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• mixing different technologies using ARR reverse proxy

  - by Jaepetto

  I'm currently trying to put together a proof of concept on mixing various technologies onto one web site in order to ease migrations and add flexibility. The idea is to create one 'mashup' site behind an IIS 7.5 ARR reverse proxy. For the time being the ARR reverse proxy forwards all request to our main site. The request are as follow: client -> ARR: Get / ARR -> Server 1: Get / Server 1 -> ARR: 200: /index.htm ARR -> client: 200: /index.htm ...so far so good. Let's say, I want to add a new site (root of another server) as a subsite of my main website. a simple inbound rule does the trick: <rule name="sub1" stopProcessing="true"> <match url="^mySubsite(.*)" /> <conditions logicalGrouping="MatchAll" trackAllCaptures="false" /> <action type="Rewrite" url="http://server2/{R:1}" /> </rule> The requests now are: client -> ARR: Get /mySubsite ARR -> Server 2: Get / Server 2 -> ARR: 200: /index.htm ARR -> client: 200: /index.htm ... still ok. The issue comes when the site on server2 sends a redirection (e.g. to a login page). In the case of SharePoint, it will redirect the user to: /_layouts/Authenticate.aspx?Source=%2F ...which does not exists: client -> ARR: Get /mySubsite ARR -> Server 2: Get / Server 2 -> ARR: 301: /_layouts/Authenticate.aspx?Source=%2F ARR -> client: 301: /_layouts/Authenticate.aspx?Source=%2F client -> ARR: Get /_layouts/Authenticate.aspx?Source=%2F ARR -> client: 404: Not Found Does anyone know a way write the outbound rule to rewrite the response from server 2 "301: /_layouts/Authenticate.aspx?Source=%2F" to "301: /mySubsite/_layouts/Authenticate.aspx?Source=%2FmySubsite%2F"?

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• Need a script/batch/program that runs a command that won't be killed when the parent is killed

  - by billc.cn

  The scenario I use Zabbix to monitor my servers and recently I wanted to add some more metrics for the Windows ones. For security reasons, I used Zabbix's User Parameter feature, but it limits the execution of external commands to about 3 seconds. After that, the command is forcibly killed. I want to run some long run commands, so I used the trick from Zabbix's forum: run the command in the background, write the results to a file and use Zabbix to collect them. This is rather easy under *nix thanks to the "&" operator, but there is no such support in Windows' shell. To make things worse, when Zabbix kills forcibly kill the cmd.exe it used to evaluate the commands, all child processes die including the unfinished background tasks. Thus I need something that can sever all the ties with its children so they won't be affected in the cascading kill. What I've tried start and start /B - They do nothing as the child always die with the parent WScript.Shell.Run as in invis.vbs from StackOverflow - Sometimes work. If the wscript process is forcibly killed as opposed to quitting on its own, the children will die as well. hstart - similar results to invis.vbs At command - This requires you to set an absolution time for the task to run as opposed to an offset, so the code would be quite messy due to the limited shell scripting capability of Windows. (Edit) PsExec.exe from the SysInternals suite - It uses a service to launch the command, so it is not affected by the kill; however, it prints some banner and log info to StdErr and there's no switch to disable this. When I use 2>NUL to redirect them, Zabbix reports an error. After trying the above in different combinations, I noticed if I call hstart from invis.vbs, the command started by the former will be left alone as a parent-less process when invis.vbs is killed. However, since I need to redirect the output, the command I want to run is always in the form of cmd.exe /c ""command" "args"" >log. The vbs also removes all the quotes, so I have to encode the command with self-defined escape sequences. The end result involves about five levels of escaping/quoting, which is almost impossible to maintain. Anyone know any better solutions? Some requirements Any bat/vbs/js/Win32 binary is acceptable Better not require multiple levels of escaping No .Net (including PowerShell) because it is not installed

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• WCF REST on .Net 4.0

  - by AngelEyes

  A simple and straight forward article taken from: http://christopherdeweese.com/blog2/post/drop-the-soap-wcf-rest-and-pretty-uris-in-net-4 Drop the Soap: WCF, REST, and Pretty URIs in .NET 4 Years ago I was working in libraries when the Web 2.0 revolution began.  One of the things that caught my attention about early start-ups using the AJAX/REST/Web 2.0 model was how nice the URIs were for their applications.  Those were my first impressions of REST; pretty URIs.  Turns out there is a little more to it than that. REST is an architectural style that focuses on resources and structured ways to access those resources via the web.  REST evolved as an “anti-SOAP” movement, driven by developers who did not want to deal with all the complexity SOAP introduces (which is al lot when you don’t have frameworks hiding it all).  One of the biggest benefits to REST is that browsers can talk to rest services directly because REST works using URIs, QueryStrings, Cookies, SSL, and all those HTTP verbs that we don’t have to think about anymore. If you are familiar with ASP.NET MVC then you have been exposed to rest at some level.  MVC is relies heavily on routing to generate consistent and clean URIs.  REST for WCF gives you the same type of feel for your services.  Let’s dive in. WCF REST in .NET 3.5 SP1 and .NET 4 This post will cover WCF REST in .NET 4 which drew heavily from the REST Starter Kit and community feedback.  There is basic REST support in .NET 3.5 SP1 and you can also grab the REST Starter Kit to enable some of the features you’ll find in .NET 4. This post will cover REST in .NET 4 and Visual Studio 2010. Getting Started To get started we’ll create a basic WCF Rest Service Application using the new on-line templates option in VS 2010: When you first install a template you are prompted with this dialog: Dude Where’s my .Svc File? The WCF REST template shows us the new way we can simply build services.  Before we talk about what’s there, let’s look at what is not there: The .Svc File An Interface Contract Dozens of lines of configuration that you have to change to make your service work REST in .NET 4 is greatly simplified and leverages the Web Routing capabilities used in ASP.NET MVC and other parts of the web frameworks.  With REST in .NET 4 you use a global.asax to set the route to your service using the new ServiceRoute class.  From there, the WCF runtime handles dispatching service calls to the methods based on the Uri Templates. global.asax using System; using System.ServiceModel.Activation; using System.Web; using System.Web.Routing; namespace Blog.WcfRest.TimeService {     public class Global : HttpApplication     {         void Application_Start(object sender, EventArgs e)         {             RegisterRoutes();         }         private static void RegisterRoutes()         {             RouteTable.Routes.Add(new ServiceRoute("TimeService",                 new WebServiceHostFactory(), typeof(TimeService)));         }     } } The web.config contains some new structures to support a configuration free deployment.  Note that this is the default config generated with the template.  I did not make any changes to web.config. web.config <?xml version="1.0"?> <configuration>   <system.web>     <compilation debug="true" targetFramework="4.0" />   </system.web>   <system.webServer>     <modules runAllManagedModulesForAllRequests="true">       <add name="UrlRoutingModule" type="System.Web.Routing.UrlRoutingModule,            System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />     </modules>   </system.webServer>   <system.serviceModel>     <serviceHostingEnvironment aspNetCompatibilityEnabled="true"/>     <standardEndpoints>       <webHttpEndpoint>         <!--             Configure the WCF REST service base address via the global.asax.cs file and the default endpoint             via the attributes on the <standardEndpoint> element below         -->         <standardEndpoint name="" helpEnabled="true" automaticFormatSelectionEnabled="true"/>       </webHttpEndpoint>     </standardEndpoints>   </system.serviceModel> </configuration> Building the Time Service We’ll create a simple “TimeService” that will return the current time.  Let’s start with the following code: using System; using System.ServiceModel; using System.ServiceModel.Activation; using System.ServiceModel.Web; namespace Blog.WcfRest.TimeService {     [ServiceContract]     [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]     [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall)]     public class TimeService     {         [WebGet(UriTemplate = "CurrentTime")]         public string CurrentTime()         {             return DateTime.Now.ToString();         }     } } The endpoint for this service will be http://[machinename]:[port]/TimeService.  To get the current time http://[machinename]:[port]/TimeService/CurrentTime will do the trick. The Results Are In Remember That Route In global.asax? Turns out it is pretty important.  When you set the route name, that defines the resource name starting after the host portion of the Uri. Help Pages in WCF 4 Another feature that came from the starter kit are the help pages.  To access the help pages simply append Help to the end of the service’s base Uri. Dropping the Soap Having dabbled with REST in the past and after using Soap for the last few years, the WCF 4 REST support is certainly refreshing.  I’m currently working on some REST implementations in .NET 3.5 and VS 2008 and am looking forward to working on REST in .NET 4 and VS 2010.

