doesn't work, but what is the best way to achieve this effect? Composition doesn't sond right in my mind because a person does not “have a” student. I'm not looking for a solution necessarily but maybe just a term or phrase to search for. Since I'm not really sure what to call what I'm trying to do, I haven't had much luck. Thank you!

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  • creating a vector with references to some of the elements of another vector

    - by memC
    hi, I have stored instances of class A in a std:vector, vec_A as vec_A.push_back(A(i)). The code is shown below. Now, I want to store references some of the instances of class A (in vec_A) in another vector or another array. For example, if the A.getNumber() returns 4, 7, 2 , I want to put a reference to that instance of A in another vector, say std:vector<A*> filtered_A or an array. Can someone sow me how to do this?? Thanks! class A { public: int getNumber(); A(int val); ~A(){}; private: int num; }; A::A(int val){ num = val; }; int A::getNumber(){ return num; }; int main(){ int i =0; int num; std::vector<A> vec_A; for ( i = 0; i < 10; i++){ vec_A.push_back(A(i)); } std::cout << "\nPress RETURN to continue..."; std::cin.get(); return 0; }

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  • Show Color Picker Value Code Within Input Text Field in Wordpress

    - by Shwan Namiq
    Hi i have options page for my theme i used color picker jquery plugin in my options page as show in image below. i want when i change the color from color picker automatically show the color value code within the text field.how can do this? this is the code within my options page related to appearing the color picker and text field function to register the options setting function YPE_register_settings_sections_fields() { register_setting ( 'YPE_header_option_group', 'YPE_header_option_name', 'YPE_sanitize_validate_callback' ); add_settings_section ( 'YPE_header_section', 'Header Section', 'YPE_header_section_callback', 'YPE_menu_page_options' ); add_settings_field ( 'YPE_header_bg', 'Header Background', 'YPE_header_bg_callback', 'YPE_menu_page_options', 'YPE_header_section' ); } add_action('admin_init', 'YPE_register_settings_sections_fields'); function to appear the text field and color picker function YPE_header_bg_callback() { $YPE_options = get_option('YPE_header_option_name'); $YPE_header_bg = isset($YPE_options['YPE_header_bg']) ? $YPE_options['YPE_header_bg'] : ''; ?> <div class="input-group color-picker"> <input class="form-control" style="width:80px;" name="YPE_header_option_name[YPE_header_bg]" id="<?php echo 'YPE_header_bg'; ?>" type="text" value="<?php echo $YPE_header_bg; ?>" /> <span class="input-group-btn"> <div id="colorSelector"> <div nam style="background-color: #0000ff"> </div> </div> </span> </div> <script> $("#colorSelector").ColorPicker({ color: '#0000ff', onShow: function (colpkr) { $(colpkr).fadeIn(500); return false; }, onHide: function (colpkr) { $(colpkr).fadeOut(500); return false; }, onChange: function (hsb, hex, rgb) { $('#colorSelector div').css('backgroundColor', '#' + hex); }); </script> <?php }

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  • My code is really slow in IE8. But in Safari,firefox,chrome it works great.

    - by bamic01
    Hello all, iam stuck now, i really hope if somebody can tell me the problems what i really don't see. The problem is is the menubar works great in Safari,FF,Chrome. But when i open IE8 its so slow when i put my mouse cursor on another menu area. Or better the entire menu is just so slow! html id & class are <div class="oe_wrapper"> <ul id="oe_menu" class="oe_menu"> this is my javascript code: $(function () { var $oe_menu = $('#oe_menu'); var $oe_menu_items = $oe_menu.children('li'); var $oe_overlay = $('#oe_overlay'); $oe_menu_items.bind('mouseenter', function () { var $this = $(this); $this.addClass('slided selected'); $this.children('div').css('z-index', '9999').stop(true, true).slideDown(300, function () { $oe_menu_items.not('.slided').children('div').hide(); $this.removeClass('slided'); }); }).bind('mouseleave', function () { var $this = $(this); $this.removeClass('selected').children('div').css('z-index', '1'); }); $oe_menu.bind('mouseenter', function () { var $this = $(this); $this.addClass('hovered'); }).bind('mouseleave', function () { var $this = $(this); $this.removeClass('hovered'); $oe_menu_items.children('div').hide(); }) });

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  • Waiting for thread to finish Python

