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  • C# - Silverlight - Dynamically calling a method

    - by cmaduro
    Is there anyway in C# to call a method based on a Enum and/or class? Say if I were to call Controller<Actions.OnEdit, Customer>(customer); Could I do something like this then? public void Controller<TAction, TParam>(TParam object) { Action<TParam> action = FindLocalMethodName(TAction); action(object); } private Action<T> FindLocalMethodName(Enum method) { //Use reflection to find a metode with //the name corresponding to method.ToString() //which accepts a parameters type T. }

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  • Rails: unexpected behavior updating a shared instance

    - by Pascal Lindelauf
    I have a User object, that is related to a Post object via two different association paths: Post --(has_many)-- comments --(belongs to)-- writer (of type User) Post --(belongs to)-- writer (of type User) Say the following hold: user1.name == "Bill" post1.comments[1].writer == user1 post1.writer == user1 Now when I retrieve the post1 and its comments from the database and I update post1.comments[1].writer like so: post1.comments[1].writer.name = "John" I would expect post1.writer to equal "John" too. But it doesn't! It still equals "Bill". So there seems to be some caching going on, but the kind I would not expect. I would expect Rails to be clever enough to load exactly one instance of the user with name "Bill"; instead is appears to load two individual ones: one for each association path. Can someone explain how this works exactly and how I am to handle these types of situations the "Rails way"?

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  • How can we copy datacolumn with data from one table to another ?

    - by Harikrishna
    I have one Datatable like DataTable addressAndPhones; And there are four columns name,address,phoneno,and other details and I only want two columns Name and address from that so I do for that is DataTable addressAndPhones2; addressAndPhones2.Columns.Add(new DataColumn(addressAndPhones.Columns["name"].ColumnName)); addressAndPhones2.Columns.Add(new DataColumn(addressAndPhones.Columns["address"].ColumnName)); But it gives me error so how can I copy fix no of columns data from one table to another table ? ERROR :Object reference not set to an instance of an object. EDIT : Only column is copied to another table, data of that column is not copied to another table.

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  • Find the right parameters for an event without using Design Mode in Visual Studio 2010

    - by Jason
    Is there a way to know what parameters are needed by an event in Visual Studio 2010? Let's say I have a DropDownList control and I want to bind a method to the "OnSelectedIndexChanged", I would do something like this In the ASPX File: <asp:DropDownList ID="lstMyList" runat="server" OnSelectedIndexChanged="lstMyList_SelectedIndexChanged"></asp:DropDownList> In the codebehind: protected void lstMyList_SelectedIndexChanged(object sender, EventArgs e) { ... } Is there a way to know what parameters the method needs? (In this case, an object for the sender and an EventArgs parameter for the event.) I know you can easily create the method by double-clicking the right event in Design Mode, but it does a mess with your code so I prefer not to use it. Thanks!

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  • Should I use implicit conversions to enforce preconditions?

    - by Malvolio
    It occurs to me that I could use use implicit conversions to both announce and enforce preconditions. Consider this: object NonNegativeDouble { implicit def int2nnd(d : Double) : NonNegativeDouble = new NonNegativeDouble(d) implicit def nnd2int(d : NonNegativeDouble) : Double = d.v def sqrt(n : NonNegativeDouble) : NonNegativeDouble = scala.math.sqrt(n) } class NonNegativeDouble(val v : Double ) { if (v < 0) { throw new IllegalArgumentException("negative value") } } object Test { def t1 = { val d : Double = NonNegativeDouble.sqrt(3.0); printf("%f\n", d); val n : Double = NonNegativeDouble.sqrt(-3.0); } } Ignore for the moment the actual vacuity of the example: my point is, the subclass NonNegativeDouble expresses the notion that a function only takes a subset of the entire range of the class's values. First is this: A good idea, a bad idea, or an obvious idea everybody else already knows about Second, this would be most useful with basic types, like Int and String. Those classes are final, of course, so is there a good way to not only use the restricted type in functions (that's what the second implicit is for) but also delegate to all methods on the underlying value (short of hand-implementing every delegation)?

