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  • Microsoft’s Contribution to jQuery – Client Templating

    - by joelvarty
    I am interested to see the community’s response to Microsoft’s contributions to jQuery.  I have been using jTemplates on and off in my apps for a while, but I will certainly check out the new templating plugins put forth by MS and explained here by Scott Guthrie. It may be that some are against the very idea of a company like Microsoft being involved with jQuery, and Scott explains the process with the following: “jQuery has a fantastic developer community, and a very open way to propose suggestions and make contributions.  Microsoft is following the same process to contribute to jQuery as any other member of the community.” I think we can take this in one of two ways:  It’s great that Microsoft sees themselves as a part of a greater community that they can support. It’s the first step in Microsoft’s attempt to usurp the community and have greater control over the web, it’s standards, and it’s developer community. Personally, I believe Microsoft sees the world (and the web) differently from how they did back when IE had more than %80 of the browser market.  Now, in order to keep it’s development products relevant, they are pushing Asp.Net (as they have been for a few years) towards a more open strategy that’s more “web-like” in my opinion. These contributions to jQuery are a good thing, I think.  Now, let’s go try out these new plug-ins and see if they stack up… more later - joel

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  • Html Agility Pack for Reading “Real World” HTML

    - by WeigeltRo
    In an ideal world, all data you need from the web would be available via well-designed services. In the real world you sometimes have to scrape the data off a web page. Ugly, dirty – but if you really want that data, you have no choice. Just don’t write (yet another) HTML parser. I stumbled across the Html Agility Pack (HAP) a long time ago, but just now had the need for a robust way to read HTML. A quote from the website: This is an agile HTML parser that builds a read/write DOM and supports plain XPATH or XSLT (you actually don't HAVE to understand XPATH nor XSLT to use it, don't worry...). It is a .NET code library that allows you to parse "out of the web" HTML files. The parser is very tolerant with "real world" malformed HTML. The object model is very similar to what proposes System.Xml, but for HTML documents (or streams). Using the HAP was a simple matter of getting the Nuget package, taking a look at the example and dusting off some of my XPath knowledge from years ago. The documentation on the Codeplex site is non-existing, but if you’ve queried a DOM or used XPath or XSLT before you shouldn’t have problems finding your way around using Intellisense (ReSharper tip: Press Ctrl+Shift+F1 on class members for reading the full doc comments).

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  • MonoDroid Article in Visual Studio Magazine

    - by Wallym
    The February edition of Visual Studio magazine is now online.  In it, my article regarding MonoDroid, the implementation of C# and .NET for Android devices, is online.  I can't thank Michael Desmond enough for the opportunity.  Its fitting now that Android is the most popular smartphone platform.  This article is available online at: Intro to MonoDroid Part 1. Intro to MonoDroid Part 2. Along with the article, check out this short video that I did regarding MonoDroid on the Mac. The article(s) were written based on MonoDroid Preview 9.1, so there are a few updates necessary, but I think this gets the basics out.  I hope you enjoy the article(s). And yes, we're still working on our book on MonoDroid.  I've got a great author group and am excited about the book. If you get a chance, come to AnDevCon in San Francisco in March.  I'll be presenting on MonoDroid there.

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  • April 2013 Release of the Ajax Control Toolkit

    - by Stephen.Walther
    I’m excited to announce the April 2013 release of the Ajax Control Toolkit. For this release, we focused on improving two controls: the AjaxFileUpload and the MaskedEdit controls. You can download the latest release from CodePlex at http://AjaxControlToolkit.CodePlex.com or, better yet, you can execute the following NuGet command within Visual Studio 2010/2012: There are three builds of the Ajax Control Toolkit: .NET 3.5, .NET 4.0, and .NET 4.5. A Better AjaxFileUpload Control We completely rewrote the AjaxFileUpload control for this release. We had two primary goals. First, we wanted to support uploading really large files. In particular, we wanted to support uploading multi-gigabyte files such as video files or application files. Second, we wanted to support showing upload progress on as many browsers as possible. The previous version of the AjaxFileUpload could show upload progress when used with Google Chrome or Mozilla Firefox but not when used with Apple Safari or Microsoft Internet Explorer. The new version of the AjaxFileUpload control shows upload progress when used with any browser. Using the AjaxFileUpload Control Let me walk-through using the AjaxFileUpload in the most basic scenario. And then, in following sections, I can explain some of its more advanced features. Here’s how you can declare the AjaxFileUpload control in a page: <ajaxToolkit:ToolkitScriptManager runat="server" /> <ajaxToolkit:AjaxFileUpload ID="AjaxFileUpload1" AllowedFileTypes="mp4" OnUploadComplete="AjaxFileUpload1_UploadComplete" runat="server" /> The exact appearance of the AjaxFileUpload control depends on the features that a browser supports. In the case of Google Chrome, which supports drag-and-drop upload, here’s what the AjaxFileUpload looks like: Notice that the page above includes two Ajax Control Toolkit controls: the AjaxFileUpload and the ToolkitScriptManager control. You always need to include the ToolkitScriptManager with any page which uses Ajax Control Toolkit controls. The AjaxFileUpload control declared in the page above includes an event handler for its UploadComplete event. This event handler is declared in the code-behind page like this: protected void AjaxFileUpload1_UploadComplete(object sender, AjaxControlToolkit.AjaxFileUploadEventArgs e) { // Save uploaded file to App_Data folder AjaxFileUpload1.SaveAs(MapPath("~/App_Data/" + e.FileName)); } This method saves the uploaded file to your website’s App_Data folder. I’m assuming that you have an App_Data folder in your project – if you don’t have one then you need to create one or you will get an error. There is one more thing that you must do in order to get the AjaxFileUpload control to work. The AjaxFileUpload control relies on an HTTP Handler named AjaxFileUploadHandler.axd. You need to declare this handler in your application’s root web.config file like this: <configuration> <system.web> <compilation debug="true" targetFramework="4.5" /> <httpRuntime targetFramework="4.5" maxRequestLength="42949672" /> <httpHandlers> <add verb="*" path="AjaxFileUploadHandler.axd" type="AjaxControlToolkit.AjaxFileUploadHandler, AjaxControlToolkit"/> </httpHandlers> </system.web> <system.webServer> <validation validateIntegratedModeConfiguration="false"/> <handlers> <add name="AjaxFileUploadHandler" verb="*" path="AjaxFileUploadHandler.axd" type="AjaxControlToolkit.AjaxFileUploadHandler, AjaxControlToolkit"/> </handlers> <security> <requestFiltering> <requestLimits maxAllowedContentLength="4294967295"/> </requestFiltering> </security> </system.webServer> </configuration> Notice that the web.config file above also contains configuration settings for the maxRequestLength and maxAllowedContentLength. You need to assign large values to these configuration settings — as I did in the web.config file above — in order to accept large file uploads. Supporting Chunked File Uploads Because one of our primary goals with this release was support for large file uploads, we added support for client-side chunking. When you upload a file using a browser which fully supports the HTML5 File API — such as Google Chrome or Mozilla Firefox — then the file is uploaded in multiple chunks. You can see chunking in action by opening F12 Developer Tools in your browser and observing the Network tab: Notice that there is a crazy number of distinct post requests made (about 360 distinct requests for a 1 gigabyte file). Each post request looks like this: http://localhost:24338/AjaxFileUploadHandler.axd?contextKey={DA8BEDC8-B952-4d5d-8CC2-59FE922E2923}&fileId=B7CCE31C-6AB1-BB28-2940-49E0C9B81C64 &fileName=Sita_Sings_the_Blues_480p_2150kbps.mp4&chunked=true&firstChunk=false Each request posts another chunk of the file being uploaded. Notice that the request URL includes a chunked=true parameter which indicates that the browser is breaking the file being uploaded into multiple chunks. Showing Upload Progress on All Browsers The previous version of the AjaxFileUpload control could display upload progress only in the case of browsers which fully support the HTML5 File API. The new version of the AjaxFileUpload control can display upload progress in the case of all browsers. If a browser does not fully support the HTML5 File API then the browser polls the server every few seconds with an Ajax request to determine the percentage of the file that has been uploaded. This technique of displaying progress works with any browser which supports making Ajax requests. There is one catch. Be warned that this new feature only works with the .NET 4.0 and .NET 4.5 versions of the AjaxControlToolkit. To show upload progress, we are taking advantage of the new ASP.NET HttpRequest.GetBufferedInputStream() and HttpRequest.GetBufferlessInputStream() methods which are not supported by .NET 3.5. For example, here is what the Network tab looks like when you use the AjaxFileUpload with Microsoft Internet Explorer: Here’s what the requests in the Network tab look like: GET /WebForm1.aspx?contextKey={DA8BEDC8-B952-4d5d-8CC2-59FE922E2923}&poll=1&guid=9206FF94-76F9-B197-D1BC-EA9AD282806B HTTP/1.1 Notice that each request includes a poll=1 parameter. This parameter indicates that this is a polling request to get the size of the file buffered on the server. Here’s what the response body of a request looks like when about 20% of a file has been uploaded: Buffering to a Temporary File When you upload a file using the AjaxFileUpload control, the file upload is buffered to a temporary file located at Path.GetTempPath(). When you call the SaveAs() method, as we did in the sample page above, the temporary file is copied to a new file and then the temporary file is deleted. If you don’t call the SaveAs() method, then you must ensure that the temporary file gets deleted yourself. For example, if you want to save the file to a database then you will never call the SaveAs() method and you are responsible for deleting the file. The easiest way to delete the temporary file is to call the AjaxFileUploadEventArgs.DeleteTemporaryData() method in the UploadComplete handler: protected void AjaxFileUpload1_UploadComplete(object sender, AjaxControlToolkit.AjaxFileUploadEventArgs e) { // Save uploaded file to a database table e.DeleteTemporaryData(); } You also can call the static AjaxFileUpload.CleanAllTemporaryData() method to delete all temporary data and not only the temporary data related to the current file upload. For example, you might want to call this method on application start to ensure that all temporary data is removed whenever your application restarts. A Better MaskedEdit Extender This release of the Ajax Control Toolkit contains bug fixes for the top-voted issues related to the MaskedEdit control. We closed over 25 MaskedEdit issues. Here is a complete list of the issues addressed with this release: · 17302 MaskedEditExtender MaskType=Date, Mask=99/99/99 Undefined JS Error · 11758 MaskedEdit causes error in JScript when working with 2-digits year · 18810 Maskededitextender/validator Date validation issue · 23236 MaskEditValidator does not work with date input using format dd/mm/yyyy · 23042 Webkit based browsers (Safari, Chrome) and MaskedEditExtender · 26685 MaskedEditExtender@(ClearMaskOnLostFocus=false) adds a zero character when you each focused to target textbox · 16109 MaskedEditExtender: Negative amount, followed by decimal, sets value to positive · 11522 MaskEditExtender of AjaxtoolKit-1.0.10618.0 does not work properly for Hungarian Culture · 25988 MaskedEditExtender – CultureName (HU-hu) > DateSeparator · 23221 MaskedEditExtender date separator problem · 15233 Day and month swap in Dynamic user control · 15492 MaskedEditExtender with ClearMaskOnLostFocus and with MaskedEditValidator with ClientValidationFunction · 9389 MaskedEditValidator – when on no entry · 11392 MaskedEdit Number format messed up · 11819 MaskedEditExtender erases all values beyond first comma separtor · 13423 MaskedEdit(Extender/Validator) combo problem · 16111 MaskedEditValidator cannot validate date with DayMonthYear in UserDateFormat of MaskedEditExtender · 10901 MaskedEdit: The months and date fields swap values when you hit submit if UserDateFormat is set. · 15190 MaskedEditValidator can’t make use of MaskedEditExtender’s UserDateFormat property · 13898 MaskedEdit Extender with custom date type mask gives javascript error · 14692 MaskedEdit error in “yy/MM/dd” format. · 16186 MaskedEditExtender does not handle century properly in a date mask · 26456 MaskedEditBehavior. ConvFmtTime : function(input,loadFirst) fails if this._CultureAMPMPlaceholder == “” · 21474 Error on MaskedEditExtender working with number format · 23023 MaskedEditExtender’s ClearMaskOnLostFocus property causes problems for MaskedEditValidator when set to false · 13656 MaskedEditValidator Min/Max Date value issue Conclusion This latest release of the Ajax Control Toolkit required many hours of work by a team of talented developers. I want to thank the members of the Superexpert team for the long hours which they put into this release.

