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  • What's the best way to communicate the purpose of a string parameter in a public API?

    - by Dave
    According to the guidance published in New Recommendations for Using Strings in Microsoft .NET 2.0, the data in a string may exhibit one of the following types of behavior: A non-linguistic identifier, where bytes match exactly. A non-linguistic identifier, where case is irrelevant, especially a piece of data stored in most Microsoft Windows system services. Culturally-agnostic data, which still is linguistically relevant. Data that requires local linguistic customs. Given that, I'd like to know the best way to communicate which behavior is expected of a string parameter in a public API. I wasn't able to find an answer in the Framework Design Guidelines. Consider the following methods: f(string this_is_a_linguistic_string) g(string this_is_a_symbolic_identifier_so_use_ordinal_compares) Is variable naming and XML documentation the best I can do? Could I use attributes in some way to mark the requirements of the string? Now consider the following case: h(Dictionary<string, object> dictionary) Note that the dictionary instance is created by the caller. How do I communicate that the callee expects the IEqualityComparer<string> object held by the dictionary to perform, for example, a case-insensitive ordinal comparison?

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  • WP7 - Cancelling ContextMenu click event propagation

    - by Praetorian
    I'm having a problem when the Silverlight toolkit's ContextMenu is clicked while it is over a UIElement that has registered a Tap event GestureListener. The context menu click propagates to the underlying element and fires its tap event. For instance, say I have a ListBox and each ListBoxItem within it has registered both a ContextMenu and a Tap GestureListener. Assume that clicking context menu item2 is supposed to take you to Page1.xaml, while tapping on any of ListBox items themselves is supposed to take you to Page2.xaml. If I open the context menu on item1 in the ListBox, then context menu item2 is on top of ListBox item2. When I click on context menu item2 I get weird behavior where the app navigates to Page1.xaml and then immediately to Page2.xaml because the click event also triggered the Tap gesture for ListBox item2. I've verified in the debugger that it is always the context menu that receives the click event first. How do I cancel the context menu item click's routed event propagation so it doesn't reach ListBox item2? Thanks for your help!

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  • Is is possible to do an end-run around generics covariance in C# < 4 in this hypothetical situation?

    - by John Feminella
    Suppose I have a small inheritance hierarchy of Animals: public interface IAnimal { string Speak(); } public class Animal : IAnimal { public Animal() {} public string Speak() { return "[Animal] Growl!"; } } public class Ape : IAnimal { public string Speak() { return "[Ape] Rawrrrrrrr!"; } } public class Bat : IAnimal { public string Speak() { return "[Bat] Screeeeeee!"; } } Next, here's an interface offering a way to turn strings into IAnimals. public interface ITransmogrifier<T> where T : IAnimal { T Transmogrify(string s); } And finally, here's one strategy for doing that: public class Transmogrifier<T> : ITransmogrifier<T> where T : IAnimal, new() { public T Transmogrify(string s) { T t = default(T); if (typeof(T).Name == s) t = new T(); return t; } } Now, the question. Is it possible to replace the sections marked [1], [2], and [3] such that this program will compile and run correctly? If you can't do it without touching parts other than [1], [2], and [3], can you still get an IAnimal out of each instance of a Transmogrifier in a collection containing arbitrary implementations of an IAnimal? Can you even form such a collection to begin with? static void Main(string[] args) { var t = new Transmogrifier<Ape>(); Ape a = t.Transmogrify("Ape"); Console.WriteLine(a.Speak()); // Works! // But can we make an arbitrary collection of such animals? var list = new List<Transmogrifier< [1] >>() { // [2] }; // And how about we call Transmogrify() on each one? foreach (/* [3] */ transmogrifier in list) { IAnimal ia = transmogrifier.Transmogrify("Bat"); } } }

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  • which is better: a lying copy constructor or a non-standard one?

