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  • Silverlight 4 Training Kit

    - by Latest Microsoft Blogs
    We recently released a new free Silverlight 4 Training Kit that walks you through building business applications with Silverlight 4.  You can browse the training kit online or alternatively download an entire offline version of the training kit Read More......(read more)

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  • Lessons on Software Development – From Bruce Lee!

    - by Jackie Goldstein
    While we as software developers are used to learning lessons and adopting techniques from other disciplines, it is not often that we look to the martial arts for new ideas on development approaches.  However, this blog post does just that. The author end with the following thought: In the end, follow Bruce Lee’s advice: Examine what others have to offer, take what is useful, and adapt it if necessary. I’ll close with an old quote: “The style doesn’t make the fighter, the fighter makes the style...(read more)

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  • Confused about ASP.NET AJAX, AJAX, jQUERY and javascript

    - by Mr.Y
    Yesterday, I read couple of chapters on ASP.NET Ajax,and jQuery from my ASP.NET 4.0 book and I found those frameworks pretty interesting and decide to learn more about it. Today, I borrow some books from library on AJAX and Javascript. It seems ASP.NET ajax is different from Ajax and jQuery seems like the "new" javascript. Is that means I can skip javascript and learn jQUERY directly? On the other hand, the Ajax(non asp.net) book I borrow from library seems apply to the client side web programming only and looks quite difference from what I learned from ASP.NET AJAX. If I'm a ASP.NET developer I guess I should stick with ASP.NET AJAX instead of client side AJAX right? What about PHP? Is there a "PHP AJAX" similar to ASP.NET AJAX? It's not that I'm "lazy" to learn other tools, but I just want to focus on the right ones. Thx. The more I going deep

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  • Anunciando Windows Azure Mobile Services (Serviços Móveis da Windows Azure)

