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• Best practice when removing entity regarding mappedBy collections?

  - by Daniel Bleisteiner

  I'm still kind of undecided which is the best practice to handle em.remove(entity) with this entity being in several collections mapped using mappedBy in JPA. Consider an entity like a Property that references three other entities: a Descriptor, a BusinessObject and a Level entity. The mapping is defined using @ManyToOne in the Property entity and using @OneToMany(mappedBy...) in the other three objects. That inverse mapping is defined because there are some situations where I need to access those collections. Whenever I remove a Property using em.remove(prop) this element is not automatically removed from managed entities of the other three types. If I don't care about that and the following page load (webapp) doesn't reload those entities the Property is still found and some decisions might be taken that are no longer true. The inverse mappings may become quite large and though I don't want to use something like descriptor.getProperties().remove(prop) because it will load all those properties that might have been lazy loaded until then. So my currently preferred way is to refresh the entity if it is managed: if (em.contains(descriptor)) em.refresh(descriptor) - which unloads a possibly loaded collection and triggers a reload upon the next access. Is there another feasible way to handle all those mappedBy collections of already loaded entites?

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• NHibernate Entity code conversion from #C to VB.Net

  - by CoderRoller

  Hello and thanks for your help in advance. I am starting on the NHibernate world and i am experimenting with the NHibernate CookBook recipes, i am trying to set a base entity class for my entities and this is the C# code for this. I would like to know whats the VB.NET version so i can implement it in my sample project. This is the C# code: public abstract class Entity<TId> { public virtual TId Id { get; protected set; } public override bool Equals(object obj) { return Equals(obj as Entity<TId>); } private static bool IsTransient(Entity<TId> obj) { return obj != null && Equals(obj.Id, default(TId)); } private Type GetUnproxiedType() { return GetType(); } public virtual bool Equals(Entity<TId> other) { if (other == null) return false; if (ReferenceEquals(this, other)) return true; if (!IsTransient(this) && !IsTransient(other) && Equals(Id, other.Id)) { var otherType = other.GetUnproxiedType(); var thisType = GetUnproxiedType(); return thisType.IsAssignableFrom(otherType) || otherType.IsAssignableFrom(thisType); } return false; } public override int GetHashCode() { if (Equals(Id, default(TId))) return base.GetHashCode(); return Id.GetHashCode(); } } I tried using an online converter but puts a Nothing reference in place of default(TId) that doesn't seem right to me that's why I request for help: Private Shared Function IsTransient(obj As Entity(Of TId)) As Boolean Return obj IsNot Nothing AndAlso Equals(obj.Id, Nothing) End Function I Would appreciate the insight you may give me on the subject.

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• Different EF Property DataType than Storage Layer Possible?

  - by dj_kyron

  Hi, I am putting together a WCF Data Service for PatientEntities using Entity Framework. My solution needs to address these requirements: Property DateOfBirth of entity Patient is stored in SQL Server as string. It would be ideal if the entity class did not also use the "string" type but rather a DateTime type. (I would expect this to be possible since we're abstracting away from the storage layer). Where could a conversion mechanism be put in place that would convert to and from DateTime/string so that the entity and SQL Server are in sync?. I cannot change the storage layer's structure, so I have to work around it. WCF Data Services (Read-only, so no need for saving changes) need to be used since clients will be able to use LINQ expressions to consume the service. They can generate results based on any given query scenario they need and not be constrained by a single method such as GetPatient(int ID). I've tried to use DTOs, but run into problem of mapping the ObjectContext to a DTO, I don't think that is theoretically possible...or too complicated if it is. I've tried to use Self Tracking Entities but they require the metadata from the .edmx file if I'm correct, and this isn't allowing a different property data type. I also want to add customizations to my Entity getter methods so that a property "MRN" of type "string" needs to have .Replace("MR~", string.Empty) performed before it is returned. I can add this to the getter methods but the problem with that is Entity Framework will overwrite that next time it refreshes the entity classes. Is there a permanent place I can put these? Should I use POCO instead? How would that work with WCF Data Services? Where would the service grab the metadata?

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• JPA Entity Manager resource handling