    - by PaulH
    I have a C++ class that contains a non-copyable handle. The class, however, must have a copy constructor. So, I've implemented one that transfers ownership of the handle to the new object (as below) class Foo { public: Foo() : h_( INVALID_HANDLE_VALUE ) { }; // transfer the handle to the new instance Foo( const Foo& other ) : h_( other.Detach() ) { }; ~Foo() { if( INVALID_HANDLE_VALUE != h_ ) CloseHandle( h_ ); }; // other interesting functions... private: /// disallow assignment const Foo& operator=( const Foo& ); HANDLE Detach() const { HANDLE h = h_; h_ = INVALID_HANDLE_VALUE; return h; }; /// a non-copyable handle mutable HANDLE h_; }; // class Foo My problem is that the standard copy constructor takes a const-reference and I'm modifying that reference. So, I'd like to know which is better (and why): a non-standard copy constructor: Foo( Foo& other ); a copy-constructor that 'lies': Foo( const Foo& other ); Thanks, PaulH

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  • Returning a reference from a Class member?

    - by nebukadnezzar
    Hi, I've a class that basically looks like this: class App { public function newTemplate($filename, $vars=array()) { $smarty = new Smarty; $smarty->compile_dir = $this->template_compile_path; if(count($vars) > 0) { foreach($vars as $v_key => $v_name) { $smarty->assign($v_key, $v_name); } } return $smarty; } } However, when I create a Instance of 'App', the reference to $smarty seems broken, as every call to the membermethods don't seem to do anything: $app = new App; $tpl = $app->newTemplate("index.tmpl"); $tpl->assign("foo", "bar"); // {$foo} does not appear with "bar" in the template Now I wonder why? Of course I tried to use references: ... public function &newTemplate() ... ... But that doesn't work. Variable references don't seem to work either: ... $tpl = &$app->newTemplate("index.tmpl"); ... What is causing PHP here not to return a proper reference? Help is very appreciated!

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  • Catch a PHP Object Instantiation Error

    - by Rob Wilkerson
    It's really irking me that PHP considers the failure to instantiate an object a Fatal Error (which can't be caught) for the application as a whole. I have set of classes that aren't strictly necessary for my application to function--they're really a convenience. I have a factory object that attempts to instantiate the class variant that's indicated in a config file. This mechanism is being deployed for message storage and will support multiple store types: DatabaseMessageStore FileMessageStore MemcachedMessageStore etc. A MessageStoreFactory class will read the application's preference from a config file, instantiate and return an instance of the appropriate class. It might be easy enough to slap a conditional around the instantiation to ensure that class_exists(), but MemcachedMessageStore extends PHP's Memcached class. As a result, the class_exists() test will succeed--though instantiation will fail--if the memcached bindings for PHP aren't installed. Is there any other way to test whether a class can be instantiated properly? If it can't, all I need to do is tell the user which features won't be available to them, but let them continue one with the application. Thanks.

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  • How to make Spring load a JDBC Driver BEFORE initializing Hibernate's SessionFactory?

    - by Bill_BsB
    I'm developing a Spring(2.5.6)+Hibernate(3.2.6) web application to connect to a custom database. For that I have custom JDBC Driver and Hibernate Dialect. I know for sure that these custom classes work (hard coded stuff on my unit tests). The problem, I guess, is with the order on which things get loaded by Spring. Basically: Custom Database initializes Spring load beans from web.xml Spring loads ServletBeans(applicationContext.xml) Hibernate kicks in: shows version and all the properties correctly loaded. Hibernate's HbmBinder runs (maps all my classes) LocalSessionFactoryBean - Building new Hibernate SessionFactory DriverManagerConnectionProvider - using driver: MyCustomJDBCDriver at CustomDBURL I get a SQLException: No suitable driver found for CustomDBURL Hibernate loads the Custom Dialect My CustomJDBCDriver finally gets registered with DriverManager (log messages) SettingsFactory runs SchemaExport runs (hbm2ddl) I get a SQLException: No suitable driver found for CustomDBURL (again?!) Application get successfully deployed but there are no tables on my custom Database. Things that I tried so far: Different techniques for passing hibernate properties: embedded in the 'sessionFactory' bean, loaded from a hibernate.properties file. Nothing worked but I didn't try with hibernate.cfg.xml file neither with a dataSource bean yet. MyCustomJDBCDriver has a static initializer block that registers it self with the DriverManager. Tried different combinations of lazy initializing (lazy-init="true") of the Spring beans but nothing worked. My custom JDBC driver should be the first thing to be loaded - not sure if by Spring but...! Can anyone give me a solution for this or maybe a hint for what else I could try? I can provide more details (huge stack traces for instance) if that helps. Thanks in advance.

