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  • Accessing Application Scoped Bean Causes NullPointerException

    - by user2946861
    What is an Application Scoped Bean? I understand it to be a bean which will exist for the life of the application, but that doesn't appear to be the correct interpretation. I have an application which creates an application scoped bean on startup (eager=true) and then a session bean that tries to access the application scoped bean's objects (which are also application scoped). But when I try to access the application scoped bean from the session scoped bean, I get a null pointer exception. Here's excerpts from my code: Application Scoped Bean: @ManagedBean(eager=true) @ApplicationScoped public class Bean1 implements Serializable{ private static final long serialVersionUID = 12345L; protected ArrayList<App> apps; // construct apps so they are available for the session scoped bean // do time consuming stuff... // getters + setters Session Scoped Bean: @ManagedBean @SessionScoped public class Bean2 implements Serializable{ private static final long serialVersionUID = 123L; @Inject private Bean1 bean1; private ArrayList<App> apps = bean1.getApps(); // null pointer exception What appears to be happening is, Bean1 is created, does it's stuff, then is destroyed before Bean2 can access it. I was hoping using application scoped would keep Bean1 around until the container was shutdown, or the application was killed, but this doesn't appear to be the case.

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  • What should I name instances of a twisted.internet.defer.Deferred?

    - by slacy
    I'm writing code using Twisted, and having trouble coming up with a sensible variable name for my twisted internet deferred's. Here are my candidates: d : Too generic, too short, violates pylint rule C0103. def : Conflicts with function defintion builtin. defer : Conflicts with module twisted.internet.defer deferred : OK but pretty long cb : Still too short, violates pylint C0103, conflicts with many callback method names. cback : Too Weird? callback : Conflicts with method Deferred.callback() I'm looking for other suggestions. It seems like most of the Twisted example code uses "d" which is fine for simple invocations, but when you're passing Deferred's around to methods and storing them as member variables, it's really far too descriptive.

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  • When to update audit fields? DDD

    - by user676767
    I have a Meeting Object: Meeting{id, name, time, CreatedBy, UpdatedBy} and a MeetingAssignee{id, MeetingID, EmployeeId, CreatedBy, UpdatedBy) Meeting, as Aggregate root, has a method AssignEmployee. I was about to pass in the current user to the Meeting object as I call AssignEmployee, so that it can update its audit fields accordingly. But this doesn't seem right - is it? Obviously I can keep the audit fields public and change them later - perhaps at service level? What is everyone's else preferred method for updating these fields? Please note: We are not using Nhibernate, but a custom ORM which does not have anything automatic in place. Thanks.

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  • Line breaks in XML are ignored by the SAX Parser

    - by Siddharth Iyer
    I am parsing an XML with some CData that contains line breaks. The parser ignores these line breaks. I am trying to figure out a way to catch these newlines in the characters() method and replace them with a break tag for display purposes. I have tried almost everything under the sun and have been scouring stackoverflow for the past 3 hours. I tried every combination of replacing "\n", "\r\n" and so on with a break tag in the characters() method of the parser. I am absolutely helpless right about now.... and would sincerely appreciate any help I can get. Thanks!!!

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  • Real-world examples of populating a GWT CellTable using a clean MVP pattern?

    - by piehole
    We are using the GWT-Presenter framework and attempting to use CellTable to put together an updateable grid. It seems as though several of the GWT constructs for CellTable don't lend themselves to easily breaking up the logic into clean view and presenter code. Examples: 1) Within the View's constructor, the CellTable is defined and each column is created by anonymous inner classes that extend the Column class to provide the onValue() method. 2) The FieldUpdater interface must be implemented to provide logic to execute when a user alters data in a cell. This seems like it would best fit in the Presenter's onBind() method, but FieldUpdaters often need access to the Cell or Column which belong in the view. CellTable does not have accessor methods to get hold of the Columns or Cells, so it seems the only way for the Presenter to get them is for me to create a multitude of member variables on the View and accessors on my Display interface. Can anyone provide good examples for dealing with CellTable in GWT-Presenter or a comparable MVP