  - by chiragshahkapadia

  Every time I call JPA method its creating entity and binding query. My persistence properties are: <property name="hibernate.dialect" value="org.hibernate.dialect.Oracle10gDialect"/> <property name="hibernate.cache.provider_class" value="net.sf.ehcache.hibernate.SingletonEhCacheProvider"/> <property name="hibernate.cache.use_second_level_cache" value="true"/> <property name="hibernate.cache.use_query_cache" value="true"/> And I am creating entity manager the way shown below: emf = Persistence.createEntityManagerFactory("pu"); em = emf.createEntityManager(); em = Persistence.createEntityManagerFactory("pu").createEntityManager(); Is there any nice way to manage entity manager resource instead create new every time or any property can set in persistence. Remember it's JPA. See below binding log every time : 15:35:15,527 INFO [AnnotationBinder] Binding entity from annotated class: * 15:35:15,527 INFO [QueryBinder] Binding Named query: * = * 15:35:15,527 INFO [QueryBinder] Binding Named query: * = * 15:35:15,527 INFO [QueryBinder] Binding Named query: 15:35:15,527 INFO [QueryBinder] Binding Named query: 15:35:15,527 INFO [QueryBinder] Binding Named query: 15:35:15,527 INFO [QueryBinder] Binding Named query: 15:35:15,527 INFO [QueryBinder] Binding Named query: 15:35:15,527 INFO [QueryBinder] Binding Named query: 15:35:15,527 INFO [QueryBinder] Binding Named query: 15:35:15,527 INFO [EntityBinder] Bind entity com.* on table * 15:35:15,542 INFO [HibernateSearchEventListenerRegister] Unable to find org.hibernate.search.event.FullTextIndexEventListener on the classpath. Hibernate Search is not enabled. 15:35:15,542 INFO [NamingHelper] JNDI InitialContext properties:{} 15:35:15,542 INFO [DatasourceConnectionProvider] Using datasource: 15:35:15,542 INFO [SettingsFactory] RDBMS: and Real Application Testing options 15:35:15,542 INFO [SettingsFactory] JDBC driver: Oracle JDBC driver, version: 9.2.0.1.0 15:35:15,542 INFO [Dialect] Using dialect: org.hibernate.dialect.Oracle10gDialect 15:35:15,542 INFO [TransactionFactoryFactory] Transaction strategy: org.hibernate.transaction.JDBCTransactionFactory 15:35:15,542 INFO [TransactionManagerLookupFactory] No TransactionManagerLookup configured (in JTA environment, use of read-write or transactional second-level cache is not recomm ended) 15:35:15,542 INFO [SettingsFactory] Automatic flush during beforeCompletion(): disabled 15:35:15,542 INFO [SettingsFactory] Automatic session close at end of transaction: disabled 15:35:15,542 INFO [SettingsFactory] JDBC batch size: 15 15:35:15,542 INFO [SettingsFactory] JDBC batch updates for versioned data: disabled 15:35:15,542 INFO [SettingsFactory] Scrollable result sets: enabled 15:35:15,542 INFO [SettingsFactory] JDBC3 getGeneratedKeys(): disabled 15:35:15,542 INFO [SettingsFactory] Connection release mode: auto 15:35:15,542 INFO [SettingsFactory] Default batch fetch size: 1 15:35:15,542 INFO [SettingsFactory] Generate SQL with comments: disabled 15:35:15,542 INFO [SettingsFactory] Order SQL updates by primary key: disabled 15:35:15,542 INFO [SettingsFactory] Order SQL inserts for batching: disabled 15:35:15,542 INFO [SettingsFactory] Query translator: org.hibernate.hql.ast.ASTQueryTranslatorFactory 15:35:15,542 INFO [ASTQueryTranslatorFactory] Using ASTQueryTranslatorFactory 15:35:15,542 INFO [SettingsFactory] Query language substitutions: {} 15:35:15,542 INFO [SettingsFactory] JPA-QL strict compliance: enabled 15:35:15,542 INFO [SettingsFactory] Second-level cache: enabled 15:35:15,542 INFO [SettingsFactory] Query cache: enabled 15:35:15,542 INFO [SettingsFactory] Cache region factory : org.hibernate.cache.impl.bridge.RegionFactoryCacheProviderBridge 15:35:15,542 INFO [RegionFactoryCacheProviderBridge] Cache provider: net.sf.ehcache.hibernate.SingletonEhCacheProvider 15:35:15,542 INFO [SettingsFactory] Optimize cache for minimal puts: disabled 15:35:15,542 INFO [SettingsFactory] Structured second-level cache entries: disabled 15:35:15,542 INFO [SettingsFactory] Query cache factory: org.hibernate.cache.StandardQueryCacheFactory 15:35:15,542 INFO [SettingsFactory] Statistics: disabled 15:35:15,542 INFO [SettingsFactory] Deleted entity synthetic identifier rollback: disabled 15:35:15,542 INFO [SettingsFactory] Default entity-mode: pojo 15:35:15,542 INFO [SettingsFactory] Named query checking : enabled 15:35:15,542 INFO [SessionFactoryImpl] building session factory 15:35:15,542 INFO [SessionFactoryObjectFactory] Not binding factory to JNDI, no JNDI name configured 15:35:15,542 INFO [UpdateTimestampsCache] starting update timestamps cache at region: org.hibernate.cache.UpdateTimestampsCache 15:35:15,542 INFO [StandardQueryCache] starting query cache at region: org.hibernate.cache.StandardQueryCache

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• Fix: WCF - The type provided as the Service attribute value in the ServiceHost directive could not

  - by Ken Cox [MVP]

  I wanted to expose some raw data to users in my current ASP.NET 3.5 web site project. I created a subdirectory called ‘datafeeds’ and added a WCF Data Service. I wired the dataservice up to the Entity Framework class and, on running the ItemDataService.svc file, was greeted with: The type  <> provided as the Service attribute value in the ServiceHost directive could not be found So why couldn’t it find the class? It was right there in the… oops! Instead of putting the ItemDataService.vb...(read more)