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  • Community Launch: Londrina

    - by anobre
    Hoje (20/03/2010) fizemos o evento Community Launch em Londrina. O dia começou às 09:00h com abertura online realizada pela Microsoft (Rodrigo Dias, Fabio Hara e Rogério Cordeiro), apresentando a Copa Microsoft de Talentos, informações sobre o Road Show <LINK> e produtos Microsoft que estarão no foco deste ano. Após a abertura, alguns influenciadores Microsoft da região apresentaram algumas palestras técnicas, mais voltadas a DEV, sobre os assuntos: As Novidades da Plataforma .NET (André Nobre) - Download Entity Framework 4 (Carlos dos Santos) Silverlight 4 (Marcio Althmann) A minha apresentação foi focada em 3 novidades que podem ser aplicadas no dia-a-dia dos participantes, algo bem pontual, envolvendo web forms, paralelismo e Dynamic Language Runtime. O destaque (IMHO) fica para o paralelismo, algo totalmente aplicável nas aplicações, que nos dá um resultado incrível. Apesar de já existir anteriormente, o fato de estar embutido na plataforma incentiva a rápida adoção da tecnologia. Apenas para formalizar, nos próximos dias vamos lançar localmente as reuniões presenciais para discussões técnicas do grupo Sharpcode. Se você tem interesse, e está na região de Londrina, participe! Abraços!

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  • Demystifying Silverlight Dependency Properties

