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  • Difference between var and Class class in object creation

    - by Divine
    Its a silly question, however shocked to see different behaviors. Learning a lot. Lets say I have two classes below Class A { public void Display() { } } Class B : A { public void Display() { } } Class C : B { public void Display() { } } Class Final { static void Main() { var c = new C(); // B c = new C(); //My doubt is, both of the above gives different results. May I know B c = new C() creates object of B or C? What I understood is, it creates object of B. Then why we say "new C()"? I agree with C c = new C(); But I thought, B b = new C(); creates object of B. Where we use this style? Only when utilizing runtime polymorphism? (Overriding methods)? } }

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  • How to bind to current riacontext user in xaml

    - by Jakob
    Hi. I Have a datacontext that has a "getuserbyguid" method, i want to pass in the current logged in user.userid as a parameter, but I don't know how to bind to the current logged in user through xaml. I've tried {Binding Path=User.UserId} but without any luck. I'm using the built in riaservices authentication methods, so the userinfo should be exposed in the riacontext, or am I wrong about this? I have this for instance <riaControls:DomainDataSource x:Name="FollowingGridData" AutoLoad="True" QueryName="GetUsersFollowedByIDQuery" LoadSize="20"> <riaControls:DomainDataSource.DomainContext> <my:NotesDomainContext /> </riaControls:DomainDataSource.DomainContext> <riaControls:DomainDataSource.QueryParameters> <riaControls:Parameter ParameterName="userguid" Value="{Binding Path=User.UserId}" /> </riaControls:DomainDataSource.QueryParameters> </riaControls:DomainDataSource> But it gives me an error saying that it's not a guid, meaning that it must not be binding correctly

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  • C++ Singleton design pattern.

    - by Artem Barger
    Recently I've bumped into realization/implementation of Singleton design pattern for C++. It has looked in the following way (I have adopted it from real life example): // a lot of methods is omitted here class Singleton { public: static Singleton* getInstance( ); ~Singleton( ); private: Singleton( ); static Singleton* instance; }; From this declaration I can deduce that instance field is initiated on the heap, that means there is a memory allocation. That is completely unclear for me is when does exactly memory is going to be deallocated? Or there is a bug and memory leak? It seems like there is a problem in implementation. PS. And main question how to implement it in the right way?

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  • Magento and unsetting a custom boolean attribute

    - by Spongeboy
    Hi, I've added an attribute to a customer address entity. Attribute setup code is as follows- 'entity_type_id'=>$customer_address_type_id, 'attribute_code'=>'signature_required', 'backend_type'=>'int', 'frontend_input'=>'boolean', 'frontend_label' => 'Signature required', 'is_global' => '1', 'is_visible' => '1', 'is_required' => '0', 'is_user_defined' => '0', I have then - added attribute to model\entity\setup.php added a HTML field on the edit form I am now getting the attribute saved to the database when the checkbox is checked. However, it is not being unset when checkbox is unchecked (I'm guessing due to checkbox input not being 'post'-ed if unchecked. What is the best way to uncheck this? Should I add a default value of 0? Or unset/delete the attribute before save in the controller? Should I add get/set methods to the model?

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  • Javascript data parsing in IE vs other browsers... It seems kinda screwed up. What's the deal?

    - by Carter
    Firstly, when I say other browsers I really only mean Firefox because that's all I tested in. Internet Explorer can parse a date followed by a single character as a proper date. Whereas Firefox behaves as I'd expect. For example... var dateString = new Date("1/1/2010f"); alert(dateString); In IE it will alert... Thu Dec 31 21:00:00 UTC-0900 2009 Whereas in FF is will spit out... "Invalid Date" I first noticed this using the jquery validation plug in. http://docs.jquery.com/Plugins/Validation/Methods/date It seems like it just subtracts some amount of hours off the actual date in IE when a character is appended. I've tested in IE6 and IE8. Am I missing something?

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  • Is select() Ok to implement single socket read/write timeout ?