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  • Forcing LINQ to SQL to make one single call for all child rows

    - by zaph0d
    Let say I have a method (example taken from another post): public IQueryable<CityBlock> GetCityBlocks(){ var results = from o in db.city_blocks let buildings = GetBuildingsOnBlock(o.block_id) //returns Iqueryable select new CityBlock { BuildingsOnBlock = buildings, BlockOwner = o.block_owner }; return results; } In the calling method I add Skip() and Take() methods plus some filtering and then do a ToList(). The trouble is that I am getting dozens of database calls - one for all the city blocks and then a separate one for each building. Is there a way that I can refactor this code to just make two calls: one for the city blocks and one for all the buildings

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  • Is this use of PreparedStatements in a Thread in JAVA correct?

    - by Gormcito
    I'm still an undergrad just working part time and so I'm always trying to be aware of better ways to do things. Recently I had to write a program for work where the main thread of the program would spawn "task" threads (for each db "task" record) which would perform some operations and then update the record to say that it has finished. Therefore I needed a database connection object and PreparedStatement objects in or available to the ThreadedTask objects. This is roughly what I ended up writing, is creating a PreparedStatement object per thread a waste? I thought static PreparedStatments could create race conditions... Thread A stmt.setInt(); Thread B stmt.setInt(); Thread A stmt.execute(); Thread B stmt.execute(); A´s version never gets execed.. Is this thread safe? Is creating and destroying PreparedStatement objects that are always the same not a huge waste? public class ThreadedTask implements runnable { private final PreparedStatement taskCompleteStmt; public ThreadedTask() { //... taskCompleteStmt = Main.db.prepareStatement(...); } public run() { //... taskCompleteStmt.executeUpdate(); } } public class Main { public static final db = DriverManager.getConnection(...); }

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  • C#: Passing data to forms UI using BeginInvoke

    - by Bi
    Hi I am a C# newbie and have a class that needs to pass row information to a grid in the windows form. What is the best way to do it? I have put in some example code for better understanding. Thanks. public class GUIController { private My_Main myWindow; public GUIController( My_Main window ) { myWindow = window; } public void UpdateProducts( List<myProduct> newList ) { object[] row = new object[3]; foreach (myProduct product in newList) { row[0] = product.Name; row[1] = product.Status; row[2] = product.Day; //HOW DO I USE BeginInvoke HERE? } } } And the form class below: public class My_Main : Form { //HOW DO I GO ABOUT USING THIS DELEGATE? public delegate void ProductDelegate( string[] row ); public static My_Main theWindow = null; static void Main( ) { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); theWindow = new My_Main(); Application.Run(theWindow); } private void My_Main_Load( object sender, EventArgs e ) { /// Create GUIController and pass the window object gui = new GUIController( this ); } public void PopulateGrid( string[] row ) { ProductsGrid.Rows.Add(row); ProductsGrid.Update(); } } Thanks!

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  • measuring a view before rendering it

    - by nourdine
    hello I need to find out how big a view will be after attaching it to its parent. I have overridden this method: onMeasure(int, int); but it looks like this method is invoked only when I actually add my custom view to it's container using: addView(myView); Do you think there is a way to get this information before rendering the view itself? Basically I need to know the actuall size before attaching it and not attach the view at all if it would take more certain amount of space. anybody?

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  • How decide whether a e-mail was newly sent, replied or forwarded?