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  • iPhone - Launching selectors from a different class

    - by David Schiefer
    Hi, I'd like to reload a table view which is in another class called "WriteIt_MobileAppDelegate" from one of my other classes which is called "Properties". I've tried to do this via the NSNotificationCenter class - the log gets called but the table is never updated. Properties.h: [[NSNotificationCenter defaultCenter] postNotificationName:@"NameChanged" object:[WriteIt_MobileAppDelegate class] userInfo:nil]; WriteIt_MobileAppDelegate.m -(void)awakeFromNib { [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reloadItProperties:) name:@"NameChanged" object:self]; } - (void) reloadItProperties: (NSNotification *)notification { NSLog(@"Reloading Data"); //this gets called [self.navigationController popToRootViewControllerAnimated:YES]; [self.tblSimpleTable reloadData]; [self.tblSimpleTable reloadSectionIndexTitles]; // but the rest doesn't } What am I doing wrong here?

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  • jQuery .getJSON() Not Parsing All Objects

    - by Brad
    I'm using jQuery's .getJSON function to parse a set of search results from a Google Search Appliance. The search appliance has an xslt stylesheet that returns the results as JSON data, which I validated with both JSONLint and Curious Concept's JSON Formatter. According to FireBug, the full result set is returned from the XMLHTTPRequest, but I tried dumping the data (with jquery.dump.js) and it only ever parses back the first result. It does successfully get all the Google Search Protocol stuff, but it only ever sees one "R" object (or individual result). Has anybody had a similar problem with jQuery's .getJSON? I know it likes to fail silently if the JSON is not valid, but like I said, I validated the results with several validators and it should be good to go. Edit: Clicking this link will show you the JSON results returned for a search for the word "google": http://bigbird.uww.edu/search?client=json_frontend&proxystylesheet=json_frontend&proxyrefresh=1&output=xml_no_dtd&q=google jQuery only retrieves the first "R" object, even though all "R" objects are siblings.

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  • getJSON for dropbox data

    - by gheil.apl
    Although i used getJSON in http://jsbin.com/dbJSON/edit i have not been able to connect with any of my own made up data. i tried 4, and the example at Flickr for "cats". Only the latter worked... this is the output: {assoc: null,assoc.js: null,stub: null,stub.js: null,cat: [object Object]} i am at that "base", as i did get the image there, but db.tgu.ca/repsychal/poems/10/0512-g2g/assoc.json db.tgu.ca/repsychal/poems/10/0512-g2g/assoc.js db.tgu.ca/repsychal/poems/10/0512-g2g/stub.json db.tgu.ca/repsychal/poems/10/0512-g2g/stub.js were all invisible==null! (they are all URL, just put h t t p //: in front ... a restriction on the # of URL in a post) How do i get "my" data into the page?

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  • Why does $('#id') return true if id doesn't exist?

    - by David
    I always wondered why jQuery returns true if I'm trying to find elements by id selector that doesnt exist in the DOM structure. Like this: <div id="one">one</div> <script> console.log( !!$('#one') ) // prints true console.log( !!$('#two') ) // is also true! (empty jQuery object) console.log( !!document.getElementById('two') ) // prints false </script> I know I can use !!$('#two').length since length === 0 if the object is empty, but it seems logical to me that a selector would return the element if found, otherwise null (like the native document.getElementById does). F.ex, this logic can't be done in jQuery: var div = $('#two') || $('<div id="two"></div>'); Wouldnt it be more logical if the ID selector returned null if not found? anyone?