    - by chmike
    I have an application processing network communication with blocking calls. Each thread manages a single connection. I've added a timeout on the read and write operation by using select prior to read or write on the socket. Select is known to be inefficient when dealing with large number of sockets. But is it ok, in term of performance to use it with a single socket or are there more efficient methods to add timeout support on single sockets calls ? The benefit of select is to be portable.

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  • What is the MVC version of this code?

    - by Ian Boyd
    i'm trying to wrap my head around how to enterprise up my code: taking a simple routine and splitting it up into 5 or 6 methods in 3 or 4 classes. i quickly came up three simple examples of code how i currently write it. Could someone please convert these into an MVC/MVP obfuscated version? Example 1: The last name is mandatory. Color the text box red if nothing is entered. Color it green if stuff is entered: private void txtLastname_TextChanged(object sender, EventArgs e) { //Lastname mandatory. //Color pinkish if nothing entered. Greenish if entered. if (txtLastname.Text.Trim() == "") { //Lastname is required, color pinkish txtLastname.BackColor = ControlBad; } else { //Lastname entered, remove the coloring txtLastname.BackColor = ControlGood; } } Example 2: The first name is optional, but try to get it. We'll add a bluish tint to this "try to get" field: private void txtFirstname_TextChanged(object sender, EventArgs e) { //Firstname can be blank. //Hint them that they should *try* to get it with a bluish color. //If they do enter stuff: it better be not all spaces. if (txtFirstname.Text == "") { //Nothing there, hint it blue txtFirstname.BackColor = ControlRequired; } else if (txtFirstname.Text.Trim() == "") { //They entered spaces - bad user! txtFirstname.BackColor = ControlBad; } else { //Entered stuff, remove coloring txtFirstname.BackColor = SystemColors.Window; } } Example 3 The age is totally optional. If an age is entered, it better be valid: private void txtAge_TextChanged(object sender, EventArgs e) { //Age is optional, but if entered it better be valid int nAge = 0; if (Int32.TryParse(txtAge.Text, out nAge)) { //Valid integer entered if (nAge < 0) { //Negative age? i don't think so txtAge.BackColor = ControlBad; } else { //Valid age entered, remove coloring txtAge.BackColor = SystemColors.Window; } } else { //Whatever is in there: it's *not* a valid integer, if (txtAge.Text == "") { //Blank is okay txtAge.BackColor = SystemColors.Window; } else { //Not a valid age, bad user txtAge.BackColor = ControlBad; } } } Every time i see MVC code, it looks almost like random splitting of code into different methods, classes, and files. i've not been able to determine a reason or pattern to their madness. Without any understanding of they why it's being one some way, it makes no sense. And using the words model, view, controller and presenter, like i'm supposed to know what that means, doesn't help. The model is your data. The view shows data on screen. The controller is used to carry out the users actions And oranges taste orangy. Here's my attempt at splitting things up in order to make the code more difficult to follow. Is this anywhere close to MVC? private void txtFirstname_TextChanged(object sender, EventArgs e) { FirstnameTextChangedHandler(sender, e); } private void FirstnameTextChangedHandler(sender, e) { string firstname = GetFirstname(); Color firstnameTextBoxColor = GetFirstnameTextBoxColor(firstname); SetFirstNameTextBoxColor(firstnameTextBoxColor); } private string GetFirstname() { return txtFirstname.Text; } private Color GetFirstnameTextBoxColor(string firstname) { //Firstname can be blank. //Hint them that they should *try* to get it with a bluish color. //If they do enter stuff: it better be not all spaces. if (firstname == "") { //Nothing there, hint it blue return GetControlRequiredColor(); } else if (firstname.Trim() == "") { //They entered spaces - bad user! return GetControlBadColor(); } else { //Entered stuff, remove coloring return GetControlDefaultColor(); } } private Color GetControlRequiredColor() { return ControlRequired; } private Color GetControlBadColor() { return ControlBad; } private Color GetControlGoodColor() { return ControlGood; } //am i doin it rite i've obfuscated the code, but it's still altogether. The next step in the MVC obfuscation, i gather, is to hide the code in 3 or 4 different files. It's that next step that i don't understand. What is the logical separation of which functions are moved into what other classes? Can someone translate my 3 simple examples above into full fledged MVC obfuscation? Edit: Not ASP/ASP.NET/Online. Pretend it's on a desktop, handheld, surface, kiosk. And pretend it's language agnostic.