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• C#: System.Lazy&lt;T&gt; and the Singleton Design Pattern

  - by James Michael Hare

  So we've all coded a Singleton at one time or another.  It's a really simple pattern and can be a slightly more elegant alternative to global variables.  Make no mistake, Singletons can be abused and are often over-used -- but occasionally you find a Singleton is the most elegant solution. For those of you not familiar with a Singleton, the basic Design Pattern is that a Singleton class is one where there is only ever one instance of the class created.  This means that constructors must be private to avoid users creating their own instances, and a static property (or method in languages without properties) is defined that returns a single static instance. 1: public class Singleton 2: { 3: // the single instance is defined in a static field 4: private static readonly Singleton _instance = new Singleton(); 5:  6: // constructor private so users can't instantiate on their own 7: private Singleton() 8: { 9: } 10:  11: // read-only property that returns the static field 12: public static Singleton Instance 13: { 14: get 15: { 16: return _instance; 17: } 18: } 19: } This is the most basic singleton, notice the key features: Static readonly field that contains the one and only instance. Constructor is private so it can only be called by the class itself. Static property that returns the single instance. Looks like it satisfies, right?  There's just one (potential) problem.  C# gives you no guarantee of when the static field _instance will be created.  This is because the C# standard simply states that classes (which are marked in the IL as BeforeFieldInit) can have their static fields initialized any time before the field is accessed.  This means that they may be initialized on first use, they may be initialized at some other time before, you can't be sure when. So what if you want to guarantee your instance is truly lazy.  That is, that it is only created on first call to Instance?  Well, there's a few ways to do this.  First we'll show the old ways, and then talk about how .Net 4.0's new System.Lazy<T> type can help make the lazy-Singleton cleaner. Obviously, we could take on the lazy construction ourselves, but being that our Singleton may be accessed by many different threads, we'd need to lock it down. 1: public class LazySingleton1 2: { 3: // lock for thread-safety laziness 4: private static readonly object _mutex = new object(); 5:  6: // static field to hold single instance 7: private static LazySingleton1 _instance = null; 8:  9: // property that does some locking and then creates on first call 10: public static LazySingleton1 Instance 11: { 12: get 13: { 14: if (_instance == null) 15: { 16: lock (_mutex) 17: { 18: if (_instance == null) 19: { 20: _instance = new LazySingleton1(); 21: } 22: } 23: } 24:  25: return _instance; 26: } 27: } 28:  29: private LazySingleton1() 30: { 31: } 32: } This is a standard double-check algorithm so that you don't lock if the instance has already been created.  However, because it's possible two threads can go through the first if at the same time the first time back in, you need to check again after the lock is acquired to avoid creating two instances. Pretty straightforward, but ugly as all heck.  Well, you could also take advantage of the C# standard's BeforeFieldInit and define your class with a static constructor.  It need not have a body, just the presence of the static constructor will remove the BeforeFieldInit attribute on the class and guarantee that no fields are initialized until the first static field, property, or method is called.   1: public class LazySingleton2 2: { 3: // because of the static constructor, this won't get created until first use 4: private static readonly LazySingleton2 _instance = new LazySingleton2(); 5:  6: // Returns the singleton instance using lazy-instantiation 7: public static LazySingleton2 Instance 8: { 9: get { return _instance; } 10: } 11:  12: // private to prevent direct instantiation 13: private LazySingleton2() 14: { 15: } 16:  17: // removes BeforeFieldInit on class so static fields not 18: // initialized before they are used 19: static LazySingleton2() 20: { 21: } 22: } Now, while this works perfectly, I hate it.  Why?  Because it's relying on a non-obvious trick of the IL to guarantee laziness.  Just looking at this code, you'd have no idea that it's doing what it's doing.  Worse yet, you may decide that the empty static constructor serves no purpose and delete it (which removes your lazy guarantee).  Worse-worse yet, they may alter the rules around BeforeFieldInit in the future which could change this. So, what do I propose instead?  .Net 4.0 adds the System.Lazy type which guarantees thread-safe lazy-construction.  Using System.Lazy<T>, we get: 1: public class LazySingleton3 2: { 3: // static holder for instance, need to use lambda to construct since constructor private 4: private static readonly Lazy<LazySingleton3> _instance 5: = new Lazy<LazySingleton3>(() => new LazySingleton3()); 6:  7: // private to prevent direct instantiation. 8: private LazySingleton3() 9: { 10: } 11:  12: // accessor for instance 13: public static LazySingleton3 Instance 14: { 15: get 16: { 17: return _instance.Value; 18: } 19: } 20: } Note, you need your lambda to call the private constructor as Lazy's default constructor can only call public constructors of the type passed in (which we can't have by definition of a Singleton).  But, because the lambda is defined inside our type, it has access to the private members so it's perfect. Note how the Lazy<T> makes it obvious what you're doing (lazy construction), instead of relying on an IL generation side-effect.  This way, it's more maintainable.  Lazy<T> has many other uses as well, obviously, but I really love how elegant and readable it makes the lazy Singleton.