    - by lunchtime
    Alright, here's my problem. I have a thread that creates another thread in a pool, applies async so I can work with the returned data, which is working GREAT. But I need the current thread to WAIT until the result is returned. Here is the simplified code, as the current script is over 300 lines. I'm sure i've included everything for you to make sense of what I'm attempting: from multiprocessing.pool import ThreadPool import threading pool = ThreadPool(processes=1) class MyStreamer(TwythonStreamer): #[...] def on_success(self, data): #### Everytime data comes in, this is called #[...] #<Pseudocode> if score >= limit if list exists: Do stuff elif list does not exist: #</Pseudocode> dic = [] dic.append([k1, v1]) did = dict(dic) async_result = pool.apply_async(self.list_step, args=(did)) return_val = async_result.get() slug = return_val[0] idd = return_val[1] #[...] def list_step(self, *args): ## CREATE LIST ## RETURN 2 VALUES class threadStream (threading.Thread): def __init__(self, auth): threading.Thread.__init__(self) self.auth = auth def run(self): stream = MyStreamer(auth = auth[0], *auth[0]) stream.statuses.filter(track=auth[1]) t = threadStream(auth=AuthMe) t.start() I receive the results as intended, which is great, but how do I make it so this thread t waits for the async_result to come in?? My problem is everytime new data comes in, it seems that the ## CREATE LIST function is called multiple times if similar data comes in quickly enough. So I'm ending up with many lists of the same name when I have code in place to ensure that a list will never be created if the name already exists. So to reiterate: How do I make this thread wait on the function to complete before accepting new data / continuing. I don't think time.sleep() works because on_success is called when data enters the stream. I don't think Thread.Join() will work either since I have to use a ThreadPool.apply_async to receive the data I need. Is there a hack I can make in the MyStreamer class somehow? I'm kind of at a loss here. Am I over complicating things and can this be simplified to do what I want?

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  • Limiting a search to records from last_request_at...

    - by bgadoci
    I am trying to figure out how to display a count for records that have been created in a table since the last_request_at of a user. In my view I am counting the notes of a question with the following code: <% unless @questions.empty? %> <% @questions.each do |question| %> <%= h(question.notes.count) %> end end This is happening in the /views/users/show.html.erb file. Instead of counting all the notes for the question, I would only like to count the notes that have been created since the users last_request_at datetime. I don't neccessarily want to scope notes to display this 'new notes' count application wide, just simply in this one instance. To accomplish I am assuming I need to create a variable in the User#show action and call it in the view but not really sure how to do that. Other information you may need: class Note < ActiveRecord::Base belongs_to :user belongs_to :question end class Question < ActiveRecord::Base has_many :notes, :dependent => :destroy belongs_to :user end

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  • Need help configuring Castle-Windsor

    - by Jonathas Costa
    I have these base interfaces and providers in one assembly (Assembly1): public interface IEntity { } public interface IDao { } public interface IReadDao<T> : IDao where T : IEntity { IEnumerable<T> GetAll(); } public class NHibernate<T> : IReadDao<T> where T : IEntity { public IEnumerable<T> GetAll() { return new List<T>(); } } And I have this implementation inside another assembly (Assembly2): public class Product : IEntity { public string Code { get; set; } } public interface IProductDao : IReadDao<Product> { IEnumerable<Product> GetByCode(string code); } public class ProductDao : NHibernate<Product>, IProductDao { public IEnumerable<Product> GetByCode(string code) { return new List<Product>(); } } I want to be able to get IRead<Product> and IProductDao from the container. I am using this registration: container.Register( AllTypes.FromAssemblyNamed("Assembly2") .BasedOn(typeof(IReadDao<>)).WithService.FromInterface(), AllTypes.FromAssemblyNamed("Assembly1") .BasedOn(typeof(IReadDao<>)).WithService.Base()); The IReadDao<Product> works great. The container gives me ProductDao. But if I try to get IProductDao, the container throws ComponentNotFoundException. How can I correctly configure the registration?

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  • Running Java Program linking to thirdpary library (java -jar) issue ( Multiple methods tried )

    - by bamachrn
    This issue is related to running a Java program (jar) dependent on thirdparty jar library even after setting classpath and trying so many other methods by reading articles in Internet. I want to use a thirdparty Pack1.jar (it is not a part of jvm) as dependency of my programme. I do not know where the Pack1.jar file could be in the deployment machine and I want the deployer to specify the path for the thirdparty libraries I have tried the following alternatives in vain Setting the java.class.path programatically String class_path = args[0]; System.setProperty("java.class.path",class_path); Here I am assuming that deployer would supply the classpath as first argument while running the program Setting the CLASSPATH env_var to locate the thirdparty directory While running, using the classpath option java -classpath /path/to/Pack1.jar -jar Pack2.jar I think this would not work because documentation says that classpath is ignored when program is run with "java -jar" Setting the java.ext.dirs programatically. Setting the java.library.path programatically. I do not want to specify the Class-Path in manifest because that takes only relative path and I do not know where the thirdparty library would be kept in deployment machine But I am unable to get the jar running. How can I fix this problem any help please.

