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  • F# and statically checked union cases

    - by Johan Jonasson
    Soon me and my brother-in-arms Joel will release version 0.9 of Wing Beats. It's an internal DSL written in F#. With it you can generate XHTML. One of the sources of inspiration have been the XHTML.M module of the Ocsigen framework. I'm not used to the OCaml syntax, but I do understand XHTML.M somehow statically check if attributes and children of an element are of valid types. We have not been able to statically check the same thing in F#, and now I wonder if someone have any idea of how to do it? My first naive approach was to represent each element type in XHTML as a union case. But unfortunately you cannot statically restrict which cases are valid as parameter values, as in XHTML.M. Then I tried to use interfaces (each element type implements an interface for each valid parent) and type constraints, but I didn't manage to make it work without the use of explicit casting in a way that made the solution cumbersome to use. And it didn't feel like an elegant solution anyway. Today I've been looking at Code Contracts, but it seems to be incompatible with F# Interactive. When I hit alt + enter it freezes. Just to make my question clearer. Here is a super simple artificial example of the same problem: type Letter = | Vowel of string | Consonant of string let writeVowel = function | Vowel str -> sprintf "%s is a vowel" str I want writeVowel to only accept Vowels statically, and not as above, check it at runtime. How can we accomplish this? Does anyone have any idea? There must be a clever way of doing it. If not with union cases, maybe with interfaces? I've struggled with this, but am trapped in the box and can't think outside of it.

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  • I am looking for an actual functional web browser control for .NET, maybe a C++ library

    - by Joshua
    I am trying to emulate a web browser in order to execute JavaScript code and then parse the DOM. The System.Windows.Forms.WebBrowser object does not give me the functionality I need. It let's me set the headers, but you cannot set the proxy or clear cookies. Well you can, but it is not ideal and messes with IE's settings. I've been extending the WebBrowser control pinvoking native windows functions so far, but it is really one hack on top of another. I can mess with the proxy and also clear cookies and such, but this control has its issues as I mentioned. I found something called WebKit .NET (http://webkitdotnet.sourceforge.net/), but I don't see support for setting proxies or cookie manipulation. Can someone recommend a c++/.NET/whatever library to do this: Basically tell me what I need to do to get an interface to similar this in .NET: // this should probably pause the current thread for the max timeout, // throw an exception on failure or return null w/e, VAGUELY similar to this string WebBrowserEmu::FetchBrowserParsedHtml(Uri url, WebProxy p, int timeoutSeconds, byte[] headers, byte[] postdata); void WebBrowserEmu::ClearCookies(); I am not responsible for my actions.

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  • wrapping user controls in a transaction

    - by Hans Gruber
    I'm working on heavily dynamic and configurable CMS system. Therefore, many pages are composed of a dynamically loaded set of user controls. To enable loose coupling between containers (pages) and children (user controls), all user controls are responsible for their own persistence. Each User Control is wired up to its data/service layer dependencies via IoC. They also implement an IPersistable interface, which allows the container .aspx page to issue a Save command to its children without knowledge of the number or exact nature of these user controls. Note: what follows is only pseudo-code: public class MyUserControl : IPersistable, IValidatable { public void Save() { throw new NotImplementedException(); } public bool IsValid() { throw new NotImplementedException(); } } public partial class MyPage { public void btnSave_Click(object sender, EventArgs e) { foreach (IValidatable control in Controls) { if (!control.IsValid) { throw new Exception("error"); } } foreach (IPersistable control in Controls) { if (!control.Save) { throw new Exception("error"); } } } } I'm thinking of using declarative transactions from the System.EnterpriseService namespace to wrap the btnSave_Click in a transaction in case of an exception, but I'm not sure how this might be achieved or any pitfalls to such an approach.

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  • ArrayList.Sort should be a stable sort with an IComparer but is not?