    - by user572783
    I use Visual Studio 2010 to create an Outlook 2007 Addin. Now i want to know whether a e-mail was newly sent, replied or forwarded. Is there any property for this? using Outlook = Microsoft.Office.Interop.Outlook; namespace _Outlook2k7_Add_In { public partial class ThisAddIn { private void ThisAddIn_Startup(object sender, System.EventArgs e) { } private void ThisAddIn_Shutdown(object sender, System.EventArgs e) { } void Application_ItemSend(object Item, ref bool Cancel) { Outlook.MailItem mail = Item as Outlook.MailItem; if (mail == null) return; // Magic? } #region VSTO generated code /// <summary> /// Required method for Designer support - do not modify /// the contents of this method with the code editor. /// </summary> private void InternalStartup() { this.Startup += new System.EventHandler(ThisAddIn_Startup); this.Shutdown += new System.EventHandler(ThisAddIn_Shutdown); this.Application.ItemSend += new Outlook.ApplicationEvents_11_ItemSendEventHandler(Application_ItemSend); } #endregion } }

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  • Operator overloading in generic struct: can I create overloads for specific kinds(?) of generic?

    - by Carson Myers
    I'm defining physical units in C#, using generic structs, and it was going okay until I got the error: One of the parameters of a binary operator must be the containing type when trying to overload the mathematical operators so that they convert between different units. So, I have something like this: public interface ScalarUnit { } public class Duration : ScalarUnit { } public struct Scalar<T> where T : ScalarUnit { public readonly double Value; public Scalar(double Value) { this.Value = Value; } public static implicit operator double(Scalar<T> Value) { return Value.Value; } } public interface VectorUnit { } public class Displacement : VectorUnit { } public class Velocity : VectorUnit { } public struct Vector<T> where T : VectorUnit { #... public static Vector<Velocity> operator /(Vector<Displacement> v1, Scalar<Duration> v2) { return new Vector<Velocity>(v1.Magnitude / v2, v1.Direction); } } There aren't any errors for the + and - operators, where I'm just working on a Vector<T>, but when I substitute a unit for T, suddenly it doesn't like it. Is there a way to make this work? I figured it would work, since Displacement implements the VectorUnit interface, and I have where T : VectorUnit in the struct header. Am I at least on the right track here? I'm new to C# so I have difficulty understanding what's going on sometimes.

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  • How to yield a single element from for loop in scala?

    - by Julio Faerman
    Much like this question: Functional code for looping with early exit Say the code is def findFirst[T](objects: List[T]):T = { for (obj <- objects) { if (expensiveFunc(obj) != null) return /*???*/ Some(obj) } None } How to yield a single element from a for loop like this in scala? I do not want to use find, as proposed in the original question, i am curious about if and how it could be implemented using the for loop. * UPDATE * First, thanks for all the comments, but i guess i was not clear in the question. I am shooting for something like this: val seven = for { x <- 1 to 10 if x == 7 } return x And that does not compile. The two errors are: - return outside method definition - method main has return statement; needs result type I know find() would be better in this case, i am just learning and exploring the language. And in a more complex case with several iterators, i think finding with for can actually be usefull. Thanks commenters, i'll start a bounty to make up for the bad posing of the question :)

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  • Saving associated domain classes in Grails

    - by Cesar
    I'm struggling to get association right on Grails. Let's say I have two domain classes: class Engine { String name int numberOfCylinders = 4 static constraints = { name(blank:false, nullable:false) numberOfCylinders(range:4..8) } } class Car { int year String brand Engine engine = new Engine(name:"Default Engine") static constraints = { engine(nullable:false) brand(blank:false, nullable:false) year(nullable:false) } } The idea is that users can create cars without creating an engine first, and those cars get a default engine. In the CarController I have: def save = { def car = new Car(params) if(!car.hasErrors() && car.save()){ flash.message = "Car saved" redirect(action:index) }else{ render(view:'create', model:[car:car]) } } When trying to save, I get a null value exception on the Car.engine field, so obviously the default engine is not created and saved. I tried to manually create the engine: def save = { def car = new Car(params) car.engine = new Engine(name: "Default Engine") if(!car.hasErrors() && car.save()){ flash.message = "Car saved" redirect(action:index) }else{ render(view:'create', model:[car:car]) } } Didn't work either. Is Grails not able to save associated classes? How could I implement such feature?

