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  • How to cache L2E entity without attach/detach?

    - by Eran Betzalel
    The following code will select a key/value table in the DB and will save the result to the cache: using (var db = new TestEntities()) { if(Cache["locName_" + inventoryLocationName] != null) return Cache["locName_" + inventoryLocationName]; var location = db.InventoryLocationsSet.FirstOrDefault( i => i.InventoryLocationName.Equals( inventoryLocationName, StringComparison.CurrentCultureIgnoreCase)); db.Detach(location); // ???? Cache["locName_" + inventoryLocationName] = location; return location; } But it doesn't work well when I'm trying to use the cached object. Of course, the problem is the different ObjectContext, so I use Attach/Detach and then the problem solves but with a codding horror price: db.Attach(locationFromCache); // ???? try { // Use location as foreign key db.SaveChanges(); } finally { db.Detach(locationFromCache); // ???? } So, how can I use cached objects without using attach/detach methods? What happens if more than one user will have to use this cached object? Should I put the whole thing in a CriticalSection?!

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  • Cannot show scene with Cocos2D when using UITabBarController

    - by gw1921
    Hi I'm new to Cocos2D but am having serious issues when trying to load a cocos scene in one of the UIViewControllers mixed with other normal UIKit UIViewControllers. My project uses a UITabBarController to manage four view controllers. Three are normal UIKit view controllers while one of them I want to use cocos2D for (to draw some sprites and animate them). The following is what I've done so far. In the applicationDidFinishLaunching method, I initialize cocos2D to use the window and take the first tabbarcontroller view: - (void)applicationDidFinishLaunching:(UIApplication *)application { if( ! [CCDirector setDirectorType:CCDirectorTypeDisplayLink] ) { [CCDirector setDirectorType:CCDirectorTypeDefault]; } [[CCDirector sharedDirector] setPixelFormat:kPixelFormatRGBA8888]; [CCTexture2D setDefaultAlphaPixelFormat:kTexture2DPixelFormat_RGBA8888]; [[CCDirector sharedDirector] setDisplayFPS:YES]; [[CCDirector sharedDirector] attachInView: window]; [[[CCDirector sharedDirector] openGLView] addSubview: tabBarController.view]; [window makeKeyAndVisible]; } Then in the third UIViewController code (where I want to use cocos2D) I do this (note: the view is being loaded from a NIB file which has a blank UIView and nothing else):\ - (void)viewDidLoad { [super viewDidLoad]; // 'scene' is an autorelease object. CCScene *myScene = [CCScene node]; // 'layer' is an autorelease object. MyLayer *myLayer = [MyLayer node]; // add layer as a child to scene [myScene addChild: myLayer]; [[CCDirector sharedDirector] runWithScene: myScene]; } However all I see is a blank white view and nothing else. If I call the following in viewdidLoad: [[CCDirector sharedDirector] attachInView: self.view]; The app crashes complaining that CCDirector is already attached. Please help!

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  • Create CAB file for ActiveX installation for IE

    - by vikasde
    I created a cab file that contains my activex using CABARC.exe. I also created an .inf file. My inf file looks like this: [version] signature="$CHICAGO$" AdvancedINF=2.0 [Add.Code] MySetup.exe=MySetup.exe [MySetup.exe] file-win32-x86=thiscab clsid={49892510-B520-4b35-8ADF-57084DD2F717} My html looks like this: <object name="secondobj" style='display:none' id='TestActivex' classid='CLSID:49892510-B520-4b35-8ADF-57084DD2F717' codebase='http://myurl/MySetup.cab#version=1,0,0,0'></object> I created the CABARC using the following commmand: C:\tools\Cab\BIN>CABARC.EXE N MySetup.cab MySetup.msi setup.inf I also added http://myurl to the trusted sites. Now the first time I opened the html page in IE, I saw a yellow bar, which I accepted. However it never installed the activex control. I dont see the installation in my program files nor can I see anything in the event logs or in the temporary download folder or in the "manage add-ons". Now everytime I open the webpage in IE, I do not see the yellow bar anymore. Can anybody help me out here please?