    - by dwahlin
    I have the opportunity to teach a lot of people about Silverlight (amongst other technologies) and one of the topics that definitely confuses people initially is the concept of dependency properties. I confess that when I first heard about them my initial thought was “Why do we need a specialized type of property?” While you can certainly use standard CLR properties in Silverlight applications, Silverlight relies heavily on dependency properties for just about everything it does behind the scenes. In fact, dependency properties are an essential part of the data binding, template, style and animation functionality available in Silverlight. They simply back standard CLR properties. In this post I wanted to put together a (hopefully) simple explanation of dependency properties and why you should care about them if you’re currently working with Silverlight or looking to move to it.   What are Dependency Properties? XAML provides a great way to define layout controls, user input controls, shapes, colors and data binding expressions in a declarative manner. There’s a lot that goes on behind the scenes in order to make XAML work and an important part of that magic is the use of dependency properties. If you want to bind data to a property, style it, animate it or transform it in XAML then the property involved has to be a dependency property to work properly. If you’ve ever positioned a control in a Canvas using Canvas.Left or placed a control in a specific Grid row using Grid.Row then you’ve used an attached property which is a specialized type of dependency property. Dependency properties play a key role in XAML and the overall Silverlight framework. Any property that you bind, style, template, animate or transform must be a dependency property in Silverlight applications. You can programmatically bind values to controls and work with standard CLR properties, but if you want to use the built-in binding expressions available in XAML (one of my favorite features) or the Binding class available through code then dependency properties are a necessity. Dependency properties aren’t needed in every situation, but if you want to customize your application very much you’ll eventually end up needing them. For example, if you create a custom user control and want to expose a property that consumers can use to change the background color, you have to define it as a dependency property if you want bindings, styles and other features to be available for use. Now that the overall purpose of dependency properties has been discussed let’s take a look at how you can create them. Creating Dependency Properties When .NET first came out you had to write backing fields for each property that you defined as shown next: Brush _ScheduleBackground; public Brush ScheduleBackground { get { return _ScheduleBackground; } set { _ScheduleBackground = value; } } Although .NET 2.0 added auto-implemented properties (for example: public Brush ScheduleBackground { get; set; }) where the compiler would automatically generate the backing field used by get and set blocks, the concept is still the same as shown in the above code; a property acts as a wrapper around a field. Silverlight dependency properties replace the _ScheduleBackground field shown in the previous code and act as the backing store for a standard CLR property. The following code shows an example of defining a dependency property named ScheduleBackgroundProperty: public static readonly DependencyProperty ScheduleBackgroundProperty = DependencyProperty.Register("ScheduleBackground", typeof(Brush), typeof(Scheduler), null);   Looking through the code the first thing that may stand out is that the definition for ScheduleBackgroundProperty is marked as static and readonly and that the property appears to be of type DependencyProperty. This is a standard pattern that you’ll use when working with dependency properties. You’ll also notice that the property explicitly adds the word “Property” to the name which is another standard you’ll see followed. In addition to defining the property, the code also makes a call to the static DependencyProperty.Register method and passes the name of the property to register (ScheduleBackground in this case) as a string. The type of the property, the type of the class that owns the property and a null value (more on the null value later) are also passed. In this example a class named Scheduler acts as the owner. The code handles registering the property as a dependency property with the call to Register(), but there’s a little more work that has to be done to allow a value to be assigned to and retrieved from the dependency property. The following code shows the complete code that you’ll typically use when creating a dependency property. You can find code snippets that greatly simplify the process of creating dependency properties out on the web. The MVVM Light download available from http://mvvmlight.codeplex.com comes with built-in dependency properties snippets as well. public static readonly DependencyProperty ScheduleBackgroundProperty = DependencyProperty.Register("ScheduleBackground", typeof(Brush), typeof(Scheduler), null); public Brush ScheduleBackground { get { return (Brush)GetValue(ScheduleBackgroundProperty); } set { SetValue(ScheduleBackgroundProperty, value); } } The standard CLR property code shown above should look familiar since it simply wraps the dependency property. However, you’ll notice that the get and set blocks call GetValue and SetValue methods respectively to perform the appropriate operation on the dependency property. GetValue and SetValue are members of the DependencyObject class which is another key component of the Silverlight framework. Silverlight controls and classes (TextBox, UserControl, CompositeTransform, DataGrid, etc.) ultimately derive from DependencyObject in their inheritance hierarchy so that they can support dependency properties. Dependency properties defined in Silverlight controls and other classes tend to follow the pattern of registering the property by calling Register() and then wrapping the dependency property in a standard CLR property (as shown above). They have a standard property that wraps a registered dependency property and allows a value to be assigned and retrieved. If you need to expose a new property on a custom control that supports data binding expressions in XAML then you’ll follow this same pattern. Dependency properties are extremely useful once you understand why they’re needed and how they’re defined. Detecting Changes and Setting Defaults When working with dependency properties there will be times when you want to assign a default value or detect when a property changes so that you can keep the user interface in-sync with the property value. Silverlight’s DependencyProperty.Register() method provides a fourth parameter that accepts a PropertyMetadata object instance. PropertyMetadata can be used to hook a callback method to a dependency property. The callback method is called when the property value changes. PropertyMetadata can also be used to assign a default value to the dependency property. By assigning a value of null for the final parameter passed to Register() you’re telling the property that you don’t care about any changes and don’t have a default value to apply. Here are the different constructor overloads available on the PropertyMetadata class: PropertyMetadata Constructor Overload Description PropertyMetadata(Object) Used to assign a default value to a dependency property. PropertyMetadata(PropertyChangedCallback) Used to assign a property changed callback method. PropertyMetadata(Object, PropertyChangedCalback) Used to assign a default property value and a property changed callback.   There are many situations where you need to know when a dependency property changes or where you want to apply a default. Performing either task is easily accomplished by creating a new instance of the PropertyMetadata class and passing the appropriate values to its constructor. The following code shows an enhanced version of the initial dependency property code shown earlier that demonstrates these concepts: public Brush ScheduleBackground { get { return (Brush)GetValue(ScheduleBackgroundProperty); } set { SetValue(ScheduleBackgroundProperty, value); } } public static readonly DependencyProperty ScheduleBackgroundProperty = DependencyProperty.Register("ScheduleBackground", typeof(Brush), typeof(Scheduler), new PropertyMetadata(new SolidColorBrush(Colors.LightGray), ScheduleBackgroundChanged)); private static void ScheduleBackgroundChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { var scheduler = d as Scheduler; scheduler.Background = e.NewValue as Brush; } The code wires ScheduleBackgroundProperty to a property change callback method named ScheduleBackgroundChanged. What’s interesting is that this callback method is static (as is the dependency property) so it gets passed the instance of the object that owns the property that has changed (otherwise we wouldn’t be able to get to the object instance). In this example the dependency object is cast to a Scheduler object and its Background property is assigned to the new value of the dependency property. The code also handles assigning a default value of LightGray to the dependency property by creating a new instance of a SolidColorBrush. To Sum Up In this post you’ve seen the role of dependency properties and how they can be defined in code. They play a big role in XAML and the overall Silverlight framework. You can think of dependency properties as being replacements for fields that you’d normally use with standard CLR properties. In addition to a discussion on how dependency properties are created, you also saw how to use the PropertyMetadata class to define default dependency property values and hook a dependency property to a callback method. The most important thing to understand with dependency properties (especially if you’re new to Silverlight) is that they’re needed if you want a property to support data binding, animations, transformations and styles properly. Any time you create a property on a custom control or user control that has these types of requirements you’ll want to pick a dependency property over of a standard CLR property with a backing field. There’s more that can be covered with dependency properties including a related property called an attached property….more to come.

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  • Roadshow Microsoft – Primeira Parada: Londrina, PR

    - by anobre
    Hoje (23/03) tivemos aqui em Londrina a primeira parada do Roadshow Microsoft, com apresentação de diversos produtos com aplicação em cenários técnicos. Como já é de costume, o evento reuniu alguns dos melhores profissionais de DEV e INFRA, com informações extremamente úteis sobre .NET Framework 4, Entity Framework, Exchange, Sharepoint, entre outras tecnologias e produtos. Na minha visão, o evento conseguiu atender a expectativa dos participantes, através dos cenários técnicos criados para a ficticia Adventure Works (acho que eu conheço esta empresa… :). Através da participação ativa de todos, as tracks de DEV e INFRA tiveram o sucesso aparente no comentário do pessoal nos intervalos e almoço. Depois das palestras, lá por 19h, tivemos um jantar com o pessoal da Microsoft e influenciadores da região, onde, até as 21h, discutimos muita coisa (até Commerce Server!). Esta aproximação com o time de comunidades da Microsoft, além de alguns “penetras” como o próprio Alex disse, é extremamente importante e útil, visto que passamos conhecemos a fundo as intenções e futuras ações da Microsoft visando as comunidades locais. Para concluir, algo que sempre digo: participe de alguma comunidade técnica da sua região. Entre em contato com influenciadores, conheça os grupos de usuários perto de você e não perca tempo. Ter o conhecimento perto de você, contribuir e crescer profissionalmente não tem preço. Obrigado novamente a todo time, em especial a Fabio Hara, Rodrigo Dias, Alex Schulz, Alvaro Rezende, Murilo e Renato Haddad. Abraços. OBS.: Lembre-se: em Londrina e região, procure o Sharpcode! :) OBS. 2: Se você é de Londrina e não participou, não perca mais oportunidades. Alias, se o seu chefe não deixa você ir, se você tem que participar de sorteio para ter uma chance de ir, ou se a sua empresa nem fica sabendo de eventos como este, acho que tá na hora de você pensar em outros opções né? :)

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  • C# 4.0: Alternative To Optional Arguments

    - by Paulo Morgado
    Like I mentioned in my last post, exposing publicly methods with optional arguments is a bad practice (that’s why C# has resisted to having it, until now). You might argument that your method or constructor has to many variants and having ten or more overloads is a maintenance nightmare, and you’re right. But the solution has been there for ages: have an arguments class. The arguments class pattern is used in the .NET Framework is used by several classes, like XmlReader and XmlWriter that use such pattern in their Create methods, since version 2.0: XmlReaderSettings settings = new XmlReaderSettings(); settings.ValidationType = ValidationType.Auto; XmlReader.Create("file.xml", settings); With this pattern, you don’t have to maintain a long list of overloads and any default values for properties of XmlReaderSettings (or XmlWriterSettings for XmlWriter.Create) can be changed or new properties added in future implementations that won’t break existing compiled code. You might now argue that it’s too much code to write, but, with object initializers added in C# 3.0, the same code can be written like this: XmlReader.Create("file.xml", new XmlReaderSettings { ValidationType = ValidationType.Auto }); Looks almost like named and optional arguments, doesn’t it? And, who knows, in a future version of C#, it might even look like this: XmlReader.Create("file.xml", new { ValidationType = ValidationType.Auto });

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  • Putting a base in the middle

    - by PSteele
    From Eric Lippert's Blog: Here’s a crazy-seeming but honest-to-goodness real customer scenario that got reported to me recently. There are three DLLs involved, Alpha.DLL, Bravo.DLL and Charlie.DLL. The classes in each are: public class Alpha // In Alpha.DLL {   public virtual void M()   {     Console.WriteLine("Alpha");   } } public class Bravo: Alpha // In Bravo.DLL { } public class Charlie : Bravo // In Charlie.DLL {   public override void M()   {     Console.WriteLine("Charlie");     base.M();   } } Perfectly sensible. You call M on an instance of Charlie and it says “Charlie / Alpha”. Now the vendor who supplies Bravo.DLL ships a new version which has this code: public class Bravo: Alpha {   public override void M()   {     Console.WriteLine("Bravo");     base.M();   } } The question is: what happens if you call Charlie.M without recompiling Charlie.DLL, but you are loading the new version of Bravo.DLL? The customer was quite surprised that the output is still “Charlie / Alpha”, not “Charlie / Bravo / Alpha”. Read the full post for a very interesting discussion of the design of C#, the CLR, method resolution and more. Technorati Tags: .NET,C#,CLR

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  • Announcing Sesame Data Browser

    - by Fabrice Marguerie
    At the occasion of MIX10, which is currently taking place in Las Vegas, I'd like to announce Sesame Data Browser.Sesame will be a suite of tools for dealing with data, and Sesame Data Browser will be the first tool from that suite.Today, during the second MIX10 keynote, Microsoft demonstrated how they are pushing hard to get OData adopted. If you don't know about OData, you can visit the just revamped dedicated website: http://odata.org. There you'll find about the OData protocol, which allows you to publish and consume data on the web, the OData SDK (with client libraries for .NET, Java, Javascript, PHP, iPhone, and more), a list of OData producers, and a list of OData consumers.This is where Sesame Data Browser comes into play. It's one of the tools you can use today to consume OData.I'll let you have a look, but be aware that this is just a preview and many additional features are coming soon.Sesame Data Browser is part of a bigger picture than just OData that will take shape over the coming months. Sesame is a project I've been working on for many months now, so what you see now is just a start :-)I hope you'll enjoy what you see. Let me know what you think.