    - by Leniel Macaferi
    Estou animado para anunciar uma nova capacidade que estamos adicionando à Windows Azure hoje: Windows Azure Mobile Services (Serviços Móveis da Windows Azure) Os Serviços Móveis da Windows Azure tornam incrivelmente fácil conectar um backend da nuvem escalável em suas aplicações clientes e móveis. Estes serviços permitem que você facilmente armazene dados estruturados na nuvem que podem abranger dispositivos e usuários, integrando tais dados com autenticação do usuário. Você também pode enviar atualizações para os clientes através de notificações push. O lançamento de hoje permite que você adicione essas capacidades em qualquer aplicação Windows 8 em literalmente minutos, e fornece uma maneira super produtiva para que você transforme rapidamente suas ideias em aplicações. Também vamos adicionar suporte para permitir esses mesmos cenários para o Windows Phone, iOS e dispositivos Android em breve. Leia este tutorial inicial (em Inglês) que mostra como você pode construir (em menos de 5 minutos) uma simples aplicação Windows 8 "Todo List" (Lista de Tarefas) que é habilitada para a nuvem usando os Serviços Móveis da Windows Azure. Ou assista este vídeo (em Inglês) onde mostro como construí-la passo a passo. Começando Se você ainda não possui uma conta na Windows Azure, você pode se inscrever usando uma assinatura gratuita sem compromisso. Uma vez inscrito, clique na seção "preview features" logo abaixo da tab "account" (conta) no website www.windowsazure.com e ative sua conta para ter acesso ao preview dos "Mobile Services" (Serviços Móveis). Instruções sobre como ativar estes novos recursos podem ser encontradas aqui (em Inglês). Depois de habilitar os Serviços Móveis, entre no Portal da Windows Azure, clique no botão "New" (Novo) e escolha o novo ícone "Mobile Services" (Serviços Móveis) para criar o seu primeiro backend móvel. Uma vez criado, você verá uma página de início rápido como a mostrada a seguir com instruções sobre como conectar o seu serviço móvel a uma aplicação Windows 8 cliente já existente, a qual você já tenha começado a implementar, ou como criar e conectar uma nova aplicação Windows 8 cliente ao backend móvel: Leia este tutorial inicial (em Inglês) com explicações passo a passo sobre como construir (em menos de 5 minutos) uma simples aplicação Windows 8 "Todo List" (Lista de Tarefas) que armazena os dados na Windows Azure. Armazenamento Dados na Nuvem Armazenar dados na nuvem com os Serviços Móveis da Windows Azure é incrivelmente fácil. Quando você cria um Serviço Móvel da Windows Azure, nós automaticamente o associamos com um banco de dados SQL dentro da Windows Azure. O backend do Serviço Móvel da Windows Azure então fornece suporte nativo para permitir que aplicações remotas armazenem e recuperem dados com segurança através dele (usando end-points REST seguros, através de um formato OData baseado em JSON) - sem que você tenha que escrever ou implantar qualquer código personalizado no servidor. Suporte integrado para o gerenciamento do backend é fornecido dentro do Portal da Windows Azure para a criação de novas tabelas, navegação pelos dados, criação de índices, e controle de permissões de acesso. Isto torna incrivelmente fácil conectar aplicações clientes na nuvem, e permite que os desenvolvedores de aplicações desktop que não têm muito conhecimento sobre código que roda no servidor sejam produtivos desde o início. Eles podem se concentrar na construção da experiência da aplicação cliente, tirando vantagem dos Serviços Móveis da Windows Azure para fornecer os serviços de backend da nuvem que se façam necessários.  A seguir está um exemplo de código Windows 8 C#/XAML do lado do cliente que poderia ser usado para consultar os dados de um Serviço Móvel da Windows Azure. Desenvolvedores de aplicações que rodam no cliente e que usam C# podem escrever consultas como esta usando LINQ e objetos fortemente tipados POCO, os quais serão mais tarde traduzidos em consultas HTTP REST que são executadas em um Serviço Móvel da Windows Azure. Os desenvolvedores não precisam escrever ou implantar qualquer código personalizado no lado do servidor para permitir que o código do lado do cliente mostrado a seguir seja executado de forma assíncrona preenchendo a interface (UI) do cliente: Como os Serviços Móveis fazem parte da Windows Azure, os desenvolvedores podem escolher mais tarde se querem aumentar ou estender sua solução adicionando funcionalidades no lado do servidor bem como lógica de negócio mais avançada, se quiserem. Isso proporciona o máximo de flexibilidade, e permite que os desenvolvedores ampliem suas soluções para atender qualquer necessidade. Autenticação do Usuário e Notificações Push Os Serviços Móveis da Windows Azure também tornam incrivelmente fácil integrar autenticação/autorização de usuários e notificações push em suas aplicações. Você pode usar esses recursos para habilitar autenticação e controlar as permissões de acesso aos dados que você armazena na nuvem de uma maneira granular. Você também pode enviar notificações push para os usuários/dispositivos quando os dados são alterados. Os Serviços Móveis da Windows Azure suportam o conceito de "scripts do servidor" (pequenos pedaços de script que são executados no servidor em resposta a ações), os quais tornam a habilitação desses cenários muito fácil. A seguir estão links para alguns tutoriais (em Inglês) no formato passo a passo para cenários comuns de autenticação/autorização/push que você pode utilizar com os Serviços Móveis da Windows Azure e aplicações Windows 8: Habilitando Autenticação do Usuário Autorizando Usuários  Começando com Push Notifications Push Notifications para múltiplos Usuários Gerencie e Monitore seu Serviço Móvel Assim como todos os outros serviços na Windows Azure, você pode monitorar o uso e as métricas do backend de seu Serviço Móvel usando a tab "Dashboard" dentro do Portal da Windows Azure. A tab Dashboard fornece uma visão de monitoramento que mostra as chamadas de API, largura de banda e ciclos de CPU do servidor consumidos pelo seu Serviço Móvel da Windows Azure. Você também usar a tab "Logs" dentro do portal para ver mensagens de erro.  Isto torna fácil monitorar e controlar como sua aplicação está funcionando. Aumente a Capacidade de acordo com o Crescimento do Seu Negócio Os Serviços Móveis da Windows Azure agora permitem que cada cliente da Windows Azure crie e execute até 10 Serviços Móveis de forma gratuita, em um ambiente de hospedagem compartilhado com múltiplos banco de dados (onde o backend do seu Serviço Móvel será um dos vários aplicativos sendo executados em um conjunto compartilhado de recursos do servidor). Isso fornece uma maneira fácil de começar a implementar seus projetos sem nenhum custo algum (nota: cada conta gratuita da Windows Azure também inclui um banco de dados SQL de 1GB que você pode usar com qualquer número de aplicações ou Serviços Móveis da Windows Azure). Se sua aplicação cliente se tornar popular, você pode clicar na tab "Scale" (Aumentar Capacidade) do seu Serviço Móvel e mudar de "Shared" (Compartilhado) para o modo "Reserved" (Reservado). Isso permite que você possa isolar suas aplicações de maneira que você seja o único cliente dentro de uma máquina virtual. Isso permite que você dimensione elasticamente a quantidade de recursos que suas aplicações consomem - permitindo que você aumente (ou diminua) sua capacidade de acordo com o tráfego de dados: Com a Windows Azure você paga por capacidade de processamento por hora - o que te permite dimensionar para cima e para baixo seus recursos para atender apenas o que você precisa. Isso permite um modelo super flexível que é ideal para novos cenários de aplicações móveis, bem como para novas empresas que estão apenas começando. Resumo Eu só toquei na superfície do que você pode fazer com os Serviços Móveis da Windows Azure - há muito mais recursos para explorar. Com os Serviços Móveis da Windows Azure, você será capaz de construir cenários de aplicações móveis mais rápido do que nunca, permitindo experiências de usuário ainda melhores - conectando suas aplicações clientes na nuvem. Visite o centro de desenvolvimento dos Serviços Móveis da Windows Azure (em Inglês) para aprender mais, e construa sua primeira aplicação Windows 8 conectada à Windows Azure hoje. E leia este tutorial inicial (em Inglês) com explicações passo a passo que mostram como você pode construir (em menos de 5 minutos) uma simples aplicação Windows 8 "Todo List" (Lista de Tarefas) habilitada para a nuvem usando os Serviços Móveis da Windows Azure. Espero que ajude, - Scott P.S. Além do blog, eu também estou utilizando o Twitter para atualizações rápidas e para compartilhar links. Siga-me em: twitter.com/ScottGu Texto traduzido do post original por Leniel Macaferi.