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  • Disallow taking pointer/reference to const to a temporary object in C++ (no C++0X)

    - by KRao
    Hi, I am faced with the following issue. Consider the following class: //Will be similar to bost::reference_wrapper template<class T> class Ref { public: explicit Ref(T& t) : m_ptr(&t) {} private: T* m_ptr; }; and this function returning a double double fun() {return 1.0;} If we now have double x = 1.0; const double xc = 1.0; Ref<double> ref1(x); //OK Ref<const double> refc1(cx); //OK good so far, however: //Ref<double> ref2( fun() ); //Fails as I want it to Ref<const double> refc2( fun() ); //Works but I would like it not to Is there a way to modify Ref (the way you prefer) but not the function fun, so that the last line returns a compile-time error? Please notice you can modify the constructor signature (as long as I am able to initialise the Ref as intended). Thank you in advance for your help!

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  • Android thread handler NullPointerException

    - by Realn0whereman
    So this null pointer is confusing me. I believe it is a scope issue. My main activity looks like this: public class App extends Activity { ProgressDialog progressDialog; ProgressThread progressThread; Then inside of the oncreate I do this: ProgressDialog progressDialog = new ProgressDialog(this); progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER); progressDialog.setMessage("Fetching Images..."); ProgressThread progressThread = new ProgressThread(handler,mImageIds,mImages); progressThread.start(); progressDialog.show(); THEN inside progressThread which is a separate class I do mHandler.sendMessage(mHandler.obtainMessage()); Now up until this point i believe it behaves as it should. I have my handler hanging out in class scope right underneath my oncreate final Handler handler = new Handler() { public void handleMessage(Message msg){ progressDialog.hide(); progressThread.interrupt(); } }; The program thinks that progressDialog and progressThread are declared, but are null. Why would they be null if I instantiate in my oncreate.

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  • How to create reference tables using fluent nhibernate

    - by Akk
    How can i create a 3 table schema from the following model classes. public class Product { public int Id {get; set;} public string Name {get; set;} public IList<Photo> Photos {get; set;} } public class Photo { public int Id {get; set;} public string Path {get; set;} } I want to create the following table structure in the database: Product ------- Id Name ProductPhotos ------------- ProductId (FK Products.Id) PhotoId (FK Photos.Id) Photos ------ Id Path How i can express the above Database Schema using Fluent NHibernate? I could only manage the following the Mapping but this does not get me the 3rd Photo ref table. public class ProductMap : ClassMap<Product> { public CityMap() { Id(x => x.Id); Map(x => x.Name); Table("Products"); HasMany(x => x.Photos).Table("ProductPhotos").KeyColumn("ProductId"); } }

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  • How can I order my entries by sum from a separate table?

    - by bgadoci
    I am wondering how I can order posts in my PostController#index to display by a column total in a separate table. Here is how I have it set up. class Post < ActiveRecord::Base :has_many :votes end and Class Vote < ActiveRecord::Base :belongs_to :post end I user can either vote up or down a particular post. I know there are likely better ways to do what I am currently doing but looking for a fix given my current situation. When a user votes up a post, a value of 1 is passed to the Vote Table via a hidden field. When a user votes down a post a value of -1 is passed to the same column (names vote). I am wondering how I can display my posts in order of the sum of the vote column (in the vote table) for a particular post. Another way to say that is, if a particular post has a net vote sum of 5, I want that to appear above a post with a net vote sum of 4. I am assuming that I need to affect the PostController#index action in some fashion. But not sure how to do that.