    - by Kaleb Pederson
    A stable sort is a sort that maintains the relative ordering of elements with the same value. The docs on ArrayList.Sort say that when an IComparer is provided the sort is stable: If comparer is set to null, this method performs a comparison sort (also called an unstable sort); that is, if two elements are equal, their order might not be preserved. In contrast, a stable sort preserves the order of elements that are equal. To perform a stable sort, you must implement a custom IComparer interface. Unless I'm missing something, the following testcase shows that ArrayList.Sort is not using a stable sort: internal class DisplayOrdered { public int ID { get; set; } public int DisplayOrder { get; set; } public override string ToString() { return string.Format("ID: {0}, DisplayOrder: {1}", ID, DisplayOrder); } } internal class DisplayOrderedComparer : IComparer { public int Compare(object x, object y) { return ((DisplayOrdered)x).DisplayOrder - ((DisplayOrdered)y).DisplayOrder; } } [TestFixture] public class ArrayListStableSortTest { [Test] public void TestWeblinkCallArrayListIsSortedUsingStableSort() { var call1 = new DisplayOrdered {ID = 1, DisplayOrder = 0}; var call2 = new DisplayOrdered {ID = 2, DisplayOrder = 0}; var call3 = new DisplayOrdered {ID = 3, DisplayOrder = 2}; var list = new ArrayList {call1, call2, call3}; list.Sort(new DisplayOrderedComparer()); // expected order (by ID): 1, 2, 3 (because the DisplayOrder // is equal for ID's 1 and 2, their ordering should be // maintained for a stable sort.) Assert.AreEqual(call1, list[0]); // Actual: ID=2 ** FAILS Assert.AreEqual(call2, list[1]); // Actual: ID=1 Assert.AreEqual(call3, list[2]); // Actual: ID=3 } } Am I missing something? If not, would this be a documentation bug or a library bug? Apparently using an OrderBy in Linq gives a stable sort.

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  • Why isn't my UITableView appearing in the correct scroll position?

    - by zbrimhall
    I have a split view-based app that presents a master-detail interface, and uses a popover to present the master list when in portrait mode. The popover presents a sectioned table view that ultimately gets populated by a subclass of NSFetchedResultsController. I can tap the tool bar button to present the master list, scroll to whatever row, and tap the row to dismiss the popover. My problem is that if the table is scrolled past the top of the second section, when I dismiss the popover and then later tap the toolbar button to re-present it, the table's scroll position is always set such that the first row of the second section is at the top of the list. If I haven't scrolled past the top of the second section, it correctly remembers its scroll position when the table is presented again. Similarly, in landscape mode, if I scroll the table past the top of the third section and then rotate to portrait, when I come back to landscape the scroll position is always set such that the first row of the third section is at the top of the list. I tried calling -scrollToNearestSelectedRowAtScrollPosition:animated in both the master view controller's -viewWillAppear, as well as in the split view delegate's splitViewController:popoverController:willPresentViewController:, to no effect. Anybody have a clue what I might be doing wrong?

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  • Excel 2010 64 bit can't create .net object

    - by aboes81
    I have a simple class library that I use in Excel. Here is a simplification of my class... using System; using System.Runtime.InteropServices; namespace SimpleLibrary { [ComVisible(true)] public interface ISixGenerator { int Six(); } public class SixGenerator : ISixGenerator { public int Six() { return 6; } } } In Excel 2007 I would create a macro enabled workbook and add a module with the following code: Public Function GetSix() Dim lib As SimpleLibrary.SixGenerator lib = New SimpleLibrary.SixGenerator Six = lib.Six End Function Then in Excel I could call the function GetSix() and it would return six. This no longer works in Excel 2010 64bit. I get a Run-time error '429': ActiveX component can't create object. I tried changing the platform target to x64 instead of Any CPU but then my code wouldn't compile unless I unchecked the Register for COM interop option, doing so makes it so my macro enable workbook cannot see SimpleLibrary.dll as it is no longer regsitered. Any ideas how I can use my library with Excel 2010 64 bit?

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  • Why is my UITableView not being set?