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• Ask How-To Geek: Dropbox in the Start Menu, Understanding Symlinks, and Ripping TV Series DVDs

  - by Jason Fitzpatrick

  This week we take a look at how to incorporate Dropbox into your Windows Start Menu, understanding and using symbolic links, and how to rip your TV series DVDs right to unique and high-quality episode files. Once a week we dip into our reader mailbag and help readers solve their problems, sharing the useful solutions with you in the process. Read on to see our fixes for this week’s reader dilemmas. Add Drobox to Your Start Menu Dear How-To Geek, I use Dropbox all the time and would like to add it right onto my start menu along side the other major shortcuts like Documents, Pictures, etc. It seems like adding Dropbox into the menu should be part of the Dropbox installation package! Sincerely, Dropboxing in Des Moines Dear Dropboxing, We agree, it would be a nice installation option. As it stands you’re going to have to do a little simple hacking to get Dropbox nestled neatly into your start menu. The hack isn’t super elegant but when you’re done you’ll have the link you want and it’ll look like it was there all along. Check out this step-by-step guide here in order to take an existing Library shortcut and rework it to be a Dropbox link. Understanding and Using Symbolic Links Dear How-To Geek, I was talking to a coworker the other day about an issue I’d been having with a media center application I’m running. He suggested using symbolic links to better organize my media and make it easier for the application to access my collection. I had no idea what he was talking about and never got a chance to bug him about it later. Can you clear up this whole symbolic links business for me? I’ve been using computers for years and I’ve never even heard of it! Sincerely, Symbolic Who? Dear Symbolic, Symbolic links aren’t commonly used by many Windows users which is why you likely haven’t run into the concept. Symbolic links are essentially supercharged shortcuts—the newly introduced Windows library system is really just a type of symbolic link system. You can use symbolic links to do all sorts of neat stuff like link folders to your Dropbox folder, organize media, and more. The concept of symbolic links is pretty simple but the execution can be really tricky. We’d suggest reading over our guide to creating symbolic links in Windows 7, Windows XP, and Ubunutu to get a clearer idea what you’re getting into. Rip Your TV DVDs into Handy Episode Files Dear How-To Geek, My wife got me an iPod for Christmas and I still haven’t got around to filling it up. I have tons of entire TV show seasons on DVD and would like to get them on the iPod but I have absolutely no idea where to start. How do I get the shows off the discs? I thought it would be as easy to import the TV shows into iTunes as it is to import tracks off a CD but I was totally wrong. I tried downloading some applications to rip them but those didn’t work at all. Very frustrating! Surely there is an easy and/or automated way to do this, right? Sincerely, Free My DVDs Dear DVDs, Oh man is this a frustration we can relate to. It’s inordinately difficult to get movies and TV shows off physical media and into digital (and portable media player-friendly) formats. There are a multitude of ways to rip DVDs and quite a few applications out there (some good, some mediocre, and some outright malware). We’d recommend a two-part punch to solve your ripping woes. You’ll need a copy of DVDFab to strip away the protections on the discs and rip the disc and Handbrake to load the disc image and convert the files. It’s not quite as smooth as the CD-to-iTunes workflow but it’s still pretty easy. Check out all the steps and settings you’ll want to toggle here. Have a question you want to put before the How-To Geek staff? Shoot us an email at [email protected] and then keep an eye out for a solution in the Ask How-To Geek column. Latest Features How-To Geek ETC Internet Explorer 9 RC Now Available: Here’s the Most Interesting New Stuff Here’s a Super Simple Trick to Defeating Fake Anti-Virus Malware How to Change the Default Application for Android Tasks Stop Believing TV’s Lies: The Real Truth About "Enhancing" Images The How-To Geek Valentine’s Day Gift Guide Inspire Geek Love with These Hilarious Geek Valentines Google’s New Personal Blocklist Extension Kills Search Engine Spam KeyCounter Tracks Your Keystrokes and Mouse Clicks Add Custom LED Ambient Lighting to Your PC or Media Center The Trackor Monitors Amazon Prices; Integrates with Chrome, Firefox, and Safari Four Awesome TRON Legacy Themes for Chrome and Iron Anger is Illogical – Old School Style Instructional Video [Star Trek Mashup]

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• Forcing an External Activation with Service Broker

  - by Davide Mauri

  In these last days I’ve been working quite a lot with Service Broker, a technology I’m really happy to work with, since it can give a lot of satisfaction. The scale-out solution one can easily build is simply astonishing. I’m helping a company to build a very scalable and – yet almost inexpensive – invoicing system that has to be able to scale out using commodity hardware. To offload the work from the main server to satellite “compute nodes” (yes, I’ve borrowed this term from PDW) we’re using Service Broker and the External Activator application available in the SQL Server Feature Pack. For those who are not used to work with SSB, the External Activation is a feature that allows you to intercept the arrival of a message in a queue right from your application code. http://msdn.microsoft.com/en-us/library/ms171617.aspx (Look for “Event-Based Activation”) In order to make life even more easier, Microsoft released the External Activation application that saves you even from writing even this code. http://blogs.msdn.com/b/sql_service_broker/archive/tags/external+activator/ The External Activator application can be configured to execute your own application so that each time a message – an invoice in my case – arrives in the target queue, the invoking application is executed and the invoice is calculated. The very nice feature of External Activator is that it can automatically execute as many configured application in order to process as many messages as your system can handle.  This also a lot of create a scale-out solution, leaving to the developer only a fraction of the problems that usually came with asynchronous programming. Developers are also shielded from Service Broker since everything can be encapsulated in Stored Procedures, so that – for them – developing such scale-out asynchronous solution is not much more complex than just executing a bunch of Stored Procedures. Now, if everything works correctly, you don’t have to bother of anything else. You put messages in the queue and your application, invoked by the External Activator, process them. But what happen if for some reason your application fails to process the messages. For examples, it crashes? The message is safe in the queue so you just need to process it again. But your application is invoked by the External Activator application, so now the question is, how do you wake up that app? Service Broker will engage the activation process only if certain conditions are met: http://msdn.microsoft.com/en-us/library/ms171601.aspx But how we can invoke the activation process manually, without having to wait for another message to arrive (the arrival of a new message is a condition that can fire the activation process)? The “trick” is to do manually with the activation process does: sending a system message to a queue in charge of handling External Activation messages: declare @conversationHandle uniqueidentifier; declare @n xml = N' <EVENT_INSTANCE>   <EventType>QUEUE_ACTIVATION</EventType>   <PostTime>' + CONVERT(CHAR(24),GETDATE(),126) + '</PostTime>   <SPID>' + CAST(@@SPID AS VARCHAR(9)) + '</SPID>   <ServerName>[your_server_name]</ServerName>   <LoginName>[your_login_name]</LoginName>   <UserName>[your_user_name]</UserName>   <DatabaseName>[your_database_name]</DatabaseName>   <SchemaName>[your_queue_schema_name]</SchemaName>   <ObjectName>[your_queue_name]</ObjectName>   <ObjectType>QUEUE</ObjectType> </EVENT_INSTANCE>' begin dialog conversation     @conversationHandle from service        [<your_initiator_service_name>] to service          '<your_event_notification_service>' on contract         [http://schemas.microsoft.com/SQL/Notifications/PostEventNotification] with     encryption = off,     lifetime = 6000 ; send on conversation     @conversationHandle message type     [http://schemas.microsoft.com/SQL/Notifications/EventNotification] (@n) ;     end conversation @conversationHandle; That’s it! Put the code in a Stored Procedure and you can add to your application a button that says “Force Queue Processing” (or something similar) in order to start the activation process whenever you need it (which should not occur too frequently but it may happen). PS I know that the “fire-and-forget” (ending the conversation without waiting for an answer) technique is not a best practice, but in this case I don’t see how it can hurts so I decided to stay very close to the KISS principle []