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  • Instantiation vs. Typed reference

    - by Farstucker
    Just when I think Im starting to understand the basics, I find something that brings me right back to reality. In this case, typed reference. I found an example similar to this: class Worker { Boss boss; public void Advise(Boss pBoss) { this.boss = pBoss; } How can you reference methods within the Boss class if its not static and not instantiated? I guess my real question is whats the difference between: Boss boss; and Boss boss = new Boss(); Thank you, FS

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  • Migrating Data to MSSQL 2008

    - by Fred Clown
    I am trying to migrate data from an Informix database to MSSQL 2008. I've got quite a lot of data to move. I've been try multiple methods to get the data over, and so far SQLBulkCopy in multiple chunks seems to be the fastest that I can find. Does anyone know of a faster means of getting the data over? I'm trying to cut down on the transfer time so that on my cut-over date I don't run out of time to do the full cut-over. Thanks.

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  • Re-ordering a collection of UIView's based on their CGPoint

    - by Chris
    Hi all, I have a NSMutableArray that holds a collection of UIViewControllers Amongst other properties and methods an instance of each of the viewControllers are placed in a parent view The user will place these objects individually when desired to. So essentially I use - (void)addSubview:(UIView *)view when a new view is added to the parent view controller. Because the UI is isometric it's made things a tad more complicated What I am trying to do is re-order the views based on their co-ordinate position, so items higher up the parent UIView frame is indexed lower then views lower in the parent UIview frame. And items that are on the left side of the view are positioned at a higher index to those on the right I think the solution may have to do with re-ordering the NSMutableArray but how can I compare the CGpoints? Do I need to compare the x and y separately?

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  • Casting objects to Integer,string ,...

    - by Milan
    Hello everybody! I have one small problem. I have list of types(int,string,..) ArrayList<Class> typeList; and I have some input values; ArrayList<Object> values; How to cast some value to some type if I know which type from the typeList is the values; typeList.get(i).cast(values.get(i)); <- this is not working??? Actualy I generate dynamic form in runtime. With Java reflection I get parameterTypes from methods from some class, I generate form with input fields and then i want to cast the text from the input fields to specific types from the paramterTypes that I got with Java reflection from some class.

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  • What is the best method of assessment for computer science students?

    - by Gavimoss
    This question is a bit more philosophical so feel free to remove if you like but it's been bugging me for the last 4 years! As a final year student I find that exams can be often be passed with a couple of days of cramming, without necessarily retaining or understanding the content i.e. a regurgitation of lecture notes is often enough to gain high marks. A friend of mine is about to graduate with an honours degree whose final year evaluation was based solely on practical work (a project, assignment marks and the creation of a poster) yet all of this work could have been completed by a third party. Personally I don't think either of these methods of assessment is sufficient as I am currently on track for a 1st class honours in artificial intelligence and computer science and believe this is mostly due to my skill in passing exams not my skill as a programmer or my vast in depth knowledge of any of the subjects I have "studied". Surely there is a better way to assess our skills - isn't there?

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  • gwt - Using List<Serializable> in a RPC call?

    - by Garagos
    I have a RPC service with the following method: public List<Serializable> myMethod(TransactionCall call) {...} But I get a warning when this method is analyzed, and then the rpc call fails Analyzing 'my.project.package.myService' for serializable types Analyzing methods: public abstract java.util.List<java.io.Serializable> myMethod(my.project.package.TransactionCall call) Return type: java.util.List<java.io.Serializable> [...] java.io.Serializable Verifying instantiability (!) Checking all subtypes of Object wich qualify for serialization It seems I can't use Serializable for my List... I could use my own interface instead (something like AsyncDataInterface, wich implements the Serializable interface) but the fact is that my method will return a list custom objects AND basic objects (such as Strings, int....). So my questions are: Is it a standart behaviour? (I can't figure out why I can't use this interface in that case) Does anyone have a workaround for that kind of situation?

