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• Employee Info Starter Kit: Project Mission

  - by Mohammad Ashraful Alam

  Employee Info Starter Kit is an open source ASP.NET project template that is intended to address different types of real world challenges faced by web application developers when performing common CRUD operations. Using a single database table ‘Employee’, it illustrates how to utilize Microsoft ASP.NET 4.0, Entity Framework 4.0 and Visual Studio 2010 effectively in that context. Employee Info Starter Kit is highly influenced by the concept ‘Pareto Principle’ or 80-20 rule. where it is targeted to enable a web developer to gain 80% productivity with 20% of effort with respect to learning curve and production. User Stories The user end functionalities of this starter kit are pretty simple and straight forward that are focused in to perform CRUD operation on employee records as described below. Creating a new employee record Read existing employee record Update an existing employee record Delete existing employee records Key Technology Areas ASP.NET 4.0 Entity Framework 4.0 T-4 Template Visual Studio 2010 Architectural Objective There is no universal architecture which can be considered as the best for all sorts of applications around the world. Based on requirements, constraints, environment, application architecture can differ from one to another. Trade-off factors are one of the important considerations while deciding a particular architectural solution. Employee Info Starter Kit is highly influenced by the concept ‘Pareto Principle’ or 80-20 rule, where it is targeted to enable a web developer to gain 80% productivity with 20% of effort with respect to learning curve and production. “Productivity” as the architectural objective typically also includes other trade-off factors as well as, such as testability, flexibility, performance etc. Fortunately Microsoft .NET Framework 4.0 and Visual Studio 2010 includes lots of great features that have been implemented cleverly in this project to reduce these trade-off factors in the minimum level. Why Employee Info Starter Kit is Not a Framework? Application frameworks are really great for productivity, some of which are really unavoidable in this modern age. However relying too many frameworks may overkill a project, as frameworks are typically designed to serve wide range of different usage and are less customizable or editable. On the other hand having implementation patterns can be useful for developers, as it enables them to adjust application on demand. Employee Info Starter Kit provides hundreds of “connected” snippets and implementation patterns to demonstrate problem solutions in actual production environment. It also includes Visual Studio T-4 templates that generate thousands lines of data access and business logic layer repetitive codes in literally few seconds on the fly, which are fully mock testable due to language support for partial methods and latest support for mock testing in Entity Framework. Why Employee Info Starter Kit is Different than Other Open-source Web Applications? Software development is one of the rapid growing industries around the globe, where the technology is being updated very frequently to adapt greater challenges over time. There are literally thousands of community web sites, blogs and forums that are dedicated to provide support to adapt new technologies. While some are really great to enable learning new technologies quickly, in most cases they are either too “simple and brief” to be used in real world scenarios or too “complex and detailed” which are typically focused to achieve a product goal (such as CMS, e-Commerce etc) from "end user" perspective and have a long duration learning curve with respect to the corresponding technology. Employee Info Starter Kit, as a web project, is basically "developer" oriented which actually considers a hybrid approach as “simple and detailed”, where a simple domain has been considered to intentionally illustrate most of the architectural and implementation challenges faced by web application developers so that anyone can dive into deep into the corresponding new technology or concept quickly. Roadmap Since its first release by 2008 in MSDN Code Gallery, Employee Info Starter Kit gained a huge popularity in ASP.NET community and had 1, 50,000+ downloads afterwards. Being encouraged with this great response, we have a strong commitment for the community to provide support for it with respect to latest technologies continuously. Currently hosted in Codeplex, this community driven project is planned to have a wide range of individual editions, each of which will be focused on a selected application architecture, framework or platform, such as ASP.NET Webform, ASP.NET Dynamic Data, ASP.NET MVC, jQuery Ajax (RIA), Silverlight (RIA), Azure Service Platform (Cloud), Visual Studio Automated Test etc. See here for full list of current and future editions.

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• Unit Testing DateTime – The Crazy Way

  - by João Angelo

  We all know that the process of unit testing code that depends on DateTime, particularly the current time provided through the static properties (Now, UtcNow and Today), it’s a PITA. If you go ask how to unit test DateTime.Now on stackoverflow I’ll bet that you’ll get two kind of answers: Encapsulate the current time in your own interface and use a standard mocking framework; Pull out the big guns like Typemock Isolator, JustMock or Microsoft Moles/Fakes and mock the static property directly. Now each alternative has is pros and cons and I would have to say that I glean more to the second approach because the first adds a layer of abstraction just for the sake of testability. However, the second approach depends on commercial tools that not every shop wants to buy or in the not so friendly Microsoft Moles. (Sidenote: Moles is now named Fakes and it will ship with VS 2012) This tends to leave people without an acceptable and simple solution so after reading another of these types of questions in SO I came up with yet another alternative, one based on the first alternative that I presented here but tries really hard to not get in your way with yet another layer of abstraction. So, without further dues, I present you, the Tardis. The Tardis is single section of conditionally compiled code that overrides the meaning of the DateTime expression inside a single class. You still get the normal coding experience of using DateTime all over the place, but in a DEBUG compilation your tests will be able to mock every static method or property of the DateTime class. An example follows, while the full Tardis code can be downloaded from GitHub: using System; using NSubstitute; using NUnit.Framework; using Tardis; public class Example { public Example() : this(string.Empty) { } public Example(string title) { #if DEBUG this.DateTime = DateTimeProvider.Default; this.Initialize(title); } internal IDateTimeProvider DateTime { get; set; } internal Example(string title, IDateTimeProvider provider) { this.DateTime = provider; #endif this.Initialize(title); } private void Initialize(string title) { this.Title = title; this.CreatedAt = DateTime.UtcNow; } private string title; public string Title { get { return this.title; } set { this.title = value; this.UpdatedAt = DateTime.UtcNow; } } public DateTime CreatedAt { get; private set; } public DateTime UpdatedAt { get; private set; } } public class TExample { public void T001() { // Arrange var tardis = Substitute.For<IDateTimeProvider>(); tardis.UtcNow.Returns(new DateTime(2000, 1, 1, 6, 6, 6)); // Act var sut = new Example("Title", tardis); // Assert Assert.That(sut.CreatedAt, Is.EqualTo(tardis.UtcNow)); } public void T002() { // Arrange var tardis = Substitute.For<IDateTimeProvider>(); var sut = new Example("Title", tardis); tardis.UtcNow.Returns(new DateTime(2000, 1, 1, 6, 6, 6)); // Act sut.Title = "Updated"; // Assert Assert.That(sut.UpdatedAt, Is.EqualTo(tardis.UtcNow)); } } This approach is also suitable for other similar classes with commonly used static methods or properties like the ConfigurationManager class.

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• Dependency Injection Introduction

  - by MarkPearl

  I recently was going over a great book called “Dependency Injection in .Net” by Mark Seeman. So far I have really enjoyed the book and would recommend anyone looking to get into DI to give it a read. Today I thought I would blog about the first example Mark gives in his book to illustrate some of the benefits that DI provides. The ones he lists are Late binding Extensibility Parallel Development Maintainability Testability To illustrate some of these benefits he gives a HelloWorld example using DI that illustrates some of the basic principles. It goes something like this… class Program { static void Main(string[] args) { var writer = new ConsoleMessageWriter(); var salutation = new Salutation(writer); salutation.Exclaim(); Console.ReadLine(); } } public interface IMessageWriter { void Write(string message); } public class ConsoleMessageWriter : IMessageWriter { public void Write(string message) { Console.WriteLine(message); } } public class Salutation { private readonly IMessageWriter _writer; public Salutation(IMessageWriter writer) { _writer = writer; } public void Exclaim() { _writer.Write("Hello World"); } }   If you had asked me a few years ago if I had thought this was a good approach to solving the HelloWorld problem I would have resounded “No”. How could the above be better than the following…. class Program { static void Main(string[] args) { Console.WriteLine("Hello World"); Console.ReadLine(); } }  Today, my mind-set has changed because of the pain of past programs. So often we can look at a small snippet of code and make judgements when we need to keep in mind that we will most probably be implementing these patterns in projects with hundreds of thousands of lines of code and in projects that we have tests that we don’t want to break and that’s where the first solution outshines the latter. Let’s see if the first example achieves some of the outcomes that were listed as benefits of DI. Could I test the first solution easily? Yes… We could write something like the following using NUnit and RhinoMocks… [TestFixture] public class SalutationTests { [Test] public void ExclaimWillWriteCorrectMessageToMessageWriter() { var writerMock = MockRepository.GenerateMock<IMessageWriter>(); var sut = new Salutation(writerMock); sut.Exclaim(); writerMock.AssertWasCalled(x => x.Write("Hello World")); } }   This would test the existing code fine. Let’s say we then wanted to extend the original solution so that we had a secure message writer. We could write a class like the following… public class SecureMessageWriter : IMessageWriter { private readonly IMessageWriter _writer; private readonly string _secretPassword; public SecureMessageWriter(IMessageWriter writer, string secretPassword) { _writer = writer; _secretPassword = secretPassword; } public void Write(string message) { if (_secretPassword == "Mark") { _writer.Write(message); } else { _writer.Write("Unauthenticated"); } } }   And then extend our implementation of the program as follows… class Program { static void Main(string[] args) { var writer = new SecureMessageWriter(new ConsoleMessageWriter(), "Mark"); var salutation = new Salutation(writer); salutation.Exclaim(); Console.ReadLine(); } }   Our application has now been successfully extended and yet we did very little code change. In addition, our existing tests did not break and we would just need add tests for the extended functionality. Would this approach allow parallel development? Well, I am in two camps on parallel development but with some planning ahead of time it would allow for it as you would simply need to decide on the interface signature and could then have teams develop different sections programming to that interface. So,this was really just a quick intro to some of the basic concepts of DI that Mark introduces very successfully in his book. I am hoping to blog about this further as I continue through the book to list some of the more complex implementations of containers.

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• What makes static initialization functions good, bad, or otherwise?

  - by Richard Levasseur

  Suppose you had code like this: _READERS = None _WRITERS = None def Init(num_readers, reader_params, num_writers, writer_params, ...args...): ...logic... _READERS = new ReaderPool(num_readers, reader_params) _WRITERS = new WriterPool(num_writers, writer_params) ...more logic... class Doer: def __init__(...args...): ... def Read(self, ...args...): c = _READERS.get() try: ...work with conn finally: _READERS.put(c) def Writer(...): ...similar to Read()... To me, this is a bad pattern to follow, some cons: Doers can be created without its preconditions being satisfied The code isn't easily testable because ConnPool can't be directly mocked out. Init has to be called right the first time. If its changed so it can be called multiple times, extra logic has to be added to check if variables are already defined, and lots of NULL values have to be passed around to skip re-initializing. In the event of threads, the above becomes more complicated by adding locking Globals aren't being used to communicate state (which isn't strictly bad, but a code smell) On the other hand, some pros: its very convenient to call Init(5, "user/pass", 2, "user/pass") It simple and "clean" Personally, I think the cons outweigh the pros, that is, testability and assured preconditions outweigh simplicity and convenience.

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• passive view and display logic

  - by genesys

  Hi! In MVC and MVP and similar patterns there's often the approach of the "passive view" which is as stupid as possible. This should facilitate unit testing and create a clearer separation of view and model. I know that those patterns come in very different flavours and especially the understanding of MVP seems to differ from article to article. Therefore my question is not "how do i implement this pattern correctly". I want to improve view and model separation and go for better testability of the application. Therefore i'd like to go for a passive view. But my question is, where would you put logic that is clearly only view related? like a textviewer should scroll the text when the scrollbar is moved. would you put the logic for this into the Presenter? Let's say the textviewer has some extended functionality. like setting markings on textpassages. The logic for this makes clearly sense to be put into the Presenter. However, if it is mixed with all the 'direct' logic of the view (like scrolling the text) the Presenter could become very big, which is also not really a nice design. So my question is where to put display related logic of a passive view and what functionallity to mix in the Presenter. Thanks!

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• Dependency Injection and decoupling of software layers

  - by cs31415

  I am trying to implement Dependency Injection to make my app tester friendly. I have a rather basic doubt. Data layer uses SqlConnection object to connect to a SQL server database. SqlConnection object is a dependency for data access layer. In accordance with the laws of dependency injection, we must not new() dependent objects, but rather accept them through constructor arguments. Not wanting to upset the DI gods, I dutifully create a constructor in my DAL that takes in SqlConnection. Business layer calls DAL. Business layer must therefore, pass in SqlConnection. Presentation layer calls Business layer. Hence it too, must pass in SqlConnection to business layer. This is great for class isolation and testability. But didn't we just couple the UI and Business layers to a specific implementation of the data layer which happens to use a relational database? Why do the Presentation and Business layers need to know that the underlying data store is SQL? What if the app needs to support multiple data sources other than SQL server (such as XML files, Comma delimited files etc.) Furthermore, what if I add another object upon which my data layer is dependent on (say, a second database). Now, I have to modify the upper layers to pass in this new object. How can I avoid this merry-go-round and reap all the benefits of DI without the pain?

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• How would the 'Model' in a Rails-type webapp be implemented in a functional programming langauge?