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  • linux bash script: set date/time variable to auto-update (for inclusion in file names)

    - by user1859492
    Essentially, I have a standard format for file naming conventions. It breaks down to this: target_dateUTC_timeUTC_tool So, for instance, if I run tcpdump on a target of 'foo', then the file would be foo_dateUTC_timeUTC_tcpdump. Simple enough, but a pain for everyone to constantly (and consistently) enter... so I've tried to create a bash script which sets system variables like so: FILENAME=$TARGET\_$UTCTIME\_$TOOL Then, I can just call the variable at runtime, like so: tcpdump -w $FILENAME.lpc All of this works like a champ. I've got a menu-driven .sh which gives the user the options of viewing the current variables as well as setting them... file generation is a breeze. Unfortunately, by setting the date/time variable, it is locked to the value at the time of creation (naturally). I set the variable like so: UTCTIME=$(/bin/date --utc +"%Y%m%d_%H%M%Z") What I really need is either a way to create a variable which updates at runtime, or (more likely) another way to skin this cat. While scouring for solutions, I came across a similar issues... like this. But, to be honest, I'm stumped on how to marry the two approaches and create a simple, distributable solution. I can post the entire .sh if anyone cares to review (about 120 lines)

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  • how to bind a list to a dropdown list in gridview

    - by user3721173
    I have a GridView that it contain a Drop-down list.I have a list that wanna to bind this list to drop-down in gridview. <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"OnSelectedIndexChanged="GridView1_SelectedIndexChanged" OnRowDataBound="GridView1_RowDataBound"> <Columns> <ItemTemplate> <asp:Label ID="Label2" runat="server"></asp:Label> <asp:DropDownList ID="DropDownList3" runat="server" AppendDataBoundItems="True" OnSelectedIndexChanged="DropDownList3_SelectedIndexChanged1" > </asp:DropDownList> </ItemTemplate> </asp:TemplateField> </Columns> and protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e) { DropDownList dropdown = (DropDownList)e.Row.FindControl("DropDownList3"); ClassDal obj = new ClassDal(); List<phone> list = obj.GetAll(); dropdown.DataTextField = "phone"; dropdown.DataValueField = "id"; dropdown.DataSource = list.ToList(); dropdown.DataBind(); } and namespace sample_table { public class ClassDal { public List<phone> GetAll() { using (PracticeDBEntities1 context = new PracticeDBEntities1()) { return context.phone.ToList(); } } } } but i received this exception :Object reference not set to an instance of an object on the row: dropdown.DataTextField = "phone";

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  • Pattern for version-specific implementations of a Java class