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  • Automatic Properties, Collection Initializers, and Implicit Line Continuation support with VB 2010

    - by ScottGu
    [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] This is the eighteenth in a series of blog posts I’m doing on the upcoming VS 2010 and .NET 4 release. A few days ago I blogged about two new language features coming with C# 4.0: optional parameters and named arguments.  Today I’m going to post about a few of my favorite new features being added to VB with VS 2010: Auto-Implemented Properties, Collection Initializers, and Implicit Line Continuation support. Auto-Implemented Properties Prior to VB 2010, implementing properties within a class using VB required you to explicitly declare the property as well as implement a backing field variable to store its value.  For example, the code below demonstrates how to implement a “Person” class using VB 2008 that exposes two public properties - “Name” and “Age”:   While explicitly declaring properties like above provides maximum flexibility, I’ve always found writing this type of boiler-plate get/set code tedious when you are simply storing/retrieving the value from a field.  You can use VS code snippets to help automate the generation of it – but it still generates a lot of code that feels redundant.  C# 2008 introduced a cool new feature called automatic properties that helps cut down the code quite a bit for the common case where properties are simply backed by a field.  VB 2010 also now supports this same feature.  Using the auto-implemented properties feature of VB 2010 we can now implement our Person class using just the code below: When you declare an auto-implemented property, the VB compiler automatically creates a private field to store the property value as well as generates the associated Get/Set methods for you.  As you can see above – the code is much more concise and easier to read. The syntax supports optionally initializing the properties with default values as well if you want to: You can learn more about VB 2010’s automatic property support from this MSDN page. Collection Initializers VB 2010 also now supports using collection initializers to easily create a collection and populate it with an initial set of values.  You identify a collection initializer by declaring a collection variable and then use the From keyword followed by braces { } that contain the list of initial values to add to the collection.  Below is a code example where I am using the new collection initializer feature to populate a “Friends” list of Person objects with two people, and then bind it to a GridView control to display on a page: You can learn more about VB 2010’s collection initializer support from this MSDN page. Implicit Line Continuation Support Traditionally, when a statement in VB has been split up across multiple lines, you had to use a line-continuation underscore character (_) to indicate that the statement wasn’t complete.  For example, with VB 2008 the below LINQ query needs to append a “_” at the end of each line to indicate that the query is not complete yet: The VB 2010 compiler and code editor now adds support for what is called “implicit line continuation support” – which means that it is smarter about auto-detecting line continuation scenarios, and as a result no longer needs you to explicitly indicate that the statement continues in many, many scenarios.  This means that with VB 2010 we can now write the above code with no “_” at all: The implicit line continuation feature also works well when editing XML Literals within VB (which is pretty cool). You can learn more about VB 2010’s Implicit Line Continuation support and many of the scenarios it supports from this MSDN page (scroll down to the “Implicit Line Continuation” section to find details). Summary The above three VB language features are but a few of the new language and code editor features coming with VB 2010.  Visit this site to learn more about some of the other VB language features coming with the release.  Also subscribe to the VB team’s blog to learn more and stay up-to-date with the posts they the team regularly publishes. Hope this helps, Scott