  - by ceptorial

  In MVC web development frameworks such as Ruby on Rails, Django, and CakePHP, HTTP requests are routed to controllers, which fetch objects which are usually persisted to a backend database store. These objects represent things like users, blog posts, etc., and often contain logic within their methods for permissions, fetching and/or mutating other objects, validation, etc. These frameworks are all very much object oriented. I've been reading up recently on functional programming and it seems to tout tremendous benefits such as testability, conciseness, modularity, etc. However most of the examples I've seen for functional programming implement trivial functionality like quicksort or the fibonnacci sequence, not complex webapps. I've looked at a few 'functional' web frameworks, and they all seem to implement the view and controller just fine, but largely skip over the whole 'model' and 'persistence' part. (I'm talking more about frameworks like Compojure which are supposed to be purely functional, versus something Lift which conveniently seems to use the OO part of Scala for the model -- but correct me if I'm wrong here.) I haven't seen a good explanation of how functional programming can be used to provide the metaphor that OO programming provides, i.e. tables map to objects, and objects can have methods which provide powerful, encapsulated logic such as permissioning and validation. Also the whole concept of using SQL queries to persist data seems to violate the whole 'side effects' concept. Could someone provide an explanation of how the 'model' layer would be implemented in a functionally programmed web framework?

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• Testing a Gui-heavy WPF application.

  - by Hamish Grubijan

  We (my colleagues) have a messy 12 y.o. mature app that is GUI-based, and the current plan is to add new dialogs & other GUI in WPF, as well as replace some of the older dialogs in WPF as well. At the same time we wish to be able to test that Monster - GUI automation in a maintainable way. Some challenges: The application is massive. It constantly gains new features. It is being changed around (bug fixes, patches). It has a back end, and a layer in-between. The state of it can get out of whack if you beat it to death. What we want is: Some tool that can automate testing of WPF. auto-discovery of what the inputs and the outputs of the dialog are. An old test should still work if you add a label that does nothing. It should fail, however, if you remove a necessary text field. It would be very nice if the test suite was easy to maintain, if it ran and did not break most of the time. Every new dialog should be created with testability in mind. At this point I do not know exactly what I want, so I am marking this as a community wiki. If having to test a huge GUI-based app rings the bell (even if not in WPF), then please share your good, bad and ugly experiences here.

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• Decoupling the view, presentation and ASP.NET Web Forms

  - by John Leidegren

  I have an ASP.NET Web Forms page which the presenter needs to populate with controls. This interaction is somewhat sensitive to the page-life cycle and I was wondering if there's a trick to it, that I don't know about. I wanna be practical about the whole thing but not compromise testability. Currently I have this: public interface ISomeContract { void InstantiateIn(System.Web.UI.Control container); } This contract has a dependency on System.Web.UI.Control and I need that to be able to do things with the ASP.NET Web Forms programming model. But neither the view nor the presenter may have knowledge about ASP.NET server controls. How do I get around this? How can I work with the ASP.NET Web Forms programming model in my concrete views without taking a System.Web.UI.Control dependency in my contract assemblies? To clarify things a bit, this type of interface is all about UI composition (using MEF). It's known through-out the framework but it's really only called from within the concrete view. The concrete view is still the only thing that knows about ASP.NET Web Forms. However those public methods that say InstantiateIn(System.Web.UI.Control) exists in my contract assemblies and that implies a dependency on ASP.NET Web Forms. I've been thinking about some double dispatch mechanism or even visitor pattern to try and work around this.

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• asp.net mvc stand alone ascx control how do i link (css and js) most efficiently

  - by Julian

  Hi, I need some advice. I have developed some asp.net mvc web pages. Each page has a master and some ascx controls (between 2 - 6) embedded into it a js and css file. Up to now every thing was fine. In order to improve modularity, flexibility and testability the ascx's are now expected to be able to work as stand alone controls. (Each ascx has also got its own css and js files in some cases it has another control inside it) In order to meet this requirement we call the controller with the relevant parameters and it returns the ascx (partial) directly to the browser without all of the other parts of the original page . In order to get it to display correctly (css) and act correctly (js/jquery) all of the relevant files need to be added (as links or scripts eg. href="<%= ResolveUrl(styleSheet)%>") to the user control. This is "contradicting" the concept of positioning the files at the most logical place (could be the master page for example). How can I overcome this problem? Keep in mind that this is relevant for each "control" ascx file. Any thoughts will be appreciated.

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• Simple-Talk development: a quick history lesson

  - by Michael Williamson

  Up until a few months ago, Simple-Talk ran on a pure .NET stack, with IIS as the web server and SQL Server as the database. Unfortunately, the platform for the site hadn’t quite gotten the love and attention it deserved. On the one hand, in the words of our esteemed editor Tony “I’d consider the current platform to be a “success”; it cost $10K, has lasted for 6 years, was finished, end to end in 6 months, and although we moan about it has got us quite a long way.” On the other hand, it was becoming increasingly clear that it needed some serious work. Among other issues, we had authors that wouldn’t blog because our current blogging platform, Community Server, was too painful for them to use. Forgetting about Simple-Talk for a moment, if you ask somebody what blogging platform they’d choose, the odds are they’d say WordPress. Regardless of its technical merits, it’s probably the most popular blogging platform, and it certainly seemed easier to use than Community Server. The issue was that WordPress is normally hosted on a Linux stack running PHP, Apache and MySQL — quite a difference from our Microsoft technology stack. We certainly didn’t want to rewrite the entire site — we just wanted a better blogging platform, with the rest of the existing, legacy site left as is. At a very high level, Simple-Talk’s technical design was originally very straightforward: when your browser sends an HTTP request to Simple-Talk, IIS (the web server) takes the request, does some work, and sends back a response. In order to keep the legacy site running, except with WordPress running the blogs, a different design is called for. We now use nginx as a reverse-proxy, which can then delegate requests to the appropriate application: So, when your browser sends a request to Simple-Talk, nginx takes that request and checks which part of the site you’re trying to access. Most of the time, it just passes the request along to IIS, which can then respond in much the same way it always has. However, if your request is for the blogs, then nginx delegates the request to WordPress. Unfortunately, as simple as that diagram looks, it hides an awful lot of complexity. In particular, the legacy site running on IIS was made up of four .NET applications. I’ve already mentioned one of these applications, Community Server, which handled the old blogs as well as managing membership and the forums. We have a couple of other applications to manage both our newsletters and our articles, and our own custom application to do some of the rendering on the site, such as the front page and the articles. When I say that it was made up of four .NET applications, this might conjure up an image in your mind of how they fit together: You might imagine four .NET applications, each with their own database, communicating over well-defined APIs. Sadly, reality was a little disappointing: We had four .NET applications that all ran on the same database. Worse still, there were many queries that happily joined across tables from multiple applications, meaning that each application was heavily dependent on the exact data schema that each other application used. Add to this that many of the queries were at least dozens of lines long, and practically identical to other queries except in a few key spots, and we can see that attempting to replace one component of the system would be more than a little tricky. However, the problems with the old system do give us a good place to start thinking about desirable qualities from any changes to the platform. Specifically: Maintainability — the tight coupling between each .NET application made it difficult to update any one application without also having to make changes elsewhere Replaceability — the tight coupling also meant that replacing one component wouldn’t be straightforward, especially if it wasn’t on a similar Microsoft stack. We’d like to be able to replace different parts without having to modify the existing codebase extensively Reusability — we’d like to be able to combine the different pieces of the system in different ways for different sites Repeatable deployments — rather than having to deploy the site manually with a long list of instructions, we should be able to deploy the entire site with a single command, allowing you to create a new instance of the site easily whether on production, staging servers, test servers or your own local machine Testability — if we can deploy the site with a single command, and each part of the site is no longer dependent on the specifics of how every other part of the site works, we can begin to run automated tests against the site, and against individual parts, both to prevent regressions and to do a little test-driven development In the next part, I’ll describe the high-level architecture we now have that hopefully brings us a little closer to these five traits.

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• Best practice to handle Parent Form Child Form relation using Presentation Model

  - by Rajarshi

  According to Presentation Model notes by Martin Fowler and also on MSDN documentation about Presentation Model, it is explained that the Presentation Model Class should be unaware of the UI class and similarly Business Model Class should be unaware of the Presentation Model class. The UI should databind extensively to the Presentation Model, the Presentation Model in turn will co-ordinate with one or more Domain/Business Model objects to get the job done. The Presentation Model basically presents the Domain Model data in a way to facilitate maximum data binding in UI, allowing the UI take as less decisions as possible and thus increase testability of Presentation behaviours. This also makes the presentation model class generic, i.e. agnostic of any particular UI technology. Now, consider there is a List form (say CustomerList) and there is another Root form (say Customer) and there is a Use Case of allowing to Edit a Customer from the CustomerList form on a button click. For simplicity of discussion, consider that some actions took place when Customer List is opened from menu (i.e. Customer menu clicked) and the Customer List has been shown from the Menu click event. Now as per the above Use Case, I need to open the Customer Root UI (single Customer) from the Customer List. How do I do that? Build necessary objects (BusinessModel, PresentationModel, UI) in click event of Edit button and call CustomerEdit UI from there? Build the CustomerEdit UI from Presentation Model Class and show UI from presentation model? this can be done in any of the two ways below - a. Create objects in the following sequence DomainModel-PresentationModel-UIForm b. Use Unity.Resolve(); Either ways, Presentation Model is violated as the P model now has to the refer the concrete UI assembly, where CustomerEdit is located. Also the P Model has to refer and use a WinForm directly making it less UI technology agnostic. Even though the violations are in theory and can be ignored, I would still seek the community's opinion about whether I am going wrong direction. Please suggest if there's a better way to call the Child Form from the List (Parent) Form. Rajarshi

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• Is MVVM pointless?

  - by joebeazelman

  Is orthodox MVVM implementation pointless? I am creating a new application and I considered Windows Forms and WPF. I chose WPF because it's future-proof and offer lots of flexibility. There is less code and easier to make significant changes to your UI using XAML. Since the choice for WPF is obvious, I figured that I may as well go all the way by using MVVM as my application architecture since it offers blendability, separation concerns and unit testability. Theoretically, it seems beautiful like the holy grail of UI programming. This brief adventure; however, has turned into a real headache. As expected in practice, I’m finding that I’ve traded one problem for another. I tend to be an obsessive programmer in that I want to do things the right way so that I can get the right results and possibly become a better programmer. The MVVM pattern just flunked my test on productivity and has just turned into a big yucky hack! The clear case in point is adding support for a Modal dialog box. The correct way is to put up a dialog box and tie it to a view model. Getting this to work is difficult. In order to benefit from the MVVM pattern, you have to distribute code in several places throughout the layers of your application. You also have to use esoteric programming constructs like templates and lamba expressions. Stuff that makes you stare at the screen scratching your head. This makes maintenance and debugging a nightmare waiting to happen as I recently discovered. I had an about box working fine until I got an exception the second time I invoked it, saying that it couldn’t show the dialog box again once it is closed. I had to add an event handler for the close functionality to the dialog window, another one in the IDialogView implementation of it and finally another in the IDialogViewModel. I thought MVVM would save us from such extravagant hackery! There are several folks out there with competing solutions to this problem and they are all hacks and don’t provide a clean, easily reusable, elegant solution. Most of the MVVM toolkits gloss over dialogs and when they do address them, they are just alert boxes that don’t require custom interfaces or view models. I’m planning on giving up on the MVVM view pattern, at least its orthodox implementation of it. What do you think? Has it been worth the trouble for you if you had any? Am I just a incompetent programmer or does MVVM not what it's hyped up to be?

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• Correct way of using/testing event service in Eclipse E4 RCP

  - by Thorsten Beck

  Allow me to pose two coupled questions that might boil down to one about good application design ;-) What is the best practice for using event based communication in an e4 RCP application? How can I write simple unit tests (using JUnit) for classes that send/receive events using dependency injection and IEventBroker ? Let’s be more concrete: say I am developing an Eclipse e4 RCP application consisting of several plugins that need to communicate. For communication I want to use the event service provided by org.eclipse.e4.core.services.events.IEventBroker so my plugins stay loosely coupled. I use dependency injection to inject the event broker to a class that dispatches events: @Inject static IEventBroker broker; private void sendEvent() { broker.post(MyEventConstants.SOME_EVENT, payload) } On the receiver side, I have a method like: @Inject @Optional private void receiveEvent(@UIEventTopic(MyEventConstants.SOME_EVENT) Object payload) Now the questions: In order for IEventBroker to be successfully injected, my class needs access to the current IEclipseContext. Most of my classes using the event service are not referenced by the e4 application model, so I have to manually inject the context on instantiation using e.g. ContextInjectionFactory.inject(myEventSendingObject, context); This approach works but I find myself passing around a lot of context to wherever I use the event service. Is this really the correct approach to event based communication across an E4 application? how can I easily write JUnit tests for a class that uses the event service (either as a sender or receiver)? Obviously, none of the above annotations work in isolation since there is no context available. I understand everyone’s convinced that dependency injection simplifies testability. But does this also apply to injecting services like the IEventBroker? This article describes creation of your own IEclipseContext to include the process of DI in tests. Not sure if this could resolve my 2nd issue but I also hesitate running all my tests as JUnit Plug-in tests as it appears impractible to fire up the PDE for each unit test. Maybe I just misunderstand the approach. This article speaks about “simply mocking IEventBroker”. Yes, that would be great! Unfortunately, I couldn’t find any information on how this can be achieved. All this makes me wonder whether I am still on a "good path" or if this is already a case of bad design? And if so, how would you go about redesigning? Move all event related actions to dedicated event sender/receiver classes or a dedicated plugin?

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• How to implement a caching model without violating MVC pattern?