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  • How to get interpolated message in NHibernate.Validator

    - by SztupY
    Hi! I'm trying to integrate NHibernate.Validator with ASP.NET MVC client side validations, and the only problem I found is that I simply can't convert the non-interpolated message to a human-readable one. I thought this would be an easy task, but turned out to be the hardest part of the client-side validation. The main problem is that because it's not server-side, I actually only need the validation attributes that are being used, and I don't actually have an instance or anything else at hand. Here are some excerpts from what I've been already trying: // Get the the default Message Interpolator from the Engine IMessageInterpolator interp = _engine.Interpolator; if (interp == null) { // It is null?? Oh, try to create a new one interp = new NHibernate.Validator.Interpolator.DefaultMessageInterpolator(); } // We need an instance of the object that needs to be validated, se we have to create one object instance = Activator.CreateInstance(Metadata.ContainerType); // we enumerate all attributes of the property. For example we have found a PatternAttribute var a = attr as PatternAttribute; // it seems that the default message interpolator doesn't work, unless initialized if (interp is NHibernate.Validator.Interpolator.DefaultMessageInterpolator) { (interp as NHibernate.Validator.Interpolator.DefaultMessageInterpolator).Initialize(a); } // but even after it is initialized the following will throw a NullReferenceException, although all of the parameters are specified, and they are not null (except for the properties of the instance, which are all null, but this can't be changed) var message = interp.Interpolate(new InterpolationInfo(Metadata.ContainerType, instance, PropertyName, a, interp, a.Message)); I know that the above is a fairly complex code for a seemingly simple question, but I'm still stuck without solution. Is there any way to get the interpolated string out of NHValidator?

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  • .NET XML serialization

    - by ShdNx
    I would like to serialize and deserialize mixed data into XML. After some searches I found out that there were two ways of doing it: System.Runtime.Serialization.Formatters.Soap.SoapFormatter and System.Xml.Serialization.XmlSerializer. However, neither turned out to match my requirements, since: SoapFormatter doesn't support serialization of generic types XmlSerializer refuses to serialize types that implement IDictionary, not to mention that it's far less easy-to-use than "normal" serialization (e.g. see this SO question) I'm wondering if there exists an implementation that doesn't have these limitations? I have found attempts (for example CustomXmlSerializer and YAXLib as suggested in a related SO question), but they don't seem to work either. I was thinking about writing such serializer myself (though it certainly doesn't seem to be a very easy task), but then I find myself limited by the CLR, as I cannot create object instances of types that won't have a paramaterless constructor, even if I'm using reflection. I recall having read somewhere that implementations in System.Runtime.Serialization somehow bypass the normal object creation mechanism when deserializing objects, though I'm not sure. Any hints of how could this be done? Could somebody please point me to the right direction with this?

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  • get cells odf a JTable

    - by tuxou
    hi how to display a row of a jtable in a from of JTextField when click on the row, ( I need this to edit the data base from the JTable ) My table model static class TableDataModel extends AbstractTableModel { private List nomColonnes; private List tableau; public TableDataModel(List nomColonnes, List tableau){ this.nomColonnes = nomColonnes; majDonnees(tableau); } public void majDonnees(List nouvellesDonnees){ this.tableau = nouvellesDonnees; fireTableDataChanged(); } public int getRowCount(){ return tableau.size(); } public int getColumnCount(){ return nomColonnes.size(); } public Object getValueAt(int row, int col){ return ((ArrayList)( tableau.get(row))).get(col); } public String getColumnName(int col){ return nomColonnes.get(col).toString(); } public Class getColumnClass(int c) { return getValueAt(0,c).getClass(); } public boolean isCellEditable(int row, int col){ return true; } public void setValueAt(Object value, int row, int col) { ((List)tableau.get(row)).set(col,value); fireTableCellUpdated(row, col); //i suppose i should update the database here } }

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  • Help with Exception Handling in ASP.NET C# Application

