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• Unable to display Google Map through API in Flex SDK

  - by Spero.ShiroPetto

  Hello, I am using the mxmlc to compile the examples from google to get started in using Google Maps API in Flex 4. But after compiling the swf file the map does not load. I've registered for an API key Downloaded and included the Maps SDK in the xml config file used at compile time C:\sdk\flex4\frameworks\flex-config.xml <external-library-path> <path-element>libs/google/maps/lib/map_flex_1_18.swc</path-element> </external-library-path> Foo.mxml <?xml version="1.0" encoding="utf-8"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute"> <maps:Map xmlns:maps="com.google.maps.*" id="map" mapevent_mapready="onMapReady(event)" width="100%" height="100%" key="{KEY}"/> <mx:Script> <![CDATA[ import com.google.maps.LatLng; import com.google.maps.Map; import com.google.maps.MapEvent; import com.google.maps.MapType; private function onMapReady(event:Event):void { this.map.setCenter(new LatLng(40.736072,-73.992062), 14, MapType.NORMAL_MAP_TYPE); } ]]> </mx:Script> </mx:Application> Any tips on where to go from here? I can compile a basic flex project without problem and displays the components I put in so i'd imagine it's something to do with the API Key? Thanks for the help

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• How do i refactor this code by using Action<t> or Func<t> delegates

  - by user330612

  I have a sample program, which needs to execute 3 methods in a particular order. And after executing each method, should do error handling. Now i did this in a normal fashion, w/o using delegates like this. class Program { public static void Main() { MyTest(); } private static bool MyTest() { bool result = true; int m = 2; int temp = 0; try { temp = Function1(m); } catch (Exception e) { Console.WriteLine("Caught exception for function1" + e.Message); result = false; } try { Function2(temp); } catch (Exception e) { Console.WriteLine("Caught exception for function2" + e.Message); result = false; } try { Function3(temp); } catch (Exception e) { Console.WriteLine("Caught exception for function3" + e.Message); result = false; } return result; } public static int Function1(int x) { Console.WriteLine("Sum is calculated"); return x + x; } public static int Function2(int x) { Console.WriteLine("Difference is calculated "); return (x - x); } public static int Function3(int x) { return x * x; } } As you can see, this code looks ugly w/ so many try catch loops, which are all doing the same thing...so i decided that i can use delegates to refactor this code so that Try Catch can be all shoved into one method so that it looks neat. I was looking at some examples online and couldnt figure our if i shud use Action or Func delegates for this. Both look similar but im unable to get a clear idea how to implement this. Any help is gr8ly appreciated. I'm using .NET 4.0, so im allowed to use anonymous methods n lambda expressions also for this Thanks

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• Why is my GZipStream not writeable?

  - by Ozzah

  I have some GZ compressed resources in my program and I need to be able to write them out to temporary files for use. I wrote the following function to write the files out and return true on success or false on failure. In addition, I've put a try/catch in there which shows a MessageBox in the event of an error: private static bool extractCompressedResource(byte[] resource, string path) { try { using (MemoryStream ms = new MemoryStream(resource)) { using (FileStream fs = new FileStream(path, FileMode.Create, FileAccess.ReadWrite)) { using (GZipStream zs = new GZipStream(fs, CompressionMode.Decompress)) { ms.CopyTo(zs); // Throws exception zs.Close(); ms.Close(); } } } } catch (Exception ex) { MessageBox.Show(ex.Message); // Stream is not writeable return false; } return true; } I've put a comment on the line which throws the exception. If I put a breakpoint on that line and take a look inside the GZipStream then I can see that it's not writeable (which is what's causing the problem). Am I doing something wrong, or is this a limitation of the GZipStream class?

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• revoked client certificate

  - by Michael

  Hi guys, I have little problem. I used certificate authority in windows server 2003 and revoked client certificate. The client certificate is in revoked certificate. I try verify this client certificate on revocation in winform app in windows server 2003. Code is here : private bool VefiryCert(X509Certificate2 cert) { X509Chain chain = new X509Chain(); chain.ChainPolicy.RevocationFlag = X509RevocationFlag.EntireChain; chain.ChainPolicy.RevocationMode = X509RevocationMode.Online; chain.ChainPolicy.UrlRetrievalTimeout = new TimeSpan(0, 0, 1000); chain.ChainPolicy.VerificationFlags = X509VerificationFlags.AllFlags; X509VerificationFlags.AllowUnknownCertificateAuthority; return chain.Build(cert); } But this client certificate is verify as true. I am confuse, where can be problem ? How can I check revocation list, which is loaded in winform application and used on verification this client certificate? So the problem is I verify client certificate, which is in revoked list (in certification authority) with method VefiryCert, an the certificate is verify as TRUE. Can somebody help me ?