    - by Jamie L
    I checked using the debbuger in the viewDidLoad method and tracerTableView is 0x0 which i assume means it is nil. I don't understand. I should go ahaed say yes I have already checked my nib file and yes all the connections are correct. Here is the header file and the begging of the .m. ///////////// .h file //////////// @interface TrackerListController : UITableViewController { // The mutable (modifiable) dictionary days holds all the data for the days tab NSMutableArray *trackerList; UITableView *tracerTableView; } @property (nonatomic, retain) NSMutableArray *trackerList; @property (nonatomic, retain) IBOutlet UITableView. *tracerTableView; //The addPackage: method is invoked when the user taps the addbutton created at runtime. -(void) addPackage : (id) sender; @end /////////////////////////////////////////////////////////////////////////////////////////////////// ////////////////////////////////////// .m file ////////////////////////////////////// @implementation TrackerListController @synthesize trackerList, tracerTableView; (void)viewDidLoad { [super viewDidLoad]; self.title = @"Package Tracker"; self.navigationItem.leftBarButtonItem = self.editButtonItem; UIBarButtonItem *addButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(addPackage:)]; // Set up the Add custom button on the right of the navigation bar self.navigationItem.rightBarButtonItem = addButton; [addButton release]; // Release the addButton from memory since it is no longer needed }

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  • Exception while hosting a WCF Service in a DependencyInjection Module ?

    - by Maciek
    Hello, I've written a small just-for-fun console project using Ninject, I'm pasting some of the code below just so that you get the idea : Program.cs using System; using Ninject; using Ninjectionn.Modules; // My namespace for my modules namespace Ninjections { class Program { static void Main(string[] args) { IKernel kernel = new StandardKernel(); kernel.Load<ServicesHostModule>(); Console.ReadKey(); } } } ServicesHostModule.cs using System; using System.ServiceModel; using Ninject; using Ninject.Modules; namespace Ninjections.Modules { public class ServicesHostModule : INinjectModule { #region INinjectModule Members public string Name { get { return "ServicesHost"; }} public void OnLoad(IKernel kernel) { if(m_host != null) m_host.Close(); else m_host = new ServiceHost(typeof(WCFTestService)); m_host.Open(); // (!) EXCEPTION HERE } public void OnUnLoad(IKernel kernel) { m_host.Close(); } #endregion } } ITestWCFService.cs using System.ServiceModel; namespace Ninjections.Modules { [ServiceContract] public interface ITestWCFService { [OperationContract] string GetString1(); [OperationContract] string GetString2(); } } An auto-generated App.config is in the ServicesHostModule project. I've "added" an existing item (the app config) as link in the main project. Q: at the m_host.Open(); line, an InvalidOperationException occurs. The message says : "Service "Ninjections.Modules.TestWCFService" has zero application endopints. What's wrong?

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  • Unity Framework constructor parameters in MVC

    - by ubersteve
    I have an ASP.NET MVC3 site that I want to be able to use different types of email service, depending on how busy the site is. Consider the following: public interface IEmailService { void SendEmail(MailMessage mailMessage); } public class LocalEmailService : IEmailService { public LocalEmailService() { // no setup required } public void SendEmail(MailMessage mailMessage) { // send email via local smtp server, write it to a text file, whatever } } public class BetterEmailService : IEmailService { public BetterEmailService (string smtpServer, string portNumber, string username, string password) { // initialize the object with the parameters } public void SendEmail(MailMessage mailMessage) { //actually send the email } } Whilst the site is in development, all of my controllers will send emails via the LocalEmailService; when the site is in production, they will use the BetterEmailService. My question is twofold: 1) How exactly do I pass the BetterEmailService constructor parameters? Is it something like this (from ~/Bootstrapper.cs): private static IUnityContainer BuildUnityContainer() { var container = new UnityContainer(); container.RegisterType<IEmailService, BetterEmailService>("server name", "port", "username", "password"); return container; } 2) Is there a better way of doing that - i.e. putting those keys in the web.config or another configuration file so that the site would not need to be recompiled to switch which email service it was using? Many thanks!

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  • Using StructureMap to create classes by a name?