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• ASP.NET MVC3 checkbox dropdownlist create [migrated]

  - by user95381

  i'm new in asp.net MVC and I/m use view model to poppulate the dropdown list and group of checkboxes. I use SQL Server 2012, where have many to many relationships between Students - Books; Student - Cities. I need collect StudentName, one city and many books for one student. I have next questions: 1. How can I get the values from database to my StudentBookCityViewModel? 2. How can I save the values to my database in [HttpPost] Create method? Here is the code: MODEL public class Student { public int StudentId { get; set; } public string StudentName { get; set; } public ICollection<Book> Books { get; set; } public ICollection<City> Cities { get; set; } } public class Book { public int BookId { get; set; } public string BookName { get; set; } public bool IsSelected { get; set; } public ICollection<Student> Students { get; set; } } public class City { public int CityId { get; set; } public string CityName { get; set; } public bool IsSelected { get; set; } public ICollection<Student> Students { get; set; } } VIEW MODEL public class StudentBookCityViewModel { public string StudentName { get; set; } public IList<Book> Books { get; set; } public StudentBookCityViewModel() { Books = new[] { new Book {BookName = "Title1", IsSelected = false}, new Book {BookName = "Title2", IsSelected = false}, new Book {BookName = "Title3", IsSelected = false} }.ToList(); } public string City { get; set; } public IEnumerable<SelectListItem> CityValues { get { return new[] { new SelectListItem {Value = "Value1", Text = "Text1"}, new SelectListItem {Value = "Value2", Text = "Text2"}, new SelectListItem {Value = "Value3", Text = "Text3"} }; } } } Context public class EFDbContext : DbContext{ public EFDbContext(string connectionString) { Database.Connection.ConnectionString = connectionString; } public DbSet<Book> Books { get; set; } public DbSet<Student> Students { get; set; } public DbSet<City> Cities { get; set; } protected override void OnModelCreating(DbModelBuilder modelBuilder) { modelBuilder.Entity<Book>() .HasMany(x => x.Students).WithMany(x => x.Books) .Map(x => x.MapLeftKey("BookId").MapRightKey("StudentId").ToTable("StudentBooks")); modelBuilder.Entity<City>() .HasMany(x => x.Students).WithMany(x => x.Cities) .Map(x => x.MapLeftKey("CityId").MapRightKey("StudentId").ToTable("StudentCities")); } } Controller public ActionResult Create() { return View(); } [HttpPost] public ActionResult Create() { //I don't understand how I can save values to db context.SaveChanges(); return RedirectToAction("Index"); } View @model UsingEFNew.ViewModels.StudentBookCityViewModel @using (Html.BeginForm()) { Your Name: @Html.TextBoxFor(model = model.StudentName) <div>Genre:</div> <div> @Html.DropDownListFor(model => model.City, Model.CityValues) </div> <div>Books:</div> <div> @for (int i = 0; i < Model.Books.Count; i++) { <div> @Html.HiddenFor(x => x.Books[i].BookId) @Html.CheckBoxFor(x => x.Books[i].IsSelected) @Html.LabelFor(x => x.Books[i].IsSelected, Model.Books[i].BookName) </div> } </div> <div> <input id="btnSubmit" type="submit" value="Submit" /> </div> </div> }

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• Local Entities with NHibernate

  - by Ricardo Peres

  You may know that Entity Framework Code First has a nice property called Local which lets you iterate through all the entities loaded by the current context (first level cache). This comes handy at times, so I decided to check if it would be difficult to have it on NHibernate. It turned out it is not, so here it is! Another nice addition to an NHibernate toolbox! public static class SessionExtensions { public static IEnumerable<T> Local<T>(this ISession session) { ISessionImplementor impl = session.GetSessionImplementation(); IPersistenceContext pc = impl.PersistenceContext; foreach (Object key in pc.EntityEntries.Keys) { if (key is T) { yield return ((T) key); } } } } //simple usage IEnumerable<Post> localPosts = session.Local<Post>(); SyntaxHighlighter.config.clipboardSwf = 'http://alexgorbatchev.com/pub/sh/2.0.320/scripts/clipboard.swf'; SyntaxHighlighter.brushes.CSharp.aliases = ['c#', 'c-sharp', 'csharp']; SyntaxHighlighter.all();

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• The underlying provider failed on Open

  - by aghausman12

  The underlying provider failed on Open is an entity framework error and with a simple fix it is little difficult to sort out what is going wrong. 1) if you are using IIS 7 with Integrated Security in connection string. Make sure your IIS user have appropriate permissions to access database. 2) If you are using Visual Studio built in Web Server and facing this issue. Simple fix is to either re-start Visual Studio or Kill the process of Web Server which is (WebDev.WebServer*.exe). I was in the second...(read more)

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• delete elements in xml?