    - by Mike Monkiewicz
    So here's my conundrum. I am programming a tool that needs to work on old versions of our application. I have the code to the application, but can not alter any of the classes. To pull information out of our database, I have a DTO of sorts that is populated by Hibernate. It consumes a data object for version 1.0 of our app, cleverly named DataObject. Below is the DTO class. public class MyDTO { private MyWrapperClass wrapper; public MyDTO(DataObject data) { wrapper = new MyWrapperClass(data); } } The DTO is instantiated through a Hibernate query as follows: select new com.foo.bar.MyDTO(t1.data) from mytable t1 Now, a little logic is needed on top of the data object, so I made a wrapper class for it. Note the DTO stores an instance of the wrapper class, not the original data object. public class MyWrapperClass { private DataObject data; public MyWrapperClass(DataObject data) { this.data = data; } public String doSomethingImportant() { ... version-specific logic ... } } This works well until I need to work on version 2.0 of our application. Now DataObject in the two versions are very similar, but not the same. This resulted in different sub classes of MyWrapperClass, which implement their own version-specific doSomethingImportant(). Still doing okay. But how does myDTO instantiate the appropriate version-specific MyWrapperClass? Hibernate is in turn instantiating MyDTO, so it's not like I can @Autowire a dependency in Spring. I would love to reuse MyDTO (and my dozens of other DTOs) for both versions of the tool, without having to duplicate the class. Don't repeat yourself, and all that. I'm sure there's a very simple pattern I'm missing that would help this. Any suggestions?

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  • Ftp throws WebException only in .NET 4.0

    - by Trakhan
    I have following c# code. It runs just fine when compiled against .NET framework 3.5 or 2.0 (I did not test it against 3.0, but it will most likely work too). The problem is, that it fails when built against .NET framework 4.0. FtpWebRequest Ftp = (FtpWebRequest)FtpWebRequest.Create(Url_ + '/' + e.Name); Ftp.Method = WebRequestMethods.Ftp.UploadFile; Ftp.Credentials = new NetworkCredential(Login_, Password_); Ftp.UseBinary = true; Ftp.KeepAlive = false; Ftp.UsePassive = true; Stream S = Ftp.GetRequestStream(); byte[] Content = null; bool Continue = false; do { try { Continue = false; Content = File.ReadAllBytes(e.FullPath); } catch (Exception) { Continue = true; System.Threading.Thread.Sleep(500); } } while (Continue); S.Write(Content, 0, Content.Length); S.Close(); FtpWebResponse Resp = (FtpWebResponse)Ftp.GetResponse(); if (Resp.StatusCode != FtpStatusCode.CommandOK) Console.WriteLine(Resp.StatusDescription); The problem is in call Stream S = Ftp.GetRequestStream();, which throws an en instance of WebException with message “The remote server returned an error: (500) Syntax error, command unrecognized”. Does anybody know why it is so? PS. I communicate virtual ftp server in ECM Alfresco.

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  • "Detecting" and loading of "plugins" in GAE

    - by Patrick Cornelissen
    Hi! I have a "plugin like" architecture and I want to create one instance of each class that implements a dedicated interface and put these in a cache. (To have a singleton-ish effect). The plugins will be provided as jars and put into the app engine war file before the app is uploaded. I have tried to use the ClassPathScanningCandidateComponentProvider as I'm using spring anyway, but this didn't work. The provider complained that it was not able to find the HttpServletResponse class file while scanning the classpath. I can't get around this, when I add the servlet jar, then I'll get of course problems, because the same jar is also provided by the GAE. If I don't, I'm getting the error above... So I tried to add a static initialization code, but of course this doesn't work, because the class is initialized when it's instantiated for the first time. (Well I knew that but it was worth a try) The last chance I currently see is that I create a properties file with all plugin classes when the package is created, but this requires writing of a maven plugin etc. and I'd like to avoid that. Is there something that I am missing?

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  • Adding li element only if it not already there?

    - by Legend
    I am constructing an <li> element like this: var element = $("<li></li>") .html(mHTML) .attr('id', "elemid"); I am trying to add this element to a <ul> element only if it doesn't already exist. Any ideas on how to do this? Am I supposed to use contains() to see if the ul element contain the html and then decide? For instance, <ul id="elemul"> <li id="elemli1">Element 1</li> <li id="elemli2">Element 2</li> <li id="elemli3">Element 3</li> </ul> If I try adding Element 1, it should not add it. What should I do if its a longer string (not really long but about 150 characters). Note: I cannot rely on IDs to determine the uniqueness. i.e. I might end up forming something like: <li id="elemli3">Element 1</li> Do I go about using hashmaps?