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  • using ‘using’ and scope. Not try finally!

    - by Edward Boyle
    An object that implements IDisposable has, you guessed it, a Dispose() method. In the code you write you should both declare and instantiate any object that implements IDisposable with the using statement. The using statement allows you to set the scope of an object and when your code exits that scope, the object will be disposed of. Note that when an exception occurs, this will pull your code out of scope, so it still forces a Dispose() using (mObject o = new mObject()) { // do stuff } //<- out of Scope, object is disposed. // Note that you can also use multiple objects using // the using statement if of the same type: using (mObject o = new mObject(), o2 = new mObject(), o3 = new mObject()) { // do stuff } //<- out of Scope, objects are disposed. What about try{ }finally{}? It is not needed when you use the using statement. Additionally, using is preferred, Microsoft’s own documents put it this way: As a rule, when you use an IDisposable object, you should declare and instantiate it in a using statement. When I started out in .NET I had a very bad habit of not using the using statement. As a result I ran into what many developers do: #region BAD CODE - DO NOT DO try { mObject o = new mObject(); //do stuff } finally { o.Dispose(); // error - o is out of scope, no such object. } // and here is what I find on blogs all over the place as a solution // pox upon them for creating bad habits. mObject o = new mObject(); try { //do stuff } finally { o.Dispose(); } #endregion So when should I use the using statement? Very simple rule, if an object implements IDisposable, use it. This of course does not apply if the object is going to be used as a global object outside of a method. If that is the case, don’t forget to dispose of the object in code somewhere. It should be made clear that using the try{}finally{} code block is not going to break your code, nor cause memory leaks. It is perfectly acceptable coding practice, just not best coding practice in C#. This is how VB.NET developers must code, as there is no using equivalent for them to use.

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  • Code snippets for ASP.NET MVC2 in VS 2010