  - by fayer

  i've got some elements in a xml document i want to delete. so i want to create another xml document without those elements. here is an example of how it looks like at the moment: <entity id="1000070"> <name>apple</name> <type>category</type> <entities> <entity id="7002870"> <name>mac</name> <type>category</type> <entities> <entity id="7002907"> <name>leopard</name> <type>sub-category</type> <entities> <entity id="7024080"> <name>safari</name> <type>subject</type> </entity> <entity id="7024701"> <name>finder</name> <type>subject</type> </entity> </entities> </entity> </entities> </entity> <entity id="7024080"> <name>iphone</name> <type>category</type> <entities> <entity id="7024080"> <name>3g</name> <type>sub-category</type> </entity> <entity id="7024701"> <name>3gs</name> <type>sub-category</type> </entity> </entities> </entity> <entity id="7024080"> <name>ipad</name> <type>category</type> </entity> </entities> </entity> i want to create another xml document without the sub-category and subject elements. so the new one will look like this: <entity id="1000070"> <name>apple</name> <type>category</type> <entities> <entity id="7002870"> <name>mac</name> <type>category</type> </entity> <entity id="7024080"> <name>iphone</name> <type>category</type> </entity> <entity id="7024080"> <name>ipad</name> <type>category</type> </entity> </entities> </entity> should i use simplexml/php or xslt to do this? are there other ways? would be great with some code examples...thanks!

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• RIA Services Repository Save does not work!?

  - by Savvas Sopiadis

  Hello everybody! Doing my first SL4 MVVM RIA based application and i ran into the following situation: updating a record (EF4,NO-POCOS!!) in the SL-client seems to take place, but values in the dbms are unchanged. Debugging with Fiddler the message on save is (amongst others): EntityActions.nil? b9http://schemas.microsoft.com/2003/10/Serialization/Arrays^HasMemberChanges?^Id?^ Operation?Update I assume that this says only: hey! the dbms should do an update on this record, AND nothing more! Is that right?! I 'm using a generic repository like this: public class Repository<T> : IRepository<T> where T : class { IObjectSet<T> _objectSet; IObjectContext _objectContext; public Repository(IObjectContext objectContext) { this._objectContext = objectContext; _objectSet = objectContext.CreateObjectSet<T>(); } public IQueryable<T> AsQueryable() { return _objectSet; } public IEnumerable<T> GetAll() { return _objectSet.ToList(); } public IEnumerable<T> Find(Expression<Func<T, bool>> where) { return _objectSet.Where(where); } public T Single(Expression<Func<T, bool>> where) { return _objectSet.Single(where); } public T First(Expression<Func<T, bool>> where) { return _objectSet.First(where); } public void Delete(T entity) { _objectSet.DeleteObject(entity); } public void Add(T entity) { _objectSet.AddObject(entity); } public void Attach(T entity) { _objectSet.Attach(entity); } public void Save() { _objectContext.SaveChanges(); } } The DomainService Update Method is the following: [Update] public void UpdateCulture(Culture currentCulture) { if (currentCulture.EntityState == System.Data.EntityState.Detached) { this.cultureRepository.Attach(currentCulture); } this.cultureRepository.Save(); } I know that the currentCulture-Entity is detached. What confuses me (amongst other things) is this: is the _objectContext still alive? (which means it "will be"??? aware of the changes made to record, so simply calling Attach() and then Save() should be enough!?!?) What am i missing? Development Environment: VS2010RC - Entity Framework 4 (no POCOs) Thanks in advance

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• Interesting things – Twitter annotations and your phone as a web server