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• C# Using Enumerable Range and Except with custom class to determine missing sequence number

  - by Jon

  I have a List<MyClass> The class is like this: private class MyClass { public string Name{ get; set; } public int SequenceNumber { get; set; } } I want to work out what Sequence numbers might be missing. I can see how to do this here however because this is a class I am unsure what to do? I think I can handle the except method ok with my own IComparer but the Range method I can't figure out because it only excepts int so this doesn't compile: Enumerable.Range(0, 1000000).Except(chqList, MyEqualityComparer<MyClass>); Here is the IComparer: public class MyEqualityComparer<T> : IEqualityComparer<T> where T : MyClass { #region IEqualityComparer<T> Members public bool Equals(T x, T y) { return (x == null && y == null) || (x != null && y != null && x.SequenceNumber.Equals(y.SequenceNumber)); } /// </exception> public int GetHashCode(T obj) { if (obj == null) { throw new ArgumentNullException("obj"); } return obj.GetHashCode(); } #endregion }

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• Windows Phone - OnNavigatingFrom - problem

  - by Martin Anderson

  I believe this is just a problem for me, due to my lack of programming ability. I am currently exploring transitions between page navigation with Windows Phone apps. I was originally using storyboards, and completed event handlers to have my pages animate on and off screen. These leads to the a problem when you want to navigate to many pages from one page, using the same transition. So I have started looking at OnNavigatedTo, and OnNavigatingFrom events and while it is working nicely for OnNavigatedTo, the later just wont work. It seems the Microsoft.Phone.Navigation assembly does not contain OnNavigatingFrom, and referencing System.Windows.Navigation, compiles ok, but I cant get pages to animate off upon navigation. I have a button on my Page2, which I want to go back to my MainPage (after I over-rided the back key with a message box for testing). I have transitions made on the page, and I have this as the event handler code... private void btnP2_BackToP1Clicked(object sender, System.Windows.RoutedEventArgs e) { NavigationService.Navigate(new Uri("/MainPage.xaml", UriKind.Relative)); } With this code for the OnNavigatedTo and OnNavigatingFrom events... protected override void OnNavigatedTo(PhoneNavigationEventArgs e) { PageTransition_In.Begin(); } // // protected override void OnNavigatingFrom(NavigatingCancelEventArgs e) { PageTransition_Out.Begin(); base.OnNavigatingFrom(e); } I have the feeling that OnNavigatingFrom may not(yet) be supported for Windows Phone Apps. OnNavigatedFrom is part of Microsoft.Phone.Navigation, but it only performs actions once the page is no longer active, which is too late to perform any animation effects.

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• In WPF, accessing containers within ListBox

  - by Jim

  I'm creating a DerivedListBox : ListBox and a DerivedHeaderedContentControl : HeaderedContentControl, which will serve as a container for each item in the ListBox. In order to calculate the size available for the expanded content of the DerivedHeaderedContentControls, I am storing each container object in a list within the DerivedListBox. This way I can calculate the height of the headers of each DerivedHeaderedContentControl and subtract that from the total size available to the DerivedListBox. This would be the size available for the expanded content of a DerivedHeaderedContentControl. public class DerivedHeaderedContentControl : HeaderedContentControl { // Do some binding to DerivedListBox to calculate height. } public class DerivedListBox : ListBox { private List<DerivedHeaderedContentControl> containers; protected override DependencyObject GetContainerForItemOverride() { DerivedHeaderedContentControl val = new DerivedHeaderedContentControl(); this.containers.Add(val); return val; } // Do some binding to calculate height available for an expanded // container by iterating over containers. } The problem comes in when the DerivedListBox's ItemsSource is cleared (or an item in the items source is removed). How can I determine when the ItemsSource is cleared so that I can clear the containers list?

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• How can I get this dynamic WHERE statement in my LINQ-to-XML to work?