    - by Bevan
    How can I use StructureMap to resolve to an appropriate implementation of an interface based on a name stored in an attribute? In my project, I have many different kinds of widgets, each descending from IWidget, and each decorated with an attribute specifying the kind of associated element. To illustrate: [Configuration("header")] public class HeaderWidget : IWidget { } [Configuration("linegraph")] public class LineGraphWidget : IWidget { } When processing my (XML) configuration file, I want to obtain an instance of the appropriate concrete class based on the name of the element I'm processing. public IWidget CreateWidget(XElement definition) { var kind = definition.Name.LocalName; var widget = // What goes here? widget.Configure(definition); return widget; } Each definition should result in a different widget being created - I don't need or want the instances to be shared. In the past I've written plenty of code to do this kind of thing manually, including writing a custom "roll-your-own" IoC container for one project. However, one of my goals with this project is to become proficient with StructureMap instead of reinventing the wheel. I think I've already managed to set up automatic scanning of assemblies so that StructureMap knows about all my IWidget implementations: public class WidgetRegistration : Registry { public WidgetRegistration() { Scan( scanner => { scanner.AssembliesFromApplicationBaseDirectory(); scanner.AddAllTypesOf<IWidget>(); }); } } However, this isn't registering the names of my widgets with StructureMap. What do I need to add to make my scenario work? (While I am trying to use StructureMap in this project, an answer showing me how to solve this problem with a different DI/IoC tool would still be valuable.)

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  • Can I add a portrait layout on top of a landscape Camera SurfaceView?

    - by Uwe Krass
    My application should hold a camera preview surface. The camera is fixed to landscape view via AndroidMainfest.xml <application android:icon="@drawable/icon" android:label="Camera"> <uses-library android:name="com.google.android.maps" /> <uses-feature android:name="android.hardware.camera" /> <uses-feature android:name="android.hardware.camera.autofocus" /> <activity android:name=".CameraPreview" android:label="Camera" android:screenOrientation="landscape"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> If there is another way to get the camera preview itself to behave correctly, please let me know. Now I need to have an overlay that holds a bunch of buttons. Due to usability, the user interface should be set to portrait view (or even better orientation aware). Is there a way to have a transparent layout (for buttons and other GUI elements) in portrait orientation? I tried to write a special rotated layout by extending a RelativeLayout, but the onDraw method isn't called at anytime. public class RotatedOverlay extends RelativeLayout { private static final String TAG = "RotatedOverlay"; public RotatedOverlay(Context context, AttributeSet attrs ) { super(context, attrs); } @Override protected void onDraw(Canvas canvas) { canvas.rotate(90); super.onDraw(canvas); } I am quite new to the Android plattform programming. Of course I dont know much about the programming tricks and workarounds yet. I did a lot of research over the last two weeks (even studied the native Camera implementation), but couldnt find a good solution so far. Maybe it works with two seperate Activities, but I dont think, that this can the right solution.

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  • Looking for a web based, embeddable file manager

    - by Kristi H.
    I'm looking for a web based, embeddable file manager. I haven't found anything suitable through Google or the Stack Overflow archives. Does anyone know of a file manager that meets the following criteria? The file manager must… …be embeddable (e.g. Flash or a Java applet) …run from my server (no storing uploads in a remote location) …be licensed for business use (fees are okay) …let me disable uploads. Users shouldn't be able to upload files, only download them …allow me to tag files and/or place them in folders …let me disable authentication or handle it from the backend. My app already has a login system and I don't want to make users log in twice …allow users to select and download multiple files …have an attractive interface The file manager should… …have an external config file …display thumbnail previews for files …be skinnable …be actively developed or at least actively maintained Thanks for your help. I need a sophisticated file manager and I'd like to avoid writing it from scratch.