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  • C# - How to convert 10 bytes to unsigned long

    - by Justin
    Hey, I have 10 bytes - 4 bytes of low order, 4 bytes of high order, 2 bytes of highest order - that I need to convert to an unsigned long. I've tried a couple different methods but neither of them worked: Try #1: var id = BitConverter.ToUInt64(buffer, 0); Try #2: var id = GetID(buffer, 0); long GetID(byte[] buffer, int startIndex) { var lowOrderUnitId = BitConverter.ToUInt32(buffer, startIndex); var highOrderUnitId = BitConverter.ToUInt32(buffer, startIndex + 4); var highestOrderUnitId = BitConverter.ToUInt16(buffer, startIndex + 8); return lowOrderUnitId + (highOrderUnitId * 100000000) + (highestOrderUnitId * 10000000000000000); } Any help would be appreciated, thanks!

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  • Creating an interface and swappable implementations in python

    - by Blankman
    Hi, Would it be possible to create a class interface in python and various implementations of the interface. Example: I want to create a class for pop3 access (and all methods etc.). If I go with a commercial component, I want to wrap it to adhere to a contract. In the future, if I want to use another component or code my own, I want to be able to swap things out and not have things very tightly coupled. Possible? I'm new to python.

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  • Java: how to represent graphs?

    - by Rosarch
    I'm implementing some algorithms to teach myself about graphs and how to work with them. What would you recommend is the best way to do that in Java? I was thinking something like this: public class Vertex { private ArrayList<Vertex> outnodes; //Adjacency list. if I wanted to support edge weight, this would be a hash map. //methods to manipulate outnodes } public class Graph { private ArrayList<Vertex> nodes; //algorithms on graphs } But I basically just made this up. Is there a better way? Also, I want it to be able to support variations on vanilla graphs like digraphs, weighted edges, multigraphs, etc.

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  • How to modify posted form data within controller action before sending to view?

    - by Gary
    I want to render the same view after a successful action (rather than use RedirectToAction), but I need to modify the model data that is rendered to that view. The following is a contrived example that demonstrates two methods that that do not work: [AcceptVerbs("POST")] public ActionResult EditProduct(int id, [Bind(Include="UnitPrice, ProductName")]Product product) { NORTHWNDEntities entities = new NORTHWNDEntities(); if (ModelState.IsValid) { var dbProduct = entities.ProductSet.First(p => p.ProductID == id); dbProduct.ProductName = product.ProductName; dbProduct.UnitPrice = product.UnitPrice; entities.SaveChanges(); } /* Neither of these work */ product.ProductName = "This has no effect"; ViewData["ProductName"] = "This has no effect either"; return View(product); } Does anyone know what the correct method is for accomplishing this?

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  • How to use intent between tabs in java/Android?

    - by Praveen Chandrasekaran
    I would need to know how to handle the intent between tabs. For example, I have a tab activity with two tabs. First on content is a text view. another one is a map view. When i click that text view it redirects to the tab2. it can be easily achieved by setCurrentTab(1) or setCurrentTabByTag("tab2") methods. But i want to pass lat and long values to that Map Activity to drop pin. What is the better way to use intents or getter/setter in java? What do you prefer? if your answer is "Intents". How?

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  • Qt: any way to automatically generate QSharedData-based structures?

    - by Eye of Hell
    Hello. Qt has a build-in supprt for creating objects with integrated reference counting via QSharedData and QSharedDataPointer. All wordks great, but for each such object i need to write a lot of code: QSharedData-based implementation class with constructor and copy constructor, object class itsef with accessor methods for each filed. For a simple structures with 5-10 fields this requires really lot of near same code. Is it some ways to automate such classes generation? Maybe it's some generators exists that take a short description and automatically generates implementation class and object class with all accessors?