  - by Edward Tanguay

  In this question Jon Skeet offered a very interesting solution to making a LINQ-to-XML statement dynamic, but my knowledge of lambdas and delegates is not yet advanced enough to implement it: I've got it this far, but of course I get the error "smartForm does not exist in the current context": private void LoadWithId(int id) { XDocument xmlDoc = null; try { xmlDoc = XDocument.Load(FullXmlDataStorePathAndFileName); } catch (Exception ex) { throw new Exception(String.Format("Cannot load XML file: {0}", ex.Message)); } Func<XElement, bool> whereClause = (int)smartForm.Element("id") == id"; var smartForms = xmlDoc.Descendants("smartForm") .Where(whereClause) .Select(smartForm => new SmartForm { Id = (int)smartForm.Element("id"), WhenCreated = (DateTime)smartForm.Element("whenCreated"), ItemOwner = smartForm.Element("itemOwner").Value, PublishStatus = smartForm.Element("publishStatus").Value, CorrectionOfId = (int)smartForm.Element("correctionOfId"), IdCode = smartForm.Element("idCode").Value, Title = smartForm.Element("title").Value, Description = smartForm.Element("description").Value, LabelWidth = (int)smartForm.Element("labelWidth") }); foreach (SmartForm smartForm in smartForms) { _collection.Add(smartForm); } } Ideally I want to be able to just say: var smartForms = GetSmartForms(smartForm=> (int) smartForm.Element("DisplayOrder").Value > 50); I've got it this far, but I'm just not grokking the lambda magic, how do I do this? public List<SmartForm> GetSmartForms(XDocument xmlDoc, XElement whereClause) { var smartForms = xmlDoc.Descendants("smartForm") .Where(whereClause) .Select(smartForm => new SmartForm { Id = (int)smartForm.Element("id"), WhenCreated = (DateTime)smartForm.Element("whenCreated"), ItemOwner = smartForm.Element("itemOwner").Value, PublishStatus = smartForm.Element("publishStatus").Value, CorrectionOfId = (int)smartForm.Element("correctionOfId"), IdCode = smartForm.Element("idCode").Value, Title = smartForm.Element("title").Value, Description = smartForm.Element("description").Value, LabelWidth = (int)smartForm.Element("labelWidth") }); }

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• C++ -- Is there an implicit cast here from Fred* to auto_ptr<Fred>?

  - by q0987

  Hello all, I saw the following code, #include <new> #include <memory> using namespace std; class Fred; // Forward declaration typedef auto_ptr<Fred> FredPtr; class Fred { public: static FredPtr create(int i) { return new Fred(i); // Is there an implicit casting here? If not, how can we return // a Fred* with return value as FredPtr? } private: Fred(int i=10) : i_(i) { } Fred(const Fred& x) : i_(x.i_) { } int i_; }; Please see the question listed in function create. Thank you // Updated based on comments Yes, the code cannot pass the VC8.0 error C2664: 'std::auto_ptr<_Ty::auto_ptr(std::auto_ptr<_Ty &) throw()' : cannot convert parameter 1 from 'Fred *' to 'std::auto_ptr<_Ty &' The code was copied from the C++ FAQ 12.15. However, after making the following changes, replace return new Fred(i); with return auto_ptr<Fred>(new Fred(i)); This code can pass the VC8.0 compiler. But I am not sure whether or not this is a correct fix.

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• Simple in-place discrete fourier transform ( DFT )

  - by Adam

  I'm writing a very simple in-place DFT. I am using the formula shown here: http://en.wikipedia.org/wiki/Discrete_Fourier_transform#Definition along with Euler's formula to avoid having to use a complex number class just for this. So far I have this: private void fft(double[] data) { double[] real = new double[256]; double[] imag = new double[256]; double pi_div_128 = -1 * Math.PI / 128; for (int k = 0; k < 256; k++) { for (int n = 0; n < 256; n++) { real[k] += data[k] * Math.Cos(pi_div_128 * k * n); imag[k] += data[k] * Math.Sin(pi_div_128 * k * n); } data[k] = Math.Sqrt(real[k] * real[k] + imag[k] * imag[k]); } } But the Math.Cos and Math.Sin terms eventually go both positive and negative, so as I'm adding those terms multiplied with data[k], they cancel out and I just get some obscenely small value. I see how it is happening, but I can't make sense of how my code is perhaps mis-representing the mathematics. Any help is appreciated. FYI, I do have to write my own, I realize I can get off-the shelf FFT's.