    - by rajbk
    VS 2010 comes with ready made snippets which helps you save time while coding. You insert a snippet by typing the name of the code snippet and hitting the Tab key twice. You can also use the following method if you wish to see a listing of snippets available. Press Ctrl + K, Ctrl + X Select ASP.NET MVC2 with the arrow keys and hit enter to see a list of snippets available.   The MVC related snippets you get out of the box (for C#) are listed below: HTML actionlink Markup snippet for an ASP.NET MVC action link helper <%= Html.ActionLink("linktext", "actionname") %>   beginformajaxcs Markup snippet for an ASP.NET MVC AJAX-enabled form helper in C# <% using (Ajax.BeginForm("actionname", new AjaxOptions {UpdateTargetId= "elementid" })) { %> <% } %>   beginformcs Markup snippet for an ASP.NET MVC form helper in C# <% using (Html.BeginForm()) { %> <% } %>   displayforcs Markup snippet for an ASP.NET MVC templated helper. <%= Html.DisplayFor(x => x.Property) %>   editorforcs Markup snippet for an ASP.NET MVC templated helper. <%= Html.EditorFor(x => x.Property) %>   foreachcs Markup snippet for an ASP.NET MVC foreach statement in C# <% foreach (var item in collection) { %> <% } %>   ifcs Markup snippet for a code-nugget if else statement in C# <% if (true) { %> <% } %>   ifelsecs Markup snippet for a code-nugget if else statement in C# <% if (true) { %> <% } else { %> <% } %>   renderpartialcs Markup snippet for an ASP.NET MVC partial view rendering in C# <% Html.RenderPartial("viewname"); %>   textboxmvc Markup snippet for an ASP.NET MVC textbox helper <%= Html.TextBox("name") %>   validationsummarymvc Markup snippet for an ASP.NET MVC validation summary helper <%= Html.ValidationSummary() %> CS mvcaction Code snippet for an action. public ActionResult Action() {     return View(); }   mvcpostaction Code snippet for an action via http post. [HttpPost] public ActionResult Action() {     return View(); }   Enjoy!

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  • Display ‘–Select–’ in an ASP.NET DropDownList

    - by Ken Cox [MVP]
    A purchaser of my book writes: “I would like a drop down list to display the text: "-Select-" initially instead of the first value of the data it is bound to.” Here you go…   <%@ Page Language="VB" %> <script runat="server">     Protected Sub Page_Load(ByVal sender As Object, _                            ...(read more)

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  • Problem converting FBX file into XNB

    - by Dado
    I create a Monogame Content Project to convert assets into XNB. For FBX file without texture there is no problem: the file is correctly converted and when I load XNB into my project everything is ok. The problem occours when i have associated to fbx file a texture map: in this case both FBX and PNG files are converted to XNB but when i try to load these XNB files into my project the following problem occours: "ContentLoadException: Could not load Models/maze1 asset as a non-content file!" Note: maze1 is the XNB file that was converted from FBX. How can I solve this problem? Thank you in advance

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  • Reading data from an Entity Framework data model through a WCF Data Service

    - by nikolaosk
    This is going to be the fourth post of a series of posts regarding ASP.Net and the Entity Framework and how we can use Entity Framework to access our datastore. You can find the first one here , the second one here and the third one here . I have a post regarding ASP.Net and EntityDataSource. You can read it here .I have 3 more posts on Profiling Entity Framework applications. You can have a look at them here , here and here . Microsoft with .Net 3.0 Framework, introduced WCF. WCF is Microsoft's...(read more)

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  • Wpf vs WinForms for a vb programmer? [closed]

    - by Jeroen
    I am asked by a client to develop an application that is basically a screen on which the user can choose several items to pass the time (used in holding cells in mental hospitals for example). The baisc idea is as follows: TV (choosing this will provide the user with a number of TV streams from the interweb) Radio (...) Games (serveral flash games, also from the interweb) Music (play local music or streams) Draw something (not the game) Create an email Choose lighting settings for the room etc. etc. I am torn between WinForms and WPF for this project. It seems that WPF is the way to go since there is quite a bit of rich media involved but I have a 15 year VB background. The project obviously has a dead line and certain budget that I cannot cross and if I can avoid starting from scratch with some thing that will be nice. Is WPF worth it in this particular case or can I use WinForms with the incorperation of WPF controls? I would very much like to hear your thoughts/comments/suggestions!

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  • Interface contracts – forcing code contracts through interfaces