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  • Random number generation in MVC applications

    - by SlimShaggy
    What is the correct way of generating random numbers in an ASP.NET MVC application if I need exactly one number per request? According to MSDN, in order to get randomness of sufficient quality, it is necessary to generate multiple numbers using a single System.Random object, created once. Since a new instance of a controller class is created for each request in MVC, I cannot use a private field initialized in the controller's constructor for the Random object. So in what part of the MVC app should I create and store the Random object? Currently I store it in a static field of the controller class and lazily initialize it in the action method that uses it: public class HomeController : Controller { ... private static Random random; ... public ActionResult Download() { ... if (random == null) random = new Random(); ... } } Since the "random" field can be accessed by multiple instances of the controller class, is it possible for its value to become corrupted if two instances attempt to initialize it simultaneously? And one more question: I know that the lifetime of statics is the lifetime of the application, but in case of an MVC app what is it? Is it from IIS startup till IIS shutdown?

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  • Java reflection appropriateness

    - by jsn
    This may be a fairly subjective question, but maybe not. My application contains a bunch of forms that are displayed to the user at different times. Each form is a class of its own. Typically the user clicks a button, which launches a new form. I have a convenience function that builds these buttons, you call it like this: buildButton( "button text", new SelectionAdapter() { @Override public void widgetSelected( SelectionEvent e ) { showForm( new TasksForm( args... ) ); } } ); I do this dozens of times, and it's really cumbersome having to make a SelectionAdapter every time. Really all I need for the button to know is what class to instantiate when it's clicked and what arguments to give the constructor, so I built a function that I call like this instead: buildButton( "button text", TasksForm.class, args... ); Where args is an arbitrary list of objects that you could use to instantiate TasksForm normally. It uses reflection to get a constructor from the class, match the argument list, and build an instance when it needs to. Most of the time I don't have to pass any arguments to the constructor at all. The downside is obviously that if I'm passing a bad set of arguments, it can't detect that at compilation time, so if it fails, a dialog is displayed at runtime. But it won't normally fail, and it'll be easy to debug if it does. I think this is much cleaner because I come from languages where the use of function and class literals is pretty common. But if you're a normal Java programmer, would seeing this freak you out, or would you appreciate not having to scan a zillion SelectionAdapters?

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  • Robotlegs: Warning: Injector already has a rule for type

    - by MikeW
    I have a bunch of warning messages like this appear when using Robotlegs/Signals. Everytime this command class executes, which is every 2-3 seconds ..this message displays below If you have overwritten this mapping intentionally you can use "injector.unmap()" prior to your replacement mapping in order to avoid seeing this message. Warning: Injector already has a rule for type "mx.messaging.messages::IMessage", named "". The command functions fine otherwise but I think I'm doing something wrong anyhow. public class MessageReceivedCommand extends SignalCommand { [Inject] public var message:IMessage; ...etc.. do something with message.. } the application context doesnt map IMessage to this command, as I only see an option to mapSignalClass , besides the payload is received fine. Wonder if anyone knows how I might either fix or suppress this message. I've tried calling this as the warning suggests injector.unmap(IMessage, "") but I receive an error - no mapping found for ::IMessage named "". Thanks Edit: A bit more info about the error Here is the signal that I dispatch to the command public class GameMessageSignal extends Signal { public function GameMessageSignal() { super(IMessage); } } which is dispatched from a IPushDataService class gameMessage.dispatch(message.message); and the implementation is wired up in the app context via injector.mapClass(IPushDataService, PushDataService); along with the signal signalCommandMap.mapSignalClass(GameMessageSignal, MessageReceivedCommand); Edit #2: Probably good to point out also I inject an instance of GameMessageSignal into IPushDataService public class PushDataService extends BaseDataService implements IPushDataService { [Inject] public var gameMessage:GameMessageSignal; //then private function processMessage(message:MessageEvent):void { gameMessage.dispatch(message.message); } } Edit:3 The mappings i set up in the SignalContext: injector.mapSingleton(IPushDataService); injector.mapClass(IPushDataService, PushDataService);