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  • ASMX schema varies when using WCF Service

    - by Lijo
    Hi, I have a client (created using ASMX "Add Web Reference"). The service is WCF. The signature of the methods varies for the client and the Service. I get some unwanted parameteres to the method. Note: I have used IsRequired = true for DataMember. Service: [OperationContract] int GetInt(); Client: proxy.GetInt(out requiredResult, out resultBool); Could you please help me to make the schame non-varying in both WCF clinet and non-WCF cliet? Do we have any best practices for that? using System.ServiceModel; using System.Runtime.Serialization; namespace SimpleLibraryService { [ServiceContract(Namespace = "http://Lijo.Samples")] public interface IElementaryService { [OperationContract] int GetInt(); [OperationContract] int SecondTestInt(); } public class NameDecorator : IElementaryService { [DataMember(IsRequired=true)] int resultIntVal = 1; int firstVal = 1; public int GetInt() { return firstVal; } public int SecondTestInt() { return resultIntVal; } } } Binding = "basicHttpBinding" using NonWCFClient.WebServiceTEST; namespace NonWCFClient { class Program { static void Main(string[] args) { NonWCFClient.WebServiceTEST.NameDecorator proxy = new NameDecorator(); int requiredResult =0; bool resultBool = false; proxy.GetInt(out requiredResult, out resultBool); Console.WriteLine("GetInt___"+requiredResult.ToString() +"__" + resultBool.ToString()); int secondResult =0; bool secondBool = false; proxy.SecondTestInt(out secondResult, out secondBool); Console.WriteLine("SecondTestInt___" + secondResult.ToString() + "__" + secondBool.ToString()); Console.ReadLine(); } } } Please help.. Thanks Lijo

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  • Why doesn't C# do "simple" type inference on generics?

    - by Ken Birman
    Just curious: sure, we all know that the general case of type inference for generics is undecidable. And so C# won't do any kind of subtyping at all: if Foo<T> is a generic, Foo<int> isn't a subtype of Foo<T>, or Foo<Object> or of anything else you might cook up. And sure, we all hack around this with ugly interface or abstract class definitions. But... if you can't beat the general problem, why not just limit the solution to cases that are easy. For example, in my list above, it is OBVIOUS that Foo<int> is a subtype of Foo<T> and it would be trivial to check. Same for checking against Foo<Object>. So is there some other deep horror that would creep forth from the abyss if they were to just say, aw shucks, we'll do what we can? Or is this just some sort of religious purity on the part of the language guys at Microsoft?

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  • IBOutlet instances are (null) after loading from NIB

    - by Zach
    I am working on an iPhone app and am getting (null) references to IBOutlet fields in my controller. I have a UIViewController subclass that is set as the File's Owner in my XIB. I have a set of UI elements that are wired into the controller. After loading from NIB and attempting to set properties on those UI elements, I find that they are (null). To clarify, some code: ExpandSearchPageController.h: @interface ExpandSearchPageController : UIViewController { IBOutlet UITextView * completeMessageView; } -(void)checkTextField; @property (nonatomic, retain) IBOutlet UITextView * completeMessageView; ExpandSearchPageController.m: @implementation ExpandSearchPageController @synthesize completeMessageView; -(void)checkTextField { NSLog(@"text field: %@",completeMessageView); } ExpandSearchPageController is set as the File's Owner for ExpandSearchPage.xib. ExpandSearchPage.xib's UITextView is wired to the completeMessageView. When I call ExpandSearchPageController * searchExpanderPage = [[ExpandSearchPageController alloc] initWithNibName:@"ExpandSearchPage" bundle:[NSBundle mainBundle]]; [searchExpanderPage checkTextField]; the result is "text field: (null)" Sorry if this is a total newb question, but I guess I'm still a newb at iPhone programming! Thanks in advance!

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  • With a browser, how do I know which decimal separator does the client use?