    - by DigiMortal
    Sometimes we need a way to make different implementations of same interface follow same rules. One option is to duplicate contracts to all implementation but this is not good option because we have duplicated code then. The other option is to force contracts to all implementations at interface level. In this posting I will show you how to do it using interface contracts and contracts class. Using code from previous example about unit testing code with code contracts I will go further and force contracts at interface level. Here is the code from previous example. Take a careful look at it because I will talk about some modifications to this code soon. public interface IRandomGenerator {     int Next(int min, int max); }   public class RandomGenerator : IRandomGenerator {     private Random _random = new Random();       public int Next(int min, int max)     {         return _random.Next(min, max);     } }    public class Randomizer {     private IRandomGenerator _generator;       private Randomizer()     {         _generator = new RandomGenerator();     }       public Randomizer(IRandomGenerator generator)     {         _generator = generator;     }       public int GetRandomFromRangeContracted(int min, int max)     {         Contract.Requires<ArgumentOutOfRangeException>(             min < max,             "Min must be less than max"         );           Contract.Ensures(             Contract.Result<int>() >= min &&             Contract.Result<int>() <= max,             "Return value is out of range"         );           return _generator.Next(min, max);     } } If we look at the GetRandomFromRangeContracted() method we can see that contracts set in this method are applicable to all implementations of IRandomGenerator interface. Although we can write new implementations as we want these implementations need exactly the same contracts. If we are using generators somewhere else then code contracts are not with them anymore. To solve the problem we will force code contracts at interface level. NB! To make the following code work you must enable Contract Reference Assembly building from project settings. Interface contracts and contracts class Interface contains no code – only definitions of members that implementing type must have. But code contracts must be defined in body of member they are part of. To get over this limitation, code contracts are defined in separate contracts class. Interface is bound to this class by special attribute and contracts class refers to interface through special attribute. Here is the IRandomGenerator with contracts and contracts class. Also I write simple fake so we can test contracts easily based only on interface mock. [ContractClass(typeof(RandomGeneratorContracts))] public interface IRandomGenerator {     int Next(int min, int max); }   [ContractClassFor(typeof(IRandomGenerator))] internal sealed class RandomGeneratorContracts : IRandomGenerator {     int IRandomGenerator.Next(int min, int max)     {         Contract.Requires<ArgumentOutOfRangeException>(                 min < max,                 "Min must be less than max"             );           Contract.Ensures(             Contract.Result<int>() >= min &&             Contract.Result<int>() <= max,             "Return value is out of range"         );           return default(int);     } }   public class RandomFake : IRandomGenerator {     private int _testValue;       public RandomGen(int testValue)     {         _testValue = testValue;     }       public int Next(int min, int max)     {         return _testValue;     } } To try out these changes use the following code. var gen = new RandomFake(3);   try {     gen.Next(10, 1); } catch(Exception ex) {     Debug.WriteLine(ex.Message); }   try {     gen.Next(5, 10); } catch(Exception ex) {     Debug.WriteLine(ex.Message); } Now we can force code contracts to all types that implement our IRandomGenerator interface and we must test only the interface to make sure that contracts are defined correctly.

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  • Free .NET Training at DevCare in Dallas...

    - by [email protected]
    Come take an early look at the debugging experience in VS 2010 this Friday (3/25/2010) at TekFocus in Dallas, at the InfoMart, at 9 AM: In this session, we’ll … Dive deep into the new IntelliTrace (formerly, historical debugging) feature, which enables you to step back in time within your debugging session and inspect or re-execute code, without having to restart your application See how to manage large numbers of breakpoints with labeling, searching and filtering Extend “data tips” by adding comments, notes and strategically “pinning” these resources to maintain their visibility throughout your session Demonstrate “collaborative debugging,“ by debugging a portion of an application and then exporting breakpoints and labeled data tips, so that others can leverage your effort, without having to start over Leverage these new debugging features in applications built in earlier versions of the .NET Framework through the MultiTargeting features available in VS 2010 You’ll walk-away with a clear understanding of how you can use this upcoming technology to vastly increase your productivity and build better software.Register to attend ==>  http://www.dallasdevcares.com/upcoming-sessions/ DevCares is a monthly series of FREE half-day events sponsored by TekFocus and Microsoft. Targeted specifically at developers, the content is presented by experts on a variety of .NET topics. These briefings include expert testimonials, working demos and sample code designed to help you get the most out of application development with .NET. Events are held on the last Friday of each month at the TekFocus offices in the Infomart near downtown Dallas.TekFocus is a full-service technology training provider with a core business delivering Microsoft-certified technical training and product skills enhancements to customers worldwide    

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  • Code Contracts: Hiding ContractException