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  • WPF binding problem

    - by Lolo
    I've got problem with binding in XAML/WPF. I created Action class witch extends FrameworkElement. Each Action has list of ActionItem. The problem is that the Data/DataContext properties of ActionItem are not set, so they are always null. XAML: <my:Action DataContext="{Binding}"> <my:Action.Items> <my:ActionItem DataContext="{Binding}" Data="{Binding}" /> </my:Action.Items> </my:Action> C#: public class Action : FrameworkElement { public static readonly DependencyProperty ItemsProperty = DependencyProperty.Register("Items", typeof(IList), typeof(Action), new PropertyMetadata(null, null), null); public Action() { this.Items = new ArrayList(); this.DataContextChanged += (s, e) => MessageBox.Show("Action.DataContext"); } public IList Items { get { return (IList)this.GetValue(ItemsProperty); } set { this.SetValue(ItemsProperty, value); } } } public class ActionItem : FrameworkElement { public static readonly DependencyProperty DataProperty = DependencyProperty.Register("Data", typeof(object), typeof(ActionItem), new PropertyMetadata( null, null, (d, v) => { if (v != null) MessageBox.Show("ActionItem.Data is not null"); return v; } ), null ); public object Data { get { return this.GetValue(DataProperty); } set { this.SetValue(DataProperty, value); } } public ActionItem() { this.DataContextChanged += (s, e) => MessageBox.Show("ActionItem.DataContext"); } } Any ideas?

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  • sending address of a variable declared on the stack?

    - by kobac
    I have a doubt concerning declaring variables, their scope, and if their address could be sent to other functions even if they are declared on the stack? class A{ AA a; void f1(){ B b; aa.f2(&b); } }; class AA{ B* mb; f2(B* b){ mb = b; //... } }; Afterwards, I use my AA::mb pointer in the code. So things I would like to know are following. When the program exits A::f1() function, b variable since declared as a local variable and placed on the stack, can't be used anymore afterwards. What happens with the validity of the AA::mb pointer? It contains the address of the local variable which could not be available anymore, so the pointer isn't valid anymore? If B class is a std::<vector>, and AA::mb is not a pointer anymore to that vector, but a vector collection itself for example. I would like to avoid copying all of it's contents in AA::f2() to a member AA::mb in line mb = b. Which solution would you recommend since I can't assign a pointer to it, because it'll be destroyed when the program exits AA::f2()

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  • Image on mouseover takes space on PageLoad.

    - by Ram
    Hello, I am trying to show an image on Mouseover and hide it on Mouseout. I am successful in mouseover and mouseout but the image is actually taking the space around the text though i have visibility as hidden.. The text is surrounded with the space of image but the image is displayed on mouseover. Here is the code: <td valign="middle" class="table_td td top" style="width: 347px"> <div id="Style16" style="position:relative; height:100%; left:50%; bottom:700%; visibility:hidden; border:solid 0px #CCC; padding:5px"><img src="images/window-decal-image.gif"></div> <span class="feature_text" style="cursor:pointer" onmouseover="ShowPicture('Style16',1)" onmouseout="ShowPicture('Style16',0)" id="a16">Storefront Window Decal</span> <span class="feature_text_small">(5"x3.5" double sided decal)</span></td> <script language="javascript" type="text/javascript"> function ShowPicture(id,Source) { var vis, elem; if (1 == Source) { vis = "visible"; } else if (0 == Source) { vis = "hidden"; } else { throw new RangeError("Unknown Flag"); } if (elem = document.getElementById(id)) { elem.style.visibility = vis; } else { throw new TypeError("Element with id '"+id+"' does not exist."); } return vis; } </script>

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  • Triangulation in 3D Space

    - by w3b_wizzard
    Disclaimer: This is for class, however I'm fresh out of ideas and a nudge in the right direction would be much appreciated. Also, this needs to be implemented in raw C, so no fancy libraries can be used. I have to write a search and rescue simulator for submarines, it has to find a probe that is randomly placed in 3D space in a grid from of the MAX_XYZ (100000). The only tools I'm given are a "ping" which will give the magnitude of the distance between a certain sub and the probe. The goal is to optimize the costs of this entire operation so a brute force attempt, like looking at every single coordinate, won't work. Hence I was thinking triangulation. Now, it makes loads of sense to me, place three subs, each one of them uses their ping to get the distance between them and the probe. Since each sub have a known distance relative to one another, it's easy to build the base of a tetrahedron with them, and the results of the ping will point to a certain coordinate, the problem I'm having is how to figure out the elevation, or the height, of the tetrahedron. So what I have as data is the following: Distances between subs (In vector format) Angles between each subs (very easy to compute) Distance between each sub and the probe (3 segments from the base to the peak) Angles inside each of the outer 3 surfaces of the tetrahedron. I tried finding some sort of relationship with the vertices of the tetrahedron and the relative angles in each of them, however all I found had to deal with tetrahedrons built with equilateral triangles, which isn't much help. I have the impression this can be easily solved with trig but either I'm not seeing it or I need more coffee. Any suggestions would be appreciated!

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