    - by Shrewd Demon
    hi, yesterday i posted a question regarding the Exception Handling technique, but i did'nt quite get a precise answer, partly because my question must not have been precise. So i will ask it more precisely. There is a method in my BLL for authenticating user. If a user is authenticated it returns me the instance of the User class which i store in the session object for further references. the method looks something like this... public static UsersEnt LoadUserInfo(string email) { SqlDataReader reader = null; UsersEnt user = null; using (ConnectionManager cm = new ConnectionManager()) { SqlParameter[] parameters = new SqlParameter[1]; parameters[0] = new SqlParameter("@Email", email); try { reader = SQLHelper.ExecuteReader(cm.Connection, "sp_LoadUserInfo", parameters); } catch (SqlException ex) { //this gives me a error object } if (reader.Read()) user = new UsersDF(reader); } return user; } now my problem is suppose if the SP does not exist, then it will throw me an error or any other SQLException for that matter. Since this method is being called from my aspx.cs page i want to return some meaning full message as to what could have gone wrong so that the user understands that there was some problem and that he/she should retry logging-in again. but i can't because the method returns an instance of the User class, so how can i return a message instead ?? i hope i made it clear ! thank you.

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  • Any good tools or tips for fuzz testing Windows forms applications?

    - by Ogre Psalm33
    I'm maintaining a ~300K LOC C# legacy thick-client application with a Windows.Forms interface. The app is full of little bugs and quirks. For example, I recently discovered a bug where if a users edits and tabs (not clicks) through cells on a DataViewGrid, and leaves the a certain cell selected, the app gets an "Object reference not set to an instance of an object" exception. I discover (or get a bug report of) something new like this about every week or two. I've had enough, and was thinking of trying some sort of fuzz testing on the application to try to ferret out undiscovered issues. If I roll-my-own fuzz testing, I'd assume I at least need to be able to generate test harnesses that run pieces of my app (main window, FormX, FormY, FormZ, ...) independently and try to inject events into them. I was trying to look for tools suited for this, but so far have come up with nothing for Win Forms. (There seems to be no shortage of fuzz testing tools for web apps, however). Any helpful ideas?

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  • NullReferenceException when initializing NServiceBus within web application Application_Start method

    - by SteveBering
    I am running the 2.0 RTM of NServiceBus and am getting a NullReferenceException when my MessageModule binds the CurrentSessionContext to my NHibernate sessionfactory. From within my Application_Start, I call the following method: public static void WithWeb(IUnityContainer container) { log4net.Config.XmlConfigurator.Configure(); var childContainer = container.CreateChildContainer(); childContainer.RegisterInstance<ISessionFactory>(NHibernateSession.SessionFactory); var bus = NServiceBus.Configure.WithWeb() .UnityBuilder(childContainer) .Log4Net() .XmlSerializer() .MsmqTransport() .IsTransactional(true) .PurgeOnStartup(false) .UnicastBus() .ImpersonateSender(false) .LoadMessageHandlers() .CreateBus(); var activeBus = bus.Start(); container.RegisterInstance(typeof(IBus), activeBus); } When the bus is started, my message module starts with the following: public void HandleBeginMessage() { try { CurrentSessionContext.Bind(_sessionFactory.OpenSession()); } catch (Exception e) { _log.Error("Error occurred in HandleBeginMessage of NHibernateMessageModule", e); throw; } } In looking at my log, we are logging the following error when the bind method is called: System.NullReferenceException: Object reference not set to an instance of an object. at NHibernate.Context.WebSessionContext.GetMap() at NHibernate.Context.MapBasedSessionContext.set_Session(ISession value) at NHibernate.Context.CurrentSessionContext.Bind(ISession session) Apparently, there is some issue in getting access to the HttpContext. Should this call to configure NServiceBus occur later in the lifecycle than Application_Start? Or is there another workaround that others have used to get handlers working within an Asp.NET Web application? Thanks, Steve

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  • NSPredicate case-insensitive matching on to-many relationship