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  • Only one instance of a scriptmanager can exist on a page

    - by dotnetdev
    Hi, I design an ASP.NET web usercontrol and with a maskeditor and scriptmanager, I always get an object reference not set to an instance of an object exception at runtime. Stacktrace is: [InvalidOperationException: Only one instance of a ScriptManager can be added to the page.] System.Web.UI.ScriptManager.OnInit(EventArgs e) +384613 System.Web.UI.Control.InitRecursive(Control namingContainer) +333 System.Web.UI.Control.InitRecursive(Control namingContainer) +210 System.Web.UI.Control.InitRecursive(Control namingContainer) +210 System.Web.UI.Control.InitRecursive(Control namingContainer) +210 System.Web.UI.Control.InitRecursive(Control namingContainer) +210 System.Web.UI.Control.InitRecursive(Control namingContainer) +210 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +378 What causes this? Thanks

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  • How to grant permissions to single SELECT/UPDATE statment (sql server) ?

    - by Albert
    I have a problem when trying to execute this update statement (below) using C# SqlCommand when I execute it locally it works fine, but when deployed to another machine I got a permission error The SELECT permission was denied on the object Order ... The UPDATE permission was denied on the object Order ... Update Statement "UPDATE Order SET Request = @request WHERE Id = @ID"; Is there any way to add GRANT SELECT and GRANT UPDATE to a single statement like the update above without using a stored procedure? or the SP is the way to go on this? Thanks in advance

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  • how do I find the number of xml children in AS3

    - by vasion
    so live docs says this for calling .lenght() on an XML object For XML objects, this method always returns the integer 1. The length() method of the XMLList class returns a value of 1 for an XMLList object that contains only one value. i called it on an xml that looked like this: <xml> <picture>1</picture> <picture>2</picture> </xml> and it reallt returned 1. how do i get the number of children in my xml?

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  • Get a queryset of objects through an intermediary model

    - by skyl
    I want get all of the Geom objects that are related to a certain content_object (see the function I'm trying to build at the bottom, get_geoms_for_obj() class Geom(models.Model): ... class GeomRelation(models.Model): ''' For tagging many objects to a Geom object and vice-versa''' geom = models.ForeignKey(Geom) content_type = models.ForeignKey(ContentType) object_id = models.PositiveIntegerField() content_object = generic.GenericForeignKey() def get_geoms_for_object(obj): ''' takes an object and gets the geoms that are related ''' ct = ContentType.objects.get_for_model(obj) id = obj.id grs = GeomRelation.objects.filter( content_type=ct, object_id=id ) # how with django orm magic can I build the queryset instead of list # like below to get all of the Geom objects for a given content_object geoms = [] for gr in grs: geoms.append(gr.geom) return set(geoms) # A set makes it so that I have no redundant entries but I want the # queryset ordering too .. need to make it a queryset for so many reasons...

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  • OOP App Architecture: Which layer does a lazy loader sit in?

    - by JW
    I am planning the implemention an Inheritance Mapper pattern for an application component http://martinfowler.com/eaaCatalog/inheritanceMappers.html One feature it needs to have is for a domain object to reference a large list of aggreageted items (10,000 other domain objects) So I need some kind of lazy loading collection to be passed out of the aggregate root domain object to other domain objects. To keep my (php) model scripts organised i am storing them in two folders: MyComponent\ controllers\ models\ domain\ <- domain objects, DDD repository, DDD factory daccess\ <- PoEAA data mappers, SQL queries etc views\ But now I am racking my brains wondering where my lazy loading collection sits. Any suggestions / justifications for putting it in one place over another another? DDD = Domain Driven Design Patterns, Eric Evans - book PoEAA = Patterns of Application Architecture Patterns, Martin Fowler - book

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  • Properties are making trouble

    - by DhavalR
    In my application I have added a Properties.cs file which contains properties that I am would use through out the application. I am getting NullReferenceException = Object reference not set to an instance of an object. Here is the code for Properties.cs public class Properties { private static string type1; public static string Type1 { get { return type1; } set { type1= value; } } } And when I access this property in one of my form I am getting error. e.g. if (Properties.Type1.Equals(string.Empty) || Properties.Type1.Equals(null)) { //// Do something }

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  • Is it possible to have a Shared/Static Dependency Property?