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  • Absolutely positioned element moved by margin of another element

    - by user1505528
    Here is my jsFiddle for the following question: http://jsfiddle.net/arelia/Rruxf/ I'd like to have a header that stays at the very top of the body and a footer that stays at the very bottom of the body. I have a content div (position: relative) between the header and footer, and when I set a margin around the div my absolutely positioned header and footer move from their top/bottom positions by the height of that margin (this also happened when I tried setting a margin above and below the paragraphs in the div). In the fiddle you can see that the footer is not attached to the bottom even though it's absolutely positioned (I went ahead and made the header static since static gives the intended result). How do I position the header and footer to the top and bottom of the body and not have the content in the middle move those two elements? If the position: absolute elements are moved out of the flow why would anything affect their position at all? I've tried searching here and Google for "CSS margin affects absolute" and a few other phrases to no avail. I discovered this while playing around with it some more in developer tools: Metrics show the body is the height of the html element minus the amount of one margin (the margin that's still affecting the footer). So, the body must be stretching to the height of the content div since there is nothing else within the document flow within the body to define its height. But that height ends where the content ends instead of after the margin. Shouldn't it include the margin? If I make the height of the body 100%, the footer positions itself to the bottom of the viewport and then stays fixed in that spot when I scroll. Why isn't it attaching itself to the bottom of the body instead of the bottom of the viewport?

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  • In QT 4.6 w/ Webkit: How to handle popup window requests (WebView::createWindow)?

    - by CM
    Hi all, I'm new to QT and have been trying to create a test browser. What I'm trying to do now is to handle js-based popup requests. After reading the QT documentation, I learned that I need to re-implement the QWebView::createWindow method to do just that. Now I've re-implemented this method, but it seems to be not called when I try to click a link that triggers a popup window. Can any one help me? Do I need to subclass both the WebView and WebPage classes? If so, how do I do that? I'm quite new to QT and I've done tons of searches and found nothing. Thank you all in advance for any hint and advice!

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  • Java iterative vs recursive

    - by user1389813
    Can anyone explain why the following recursive method is faster than the iterative one (Both are doing it string concatenation) ? Isn't the iterative approach suppose to beat up the recursive one ? plus each recursive call adds a new layer on top of the stack which can be very space inefficient. private static void string_concat(StringBuilder sb, int count){ if(count >= 9999) return; string_concat(sb.append(count), count+1); } public static void main(String [] arg){ long s = System.currentTimeMillis(); StringBuilder sb = new StringBuilder(); for(int i = 0; i < 9999; i++){ sb.append(i); } System.out.println(System.currentTimeMillis()-s); s = System.currentTimeMillis(); string_concat(new StringBuilder(),0); System.out.println(System.currentTimeMillis()-s); } I ran the program multiple time, and the recursive one always ends up 3-4 times faster than the iterative one. What could be the main reason there that is causing the iterative one slower ?

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  • How do you add < or > to a summary tag in Visual studio?

    - by Tony
    How do you add < (less than) or (greater than) to a summary comment in visual studio? I am in Visual Studio 2008. I have a generic method: public bool IsMemberProtected<T>(Expression<Func<T, object>> expression) Would love to have a summary tag of something like this /// <summary> /// Determines whether a member is protected. /// /// Usage: IsMemberProtected<ExampleType>(x => x.Member) /// </summary> But when I do that, the tooltip for the property no longer works when a developer hovers over the method in code to view the summary tag. Thoughts?

