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  • Validates presence of each other in two associated models

    - by Sergey Alekseev
    I have the following two models: class Parent < ActiveRecord::Base has_one :child, dependent: :destroy validates :child, presence: true end class Child < ActiveRecord::Base belongs_to :parent validates :parent, presence: true end I want to create Parent object. If I do the following: Parent.create! or Factory(:parent) Exception raises: ActiveRecord::RecordInvalid: Validation failed: Child can't be blank But I can't create Child object without Parent object for the same reason - I need to create Parent object first in order to pass presence validation. As it appears I have some kind of infinite recursion here. How to solve it?

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  • rvalues and temporary objects in the FCD

    - by FredOverflow
    It took me quite some time to understand the difference between an rvalue and a temporary object. But now the final committee draft states on page 75: An rvalue [...] is an xvalue, a temporary object or subobject thereof, or a value that is not associated with an object. I can't believe my eyes. This must be an error, right?

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  • Javascript: 'this' changes when assigning a property?

    - by Pickels
    I know 'this' can be a problem when you don't understand Javascript well but this one got me a little puzzled. var ControlTypes = { TextBox: function () { console.log(this); this.Name = "TextBox"; console.log(this); } } ControlTypes.TextBox(); Firebug gives the following result: Object {} Object { Name="TextBox"} The first object is ControlTypes and the second one is Textbox. Could anybody explain the behavior behind this?

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  • Is It Possible To Cast A Range

    - by Brad Rhoads
    I'd like to do something like this: def results = Item.findAll("from Item c, Tag b, ItemTag a where c = a.item and b = a.tag and (b.tag like :q or c.uri like :q) " + ob,[q:q]) def items = (Item) results[0..1][0] but I get Cannot cast object '[Ljava.lang.Object;@1e224a5' with class '[Ljava.lang.Object;' to class 'org.maflt.ibidem.Item' I can get what I need with this, but it doesn't seem like it's the best solution: def items = [] as Set def cnt = results.size() for (i=0;i<cnt-1;i++) { items << results[i][0] } items = items as List

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  • Why Is the sender type null when dealing with events

    - by ChloeRadshaw
    From C# Via CLR: Note A lot of people wonder why the event pattern requires the sender parameter to always be of type Object After all, since the MailManager will be the only type raising an event with a NewMail EventArgs object, it makes more sense for the callback method to be prototyped like this: void MethodName(Mai l Manager sender, NewMail EventArgs e); The pattern requires the sender parameter to be of type Object mostly because of inheritance What if Mai lManager were used as a base class for SmtpMailManager? In this case, the callback method should have the sender parameter prototyped as SmtpMailManager instead of Mail Manager, but this can’t happen because SmtpMai lManager just inherited the NewMai l event So the code that was expecting SmtpMail Manager to raise the event must still have to cast the sender argument to SmtpMailManager In other words, the cast is still required, so the sender parameter might as well be typed as Obj ect The next reason for typing the sender parameter as Obj ect is just fexibility It allows the delegate to be used by multiple types that offer an event that passes a NewMail EventArgs object For example, a PopMai lManager class could use the delegate even if this class were not derived from Mail Manager I just simply cannot understand why the sender is an object - Why can it not be generified? so most of the time we do not need to do generic casts

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  • C# Casting system.__comobject to class type

    - by ijrufus
    I have an Excel Add-In that I'm currently trying to set up a unit test framework for. For the unit tests I've followed this guide: http://blogs.msdn.com/b/varsha/archive/2010/08/17/writing-automated-test-cases-for-vsto-application.aspx It seems to work fine, until I want to return a class object from my interface. Specifying the class object as the return type throws a "return argument has an invalid type" exception when calling the method. Changing the return type from the class to an object allows me to call the method and get the object, but now I'm unable to cast it as the class and use it as intended, getting this exception message when I try: > Unable to cast COM object of type 'System.__ComObject' to class type > 'anaplan.Utility.XYCoordinates'. Instances of types that represent COM > components cannot be cast to types that do not represent COM > components; however they can be cast to interfaces as long as the > underlying COM component supports QueryInterface calls for the IID of > the interface. I've retrieved the Type name using VisualBasic.Information.TypeName and it's showing it as the class I expect. Is there any way to get the comobject cast back to the class? Or another way to access the properties it has? Or am I just being a bit stupid here?