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  • Dotfuscator Deep Dive with WP7

    - by Bil Simser
    I thought I would share some experience with code obfuscation (specifically the Dotfuscator product) and Windows Phone 7 apps. These days twitter is a buzz with black hat and white operations coming out about how the marketplace is insecure and Microsoft failed, blah, blah, blah. So it’s that much more important to protect your intellectual property. You should protect it no matter what when releasing apps into the wild but more so when someone is paying for them. You want to protect the time and effort that went into your code and have some comfort that the casual hacker isn’t going to usurp your next best thing. Enter code obfuscation. Code obfuscation is one tool that can help protect your IP. Basically it goes into your compiled assemblies, rewrites things at an IL level (like renaming methods and classes and hiding logic flow) and rewrites it back so that the assembly or executable is still fully functional but prying eyes using a tool like ILDASM or Reflector can’t see what’s going on.  You can read more about code obfuscation here on Wikipedia. A word to the wise. Code obfuscation isn’t 100% secure. More so on the WP7 platform where the OS expects certain things to be as they were meant to be. So don’t expect 100% obfuscation of every class and every method and every property. It’s just not going to happen. What this does do is give you some level of protection but don’t put all your eggs in one basket and call it done. Like I said, this is just one step in the process. There are a few tools out there that provide code obfuscation and support the Windows Phone 7 platform (see links to other tools at the end of this post). One such tool is Dotfuscator from PreEmptive solutions. The thing about Dotfuscator is that they’ve struck a deal with Microsoft to provide a *free* copy of their commercial product for Windows Phone 7. The only drawback is that it only runs until March 31, 2010. However it’s a good place to start and the focus of this article. Getting Started When you fire up Dotfuscator you’re presented with a dialog to start a new project or load a previous one. We’ll start with a new project. You’re then looking at a somewhat blank screen that shows an Input tab (among others) and you’re probably wondering what to do? Click on the folder icon (first one) and browse to where your xap file is. At this point you can save the project and click on the arrow to start the process. Bam! You’re done. Right? Think again. The program did indeed run and create a new version of your xap (doing it’s thing and rewriting back your *obfuscated* assemblies) but let’s take a look at the assembly in Reflector to see the end result. Remember a xap file is really just a glorified zip file (or cab file if you prefer). When you ran Dotfuscator for the first time with the default settings you’ll see it created a new version of your xap in a folder under “My Documents” called “Dotfuscated” (you can configure the output directory in settings). Here’s the new xap file. Since a xap is just a zip, rename it to .cab or .zip or something and open it with your favorite unarchive program (I use WinRar but it doesn’t matter as long as it can unzip files). If you already have the xap file associated with your unarchive tool the rename isn’t needed. Once renamed extract the contents of the xap to your hard drive: Now you’ll have a folder with the contents of the xap file extracted: Double click or load up your assembly (WindowsPhoneDataBoundApplication1.dll in the example) in Reflector and let’s see the results: Hmm. That doesn’t look right. I can see all the methods and the code is all there for my LoadData method I wanted to protect. Product failure. Let’s return it for a refund. Hold your horses. We need to check out the settings in the program first. Remember when we loaded up our xap file. It started us on the Input tab but there was a settings tab before that. Wonder what it does? Here’s the default settings: Renaming Taking a closer look, all of the settings in Feature are disabled. WTF? Yeah, it leaves me scratching my head why an obfuscator by default doesn’t obfuscate. However it’s a simple fix to change these settings. Let’s enable Renaming as it sounds like a good start. Renaming obscures code by renaming methods and fields to names that are not understandable. Great. Run the tool again and go through the process of unzipping the updated xap and let’s take a look in Reflector again at our project. This looks a lot better. Lots of methods named a, b, c, d, etc. That’ll help slow hackers down a bit. What about our logic that we spent days weeks on? Let’s take a look at the LoadData method: What gives? We have renaming enabled but all of our code is still there. If you look through all your methods you’ll find it’s still sitting there out in the open. Control Flow Back to the settings page again. Let’s enable Control Flow now. Control Flow obfuscation synthesizes branching, conditional, and iterative constructs (such as if, for, and while) that produce valid executable logic, but yield non-deterministic semantic results when decompilation is attempted. In other words, the code runs as before, but decompilers cannot reproduce the original code. Do the dance again and let’s see the results in Reflector. Ahh, that’s better. Methods renamed *and* nobody can look at our LoadData method now. Life is good. More than Minimum This is the bare minimum to obfuscate your xap to at least a somewhat comfortable level. However I did find that while this worked in my Hello World demo, it didn’t work on one of my real world apps. I had to do some extra tweaking with that. Below are the screens that I used on one app that worked. I’m not sure what it was about the app that the approach above didn’t work with (maybe the extra assembly?) but it works and I’m happy with it. YMMV. Remember to test your obfuscated app on your device first before submitting to ensure you haven’t obfuscated the obfuscator. settings tab: rename tab: string encryption tab: premark tab: A few final notes Play with the settings and keep bumping up the bar to try to get as much obfuscation as you can. The more the better but remember you can overdo it. Always (always, always, always) deploy your obfuscated xap to your device and test it before submitting to the marketplace. I didn’t and got rejected because I had gone overboard with the obfuscation so the app wouldn’t launch at all. Not everything is going to be obfuscated. Specifically I don’t see a way to obfuscate auto properties and a few other language features. Again, if you crank the settings up you might hide these but I haven’t spent a lot of time optimizing the process. Some people might say to obfuscate your xaml using string encryption but again, test, test, test. Xaml is picky so too much obfuscation (or any) might disable your app or produce odd rendering effets. Remember, obfuscation is not 100% secure! Don’t rely on it as a sole way of protecting your assets. Other Tools Dotfuscator is one just product and isn’t the end-all be-all to obfuscation so check out others below. For example, Crypto can make it so Reflector doesn’t even recognize the app as a .NET one and won’t open it. Others can encrypt resources and Xaml markup files. Here are some other obfuscators that support the Windows Phone 7 platform. Feel free to give them a try and let people know your experience with them! Dotfuscator Windows Phone Edition Crypto Obfuscator for .NET DeepSea Obfuscation

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  • TFS 2010–Bridging the gap between developers and testers

    - by guybarrette
    Last fall, the Montreal .NET Community presented a full day on ALM with a session called “Bridging the gap between developers and testers”. It was a huge success. TFS experts Etienne Tremblay and Vincent Grondin presented again this session at the Ottawa user group in January and this time, the event was recorded by DevTeach in collaboration with Microsoft.  This 7 hours training is broken in 13 videos that you can watch online for free on the DevTeach Website.  If you’re interested in TFS, how to migrate from VSS, the TFS testing tools, how to set the TFS testing lab, how to test a UI and how to automate the tests, this is a must see series.   Here’s the segments list: Intro Migrating from VSS to TFS Automating the build Where’s our backlog? Adding a tester to the team Tester at work Bridging the gap Stop, we have a problem! Let’s get back on track Multi-environment testing Testing in the lab UI Automation Validating UI automation Look boss, no hands! http://www.devteach.com/ALM-TFS2010-Bridgingthegap.aspx var addthis_pub="guybarrette";

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  • When SharePoint Designer has its own designs

    - by PeterBrunone
    Recently, a colleague came to me with a simple task and an inscrutable error.  He just wanted to populate a text field with a querystring value.  If you've ever done this in SPD, you know it's fairly simple:  create a parameter, map it to a querystring value, and then use the resulting parameter name in your form field. Having done so, however, he was told the following by the ASP.NET "yellow barf page": The 'Text' property of 'asp:TextBox' does not allow child objects. As it turns out, he had done everything correctly.  The problem was that SharePoint Designer had decided the best place for his FieldDescription control was INSIDE the TextBox control.  Obviously the compiler doesn't know what to do with that.  When the FieldDescription was moved to a less obtrusive location, everything worked as expected.The moral of the story is, as always, don't trust what any WYSIWYG tool gives you.  If it looks great, then fine.  However, if there's a problem, remember that Design mode was written by human beings who make mistakes... just like the rest of us.Take THAT, Skynet.