  - by RPM1984

  Hi Guys, I have an ASP.NET MVC 3 (Razor) Web Application, with a particular page which is highly database intensive, and user experience is of the upmost priority. Thus, i am introducing caching on this particular page. I'm trying to figure out a way to implement this caching pattern whilst keeping my controller thin, like it currently is without caching: public PartialViewResult GetLocationStuff(SearchPreferences searchPreferences) { var results = _locationService.FindStuffByCriteria(searchPreferences); return PartialView("SearchResults", results); } As you can see, the controller is very thin, as it should be. It doesn't care about how/where it is getting it's info from - that is the job of the service. A couple of notes on the flow of control: Controllers get DI'ed a particular Service, depending on it's area. In this example, this controller get's a LocationService Services call through to an IQueryable<T> Repository and materialize results into T or ICollection<T>. How i want to implement caching: I can't use Output Caching - for a few reasons. First of all, this action method is invoked from the client-side (jQuery/AJAX), via [HttpPost], which according to HTTP standards should not be cached as a request. Secondly, i don't want to cache purely based on the HTTP request arguments - the cache logic is a lot more complicated than that - there is actually two-level caching going on. As i hint to above, i need to use regular data-caching, e.g Cache["somekey"] = someObj;. I don't want to implement a generic caching mechanism where all calls via the service go through the cache first - i only want caching on this particular action method. First thought's would tell me to create another service (which inherits LocationService), and provide the caching workflow there (check cache first, if not there call db, add to cache, return result). That has two problems: The services are basic Class Libraries - no references to anything extra. I would need to add a reference to System.Web here. I would have to access the HTTP Context outside of the web application, which is considered bad practice, not only for testability, but in general - right? I also thought about using the Models folder in the Web Application (which i currently use only for ViewModels), but having a cache service in a models folder just doesn't sound right. So - any ideas? Is there a MVC-specific thing (like Action Filter's, for example) i can use here? General advice/tips would be greatly appreciated.

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• Dependency Injection in ASP.NET MVC NerdDinner App using Ninject

  - by shiju

  In this post, I am applying Dependency Injection to the NerdDinner application using Ninject. The controllers of NerdDinner application have Dependency Injection enabled constructors. So we can apply Dependency Injection through constructor without change any existing code. A Dependency Injection framework injects the dependencies into a class when the dependencies are needed. Dependency Injection enables looser coupling between classes and their dependencies and provides better testability of an application and it removes the need for clients to know about their dependencies and how to create them. If you are not familiar with Dependency Injection and Inversion of Control (IoC), read Martin Fowler’s article Inversion of Control Containers and the Dependency Injection pattern. The Open Source Project NerDinner is a great resource for learning ASP.NET MVC.  A free eBook provides an end-to-end walkthrough of building NerdDinner.com application. The free eBook and the Open Source Nerddinner application are extremely useful if anyone is trying to lean ASP.NET MVC. The first release of  Nerddinner was as a sample for the first chapter of Professional ASP.NET MVC 1.0. Currently the application is updating to ASP.NET MVC 2 and you can get the latest source from the source code tab of Nerddinner at http://nerddinner.codeplex.com/SourceControl/list/changesets. I have taken the latest ASP.NET MVC 2 source code of the application and applied  Dependency Injection using Ninject and Ninject extension Ninject.Web.Mvc.Ninject &  Ninject.Web.MvcNinject is available at http://github.com/enkari/ninject and Ninject.Web.Mvc is available at http://github.com/enkari/ninject.web.mvcNinject is a lightweight and a great dependency injection framework for .NET.  Ninject is a great choice of dependency injection framework when building ASP.NET MVC applications. Ninject.Web.Mvc is an extension for ninject which providing integration with ASP.NET MVC.Controller constructors and dependencies of NerdDinner application Listing 1 – Constructor of DinnersController  public DinnersController(IDinnerRepository repository) {     dinnerRepository = repository; }  Listing 2 – Constrcutor of AccountControllerpublic AccountController(IFormsAuthentication formsAuth, IMembershipService service) {     FormsAuth = formsAuth ?? new FormsAuthenticationService();     MembershipService = service ?? new AccountMembershipService(); }  Listing 3 – Constructor of AccountMembership – Concrete class of IMembershipService public AccountMembershipService(MembershipProvider provider) {     _provider = provider ?? Membership.Provider; }    Dependencies of NerdDinnerDinnersController, RSVPController SearchController and ServicesController have a dependency with IDinnerRepositiry. The concrete implementation of IDinnerRepositiry is DinnerRepositiry. AccountController has dependencies with IFormsAuthentication and IMembershipService. The concrete implementation of IFormsAuthentication is FormsAuthenticationService and the concrete implementation of IMembershipService is AccountMembershipService. The AccountMembershipService has a dependency with ASP.NET Membership Provider. Dependency Injection in NerdDinner using NinjectThe below steps will configure Ninject to apply controller injection in NerdDinner application.Step 1 – Add reference for NinjectOpen the  NerdDinner application and add  reference to Ninject.dll and Ninject.Web.Mvc.dll. Both are available from http://github.com/enkari/ninject and http://github.com/enkari/ninject.web.mvcStep 2 – Extend HttpApplication with NinjectHttpApplication Ninject.Web.Mvc extension allows integration between the Ninject and ASP.NET MVC. For this, you have to extend your HttpApplication with NinjectHttpApplication. Open the Global.asax.cs and inherit your MVC application from  NinjectHttpApplication instead of HttpApplication.   public class MvcApplication : NinjectHttpApplication Then the Application_Start method should be replace with OnApplicationStarted method. Inside the OnApplicationStarted method, call the RegisterAllControllersIn() method.   protected override void OnApplicationStarted() {     AreaRegistration.RegisterAllAreas();     RegisterRoutes(RouteTable.Routes);     ViewEngines.Engines.Clear();     ViewEngines.Engines.Add(new MobileCapableWebFormViewEngine());     RegisterAllControllersIn(Assembly.GetExecutingAssembly()); }  The RegisterAllControllersIn method will enables to activating all controllers through Ninject in the assembly you have supplied .We are passing the current assembly as parameter for RegisterAllControllersIn() method. Now we can expose dependencies of controller constructors and properties to request injectionsStep 3 – Create Ninject ModulesWe can configure your dependency injection mapping information using Ninject Modules.Modules just need to implement the INinjectModule interface, but most should extend the NinjectModule class for simplicity. internal class ServiceModule : NinjectModule {     public override void Load()     {                    Bind<IFormsAuthentication>().To<FormsAuthenticationService>();         Bind<IMembershipService>().To<AccountMembershipService>();                  Bind<MembershipProvider>().ToConstant(Membership.Provider);         Bind<IDinnerRepository>().To<DinnerRepository>();     } } The above Binding inforamtion specified in the Load method tells the Ninject container that, to inject instance of DinnerRepositiry when there is a request for IDinnerRepositiry and  inject instance of FormsAuthenticationService when there is a request for IFormsAuthentication and inject instance of AccountMembershipService when there is a request for IMembershipService. The AccountMembershipService class has a dependency with ASP.NET Membership provider. So we configure that inject the instance of Membership Provider. When configuring the binding information, you can specify the object scope in you application.There are four built-in scopes available in Ninject:Transient  -  A new instance of the type will be created each time one is requested. (This is the default scope). Binding method is .InTransientScope()   Singleton - Only a single instance of the type will be created, and the same instance will be returned for each subsequent request. Binding method is .InSingletonScope()Thread -  One instance of the type will be created per thread. Binding method is .InThreadScope() Request -  One instance of the type will be created per web request, and will be destroyed when the request ends. Binding method is .InRequestScope() Step 4 – Configure the Ninject KernelOnce you create NinjectModule, you load them into a container called the kernel. To request an instance of a type from Ninject, you call the Get() extension method. We can configure the kernel, through the CreateKernel method in the Global.asax.cs. protected override IKernel CreateKernel() {     var modules = new INinjectModule[]     {         new ServiceModule()     };       return new StandardKernel(modules); } Here we are loading the Ninject Module (ServiceModule class created in the step 3)  onto the container called the kernel for performing dependency injection.Source CodeYou can download the source code from http://nerddinneraddons.codeplex.com. I just put the modified source code onto CodePlex repository. The repository will update with more add-ons for the NerdDinner application.

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• Behind ASP.NET MVC Mock Objects

  - by imran_ku07

     Introduction:           I think this sentence now become very familiar to ASP.NET MVC developers that "ASP.NET MVC is designed with testability in mind". But what ASP.NET MVC team did for making applications build with ASP.NET MVC become easily testable? Understanding this is also very important because it gives you some help when designing custom classes. So in this article i will discuss some abstract classes provided by ASP.NET MVC team for the various ASP.NET intrinsic objects, including HttpContext, HttpRequest, and HttpResponse for making these objects as testable. I will also discuss that why it is hard and difficult to test ASP.NET Web Forms.      Description:           Starting from Classic ASP to ASP.NET MVC, ASP.NET Intrinsic objects is extensively used in all form of web application. They provide information about Request, Response, Server, Application and so on. But ASP.NET MVC uses these intrinsic objects in some abstract manner. The reason for this abstraction is to make your application testable. So let see the abstraction.           As we know that ASP.NET MVC uses the same runtime engine as ASP.NET Web Form uses, therefore the first receiver of the request after IIS and aspnet_filter.dll is aspnet_isapi.dll. This will start the application domain. With the application domain up and running, ASP.NET does some initialization and after some initialization it will call Application_Start if it is defined. Then the normal HTTP pipeline event handlers will be executed including both HTTP Modules and global.asax event handlers. One of the HTTP Module is registered by ASP.NET MVC is UrlRoutingModule. The purpose of this module is to match a route defined in global.asax. Every matched route must have IRouteHandler. In default case this is MvcRouteHandler which is responsible for determining the HTTP Handler which returns MvcHandler (which is derived from IHttpHandler). In simple words, Route has MvcRouteHandler which returns MvcHandler which is the IHttpHandler of current request. In between HTTP pipeline events the handler of ASP.NET MVC, MvcHandler.ProcessRequest will be executed and shown as given below,          void IHttpHandler.ProcessRequest(HttpContext context)          {                    this.ProcessRequest(context);          }          protected virtual void ProcessRequest(HttpContext context)          {                    // HttpContextWrapper inherits from HttpContextBase                    HttpContextBase ctxBase = new HttpContextWrapper(context);                    this.ProcessRequest(ctxBase);          }          protected internal virtual void ProcessRequest(HttpContextBase ctxBase)          {                    . . .          }             HttpContextBase is the base class. HttpContextWrapper inherits from HttpContextBase, which is the parent class that include information about a single HTTP request. This is what ASP.NET MVC team did, just wrap old instrinsic HttpContext into HttpContextWrapper object and provide opportunity for other framework to provide their own implementation of HttpContextBase. For example           public class MockHttpContext : HttpContextBase          {                    . . .          }                     As you can see, it is very easy to create your own HttpContext. That's what did the third party mock frameworks like TypeMock, Moq, RhinoMocks, or NMock2 to provide their own implementation of ASP.NET instrinsic objects classes.           The key point to note here is the types of ASP.NET instrinsic objects. In ASP.NET Web Form and ASP.NET MVC. For example in ASP.NET Web Form the type of Request object is HttpRequest (which is sealed) and in ASP.NET MVC the type of Request object is HttpRequestBase. This is one of the reason that makes test in ASP.NET WebForm is difficult. because their is no base class and the HttpRequest class is sealed, therefore it cannot act as a base class to others. On the other side ASP.NET MVC always uses a base class to give a chance to third parties and unit test frameworks to create thier own implementation ASP.NET instrinsic object.           Therefore we can say that in ASP.NET MVC, instrinsic objects are of type base classes (for example HttpContextBase) .Actually these base classes had it's own implementation of same interface as the intrinsic objects it abstracts. It includes only virtual members which simply throws an exception. ASP.NET MVC also provides the corresponding wrapper classes (for example, HttpRequestWrapper) which provides a concrete implementation of the base classes in the form of ASP.NET intrinsic object. Other wrapper classes may be defined by third parties in the form of a mock object for testing purpose.           So we can say that a Request object in ASP.NET MVC may be HttpRequestWrapper or may be MockRequestWrapper(assuming that MockRequestWrapper class is used for testing purpose). Here is list of ASP.NET instrinsic and their implementation in ASP.NET MVC in the form of base and wrapper classes. Base Class Wrapper Class ASP.NET Intrinsic Object Description HttpApplicationStateBase HttpApplicationStateWrapper Application HttpApplicationStateBase abstracts the intrinsic Application object HttpBrowserCapabilitiesBase HttpBrowserCapabilitiesWrapper HttpBrowserCapabilities HttpBrowserCapabilitiesBase abstracts the HttpBrowserCapabilities class HttpCachePolicyBase HttpCachePolicyWrapper HttpCachePolicy HttpCachePolicyBase abstracts the HttpCachePolicy class HttpContextBase HttpContextWrapper HttpContext HttpContextBase abstracts the intrinsic HttpContext object HttpFileCollectionBase HttpFileCollectionWrapper HttpFileCollection HttpFileCollectionBase abstracts the HttpFileCollection class HttpPostedFileBase HttpPostedFileWrapper HttpPostedFile HttpPostedFileBase abstracts the HttpPostedFile class HttpRequestBase HttpRequestWrapper Request HttpRequestBase abstracts the intrinsic Request object HttpResponseBase HttpResponseWrapper Response HttpResponseBase abstracts the intrinsic Response object HttpServerUtilityBase HttpServerUtilityWrapper Server HttpServerUtilityBase abstracts the intrinsic Server object HttpSessionStateBase HttpSessionStateWrapper Session HttpSessionStateBase abstracts the intrinsic Session object HttpStaticObjectsCollectionBase HttpStaticObjectsCollectionWrapper HttpStaticObjectsCollection HttpStaticObjectsCollectionBase abstracts the HttpStaticObjectsCollection class      Summary:           ASP.NET MVC provides a set of abstract classes for ASP.NET instrinsic objects in the form of base classes, allowing someone to create their own implementation. In addition, ASP.NET MVC also provide set of concrete classes in the form of wrapper classes. This design really makes application easier to test and even application may replace concrete implementation with thier own implementation, which makes ASP.NET MVC very flexable.