    - by Matt H.
    [using VB.NET, but I can easily read C# code in responses] I have a class called QuestionClipboard with ALL shared methods/properties. I previously had a QuesitonClipboard.doesClipboardHaveContent function that returned true/false if there was a Object on my 'clipboard'. I'd prefer to implement a Dependency Property so I can allow this true/false value to participate in data binding. The "GetValue(dp as DependencyProperty)" method requires an object instance, which would mean that my Property CAN'T be shared! Here is what the code would look like in my perfect world... Of course, the word "Shared" before the property declaration renders this code useless. Private Shared clipboardHasContentPropertyKey As DependencyPropertyKey = DependencyProperty.RegisterReadOnly("clipboardHasContent", GetType(Boolean), GetType(QuestionClipboard), _ New PropertyMetadata(False, Nothing, New CoerceValueCallback(AddressOf coerceClipboardHasContent))) Private Shared clipboardHasContentProperty As DependencyProperty = clipboardHasContentPropertyKey.DependencyProperty Public SHARED Property clipboardHasContent As Boolean Get Return GetValue(clipboardHasContentProperty) End Get Set(ByVal value As Boolean) SetValue(value) End Set End Property

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  • Why people do not like OOP? [closed]

    - by Gabriel Šcerbák
    I do not understand why people choose C++ over Smalltalk in past and why Java over Python or Ruby. What is it that ties people so much to the procedural programming and makes it so difficult to go "all the way" to object oriented programming? What makes OOP hard? Should not objects be an abstraction which is easier to grasp for people, i.e. a more natural one than procedures? Is education the problem (because people tend to learn procedural programming before object oriented)?

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  • How can I create a generic constructor? (ie. BaseClass.FromXml(<param>)

    - by SofaKng
    I'm not sure how to describe this but I'm trying to create a base class that contains a shared (factory) function called FromXml. I want this function to instantiate an object of the proper type and then fill it via an XmlDocument. For example, let's say I have something like this: Public Class XmlObject Public Shared Function FromXml(ByVal source as XmlDocument) As XmlObject // <need code to create SPECIFIC TYPE of object and return it End Function End Class Public Class CustomObject Inherits XmlObject End Class I'd like to be able to do something like this: Dim myObject As CustomObject = CustomObject.FromXml(source) Is this possible?

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  • WCF DataContract GetCustomDataToExport

    - by JeffN825
    I'm trying to get the default behavior for a client referencing my WCF WSDL to set IsReference to true on the imported DataContracts. It looks like I should be able to use an IDataContractSurrogate with GetCustomDataToExport to accomplish this...which specifcally means adding the following to the generated ComplexType in the xsd associated with the WSDL: <xs:attribute ref="ser:Id" /> <xs:attribute ref="ser:Ref" /> There is, of course no usable documentation I can find from MS about how to use this method. The MSDN page says it should return an object...but does not indicate at all what type of object this should be....how useless... Before I go reflector'ing for this, does anyone out there know how to use this method? Thanks.

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  • C++ game designing & polymorphism question