  - by jamiet

  I overheard/read a couple of things today that really made me, data junkie that I am, take a step back and think, “Hmmm, yeah, that could be really interesting” and I wanted to make a note of them here so that (a) I could bring them to the attention of anyone that happens to read this and (b) I can maybe come back here in a few years and see if either of these have come to fruition. Your phone as a web server While listening to Jon Udell’s (twitter) “Interviews with Innovators Podcast” today in which he interviewed Herbert Van de Sompel (twitter) about his Momento project. During the interview Jon and Herbert made the following remarks: Jon: [some people] really had this vision of a web of servers, the notion that every node on the internet, every connected entity, is potentially a server and a client…we can see where we’re getting to a point where these endpoint devices we have in our pockets are going to be massively capable and it may be in the not too distant future that significant chunks of the web archive will be cached all over the place including on your own machine… Herbert: wasn’t it Opera who at one point turned your browser into a server? That really got my brain ticking. We all carry a mobile phone with us and therefore we all potentially carry a mobile web server with us as well and to my mind the only thing really stopping that from happening is the capabilities of the phone hardware, the capabilities of the network infrastructure and the will to just bloody do it. Certainly all the standards required for addressing a web server on a phone already exist (to this uninitiated observer DNS and IPv6 seem to solve that problem) so why not? I tweeted about the idea and Rory Street answered back with “why would you want a phone to be a web server?”: Its a fair question and one that I would like to try and answer. Mobile phones are increasingly becoming our window onto the world as we use them to upload messages to Twitter, record our location on FourSquare or interact with our friends on Facebook but in each of these cases some other service is acting as our intermediary; to see what I’m thinking you have to go via Twitter, to see where I am you have to go to FourSquare (I’m using ‘I’ liberally, I don’t actually use FourSquare before you ask). Why should this have to be the case? Why can’t that data be decentralised? Why can’t we be masters of our own data universe? If my phone acted as a web server then I could expose all of that information without needing those intermediary services. I see a time when we can pass around URLs such as the following: http://jamiesphone.net/location/current - Where is Jamie right now? http://jamiesphone.net/location/2010-04-21 – Where was Jamie on 21st April 2010? http://jamiesphone.net/thoughts/current – What’s on Jamie’s mind right now? http://jamiesphone.net/blog – What documents is Jamie sharing with me? http://jamiesphone.net/calendar/next7days – Where is Jamie planning to be over the next 7 days? and those URLs get served off of the phone in our pockets. If we govern that data then we can control who has access to it and (crucially) how long its available for. Want to wipe yourself off the face of the web? its pretty easy if you’re in control of all the data – just turn your phone off. None of this exists today but I look forward to a time when it does. Opera really were onto something last June when they announced Opera Unite (admittedly Unite only works because Opera provide an intermediary DNS-alike system – it isn’t totally decentralised). Opening up Twitter annotations Last week Twitter held their first developer conference called Chirp where they announced an upcoming new feature called ‘Twitter Annotations’; in short this will allow us to attach metadata to a Tweet thus enhancing the tweet itself. Think of it as a richer version of hashtags. To think of it another way Twitter are turning their data into a humongous Entity-Attribute-Value or triple-tuple store. That alone has huge implications both for the web and Twitter as a whole – the ability to enrich that 140 characters data and thus make it more useful is indeed compelling however today I stumbled upon a blog post from Eugene Mandel entitled Tweet Annotations – a Way to a Metadata Marketplace? where he proposed the idea of allowing tweets to have metadata added by people other than the person who tweeted the original tweet. This idea really fascinated me especially when I read some of the potential uses that Eugene and his commenters suggested. They included: Amazon could attach an ISBN to a tweet that mentions a book. Specialist clients apps for book lovers could be built up around this metadata. Advertisers could pay to place adverts in metadata. The revenue generated from those adverts could be shared with the tweeter or people who add the metadata. Granted, allowing anyone to add metadata to a tweet has the potential to create a spam problem the like of which we haven’t even envisaged but spam hasn’t halted the growth of the web and neither should it halt the growth of data annotations either. The original tweeter should of course be able to determine who can add metadata and whether it should be moderated. As Eugene says himself: Opening publishing tweet annotations to anyone will open the way to a marketplace of metadata where client developers, data mining companies and advertisers can add new meaning to Twitter and build innovative businesses. What Eugene and his followers did not mention is what I think is potentially the most fascinating use of opening up annotations. Google’s success today is built on their page rank algorithm that measures the validity of a web page by the number of incoming links to it and the page rank of the sites containing those links – its a system built on reputation. Twitter annotations could open up a new paradigm however – let’s call it People rank- where reputation can be measured by the metadata that people choose to apply to links and the websites containing those links. Its not hard to see why Google and Microsoft have paid big bucks to get access to the Twitter firehose! Neither of these features, phones as a web server or the ability to add annotations to other people’s tweets, exist today but I strongly believe that they could dramatically enhance the web as we know it today. I hope to look back on this blog post in a few years in the knowledge that these ideas have been put into place. @Jamiet Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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• Entity Framework POCO Template for .NET 3.5

  If you are using Visual Studio 2010 and targeting .NET 3.5, you can still use the new T4 POCO template generation. I discovered this accidentally. (How else?) When you attempt to add a new code generation item from the model, there will be no templates available:   But if you click on Online Templates, there is an ADO.NET POCO Generator created by Microsoft: And it does the job as expected! Nice!...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• The fastest way to resize images from ASP.NET. And it’s (more) supported-ish.