    - by Brian Webster
    I am implementing a search field where the user can type in a string to filter the items displayed in a view. Each object being displayed has a keywords to-many relationship, and I would like to be able to filter the objects based on their keywords. Each keyword object has a name property, so I've set up an NSPredicate to do the filtering that looks like this: NSPredicate* predicate = [NSPredicate predicateWithFormat:@"keywords.name CONTAINS %@", self.searchString]; This works, but the problem is that the search is case-sensitive, so if the keyword has a capital letter but the user types in all lowercase, no matches are found. I've tried the following modification: NSPredicate* predicate = [NSPredicate predicateWithFormat:@"keywords.name CONTAINS[c] %@", self.searchString]; But that doesn't make any difference in the case sensitivity of the matching. Is there a way to do this case-insensitive matching using just a plain predicate? Or will I need to implement some sort of custom accessor on the keyword class, e.g. write a lowercaseName method and match against a lowercased version of the search string instead? Addendum: After further exploration, the workaround of adding a custom accessor works OK for manual use of NSPredicate, but does not work at all when using NSFetchRequest with Core Data, which only works when querying attributes defined in the Core Data model.

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  • Synchronizing ASP.NET MVC action methods with ReaderWriterLockSlim

    - by James D
    Any obvious issues/problems/gotchas with synchronizing access (in an ASP.NET MVC blogging engine) to a shared object model (NHibernate, but it could be anything) at the Controller/Action level via ReaderWriterLockSlim? (Assume the object model is very large and expensive to build per-request, so we need to share it among requests.) Here's how a typical "Read Post" action would look. Enter the read lock, do some work, exit the read lock. public ActionResult ReadPost(int id) { // ReaderWriterLockSlim allows multiple concurrent writes; this method // only blocks in the unlikely event that some other client is currently // writing to the model, which would only happen if a comment were being // submitted or a new post were being saved. _lock.EnterReadLock(); try { // Access the model, fetch the post with specificied id // Pseudocode, etc. Post p = TheObjectModel.GetPostByID(id); ActionResult ar = View(p); return ar; } finally { // Under all code paths, we must release the read lock _lock.ExitReadLock(); } } Meanwhile, if a user submits a comment or an author authors a new post, they're going to need write access to the model, which is done roughly like so: [AcceptVerbs(HttpVerbs.Post)] public ActionResult SaveComment(/* some posted data */) { // try/finally omitted for brevity _lock.EnterWriteLock(); // Save the comment to the DB, update the model to include the comment, etc. _lock.ExitWriteLock(); } Of course, this could also be done by tagging those action methods with some sort of "synchronized" attribute... but however you do it, my question is is this a bad idea? ps. ReaderWriterLockSlim is optimized for multiple concurrent reads, and only blocks if the write lock is held. Since writes are so infrequent (1000s or 10,000s or 100,000s of reads for every 1 write), and since they're of such a short duration, the effect is that the model is synchronized , and almost nobody ever locks, and if they do, it's not for very long.

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  • Problem locating file in a classpath

    - by Gandalf StormCrow
    I'm trying to read in file content, ex : public void myMethod(){ FileInputStream fstream = new FileInputStream(fileLocation); // Get the object of DataInputStream DataInputStream in = new DataInputStream(fstream); BufferedReader br = new BufferedReader(new InputStreamReader(in)); String strLine; while ((strLine = br.readLine()) != null) { .... .... ..... end while end method And I have at the begining of the class body private String fileLocation; and at the end of a class I have a getter and setter for it. Now I'm trying inject this file location from spring inside bean from this class and I specify the init-method of this class. But I get error cannot find the specified file as if its not on a classpath but it is inside war file? I'm building the project with maven and I put file in src/main/resources This is the error I get when trying to read file : Error: src\main\resources\ids.txt (The system cannot find the path specified) That is when I tried this : FileInputStream fstream = new FileInputStream("src\\main\\resources\\ids.txt"); how to reference the properly from the classpath? EDIT When I edit my code according to @BalusC solution , here is how it looks but I still get null error : ClassLoader classLoader = Thread.currentThread().getContextClassLoader(); InputStream input = classLoader.getResourceAsStream("src/main/resources/ids.txt"); // Get the object of DataInputStream BufferedReader br = new BufferedReader(new InputStreamReader(input)); String strLine; while ((strLine = br.readLine()) != null) { .... .... ..... end while end method