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  • Understanding C# async / await (2) Awaitable / Awaiter Pattern

    - by Dixin
    What is awaitable Part 1 shows that any Task is awaitable. Actually there are other awaitable types. Here is an example: Task<int> task = new Task<int>(() => 0); int result = await task.ConfigureAwait(false); // Returns a ConfiguredTaskAwaitable<TResult>. The returned ConfiguredTaskAwaitable<TResult> struct is awaitable. And it is not Task at all: public struct ConfiguredTaskAwaitable<TResult> { private readonly ConfiguredTaskAwaiter m_configuredTaskAwaiter; internal ConfiguredTaskAwaitable(Task<TResult> task, bool continueOnCapturedContext) { this.m_configuredTaskAwaiter = new ConfiguredTaskAwaiter(task, continueOnCapturedContext); } public ConfiguredTaskAwaiter GetAwaiter() { return this.m_configuredTaskAwaiter; } } It has one GetAwaiter() method. Actually in part 1 we have seen that Task has GetAwaiter() method too: public class Task { public TaskAwaiter GetAwaiter() { return new TaskAwaiter(this); } } public class Task<TResult> : Task { public new TaskAwaiter<TResult> GetAwaiter() { return new TaskAwaiter<TResult>(this); } } Task.Yield() is a another example: await Task.Yield(); // Returns a YieldAwaitable. The returned YieldAwaitable is not Task either: public struct YieldAwaitable { public YieldAwaiter GetAwaiter() { return default(YieldAwaiter); } } Again, it just has one GetAwaiter() method. In this article, we will look at what is awaitable. The awaitable / awaiter pattern By observing different awaitable / awaiter types, we can tell that an object is awaitable if It has a GetAwaiter() method (instance method or extension method); Its GetAwaiter() method returns an awaiter. An object is an awaiter if: It implements INotifyCompletion or ICriticalNotifyCompletion interface; It has an IsCompleted, which has a getter and returns a Boolean; it has a GetResult() method, which returns void, or a result. This awaitable / awaiter pattern is very similar to the iteratable / iterator pattern. Here is the interface definitions of iteratable / iterator: public interface IEnumerable { IEnumerator GetEnumerator(); } public interface IEnumerator { object Current { get; } bool MoveNext(); void Reset(); } public interface IEnumerable<out T> : IEnumerable { IEnumerator<T> GetEnumerator(); } public interface IEnumerator<out T> : IDisposable, IEnumerator { T Current { get; } } In case you are not familiar with the out keyword, please find out the explanation in Understanding C# Covariance And Contravariance (2) Interfaces. The “missing” IAwaitable / IAwaiter interfaces Similar to IEnumerable and IEnumerator interfaces, awaitable / awaiter can be visualized by IAwaitable / IAwaiter interfaces too. This is the non-generic version: public interface IAwaitable { IAwaiter GetAwaiter(); } public interface IAwaiter : INotifyCompletion // or ICriticalNotifyCompletion { // INotifyCompletion has one method: void OnCompleted(Action continuation); // ICriticalNotifyCompletion implements INotifyCompletion, // also has this method: void UnsafeOnCompleted(Action continuation); bool IsCompleted { get; } void GetResult(); } Please notice GetResult() returns void here. Task.GetAwaiter() / TaskAwaiter.GetResult() is of such case. And this is the generic version: public interface IAwaitable<out TResult> { IAwaiter<TResult> GetAwaiter(); } public interface IAwaiter<out TResult> : INotifyCompletion // or ICriticalNotifyCompletion { bool IsCompleted { get; } TResult GetResult(); } Here the only difference is, GetResult() return a result. Task<TResult>.GetAwaiter() / TaskAwaiter<TResult>.GetResult() is of this case. Please notice .NET does not define these IAwaitable / IAwaiter interfaces at all. As an UI designer, I guess the reason is, IAwaitable interface will constraint GetAwaiter() to be instance method. Actually C# supports both GetAwaiter() instance method and GetAwaiter() extension method. Here I use these interfaces only for better visualizing what is awaitable / awaiter. Now, if looking at above ConfiguredTaskAwaitable / ConfiguredTaskAwaiter, YieldAwaitable / YieldAwaiter, Task / TaskAwaiter pairs again, they all “implicitly” implement these “missing” IAwaitable / IAwaiter interfaces. In the next part, we will see how to implement awaitable / awaiter. Await any function / action In C# await cannot be used with lambda. This code: int result = await (() => 0); will cause a compiler error: Cannot await 'lambda expression' This is easy to understand because this lambda expression (() => 0) may be a function or a expression tree. Obviously we mean function here, and we can tell compiler in this way: int result = await new Func<int>(() => 0); It causes an different error: Cannot await 'System.Func<int>' OK, now the compiler is complaining the type instead of syntax. With the understanding of the awaitable / awaiter pattern, Func<TResult> type can be easily made into awaitable. GetAwaiter() instance method, using IAwaitable / IAwaiter interfaces First, similar to above ConfiguredTaskAwaitable<TResult>, a FuncAwaitable<TResult> can be implemented to wrap Func<TResult>: internal struct FuncAwaitable<TResult> : IAwaitable<TResult> { private readonly Func<TResult> function; public FuncAwaitable(Func<TResult> function) { this.function = function; } public IAwaiter<TResult> GetAwaiter() { return new FuncAwaiter<TResult>(this.function); } } FuncAwaitable<TResult> wrapper is used to implement IAwaitable<TResult>, so it has one instance method, GetAwaiter(), which returns a IAwaiter<TResult>, which wraps that Func<TResult> too. FuncAwaiter<TResult> is used to implement IAwaiter<TResult>: public struct FuncAwaiter<TResult> : IAwaiter<TResult> { private readonly Task<TResult> task; public FuncAwaiter(Func<TResult> function) { this.task = new Task<TResult>(function); this.task.Start(); } bool IAwaiter<TResult>.IsCompleted { get { return this.task.IsCompleted; } } TResult IAwaiter<TResult>.GetResult() { return this.task.Result; } void INotifyCompletion.OnCompleted(Action continuation) { new Task(continuation).Start(); } } Now a function can be awaited in this way: int result = await new FuncAwaitable<int>(() => 0); GetAwaiter() extension method As IAwaitable shows, all that an awaitable needs is just a GetAwaiter() method. In above code, FuncAwaitable<TResult> is created as a wrapper of Func<TResult> and implements IAwaitable<TResult>, so that there is a  GetAwaiter() instance method. If a GetAwaiter() extension method  can be defined for Func<TResult>, then FuncAwaitable<TResult> is no longer needed: public static class FuncExtensions { public static IAwaiter<TResult> GetAwaiter<TResult>(this Func<TResult> function) { return new FuncAwaiter<TResult>(function); } } So a Func<TResult> function can be directly awaited: int result = await new Func<int>(() => 0); Using the existing awaitable / awaiter - Task / TaskAwaiter Remember the most frequently used awaitable / awaiter - Task / TaskAwaiter. With Task / TaskAwaiter, FuncAwaitable / FuncAwaiter are no longer needed: public static class FuncExtensions { public static TaskAwaiter<TResult> GetAwaiter<TResult>(this Func<TResult> function) { Task<TResult> task = new Task<TResult>(function); task.Start(); return task.GetAwaiter(); // Returns a TaskAwaiter<TResult>. } } Similarly, with this extension method: public static class ActionExtensions { public static TaskAwaiter GetAwaiter(this Action action) { Task task = new Task(action); task.Start(); return task.GetAwaiter(); // Returns a TaskAwaiter. } } an action can be awaited as well: await new Action(() => { }); Now any function / action can be awaited: await new Action(() => HelperMethods.IO()); // or: await new Action(HelperMethods.IO); If function / action has parameter(s), closure can be used: int arg0 = 0; int arg1 = 1; int result = await new Action(() => HelperMethods.IO(arg0, arg1)); Using Task.Run() The above code is used to demonstrate how awaitable / awaiter can be implemented. Because it is a common scenario to await a function / action, so .NET provides a built-in API: Task.Run(): public class Task2 { public static Task Run(Action action) { // The implementation is similar to: Task task = new Task(action); task.Start(); return task; } public static Task<TResult> Run<TResult>(Func<TResult> function) { // The implementation is similar to: Task<TResult> task = new Task<TResult>(function); task.Start(); return task; } } In reality, this is how we await a function: int result = await Task.Run(() => HelperMethods.IO(arg0, arg1)); and await a action: await Task.Run(() => HelperMethods.IO());

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  • C# 4.0: Covariance And Contravariance In Generics Made Easy