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  • Is it any loose coupling mechanism in Objective-C + Cocoa like C# delegates or C++Qt signals+slots?

    - by Eye of Hell
    Hello. For a large programs, the standard way to chalenge a complexity is to divide a program code into small objects. Most of the actual programming languages offer this functionality via classes, so is Objective-C. But after source code is separated into small object, the second challenge is to somehow connect them with each over. Standard approaches, supported by most languages are compositon (one object is a member field of another), inheritance, templates (generics) and callbacks. More cryptic techniques include method-level delagates (C#) and signals+slots (C++Qt). I like the delegates / signals idea, since while connecting two objects i can connect individual methods with each over, without objects knowing anything of each over. For C#, it will look like this: var object1 = new CObject1(); var object2 = new CObject2(); object1.SomethingHappened += object2.HandleSomething; In this code, is object1 calls it's SomethingHappened delegate (like a normal method call) the HandleSomething method of object2 will be called. For C++Qt, it will look like this: var object1 = new CObject1(); var object2 = new CObject2(); connect( object1, SIGNAL(SomethingHappened()), object2, SLOT(HandleSomething()) ); The result will be exactly the same. This technique has some advantages and disadvantages, but generally i like it more than interfaces since if program code base grows i can change connections and add new ones without creating tons of interfaces. After examination of Objective-C i havn't found any way to use this technique i like :(. It seems that Objective-C supports message passing perfectly well, but it requres for object1 to have a pointer to object2 in order to pass it a message. If some object needs to be connected to lots of other objects, in Objective-C i will be forced to give him pointers to each of the objects it must be connected. So, the question :). Is it any approach in Objective-C programming that will closely resemble delegate / signal+slot types of connection, not a 'give first object an entire pointer to second object so it can pass a message to it'. Method-level connections are a bit more preferable to me than object-level connection ^_^.

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  • Grails populate params with XML from POST request

    - by othman
    I have a RestFull grails api that i expose through grails Controller. I need to automatically bind the xml data sent in a POST request. I don't think using groovy bindData(object,params) works as the params reference seems not having the xml elements. i use the parseRequest=true in the UrlMappings but yet the params Object does'nt have the xml elements. am i missing some other config so that my params object get automatically populated with the xml body elements?

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  • Get Youtube Video ID from html code with PHP

    - by asumaran
    I want to get all only youtube video ID from html code look the (or multiple) object/embed code for youtube video // html from database <p>loremm ipsum dolor sit amet enot <a href="link" attribute=""blah blah blah">anchor link</a> </p> <object width="425" height="344"> <param name="movie" value="http://www.youtube.com/v/Ou5eVl5eqtg&hl=es_ES&fs=1&"></param> <param name="allowFullScreen" value="true"></param> <param name="allowscriptaccess" value="always"></param> <embed src="http://www.youtube.com/v/Ou5eVl5eqtg&hl=es_ES&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"> </embed> </object> <image src="path/to/image.ext" > <p>lorem ipsum dolor sit amet... blah</p> <p>lorem ipsum dolor sit amet... blah</p> <object width="425" height="344"> <param name="movie" value="http://www.youtube.com/v/Ou5eVl5eqtg&hl=es_ES&fs=1&"></param> <param name="allowFullScreen" value="true"></param> <param name="allowscriptaccess" value="always"></param> <embed src="http://www.youtube.com/v/Ou5eVl5eqtg&hl=es_ES&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"> </embed> </object> <p>blah</p> blah<br/> blah<br/> blah<br/>

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  • Force deletion of slot in boost::signals2