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  • Rebinding and singleton-behaviour [NInject]

    - by Maximilian Csuk
    Hi! I have set up a NInject (using version 1.5) binding like this: Bind<ISessionFactory>().ToMethod<ISessionFactory>(ctx => { try { // create session factory, might fail because of database issues like wrong connection string } catch (Exception e) { throw new DatabaseException(e); } }).Using<SingletonBehavior>(); As you can see, this binding uses a singleton behavior but can also throw exception when something is not configured correctly, like a wrong connection string to the database. Now, when the creation of a session factory fails at first (throwing a database exception), NInject doesn't try to create the object again but always returns null. I would need NInject to check for null first and recreate when the instance is null, but of course not when there already is an instance successfully constructed (keeping it singleton). Like this: var a = Kernel.Get<ISessionFactory>(); // might fail, a = null // ... change some database settings var b = Kernel.Get<ISessionFactory>(); // might not fail anymore, b = ISessionFactory object Would I need to write a custom behavior or am I missing something else? Thanks for your answers!

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  • Problem with Unit testing of ASP.NET project (NullReferenceException when running the test)

    - by Alex
    Hi, I'm trying to create a bunch of MS visual studio unit tests for my n-tiered web app but for some reason I can't run those tests and I get the following error - "Object reference not set to an instance of an object" What I'm trying to do is testing of my data access layer where I use LINQ data context class to execute a certain function and return a result,however during the debugging process I found out that all the tests fail as soon as they get to the LINQ data context class and it has something to do with the connection string but I cant figure out what is the problem. The debugging of tests fails here(the second line): public EICDataClassesDataContext() : base(global::System.Configuration.ConfigurationManager.ConnectionStrings["EICDatabaseConnectionString"].ConnectionString, mappingSource) { OnCreated(); } And my test is as follows: TestMethod()] public void OnGetCustomerIDTest() { FrontLineStaffDataAccess target = new FrontLineStaffDataAccess(); // TODO: Initialize to an appropriate value string regNo = "jonh"; // TODO: Initialize to an appropriate value int expected = 10; // TODO: Initialize to an appropriate value int actual; actual = target.OnGetCustomerID(regNo); Assert.AreEqual(expected, actual); } The method which I call from DAL is: public int OnGetCustomerID(string regNo) { using (LINQDataAccess.EICDataClassesDataContext dataContext = new LINQDataAccess.EICDataClassesDataContext()) { IEnumerable<LINQDataAccess.GetCustomerIDResult> sProcCustomerIDResult = dataContext.GetCustomerID(regNo); int customerID = sProcCustomerIDResult.First().CustomerID; return customerID; } } So basically everything fails after it reaches the 1st line of DA layer method and when it tries to instantiate the LINQ data access class... I've spent around 10 hours trying to troubleshoot the problem but no result...I would really appreciate any help! UPDATE: Finally I've fixed this!!!!:) I dont know why but for some reasons in the app.config file the connection to my database was as follows: AttachDbFilename=|DataDirectory|\EICDatabase.MDF So what I did is I just changed the path and instead of |DataDirectory| I put the actual path where my MDF file sits,i.e C:\Users\1\Documents\Visual Studio 2008\Projects\EICWebSystem\EICWebSystem\App_Data\EICDatabase.mdf After I had done that it worked out!But still it's a bit not clear what was the problem...probably incorrect path to the database?My web.config of ASP.NET project contains the |DataDirectory|\EICDatabase.MDF path though..