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• CodePlex Daily Summary for Sunday, April 04, 2010

  CodePlex Daily Summary for Sunday, April 04, 2010New ProjectsAcervo 2 - Gerenciador de coleções: Acervo 2 is a web application developed in ASP.NET 3.5 with Entity Framework, Coolite UI web controls and MySQL database that helps to catalog and ...AssemblyInfo Editor: AssemblyInfo Editor is a small Visual Studio 2010 extension I developed for my personal use mainly for automatically incrementing AssemblyVersion a...CommLine: It's a Command Line Interpreter. At the moment, it's a beta version, so I wait for developers that wanna help meFlowgraph Viewer: The flowgraph viewer enables users to view, build and share flowgraphs for the Crysis-franchise. It's built on Silverlight4, using MEF and Mvvmlight.Hash Calculator: WPF Windows 7 program to compute SHA1 & MD5 hash functions.MediaRSS library for .NET: This is a small set of libraries that allow you to create, read, and write MediaRSS files. By leveraging the syndication model object in .NET this...MEF Visualizer Tool: Helps to see what is going on inside the CompositionContainerone framework for developing asp.net project more elegent、flexible、and testable: if you are familiar with jsf、cdi、scoped javabean and work under asp.net, you may want to support aop and max flexibility and testability , all of ...Picasa Manager: A Silverlight Out Of Browser Application that Helps you manage your PicasaWeb albums in the easyest way possible.SharePhone: Windows Phone 7 library for connecting to SharePoint 2007/2010. Lets you work with SPWeb, SPList, reading/writing strong typed list items, user ...Silverlight Resource Extension: Silverlight Resource Extension. Extension silverlight project for use ResX resources and localize satellite dll.Silverlight Streamgraph: Streamgraph component for SilverlightTFTP Server: Managed TFTP server implementation, written in C#. Supports: - IPv4 and IPv6 - correct retry behavior. - TFTP options: block size, transfer size, a...Virtual UserGroup Video Helpers: This is a project that holds all the tools used by the C4MVC Virtual Usergroup. Tools written in C# and Powershell to automate, Live Meeting, Expr...xBlog: xBlog is a project to build a simple and extensible Blog Engine based on xml and linqXmlCodeEditor: XmlCodeEditor is a Silverlight 4 control based on RichTextControl that creates coloring and intellisense similar to the one in Visual Studio for ed...Zinc Launcher: Zinc Launcher is a simple Windows Media Center plugin that launches Zinc and attempts to manage the windows as seamlessly as possible. In addition ...New ReleasesAcervo 2 - Gerenciador de coleções: Acervo 2 - v1.0: Arquivos para implantação do sistema Acervo2 Aplicação web Web service Smart ClientAssemblyInfo Editor: Beta 1: Initial release of Assembly Info Editor. At this point, it is feature-complete and is relatively stable. There are undoubtedly some bugs to work o...Box2D.XNA: Box2D.XNA r70 Source Code and Solution: This version is synced to changeset 44697. This represents our official port of the C Box2D up to r70 on the Google Code project. With this versi...Boxee Launcher: Boxee Launcher Release 1.0.1.2: Will now stop Media Center playback before launching BoxeeBoxee Launcher: Boxee Launcher Release 1.0.1.3: Added a background window that attempts to display over the desktop and taskbar, and below Boxee and Media Center so that the desktop and taskbar a...CommLine: Beta Version 0.1: First Beta Of the AppCommLine: Source v0.1 Beta: Source Code C of 0.1 beta versionEncrypted Notes: Encrypted Notes 1.6.2: This is the latest version of Encrypted Notes (1.6.2), with general changes and improved randomness for the key generator. It has an installer that...Hash Calculator: HashCalculator: HashCalculator 1.0Hash Calculator: HashCalculator Source code: HashCalculator 1.0Hulu Launcher: Hulu Launcher 1.0.1.3: Added a background window that attempts to display over the desktop and taskbar, and below Hulu and Media Center so that the desktop and taskbar ar...Hulu Launcher: Hulu Launcher Release 1.0.1.2: Hulu Launcher will now stop playback in Media Center before launching Hulu Desktop.Innovative Games: 4.3 - Sprite Effects: Source code download for chapter 4.3 - "Sprite Effects"MediaRSS library for .NET: 0.1: Alpha release. Majority of MediaRSS spec is supported. A small set of unit test / sample code are included. A lightly tested CustomFormatter object...MEF Visualizer Tool: MEF Visualizer Tool 0.1: Help to see what going on in side CompositionContainer Container = new CompositionContainer( new AggregateCatalog( ...Ncqrs Framework - A CQRS framework for .NET: Ncqrs with sample application: This is the first release of the Ncqrs Framework. It contains the Ncqrs source code and a runnable sample application. All the code in this release...Rubik Cube's 3D Silverlight 3.0 Animated Solution: Rubik Cube 3D with Animated Solution: This project is a realization of Silverlight 3.0 Rubik Cube 3D with Animated Solution. The Solution is available for 3x3x3 cube, other features are...Scrabler: scrabler release 0.6.2.5: fixed a bug that werent executed some scriptsSharePhone: SharePhone: Initial release with basic functionality: Open SharePoint webs and subwebs Retrieve lists on SPWeb objects Read metadata/properties on lists ...SharePhone: SharePhone v.1.0.1: Fixed a bug that prevented saving list items to SharePointSharePoint Labs: SPLab4001A-FRA-Level100: SPLab4001A-FRA-Level100 This SharePoint Lab will teach you the first best practice you should apply when writing code with the SharePoint API. Lab ...Silverlight Resource Extension: ResourceExtension (alpha): Alpha version is not stable. Only for review.Silverlight Streamgraph: Port from processing.org: A port from the processing.org streamgraph. Code-heavy with very little XAML involved at this point.Theocratic Ministry School System: TMSS - Ver 1.1.1: What’s New! Added Menu Options 2010 Schedule Access 2007 Runtime There are still many uncompleted items so this is still a conceptual release....Theocratic Ministry School System: TMSS - Ver 1.1.2: Fixed the Schedule Import. Need needs to be tested. Click import button and make sure you can get the 2010 Schedule from the internet.thinktecture Starter STS (Community Edition): StarterSTS v1.0 RTW: Version 1.0 RTWTribe.Cache: Tribe.Cache Alpha - 0.2.0.0: Tribe.Cache Alpha - 0.2.0.0 - Now has sliding and absolute expiration on cache entries. Functional Alpha Release - But do not use in productionTwitterVB - A .NET Twitter Library: TwitterVB-2.3.1: This is mostly a minor release that adds br.st URL shortening to the menu (API key from http://br.st required)Virtu: Virtu 0.8.1: Source Requirements.NET Framework 3.5 with Service Pack 1 Visual Studio 2008 with Service Pack 1, or Visual C# 2008 Express Edition with Service Pa...Visual Studio DSite: Advanced C++ Calculator: An advanced visual c 2008 calculator that can do all your basic operations, plus some advanced mathematical functions. Source Code Only.xnaWebcam: xnaWebcam 0.3: xnaWebcam 0.3 Version 0.3: -ResolutionSet: 400x300 (Default), 800x600, 1024x720 -Settings Window got Icon -Settings Window Changes -DevConsole.cs ...Most Popular ProjectsRawrWBFS ManagerMicrosoft SQL Server Product Samples: DatabaseASP.NET Ajax LibrarySilverlight ToolkitAJAX Control ToolkitWindows Presentation Foundation (WPF)ASP.NETMicrosoft SQL Server Community & SamplesDotNetNuke® Community EditionMost Active ProjectsGraffiti CMSnopCommerce. Open Source online shop e-commerce solution.RawrFacebook Developer ToolkitjQuery Library for SharePoint Web ServicesLINQ to TwitterBlogEngine.NETN2 CMSBase Class LibrariesFarseer Physics Engine

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• What's new in EJB 3.2 ? - Java EE 7 chugging along!

  - by arungupta

  EJB 3.1 added a whole ton of features for simplicity and ease-of-use such as @Singleton, @Asynchronous, @Schedule, Portable JNDI name, EJBContainer.createEJBContainer, EJB 3.1 Lite, and many others. As part of Java EE 7, EJB 3.2 (JSR 345) is making progress and this blog will provide highlights from the work done so far. This release has been particularly kept small but include several minor improvements and tweaks for usability. More features in EJB.Lite Asynchronous session bean Non-persistent EJB Timer service This also means these features can be used in embeddable EJB container and there by improving testability of your application. Pruning - The following features were made Proposed Optional in Java EE 6 and are now made optional. EJB 2.1 and earlier Entity Bean Component Contract for CMP and BMP Client View of an EJB 2.1 and earlier Entity Bean EJB QL: Query Language for CMP Query Methods JAX-RPC-based Web Service Endpoints and Client View The optional features are moved to a separate document and as a result EJB specification is now split into Core and Optional documents. This allows the specification to be more readable and better organized. Updates and Improvements Transactional lifecycle callbacks in Stateful Session Beans, only for CMT. In EJB 3.1, the transaction context for lifecyle callback methods (@PostConstruct, @PreDestroy, @PostActivate, @PrePassivate) are defined as shown. @PostConstruct @PreDestroy @PrePassivate @PostActivate Stateless Unspecified Unspecified N/A N/A Stateful Unspecified Unspecified Unspecified Unspecified Singleton Bean's transaction management type Bean's transaction management type N/A N/A In EJB 3.2, stateful session bean lifecycle callback methods can opt-in to be transactional. These methods are then executed in a transaction context as shown. @PostConstruct @PreDestroy @PrePassivate @PostActivate Stateless Unspecified Unspecified N/A N/A Stateful Bean's transaction management type Bean's transaction management type Bean's transaction management type Bean's transaction management type Singleton Bean's transaction management type Bean's transaction management type N/A N/A For example, the following stateful session bean require a new transaction to be started for @PostConstruct and @PreDestroy lifecycle callback methods. @Statefulpublic class HelloBean {   @PersistenceContext(type=PersistenceContextType.EXTENDED)   private EntityManager em;    @TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)   @PostConstruct   public void init() {        myEntity = em.find(...);   }   @TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)    @PostConstruct    public void destroy() {        em.flush();    }} Notice, by default the lifecycle callback methods are not transactional for backwards compatibility. They need to be explicitly opt-in to be made transactional. Opt-out of passivation for stateful session bean - If your stateful session bean needs to stick around or it has non-serializable field then the bean can be opt-out of passivation as shown. @Stateful(passivationCapable=false)public class HelloBean {    private NonSerializableType ref = ... . . .} Simplified the rules to define all local/remote views of the bean. For example, if the bean is defined as: @Statelesspublic class Bean implements Foo, Bar {    . . .} where Foo and Bar have no annotations of their own, then Foo and Bar are exposed as local views of the bean. The bean may be explicitly marked @Local as @Local@Statelesspublic class Bean implements Foo, Bar {    . . .} then this is the same behavior as explained above, i.e. Foo and Bar are local views. If the bean is marked @Remote as: @Remote@Statelesspublic class Bean implements Foo, Bar {    . . .} then Foo and Bar are remote views. If an interface is marked @Local or @Remote then each interface need to be explicitly marked explicitly to be exposed as a view. For example: @Remotepublic interface Foo { . . . }@Statelesspublic class Bean implements Foo, Bar {    . . .} only exposes one remote interface Foo. Section 4.9.7 from the specification provide more details about this feature. TimerService.getAllTimers is a newly added convenience API that returns all timers in the same bean. This is only for displaying the list of timers as the timer can only be canceled by its owner. Removed restriction to obtain the current class loader, and allow to use java.io package. This is handy if you want to do file access within your beans. JMS 2.0 alignment - A standard list of activation-config properties is now defined destinationLookup connectionFactoryLookup clientId subscriptionName shareSubscriptions Tons of other clarifications through out the spec. Appendix A provide a comprehensive list of changes since EJB 3.1. ThreadContext in Singleton is guaranteed to be thread-safe. Embeddable container implement Autocloseable. A complete replay of Enterprise JavaBeans Today and Tomorrow from JavaOne 2012 can be seen here (click on CON4654_mp4_4654_001 in Media). The specification is still evolving so the actual property or method names or their actual behavior may be different from the currently proposed ones. Are there any improvements that you'd like to see in EJB 3.2 ? The EJB 3.2 Expert Group would love to hear your feedback. An Early Draft of the specification is available. The latest version of the specification can always be downloaded from here. Java EE 7 Specification Status EJB Specification Project JIRA of EJB Specification JSR Expert Group Discussion Archive These features will start showing up in GlassFish 4 Promoted Builds soon.