    - by villintehaspam
    Hi! I have found that boost::signals2 uses sort of a lazy deletion of connected slots, which makes it difficult to use connections as something that manages lifetimes of objects. I am looking for a way to force slots to be deleted directly when disconnected. Any ideas on how to work around the problem by designing my code differently are also appreciated! This is my scenario: I have a Command class responsible for doing something that takes time asynchronously, looking something like this (simplified): class ActualWorker { public: boost::signals2<void ()> OnWorkComplete; }; class Command : boost::enable_shared_from_this<Command> { public: ... void Execute() { m_WorkerConnection = m_MyWorker.OnWorkDone.connect(boost::bind(&Command::Handle_OnWorkComplete, shared_from_this()); // launch asynchronous work here and return } boost::signals2<void ()> OnComplete; private: void Handle_OnWorkComplete() { // get a shared_ptr to ourselves to make sure that we live through // this function but don't keep ourselves alive if an exception occurs. shared_ptr<Command> me = shared_from_this(); // Disconnect from the signal, ideally deleting the slot object m_WorkerConnection.disconnect(); OnComplete(); // the shared_ptr now goes out of scope, ideally deleting this } ActualWorker m_MyWorker; boost::signals2::connection m_WorkerConnection; }; The class is invoked about like this: ... boost::shared_ptr<Command> cmd(new Command); cmd->OnComplete.connect( foo ); cmd->Execute(); // now go do something else, forget all about the cmd variable etcetera. the Command class keeps itself alive by getting a shared_ptr to itself which is bound to the ActualWorker signal using boost::bind. When the worker completes, the handler in Command is invoked. Now, since I would like the Command object to be destroyed, I disconnect from the signal as can be seen in the code above. The problem is that the actual slot object is not deleted when disconnected, it is only marked as invalid and then deleted at a later time. This in turn appears to depend on the signal to fire again, which it doesn't do in my case, leading to the slot never expiring. The boost::bind object thus never goes out of scope, holding a shared_ptr to my object that will never get deleted. I can work around this by binding using the this pointer instead of a shared_ptr and then keeping my object alive using a member shared_ptr which I then release in the handler function, but it kind of makes the design feel a bit overcomplicated. Is there a way to force signals2 to delete the slot when disconnecting? Or is there something else I could do to simplify the design? Any comments are appreciated!

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  • How to reflect over T to build an expression tree for a query?

    - by Alex
    Hi all, I'm trying to build a generic class to work with entities from EF. This class talks to repositories, but it's this class that creates the expressions sent to the repositories. Anyway, I'm just trying to implement one virtual method that will act as a base for common querying. Specifically, it will accept a an int and it only needs to perform a query over the primary key of the entity in question. I've been screwing around with it and I've built a reflection which may or may not work. I say that because I get a NotSupportedException with a message of LINQ to Entities does not recognize the method 'System.Object GetValue(System.Object, System.Object[])' method, and this method cannot be translated into a store expression. So then I tried another approach and it produced the same exception but with the error of The LINQ expression node type 'ArrayIndex' is not supported in LINQ to Entities. I know it's because EF will not parse the expression the way L2S will. Anyway, I'm hopping someone with a bit more experience can point me into the right direction on this. I'm posting the entire class with both attempts I've made. public class Provider<T> where T : class { protected readonly Repository<T> Repository = null; private readonly string TEntityName = typeof(T).Name; [Inject] public Provider( Repository<T> Repository) { this.Repository = Repository; } public virtual void Add( T TEntity) { this.Repository.Insert(TEntity); } public virtual T Get( int PrimaryKey) { // The LINQ expression node type 'ArrayIndex' is not supported in // LINQ to Entities. return this.Repository.Select( t => (((int)(t as EntityObject).EntityKey.EntityKeyValues[0].Value) == PrimaryKey)).Single(); // LINQ to Entities does not recognize the method // 'System.Object GetValue(System.Object, System.Object[])' method, // and this method cannot be translated into a store expression. return this.Repository.Select( t => (((int)t.GetType().GetProperties().Single( p => (p.Name == (this.TEntityName + "Id"))).GetValue(t, null)) == PrimaryKey)).Single(); } public virtual IList<T> GetAll() { return this.Repository.Select().ToList(); } protected virtual void Save() { this.Repository.Update(); } }

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  • How can I center a box of unknown width in CSS?