    - by Paulo Morgado
    In my last post, I went through what is variance in .NET 4.0 and C# 4.0 in a rather theoretical way. Now, I’m going to try to make it a bit more down to earth. Given: class Base { } class Derived : Base { } Such that: Trace.Assert(typeof(Base).IsClass && typeof(Derived).IsClass && typeof(Base).IsGreaterOrEqualTo(typeof(Derived))); Covariance interface ICovariantIn<out T> { } Trace.Assert(typeof(ICovariantIn<Base>).IsGreaterOrEqualTo(typeof(ICovariantIn<Derived>))); Contravariance interface ICovariantIn<out T> { } Trace.Assert(typeof(IContravariantIn<Derived>).IsGreaterOrEqualTo(typeof(IContravariantIn<Base>))); Invariance interface IInvariantIn<T> { } Trace.Assert(!typeof(IInvariantIn<Base>).IsGreaterOrEqualTo(typeof(IInvariantIn<Derived>)) && !typeof(IInvariantIn<Derived>).IsGreaterOrEqualTo(typeof(IInvariantIn<Base>))); Where: public static class TypeExtensions { public static bool IsGreaterOrEqualTo(this Type self, Type other) { return self.IsAssignableFrom(other); } }

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  • 36 Hour Free Offer: jQuery Fundamentals Training

    - by ScottGu
    Pluralsight (a great .NET training company) is offering the opportunity to watch their jQuery Fundamentals course for free for the next 36 hours. The course is presented by the most excellent Dan Wahlin and contains 5 hours of great end to end content.  Pluralsight will be offering this jQuery Fundamentals course for free until Thursday evening (9pm PST). Pluralsight has about 100 other great training courses available similar to this one.  They recently launched a new subscription plan that allows you to watch all of their courses online starting from $29 a month.  They also offer a 10 day free trial option that you can use to try it out.  You can learn more about it here. Free jQuery 1.5 Visual Cheat Sheet While on the topic of jQuery, I wanted to link to one other useful resource to download if you are using jQuery – which is a free jQuery PDF “cheat sheet” for the jQuery 1.5 APIs. You can download it for free here. Hope this helps, Scott P.S. I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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  • Call for Abstracts for the Fall Silverlight Connections Conference

    - by dwahlin
    We are putting out a call for abstracts to present at the Fall 2010 Silverlight Connections conference in Las Vegas, Nov 1-4, 2010. The due date for submissions is April 26, 2010. For submitting sessions, please use this URL: http://www.deeptraining.com/devconnections/abstracts Please keep the abstracts under 200 words each and in one paragraph. No bulleted items and line breaks, and please use a spell-checker. Do not email abstracts, you need to use the web-based tool to submit them. Please submit at least 3 abstracts. It will help your chances of being selected if you submitted 5 or more abstracts. Also, you are encouraged to suggest all-day pre or post conference workshops as well. We need to finalize the conference content and the tracks in just a few short weeks so we need your abstracts by April 26th. No exceptions will be granted on late submissions! Topics of interest include (but are not limited to): Silverlight Data and XML Technologies Customizing Silverlight Applications with Styles and Templates Using Expression Blend 4 Windows Phone 7 Application Development Silverlight Architecture, Patterns and Practices Securing Silverlight Applications Using WCF RIA Services Writing Elevated Trust Applications Anything else related to Silverlight You can use the URL above to submit sessions to Microsoft ASP.NET Connections, Silverlight Connections, Visual Studio Connections, or SQL Server Connections. Please realize that while we want a lot of the new and the cool, it's also okay to propose sessions on the more mundane "real world" stuff as it pertains to Silverlight. What you will get if selected: $500 per regular conference talk. Compensation for full-day workshops ranges from $500 for 1-20 attendees to $2500 for 200+ attendees. Coach airfare and hotel stay paid by the conference. Free admission to all of the co-located conferences Speaker party The adoration of attendees Your continued support of Microsoft Silverlight Connections and the other DevConnections conferences is appreciated. Good luck and thank you. Dan Wahlin and Paul Litwin Silverlight Conference Chairs

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  • Visual Studio Talk Show #114 is now online - Le responsable de projet est-il mort? (French)

    - by guybarrette
    http://www.visualstudiotalkshow.com Bernard Fedotoff: Le responsable de projet est-il mort? Nous discutons avec Bernard Fedotoff sur comment jumeler la gestion de projet et les méthodes de développement agile. Entre autres, avec les méthodes agiles on se demande où est la place du responsable de projet. Bernard Fedotoff est Microsoft Regional Director depuis 1996 ; il a animé les Devdays et Techdays en Suisse et en France depuis 1997. Il a été fondateur et PDG de PSEngineering depuis 1990, société qu’il a revendue en 2004. En 2005, il a fondé la société Agilcom. Bernard a mené auprès de clients français, suisses, et d'afrique du nord de nombreuses missions en technologie .Net, d'architecture et de coaching d'équipes de dévoppement. Son passé de Pdg et son expertise technologique apportent aux projets qu'il accompagne deux points de vue riches d'expériences et de convictions. Il a aussi accompagné la mise en place de plateaux offshores vers la Tunisie, en implémentant des approches Agile avec Team Foundation Server. Enfin, il est aussi co-auteur de nombreux ateliers des coachs publiés sur le site MSDN de Microsoft France. Bernard est titulaire d’un diplôme d’ingénieur ainsi que d’un troisième cycle universitaire en robotique. Il consacre ses quelques minutes de temps libre à la montagne Télécharger l'émission Si vous désirez un accès direct au fichier audio en format MP3, nous vous invitons à télécharger le fichier en utilisant un des boutons ci-dessous. Si vous désirez utiliser le feed RSS pour télécharger l'émission, nous vous invitons à vous abonnez en utilisant le bouton ci-dessous. Si vous désirez utiliser le répertoire iTunes Podcast pour télécharger l'émission, nous vous encourageons à vous abonnez en utilisant le bouton ci-dessous. var addthis_pub="guybarrette";

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  • My Code Kata–A Solution Kata

    - by Glav
    There are many developers and coders out there who like to do code Kata’s to keep their coding ability up to scratch and to practice their skills. I think it is a good idea. While I like the concept, I find them dead boring and of minimal purpose. Yes, they serve to hone your skills but that’s about it. They are often quite abstract, in that they usually focus on a small problem set requiring specific solutions. It is fair enough as that is how they are designed but again, I find them quite boring. What I personally like to do is go for something a little larger and a little more fun. It takes a little more time and is not as easily executed as a kata though, but it services the same purposes from a practice perspective and allows me to continue to solve some problems that are not directly part of the initial goal. This means I can cover a broader learning range and have a bit more fun. If I am lucky, sometimes they even end up being useful tools. With that in mind, I thought I’d share my current ‘kata’. It is not really a code kata as it is too big. I prefer to think of it as a ‘solution kata’. The code is on bitbucket here. What I wanted to do was create a kind of simplistic virtual world where I can create a player, or a class, stuff it into the world, and see if it survives, and can navigate its way to the exit. Requirements were pretty simple: Must be able to define a map to describe the world using simple X,Y co-ordinates. Z co-ordinates as well if you feel like getting clever. Should have the concept of entrances, exists, solid blocks, and potentially other materials (again if you want to get clever). A coder should be able to easily write a class which will act as an inhabitant of the world. An inhabitant will receive stimulus from the world in the form of surrounding environment and be able to make a decision on action which it passes back to the ‘world’ for processing. At a minimum, an inhabitant will have sight and speed characteristics which determine how far they can ‘see’ in the world, and how fast they can move. Coders who write a really bad ‘inhabitant’ should not adversely affect the rest of world. Should allow multiple inhabitants in the world. So that was the solution I set out to act as a practice solution and a little bit of fun. It had some interesting problems to solve and I figured, if it turned out ok, I could potentially use this as a ‘developer test’ for interviews. Ask a potential coder to write a class for an inhabitant. Show the coder the map they will navigate, but also mention that we will use their code to navigate a map they have not yet seen and a little more complex. I have been playing with solution for a short time now and have it working in basic concepts. Below is a screen shot using a very basic console visualiser that shows the map, boundaries, blocks, entrance, exit and players/inhabitants. The yellow asterisks ‘*’ are the players, green ‘O’ the entrance, purple ‘^’ the exit, maroon/browny ‘#’ are solid blocks. The players can move around at different speeds, knock into each others, and make directional movement decisions based on what they see and who is around them. It has been quite fun to write and it is also quite fun to develop different players to inject into the world. The code below shows a really simple implementation of an inhabitant that can work out what to do based on stimulus from the world. It is pretty simple and just tries to move in some direction if there is nothing blocking the path. public class TestPlayer:LivingEntity { public TestPlayer() { Name = "Beta Boy"; LifeKey = Guid.NewGuid(); } public override ActionResult DecideActionToPerform(EcoDev.Core.Common.Actions.ActionContext actionContext) { try { var action = new MovementAction(); // move forward if we can if (actionContext.Position.ForwardFacingPositions.Length > 0) { if (CheckAccessibilityOfMapBlock(actionContext.Position.ForwardFacingPositions[0])) { action.DirectionToMove = MovementDirection.Forward; return action; } } if (actionContext.Position.LeftFacingPositions.Length > 0) { if (CheckAccessibilityOfMapBlock(actionContext.Position.LeftFacingPositions[0])) { action.DirectionToMove = MovementDirection.Left; return action; } } if (actionContext.Position.RearFacingPositions.Length > 0) { if (CheckAccessibilityOfMapBlock(actionContext.Position.RearFacingPositions[0])) { action.DirectionToMove = MovementDirection.Back; return action; } } if (actionContext.Position.RightFacingPositions.Length > 0) { if (CheckAccessibilityOfMapBlock(actionContext.Position.RightFacingPositions[0])) { action.DirectionToMove = MovementDirection.Right; return action; } } return action; } catch (Exception ex) { World.WriteDebugInformation("Player: "+ Name, string.Format("Player Generated exception: {0}",ex.Message)); throw ex; } } private bool CheckAccessibilityOfMapBlock(MapBlock block) { if (block == null || block.Accessibility == MapBlockAccessibility.AllowEntry || block.Accessibility == MapBlockAccessibility.AllowExit || block.Accessibility == MapBlockAccessibility.AllowPotentialEntry) { return true; } return false; } } It is simple and it seems to work well. The world implementation itself decides the stimulus context that is passed to he inhabitant to make an action decision. All movement is carried out on separate threads and timed appropriately to be as fair as possible and to cater for additional skills such as speed, and eventually maybe stamina, strength, with actions like fighting. It is pretty fun to make up random maps and see how your inhabitant does. You can download the code from here. Along the way I have played with parallel extensions to make the compute intensive stuff spread across all cores, had to heavily factor in visibility of methods and properties so design of classes was paramount, work out movement algorithms that play fairly in the world and properly favour the players with higher abilities, as well as a host of other issues. So that is my ‘solution kata’. If I keep going with it, I may develop a web interface for it where people can upload assemblies and watch their player within a web browser visualiser and maybe even a map designer. What do you do to keep the fires burning?