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• Creating ListView with check boxes...Android

  - by deewangan

  Hello, I am trying to create a listview that has check box beside each item. (i am following a code from the book android), but i can't get it to work, every time i run it, it crashes. since i am very new to this android staff, i have no clue what to do to get it to work, any help is appreciated.the code is below. *i have created two layout files in names of list and list_item. the code for the main activity: public class ListDemoActivity extends ListActivity { /** Called when the activity is first created. */ String[] listItems = {"exploring", "android","list", "activities"}; private SimpleCursorAdapter adapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.lists); //setListAdapter(new ArrayAdapter(this,android.R.layout.simple_list_item_1, listItems)); //setContentView(R.layout.lists); Cursor c = getContentResolver().query(People.CONTENT_URI, null, null, null, null); startManagingCursor(c); String[] cols = new String[]{People.NAME}; int[] names = new int[]{R.id.row_tv}; adapter = new SimpleCursorAdapter(this,R.layout.list_item,c,cols,names); this.setListAdapter(adapter); } } the lists file content: <?xml version="1.0" encoding="utf-8"?> and the list_item file content: <?xml version="1.0" encoding="utf-8"?>

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• In asp.Net, writing code in the control tag generates compile error

  - by Nour Sabouny

  Hi this is really strange !! But look at the following asp code: <div runat="server" id="MainDiv"> <%foreach (string str in new string[]{"First#", "Second#"}) { %> <div id="<%=str.Replace("#","div") %>"> </div> <%} %> </div> now if you put this code inside any web page (and don't worry about the moral of this code, I made it just to show the idea) you'll get this error : Compiler Error Message: CS1518: Expected class, delegate, enum, interface, or struct Of course the error has nothing to do with the real problem, I searched for the code that was generated by asp.net and figured out the following : private void @__RenderMainDiv(System.Web.UI.HtmlTextWriter @__w, System.Web.UI.Control parameterContainer) { @__w.Write("\r\n "); #line 20 "blabla\blabla\Default.aspx" foreach (string str in new string[] { "First#", "Second#" }) { #line default #line hidden @__w.Write("\r\n <div id=\""); #line 22 "blabla\blabla\Default.aspx" @__w.Write(str.Replace("#", "div")); #line default #line hidden @__w.Write("\">\r\n "); } This is the code that was generated from the asp page and this is the method that is meant to render our div (MainDiv), I found out that there is a missing bracket "}" that closes the method or the (for loop). now the problem has three parts: 1- first you should have a server control (in our situation is the MainDiv) and I'm not sure if it is only the div tag. 2- HTML control inside the server control and a code inside it using the double quotation mark ( for example <div id="<%=str instead of <div id='<%=str. 3-Any keyword which has block brackets e.g.:for{},while{},using{}...etc. now removing any part, will solve the problem !!! how is this happening ?? any ideas ? BTW: please help me to make the question more obvious, because I couldn't find the best words to describe the problem.

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• How can I use nested Async (WCF) calls within foreach loops in Silverlight ?

  - by Peter St Angelo

  The following code contains a few nested async calls within some foreach loops. I know the silverlight/wcf calls are called asyncrously -but how can I ensure that my wcfPhotographers, wcfCategories and wcfCategories objects are ready before the foreach loop start? I'm sure I am going about this all the wrong way -and would appreciate an help you could give. private void PopulateControl() { List<CustomPhotographer> PhotographerList = new List<CustomPhotographer>(); proxy.GetPhotographerNamesCompleted += proxy_GetPhotographerNamesCompleted; proxy.GetPhotographerNamesAsync(); //for each photographer foreach (var eachPhotographer in wcfPhotographers) { CustomPhotographer thisPhotographer = new CustomPhotographer(); thisPhotographer.PhotographerName = eachPhotographer.ContactName; thisPhotographer.PhotographerId = eachPhotographer.PhotographerID; thisPhotographer.Categories = new List<CustomCategory>(); proxy.GetCategoryNamesFilteredByPhotographerCompleted += proxy_GetCategoryNamesFilteredByPhotographerCompleted; proxy.GetCategoryNamesFilteredByPhotographerAsync(thisPhotographer.PhotographerId); // for each category foreach (var eachCatergory in wcfCategories) { CustomCategory thisCategory = new CustomCategory(); thisCategory.CategoryName = eachCatergory.CategoryName; thisCategory.CategoryId = eachCatergory.CategoryID; thisCategory.SubCategories = new List<CustomSubCategory>(); proxy.GetSubCategoryNamesFilteredByCategoryCompleted += proxy_GetSubCategoryNamesFilteredByCategoryCompleted; proxy.GetSubCategoryNamesFilteredByCategoryAsync(thisPhotographer.PhotographerId,thisCategory.CategoryId); // for each subcategory foreach(var eachSubCatergory in wcfSubCategories) { CustomSubCategory thisSubCatergory = new CustomSubCategory(); thisSubCatergory.SubCategoryName = eachSubCatergory.SubCategoryName; thisSubCatergory.SubCategoryId = eachSubCatergory.SubCategoryID; } thisPhotographer.Categories.Add(thisCategory); } PhotographerList.Add(thisPhotographer); } PhotographerNames.ItemsSource = PhotographerList; } void proxy_GetPhotographerNamesCompleted(object sender, GetPhotographerNamesCompletedEventArgs e) { wcfPhotographers = e.Result.ToList(); } void proxy_GetCategoryNamesFilteredByPhotographerCompleted(object sender, GetCategoryNamesFilteredByPhotographerCompletedEventArgs e) { wcfCategories = e.Result.ToList(); } void proxy_GetSubCategoryNamesFilteredByCategoryCompleted(object sender, GetSubCategoryNamesFilteredByCategoryCompletedEventArgs e) { wcfSubCategories = e.Result.ToList(); }