    - by NXTBoy
    I have this html: <div class="object-box"> <img ... /> <span class="caption">This is the caption</span> </div> Which is accompanied with this CSS: .object-box .caption, .object-box img { display: block; } .object-box { border: 1px solid; } I would like the surrounding div to shrink-wrap to its contents. I can achieve this by using float: ... or display: inline-block. However, I'd also like it to be centered on the page, using margin: auto. The two approaches don't seem to be compatible. Is it possible to create such a shrink-wrapped, centered container, without adding a wrapper element?

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  • StreamSocket to Stream in windows phone 8

    - by Abouzar Nouri
    I am trying to use Bluetooth in WP8 to send an image from my app on a device and show it in my app on another device. The receiver has a StreamSocket object to read the data from it like the code below await _dataReader.LoadAsync(4); uint messageLen = (uint)_dataReader.ReadInt32(); await _dataReader.LoadAsync(messageLen); string imageData _dataReader.ReadString(messageLen); Then I have to save all the received data (image) on the device and then create a Stream object from the stored data to give it to the BitmapSource.SetSource(Stream) function to be able to show this image on my app. var image = new BitmapImage(); image.SetSource(stream); All I want to do is not to skip this double work and directly convert the StreamSocket object (from Bluetooth connection) to a Stream object and make the BitmapSource image. Is there any way to do this?

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  • When to retain a "delegate"

    - by Jose
    I know that in Objective-C you should never retain your delegates because it may cause a retain-cycle, however, how do you know the difference between a delegate and a non-delegate object ? Can't it be said that just sending a message to any object is delegating work to that object ?

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  • How to create a dynamic number of possibly children objects using partial views?

    - by NullReference
    I have a parent object that contains a property that is a list of children objects. I'd like to have it so that when the form loads to create the parent object a partial view is used to create the list of child objects. The problem is I have to idea how to have the list of children object populated. I can do one object ok, but a dynamic list of possible children is difficult. Any ideas? @Html.RenderPartial("_CreateChild", Model.Children); public class Parent { private List<Child> _list; public Guid Id { get; set; } public List<Child> Children { get { return _list; } set { _list = value; } } public Parent() { _list = new List<Child>(); } }

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  • How to draw mutiple rectangles using c#

    - by Nivas
    I have drawn and saved the Rectangle on the image i loaded in the picture box. How i like to draw multiple rectangles for that i tried array in the rectangle but it gives error ("Object reference not set to an instance of an object." (Null reference Exception was unhandled). enter code here private void pictureBox1_MouseDown(object sender, MouseEventArgs e) { if (mybitmap == null) { mybitmap = new Bitmap(sz.Width, sz.Height); } rect = new Rectangle(e.X, e.Y, 0, 0); this.Invalidate(); } private void pictureBox1_MouseMove(object sender, MouseEventArgs e) { if (stayToolStripMenuItem.Checked == true) { switch (e.Button) { case MouseButtons.Left: { rect = new Rectangle(rect.Left, rect.Top, e.X - rect.Left, e.Y - rect.Top); pictureBox1.Invalidate(); break; } } } } private void pictureBox1_Paint(object sender, PaintEventArgs e) { if (stayToolStripMenuItem.Checked == true) { button1.Visible = true; button2.Visible = true; if (mybitmap == null) { return; } using (g = Graphics.FromImage(mybitmap)) { using (Pen pen = new Pen(Color.Red, 2)) { //g.Clear(Color.Transparent); e.Graphics.DrawRectangle(pen, rect); label1.Top = rect.Top; label1.Left = rect.Left; label1.Width = rect.Width; label1.Height = rect.Height; if (label1.TextAlign == ContentAlignment.TopLeft) { e.Graphics.DrawString(label1.Text, label1.Font, new SolidBrush(label1.ForeColor), rect); g.DrawString(label1.Text, label1.Font, new SolidBrush(label1.ForeColor), rect); g.DrawRectangle(pen, rect); } } } } } How can i do this.....

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  • Unknown margin being added to a footer in IE6 + 7

    - by Qwibble
    So yeah, like I said, I've spent a few hours trying to fix this bug in the footer that add's an extra 20-30px on to the bottom of the page in IE6 and 7. I've currently set all bottom margins to 0 so as to find what's causing it, I then scoured ie developer tools but came up empty. Here's the homepage design hosted on my web design playground - Link Can anyone see the remedy?