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• How to Use An Antivirus Boot Disc or USB Drive to Ensure Your Computer is Clean

  - by Chris Hoffman

  If your computer is infected with malware, running an antivirus within Windows may not be enough to remove it. If your computer has a rootkit, the malware may be able to hide itself from your antivirus software. This is where bootable antivirus solutions come in. They can clean malware from outside the infected Windows system, so the malware won’t be running and interfering with the clean-up process. The Problem With Cleaning Up Malware From Within Windows Standard antivirus software runs within Windows. If your computer is infected with malware, the antivirus software will have to do battle with the malware. Antivirus software will try to stop the malware and remove it, while the malware will attempt to defend itself and shut down the antivirus. For really nasty malware, your antivirus software may not be able to fully remove it from within Windows. Rootkits, a type of malware that hides itself, can be even trickier. A rootkit could load at boot time before other Windows components and prevent Windows from seeing it, hide its processes from the task manager, and even trick antivirus applications into believing that the rootkit isn’t running. The problem here is that the malware and antivirus are both running on the computer at the same time. The antivirus is attempting to fight the malware on its home turf — the malware can put up a fight. Why You Should Use an Antivirus Boot Disc Antivirus boot discs deal with this by approaching the malware from outside Windows. You boot your computer from a CD or USB drive containing the antivirus and it loads a specialized operating system from the disc. Even if your Windows installation is completely infected with malware, the special operating system won’t have any malware running within it. This means the antivirus program can work on the Windows installation from outside it. The malware won’t be running while the antivirus tries to remove it, so the antivirus can methodically locate and remove the harmful software without it interfering. Any rootkits won’t be able to set up the tricks they use at Windows boot time to hide themselves from the rest o the operating system. The antivirus will be able to see the rootkits and remove them. These tools are often referred to as “rescue disks.” They’re meant to be used when you need to rescue a hopelessly infected system. Bootable Antivirus Options As with any type of antivirus software, you have quite a few options. Many antivirus companies offer bootable antivirus systems based on their antivirus software. These tools are generally free, even when they’re offered by companies that specialized in paid antivirus solutions. Here are a few good options: avast! Rescue Disk – We like avast! for offering a capable free antivirus with good detection rates in independent tests. avast! now offers the ability to create an antivirus boot disc or USB drive. Just navigate to the Tools -> Rescue Disk option in the avast! desktop application to create bootable media. BitDefender Rescue CD – BitDefender always seems to receive good scores in independent tests, and the BitDefender Rescue CD offers the same antivirus engine in the form of a bootable disc. Kaspersky Rescue Disk – Kaspersky also receives good scores in independent tests and offers its own antivirus boot disc. These are just a handful of options. If you prefer another antivirus for some reason — Comodo, Norton, Avira, ESET, or almost any other antivirus product — you’ll probably find that it offers its own system rescue disk. How to Use an Antivirus Boot Disc Using an antivirus boot disc or USB drive is actually pretty simple. You’ll just need to find the antivirus boot disc you want to use and burn it to disc or install it on a USB drive. You can do this part on any computer, so you can create antivirus boot media on a clean computer and then take it to an infected computer. Insert the boot media into the infected computer and then reboot. The computer should boot from the removable media and load the secure antivirus environment. (If it doesn’t, you may need to change the boot order in your BIOS or UEFI firmware.) You can then follow the instructions on your screen to scan your Windows system for malware and remove it. No malware will be running in the background while you do this. Antivirus boot discs are useful because they allow you to detect and clean malware infections from outside an infected operating system. If the operating system is severely infected, it may not be possible to remove — or even detect — all the malware from within it. Image Credit: aussiegall on Flickr     

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• Top 4 Lame Tech Blogging Posts