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• CodePlex Daily Summary for Wednesday, March 31, 2010

  CodePlex Daily Summary for Wednesday, March 31, 2010New ProjectsBase Class Libraries: The Base Class Libraries site hosts samples, previews, and prototypes from the BCL team. BB Scheduler - BroadBand Scheduler: Broadband Scheduler is highly useful as it helps the user to set the time when the computer will automatically enable the Broadband (Internet) conn...BFBC2 PRoCon: BFBC2 PRoCon makes it easier for Bad Company 2 GSP's and private server owners to administer their BFBC2 servers. It's developed in C# and targete...Business Process Management Virtual Environment (BPMVE): This BPMVE project has been separated into 3 different projects. BPMVE_DataStructure project contains all data structures (classes and attribute...Business Rule Engine BizUnit Test Steps: Business Rule Engine BizUnit Test StepsCint: CintContent Edit Extender for Ajax.Net: The Content Edit Extender is an Ajax.Net control extender that allows in-place editing of a div tag (panel). Double-click to edit, hit enter or tab...COV Game: Cov game is a worms like game made on Silverlight with Python server.Cybera: A continuing development project of the existing but now generally inactive former Cybera project.DotNetCRM Community Edition: DotNetCRM Community Edition is an open source, enterprise class CRM built on the .NET platform. It is designed to be extensible, configurable, data...EAV: A sample EAV pattern for SQL Server with: Tables and indexes Partial referential integrity Partial data typing Updatable views (like normal SQL table)EditRegion.MVC: EditRegion.MVC may be all you want, when you do not want a full CMS. It allows html areas to be edited by nominated users or roles. The API follo...Firestarter Modeller: Firestarter ModellerHabanero.Testability: Habanero.TestabilityProSoft CMS: CMS System - scalable over an undeclared amount of servers - publishing services - version control of sitesPS-Blog.net: This is my first project here on codeplex. I would like to write my own blog software. Any comments or critcs are welcome.ReleaseMe: ReleaseMe is a simple little tool I use to copy websites, and custom Window Services, from my development machine to a specified production machin...SAAS-RD: SAAS-RD: uma ferrameta utilizada para prover integração de SaaS com aplicações externasSample Web Application using Telerik's OpenAccess ORM: Sample Web Site Application Project that uses Telerik's OpenAccess ORM for data access.Sistema Facturacion: En el proyecto de Sistema de Facturacion se desarrollara una aplicacion para el total control de un establecimiento comercial Smooth Habanero: Smooth HabaneroSouthEast Conference 2011: For the Florida Institute of Technology IEEE Chapter regarding the Southeast Hardware Conference held in Nashville, TN 2011.SQL Server Bible Standards: A SQL Server Design and Development standards document. SSAS Profiler Trace Scheduler: AS Profiler Scheduler is a tool that will enable Scheduling of SQL AS Tracing using predefined Profiler Templates. For tracking different issues th...Symbolic Algebra: Another attempt to make an algebric system but to be natively in C# under the .net framework. Theocratic Ministry School System: This is an Open Source Theocratic Ministry School System designed for Jehovah's Witnesses. It will include much of the same features as the TMS ver...Weather Report WebControls: The First Release Version:1.0.10330.2334WPF 3D Labyrinth: A project for "Design and Analysis of Computer Algorithms" subject at Kaunas University of Technology. Building a 3D labyrinth with a figure which ...WPF Zen Garden: This is intended to be a gallery for WPF Style sheets in the form of Css Zen Garden. New ReleasesAPSales CRM - Software as a Service: APSales 0.1.3: This version add some interesting features to the project: Implement "Filter By Additional Fields" in view edit Implement quick create function Im...Base Class Libraries: BigRational: BigRational builds on the BigInteger introduced in .NET Framework 4 to create an arbitrary-precision rational number type. A rational number is a ...Base Class Libraries: Long Path: The long path wrapper provides functionality to make it easier to work with paths that are longer than the current 259 character limit of the Syste...Base Class Libraries: PerfMonitor: PerfMonitor is a command-line tool for profiling the system using Event Tracing for Windows (ETW). PerfMonitor is built on top of the TraceEvent li...Base Class Libraries: TraceEvent: TraceEvent is an experimental library that greatly simplifies reading Event Tracing for Windows (ETW) events. It is used by the PerfMonitor tool. ...BB Scheduler - BroadBand Scheduler: Broadband Scheduler v2.0: - Broadband service has some of the cheap and best monthly plans for the users all over the nation. And some of the plans include unlimited night d...BuildTools - Toolset for automated builds: BuildTools 2.0 Mar 2010 Milestone: The Mar 2010 Milestone release is a contains a bug fixes for projects not explicitly setting the StartingDate property, and no longer breaks when t...Business Rule Engine BizUnit Test Steps: BRE BizUnit Test Steps Ver. 1.0: Version 1.0Claymore MVP: Claymore 1.1.0.0: Changelog Added Compact Framework support Added fluent interface to configure the library.Content Edit Extender for Ajax.Net: ContentEditExtender 1.0 for Ajax.Net: Complete with source control and test/example Website and Web Service. Built with Visual Studio 2008 with the 3.5 BCL. Control requires the AjaxCon...dylan.NET: dylan.NET v. 9.6: This stable version of the compiler for both .NET 3.5 and 4.0 adds the loading of numbers in a bult-in fashion. See code below: #refasm mscorlib...EAV: March 2010: The initial release as demoed at the SSWUG Virtual Conference Spring 2010Fax .NET: Fax .NET 1.0.1: FIX : bugs for x64 and WOW64 architecture. The zip file include : Binary file Demo executable file Help fileFluent Ribbon Control Suite: Fluent Ribbon Control Suite 1.0 for NET 4.0 RC: Includes: Fluent.dll (with .pdb and .xml) compiled with .NET 4.0 RC Test application compiled with .NET 4.0 RC SourcesIceChat: IceChat 2009 Alpha 12.1 Full Install: Build Alpha 12.1 - March 30 2010 Fix Nick Name Change for Tabs/Server List for Queries Fix for running Channel List Multiple Times, clears list n...Import Excel data to SharePoint List: Import Data from Spreadsheet to SP List V1.5 x64: Import from Spreadsheet to a SharePoint List is the missing facet to the WSS 3.0 / MOSS 2007 List features. SharePoint lets a user create a custom...LINQ to Twitter: LINQ to Twitter Beta v2.0.9: New items added since v1.1 include: Support for OAuth (via DotNetOpenAuth), secure communication via https, VB language support, serialization of ...mojoPortal: 2.3.4.1: see release notes on mojoportal.com http://www.mojoportal.com/mojoportal-2341-released.aspxocculo: test: Release build for testers.PowerShell ToodleDo Module: 0.1: Initial Development Release - Very rough build.Quick Performance Monitor: Version 1.2: Fixed issue where app crash when performance counter disappear or becomes unavailable while the application is running. For now the exception is si...Quick Performance Monitor: Version 1.3: Add 'view last error'Rule 18 - Love your clipboard: Rule 18 (Visual Studio 2010 + .NET 4 RC Version): This is the second public beta for the first version of Rule 18. It has had a extensive private beta and been used in big presentations since the ...Selection Maker: Selection Maker 1.5: New Features:If the source folder does not exist,a dialog box will appear and ask the user if he/she wants to create that folder or if select anoth...sPATCH: sPatch v0.9a: + Fixed: wrong path to elementclient.exeSQL Server Bible Standards: March 2010: Initial release as presented at SSWUG Virtual Conference Spring 2010Survey - web survey & form engine: Source Code Documentation: Documentation.chm file as published with Nsurvey v. 1.9.1 - april 2005 Basic technical documentation and description of source code for developers...Theocratic Ministry School System: Theocratic Ministry School System - TMSS: This is the first release of TMSS. It is far from complete but demonstrates the possiablities of what can be done with Access 2007 using developer ...Weather Report WebControls: WeatherReport Controls: 本下载包含一个已经经过编译的二进制运行库和一个测试的WebApplication项目，是2010年3月30日发布的Most Popular ProjectsRawrWBFS ManagerASP.NET Ajax LibraryMicrosoft SQL Server Product Samples: DatabaseSilverlight ToolkitAJAX Control ToolkitWindows Presentation Foundation (WPF)LiveUpload to FacebookASP.NETMicrosoft SQL Server Community & SamplesMost Active ProjectsRawrjQuery Library for SharePoint Web ServicesBase Class LibrariesBlogEngine.NETManaged Extensibility FrameworkFarseer Physics EngineGraffiti CMSMicrosoft Biology FoundationLINQ to Twitterpatterns & practices – Enterprise Library

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• CodePlex Daily Summary for Thursday, December 23, 2010

  CodePlex Daily Summary for Thursday, December 23, 2010Popular ReleasesSSH.NET Library: 2010.12.23: This release includes some bug fixes and few new fetures. Fixes Allow to retrieve big directory structures ssh-dss algorithm is fixed Populate sftp file attributes New Features Support for passhrase when private key is used Support added for diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha256 and diffie-hellman-group-exchange-sha1 key exchange algorithms Allow to provide multiple key files for authentication Add support for "keyboard-interactive" authentication method...ASP.NET MVC SiteMap provider: MvcSiteMapProvider 2.3.0: Using NuGet?MvcSiteMapProvider is also listed in the NuGet feed. Learn more... Like the project? Consider a donation!Donate via PayPal via PayPal. Release notesThis will be the last release targeting ASP.NET MVC 2 and .NET 3.5. MvcSiteMapProvider 3.0.0 will be targeting ASP.NET MVC 3 and .NET 4 Web.config setting skipAssemblyScanOn has been deprecated in favor of excludeAssembliesForScan and includeAssembliesForScan ISiteMapNodeUrlResolver is now completely responsible for generating th...SuperSocket, an extensible socket application framework: SuperSocket 1.3 beta 2: Compared with SuperSocket 1.3 beta 1, the changes listed below have been done in SuperSocket 1.3 beta 2: added supports for .NET 3.5 replaced Logging Application Block of EntLib with Log4Net improved the code about logging fixed a bug in QuickStart sample project added IPv6 supportTibiaPinger: TibiaPinger v1.0: TibiaPinger v1.0Media Companion: Media Companion 3.400: Extract the entire archive to a folder which has user access rights, eg desktop, documents etc. A manual is included to get you startedPackage that minifies and combines JavaScript and CSS files: Release 1.1: Bug fixes. The package now correctly handles inlined images and image urls in CSS files surrounded by quotes. CombineAndMinify can now be used in conjunction with Microsoft's Sprite and Image Optimization Framework. That framework combines several small images into one, reducing overall load times.Multicore Task Framework: MTF 1.0.1: Release 1.0.1 of Multicore Task Framework.SQL Monitor - tracking sql server activities: SQL Monitor 3.0 alpha 7: 1. added script save/load in user query window 2. fixed problem with connection dialog when choosing windows auth but still ask for user name 3. auto open user table when double click one table node 4. improved alert message, added log only methodOpen NFe: Open NFe 2.0 (Beta): Última versão antes da versão final a ser lançada nos próximos dias.EnhSim: EnhSim 2.2.6 ALPHA: 2.2.6 ALPHAThis release supports WoW patch 4.03a at level 85 To use this release, you must have the Microsoft Visual C++ 2010 Redistributable Package installed. This can be downloaded from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=A7B7A05E-6DE6-4D3A-A423-37BF0912DB84 To use the GUI you must have the .NET 4.0 Framework installed. This can be downloaded from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=9cfb2d51-5ff4-4491-b0e5-b386f32c0992 - Fixing up some r...ASP.NET MVC Project Awesome (jQuery Ajax helpers): 1.4.3: Helpers (controls) that you can use to build highly responsive and interactive Ajax-enabled Web applications. These helpers include Autocomplete, AjaxDropdown, Lookup, Confirm Dialog, Popup Form, Popup and Pager new stuff: Improvements for confirm, popup, popup form RenderView controller extension the user experience for crud in live demo has been substantially improved + added search all the features are shown in the live demoGanttPlanner: GanttPlanner V1.0: GanttPlanner V1.0 include GanttPlanner.dll and also a Demo application.N2 CMS: 2.1 release candidate 3: * Web platform installer support available N2 is a lightweight CMS framework for ASP.NET. It helps you build great web sites that anyone can update. Major Changes Support for auto-implemented properties ({get;set;}, based on contribution by And Poulsen) A bunch of bugs were fixed File manager improvements (multiple file upload, resize images to fit) New image gallery Infinite scroll paging on news Content templates First time with N2? Try the demo site Download one of the templ...TweetSharp: TweetSharp v2.0.0.0 - Preview 6: Documentation for this release may be found at http://tweetsharp.codeplex.com/wikipage?title=UserGuide&referringTitle=Documentation. Note: This code is currently preview quality. Preview 6 ChangesMaintenance release with user reported fixes Preview 5 ChangesMaintenance release with user reported fixes Preview 4 ChangesReintroduced fluent interface support via satellite assembly Added entities support, entity segmentation, and ITweetable/ITweeter interfaces for client development Numer...Team Foundation Server Administration Tool: 2.1: TFS Administration Tool 2.1, is the first version of the TFS Administration Tool which is built on top of the Team Foundation Server 2010 object model. TFS Administration Tool 2.1 can be installed on machines that are running either Team Explorer 2010, or Team Foundation Server 2010.SubtitleTools: SubtitleTools 1.3: - Added .srt FileAssociation & Win7 ShowRecentCategory feature. - Applied UnifiedYeKe to fix Persian search problems. - Reduced file size of Persian subtitles for uploading @OSDB.Facebook C# SDK: 4.1.0: - Lots of bug fixes - Removed Dynamic Runtime Language dependencies from non-dynamic platforms. - Samples included in release for ASP.NET, MVC, Silverlight, Windows Phone 7, WPF, WinForms, and one Visual Basic Sample - Changed internal serialization to use Json.net - BREAKING CHANGE: Canvas Session is no longer support. Use Signed Request instead. Canvas Session has been deprecated by Facebook. - BREAKING CHANGE: Some renames and changes with Authorizer, CanvasAuthorizer, and Authorization ac...NuGet: NuGet 1.0 build 11217.102: Note: this release is slightly newer than RC1, and fixes a couple issues relating to updating packages to newer versions. NuGet is a free, open source developer focused package management system for the .NET platform intent on simplifying the process of incorporating third party libraries into a .NET application during development. This release is a Visual Studio 2010 extension and contains the the Package Manager Console and the Add Package Dialog. This new build targets the newer feed (h...WCF Community Site: WCF Web APIs 10.12.17: Welcome to the second release of WCF Web APIs on codeplex Here is what is new in this release. WCF Support for jQuery - create WCF web services that are easy to consume from JavaScript clients, in particular jQuery. Better support for using JsonValue as dynamic Support for JsonValue change notification events for databinding and other purposes Support for going between JsonValue and CLR types WCF HTTP - create HTTP / REST based web services. This is a minor release which contains fixe...Orchard Project: Orchard 0.9: Orchard Release Notes Build: 0.9.253 Published: 12/16/2010 How to Install OrchardTo install the Orchard tech preview using Web PI, follow these instructions: http://www.orchardproject.net/docs/Installing-Orchard-Using-Web-PI.ashx Web PI will detect your hardware environment and install the application. --OR-- Alternatively, to install the release manually, download the Orchard.Web.0.9.253.zip file. The zip contents are pre-built and ready-to-run. Simply extract the contents of the Orch...New ProjectsArabic Silverlight IE8 Web Slices: Group of IE8 web slices built on SilverlightAssaultCube Special Edition: Making the classic better!Blazonisation: If have emblem of some state, but don't know anything about it, you can use this tool to resolve your problem. Content Maintenance Dashboard: Content Maintenance Dashboard is a package for Umbraco which lets you bulk publlish, unpublish, move and delete of content items.DFTBASP: Drop files on the window choose permissions or Just backup option DMNarrator Manager: A tool for RPG Narrators (and dungeon masters). First version is focused to old Wolrd of DarknessdnnGr2 - Free DotNetNuke Skin: A free DotNetNuke skin initially created for the DotNetNuke Skinning Presentation at the 2nd meeting of the DNN Greek Community.Duplicate File Explorer: File search utility, that also shows what files are duplicate by name. Supports searching up to 3 different folders at one time, excluding folders or extensions and multiple search patterns.Elmax: Yet another easy to use C++ XML parsing library on Windows! Tutorial coming soon!Firemap: Generates a html page which displays key performance statistics of chosen computers. Jumony Guide: Guide for Jumony Milestone 1Loc Tracker: Location tracking system for android and a php server for managing setup of triggers and events to be notified.MBDeveloper: This is my personal project.MECMS: Its an self-developed ecms.Media Companion: Media Companion is a windows program that allows people to catalogue and browse movie and tv episode collections. Folders are scanned and information is automatically gathered from various sources, including posters, fanart and episode screenshots. MOSS 2007 WebPart for SSO to BlackBoard: This project includes a MOSS 2007 WebPart for Single Sign On (SSO) to a Blackboard 9 Learning Management System. Existing projects and code samples do not include resources for SharePoint 2007 (MOSS) or C#. The goal of to provide these missing resources.MutitouchTest Flash AS3 on IOS (iPhone iPad): MutitouchTest Flash AS3 on IOS (iPhone iPad) www.fbair.net ??????Ipad ????? ??, ???????????????????, ???11?. iTouch4 ????5?? ??????? ? ? ??? ???????????. iPad??????????????Netropya XCogen: XCogen is an xml file config generator for Castle, Unity Spring and StructureMap containers. It's a simple console application for post-build action.Nota Algoritmica EUI: Programa que obtiene del moodle de la asignatura las notas y calcula la media final.Powershell CmdLets for Citrix NetScaler: Powershell CmdLets for the Citrix Netscaler product. This enables for querying & modifying the netscaler configuration through powershell.Scenario Framework - BPM Suite: Business Process Management SystemSchool Authorization System: School Authorization SystemSharePoint Delete Dead Users: This is a small WPF Application that presents all dead users it finds and allows the user to delete them from SharePoint. dead users are users that are not found inside active directory. There is also an LDAP Filter to speed up the query from active directorySugataTools: SugataTools are the helper classes that I usually use in my projects.The Phoenix Foundation - OSAL: Another OSAL for Windows (desktop/mobile) & Linux support.TibiaPinger: Tibia Pinger, Tools, Bot, ArkBot, Tibia, NeoBot, TibiaAuto, NG, ElfBottracer: Modernizes the System.Diagnostics trace infrastructure APIs to bring dynamism, testability and composability to .NET logging.uQR: uQR is an Umbraco package which adds the ability to generate dynamic QR Codes to an Umbraco website.User Account Picture Manager: This little app will try to fetch a users picture from active directory (thumbnailPhoto) and sets this picture on Windows Vista/2008/7/2008 R2 as User Account PictureVirtual Shell Service: Virtual Shell Service, is a service that runs on your server allowing trusted users to interact with the system via a sand boxed environment. The service has been designed to support mapping terminal commands in different ways via plugins and XML mappingWindows Live Writer Codehighlighting Plugin For Alex Gorbatchev's SyntaxHighligh: Windows Live Writer Codehighlighting Plugin For Alex Gorbatchev's SyntaxHighlighter. More information about the proect please visit http://tugberkugurlu.com/41