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  • How does one refer to the game1 class's variables in XNA

    - by user1149068
    I try to refer to an array in the Game1 class by creating an object of the Game1 class with its definition Game1 gameObject; , its declaration gameObject = new Game1(); in the constructor, and its usage gameObject.tileArray[xInt, yInt].treed = true;. The game1 class itself remains unchanged in its class code other than some methods and variables. When I try to use this code in the TreeRegion class it gives me "Object reference not set to an instance of an object," leading me to believe that the game1 class is null somehow. How might one change the class or object in order to refer to game1's variables? Mind you I am self-taught and still rather new to C#. The class that refers to game1: http://pastebin.com/0chEcKfq Game1 itself http://pastebin.com/zLDVzCca

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  • C# == operator in Immediate window behaves differently than at run-time

    - by Damiano
    Try the following in the Immediate window: object a1 = "a"; object a2 = "a"; a1==a2 // outputs false and you'll see that a1 == a2 outputs false. However, at runtime in either a window app or console, you'll get true: object t1 = "a"; object t2 = "a"; MessageBox.Show((t1 == t2).ToString()); // outputs true The runtime behavior is consistent with the definition for the == operator and strings. Does anybody know if this a bug in the Immediate window?

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  • Translate from c# to c++

    - by Xaver
    Help to translate from c# code to c++ code. Type tp = Type.GetTypeFromProgID("Shell.Application"); object o = Activator.CreateInstance(tp); Object[] arg = new Object[1]; arg[0] = "C:\\!!"; object b = o.GetType().InvokeMember(@"NameSpace", BindingFlags.Public | BindingFlags.InvokeMethod, null, o, arg); arg[0] = "ftp://anonymous:[email protected]/bussys/1394"; b.GetType().InvokeMember(@"CopyHere", BindingFlags.Public | BindingFlags.InvokeMethod, null, b, arg);

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  • siverlight and windows workflow foundation

    - by wissem
    private void btnUpdate_Click(object sender, RoutedEventArgs e) { xxxxxxx.Workflow1_WebServiceSoapClient zer = new xxxxx.Workflow1_WebServiceSoapClient(); zer.demanderSubmitReportCompleted += new EventHandler<xxxxxxxxxxxxxxx.demanderSubmitReportCompletedEventArgs>(service2); zer.demanderSubmitReportAsync("zzz", 20000); } public void service2(object sender, xxxxx.demanderSubmitReportCompletedEventArgs e) { string a = e.Result; } I'm trying to call a windows workflow foundation published as a web service from a Silverlight project. When I call it from a console application it works fine because I can add a web reference then I just make an instance of that webservice then I invoke the method I want. The problem is in the silverlight project cause i can just add a service reference so I find myself working with soap stuff that doesn't work at all, and here is the code error: here is the code error:i change it a litle bit in english Error in exécution Microsoft JScript: Unhandled Error in Silverlight Application exception happened in the operation, résult not valide. Consult InnerException for more information. in System.ComponentModel.AsyncCompletedEventArgs.RaiseExceptionIfNecessary() in AEDSilverlightIntegrated.ServiceReference2.demanderSubmitReportCompletedEventArgs.get_Result() in AEDSilverlightIntegrated.SilverEntryAedHeaderNew.mmm_demanderSubmitReportCompleted(Object sender, demanderSubmitReportCompletedEventArgs e) in AEDSilverlightIntegrated.ServiceReference2.Workflow1_WebServiceSoapClient.OndemanderSubmitReportCompleted(Object state)

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  • Correct term for PSD to HTML to CMS

    - by John Magnolia
    Hi, I have heard a lot of different terms to describe the process of turning a website design into a editable CMS. Currently I take the design and "slice" this up into HTML and CSS then I "plug" this into a CMS. I would class this as frontend development depending on the level of customisation required for the CMS. The reason I ask is I am currently writing up my CV and have become stuck on the correct term for this. Kind Regards

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