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  • C# WPF DataBind boolean

    - by jtdangelo
    I have been using this website to learn a lot about C# for a while, but this is my first time posting a question. I look forward to hearing back from some of the seasoned C# veterans! I have been working on a C# 4.0 WPF project and need to figure out how to databind a boolean value. I have a reference to my Application.Current object in a window. My "App" object contains a boolean field called "Downloaded" that is true if the user has downloaded information from a web service. I need to databind a textbox's IsEnabled field to this Downloaded value. Any tips? Here is what I have come up with so far. (Any useful links to better learn WPF XAML are greatly appreciated!) C# Code: class MainWindow : Window { ... private App MyApp = App.Current as App; ... } XAML: <TextBox ... IsEnabled="{Binding Source=MyApp, Path=Downloaded}" /> James

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  • ERROR! (Using Excel's named ranges from C#)

    - by mcoolbeth
    In the following, I am trying to persist a set of objects in an excel worksheet. Each time the function is called to store a value, it should allocate the next cell of the A column to store that object. However, an exception is thrown by the Interop library on the first call to get_Range(). (right after the catch block) Does anyone know what I am doing wrong? private void AddName(string name, object value) { Excel.Worksheet jresheet; try { jresheet = (Excel.Worksheet)_app.ActiveWorkbook.Sheets["jreTemplates"]; } catch { jresheet = (Excel.Worksheet)_app.ActiveWorkbook.Sheets.Add(Type.Missing, Type.Missing, Type.Missing, Type.Missing); jresheet.Visible = Microsoft.Office.Interop.Excel.XlSheetVisibility.xlSheetVeryHidden; jresheet.Name = "jreTemplates"; jresheet.Names.Add("next", "A1", true, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing); } Excel.Range cell = jresheet.get_Range("next", Type.Missing); cell.Value2 = value; string address = ((Excel.Name)cell.Name).Name; _app.ActiveWorkbook.Names.Add(name, address, false, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing); cell = cell.get_Offset(1, 0); jresheet.Names.Add("next", ((Excel.Name)cell.Name).Name, true, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing); }

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  • Java - abstract class, equals(), and two subclasses

    - by msr
    Hello, I have an abstract class named Xpto and two subclasses that extend it named Person and Car. I have also a class named Test with main() and a method foo() that verifies if two persons or cars (or any object of a class that extends Xpto) are equals. Thus, I redefined equals() in both Person and Car classes. Two persons are equal when they have the same name and two cars are equal when they have the same registration. However, when I call foo() in the Test class I always get "false". I understand why: the equals() is not redefined in Xpto abstract class. So... how can I compare two persons or cars (or any object of a class that extends Xpto) in that foo() method? In summary, this is the code I have: public abstract class Xpto { } public class Person extends Xpto{ protected String name; public Person(String name){ this.name = name; } public boolean equals(Person p){ System.out.println("Person equals()?"); return this.name.compareTo(p.name) == 0 ? true : false; } } public class Car extends Xpto{ protected String registration; public Car(String registration){ this.registration = registration; } public boolean equals(Car car){ System.out.println("Car equals()?"); return this.registration.compareTo(car.registration) == 0 ? true : false; } } public class Teste { public static void foo(Xpto xpto1, Xpto xpto2){ if(xpto1.equals(xpto2)) System.out.println("xpto1.equals(xpto2) -> true"); else System.out.println("xpto1.equals(xpto2) -> false"); } public static void main(String argv[]){ Car c1 = new Car("ABC"); Car c2 = new Car("DEF"); Person p1 = new Person("Manel"); Person p2 = new Person("Manel"); foo(p1,p2); } }

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  • How to use bll, dal and model?

    - by bruno
    Dear all, In my company I must use a Bll, Dal and model layer for creating applications with a database. I've learned at school that every databasetable should be an object in my model. so I create the whole model of my database. Also I've learned that for every table (or model object) there should be a DAO created into the DAL. So I do this to. Now i'm stuck with the BLL classes. I can write a BLLclass for each DAO/ModelObject or I can write a BLLclass that combine some (logic) DAO's... Or i can write just one Bllclass that will manage everything. (this last one I'm sure it aint the best way..) What is the best practice to handle this Bll 'problem'? And a second question. If a bll is in need of tablecontent from an other table where it aint responsible for, whats the best way to get the content? Go ask on the responsible BLL or go directly to the DAO? I'm struggling with these questions the last 2 months, and i don't know what is the best way to handle it.

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  • Duck type testing with C# 4 for dynamic objects.