    - by Kotti
    Hi! I'm trying to implement some sort of 'just-for-me' game engine and the problem's plot goes the following way: Suppose I have some abstract interface for a renderable entity, e.g. IRenderable. And it's declared the following way: interface IRenderable { // (...) // Suppose that Backend is some abstract backend used // for rendering, and it's implementation is not important virtual void Render(Backend& backend) = 0; }; What I'm doing right now is something like declaring different classes like class Ball : public IRenderable { virtual void Render(Backend& backend) { // Rendering implementation, that is specific for // the Ball object // (...) } }; And then everything looks fine. I can easily do something like std::vector<IRenderable*> items, push some items like new Ball() in this vector and then make a call similiar to foreach (IRenderable* in items) { item->Render(backend); } Ok, I guess it is the 'polymorphic' way, but what if I want to have different types of objects in my game and an ability to manipulate their state, where every object can be manipulated via it's own interface? I could do something like struct GameState { Ball ball; Bonus bonus; // (...) }; and then easily change objects state via their own methods, like ball.Move(...) or bonus.Activate(...), where Move(...) is specific for only Ball and Activate(...) - for only Bonus instances. But in this case I lose the opportunity to write foreach IRenderable* simply because I store these balls and bonuses as instances of their derived, not base classes. And in this case the rendering procedure turns into a mess like ball.Render(backend); bonus.Render(backend); // (...) and it is bad because we actually lose our polymorphism this way (no actual need for making Render function virtual, etc. The other approach means invoking downcasting via dynamic_cast or something with typeid to determine the type of object you want to manipulate and this looks even worse to me and this also breaks this 'polymorphic' idea. So, my question is - is there some kind of (probably) alternative approach to what I want to do or can my current pattern be somehow modified so that I would actually store IRenderable* for my game objects (so that I can invoke virtual Render method on each of them) while preserving the ability to easily change the state of these objects? Maybe I'm doing something absolutely wrong from the beginning, if so, please point it out :) Thanks in advance!

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  • How to read from CSS files with jQuery

    - by Neurofluxation
    Ok, I have a HTML page with jQuery included. I have a CSS file with a good load of lines in, I would like to read all styles for a given element from the external CSS file... Not the inline styles... I have the following code (which looks like it should work...): var styleProperties= {}; var getCssProperties = ['width', 'margin', 'height']; for (c=0;i<=returnStyleProps.length;c++) { styleProperties[returnStyleProps[c]] = $('div#container').css(returnStyleProps[c]); alert(styleProperties); } alert(styleProperties); But this only seems to alert: "[Object Object]" Any ideas you clever people?

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  • Unset/Change Binding in WPF

    - by captcalamares
    How can I unset the binding applied to an object so that I can apply another binding to it from a different location? Suppose I have two data templates binded to the same object reference. Data Template #1 is the default template to be loaded. I try to bind a button command to a Function1 from my DataContext class: <Button Content="Button 1" CommandParameter="{Binding }" Command="{Binding DataContext.Function1, RelativeSource={RelativeSource AncestorType={x:Type Window}}}"/> This actually works and the function gets binded. However, when I try to load Data Template # 2 to the same object (while trying to bind another button command to a different function (Function2) from my DataContext class): <Button Content="Button 2" CommandParameter="{Binding }" Command="{Binding DataContext.Function2, RelativeSource={RelativeSource AncestorType={x:Type Window}}}" /> It doesn't work and the first binding is still the one executed. Is there a workaround to this? EDIT (for better problem context): I defined my templates in my Window.Resources: <Window.Resources> <DataTemplate DataType="{x:Type local:ViewModel1}"> <local:View1 /> </DataTemplate> <DataTemplate DataType="{x:Type local:ViewModel2}"> <local:View2 /> </DataTemplate> </Window.Resources> The View1.xaml and the View2.xaml contain the button definitions that I described above (I want them to command the control of my process flow). ViewModel1 and ViewModel2 are my ViewModels that implement the interface IPageViewModel which is the type of my variable CurrentPageViewModel. In my XAML, I binded ContentControl to the variable CurrentPageViewModel: <ContentControl Content="{Binding CurrentPageViewModel}" HorizontalAlignment="Center"/> In my .CS, I have a list defined as List<IPageViewModel> PageViewModels, which I use to contain the instances of my two View Models: PageViewModels.Add(new ViewModel1()); PageViewModels.Add(new ViewModel2()); // Set starting page CurrentPageViewModel = PageViewModels[0]; When I try to change my CurrentPageViewModel to the other view model, this is when I want the new binding to work. Unfortunately, it doesn't. Am I doing things the right way?

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