  - by jkauffman

  From a consumption point of view, tech blogging is a great resource for one-off articles on niche subjects. If you spend any time reading tech blogs, you may find yourself running into several common, useless types of posts tech bloggers slip into. Some of these lame posts may just be natural due to common nerd psychology, and some others are probably due to lame, lemming-like laziness. I’m sure I’ll do my fair share of fitting the mold, but I quickly get bored when I happen upon posts that hit these patterns without any real purpose or personal touches. 1. The Content Regurgitation Posts This is a common pattern fueled by the starving pan-handlers in the web traffic economy. These are posts that are terse opinions or addendums to an existing post. I commonly see these involve huge block quotes from the linked article which almost always produces over 50% of the post itself. I’ve accidentally gone to these posts when I’m knowingly only interested in the source material. Web links can degrade as well, so if the source link is broken, then, well, I’m pretty steamed. I see this occur with simple opinions on technologies, Stack Overflow solutions, or various tech news like posts from Microsoft. It’s not uncommon to go to the linked article and see the author announce that he “added a blog post” as a response or summary of the topic. This is just rude, but those who do it are probably aware of this. It’s a matter of winning that sweet, juicy web traffic. I doubt this leeching is fooling anybody these days. I would like to rally human dignity and urge people to avoid these types of posts, and just leave a comment on the source material. 2. The “Sorry I Haven’t Posted In A While” Posts This one is far too common. You’ll most likely see this quote somewhere in the body of the offending post: I have been really busy. If the poster is especially guilt-ridden, you’ll see a few volleys of excuses. Here are some common reasons I’ve seen, which I’ll list from least to most painfully awkward. Out of town Vague allusions to personal health problems (these typically includes phrases like “sick”, “treatment'”, and “all better now!”) “Personal issues” (which I usually read as "divorce”) Graphic or specific personal health problems (maximum awkwardness potential is achieved if you see links to charity fund websites) I can’t help but to try over-analyzing why this occurs. Personally, I see this an an amalgamation of three plain factors: Life happens Us nerds are duty-driven, and driven to guilt at personal inefficiencies Tech blogs can become personal journals I don’t think we can do much about the first two, but on the third I think we could certainly contain our urges. I’m a pretty boring guy and, whether or I like it or not, I have an unspoken duty to protect the world from hearing about my unremarkable existence. Nobody cares what kind of sandwich I’m eating. Similarly, if I disappear for a while, it’s unlikely that anybody who happens upon my blog would care why. Rest assured, if I stop posting for a while due to a vasectomy, you will be the first to know. 3. The “At A Conference”, or “Conference Review” Posts I don’t know if I’m like everyone else on this one, but I have never been successfully interested in these posts. It even sounds like a good idea: if I can’t make it to a particular conference (like the KCDC this year), wouldn’t I be interested in a concentrated summary of events? Apparently, no! Within this realm, I’ve never read a post by a blogger that held my interest. What really baffles is is that, for whatever reason, I am genuinely engaged and interested when talking to someone in person regarding the same topic. I have noticed the same phenomenon when hearing about others’ vacations. If someone sends me an email about their vacation, I gloss over it and forget about it quickly. In contrast, if I’m speaking to that individual in person about their vacation, I’m actually interested. I’m unsure why the written medium eradicates the intrigue. I was raised by a roaming pack of friendly wild video games, so that may be a factor. 4. The “Top X Number of Y’s That Z” Posts I’ve seen this one crop up a lot more in the past few of years. Here are some fabricated examples: 5 Easy Ways to Improve Your Code Top 7 Good Habits Programmers Learn From Experience The 8 Things to Consider When Giving Estimates Top 4 Lame Tech Blogging Posts These are attention-grabbing headlines, and I’d assume they rack up hits. In fact, I enjoy a good number of these. But, I’ve been drawn to articles like this just to find an endless list of identically formatted posts on the blog’s archive sidebar. Often times these posts have overlapping topics, too. These types of posts give the impression that the author has given thought to prioritize and organize the points as a result of a comprehensive consideration of a particular topic. Did the author really weigh all the possibilities when identifying the “Top 4 Lame Tech Blogging Patterns”? Unfortunately, probably not. What a tool. To reiterate, I still enjoy the format, but I feel it is abused. Nowadays, I’m pretty skeptical when approaching posts in this format. If these trends continue, my brain will filter these blog posts out just as effectively as it ignores the encroaching “do xxx with this one trick” advertisements. Conclusion To active blog readers, I hope my guide has served you precious time in being able to identify lame blog posts at a glance. Save time and energy by skipping over the chaff of the internet! And if you author a blog, perhaps my insight will help you to avoid the occasional urge to produce these needless filler posts.

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• Programmatically use a server as the Build Server for multiple Project Collections

  Important: With this post you create an unsupported scenario by Microsoft. It will break your support for this server with Microsoft. So handle with care. I am the administrator an a TFS environment with a lot of Project Collections. In the supported configuration of Microsoft 2010 you need one Build Controller per Project Collection, and it is not supported to have multiple Build Controllers installed. Jim Lamb created a post how you can modify your system to change this behaviour. But since I have so many Project Collections, I automated this with the API of TFS. When you install a new build server via the UI, you do the following steps Register the build service (with this you hook the windows server into the build server environment) Add a new build controller Add a new build agent So in pseudo code, the code would look like foreach (projectCollection in GetAllProjectCollections) {       CreateNewWindowsService();       RegisterService();       AddNewController();       AddNewAgent(); } The following code fragements show you the most important parts of the method implementations. Attached is the full project. CreateNewWindowsService We create a new windows service with the SC command via the Diagnostics.Process class:             var pi = new ProcessStartInfo("sc.exe")                         {                             Arguments =                                 string.Format(                                     "create \"{0}\" start= auto binpath= \"C:\\Program Files\\Microsoft Team Foundation Server 2010\\Tools\\TfsBuildServiceHost.exe              /NamedInstance:{0}\" DisplayName= \"Visual Studio Team Foundation Build Service Host ({1})\"",                                     serviceHostName, tpcName)                         };            Process.Start(pi);             pi.Arguments = string.Format("failure {0} reset= 86400 actions= restart/60000", serviceHostName);            Process.Start(pi); RegisterService The trick in this method is that we set the NamedInstance static property. This property is Internal, so we need to set it through reflection. To get information on these you need nice Microsoft friends and the .Net reflector .             // Indicate which build service host instance we are using            typeof(BuildServiceHostUtilities).Assembly.GetType("Microsoft.TeamFoundation.Build.Config.BuildServiceHostProcess").InvokeMember("NamedInstance",              System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.SetProperty | System.Reflection.BindingFlags.Static, null, null, new object[] { serviceName });             // Create the build service host            serviceHost = buildServer.CreateBuildServiceHost(serviceName, endPoint);            serviceHost.Save();             // Register the build service host            BuildServiceHostUtilities.Register(serviceHost, user, password); AddNewController and AddNewAgent Once you have the BuildServerHost, the rest is pretty straightforward. There are methods on the BuildServerHost to modify the controllers and the agents                 controller = serviceHost.CreateBuildController(controllerName);                 agent = controller.ServiceHost.CreateBuildAgent(agentName, buildDirectory, controller);                controller.AddBuildAgent(agent); You have now seen the highlights of the application. If you need it and want to have sample information when you work in this area, download the app TFS2010_RegisterBuildServerToTPCs

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• Can't install wine (or ia32-libs) in Ubuntu 12.10 64 bit