    - by Tracker1
    I'm wanting to have a simple duck typing example in C# using dynamic objects. It would seem to me, that a dynamic object should have HasValue/HasProperty/HasMethod methods with a single string parameter for the name of the value, property, or method you are looking for before trying to run against it. I'm trying to avoid try/catch blocks, and deeper reflection if possible. It just seems to be a common practice for duck typing in dynamic languages (JS, Ruby, Python etc.) that is to test for a property/method before trying to use it, then falling back to a default, or throwing a controlled exception. The example below is basically what I want to accomplish. If the methods described above don't exist, does anyone have premade extension methods for dynamic that will do this? Example: In JavaScript I can test for a method on an object fairly easily. //JavaScript function quack(duck) { if (duck && typeof duck.quack === "function") { return duck.quack(); } return null; //nothing to return, not a duck } How would I do the same in C#? //C# 4 dynamic Quack(dynamic duck) { //how do I test that the duck is not null, //and has a quack method? //if it doesn't quack, return null }

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  • Java Concurrency : Synchronized(this) => and this.wait() and this.notify()

    - by jens
    Hello Experts, I would appreciate your help in understand a "Concurrency Example" from: http://forums.sun.com/thread.jspa?threadID=735386 Qute Start: public synchronized void enqueue(T obj) { // do addition to internal list and then... this.notify(); } public synchronized T dequeue() { while (this.size()==0) { this.wait(); } return // something from the queue } Quote End: My Question is: Why is this code valid? = When I synchronize a method like "public synchronized" = then I synchronize on the "Instance of the Object == this". However in the example above: Calling "dequeue" I will get the "lock/monitor" on this Now I am in the dequeue method. As the list is zero, the calling thread will be "waited" From my understanding I have now a deadlock situation, as I will have no chance of ever enquing an object (from an nother thread), as the "dequeue" method is not yet finised and the dequeue "method" holds the lock on this: So I will never ever get the possibility to call "enequeue" as I will not get the "this" lock. Backround: I have exactly the same problem: I have some kind of connection pool (List of Connections) and need to block if all connections are checked. What is the correct way to synchronize the List to block, if size exceeds a limit or is zero? Thank you very much Jens

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  • Alternative Control Structures

    - by Brock Woolf
    I've been wondering about alternative ways to write control structures. One that you learn early on for if statements is a replacement for this: if ( x ) { // true } else { // false } with this (sometimes this is more readable compared to lots of brackets): x ? true : false It got me thinking. Can we replace anything else incase it's more readable. We of course replace if statements like this: if (a < b) { return true; } else { return false; } with things like this: return a < b; We can save a long if with something like this (pretty much same as the one above): bool xCollisionTrue = (object.xPos < aabb.maxX && object.xPos > aabb.minX); So those are the ones I can think of off the top of my head for the if statement and doing comparisons. So I'm wondering what about looping constructs, for, while, etc. Maybe the code obfuscators might have some ideas.

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  • user inheritance in django

    - by amateur
    Hi guys, I saw a couple of ways extending user information of users and decided to adopt the model inheritance method. for instance, I have : class Parent(User): contact_means = models.IntegerField() is_staff = False objects = userManager() Now it is done, I've downloaded django_registration to help me out with sending emails to new users. The thing is, instead of using registration forms to register new user, I want to to invoke the email sending/acitvation capability of django_registration. So my workflow is: 1. add new Parent object in admin page. 2. send email My problem is, the django-registration creates a new registration profile together with a new user in the user table. how do I tweak this such that I am able to add the user entry into the custom user table. I have tried to create a modelAdmin and alter the save_model method to launch the create_inactive_user from django_registration, however I do not how to save the user object generated from django_registration into my Parent table when I have using model inheritance and I do not have a Foreign key attribute in my parent model.