    - by Quassnoi
    I'm developing a web application. I need to display some decimal data correctly so that it can be copied and pasted into a certain GUI application that is not under my control. The GUI application is locale sensitive and it accepts only the correct decimal separator which is set in the system. I can guess the decimal separator from Accept-Language and the guess will be correct in 95% cases, but sometimes it fails. Is there any way to do it on server side (preferably, so that I can collect statistics), or on client side? Update: The whole point of the task is doing it automatically. In fact, this webapp is a kind of online interface to a legacy GUI which helps to fill the forms correctly. The kind of users that use it mostly have no idea on what a decimal separator is. The Accept-Language solution is implemented and works, but I'd like to improve it. Update2: I need to retrive a very specific setting: decimal separator set in Control Panel / Regional and Language Options / Regional Options / Customize. I deal with four kinds of operating systems: Russian Windows with a comma as a DS (80%). English Windows with a period as a DS (15%). Russian Windows with a period as a DS to make poorly written English applications work (4%). English Windows with a comma as a DS to make poorly written Russian applications work (1%). All 100% of clients are in Russia and the legacy application deals with Russian goverment-issued forms, so asking for a country will yield 100% of Russian Federation, and GeoIP will yield 80% of Russian Federation and 20% of other, incorrect answers.

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  • jndi binding on jboss4.2.3 and ejb3

    - by broschb
    I am trying to deploy a stateless ejb on jboss 4.2.3 using ejb3 annotations. Everything builds and deploys correctly, and I do not get any errors when jboss starts up. However the ejb is not getting bound to any JNDI location for lookup when I look at the bindings in jboss. Below is what I have for my ejb. Remote @Remote public interface TestWebService { public String TestWebMethod(String param1, String param2); } Stateless EJB @Stateless @RemoteBinding(jndiBinding="TestWeb") @Remote(TestWebService.class) public class TestWebServiceBean implements TestWebService{ public String TestWebMethod(String param1, String param2) { System.out.println("HELLO "+param1+" "+param2); return "Welcome!!"; } } I have tried not having the @Remote and @RemoteBinding and it doesn't make a difference. I have also added and ejb-jar.xml file (which should not be needed with ejb3) and that does not appear to make a difference. Below is the output I see in the jboss log on startup. installing MBean: jboss.j2ee:ear=ejb_web_service_ear-0.0.1- SNAPSHOT.ear,jar=ejb_web_service-0.0.1-SNAPSHOT.jar,name=TestWebServiceBean,service=EJB3 with dependencies: 21:56:00,633 INFO [EJBContainer] STARTED EJB: com.tomax.ejb.TestWebServiceBean ejbName: TestWebServiceBean

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  • Why would I need a using statement to Libary B extn methods, if they're used in Library A & it's Li

    - by Greg
    Hi, I have: Main Program Class - uses Library A Library A - has partial classes which mix in methods from Library B Library B - mix in methods & interfaces Why would I need a using statement to LibaryB just to get their extension methods working in the main class? That is given that it's Library B that defines the classes that will be extended. EDIT - Except from code // *** PROGRAM *** using TopologyDAL; using Topology; // *** THIS WAS NEEDED TO GET EXTN METHODS APPEARING *** class Program { static void Main(string[] args) { var context = new Model1Container(); Node myNode; // ** trying to get myNode mixin methods to appear seems to need using line to point to Library B *** } } // ** LIBRARY A namespace TopologyDAL { public partial class Node { // Auto generated from EF } public partial class Node : INode<int> // to add extension methods from Library B { public int Key } } // ** LIBRARY B namespace ToplogyLibrary { public static class NodeExtns { public static void FromNodeMixin<T>(this INode<T> node) { // XXXX } } public interface INode<T> { // Properties T Key { get; } // Methods } }

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  • Background color remaining when switching views