    - by DigiMortal
    It’s time to move on and improve my randomizer I wrote for an example of static checking of code contracts. In this posting I will modify contracts and give some explanations about pre-conditions and post-conditions. Also I will show you how to avoid ContractExceptions and how to replace them with your own exceptions. As a first thing let’s take a look at my randomizer. public class Randomizer {     public static int GetRandomFromRange(int min, int max)     {         var rnd = new Random();         return rnd.Next(min, max);     }       public static int GetRandomFromRangeContracted(int min, int max)     {         Contract.Requires(min < max, "Min must be less than max");           var rnd = new Random();         return rnd.Next(min, max);     } } We have some problems here. We need contract for method output and we also need some better exception handling mechanism. As ContractException as type is hidden from us we have to switch from ContractException to some other Exception type that we can catch. Adding post-condition Pre-conditions are contracts for method’s input interface. Read it as follows: pre-conditions make sure that all conditions for method’s successful run are met. Post-conditions are contracts for output interface of method. So, post-conditions are for output arguments and return value. My code misses the post-condition that checks return value. Return value in this case must be greater or equal to minimum value and less or equal to maximum value. To make sure that method can run only the correct value I added call to Contract.Ensures() method. public static int GetRandomFromRangeContracted(int min, int max) {     Contract.Requires(min < max, "Min must be less than max");       Contract.Ensures(         Contract.Result<int>() >= min &&         Contract.Result<int>() <= max,         "Return value is out of range"     );       var rnd = new Random();     return rnd.Next(min, max); } I think that the line I added does not need any further comments. Avoiding ContractException for input interface ContractException lives in hidden namespace and we cannot see it at design time. But it is common exception type for all contract exceptions that we do not switch over to some other type. The case of Contract.Requires() method is simple: we can tell it what kind of exception we need if something goes wrong with contract it ensures. public static int GetRandomFromRangeContracted(int min, int max) {     Contract.Requires<ArgumentOutOfRangeException>(         min < max,         "Min must be less than max"     );       Contract.Ensures(         Contract.Result<int>() >= min &&         Contract.Result<int>() <= max,         "Return value is out of range"     );       var rnd = new Random();     return rnd.Next(min, max); } Now, if we violate the input interface contract giving min value that is not less than max value we get ArgumentOutOfRangeException. Avoiding ContractException for output interface Output interface is more complex to control. We cannot give exception type there and hope that this type of exception will be thrown if something goes wrong. Instead we have to use delegate that gathers information about problem and throws the exception we expect to be thrown. From documentation you can find the following example about the delegate I mentioned. Contract.ContractFailed += (sender, e) => {     e.SetHandled();     e.SetUnwind(); // cause code to abort after event     Assert.Fail(e.FailureKind.ToString() + ":" + e.DebugMessage); }; We can use this delegate to throw the Exception. Let’s move the code to separate method too. Here is our method that uses now ContractException hiding. public static int GetRandomFromRangeContracted(int min, int max) {     Contract.Requires(min < max, "Min must be less than max");       Contract.Ensures(         Contract.Result<int>() >= min &&         Contract.Result<int>() <= max,         "Return value is out of range"     );     Contract.ContractFailed += Contract_ContractFailed;       var rnd = new Random();     return rnd.Next(min, max)+1000; } And here is the delegate that creates exception. public static void Contract_ContractFailed(object sender,     ContractFailedEventArgs e) {     e.SetHandled();     e.SetUnwind();       throw new Exception(e.FailureKind.ToString() + ":" + e.Message); } Basically we can do in this delegate whatever we like to do with output interface errors. We can even introduce our own contract exception type. As you can see later then ContractFailed event is very useful at unit testing.