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  • Visual Studio Talk Show #114 is now online - Le responsable de projet est-il mort? (French)

    - by guybarrette
    http://www.visualstudiotalkshow.com Bernard Fedotoff: Le responsable de projet est-il mort? Nous discutons avec Bernard Fedotoff sur comment jumeler la gestion de projet et les méthodes de développement agile. Entre autres, avec les méthodes agiles on se demande où est la place du responsable de projet. Bernard Fedotoff est Microsoft Regional Director depuis 1996 ; il a animé les Devdays et Techdays en Suisse et en France depuis 1997. Il a été fondateur et PDG de PSEngineering depuis 1990, société qu’il a revendue en 2004. En 2005, il a fondé la société Agilcom. Bernard a mené auprès de clients français, suisses, et d'afrique du nord de nombreuses missions en technologie .Net, d'architecture et de coaching d'équipes de dévoppement. Son passé de Pdg et son expertise technologique apportent aux projets qu'il accompagne deux points de vue riches d'expériences et de convictions. Il a aussi accompagné la mise en place de plateaux offshores vers la Tunisie, en implémentant des approches Agile avec Team Foundation Server. Enfin, il est aussi co-auteur de nombreux ateliers des coachs publiés sur le site MSDN de Microsoft France. Bernard est titulaire d’un diplôme d’ingénieur ainsi que d’un troisième cycle universitaire en robotique. Il consacre ses quelques minutes de temps libre à la montagne Télécharger l'émission Si vous désirez un accès direct au fichier audio en format MP3, nous vous invitons à télécharger le fichier en utilisant un des boutons ci-dessous. Si vous désirez utiliser le feed RSS pour télécharger l'émission, nous vous invitons à vous abonnez en utilisant le bouton ci-dessous. Si vous désirez utiliser le répertoire iTunes Podcast pour télécharger l'émission, nous vous encourageons à vous abonnez en utilisant le bouton ci-dessous. var addthis_pub="guybarrette";

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  • Hex Dump using LINQ (in 7 lines of code)

    - by Fabrice Marguerie
    Eric White has posted an interesting LINQ query on his blog that shows how to create a Hex Dump in something like 7 lines of code.Of course, this is not production grade code, but it's another good example that demonstrates the expressiveness of LINQ.Here is the code:byte[] ba = File.ReadAllBytes("test.xml");int bytesPerLine = 16;string hexDump = ba.Select((c, i) => new { Char = c, Chunk = i / bytesPerLine })    .GroupBy(c => c.Chunk)    .Select(g => g.Select(c => String.Format("{0:X2} ", c.Char))        .Aggregate((s, i) => s + i))    .Select((s, i) => String.Format("{0:d6}: {1}", i * bytesPerLine, s))    .Aggregate("", (s, i) => s + i + Environment.NewLine);Console.WriteLine(hexDump); Here is a sample output:000000: FF FE 3C 00 3F 00 78 00 6D 00 6C 00 20 00 76 00000016: 65 00 72 00 73 00 69 00 6F 00 6E 00 3D 00 22 00000032: 31 00 2E 00 30 00 22 00 20 00 65 00 6E 00 63 00000048: 6F 00 64 00 69 00 6E 00 67 00 3D 00 22 00 75 00000064: 3E 00Eric White reports that he typically notices that declarative code is only 20% as long as imperative code. Cross-posted from http://linqinaction.net

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  • ZenGallery: a minimalist image gallery for Orchard

    - by Bertrand Le Roy
    There are quite a few image gallery modules for Orchard but they were not invented here I wanted something a lot less sophisticated that would be as barebones and minimalist as possible out of the box, to make customization extremely easy. So I made this, in less than two days (during which I got distracted a lot). Nwazet.ZenGallery uses existing Orchard features as much as it can: Galleries are just a content part that can be added to any type The set of photos in a gallery is simply defined by a folder in Media Managing the images in a gallery is done using the standard media management from Orchard Ordering of photos is simply alphabetical order of the filenames (use 1_, 2_, etc. prefixes if you have to) The path to the gallery folder is mapped from the content item using a token-based pattern The pattern can be set per content type You can edit the generated gallery path for each item The default template is just a list of links over images, that get open in a new tab No lightbox script comes with the module, just customize the template to use your favorite script. Light, light, light. Rather than explaining in more details this very simple module, here is a video that shows how I used the module to add photo galleries to a product catalog: Adding a gallery to a product catalog You can find the module on the Orchard Gallery: https://gallery.orchardproject.net/List/Modules/Orchard.Module.Nwazet.ZenGallery/ The source code is available from BitBucket: https://bitbucket.org/bleroy/nwazet.zengallery

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  • Tweaking log4net Settings Programmatically

    - by PSteele
    A few months ago, I had to dynamically add a log4net appender at runtime.  Now I find myself in another log4net situation.  I need to modify the configuration of my appenders at runtime. My client requires all files generated by our applications to be saved to a specific location.  This location is determined at runtime.  Therefore, I want my FileAppenders to log their data to this specific location – but I won't know the location until runtime so I can't add it to the XML configuration file I'm using. No problem.  Bing is my new friend and returned a couple of hits.  I made a few tweaks to their LINQ queries and created a generic extension method for ILoggerRepository (just a hunch that I might want this functionality somewhere else in the future – sorry YAGNI fans): public static void ModifyAppenders<T>(this ILoggerRepository repository, Action<T> modify) where T:log4net.Appender.AppenderSkeleton { var appenders = from appender in log4net.LogManager.GetRepository().GetAppenders() where appender is T select appender as T;   foreach (var appender in appenders) { modify(appender); appender.ActivateOptions(); } } Now I can easily add the proper directory prefix to all of my FileAppenders at runtime: log4net.LogManager.GetRepository().ModifyAppenders<FileAppender>(a => { a.File = Path.Combine(settings.ConfigDirectory, Path.GetFileName(a.File)); }); Thanks beefycode and Wil Peck. Technorati Tags: .NET,log4net,LINQ