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• Qt Jambi: Accessing the content of QNetworkReply

  - by Richard

  Hi All, I'm having trouble accessing the content of QNetworkReply objects. Content appears to be empty or zero. According to the docs (translating from c++ to java) I think I've got this set up correctly, but to no avail. Additionally an "Unknown error" is being reported. Any ideas much appreciated. Code: public class Test extends QObject { private QWebPage page; public Test() { page = new QWebPage(); QNetworkAccessManager nac = new QNetworkAccessManager(); nac.finished.connect(this, "requestFinished(QNetworkReply)"); page.setNetworkAccessManager(nac); page.loadProgress.connect(this, "loadProgress(int)"); page.loadFinished.connect(this, "loadFinished()"); } public void requestFinished(QNetworkReply reply) { reply.reset(); reply.open(OpenModeFlag.ReadOnly); reply.readyRead.connect(this, "ready()"); // never gets called System.out.println("bytes: " + reply.url().toString()); // writes out asset uri no problem System.out.println("bytes: " + reply.bytesToWrite()); // 0 System.out.println("At end: " + reply.atEnd()); // true System.out.println("Error: " + reply.errorString()); // "Unknown error" } public void loadProgress(int progress) { System.out.println("Loaded " + progress + "%"); } public void loadFinished() { System.out.println("Done"); } public void ready() { System.out.println("Ready"); } public void open(String url) { page.mainFrame().load(new QUrl(url)); } public static void main(String[] args) { QApplication.initialize(new String[] { }); Test t = new Test(); t.open("http://news.bbc.co.uk"); QApplication.exec(); } }

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• Object not declared in scope

  - by jay

  I'm using Xcode for C++ on my computer while using Visual Studio at school. The following code worked just fine in Visual Studio, but I'm having this problem when using Xcode. clock c1(2, 3, 30); Everything works just fine, but it keeps giving me this error that says "Expected ';' before 'c1'" Fine, I put the ';' .. but then, it gives me this error: "'c1' was not declared in this scope" Here's the whole header code: #include <iostream> using namespace std; class clock { private: int h; int m; int s; public: clock(int hr, int mn, int sec); }; clock::clock(int hr, int mn, int sec) { h = hr; m = mn; s = sec; } Here's the whole .cpp code: #include "clock.h" int main() { clock c1(2, 3, 30); return 0; } I stripped everything down to where I had the problem. Everything else, as far as I know, is irrelevant since the problem remains the same with just the mentioned above. Thanks in advance!

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• MVC.NET custom validator is not working

  - by IvanMushketyk

  I want to write a custom validator for MVC.NET framework that checks if entered date is in the future. To do it, I wrote the following class: [AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)] public sealed class InTheFutureAttribute : ValidationAttribute, IClientValidatable { private const string DefaultErrorMessage = "{0} should be date in the future"; public InTheFutureAttribute() : base(DefaultErrorMessage) { } public override string FormatErrorMessage(string name) { return string.Format(ErrorMessageString, name); } public override bool IsValid(object value) { DateTime time = (DateTime)value; if (time < DateTime.Now) { return false; } return true; } public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context) { var clientValidationRule = new ModelClientValidationRule() { ErrorMessage = FormatErrorMessage(metadata.GetDisplayName()), ValidationType = "wrongvalue" }; return new[] { clientValidationRule }; } } and added attribute to field that I want to check. On the View page I create input field in the following way: <div class="editor-label-search"> @Html.LabelFor(model => model.checkIn) </div> <div class="editor-field-search-date"> @Html.EditorFor(model => model.checkIn) <script type="text/javascript"> $(document).ready(function () { $('#checkIn').datepicker({ showOn: 'button', buttonImage: '/Content/images/calendar.gif', duration: 0, dateFormat: 'dd/mm/yy' }); }); </script> @Html.ValidationMessageFor(model => model.checkIn) </div> When I submit the form for the controller that requires model with checked attribute code in my validator is called and it returns false, but instead of displaying an error it just call my controller's action and send invalid model to it. Am I doing something wrong? How can I fix it? Thank you in advance.