  - by carestad

  As already pointed out here, people seems to have issues with installing wine in the latest version of Ubuntu. I'm suspecting this only happens with 64 bit users. For example, when trying to install wine, wine1.4, wine1.4:i386, wine1.5, wine1.5:i386, ia32-libs or ia32-libs:i386 with apt-get, I get a lot of dependency errors. Doing a sudo apt-get -f install doesn't seem to do the trick, neither does using aptitude. The errors I get is normally that the packages depend on some :i386 package, but installing those manually doesn't work either because they also have dependency issues (isn't APT supposed to do this automatically?!). I also downloaded CrossOver today and tried installing the .deb manually, but the dependency issues show up there as well. When running sudo apt-get -f install after trying to install the CrossOver .deb, apt-get wants to purge the following packages: ia32-crossover intel-gpu-tools libdrm-nouveau2 libgl1-mesa-dri libva-x11-1 ubuntu-desktop vlc xorg xserver-xorg-video-ati xserver-xorg-video-intel xserver-xorg-video-modesetting xserver-xorg-video-openchrome xserver-xorg-video-radeon xserver-xorg-video-vmware What I've tried so far (and didn't work): Installing synaptic, reloading my repositories, searching for ia32 and installing ia32-libs. Using Ubuntu Software Center to install Wine and ia32-libs. Using apt-get and aptitude to install all the differend varieties of the wine packages, both with and without the :i386 and -amd64 suffixes in package names. Disabling the universe and multiverse repos, run a sudo apt-get update and then re-enable them again. Boot a newly downloaded Ubuntu 12.10 x64 live USB and try to install all the different packages there. What I haven't tried (yet): Boot a newly downloaded Ubuntu 12.10 x32 image and try to install wine there (I'm just guessing that will work). Reinstall Ubuntu. Throw my computer out a window. wine alexander@cosmo:~$ LANGUAGE=en_US sudo apt-get install wine Reading package lists... Done Building dependency tree Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: wine : Depends: wine1.5 but it is not going to be installed E: Unable to correct problems, you have held broken packages. wine-1.4 alexander@cosmo:~$ LANGUAGE=en_US sudo apt-get install wine1.4 (...) The following packages have unmet dependencies: wine1.4 : Depends: wine1.4-i386 (= 1.4.1-0ubuntu1) E: Unable to correct problems, you have held broken packages. wine-1.4:i386 alexander@cosmo:~$ LANGUAGE=en_US sudo apt-get install wine1.4:i386 (...) The following packages have unmet dependencies: libaudio2:i386 : Depends: libxt6:i386 but it is not going to be installed libqtgui4:i386 : Depends: libsm6:i386 but it is not going to be installed libunity-webapps0 : Depends: unity-webapps-service but it is not going to be installed openssh-client : Depends: adduser (>= 3.10) but it is not going to be installed Depends: passwd ssh : Depends: openssh-server wine1.4:i386 : Depends: wine1.4-i386:i386 (= 1.4.1-0ubuntu1) Depends: binfmt-support:i386 (>= 1.1.2) Depends: procps:i386 Recommends: cups-bsd:i386 Recommends: gnome-exe-thumbnailer:i386 but it is not installable or kde-runtime:i386 but it is not going to be installed Recommends: ttf-droid:i386 but it is not installable Recommends: ttf-liberation:i386 but it is not installable Recommends: ttf-mscorefonts-installer:i386 Recommends: ttf-umefont:i386 but it is not installable Recommends: ttf-unfonts-core:i386 but it is not installable Recommends: ttf-wqy-microhei:i386 but it is not installable Recommends: winbind:i386 Recommends: winetricks:i386 but it is not going to be installed Recommends: xdg-utils:i386 but it is not installable E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages. wine-1.5 alexander@cosmo:~$ sudo apt-get install wine1.5 (...) The following packages have unmet dependencies: wine1.5 : Depends: wine1.5-i386 (= 1.5.16-0ubuntu1) E: Unable to correct problems, you have held broken packages. wine-1.5:i386 alexander@cosmo:~$ sudo apt-get install wine1.5:i386 (...) The following packages have unmet dependencies: libaudio2:i386 : Depends: libxt6:i386 but it is not going to be installed libqtgui4:i386 : Depends: libsm6:i386 but it is not going to be installed libunity-webapps0 : Depends: unity-webapps-service but it is not going to be installed openssh-client : Depends: adduser (>= 3.10) but it is not going to be installed Depends: passwd ssh : Depends: openssh-server wine1.5:i386 : Depends: wine1.5-i386:i386 (= 1.5.16-0ubuntu1) but it is not going to be installed Depends: binfmt-support:i386 (>= 1.1.2) Depends: procps:i386 Recommends: cups-bsd:i386 Recommends: gnome-exe-thumbnailer:i386 but it is not installable or kde-runtime:i386 but it is not going to be installed Recommends: ttf-droid:i386 but it is not installable Recommends: ttf-liberation:i386 but it is not installable Recommends: ttf-mscorefonts-installer:i386 Recommends: ttf-umefont:i386 but it is not installable Recommends: ttf-unfonts-core:i386 but it is not installable Recommends: ttf-wqy-microhei:i386 but it is not installable Recommends: winbind:i386 Recommends: winetricks:i386 but it is not going to be installed Recommends: xdg-utils:i386 but it is not installable E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages. ia32-libs alexander@cosmo:~$ sudo apt-get install ia32-libs (...) The following packages have unmet dependencies: ia32-libs : Depends: ia32-libs-multiarch E: Unable to correct problems, you have held broken packages. ia32-libs:i386 alexander@cosmo:~$ sudo apt-get install ia32-libs:i386 (...) Package ia32-libs:i386 is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source However the following packages replace it: lib32z1 lib32ncurses5 lib32bz2-1.0 lib32asound2 E: Package 'ia32-libs:i386' has no installation candidate

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• Rendering ASP.NET MVC Razor Views outside of MVC revisited