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  • .NET Code Evolution

    - by Alois Kraus
    Originally posted on: http://geekswithblogs.net/akraus1/archive/2013/07/24/153504.aspxAt my day job I do look at a lot of code written by other people. Most of the code is quite good and some is even a masterpiece. And there is also code which makes you think WTF… oh it was written by me. Hm not so bad after all. There are many excuses reasons for bad code. Most often it is time pressure followed by not enough ambition (who cares) or insufficient training. Normally I do care about code quality quite a lot which makes me a (perceived) slow worker who does write many tests and refines the code quite a lot because of the design deficiencies. Most of the deficiencies I do find by putting my design under stress while checking for invariants. It does also help a lot to step into the code with a debugger (sometimes also Windbg). I do this much more often when my tests are red. That way I do get a much better understanding what my code really does and not what I think it should be doing. This time I do want to show you how code can evolve over the years with different .NET Framework versions. Once there was  time where .NET 1.1 was new and many C++ programmers did switch over to get rid of not initialized pointers and memory leaks. There were also nice new data structures available such as the Hashtable which is fast lookup table with O(1) time complexity. All was good and much code was written since then. At 2005 a new version of the .NET Framework did arrive which did bring many new things like generics and new data structures. The “old” fashioned way of Hashtable were coming to an end and everyone used the new Dictionary<xx,xx> type instead which was type safe and faster because the object to type conversion (aka boxing) was no longer necessary. I think 95% of all Hashtables and dictionaries use string as key. Often it is convenient to ignore casing to make it easy to look up values which the user did enter. An often followed route is to convert the string to upper case before putting it into the Hashtable. Hashtable Table = new Hashtable(); void Add(string key, string value) { Table.Add(key.ToUpper(), value); } This is valid and working code but it has problems. First we can pass to the Hashtable a custom IEqualityComparer to do the string matching case insensitive. Second we can switch over to the now also old Dictionary type to become a little faster and we can keep the the original keys (not upper cased) in the dictionary. Dictionary<string, string> DictTable = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase); void AddDict(string key, string value) { DictTable.Add(key, value); } Many people do not user the other ctors of Dictionary because they do shy away from the overhead of writing their own comparer. They do not know that .NET has for strings already predefined comparers at hand which you can directly use. Today in the many core area we do use threads all over the place. Sometimes things break in subtle ways but most of the time it is sufficient to place a lock around the offender. Threading has become so mainstream that it may sound weird that in the year 2000 some guy got a huge incentive for the idea to reduce the time to process calibration data from 12 hours to 6 hours by using two threads on a dual core machine. Threading does make it easy to become faster at the expense of correctness. Correct and scalable multithreading can be arbitrarily hard to achieve depending on the problem you are trying to solve. Lets suppose we want to process millions of items with two threads and count the processed items processed by all threads. A typical beginners code might look like this: int Counter; void IJustLearnedToUseThreads() { var t1 = new Thread(ThreadWorkMethod); t1.Start(); var t2 = new Thread(ThreadWorkMethod); t2.Start(); t1.Join(); t2.Join(); if (Counter != 2 * Increments) throw new Exception("Hmm " + Counter + " != " + 2 * Increments); } const int Increments = 10 * 1000 * 1000; void ThreadWorkMethod() { for (int i = 0; i < Increments; i++) { Counter++; } } It does throw an exception with the message e.g. “Hmm 10.222.287 != 20.000.000” and does never finish. The code does fail because the assumption that Counter++ is an atomic operation is wrong. The ++ operator is just a shortcut for Counter = Counter + 1 This does involve reading the counter from a memory location into the CPU, incrementing value on the CPU and writing the new value back to the memory location. When we do look at the generated assembly code we will see only inc dword ptr [ecx+10h] which is only one instruction. Yes it is one instruction but it is not atomic. All modern CPUs have several layers of caches (L1,L2,L3) which try to hide the fact how slow actual main memory accesses are. Since cache is just another word for redundant copy it can happen that one CPU does read a value from main memory into the cache, modifies it and write it back to the main memory. The problem is that at least the L1 cache is not shared between CPUs so it can happen that one CPU does make changes to values which did change in meantime in the main memory. From the exception you can see we did increment the value 20 million times but half of the changes were lost because we did overwrite the already changed value from the other thread. This is a very common case and people do learn to protect their  data with proper locking.   void Intermediate() { var time = Stopwatch.StartNew(); Action acc = ThreadWorkMethod_Intermediate; var ar1 = acc.BeginInvoke(null, null); var ar2 = acc.BeginInvoke(null, null); ar1.AsyncWaitHandle.WaitOne(); ar2.AsyncWaitHandle.WaitOne(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Intermediate did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Intermediate() { for (int i = 0; i < Increments; i++) { lock (this) { Counter++; } } } This is better and does use the .NET Threadpool to get rid of manual thread management. It does give the expected result but it can result in deadlocks because you do lock on this. This is in general a bad idea since it can lead to deadlocks when other threads use your class instance as lock object. It is therefore recommended to create a private object as lock object to ensure that nobody else can lock your lock object. When you read more about threading you will read about lock free algorithms. They are nice and can improve performance quite a lot but you need to pay close attention to the CLR memory model. It does make quite weak guarantees in general but it can still work because your CPU architecture does give you more invariants than the CLR memory model. For a simple counter there is an easy lock free alternative present with the Interlocked class in .NET. As a general rule you should not try to write lock free algos since most likely you will fail to get it right on all CPU architectures. void Experienced() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); t1.Wait(); t2.Wait(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Experienced did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Experienced() { for (int i = 0; i < Increments; i++) { Interlocked.Increment(ref Counter); } } Since time does move forward we do not use threads explicitly anymore but the much nicer Task abstraction which was introduced with .NET 4 at 2010. It is educational to look at the generated assembly code. The Interlocked.Increment method must be called which does wondrous things right? Lets see: lock inc dword ptr [eax] The first thing to note that there is no method call at all. Why? Because the JIT compiler does know very well about CPU intrinsic functions. Atomic operations which do lock the memory bus to prevent other processors to read stale values are such things. Second: This is the same increment call prefixed with a lock instruction. The only reason for the existence of the Interlocked class is that the JIT compiler can compile it to the matching CPU intrinsic functions which can not only increment by one but can also do an add, exchange and a combined compare and exchange operation. But be warned that the correct usage of its methods can be tricky. If you try to be clever and look a the generated IL code and try to reason about its efficiency you will fail. Only the generated machine code counts. Is this the best code we can write? Perhaps. It is nice and clean. But can we make it any faster? Lets see how good we are doing currently. Level Time in s IJustLearnedToUseThreads Flawed Code Intermediate 1,5 (lock) Experienced 0,3 (Interlocked.Increment) Master 0,1 (1,0 for int[2]) That lock free thing is really a nice thing. But if you read more about CPU cache, cache coherency, false sharing you can do even better. int[] Counters = new int[12]; // Cache line size is 64 bytes on my machine with an 8 way associative cache try for yourself e.g. 64 on more modern CPUs void Master() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Master, 0); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Master, Counters.Length - 1); t1.Wait(); t2.Wait(); Counter = Counters[0] + Counters[Counters.Length - 1]; if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Master did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Master(object number) { int index = (int) number; for (int i = 0; i < Increments; i++) { Counters[index]++; } } The key insight here is to use for each core its own value. But if you simply use simply an integer array of two items, one for each core and add the items at the end you will be much slower than the lock free version (factor 3). Each CPU core has its own cache line size which is something in the range of 16-256 bytes. When you do access a value from one location the CPU does not only fetch one value from main memory but a complete cache line (e.g. 16 bytes). This means that you do not pay for the next 15 bytes when you access them. This can lead to dramatic performance improvements and non obvious code which is faster although it does have many more memory reads than another algorithm. So what have we done here? We have started with correct code but it was lacking knowledge how to use the .NET Base Class Libraries optimally. Then we did try to get fancy and used threads for the first time and failed. Our next try was better but it still had non obvious issues (lock object exposed to the outside). Knowledge has increased further and we have found a lock free version of our counter which is a nice and clean way which is a perfectly valid solution. The last example is only here to show you how you can get most out of threading by paying close attention to your used data structures and CPU cache coherency. Although we are working in a virtual execution environment in a high level language with automatic memory management it does pay off to know the details down to the assembly level. Only if you continue to learn and to dig deeper you can come up with solutions no one else was even considering. I have studied particle physics which does help at the digging deeper part. Have you ever tried to solve Quantum Chromodynamics equations? Compared to that the rest must be easy ;-). Although I am no longer working in the Science field I take pride in discovering non obvious things. This can be a very hard to find bug or a new way to restructure data to make something 10 times faster. Now I need to get some sleep ….

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  • Visual Studio Talk Show #119 is now online - Quand et dans quel contexte est-ce que adéquat est adéq

    - by guybarrette
    http://www.visualstudiotalkshow.com Joel Quimper: Quand et dans quel contexte est-ce que «adéquat» est «adéquat»? Nous discutons avec Joel Quimper des pratiques de développement et de la mauvaise habitude qui consiste à vouloir tout abstraire et tout généraliser. Un application offre une valeur réelle seulement lorsqu’elle est utilisée par des utilisateurs. Alors ou tracer la limite entre le sur-design, l'extensibilité et la réutilisabilité. Joel Quimper est un conseiller en architecture chez Microsoft Canada. Il travaille essentiellement avec les architectes des grandes entreprises de l'Est du Canada pour aider leur organisation à réaliser leur plein potentiel. Joel possède une vaste expérience dans la conception de solutions orientées service en utilisant les services web. Il est passionné par l'interopérabilité avec la plateforme .NET. Avant de rejoindre Microsoft, il a travaillé 10 ans pour IBM Canada dans plusieurs rôles. Plus récemment, il a travaillé comme architecte d'intégration WebSphere. Il a travaillé avec plusieurs clients dans la mise en œuvre réussie de solutions SOA. var addthis_pub="guybarrette";

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