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• Can Castle.Windsor do automatic resolution of concrete types

  - by Anthony

  We are evaluating IoC containers for C# projects, and both Unity and Castle.Windsor are standing out. One thing that I like about Unity (NInject and StructureMap also do this) is that types where it is obvious how to construct them do not have to be registered with the IoC Container. Is there way to do this in Castle.Windsor? Am I being fair to Castle.Windsor to say that it does not do this? Is there a design reason to deliberately not do this, or is it an oversight, or just not seen as important or useful? I am aware of container.Register(AllTypes... in Windsor but that's not quite the same thing. It's not entirely automatic, and it's very broad. To illustrate the point, here are two NUnit tests doing the same thing via Unity and Castle.Windsor. The Castle.Windsor one fails. : namespace SimpleIocDemo { using NUnit.Framework; using Castle.Windsor; using Microsoft.Practices.Unity; public interface ISomeService { string DoSomething(); } public class ServiceImplementation : ISomeService { public string DoSomething() { return "Hello"; } } public class RootObject { public ISomeService SomeService { get; private set; } public RootObject(ISomeService service) { SomeService = service; } } [TestFixture] public class IocTests { [Test] public void UnityResolveTest() { UnityContainer container = new UnityContainer(); container.RegisterType<ISomeService, ServiceImplementation>(); // Root object needs no registration in Unity RootObject rootObject = container.Resolve<RootObject>(); Assert.AreEqual("Hello", rootObject.SomeService.DoSomething()); } [Test] public void WindsorResolveTest() { WindsorContainer container = new WindsorContainer(); container.AddComponent<ISomeService, ServiceImplementation>(); // fails with exception "Castle.MicroKernel.ComponentNotFoundException: // No component for supporting the service SimpleIocDemo.RootObject was found" // I could add // container.AddComponent<RootObject>(); // but that approach does not scale RootObject rootObject = container.Resolve<RootObject>(); Assert.AreEqual("Hello", rootObject.SomeService.DoSomething()); } } }

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• Design pattern to use instead of multiple inheritance

  - by mizipzor

  Coming from a C++ background, Im used to multiple inheritance. I like the feeling of a shotgun squarely aimed at my foot. Nowadays, I work more in C# and Java, where you can only inherit one baseclass but implement any number of interfaces (did I get the terminology right?). For example, lets consider two classes that implement a common interface but different (yet required) baseclasses: public class TypeA : CustomButtonUserControl, IMagician { public void DoMagic() { // ... } } public class TypeB : CustomTextUserControl, IMagician { public void DoMagic() { // ... } } Both classes are UserControls so I cant substitute the base class. Both needs to implement the DoMagic function. My problem now is that both implementations of the function are identical. And I hate copy-and-paste code. The (possible) solutions: I naturally want TypeA and TypeB to share a common baseclass, where I can write that identical function definition just once. However, due to having the limit of just one baseclass, I cant find a place along the hierarchy where it fits. One could also try to implement a sort of composite pattern. Putting the DoMagic function in a separate helper class, but the function here needs (and modifies) quite a lot of internal variables/fields. Sending them all as (reference) parameters would just look bad. My gut tells me that the adapter pattern could have a place here, some class to convert between the two when necessery. But it also feels hacky. I tagged this with language-agnostic since it applies to all languages that use this one-baseclass-many-interfaces approach. Also, please point out if I seem to have misunderstood any of the patterns I named. In C++ I would just make a class with the private fields, that function implementation and put it in the inheritance list. Whats the proper approach in C#/Java and the like?

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• How to architect Rails site that can be edited while running?