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  • What is a good way of coding a file processing program, which accepts multisource data in Java

    - by jjepsuomi
    I'm making a data prosessing system, which currently is using csv-data as input and output form. In the future I might want to add support for example database-, xml-, etc. typed input and output forms. How should I desing my program so that it would be easy to add support for new type of data sources? Should simply make for example an abstract data class (which would contain the basic file prosessing methods) and then inherit this class for database, xml, etc. cases? Hope my question is clear =) In other words my question is: "How to desing a file prosessing system, which can be easily updated to accept input data from different sources (database, XML, Excel, etc.)".

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  • Howto disable the emacs site-start files permanently?

    - by elemakil
    When solving this problem I figured out that I need to disable the site-wise init files in order to get my emacs + CEDET running (everything works nicely when starting emacs using emacs --no-site-file but is broken without the additional argument). I'd like to disable the site-wise init files permanently but as I'm using several different approaches/methods when launching emacs (launcher/panel/terminal) I don't think aliasing it in my .zshrc won't work. I require a method to permanently disable all site-start files. Is there any easy way to achieve this? Thanks!

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  • API verbs for an interruptible operation

    - by 280Z28
    I have a long running task as part of my application. The task can be started, paused, resumed, and cancelled. I'm trying to find the best interface for these operations. Two seem clear: Pause and Cancel. This leaves the start and resume operations. I could include both Start and Resume. This has the downside of either requiring the API consumer to check the state before starting/resuming the operation to call the right method, or making the methods aliases of each other. I'm thinking I should include either Start or Resume, but I don't know which one is the most appropriate. Does anyone have any examples in the .NET Framework of such behavior? I prefer to follow established patterns whenever they are available.

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  • jQuery way to handle select lists, radio buttons and checkboxes

    - by Álvaro G. Vicario
    When I handle HTML form elements with jQuery, I always end up with an ugly mix of jQuery syntax and plain JavaScript like, e.g.: function doStuff($combo){ if( $combo.get(0).options[$combo.get(0).selectedIndex].value=="" ){ var txt = ""; }else{ var txt = $combo.get(0).options[$combo.get(0).selectedIndex].text; } var $description = $combo.closest("div.item").find("input[name$=\[description\]]"); $description.val(txt); } Are there standard jQuery methods to handle typical operations on elements like <select>, <input type="radio"> and <input type="checkbox">? With typical, I mean stuff like reading the value of the selected radio button in a group or replacing elements in a selection list. I haven't found them in the documentation but I admit that method overloading can make doc browser kind of tricky.

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  • Method params match signature, but still getting error

    - by Jason
    I am in the midst of converting a VB library to C#. One of my methods has the following signature in VB: Private Shared Sub FillOrder(ByVal row As DataRowView, ByRef o As Order) In C# I converted it to: private static void FillOrder(DataRowView row, ref Order o) From my constructor inside my Order class, I am calling the FillOrder() method like so: DataView dv = //[get the data] if (dv.Count > 0) { FillOrder(dv[0], this); } In VB, this works: Dim dv As DataView = '[get data]' If dv.Count > 0 Then FillOrder(dv.Item(0), Me) End If However, in VS10 in the C# file I am getting a red squiggle under this call with the following error: The best overloaded method match for [the method] has some invalid arguments This was working code in VB. What am I doing wrong?

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  • iPhone: Custom UITableViewCell with multiple areas that respond to taps?

    - by Nick
    I've been asked to create a custom UITableViewCell with multiple areas that can be tapped. These areas won't have buttons or any graphics - they'll be invisible. 3 different methods will be called depending on which third of the cell the user taps i.e. || decrementFooCount || viewFooDetails || incrementFooCount || The cell has a few labels on it that need to be visible at all times - the fooName and fooCount. I'm thinking perhaps three hidden UIButtons over the cell? I also need to maintain the swipe to delete default behavior.

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