    - by Guy
    Hi Guys. I have a UIViewController named equationVC who's user interface is being programmatically created from another NSObject class called equationCon. Upon loading equationVC, a method called chooseInterface is called from the equationCon class. I have a global variable (globalVar) that points to a user defined string. chooseInterface finds a method in the equationCon class that matches the string globalVar points to. In this case, let's say that globalVar points to a string that is called "methodThatMatches." In methodThatMatches, another view controller needs to show the results of what methodThatMatches did. methodThatMatches creates a new equationVC that calls upon methodThatMatches2. As a test, each method changes the color of the background. When the application starts up, I get a purple background, but as soon as I hit backwards I get another purple screen, which should be yellow. I do not think that I am release the view properly. Can anyone help? -(void)chooseInterface { NSString* equationTemp = [globalVar stringByReplacingOccurrencesOfString:@" " withString:@""]; equationTemp = [equationTemp stringByReplacingOccurrencesOfString:@"'" withString:@""]; SEL equationName = NSSelectorFromString(equationTemp); NSLog(@"selector! %@",NSStringFromSelector(equationName)); if([self respondsToSelector:equationName]){ [self performSelector:equationName]; } } -(void)methodThatMatches{ self.equationVC.view.backgroundColor = [UIColor yellowColor]; [setGlobalVar:@"methodThatMatches2"]; EquationVC* temp = [[EquationVC alloc] init]; [[self.equationVC navigationController] pushViewController:temp animated:YES ]; [temp release]; } -(void)methodThatmatches2{ self.equationVC.view.backgroundColor = [UIColor purpleColor]; }

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  • What's a good Java-based Master-Slave communication mechanism?

    - by plecong
    I'm creating a Java application that requires master-slave communication between JVMs, possibly residing on the same physical machine. There will be a "master" server running inside a JEE application server (i.e. JBoss) that will have "slave" clients connect to it and dynamically register itself for communication (that is the master will not know the IP addresses/ports of the slaves so cannot be configured in advance). The master server acts as a controller that will dole work out to the slaves and the slaves will periodically respond with notifications, so there would be bi-directional communication. I was originally thinking of RPC-based systems where each side would be a server, but it could get complicated, so I'd prefer a mechanism where there's an open socket and they talk back and forth. I'm looking for a communication mechanism that would be low-latency where the messages would be mostly primitive types, so no serious serialization is necessary. Here's what I've looked at: RMI JMS: Built-in to Java, the "slave" clients would connect to the existing ConnectionFactory in the application server. JAX-WS/RS: Both master and slave would be servers exposing an RPC interface for bi-directional communication. JGroups/Hazelcast: Use shared distributed data structures to facilitate communication. Memcached/MongoDB: Use these as "queues" to facilitate communication, though the clients would have to poll so there would be some latency. Thrift: This does seem to keep a persistent connection, but not sure how to integrate/embed a Thrift server into JBoss WebSocket/Raw Socket: This would work, but require a lot more custom code than I'd like. Is there any technology I'm missing? Edit: Also looked at: JMX: Have the client connect to JBoss' JMX server and receive JMX notifications for bidirectional comms.

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  • Modelbinding using Interfaces in ASP.NET MVC 2

    - by Thomas
    I have the following View Data: public class ShoppingCartViewData { public IList<IShoppingCartItem> Cart { get; set; } } I populate the viewdata in my controller: viewData.Cart = CurrentSession.CartItems; return View(viewData); And send the data to the view and display it using: <% for (int i = 0; i < Model.Cart.Count; i++ ) { %> <%= Html.TextBoxFor(m => m.Cart[i].Quantity)%> <%= Html.HiddenFor(m => m.Cart[i].Id) %> <% } %> I want to be able to catch the viewdata on the post. When I try: [HttpPost] public ActionResult UpdateCart(ShoppingCartViewData viewData) { ... } When I run this I get a: System.MissingMethodException: Cannot create an instance of an interface. Can anyone shed some light on this. What would I have to do to get this to work? Many Thanks

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  • IDE framework for a dynamic language?

    - by Kevin Reid
    Let's say I have a super-wonderful new programming language, and I want there to be an IDE for it. What IDE platform/framework could I use to get this done efficiently? I mean things like: Collection of files in a project, searching them, tabbed/split editors etc. — the basics. Syntax highlighting and auto-indent/reformatting. Providing the user interface for code completion — hit tab, get a list (I'll have to implement the necessary partial evaluation myself (it's a dynamic language)). This is the feature I'm most wishing for. Built-in parser framework which is good at recovering from the sort of syntax errors occurring in code that is in the middle of being edited would be helpful. In-editor annotation of syntax/runtime error locations fed back from the language runtime. REPL (interactive evaluator) interaction with the same completion as in the editor. This system should be Linux/Mac/Windows cross-platform (in that priority order). Being implemented in Java (or rather, accepting language plugins written in Java) is possibly useful, but anything else is worth a try too.