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  • Advanced find in Rails

    - by jriff
    Hi all I really suck at Rails' finders besides the most obvious. I always resort to SQL when things get more advanced than Model.find(:all, :conditions => ['field>? and field<? and id in (select id from table)', 1,2]) I have this method: def self.get_first_validation_answer(id) a=find_by_sql(" select answers.*, answers_registrations.answer_text from answers_registrations left join answers on answers_registrations.answer_id=answers.id where (answers_registrations.question_id in (select id from questions where validation_question=true)) and (sale_registration_id=#{id}) limit 1 ").first a.answer_text || a.text if a end Can someone create a find method that gets me what I want? Regards, Jacob

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  • help with Zend dispatcher

    - by simple
    this is the Zend Controller Dispatcher Standart public function isDispatchable(Zend_Controller_Request_Abstract $request) { $className = $this->getControllerClass($request); echo 'is dispatchanble started'; var_dump($className); if (!$className) { return false; } var_dump(class_exists($className, false)); if (class_exists($className, false)) { return true; } $fileSpec = $this->classToFilename($className); $dispatchDir = $this->getDispatchDirectory(); $test = $dispatchDir . DIRECTORY_SEPARATOR . $fileSpec; return Zend_Loader::isReadable($test); } I need to set up custom modular structure and loading just using plugins (I need to setup the path where zend looks for controller), so I am stuck tracing down I came to the isDispatchable method that returns false and consequently the dispatching returns error . This method returns false because class_exists return false , it is surely has to do with auto loading ,but confused. help will be appreciated,though I got the feeling that I am looking at wrong place.

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  • How do I handle freeing unmanaged structures in C# on application close?

    - by LostKaleb
    I have a C# project in which i use several unmanaged C++ functions. More so, I also have static IntPtr that I use as parameters for those functions. I know that whenever I use them, I should implement IDisposable in that class and use a destructor to invoke the Dispose method, where I free the used IntPtr, as is said in the MSDN page. public void Dispose() { Dispose(true); GC.SuppressFinalize(this); } private void Dispose(bool disposing) { // Check to see if Dispose has already been called. if (!this.disposed) { if (disposing) { component.Dispose(); } CloseHandle(m_InstanceHandle); m_InstanceHandle = IntPtr.Zero; disposed = true; } } [System.Runtime.InteropServices.DllImport("Kernel32")] private extern static Boolean CloseHandle(IntPtr handle); However, when I terminate the application, I'm still left with a hanging process in TaskManager. I believe that it must be related to the used of the MarshalAs instruction in my structures: [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)] public struct SipxAudioCodec { [MarshalAs(UnmanagedType.ByValTStr, SizeConst=32)] public string CodecName; public SipxAudioBandwidth Bandwidth; public int PayloadType; } When I create such a structure should I also be careful to free the space it allocs using a destructor? [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)] public struct SipxAudioCodec { [MarshalAs(UnmanagedType.ByValTStr, SizeConst=32)] public string CodecName; public SipxAudioBandwidth Bandwidth; public int PayloadType; ~SipxAudioCodec() { Marshal.FreeGlobal(something...); } } Thanks in advance!

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  • Parent and child model interaction

    - by jminarik
    Hi, is it possible set something like wpf window owner in caliburn.micro ? I have PARENT VIEW MODEL, from this model I open CHILD SCREEN {VIEW MODEL} with this method: public IEnumerable<IResult> Open() { yield return new ShowWindow("ChatScreen") .InitializeWith(_service .DetailData(Account, _selectedFriend.Value.Nick), AvatarImage); } This method create a new WPF WINDOW - CHILD SCREEN and initialize CHILD VIEW MODEL with some variables. I would like set something like this CHILD_SCREEN.PARENT = PARENT_VIEW_MODEL. I would like achieve if I close PARENT VIEW MODEL that it close also all CHILD MODELS. Also it exist way how can I check if screen, in my situation WPF window, is active/inactive from MAIN VIEW MODEL?

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  • What's the deal with the hidden Throw when catching a ThreadAbortException?