  - by Rick Strahl

  Last year I posted a detailed article on how to render Razor Views to string both inside of ASP.NET MVC and outside of it. In that article I showed several different approaches to capture the rendering output. The first and easiest is to use an existing MVC Controller Context to render a view by simply passing the controller context which is fairly trivial and I demonstrated a simple ViewRenderer class that simplified the process down to a couple lines of code. However, if no Controller Context is available the process is not quite as straight forward and I referenced an old, much more complex example that uses my RazorHosting library, which is a custom self-contained implementation of the Razor templating engine that can be hosted completely outside of ASP.NET. While it works inside of ASP.NET, it’s an awkward solution when running inside of ASP.NET, because it requires a bit of setup to run efficiently.Well, it turns out that I missed something in the original article, namely that it is possible to create a ControllerContext, if you have a controller instance, even if MVC didn’t create that instance. Creating a Controller Instance outside of MVCThe trick to make this work is to create an MVC Controller instance – any Controller instance – and then configure a ControllerContext through that instance. As long as an HttpContext.Current is available it’s possible to create a fully functional controller context as Razor can get all the necessary context information from the HttpContextWrapper().The key to make this work is the following method:/// <summary> /// Creates an instance of an MVC controller from scratch /// when no existing ControllerContext is present /// </summary> /// <typeparam name="T">Type of the controller to create</typeparam> /// <returns>Controller Context for T</returns> /// <exception cref="InvalidOperationException">thrown if HttpContext not available</exception> public static T CreateController<T>(RouteData routeData = null) where T : Controller, new() { // create a disconnected controller instance T controller = new T(); // get context wrapper from HttpContext if available HttpContextBase wrapper = null; if (HttpContext.Current != null) wrapper = new HttpContextWrapper(System.Web.HttpContext.Current); else throw new InvalidOperationException( "Can't create Controller Context if no active HttpContext instance is available."); if (routeData == null) routeData = new RouteData(); // add the controller routing if not existing if (!routeData.Values.ContainsKey("controller") && !routeData.Values.ContainsKey("Controller")) routeData.Values.Add("controller", controller.GetType().Name .ToLower() .Replace("controller", "")); controller.ControllerContext = new ControllerContext(wrapper, routeData, controller); return controller; }This method creates an instance of a Controller class from an existing HttpContext which means this code should work from anywhere within ASP.NET to create a controller instance that’s ready to be rendered. This means you can use this from within an Application_Error handler as I needed to or even from within a WebAPI controller as long as it’s running inside of ASP.NET (ie. not self-hosted). Nice.So using the ViewRenderer class from the previous article I can now very easily render an MVC view outside of the context of MVC. Here’s what I ended up in my Application’s custom error HttpModule: protected override void OnDisplayError(WebErrorHandler errorHandler, ErrorViewModel model) { var Response = HttpContext.Current.Response; Response.ContentType = "text/html"; Response.StatusCode = errorHandler.OriginalHttpStatusCode; var context = ViewRenderer.CreateController<ErrorController>().ControllerContext; var renderer = new ViewRenderer(context); string html = renderer.RenderView("~/Views/Shared/GenericError.cshtml", model); Response.Write(html); }That’s pretty sweet, because it’s now possible to use ViewRenderer just about anywhere in any ASP.NET application, not only inside of controller code. This also allows the constructor for the ViewRenderer from the last article to work without a controller context parameter, using a generic view as a base for the controller context when not passed:public ViewRenderer(ControllerContext controllerContext = null) { // Create a known controller from HttpContext if no context is passed if (controllerContext == null) { if (HttpContext.Current != null) controllerContext = CreateController<ErrorController>().ControllerContext; else throw new InvalidOperationException( "ViewRenderer must run in the context of an ASP.NET " + "Application and requires HttpContext.Current to be present."); } Context = controllerContext; }In this case I use the ErrorController class which is a generic controller instance that exists in the same assembly as my ViewRenderer class and that works just fine since ‘generically’ rendered views tend to not rely on anything from the controller other than the model which is explicitly passed.While these days most of my apps use MVC I do still have a number of generic pieces in most of these applications where Razor comes in handy. This includes modules like the above, which when they error often need to display error output. In other cases I need to generate string template output for emailing or logging data to disk. Being able to render simply render an arbitrary View to and pass in a model makes this super nice and easy at least within the context of an ASP.NET application!You can check out the updated ViewRenderer class below to render your ‘generic views’ from anywhere within your ASP.NET applications. Hope some of you find this useful.ResourcesViewRenderer Class in Westwind.Web.Mvc Library (Github)Original ViewRenderer ArticleRazor Hosting Library (GitHub)Original Razor Hosting Article© Rick Strahl, West Wind Technologies, 2005-2013Posted in ASP.NET  MVC   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• JavaScript Intellisense with Telerik in ASP.NET Master Page Project with VS 2010

  - by Otto Neff

  Today I was looking for a solution to get finally the JScript/Javascript/jQuery Intellisense Featureworking with my ASP.Net Webform Project to work. I found some good articles: - JScript IntelliSense Overview- JScript IntelliSense: A Reference for the “Reference” Tag- Enabling JavaScript intellisense in VS.NET 2010 to work with SharePoint 2010- Rich IntelliSense for jQueryBUT, all of suggested solutions did not work right with my Master Page based Visual Studio 2010 Solution.Only with physical Javascript Files (Telerik includes certain Javascript Files like jQuery as Ressource) or/andconfigure always a new ASP.NET Scriptmanager / RadScriptManager on every page derived from the Master Page, wasn't exactly what I was looking for. So I came up with the following simple Solution, to Trick VS2010and still have the Project running with multiple runat="server" Scriptmanagers. In short:- New ASP.NET control derived from ScriptManager with emtpy overwritten OnInit() to use it as emtpy wrapper for VS2010. In detail:New RadScriptManager Classusing System; using System.Collections.Generic; using System.Linq; using System.Web; using Telerik.Web.UI; namespace IntellisenseJavascript.Controls { public class IntelliJS : RadScriptManager { protected override void OnInit(EventArgs e) { } protected override void OnPreRender(EventArgs e) { } protected override void OnLoad(EventArgs e) { } protected override void Render(System.Web.UI.HtmlTextWriter writer) { } public override void RenderControl(System.Web.UI.HtmlTextWriter writer) { } } } web.config<configuration> ... <system.web> ... <pages> <controls> <add tagPrefix="telerik" namespace="Telerik.Web.UI" assembly="Telerik.Web.UI, Version=2011.3.1115.40, Culture=neutral, PublicKeyToken=121fae78165ba3d4"/> <add tagPrefix="VSFix" namespace="IntellisenseJavascript.Controls" assembly="IntellisenseJavascript"/> </controls> </pages> ... Master Page<%@ Master Language="C#" AutoEventWireup="true" CodeBehind="Site.master.cs" Inherits="IntellisenseJavascript.Site" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html > <head id="head" runat="server"> <title></title> <telerik:RadStyleSheetManager ID="radStyleSheetManager" runat="server" /> </head> <body> <form id="form" runat="server"> <telerik:RadScriptManager ID="radScriptManager" runat="server"> <Scripts> <asp:ScriptReference Assembly="Telerik.Web.UI, Version=2011.3.1115.40, Culture=neutral, PublicKeyToken=121fae78165ba3d4" Name="Telerik.Web.UI.Common.Core.js" /> <asp:ScriptReference Assembly="Telerik.Web.UI, Version=2011.3.1115.40, Culture=neutral, PublicKeyToken=121fae78165ba3d4" Name="Telerik.Web.UI.Common.jQuery.js" /> <asp:ScriptReference Assembly="Telerik.Web.UI, Version=2011.3.1115.40, Culture=neutral, PublicKeyToken=121fae78165ba3d4" Name="Telerik.Web.UI.Common.jQueryInclude.js" /> </Scripts> </telerik:RadScriptManager> <telerik:RadAjaxManager ID="radAjaxManager" runat="server"> </telerik:RadAjaxManager> <div> #MASTER CONTENT# <asp:ContentPlaceHolder ID="contentPlaceHolder" runat="server"> </asp:ContentPlaceHolder> </div> </form> <script type="text/javascript"> $(function () { // Masterpage ready $('body').css('margin', '50px'); }); </script> </body> </html> ASPX Page<%@ Page Title="" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="IntellisenseJavascript.Default" %> <asp:Content ID="Content1" ContentPlaceHolderID="contentPlaceHolder" runat="server"> <VSFix:IntelliJS runat="server" ID="intelliJS"> <Scripts> <asp:ScriptReference Assembly="Telerik.Web.UI, Version=2011.3.1115.40, Culture=neutral, PublicKeyToken=121fae78165ba3d4" Name="Telerik.Web.UI.Common.Core.js" /> <asp:ScriptReference Assembly="Telerik.Web.UI, Version=2011.3.1115.40, Culture=neutral, PublicKeyToken=121fae78165ba3d4" Name="Telerik.Web.UI.Common.jQuery.js" /> <asp:ScriptReference Assembly="Telerik.Web.UI, Version=2011.3.1115.40, Culture=neutral, PublicKeyToken=121fae78165ba3d4" Name="Telerik.Web.UI.Common.jQueryInclude.js" /> </Scripts> </VSFix:IntelliJS> <div style="border: 5px solid #FF9900;"> #PAGE CONTENT# </div> <script type="text/javascript"> $(function () { // Page ready $('body').css('border', '5px solid #888'); }); </script> </asp:Content> The Result I know, this is not the way it meant to be... but now at least you can have a Main ScriptManager for all Common Scripts and Settings, inject page specific Javascripts in PageLoad Event in normal ASPX Files and have JavaScript Intellisense for defined Scripts from JS Files or Assembly Ressouce in your Content Maybe, vNext will fix this.