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  • Deep Zoom in Ajax - Possible? Any examples out there?

    - by Phil
    I have an idea to implement a deep zoom type interface hosted in a browser for sports training data (speed, distance, heart rate etc.) However, rather than images I actually want to zoom into a hierarchy of information. For example, the initial display would contain a grid of years - hover over 2008, for example, and spin the mouse wheel (or click) will zoom into that year but during the zoom I want 2008 to fade out and be replaced with a calendar of months. Again zoom into a month and the months are replaced with the months calendar, zoom into a day and you finally see a chart with the training data plotted on it. All the time only dates with actual data would be highlighted in some fashion. My question is whether this would even be possible and whether anyone has seen examples of this already. I'm imagining that most of the time the next level of information could be cached in the browser (in fact, because this is calendar-based, I can calculate most of that and cache the dates to be highlighted.) I could also zoom into an empty chart whilst an Ajax thread is fetching the data to display. I've never tried anything like this before and I'm especially interested in whether DHTML would be capable of this sort of zoom (I suspect not and I would have to resort to Silverlight) and whether the Ajax execution would be uninterrupted whilst the browser rendering thread is kept busy zooming.

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  • How to customize the process employed by WCF when serializing contract method arguments?

    - by mark
    Dear ladies and sirs. I would like to formulate a contrived scenario, which nevertheless has firm actual basis. Imagine a collection type COuter, which is a wrapper around an instance of another collection type CInner. Both implement IList (never mind the T). Furthermore, a COuter instance is buried inside some object graph, the root of which (let us refer to it as R) is returned from a WCF service method. My question is how can I customize the WCF serialization process, so that when R is returned, the request to serialize the COuter instance will be routed through my code, which will extract CInner and pass it to the serializer instead. Thus the receiving end still gets R, only no COuter instance is found in the object graph. I hoped that http://stackoverflow.com/questions/2220516/how-does-wcf-serialize-the-method-call will contain the answer, unfortunately the article mentioned there (http://msdn.microsoft.com/en-us/magazine/cc163569.aspx) only barely mentions that advanced serialization scenarios are possible using IDataContractSurrogate interface, but no details are given. I am, on the other hand, would really like to see a working example. Thank you very much in advance.

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  • What VC++ compiler/linker does when building a C++ project with Managed Extension

    - by ???
    The initial problem is that I tried to rebuild a C++ project with debug symbols and copied it to test machine, The output of the project is external COM server(.exe file). When calling the COM interface function, there's a RPC call failre: COMException(0x800706BE): The remote procedure call failed. According to the COM HRESULT design, if the FACILITY code is 7, it's actually a WIN32 error, and the win32 error code is 0x6BE, which is the above mentioned "remote procedure call failed". All I do is replace the COM server .exe file, the origin file works well. When I checked into the project, I found it's a C++ project with Managed Extension. When I checking the DLL with reflector, it shows there's 2 additional .NET assembly reference. Then I checked the project setting and found nothing about the extra 2 assembly reference. I turned on the show includes option of compiler and verbose library of linker, and try to analyze whether the assembly is indirectly referenced via .h file. I've collect all the .h file and grep all the files with '#using' '#import' and the assembly file itself. There really is a '#using ' in one of the .h file but not-relevant to the referenced assembly. And about the linked .lib library files, only one of the .lib file is a side-product of another managed-extension-enabled C++ project, all others are produced by a pure, traditional C++ project. For the managed-extension-enabled C++ project, I checked the output DLL assembly, it did NOT reference to the 2 assembly. I even try to capture the access of the additional assembly file via sysinternal's filemon and procmon, but the rebuild process does NOT access these file. I'm very confused about the compile and linking process model of a VC++/CLI project, where the additional assembly reference slipped into the final assembly? Thanks in advance for any of your help.

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