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  • select nodes from a line of xml code with sql

    - by wondergoat77
    I have a table that stores a huge line/entire document of xml like this: <?xml version="1.0" encoding="utf-16"?> <RealQuestResponse xmlns:xsi="http://www.w3.org /2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Success>true</Success> <Subject> <AmbiguousMatches /> <Assessment> <LandValue>0</LandValue> <ImprovementsValue>0</ImprovementsValue> <TotalValue>0</TotalValue> </Assessment> <RecentSales /> <Warnings> <Score>0</Score> <TrusteesDeedRatio>0</Tr........etc Is there a way to pull any of these fields out of the xml? it is stored in a column in a table called AutomatedRequests That table looks like this: requestid Provider Date Success Response 1 test 1/2/2012 Y <?xml version..... <---this is the xml code stored> Ive seen a couple ways but nothing like this Id basically like something like select xmlnode1, xmlnode2, xmlnode3 from automatedrequests have tried this but not working: select xml.query('RealQuestResponse/Bedrooms/*') from automatedRequests where orderid = 1266162

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  • How to call a generic method with an anonymous type involving generics?

    - by Alex Black
    I've got this code that works: def testTypeSpecialization = { class Foo[T] def add[T](obj: Foo[T]): Foo[T] = obj def addInt[X <% Foo[Int]](obj: X): X = { add(obj) obj } val foo = addInt(new Foo[Int] { def someMethod: String = "Hello world" }) assert(true) } But, I'd like to write it like this: def testTypeSpecialization = { class Foo[T] def add[X, T <% Foo[X](obj: T): T = obj val foo = add(new Foo[Int] { def someMethod: String = "Hello world" }) assert(true) } This second one fails to compile: no implicit argument matching parameter type (Foo[Int]{ ... }) = Foo[Nothing] was found. Basically: I'd like to create a new anonymous class/instance on the fly (e.g. new Foo[Int] { ... } ), and pass it into an "add" method which will add it to a list, and then return it The key thing here is that the variable from "val foo = " I'd like its type to be the anonymous class, not Foo[Int], since it adds methods (someMethod in this example) Any ideas? I think the 2nd one fails because the type Int is being erased. I can apparently 'hint' the compiler like this: def testTypeSpecialization = { class Foo[T] def add[X, T <% Foo[X]](dummy: X, obj: T): T = obj val foo = add(2, new Foo[Int] { def someMethod: String = "Hello world" }) assert(true) }

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  • objective-c having issues with an NSDictioary object

    - by Mark
    I have a simple iPhone app that Im learning and I want to have an instance variable called urlLists which is an NSDictionary I have declared it like so: @interface MyViewController : UIViewController <UIPickerViewDataSource, UIPickerViewDelegate>{ IBOutlet UIPickerView *pickerView; NSMutableArray *categories; NSDictionary *urlLists; } @property(retain) NSDictionary *urlLists; @end and in the implementation: @implementation MyViewController @synthesize urlLists; ... - (void)viewDidLoad { [super viewDidLoad]; categories = [[NSMutableArray alloc] init]; [categories addObject:@"Sport"]; [categories addObject:@"Entertainment"]; [categories addObject:@"Technology"]; [categories addObject:@"Political"]; NSArray *objects = [NSArray arrayWithObjects:@"value1", @"value2", @"value3", @"value4", nil]; urlLists = [NSDictionary dictionaryWithObjects:objects forKeys:categories]; for (id key in urlLists) { NSLog(@"key: %@, value: %@", key, [urlLists objectForKey:key]); } } ... @end And, this all works up to here. I have added a UIPicker to my app, and when I select one of the items, I want to Log the one picked and its related entry in my dictionary. -(void) pickerView:(UIPickerView *)thePickerView didSelectRow:(NSInteger)row inComponent:(NSInteger) component { for (id key in self.urlLists) { NSLog(@"key: %@, value: %@", key, [urlLists objectForKey:key]); } } but I get the old EXC_BAD_ACCESS error... I know Im missing something small, but what? Thanks