  - by Bertrand Le Roy

  I’ve shown before how to resize images using GDI, which is fairly common but is explicitly unsupported because we know of very real problems that this can cause. Still, many sites still use that method because those problems are fairly rare, and because most people assume it’s the only way to get the job done. Plus, it works in medium trust. More recently, I’ve shown how you can use WPF APIs to do the same thing and get JPEG thumbnails, only 2.5 times faster than GDI (even now that GDI really ultimately uses WIC to read and write images). The boost in performance is great, but it comes at a cost, that you may or may not care about: it won’t work in medium trust. It’s also just as unsupported as the GDI option. What I want to show today is how to use the Windows Imaging Components from ASP.NET APIs directly, without going through WPF. The approach has the great advantage that it’s been tested and proven to scale very well. The WIC team tells me you should be able to call support and get answers if you hit problems. Caveats exist though. First, this is using interop, so until a signed wrapper sits in the GAC, it will require full trust. Second, the APIs have a very strong smell of native code and are definitely not .NET-friendly. And finally, the most serious problem is that older versions of Windows don’t offer MTA support for image decoding. MTA support is only available on Windows 7, Vista and Windows Server 2008. But on 2003 and XP, you’ll only get STA support. that means that the thread safety that we so badly need for server applications is not guaranteed on those operating systems. To make it work, you’d have to spin specialized threads yourself and manage the lifetime of your objects, which is outside the scope of this article. We’ll assume that we’re fine with al this and that we’re running on 7 or 2008 under full trust. Be warned that the code that follows is not simple or very readable. This is definitely not the easiest way to resize an image in .NET. Wrapping native APIs such as WIC in a managed wrapper is never easy, but fortunately we won’t have to: the WIC team already did it for us and released the results under MS-PL. The InteropServices folder, which contains the wrappers we need, is in the WicCop project but I’ve also included it in the sample that you can download from the link at the end of the article. In order to produce a thumbnail, we first have to obtain a decoding frame object that WIC can use. Like with WPF, that object will contain the command to decode a frame from the source image but won’t do the actual decoding until necessary. Getting the frame is done by reading the image bytes through a special WIC stream that you can obtain from a factory object that we’re going to reuse for lots of other tasks: var photo = File.ReadAllBytes(photoPath); var factory = (IWICComponentFactory)new WICImagingFactory(); var inputStream = factory.CreateStream(); inputStream.InitializeFromMemory(photo, (uint)photo.Length); var decoder = factory.CreateDecoderFromStream( inputStream, null, WICDecodeOptions.WICDecodeMetadataCacheOnLoad); var frame = decoder.GetFrame(0); We can read the dimensions of the frame using the following (somewhat ugly) code: uint width, height; frame.GetSize(out width, out height); This enables us to compute the dimensions of the thumbnail, as I’ve shown in previous articles. We now need to prepare the output stream for the thumbnail. WIC requires a special kind of stream, IStream (not implemented by System.IO.Stream) and doesn’t directlyunderstand .NET streams. It does provide a number of implementations but not exactly what we need here. We need to output to memory because we’ll want to persist the same bytes to the response stream and to a local file for caching. The memory-bound version of IStream requires a fixed-length buffer but we won’t know the length of the buffer before we resize. To solve that problem, I’ve built a derived class from MemoryStream that also implements IStream. The implementation is not very complicated, it just delegates the IStream methods to the base class, but it involves some native pointer manipulation. Once we have a stream, we need to build the encoder for the output format, which could be anything that WIC supports. For web thumbnails, our only reasonable options are PNG and JPEG. I explored PNG because it’s a lossless format, and because WIC does support PNG compression. That compression is not very efficient though and JPEG offers good quality with much smaller file sizes. On the web, it matters. I found the best PNG compression option (adaptive) to give files that are about twice as big as 100%-quality JPEG (an absurd setting), 4.5 times bigger than 95%-quality JPEG and 7 times larger than 85%-quality JPEG, which is more than acceptable quality. As a consequence, we’ll use JPEG. The JPEG encoder can be prepared as follows: var encoder = factory.CreateEncoder( Consts.GUID_ContainerFormatJpeg, null); encoder.Initialize(outputStream, WICBitmapEncoderCacheOption.WICBitmapEncoderNoCache); The next operation is to create the output frame: IWICBitmapFrameEncode outputFrame; var arg = new IPropertyBag2[1]; encoder.CreateNewFrame(out outputFrame, arg); Notice that we are passing in a property bag. This is where we’re going to specify our only parameter for encoding, the JPEG quality setting: var propBag = arg[0]; var propertyBagOption = new PROPBAG2[1]; propertyBagOption[0].pstrName = "ImageQuality"; propBag.Write(1, propertyBagOption, new object[] { 0.85F }); outputFrame.Initialize(propBag); We can then set the resolution for the thumbnail to be 96, something we weren’t able to do with WPF and had to hack around: outputFrame.SetResolution(96, 96); Next, we set the size of the output frame and create a scaler from the input frame and the computed dimensions of the target thumbnail: outputFrame.SetSize(thumbWidth, thumbHeight); var scaler = factory.CreateBitmapScaler(); scaler.Initialize(frame, thumbWidth, thumbHeight, WICBitmapInterpolationMode.WICBitmapInterpolationModeFant); The scaler is using the Fant method, which I think is the best looking one even if it seems a little softer than cubic (zoomed here to better show the defects): Cubic Fant Linear Nearest neighbor We can write the source image to the output frame through the scaler: outputFrame.WriteSource(scaler, new WICRect { X = 0, Y = 0, Width = (int)thumbWidth, Height = (int)thumbHeight }); And finally we commit the pipeline that we built and get the byte array for the thumbnail out of our memory stream: outputFrame.Commit(); encoder.Commit(); var outputArray = outputStream.ToArray(); outputStream.Close(); That byte array can then be sent to the output stream and to the cache file. Once we’ve gone through this exercise, it’s only natural to wonder whether it was worth the trouble. I ran this method, as well as GDI and WPF resizing over thirty twelve megapixel images for JPEG qualities between 70% and 100% and measured the file size and time to resize. Here are the results: Size of resized images   Time to resize thirty 12 megapixel images Not much to see on the size graph: sizes from WPF and WIC are equivalent, which is hardly surprising as WPF calls into WIC. There is just an anomaly for 75% for WPF that I noted in my previous article and that disappears when using WIC directly. But overall, using WPF or WIC over GDI represents a slight win in file size. The time to resize is more interesting. WPF and WIC get similar times although WIC seems to always be a little faster. Not surprising considering WPF is using WIC. The margin of error on this results is probably fairly close to the time difference. As we already knew, the time to resize does not depend on the quality level, only the size does. This means that the only decision you have to make here is size versus visual quality. This third approach to server-side image resizing on ASP.NET seems to converge on the fastest possible one. We have marginally better performance than WPF, but with some additional peace of mind that this approach is sanctioned for server-side usage by the Windows Imaging team. It still doesn’t work in medium trust. That is a problem and shows the way for future server-friendly managed wrappers around WIC. The sample code for this article can be downloaded from: http://weblogs.asp.net/blogs/bleroy/Samples/WicResize.zip The benchmark code can be found here (you’ll need to add your own images to the Images directory and then add those to the project, with content and copy if newer in the properties of the files in the solution explorer): http://weblogs.asp.net/blogs/bleroy/Samples/WicWpfGdiImageResizeBenchmark.zip WIC tools can be downloaded from: http://code.msdn.microsoft.com/wictools To conclude, here are some of the resized thumbnails at 85% fant:

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• The fastest way to resize images from ASP.NET. And it’s (more) supported-ish.

  - by Latest Microsoft Blogs

  I’ve shown before how to resize images using GDI , which is fairly common but is explicitly unsupported because we know of very real problems that this can cause. Still, many sites still use that method because those problems are fairly rare, and because Read More......(read more)

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• Two Introductory VS2010 Entity Framework Videos on Pluralsight on Demand

  These are the first two. I’ve got more coming! ...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Solving Null Entity Problems with JPA Data Controls in PS1

  - by shay.shmeltzer

  Turns out there is a slight bug that seems to prevent you from doing interactions (update, scroll) with the results of a JPA named query that you dropped on a page using ADF Binding. People are running into this when they are doing the EJB tutorial on OTN for example. The problem is that the way the binding is set up for you automatically doesn't allow you to actually access the iterator set of records to do follow up operations. When I last checked this was solved in the next release of JDeveloper, but in the meantime there is a quick simple way to resolve the issue by changing the refresh condition of the oiterator in your page binding. Here is a little demo that shows the problem and the solution:

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• When should a bullet texture be loaded in XNA?

  - by Bill

  I'm making a SpaceWar!-esque game using XNA. I want to limit my ships to 5 active bullets at any time. I have a Bullet DrawableGameComponent and a Ship DrawableGameComponent. My Ship has an array of 5 Bullet. What is the best way to manage the Bullet textures? Specifically, when should I be calling LoadTexture? Right now, my solution is to populate the Bullet array in the Ship's constructor, with LoadTexture being called in the Bullet constructor. The Bullet objects will be disabled/not visible except when they are active. Does the texture really need to be loaded once for each individual instance of the bullet object? This seems like a very processor-intensive operation. Note: This is a small-scale project, so I'm OK with not implementing a huge texture-management framework since there won't be more than half a dozen or so in the entire game. I'd still like to hear about scalable solutions for future applications, though.

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• What are the cons of using DrawableGameComponent for every instance of a game object?

  - by Kensai

  I've read in many places that DrawableGameComponents should be saved for things like "levels" or some kind of managers instead of using them, for example, for characters or tiles (Like this guy says here). But I don't understand why this is so. I read this post and it made a lot of sense to me, but these are the minority. I usually wouldn't pay too much attention to things like these, but in this case I would like to know why the apparent majority believes this is not the way to go. Maybe I'm missing something.

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• Load order in XNA?

  - by marc wellman

  I am wondering whether the is a mechanism to manually control the call-order of void Game.LoadContent() as it is the case with void Game.Draw(GameTime gt) by setting int DrawableGameComponent.DrawOrder ? except the order that results from adding components to the Game.Components container and maybe there exists something similar with Game.Update(GameTime gt) ? UPDATE To exemplify my issue consider you have several game components which do depends to each other regarding their instantiation. All are inherited from DrawableGameComponent. Now suppose that in one of these components you are loading a Model from the games content pipeline and add it to some static container in order to provide access to it for other game components. public override LoadContent() { // ... Model m = _contentManager.Load<Model>(@"content/myModel"); // GameComponents is a static class with an accessible list where game components reside. GameComponents.AddCompnent(m); // ... } Now it's easy to imagine that this components load method has to precede other game components that do want to access the model m in their own load method.

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• OOP - Composition, Components and Composites Example?

  - by coder3

  I've been reading a bit about OOP in relation to Composition, Components and Composites. I believe I understand the fundamental principle (not sure). Can some one please provide a code example of a person or car (both have many properties) using Composition, Components and Composites. I think seeing it in code would clear up the confusion I have regarding this pattern. Preferably in Java or PHP - many thanks!