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• What&rsquo;s new in MVVM Light V3

  - by Laurent Bugnion

  V3 of the MVVM Light Toolkit was released during MIX10, after quite a long alpha stage. This post lists the new features in MVVM Light V3. Compatibility MVVM Light Toolkit V3 can be installed for the following tools and framework versions: Visual Studio 2008 SP1, Expression Blend 3 Windows Presentation Foundation 3.5 SP1 Silverlight 3 Visual Studio 2010 RC, Expression Blend 4 beta Windows Presentation Foundation 3.5 SP1 Windows Presentation Foundation 4 RC Silverlight 3 Silverlight 4 RC For more information about installing the MVVM Light Toolkit V3, please visit this page. For cleaning up existing installation, see this page. New in V3 RTM The following features have been added after V3 alpha3: Project template for the Windows Phone 7 series (Silverlight) This new template allows you to create a new MVVM Light application in Visual Studio 2010 RC and to run it in the Windows Phone 7 series emulator. This template uses the Silverlight 3 version of the MVVM Light Toolkit V3. At this time, only the essentials features of the GalaSoft.MvvmLight.dll assembly are supported on the phone. New in V3 alpha3 The following features have been added after V3 alpha2: New logo An awesome logo has been designed for MVVM Light by Philippe Schutz. DispatcherHelper class (in GalaSoft.MvvmLight.Extras.dll) This class is useful when you work on multi-threaded WPF or Silverlight applications. Initializing: The DispatcherHelper class must be initialized in the UI thread. For example, you can initialize the class in a Silverlight application’s Application_Startup event handler, or in the WPF application’s static App constructor (in App.xaml). // Initializing in Silverlight (in App.xaml) private void Application_Startup( object sender, StartupEventArgs e) { RootVisual = new MainPage(); DispatcherHelper.Initialize(); } // Initializing in WPF (in App.xaml) static App() { DispatcherHelper.Initialize(); } Verifying if a property exists The ViewModelBase.RaisePropertyChanged method now checks if a given property name exists on the ViewModel class, and throws an exception if that property cannot be found. This is useful to detect typos in a property name, for example during a refactoring. Note that the check is only done in DEBUG mode. Replacing IDisposable with ICleanup The IDisposable implementation in the ViewModelBase class has been marked obsolete. Instead, the ICleanup interface (and its Cleanup method) has been added. Implementing IDisposable in a ViewModel is still possible, but must be done explicitly. IDisposable in ViewModelBase was a bad practice, because it supposes that the ViewModel is garbage collected after Dispose is called. instead, the Cleanup method does not have such expectation. The ViewModelLocator class (created when an MVVM Light project template is used in Visual Studio or Expression Blend) exposes a static Cleanup method, which should in turn call each ViewModel’s Cleanup method. The ViewModel is free to override the Cleanup method if local cleanup must be performed. Passing EventArgs to command with EventToCommand The EventToCommand class is used to bind any event to an ICommand (typically on the ViewModel). In this case, it can be useful to pass the event’s EventArgs parameter to the command in the ViewModel. For example, for the MouseEnter event, you can pass the MouseEventArgs to a RelayCommand<MouseEventArgs> as shown in the next listings. Note: Bringing UI specific classes (such as EventArgs) into the ViewModel reduces the testability of the ViewModel, and thus should be used with care. Setting EventToCommand and PassEventArgsToCommand: <Grid x:Name="LayoutRoot"> <i:Interaction.Triggers> <i:EventTrigger EventName="MouseEnter"> <cmd:EventToCommand Command="{Binding MyCommand}" PassEventArgsToCommand="True" /> </i:EventTrigger> </i:Interaction.Triggers> </Grid> Getting the EventArgs in the command public RelayCommand<MouseEventArgs> MyCommand { get; private set; } public MainViewModel() { MyCommand = new RelayCommand<MouseEventArgs>(e => { // e is of type MouseEventArgs }); } Changes to templates Various changes have been made to project templates and item templates to make them more compatible with Silverlight 4 and to improve their visibility in Visual Studio and Expression Blend. Bug corrections When a message is sent through the Messenger class using the method Messenger.Default.Send<T>(T message, object token), and the token is a simple value (for example int), the message was not sent correctly. This bug is now corrected. New in V3 The following features have been added after V2. Sending messages with callback Certain classes have been added to the GalaSoft.MvvmLight.Messaging namespace, allowing sending a message and getting a callback from the recipient. These classes are: NotificationMessageWithCallback: Base class for messages with callback. NotificationMessageAction: A class with string notification, and a parameterless callback. NotificationMessageAction<T>: A class with string notification, and a callback with a parameter of type T. To send a message with callback, use the following code: var message = new NotificationMessageAction<bool>( "Hello world", callbackMessage => { // This is the callback code if (callbackMessage) { // ... } }); Messenger.Default.Send(message); To register and receive a message with callback, use the following code: Messenger.Default.Register<NotificationMessageAction<bool>>( this, message => { // Do something // Execute the callback message.Execute(true); }); Messenger.Default can be overriden The Messenger.Default property can also be replaced, for example for unit testing purposes, by using the Messenger.OverrideDefault method. All the public methods of the Messenger class have been made virtual, and can be overridden in the test messenger class. Sending messages to interfaces In V2, it was possible to deliver messages targeted to instances of a given class. in V3 it is still possible, but in addition you can deliver a message to instances that implement a certain interface. The message will not be delivered to other recipients. Use the overload Messenger.Default.Send<TMessage, TTarget>(TMessage message) where TTarget is, in fact, an interface (for example IDisposable). Of course the recipient must register to receive the type of message TMessage. Sending messages with a token Messages can now be sent through the Messenger with a token. To send a message with token, use the method overload Send<TMessage>(TMessage message, object token). To receive a message with token, use the methods Register<TMessage>(object recipient, object token, Action<TMessage> action) or Register<TMessage>(object recipient, object token, bool receiveDerivedMessagesToo, Action<TMessage> action) The token can be a simple value (int, string, etc…) or an instance of a class. The message is not delivered to recipients who registered with a different token, or with no token at all. Renaming CommandMessage to NotificationMessage To avoid confusion with ICommand and RelayCommand, the CommandMessage class has been renamed to NotificationMessage. This message class can be used to deliver a notification (of type string) to a recipient. ViewModelBase constructor with IMessenger The ViewModelBase class now accepts an IMessenger parameter. If this constructor is used instead of the default empty constructor, the IMessenger passed as parameter will be used to broadcast a PropertyChangedMessage when the method RaisePropertyChanged<T>(string propertyName, T oldValue, T newValue, bool broadcast) is used. In the default ViewModelBase constructor is used, the Messenger.Default instance will be used instead. EventToCommand behavior The EventToCommand behavior has been added in V3. It can be used to bind any event of any FrameworkElement to any ICommand (for example a RelayCommand located in the ViewModel). More information about the EventToCommand behavior can be found here and here. Updated the project templates to remove the sample application The project template has been updated to remove the sample application that was created every time that a new MVVM Light application was created in Visual Studio or Blend. This makes the creation of a new application easier, because you don’t need to remove code before you can start writing code. Bug corrections Some bugs that were in Version 2 have been corrected: In some occasions, an exception could be thrown when a recipient was registered for a message at the same time as a message was received. New names for DLLs If you upgrade an existing installation, you will need to change the reference to the DLLs in C:\Program Files\Laurent Bugnion (GalaSoft)\Mvvm Light Toolkit\Binaries. The assemblies have been moved, and the versions for Silverlight 4 and for WPF4 have been renamed, to avoid some confusion. It is now easier to make sure that you are using the correct DLL. WPF3.5SP1, Silverlight 3 When using the DLLs, make sure that you use the correct versions. WPF4, Silverlight 4 When using the DLLs, make sure that you use the correct versions.   Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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• Software development is (mostly) a trade, and what to do about it