  - by Chris Kimpton

  Hi, I am writing a Rails app that "scrapes/navigates" some other websites and webservices for content. I am using Mechanize and Savon to do the heavylifting. But given the dynamic nature of the web, I'd like to make my calls to these editable by the admin users of the site - rather than requiring me to release a new version of the site. The actual scraping thread happens async to the website, using the daemons gem. My requirements are: Thinking that the scraping/webservice calling code is quite simple, the easiest route is to make the whole class editable by the admins. Keep a history of the scraping code - so that we can fairly easily revert if we introduce a problem. Initially use the code from the file system, but as soon as thats been edited and stored somewhere, to use that code instead. I am thinking my options are: Store the code in the db (with a history table for the old versions) Store the code in a private git repo somewhere and access that for the history/latest versions. I am thinking the git route might be easiest, given its raison d'etre is to track file history... But perhaps there is a gem/plugin that does all this for me, out of the box? Thanks in advance for any tips/advice. ~chris

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• List.Sort in C#: comparer being called with null object

  - by cbp

  I am getting strange behaviour using the built-in C# List.Sort function with a custom comparer. For some reason it sometimes calls the comparer class's Compare method with a null object as one of the parameters. But if I check the list with the debugger there are no null objects in the collection. My comparer class looks like this: public class DelegateToComparer<T> : IComparer<T> { private readonly Func<T,T,int> _comparer; public int Compare(T x, T y) { return _comparer(x, y); } public DelegateToComparer(Func<T, T, int> comparer) { _comparer = comparer; } } This allows a delegate to be passed to the List.Sort method, like this: mylist.Sort(new DelegateToComparer<MyClass>( (x, y) => { return x.SomeProp.CompareTo(y.SomeProp); }); So the above delegate will throw a null reference exception for the x parameter, even though no elements of mylist are null. UPDATE: Yes I am absolutely sure that it is parameter x throwing the null reference exception! UPDATE: Instead of using the framework's List.Sort method, I tried a custom sort method (i.e. new BubbleSort().Sort(mylist)) and the problem went away. As I suspected, the List.Sort method passes null to the comparer for some reason.

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• a problem in socks.h

  - by janathan

  i use this (http://www.codeproject.com/KB/IP/Socks.aspx) lib in my socket programing in c++ and copy the socks.h in include folder and write this code: include include include include include include "socks.h" define PORT 1001 // the port client will be connecting to define MAXDATASIZE 100 static void ReadThread(void* lp); int socketId; int main(int argc, char* argv[]) { const char temp[]="GET / HTTP/1.0\r\n\r\n"; CSocks cs; cs.SetVersion(SOCKS_VER4); cs.SetSocksPort(1080); cs.SetDestinationPort(1001); cs.SetDestinationAddress("192.168.11.97"); cs.SetSocksAddress("192.168.11.97"); //cs.SetVersion(SOCKS_VER5); //cs.SetSocksAddress("128.0.21.200"); socketId = cs.Connect(); // if failed if (cs.m_IsError) { printf( "\n%s", cs.GetLastErrorMessage()); getch(); return 0; } // send packet for requesting to a server if(socketId > 0) { send(socketId, temp, strlen(temp), 0); HANDLE ReadThreadID; // handle for read thread id HANDLE handle; // handle for thread handle handle = CreateThread ((LPSECURITY_ATTRIBUTES)NULL, // No security attributes. (DWORD)0, // Use same stack size. (LPTHREAD_START_ROUTINE)ReadThread, // Thread procedure. (LPVOID)(void*)NULL, // Parameter to pass. (DWORD)0, // Run immediately. (LPDWORD)&ReadThreadID); WaitForSingleObject(handle, INFINITE); } else { printf("\nSocks Server / Destination Server not started.."); } closesocket(socketId); getch(); return 0; } // Thread Proc for reading from server socket. static void ReadThread(void* lp) { int numbytes; char buf[MAXDATASIZE]; while(1) { if ((numbytes=recv(socketId, buf, MAXDATASIZE-1, 0)) == -1) { printf("\nServer / Socks Server has been closed Receive thread Closed\0"); break; } if (numbytes == 0) break; buf[numbytes] = '\0'; printf("Received: %s\r\n",buf); send(socketId,buf,strlen(buf),0); } } but when compile this i get an error . pls help me thanks