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  • nHibernate Self Join Mapping

    - by kmoo01
    Hi Guys, This is probably incredibly simple, but I just cant see the wood for the trees at the moment. For brevity, I would like to model a word object, that has related words to it (synonyms), In doing so I could have the following mappings: <class name="Word" table="bs_word"> <id name="Id" column="WordId" type="Int32" unsaved-value="-1"> <generator class="native"> <param name="sequence"></param> </generator> </id> <property name="Key" column="word" type="String" length="50" /> <many-to-one name="SynonymGroup" class="BS.Core.Domain.Synonym, BS.Core" column="SynonymId" lazy="false"/> <class name="Synonym" table="bs_Synonym"> <id name="Id" column="SynonymId" type="Int32" unsaved-value="-1"> <generator class="native"> <param name="sequence"></param> </generator> </id> <property name="Alias" column="Alias" type="String" length="50" /> <bag name="Words" cascade="none" lazy="false" inverse="true"> <key column="SynonymId" /> <one-to-many class="Word" /> </bag> Mapping it like this would mean for a given word, I can access related words (synonyms) like this: word.SynonymGroup.Words However I would like to know if it is possible to map a bag of objects on an instance of a word object...if that makes sense, so I can access the related words like this: word.Words I've tried playing around with the map element, and composite elements, all to no avail - so I was wondering if some kind person could point me in the right direction? ta, kmoo01

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  • Getting DirectoryNotFoundException when trying to Connect to Device with CoreCon API

    - by ageektrapped
    I'm trying to use the CoreCon API in Visual Studio 2008 to programmatically launch device emulators. When I call device.Connect(), I inexplicably get a DirectoryNotFoundException. I get it if I try it in PowerShell or in C# Console Application. Here's the code I'm using: static void Main(string[] args) { DatastoreManager dm = new DatastoreManager(1033); Collection<Platform> platforms = dm.GetPlatforms(); foreach (var p in platforms) { Console.WriteLine("{0} {1}", p.Name, p.Id); } Platform platform = platforms[3]; Console.WriteLine("Selected {0}", platform.Name); Device device = platform.GetDevices()[0]; device.Connect(); Console.WriteLine("Device Connected"); SystemInfo info = device.GetSystemInfo(); Console.WriteLine("System OS Version:{0}.{1}.{2}", info.OSMajor, info.OSMinor, info.OSBuildNo); Console.ReadLine(); } My question: Does anyone know why I'm getting this error? I'm running this on WinXP 32-bit, plain jane Visual Studio 2008 Pro. I imagine it's some config issue since I can't do it from a Console app or PowerShell. Here's the stack trace as requested: System.IO.DirectoryNotFoundException was unhandled Message="The system cannot find the path specified.\r\n" Source="Device Connection Manager" StackTrace: at Microsoft.VisualStudio.DeviceConnectivity.Interop.ConManServerClass.ConnectDevice() at Microsoft.SmartDevice.Connectivity.Device.Connect() at ConsoleApplication1.Program.Main(String[] args) in C:\Documents and Settings\Thomas\Local Settings\Application Data\Temporary Projects\ConsoleApplication1\Program.cs:line 23 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart() InnerException:

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  • How do I match complete XML objects in a string?

    - by cyclotis04
    I'm attempting to find complete XML objects in a string. They have been placed in the string by an XmlSerializer, but may or may not be complete. I've toyed with the idea of using a regular expression, because it seems like the kind of thing they were built for, except for the fact that I'm trying to parse XML. I'm trying to find complete objects in the form: <?xml version="1.0"?> <type> <field>value</field> ... </type> My thought was a regex to find <?xml version="1.0"?><type> and </type>, but if a field has the same name as type, it obviously won't work. There's plenty of documentation on XML parsers, but they seem to all need a complete, fully-formed document to parse. My XML objects can be in a string surrounded by pretty much anything else (including other complete objects). hw<e>reR@lot$0fr@ndm&nchrs%<?xml version="1.0"?><type><field>...</field>...</type>@ndH#r$omOre!!>nuT6erjc?y!<?xml version="1.0"?><type><field>...</field>...</type>ty!=] A regex would be able to match a string while excluding the random characters, but not find a complete XML object. I'd like some way to extract an object, parse it with a serializer, then repeat until the string contains no more valid objects.

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