  - by Jeff

  (This is another cross-post from my personal blog. I don’t even remember when I first started to write it, but I feel like my opinion is well enough baked to share.) I've been sitting on this for a long time, particularly as my opinion has changed dramatically over the last few years. That I've encountered more crappy code than maintainable, quality code in my career as a software developer only reinforces what I'm about to say. Software development is just a trade for most, and not a huge academic endeavor. For those of you with computer science degrees readying your pitchforks and collecting your algorithm interview questions, let me explain. This is not an assault on your way of life, and if you've been around, you know I'm right about the quality problem. You also know the HR problem is very real, or we wouldn't be paying top dollar for mediocre developers and importing people from all over the world to fill the jobs we can't fill. I'm going to try and outline what I see as some of the problems, and hopefully offer my views on how to address them. The recruiting problem I think a lot of companies are doing it wrong. Over the years, I've had two kinds of interview experiences. The first, and right, kind of experience involves talking about real life achievements, followed by some variation on white boarding in pseudo-code, drafting some basic system architecture, or even sitting down at a comprooder and pecking out some basic code to tackle a real problem. I can honestly say that I've had a job offer for every interview like this, save for one, because the task was to debug something and they didn't like me asking where to look ("everyone else in the company died in a plane crash"). The other interview experience, the wrong one, involves the classic torture test designed to make the candidate feel stupid and do things they never have, and never will do in their job. First they will question you about obscure academic material you've never seen, or don't care to remember. Then they'll ask you to white board some ridiculous algorithm involving prime numbers or some kind of string manipulation no one would ever do. In fact, if you had to do something like this, you'd Google for a solution instead of waste time on a solved problem. Some will tell you that the academic gauntlet interview is useful to see how people respond to pressure, how they engage in complex logic, etc. That might be true, unless of course you have someone who brushed up on the solutions to the silly puzzles, and they're playing you. But here's the real reason why the second experience is wrong: You're evaluating for things that aren't the job. These might have been useful tactics when you had to hire people to write machine language or C++, but in a world dominated by managed code in C#, or Java, people aren't managing memory or trying to be smarter than the compilers. They're using well known design patterns and techniques to deliver software. More to the point, these puzzle gauntlets don't evaluate things that really matter. They don't get into code design, issues of loose coupling and testability, knowledge of the basics around HTTP, or anything else that relates to building supportable and maintainable software. The first situation, involving real life problems, gives you an immediate idea of how the candidate will work out. One of my favorite experiences as an interviewee was with a guy who literally brought his work from that day and asked me how to deal with his problem. I had to demonstrate how I would design a class, make sure the unit testing coverage was solid, etc. I worked at that company for two years. So stop looking for algorithm puzzle crunchers, because a guy who can crush a Fibonacci sequence might also be a guy who writes a class with 5,000 lines of untestable code. Fashion your interview process on ways to reveal a developer who can write supportable and maintainable code. I would even go so far as to let them use the Google. If they want to cut-and-paste code, pass on them, but if they're looking for context or straight class references, hire them, because they're going to be life-long learners. The contractor problem I doubt anyone has ever worked in a place where contractors weren't used. The use of contractors seems like an obvious way to control costs. You can hire someone for just as long as you need them and then let them go. You can even give them the work that no one else wants to do. In practice, most places I've worked have retained and budgeted for the contractor year-round, meaning that the $90+ per hour they're paying (of which half goes to the person) would have been better spent on a full-time person with a $100k salary and benefits. But it's not even the cost that is an issue. It's the quality of work delivered. The accountability of a contractor is totally transient. They only need to deliver for as long as you keep them around, and chances are they'll never again touch the code. There's no incentive for them to get things right, there's little incentive to understand your system or learn anything. At the risk of making an unfair generalization, craftsmanship doesn't matter to most contractors. The education problem I don't know what they teach in college CS courses. I've believed for most of my adult life that a college degree was an essential part of being successful. Of course I would hold that bias, since I did it, and have the paper to show for it in a box somewhere in the basement. My first clue that maybe this wasn't a fully qualified opinion comes from the fact that I double-majored in journalism and radio/TV, not computer science. Eventually I worked with people who skipped college entirely, many of them at Microsoft. Then I worked with people who had a masters degree who sucked at writing code, next to the high school diploma types that rock it every day. I still think there's a lot to be said for the social development of someone who has the on-campus experience, but for software developers, college might not matter. As I mentioned before, most of us are not writing compilers, and we never will. It's actually surprising to find how many people are self-taught in the art of software development, and that should reveal some interesting truths about how we learn. The first truth is that we learn largely out of necessity. There's something that we want to achieve, so we do what I call just-in-time learning to meet those goals. We acquire knowledge when we need it. So what about the gaps in our knowledge? That's where the most valuable education occurs, via our mentors. They're the people we work next to and the people who write blogs. They are critical to our professional development. They don't need to be an encyclopedia of jargon, but they understand the craft. Even at this stage of my career, I probably can't tell you what SOLID stands for, but you can bet that I practice the principles behind that acronym every day. That comes from experience, augmented by my peers. I'm hell bent on passing that experience to others. Process issues If you're a manager type and don't do much in the way of writing code these days (shame on you for not messing around at least), then your job is to isolate your tradespeople from nonsense, while bringing your business into the realm of modern software development. That doesn't mean you slap up a white board with sticky notes and start calling yourself agile, it means getting all of your stakeholders to understand that frequent delivery of quality software is the best way to deal with change and evolving expectations. It also means that you have to play technical overlord to make sure the education and quality issues are dealt with. That's why I make the crack about sticky notes, because without the right technique being practiced among your code monkeys, you're just a guy with sticky notes. You're asking your business to accept frequent and iterative delivery, now make sure that the folks writing the code can handle the same thing. This means unit testing, the right instrumentation, integration tests, automated builds and deployments... all of the stuff that makes it easy to see when change breaks stuff. The prognosis I strongly believe that education is the most important part of what we do. I'm encouraged by things like The Starter League, and it's the kind of thing I'd love to see more of. I would go as far as to say I'd love to start something like this internally at an existing company. Most of all though, I can't emphasize enough how important it is that we mentor each other and share our knowledge. If you have people on your staff who don't want to learn, fire them. Seriously, get rid of them. A few months working with someone really good, who understands the craftsmanship required to build supportable and maintainable code, will change that person forever and increase their value immeasurably.

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• Announcing the Release of Visual Studio 2013 and Great Improvements to ASP.NET and Entity Framework

  - by ScottGu

  Today we released VS 2013 and .NET 4.5.1. These releases include a ton of great improvements, and include some fantastic enhancements to ASP.NET and the Entity Framework.  You can download and start using them now. Below are details on a few of the great ASP.NET, Web Development, and Entity Framework improvements you can take advantage of with this release.  Please visit http://www.asp.net/vnext for additional release notes, documentation, and tutorials. One ASP.NET With the release of Visual Studio 2013, we have taken a step towards unifying the experience of using the different ASP.NET sub-frameworks (Web Forms, MVC, Web API, SignalR, etc), and you can now easily mix and match the different ASP.NET technologies you want to use within a single application. When you do a File-New Project with VS 2013 you’ll now see a single ASP.NET Project option: Selecting this project will bring up an additional dialog that allows you to start with a base project template, and then optionally add/remove the technologies you want to use in it.  For example, you could start with a Web Forms template and add Web API or Web Forms support for it, or create a MVC project and also enable Web Forms pages within it: This makes it easy for you to use any ASP.NET technology you want within your apps, and take advantage of any feature across the entire ASP.NET technology span. Richer Authentication Support The new “One ASP.NET” project dialog also includes a new Change Authentication button that, when pushed, enables you to easily change the authentication approach used by your applications – and makes it much easier to build secure applications that enable SSO from a variety of identity providers.  For example, when you start with the ASP.NET Web Forms or MVC templates you can easily add any of the following authentication options to the application: No Authentication Individual User Accounts (Single Sign-On support with FaceBook, Twitter, Google, and Microsoft ID – or Forms Auth with ASP.NET Membership) Organizational Accounts (Single Sign-On support with Windows Azure Active Directory ) Windows Authentication (Active Directory in an intranet application) The Windows Azure Active Directory support is particularly cool.  Last month we updated Windows Azure Active Directory so that developers can now easily create any number of Directories using it (for free and deployed within seconds).  It now takes only a few moments to enable single-sign-on support within your ASP.NET applications against these Windows Azure Active Directories.  Simply choose the “Organizational Accounts” radio button within the Change Authentication dialog and enter the name of your Windows Azure Active Directory to do this: This will automatically configure your ASP.NET application to use Windows Azure Active Directory and register the application with it.  Now when you run the app your users can easily and securely sign-in using their Active Directory credentials within it – regardless of where the application is hosted on the Internet. For more information about the new process for creating web projects, see Creating ASP.NET Web Projects in Visual Studio 2013. Responsive Project Templates with Bootstrap The new default project templates for ASP.NET Web Forms, MVC, Web API and SPA are built using Bootstrap. Bootstrap is an open source CSS framework that helps you build responsive websites which look great on different form factors such as mobile phones, tables and desktops. For example in a browser window the home page created by the MVC template looks like the following: When you resize the browser to a narrow window to see how it would like on a phone, you can notice how the contents gracefully wrap around and the horizontal top menu turns into an icon: When you click the menu-icon above it expands into a vertical menu – which enables a good navigation experience for small screen real-estate devices: We think Bootstrap will enable developers to build web applications that work even better on phones, tablets and other mobile devices – and enable you to easily build applications that can leverage the rich ecosystem of Bootstrap CSS templates already out there.  You can learn more about Bootstrap here. Visual Studio Web Tooling Improvements Visual Studio 2013 includes a new, much richer, HTML editor for Razor files and HTML files in web applications. The new HTML editor provides a single unified schema based on HTML5. It has automatic brace completion, jQuery UI and AngularJS attribute IntelliSense, attribute IntelliSense Grouping, and other great improvements. For example, typing “ng-“ on an HTML element will show the intellisense for AngularJS: This support for AngularJS, Knockout.js, Handlebars and other SPA technologies in this release of ASP.NET and VS 2013 makes it even easier to build rich client web applications: The screen shot below demonstrates how the HTML editor can also now inspect your page at design-time to determine all of the CSS classes that are available. In this case, the auto-completion list contains classes from Bootstrap’s CSS file. No more guessing at which Bootstrap element names you need to use: Visual Studio 2013 also comes with built-in support for both CoffeeScript and LESS editing support. The LESS editor comes with all the cool features from the CSS editor and has specific Intellisense for variables and mixins across all the LESS documents in the @import chain. Browser Link – SignalR channel between browser and Visual Studio The new Browser Link feature in VS 2013 lets you run your app within multiple browsers on your dev machine, connect them to Visual Studio, and simultaneously refresh all of them just by clicking a button in the toolbar. You can connect multiple browsers (including IE, FireFox, Chrome) to your development site, including mobile emulators, and click refresh to refresh all the browsers all at the same time.  This makes it much easier to easily develop/test against multiple browsers in parallel. Browser Link also exposes an API to enable developers to write Browser Link extensions.  By enabling developers to take advantage of the Browser Link API, it becomes possible to create very advanced scenarios that crosses boundaries between Visual Studio and any browser that’s connected to it. Web Essentials takes advantage of the API to create an integrated experience between Visual Studio and the browser’s developer tools, remote controlling mobile emulators and a lot more. You will see us take advantage of this support even more to enable really cool scenarios going forward. ASP.NET Scaffolding ASP.NET Scaffolding is a new code generation framework for ASP.NET Web applications. It makes it easy to add boilerplate code to your project that interacts with a data model. In previous versions of Visual Studio, scaffolding was limited to ASP.NET MVC projects. With Visual Studio 2013, you can now use scaffolding for any ASP.NET project, including Web Forms. When using scaffolding, we ensure that all required dependencies are automatically installed for you in the project. For example, if you start with an ASP.NET Web Forms project and then use scaffolding to add a Web API Controller, the required NuGet packages and references to enable Web API are added to your project automatically.  To do this, just choose the Add->New Scaffold Item context menu: Support for scaffolding async controllers uses the new async features from Entity Framework 6. ASP.NET Identity ASP.NET Identity is a new membership system for ASP.NET applications that we are introducing with this release. ASP.NET Identity makes it easy to integrate user-specific profile data with application data. ASP.NET Identity also allows you to choose the persistence model for user profiles in your application. You can store the data in a SQL Server database or another data store, including NoSQL data stores such as Windows Azure Storage Tables. ASP.NET Identity also supports Claims-based authentication, where the user’s identity is represented as a set of claims from a trusted issuer. Users can login by creating an account on the website using username and password, or they can login using social identity providers (such as Microsoft Account, Twitter, Facebook, Google) or using organizational accounts through Windows Azure Active Directory or Active Directory Federation Services (ADFS). To learn more about how to use ASP.NET Identity visit http://www.asp.net/identity.  ASP.NET Web API 2 ASP.NET Web API 2 has a bunch of great improvements including: Attribute routing ASP.NET Web API now supports attribute routing, thanks to a contribution by Tim McCall, the author of http://attributerouting.net. With attribute routing you can specify your Web API routes by annotating your actions and controllers like this: OAuth 2.0 support The Web API and Single Page Application project templates now support authorization using OAuth 2.0. OAuth 2.0 is a framework for authorizing client access to protected resources. It works for a variety of clients including browsers and mobile devices. OData Improvements ASP.NET Web API also now provides support for OData endpoints and enables support for both ATOM and JSON-light formats. With OData you get support for rich query semantics, paging, $metadata, CRUD operations, and custom actions over any data source. Below are some of the specific enhancements in ASP.NET Web API 2 OData. Support for $select, $expand, $batch, and $value Improved extensibility Type-less support Reuse an existing model OWIN Integration ASP.NET Web API now fully supports OWIN and can be run on any OWIN capable host. With OWIN integration, you can self-host Web API in your own process alongside other OWIN middleware, such as SignalR. For more information, see Use OWIN to Self-Host ASP.NET Web API. More Web API Improvements In addition to the features above there have been a host of other features in ASP.NET Web API, including CORS support Authentication Filters Filter Overrides Improved Unit Testability Portable ASP.NET Web API Client To learn more go to http://www.asp.net/web-api/ ASP.NET SignalR 2 ASP.NET SignalR is library for ASP.NET developers that dramatically simplifies the process of adding real-time web functionality to your applications. Real-time web functionality is the ability to have server-side code push content to connected clients instantly as it becomes available. SignalR 2.0 introduces a ton of great improvements. We’ve added support for Cross-Origin Resource Sharing (CORS) to SignalR 2.0. iOS and Android support for SignalR have also been added using the MonoTouch and MonoDroid components from the Xamarin library (for more information on how to use these additions, see the article Using Xamarin Components from the SignalR wiki). We’ve also added support for the Portable .NET Client in SignalR 2.0 and created a new self-hosting package. This change makes the setup process for SignalR much more consistent between web-hosted and self-hosted SignalR applications. To learn more go to http://www.asp.net/signalr. ASP.NET MVC 5 The ASP.NET MVC project templates integrate seamlessly with the new One ASP.NET experience and enable you to integrate all of the above ASP.NET Web API, SignalR and Identity improvements. You can also customize your MVC project and configure authentication using the One ASP.NET project creation wizard. The MVC templates have also been updated to use ASP.NET Identity and Bootstrap as well. An introductory tutorial to ASP.NET MVC 5 can be found at Getting Started with ASP.NET MVC 5. This release of ASP.NET MVC also supports several nice new MVC-specific features including: Authentication filters: These filters allow you to specify authentication logic per-action, per-controller or globally for all controllers. Attribute Routing: Attribute Routing allows you to define your routes on actions or controllers. To learn more go to http://www.asp.net/mvc Entity Framework 6 Improvements Visual Studio 2013 ships with Entity Framework 6, which bring a lot of great new features to the data access space: Async and Task<T> Support EF6’s new Async Query and Save support enables you to perform asynchronous data access and take advantage of the Task<T> support introduced in .NET 4.5 within data access scenarios.  This allows you to free up threads that might otherwise by blocked on data access requests, and enable them to be used to process other requests whilst you wait for the database engine to process operations. When the database server responds the thread will be re-queued within your ASP.NET application and execution will continue.  This enables you to easily write significantly more scalable server code. Here is an example ASP.NET WebAPI action that makes use of the new EF6 async query methods: Interception and Logging Interception and SQL logging allows you to view – or even change – every command that is sent to the database by Entity Framework. This includes a simple, human readable log – which is great for debugging – as well as some lower level building blocks that give you access to the command and results. Here is an example of wiring up the simple log to Debug in the constructor of an MVC controller: Custom Code-First Conventions The new Custom Code-First Conventions enable bulk configuration of a Code First model – reducing the amount of code you need to write and maintain. Conventions are great when your domain classes don’t match the Code First conventions. For example, the following convention configures all properties that are called ‘Key’ to be the primary key of the entity they belong to. This is different than the default Code First convention that expects Id or <type name>Id. Connection Resiliency The new Connection Resiliency feature in EF6 enables you to register an execution strategy to handle – and potentially retry – failed database operations. This is especially useful when deploying to cloud environments where dropped connections become more common as you traverse load balancers and distributed networks. EF6 includes a built-in execution strategy for SQL Azure that knows about retryable exception types and has some sensible – but overridable – defaults for the number of retries and time between retries when errors occur. Registering it is simple using the new Code-Based Configuration support: These are just some of the new features in EF6. You can visit the release notes section of the Entity Framework site for a complete list of new features. Microsoft OWIN Components Open Web Interface for .NET (OWIN) defines an open abstraction between .NET web servers and web applications, and the ASP.NET “Katana” project brings this abstraction to ASP.NET. OWIN decouples the web application from the server, making web applications host-agnostic. For example, you can host an OWIN-based web application in IIS or self-host it in a custom process. For more information about OWIN and Katana, see What's new in OWIN and Katana. Summary Today’s Visual Studio 2013, ASP.NET and Entity Framework release delivers some fantastic new features that streamline your web development lifecycle. These feature span from server framework to data access to tooling to client-side HTML development.  They also integrate some great open-source technology and contributions from our developer community. Download and start using them today! Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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• MVVM in Task-It