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  • Blocking HTML and Javascript from being displayed on my site

    - by Tim Powell
    I am working on this new social networking site. One of it's various functions is posting. You can post to Facebook and my site, or Twitter and my site. That being said, I couldn't help but try and post HTML as I was testing sql injection. When I did, I noticed that there where ways to manipulate the site to, for instance, using a element to completely screw up the CSS design, or redirect a user to another site using javascript. That being said, I want to make my site a safe environment for my users... not a site that is used to distribute computer viruses, porn, and other things that might make someone tend to stay off of my site. When I searched this topic, I found ways to "strip" the HTML out of the $post variable before submitting it to the database. However, I would just like to make it so you can post any text, including HTML and Javascript, without the browser interpreting it as "run this..." code: I want to display it as plane text. I've seen it on Facebook, and when I looked at it the source code of a post, it showed <, /, and as regular text. I tried "dissecting" Facebook's source code, but found nothing. I have tried using tags such as <pre> and <code>, but because of the lack of ability to style and control them, I gave up and went back to just allowing HTML. Please, anyone who knows how to do this, please help me out. Thanks in advance, TP

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  • transaction handling in dataset based insert/update in c#

    - by user3703611
    I am trying to insert bulk records in a sql server database table using dataset. But i am unable to do transaction handling. Please help me to apply transaction handling in below code. I am using adapter.UpdateCommand.Transaction = trans; but this line give me an error of Object reference not set to an instance of an object. Code: string ConnectionString = "server=localhost\\sqlexpress;database=WindowsApp;Integrated Security=SSPI;"; SqlConnection conn = new SqlConnection(ConnectionString); conn.Open(); SqlTransaction trans = conn.BeginTransaction(IsolationLevel.Serializable); SqlDataAdapter adapter = new SqlDataAdapter("SELECT * FROM Test ORDER BY Id", conn); SqlCommandBuilder builder = new SqlCommandBuilder(adapter); adapter.UpdateCommand.Transaction = trans; // Create a dataset object DataSet ds = new DataSet("TestSet"); adapter.Fill(ds, "Test"); // Create a data table object and add a new row DataTable TestTable = ds.Tables["Test"]; for (int i=1;i<=50;i++) { DataRow row = TestTable.NewRow(); row["Id"] = i; TestTable .Rows.Add(row); } // Update data adapter adapter.Update(ds, "Test"); trans.Commit(); conn.Close();

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  • Proper structure for dependency injection (using Guice)

    - by David B.
    I would like some suggestions and feedback on the best way to structure dependency injection for a system with the structure described below. I'm using Guice and thus would prefer solutions centered around it's annotation-based declarations, not XML-heavy Spring-style configuration. Consider a set of similar objects, Ball, Box, and Tube, each dependent on a Logger, supplied via the constructor. (This might not be important, but all four classes happen to be singletons --- of the application, not Gang-of-Four, variety.) A ToyChest class is responsible for creating and managing the three shape objects. ToyChest itself is not dependent on Logger, aside from creating the shape objects which are. The ToyChest class is instantiated as an application singleton in a Main class. I'm confused about the best way to construct the shapes in ToyChest. I either (1) need access to a Guice Injector instance already attached to a Module binding Logger to an implementation or (2) need to create a new Injector attached to the right Module. (1) is accomplished by adding an @Inject Injector injectorfield to ToyChest, but this feels weird because ToyChest doesn't actually have any direct dependencies --- only those of the children it instantiates. For (2), I'm not sure how to pass in the appropriate Module. Am I on the right track? Is there a better way to structure this? The answers to this question mention passing in a Provider instead of using the Injector directly, but I'm not sure how that is supposed to work. EDIT: Perhaps a more simple question is: when using Guice, where is the proper place to construct the shapes objects? ToyChest will do some configuration with them, but I suppose they could be constructed elsewhere. ToyChest (as the container managing them), and not Main, just seems to me like the appropriate place to construct them.