    - by priehl
    I'm going through a book of general c# development, and I've come to the thread abort section. The book says something along the lines that when you call Thread.Abort() on another thread, that thread will throw a ThreadAbortException, and even if you tried to supress it it would automatically rethrow it, unless you did some bs that's generally frowned upon. Here's the simple example offered. using System; using System.Threading; public class EntryPoint { private static void ThreadFunc() { ulong counter = 0; while (true) { try { Console.WriteLine("{0}", counter++); } catch (ThreadAbortException) { // Attempt to swallow the exception and continue. Console.WriteLine("Abort!"); } } } static void Main() { try { Thread newThread = new Thread(new ThreadStart(EntryPoint.ThreadFunc)); newThread.Start(); Thread.Sleep(2000); // Abort the thread. newThread.Abort(); // Wait for thread to finish. newThread.Join(); } catch (Exception e) { Console.WriteLine(e.ToString()); } } } The book says: When your thread finishes processing the abort exception, the runtime implicitly rethrows it at the end of your exception handler. It’s the same as if you had rethrown the exception yourself. Therefore, any outer exception handlers or finally blocks will still execute normally. In the example, the call to Join won’t be waiting forever as initially expected. So i wrapped a try catch around the Thread.Abort() call and set a break point, expecting it to hit this, considering the text says "any outer exception handlers or finally blocks will still execute normally". BUT IT DOES NOT. I'm racking my brain to figure out why. Anyone have any thoughts on why this isn't the case? Is the book wrong? Thanks in advance.

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  • How to prevent robots from automatically filling up a form?

    - by sombe
    I'm trying to come up with a good enough anti-spamming mechanism to prevent automatically generated input. I've read that techniques like captcha, 1+1=? stuff work well, but they also present an extra step impeding the free quick use of the application. (I'm not looking for anything like that please). I've tried setting some hidden fields in all of my forms, with display: none; However, I'm almost certain a robot (which is essentially a program) can be configured to trace that form field id and simply not fill it. Do you implement/know of a good anti automatic-form-filling-robots method? Is there something that can be done seamlessly with HTML AND/OR server side processing, and be (almost) foolproof? (and please no JS, one could simply disable it, and there goes my anti-spam method). Btw I'm trying not to rely on sessions for this (like, counting how many times a button is clicked to prevent overloads).

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  • C# Constructor Problem When Using Generics

    - by Jimbo
    Please see an example of my code below: public class ScrollableCheckboxList { public List<ScrollableCheckboxItem> listitems; public void ScrollableCheckboxList<TModel>(IEnumerable<TModel> items, string valueField, string textField, string titleField) where TModel : class { listitems = new List<ScrollableCheckboxItem>(); foreach (TModel item in items) { Type t = typeof(TModel); PropertyInfo[] props = new [] { t.GetProperty(textField), t.GetProperty(valueField), t.GetProperty(titleField) }; listitems.Add(new ScrollableCheckboxItem { text = props[0].GetValue(item, null).ToString(), value = props[1].GetValue(item, null).ToString(), title = props[2].GetValue(item, null).ToString() }); } } } The code produces the following error: 'ScrollableCheckboxList': member names cannot be the same as their enclosing type This clearly means that there is a method in the class that has the same name as the class, but usually insinuates that the method is trying to return something (which is not allowed) In my case, all I have done is declare a constructor - why would this be a problem?

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  • ASP.NET Speed up DataView sorting/paging

    - by rlb.usa
    I have a page in ASP.NET where I'm using a Repeater to display a record listing. But it's slow as molasses, I've been tasked with speeding it up (sorting,paging). I've got it set up as follows: When user enters page, grab all of the data from the database (500 records, up to 4 relation'ed records) Store it all in Application["MyDataView"] On sort or paging, simply use the data view's internal sort/page method (no db calls) and rebind. I understand that databases can take time to query, but simply to have the DataView call it's sort method (no db calls) takes 10ish seconds, that's an alarmingly slow. Two questions: Why is it taking so long? How can I speed it up? A gridview is not possible.

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