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  • Optional Parameters and Named Arguments in C# 4 (and a cool scenario w/ ASP.NET MVC 2)

    - by ScottGu
    [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] This is the seventeenth in a series of blog posts I’m doing on the upcoming VS 2010 and .NET 4 release. Today’s post covers two new language feature being added to C# 4.0 – optional parameters and named arguments – as well as a cool way you can take advantage of optional parameters (both in VB and C#) with ASP.NET MVC 2. Optional Parameters in C# 4.0 C# 4.0 now supports using optional parameters with methods, constructors, and indexers (note: VB has supported optional parameters for awhile). Parameters are optional when a default value is specified as part of a declaration.  For example, the method below takes two parameters – a “category” string parameter, and a “pageIndex” integer parameter.  The “pageIndex” parameter has a default value of 0, and as such is an optional parameter: When calling the above method we can explicitly pass two parameters to it: Or we can omit passing the second optional parameter – in which case the default value of 0 will be passed:   Note that VS 2010’s Intellisense indicates when a parameter is optional, as well as what its default value is when statement completion is displayed: Named Arguments and Optional Parameters in C# 4.0 C# 4.0 also now supports the concept of “named arguments”.  This allows you to explicitly name an argument you are passing to a method – instead of just identifying it by argument position.  For example, I could write the code below to explicitly identify the second argument passed to the GetProductsByCategory method by name (making its usage a little more explicit): Named arguments come in very useful when a method supports multiple optional parameters, and you want to specify which arguments you are passing.  For example, below we have a method DoSomething that takes two optional parameters: We could use named arguments to call the above method in any of the below ways: Because both parameters are optional, in cases where only one (or zero) parameters is specified then the default value for any non-specified arguments is passed. ASP.NET MVC 2 and Optional Parameters One nice usage scenario where we can now take advantage of the optional parameter support of VB and C# is with ASP.NET MVC 2’s input binding support to Action methods on Controller classes. For example, consider a scenario where we want to map URLs like “Products/Browse/Beverages” or “Products/Browse/Deserts” to a controller action method.  We could do this by writing a URL routing rule that maps the URLs to a method like so: We could then optionally use a “page” querystring value to indicate whether or not the results displayed by the Browse method should be paged – and if so which page of the results should be displayed.  For example: /Products/Browse/Beverages?page=2. With ASP.NET MVC 1 you would typically handle this scenario by adding a “page” parameter to the action method and make it a nullable int (which means it will be null if the “page” querystring value is not present).  You could then write code like below to convert the nullable int to an int – and assign it a default value if it was not present in the querystring: With ASP.NET MVC 2 you can now take advantage of the optional parameter support in VB and C# to express this behavior more concisely and clearly.  Simply declare the action method parameter as an optional parameter with a default value: C# VB If the “page” value is present in the querystring (e.g. /Products/Browse/Beverages?page=22) then it will be passed to the action method as an integer.  If the “page” value is not in the querystring (e.g. /Products/Browse/Beverages) then the default value of 0 will be passed to the action method.  This makes the code a little more concise and readable. Summary There are a bunch of great new language features coming to both C# and VB with VS 2010.  The above two features (optional parameters and named parameters) are but two of them.  I’ll blog about more in the weeks and months ahead. If you are looking for a good book that summarizes all the language features in C# (including C# 4.0), as well provides a nice summary of the core .NET class libraries, you might also want to check out the newly released C# 4.0 in a Nutshell book from O’Reilly: It does a very nice job of packing a lot of content in an easy to search and find samples format. Hope this helps, Scott

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  • EF 4’s PluralizationService Class: A Singularly Impossible Plurality

    - by Ken Cox [MVP]
    Entity Framework’s new 4.0 designer does its best to generate correct plural and singular forms of object names. This magic is done through the PluralizationService Class found in the System.Data.Entity.Design.PluralizationServices namespace and in the System.Data.Entity.Design.dll assembly. [Before you ask… Yes, I’ll post my example page, the service, and the project source code as soon as my ISP makes ASP.NET 4 RTM available. Stay tuned.] Anyone who speaks English is brutally aware of the ridiculous...(read more)

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  • Permanently redirect your asp.net pages in ASP.Net 4.0

    - by nikolaosk
    Hello all, In this post, I would like to talk about a new method of the Response object that comes with ASP.Net 4.0. The name of the method is RedirectPermanent . Let's talk a bit about 301 redirection and permanent redirection.301 redirect is the most efficient and Search Engine Friendly method for webpage redirection. Let's imagine that we have this scenario. This is a very common scenario. We have redesigned and move folders to some pages that have high search engine rankings. We do not want to...(read more)

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