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• Boost::Mutex & Malloc

  - by M. Tibbits

  Hi all, I'm trying to use a faster memory allocator in C++. I can't use Hoard due to licensing / cost. I was using NEDMalloc in a single threaded setting and got excellent performance, but I'm wondering if I should switch to something else -- as I understand things, NEDMalloc is just a replacement for C-based malloc() & free(), not the C++-based new & delete operators (which I use extensively). The problem is that I now need to be thread-safe, so I'm trying to malloc an object which is reference counted (to prevent excess copying), but which also contains a mutex pointer. That way, if you're about to delete the last copy, you first need to lock the pointer, then free the object, and lastly unlock & free the mutex. However, using malloc to create a boost::mutex appears impossible because I can't initialize the private object as calling the constructor directly ist verboten. So I'm left with this odd situation, where I'm using new to allocate the lock and nedmalloc to allocate everything else. But when I allocate a large amount of memory, I run into allocation errors (which disappear when I switch to malloc instead of nedmalloc ~ but the performance is terrible). My guess is that this is due to fragmentation in the memory and an inability of nedmalloc and new to place nice side by side. There has to be a better solution. What would you suggest?

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• android : bluetooth support

  - by Puneet kaur

  i have coded for bluetooth via defining a user task ,which will search the devices in background and set the list on foreground after finishing the search . but sometimes i am getting the data in adapter as "nodevice" "device1" "device2" ...... the problem here is why it is always filling the no device in the list and after that fill the device in list .. private BroadcastReceiver mBlueToothInfoDiscoveryListener = new BroadcastReceiver() { /** * This is an overridden function called by the framework whenever there * is some broadcast message for Bluetooth info discovery listener */ @Override public void onReceive(Context context, Intent intent) { String action = intent.getAction(); // When discovery finds a device if (BluetoothDevice.ACTION_FOUND.equals(action)) { // Get the BluetoothDevice object from the Intent BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE); // If it's already paired, skip it, because it's been listed // already if (device.getBondState() != BluetoothDevice.BOND_BONDED) { mNewBtDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress()); } // When discovery is finished, change the Activity title } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) { setProgressBarIndeterminateVisibility(false); setTitle("device list"); if (mNewBtDevicesArrayAdapter.getCount() == 0) { String noDevices = "No devices found"; mNewBtDevicesArrayAdapter.add(noDevices); } } } }; but here why it is sometimes going into else option on start and filling the list with no device then to if part again ... when devices are already on .

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• printf and Console.WriteLine - problems with Console.SetOut?

  - by Matt Jacobsen

  i have a bunch of Console.WriteLines in my code that I can observe at runtime. I communicate with a native library that I also wrote. I'd like to stick some printf's in the native library and observe them too. I don't see them at runtime however. I've created a convoluted hello world app to demonstrate my problem. When the app runs, I can debug into the native library and see that the hello world is called. The output never lands in the textwriter though. Note that if the same code is run as a console app then everything works fine. C#: [DllImport("native.dll")] static extern void Test(); StreamWriter writer; public Form1() { InitializeComponent(); writer = new StreamWriter(@"c:\output.txt"); writer.AutoFlush = true; System.Console.SetOut(writer); } private void button1_Click(object sender, EventArgs e) { Test(); } and the native part: __declspec(dllexport) void Test() { printf("Hello World"); } Despite my earlier ramblings (see edits) I actually think this is a problem in C# (or rather my understanding of it).

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• Reformat SQLGeography polygons to JSON

  - by James

  I am building a web service that serves geographic boundary data in JSON format. The geographic data is stored in an SQL Server 2008 R2 database using the geography type in a table. I use [ColumnName].ToString() method to return the polygon data as text. Example output: POLYGON ((-6.1646509904325884 56.435153006374627, ... -6.1606079906751 56.4338050060666)) MULTIPOLYGON (((-6.1646509904325884 56.435153006374627 0 0, ... -6.1606079906751 56.4338050060666 0 0))) Geographic definitions can take the form of either an array of lat/long pairs defining a polygon or in the case of multiple definitions, an array or polygons (multipolygon). I have the following regex that converts the output to JSON objects contained in multi-dimensional arrays depending on the output. Regex latlngMatch = new Regex(@"(-?[0-9]{1}\.\d*)\s(\d{2}.\d*)(?:\s0\s0,?)?", RegexOptions.Compiled); private string ConvertPolysToJson(string polysIn) { return this.latlngMatch.Replace(polysIn.Remove(0, polysIn.IndexOf("(")) // remove POLYGON or MULTIPOLYGON .Replace("(", "[") // convert to JSON array syntax .Replace(")", "]"), // same as above "{lng:$1,lat:$2},"); // reformat lat/lng pairs to JSON objects } This is actually working pretty well and converts the DB output to JSON on the fly in response to an operation call. However I am no regex master and the calls to String.Replace() also seem inefficient to me. Does anyone have any suggestions/comments about performance of this?

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