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  • Best way to organize a Go interface

    - by Metropolis
    Hey Everyone, Its been a long time since I have programmed in C++, and if I remember correctly the best way to organize classes was to create your class in the .h file, and then your implementation in your .cpp file. Well I am trying to learn Go now and I was reading over the Go for C++ Programmers article when I came upon interfaces. The article explains that interfaces in Go essentially take the place of classes, and shows how to set them up pretty well. What I am trying to figure out though is how should I organize an interface into files? For instance, should the interface be in one file while the implementation is in another? myInterface.go type myInterface interface { get() int set(i int) } myImplementation.go type myType struct { i int } func (p *myType) set(i int) { p.i = i } func (p *myType) get() int { return p.i } My code here may be wrong since I do not completely know what I am doing yet (and if I am wrong please correct me), but would this be the best way to set this up? Im having a very hard time trying to wrap my head around how to organize code in Go so any help is appreciated! Metropolis

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  • Building argv and argc

    - by Wylie Coyote SG.
    I'm a student programmer using Qt to build a GUI application for work. The primary purpose of this application is to open some of our old style files, allows better editing and then save the file in a new format and file extension. Recently I have been asked to allow this conversion to take place from a terminal. While I do know what argv and argc are along with what they represent I am unsure how to accomplish what they want. For instance how to handle relative paths vs. absolute... maybe how to get absolute from relative; perhaps none of that is even needed. My programming experience has been primarily with guis so this is a little new to me. Users would like the following to be ran from the terminal application -o /fileLocation /fileDestination template(to determine new format) I began to use for loops and if statements to begin accomplishing this when I relized that I might be taking the worng approach to all of this. I WOULD ALSO BE REALLY INTERESTED IF QT HAS SOMETHING FOR THIS! Here is what I have began coming up with: int main(int argc, char *argv[]) { if(argc > 1) { for(int i = 0; i < argc; i++) { if(argv[i] == "-c") { QString fileName = QString::fromStdString(argv[i+1]); QString fileDestination = QString::fromStdString(argv[i+2]); QString templateName = QString::fromStdString(argv[i+3]); QFile fileToConvert(fileName); if(fileToConvert.open(QFile::ReadOnly)) { //do stuff Thanks for reading my post and a big thanks for any contributions you make to helping me overcome this issue.

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  • Simulate stochastic bipartite network based on trait values of species - in R

    - by Scott Chamberlain
    I would like to create bipartite networks in R. For example, if you have a data.frame of two types of species (that can only interact across species, not within species), and each species has a trait value (e.g., size of mouth in the predator allows who gets to eat which prey species), how do we simulate a network based on the traits of the species (that is, two species can only interact if their traits overlap in values for instance)? UPDATE: Here is a minimal example of what I am trying to do. 1) create phylogenetic tree; 2) simulate traits on the phylogeny; 3) create networks based on species trait values. # packages install.packages(c("ape","phytools")) library(ape); library(phytools) # Make phylogenetic trees tree_predator <- rcoal(10) tree_prey <- rcoal(10) # Simulate traits on each tree trait_predator <- fastBM(tree_predator) trait_prey <- fastBM(tree_prey) # Create network of predator and prey ## This is the part I can't do yet. I want to create bipartite networks, where ## predator and prey interact based on certain crriteria. For example, predator ## species A and prey species B only interact if their body size ratio is ## greater than X.

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