  As I'm gearing up to write a post about dynamic XAP loading with MEF, I'd like to first talk a bit about MVVM, the Model-View-ViewModel pattern, as I will be leveraging this pattern in my future posts. Download Source Code Why MVVM? Your first question may be, "why do I need this pattern? I've been using a code-behind approach for years and it works fine." Well, you really don't have to make the switch to MVVM, but let me first explain some of the benefits I see for doing so. MVVM Benefits Testability - This is the one you'll probably hear the most about when it comes to MVVM. Moving most of the code from your code-behind to a separate view model class means you can now write unit tests against the view model without any knowledge of a view (UserControl). Multiple UIs - Let's just say that you've created a killer app, it's running in the browser, and maybe you've even made it run out-of-browser. Now what if your boss comes to you and says, "I heard about this new Windows Phone 7 device that is coming out later this year. Can you start porting the app to that device?". Well, now you have to create a new UI (UserControls, etc.) because you have a lot less screen real estate to work with. So what do you do, copy all of your existing UserControls, paste them, rename them, and then start changing the code? Hmm, that doesn't sound so good. But wait, if most of the code that makes your browser-based app tick lives in view model classes, now you can create new view (UserControls) for Windows Phone 7 that reference the same view model classes as your browser-based app. Page state - In Silverlight you're at some point going to be faced with the same issue you dealt with for years in ASP.NET, maintaining page state. Let's say a user hits your Products page, does some stuff (filters record, etc.), then leaves the page and comes back later. It would be best if the Products page was in the same state as when they left it right? Well, if you've thrown away your view (UserControl or Page) and moved off to another part of the UI, when you come back to Products you're probably going to re-instantiate your view...which will put it right back in the state it was when it started. Hmm, not good. Well, with a little help from MEF you can store the state in your view model class, MEF will keep that view model instance hanging around in memory, and then you simply rebind your view to the view model class. I made that sound easy, but it's actually a bit of work to properly store and restore the state. At least it can be done though, which will make your users a lot happier! I'll talk more about this in an upcoming blog post. No event handlers? Another nice thing about MVVM is that you can bind your UserControls to the view model, which may eliminate the need for event handlers in your code-behind. So instead of having a Click handler on a Button (or RadMenuItem), for example, you can now bind your control's Command property to a DelegateCommand in your view model (I'll talk more about Commands in an upcoming post). Instead of having a SelectionChanged event handler on your RadGridView you can now bind its SelectedItem property to a property in your view model, and each time the user clicks a row, the view model property's setter will be called. Now through the magic of binding we can eliminate the need for traditional code-behind based event handlers on our user interface controls, and the best thing is that the view model knows about everything that's going on...which means we can test things without a user interface. The brains of the operation So what we're seeing here is that the view is now just a dumb layer that binds to the view model, and that the view model is in control of just about everything, like what happens when a RadGridView row is selected, or when a RadComboBoxItem is selected, or when a RadMenuItem is clicked. It is also responsible for loading data when the page is hit, as well as kicking off data inserts, updates and deletions. Once again, all of this stuff can be tested without the need for a user interface. If the test works, then it'll work regardless of whether the user is hitting the browser-based version of your app, or the Windows Phone 7 version. Nice! The database Before running the code for this app you will need to create the database. First, create a database called MVVMProject in SQL Server, then run MVVMProject.sql in the MVVMProject/Database directory of your downloaded .zip file. This should give you a Task table with 3 records in it. When you fire up the solution you will also need to update the connection string in web.config to point to your database instead of IBM12\SQLSERVER2008. The code One note about this code is that it runs against the latest Silverlight 4 RC and WCF RIA Services code. Please see my first blog post about updating to the RC bits. Beta to RC - Part 1 At the top of this post is a link to a sample project that demonstrates a sample application with a Tasks page that uses the MVVM pattern. This is a simplified version of how I have implemented the Tasks page in the Task-It application. Youll notice that Tasks.xaml has very little code to it. Just a TextBlock that displays the page title and a ContentControl. <StackPanel>     <TextBlock Text="Tasks" Style="{StaticResource PageTitleStyle}"/>     <Rectangle Style="{StaticResource StandardSpacerStyle}"/>     <ContentControl x:Name="ContentControl1"/> </StackPanel> In List.xaml we have a RadGridView. Notice that the ItemsSource is bound to a property in the view model class call Tasks, SelectedItem is bound to a property in the view model called SelectedItem, and IsBusy is bound to a property in the view model called IsLoading. <Grid>     <telerikGridView:RadGridView ItemsSource="{Binding Tasks}" SelectedItem="{Binding SelectedItem, Mode=TwoWay}"                                  IsBusy="{Binding IsLoading}" AutoGenerateColumns="False" IsReadOnly="True" RowIndicatorVisibility="Collapsed"                IsFilteringAllowed="False" ShowGroupPanel="False">         <telerikGridView:RadGridView.Columns>             <telerikGridView:GridViewDataColumn Header="Name" DataMemberBinding="{Binding Name}" Width="3*"/>             <telerikGridView:GridViewDataColumn Header="Due" DataMemberBinding="{Binding DueDate}" DataFormatString="{}{0:d}" Width="*"/>         </telerikGridView:RadGridView.Columns>     </telerikGridView:RadGridView> </Grid> In Details.xaml we have a Save button that is bound to a property called SaveCommand in our view model. We also have a simple form (Im using a couple of controls here from Silverlight.FX for the form layout, FormPanel and Label simply because they make for a clean XAML layout). Notice that the FormPanel is also bound to the SelectedItem in the view model (the same one that the RadGridView is). The two form controls, the TextBox and RadDatePicker) are bound to the SelectedItem's Name and DueDate properties. These are properties of the Task object that WCF RIA Services creates. <StackPanel>     <Button Content="Save" Command="{Binding SaveCommand}" HorizontalAlignment="Left"/>     <Rectangle Style="{StaticResource StandardSpacerStyle}"/>     <fxui:FormPanel DataContext="{Binding SelectedItem}" Style="{StaticResource FormContainerStyle}">         <fxui:Label Text="Name:"/>         <TextBox Text="{Binding Name, Mode=TwoWay}"/>         <fxui:Label Text="Due:"/>         <telerikInput:RadDatePicker SelectedDate="{Binding DueDate, Mode=TwoWay}"/>     </fxui:FormPanel> </StackPanel> In the code-behind of the Tasks control, Tasks.xaml.cs, I created an instance of the view model class (TasksViewModel) in the constructor and set it as the DataContext for the control. The Tasks page will load one of two child UserControls depending on whether you are viewing the list of tasks (List.xaml) or the form for editing a task (Details.xaml). // Set the DataContext to an instance of the view model class var viewModel = new TasksViewModel(); DataContext = viewModel;   // Child user controls (inherit DataContext from this user control) List = new List(); // RadGridView Details = new Details(); // Form When the page first loads, the List is loaded into the ContentControl. // Show the RadGridView first ContentControl1.Content = List; In the code-behind we also listen for a couple of the view models events. The ItemSelected event will be fired when the user clicks on a record in the RadGridView in the List control. The SaveCompleted event will be fired when the user clicks Save in the Details control (the form). Here the view model is in control, and is letting the view know when something needs to change. // Listeners for the view model's events viewModel.ItemSelected += OnItemSelected; viewModel.SaveCompleted += OnSaveCompleted; The event handlers toggle the view between the RadGridView (List) and the form (Details). void OnItemSelected(object sender, RoutedEventArgs e) {     // Show the form     ContentControl1.Content = Details; }   void OnSaveCompleted(object sender, RoutedEventArgs e) {     // Show the RadGridView     ContentControl1.Content = List; } In TasksViewModel, we instantiate a DataContext object and a SaveCommand in the constructor. DataContext is a WCF RIA Services object that well use to retrieve the list of Tasks and to save any changes to a task. Ill talk more about this and Commands in future post, but for now think of the SaveCommand as an event handler that is called when the Save button in the form is clicked. DataContext = new DataContext(); SaveCommand = new DelegateCommand(OnSave); When the TasksViewModel constructor is called we also make a call to LoadTasks. This sets IsLoading to true (which causes the RadGridViews busy indicator to appear) and retrieves the records via WCF RIA Services.         public LoadOperation<Task> LoadTasks()         {             // Show the loading message             IsLoading = true;             // Get the data via WCF RIA Services. When the call has returned, called OnTasksLoaded.             return DataContext.Load(DataContext.GetTasksQuery(), OnTasksLoaded, false);         } When the data is returned, OnTasksLoaded is called. This sets IsLoading to false (which hides the RadGridViews busy indicator), and fires property changed notifications to the UI to let it know that the IsLoading and Tasks properties have changed. This property changed notification basically tells the UI to rebind. void OnTasksLoaded(LoadOperation<Task> lo) {     // Hide the loading message     IsLoading = false;       // Notify the UI that Tasks and IsLoading properties have changed     this.OnPropertyChanged(p => p.Tasks);     this.OnPropertyChanged(p => p.IsLoading); } Next lets look at the view models SelectedItem property. This is the one thats bound to both the RadGridView and the form. When the user clicks a record in the RadGridView its setter gets called (set a breakpoint and see what I mean). The other code in the setter lets the UI know that the SelectedItem has changed (so the form displays the correct data), and fires the event that notifies the UI that a selection has occurred (which tells the UI to switch from List to Details). public Task SelectedItem {     get { return _selectedItem; }     set     {         _selectedItem = value;           // Let the UI know that the SelectedItem has changed (forces it to re-bind)         this.OnPropertyChanged(p => p.SelectedItem);         // Notify the UI, so it can switch to the Details (form) page         NotifyItemSelected();     } } One last thing, saving the data. When the Save button in the form is clicked it fires the SaveCommand, which calls the OnSave method in the view model (once again, set a breakpoint to see it in action). public void OnSave() {     // Save the changes via WCF RIA Services. When the save is complete, call OnSaveCompleted.     DataContext.SubmitChanges(OnSaveCompleted, null); } In OnSave, we tell WCF RIA Services to submit any changes, which there will be if you changed either the Name or the Due Date in the form. When the save is completed, it calls OnSaveCompleted. This method fires a notification back to the UI that the save is completed, which causes the RadGridView (List) to show again. public virtual void OnSaveCompleted(SubmitOperation so) {     // Clear the item that is selected in the grid (in case we want to select it again)     SelectedItem = null;     // Notify the UI, so it can switch back to the List (RadGridView) page     NotifySaveCompleted(); } 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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