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• Shows how to use AutocompleteExtender to populate subjects and databind quotations via Entity Framew

  This article will focus on a database of famous quotations that I"ve pared down to a downloadable size for a demo, and how to wire up the AJAX Toolkit autocomplete extender to a textbox that is used to typeahead a Subject. When the ClientItemSelected event fires, the Display button Click is invoked, and this causes an EF query to display the matching quotes in a DataList.  read moreBy Peter BrombergDid you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Shows how to use AutocompleteExtender to populate subjects and databind quotations via Entity Framew

  This article will focus on a database of famous quotations that I"ve pared down to a downloadable size for a demo, and how to wire up the AJAX Toolkit autocomplete extender to a textbox that is used to typeahead a Subject. When the ClientItemSelected event fires, the Display button Click is invoked, and this causes an EF query to display the matching quotes in a DataList.  read moreBy Peter BrombergDid you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Sprites, Primitives and logic entity as structs

  - by Jeffrey

  I'm wondering would it be considered acceptable: The window class is responsible for drawing data, so it will have a method: Window::draw(const Sprite&); Window::draw(const Rect&); Window::draw(const Triangle&); Window::draw(const Circle&); and all those primitives + sprites would be just public struct. For example Sprite: struct Sprite { float x, y; // center float origin_x, origin_y; float width, height; float rotation; float scaling; GLuint texture; Sprite(float w, float h); Sprite(float w, float h, float a, float b); void useTexture(std::string file); void setOrigin(float a, float b); void move(float a, float b); // relative move void moveTo(float a, float b); // absolute move void rotate(float a); // relative rotation void rotateTo(float a); // absolute rotation void rotationReset(); void scale(float a); // relative scaling void scaleTo(float a); // absolute scaling void scaleReset(); }; So instead of having each primitive to call their draw() function, which is a little bit off topic for their object, I let the Window class handle all the OpenGL stuff and manipulate them as simple objects that will be drawn later on. Is this pattern used? Does it have any cons against it's primitives-draw-themself pattern? Are there any other related patterns?

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• I need to move an entity to the mouse location after i rightclick

  - by I.Hristov

  Well I've read the related questions-answers but still cant find a way to move my champion to the mouse position after a right-button mouse-click. I use this code at the top: float speed = (float)1/3; And this is in my void Update: //check if right mouse button is clicked if (mouse.RightButton == ButtonState.Released && previousButtonState == ButtonState.Pressed) { // gets the position of the mouse in mousePosition mousePosition = new Vector2(mouse.X, mouse.Y); //gets the current position of champion (the drawRectangle) currentChampionPosition = new Vector2(drawRectangle.X, drawRectangle.Y); // move champion to mouse position: //handles the case when the mouse position is really close to current position if (Math.Abs(currentChampionPosition.X - mousePosition.X) <= speed && Math.Abs(currentChampionPosition.Y - mousePosition.Y) <= speed) { drawRectangle.X = (int)mousePosition.X; drawRectangle.Y = (int)mousePosition.Y; } else if (currentChampionPosition != mousePosition) { drawRectangle.X += (int)((mousePosition.X - currentChampionPosition.X) * speed); drawRectangle.Y += (int)((mousePosition.Y - currentChampionPosition.Y) * speed); } } previousButtonState = mouse.RightButton; What that code does at the moment is on a click it brings the sprite 1/3 of the distance to the mouse but only once. How do I make it move consistently all the time? It seems I am not updating the sprite at all. EDIT I added the Vector2 as Nick said and with speed changed to 50 it should be OK. I tried it with if ButtonState.Pressed and it works while pressing the button. Thanks. However I wanted it to start moving when single mouse clicked. It should be moving until reaches the mousePosition. The Edit of Nick's post says to create another Vector2, But I already have the one called mousePosition. Not sure how to use another one. //gets a Vector2 direction to move *by Nick Wilson Vector2 direction = mousePosition - currentChampionPosition; //make the direction vector a unit vector direction.Normalize(); //multiply with speed (number of pixels) direction *= speed; // move champion to mouse position if (currentChampionPosition != mousePosition) { drawRectangle.X += (int)(direction.X); drawRectangle.Y += (int)(direction.Y); } } previousButtonState = mouse.RightButton;

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• The provider did not return a ProviderManifestToken string Entity Framework

  - by PearlFactory

  Moved from Home to work and went to fire up my project and after long pause "The provider did not return a ProviderManifestToken string" or even More Abscure ProviderIncompatable Exception Now after 20 mins of chasing my tail re different ver of EntityFramework 4.1 vs 4.2...blahblahblah Look inside at the inner exception A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible DOH!!!! Or a clean translation is that it cant find SQL or is offline or not running. SO check the power is on/Service running or as in my case Edit web.config & change back to Work SQL box   Hope you dont have this pain as the default errors @ the moment suck balls in the EntityFramework 4.XX releases   Cheers

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