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• Formal Languages, Inductive Proofs &amp; Regular Expressions

  - by MarkPearl

  So I am slogging away at my UNISA stuff. I have just finished doing the initial once non stop read through the first 11 chapters of my COS 201 Textbook - “Introduction to Computer Theory 2nd Edition” by Daniel Cohen. It has been an interesting couple of days, with familiar concepts coming up as well as some new territory. In this posting I am going to cover the first couple of chapters of the book. Let start with Formal Languages… What exactly is a formal language? Pretty much a no duh question for me but still a good one to ask – a formal language is a language that is defined in a precise mathematical way. Does that mean that the English language is a formal language? I would say no – and my main motivation for this is that one can have an English sentence that is correct grammatically that is also ambiguous. For example the ambiguous sentence: "I once shot an elephant in my pyjamas.” For this and possibly many other reasons that I am unaware of, English is termed a “Natural Language”. So why the importance of formal languages in computer science? Again a no duh question in my mind… If we want computers to be effective and useful tools then we need them to be able to evaluate a series of commands in some form of language that when interpreted by the device no confusion will exist as to what we were requesting. Imagine the mayhem that would exist if a computer misinterpreted a command to print a document and instead decided to delete it. So what is a Formal Language made up of… For my study purposes a language is made up of a finite alphabet. For a formal language to exist there needs to be a specification on the language that will describe whether a string of characters has membership in the language or not. There are two basic ways to do this: By a “machine” that will recognize strings of the language (e.g. Finite Automata). By a rule that describes how strings of a language can be formed (e.g. Regular Expressions). When we use the phrase “string of characters”, we can also be referring to a “word”. What is an Inductive Proof? So I am not to far into my textbook and of course it starts referring to proofs and different types. I have had to go through several different approaches of proofs in the past, but I can never remember their formal names , so when I saw “inductive proof” I thought to myself – what the heck is that? Google to the rescue… An inductive proof is like a normal proof but it employs a neat trick which allows you to prove a statement about an arbitrary number n by first proving it is true when n is 1 and then assuming it is true for n=k and showing it is true for n=k+1. The idea is that if you want to show that someone can climb to the nth floor of a fire escape, you need only show that you can climb the ladder up to the fire escape (n=1) and then show that you know how to climb the stairs from any level of the fire escape (n=k) to the next level (n=k+1). Does this sound like a form of recursion? No surprise then that in the same chapter they deal with recursive definitions. An example of a recursive definition for the language EVEN would the 3 rules below: 2 is in EVEN If x is in EVEN then so is x+2 The only elements in the set EVEN are those that be produced by the rules above. Nothing to exciting… So if a definition for a language is done recursively, then it makes sense that the language can be proved using induction. Regular Expressions So I am wondering to myself what use is this all – in fact – I find this the biggest challenge to any university material is that it is quite hard to find the immediate practical applications of some theory in real life stuff. How great was my joy when I suddenly saw the word regular expression being introduced. I had been introduced to regular expressions on Stack Overflow where I was trying to recognize if some text measurement put in by a user was in a valid form or not. For instance, the imperial system of measurement where you have feet and inches can be represented in so many different ways. I had eventually turned to regular expressions as an easy way to check if my parser could correctly parse the text or not and convert it to a normalize measurement. So some rules about languages and regular expressions… Any finite language can be represented by at least one if not more regular expressions A regular expressions is almost a rule syntax for expressing how regular languages can be formed regular expressions are cool For a regular expression to be valid for a language it must be able to generate all the words in the language and no other words. This is important. It doesn’t help me if my regular expression parses 100% of my measurement texts but also lets one or two invalid texts to pass as well. Okay, so this posting jumps around a bit – but introduces some very basic fundamentals for the subject which will be built on in later postings… Time to go and do some practical examples now…

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• Games to Vista Game explorer with Inno Setup

  - by Kraemer

  Ok, i'm trying to force my inno setup installer to add a shortcut of my game to Vista Games Explorer. Theoretically this should do the trick: [Files] Source: "GameuxInstallHelper.dll"; DestDir: "{app}"; Flags: ignoreversion overwritereadonly; [Registry] Root: HKLM; Subkey: SOFTWARE\dir\dir; Flags: uninsdeletekeyifempty Root: HKLM; Subkey: SOFTWARE\dir\dir; ValueName: Path; ValueType: String; ValueData: {app}; Flags: uninsdeletekey Root: HKLM; Subkey: SOFTWARE\dir\dir; ValueName: AppFile; ValueType: String; ValueData:{app}\executable.exe ; Flags: uninsdeletekey [CustomMessages] en.Local=en en.removemsg=Do you wish to remove game saves and settings? en.taskentry=Play [Code] const PlayTask = 0; AllUsers = 2; Current = 3; type TGUID = record Data1: Cardinal; Data2, Data3: Word; Data4: array [0..7] of char; end; var GUID: TGUID; function GetDC(HWND: DWord): DWord; external '[email protected] stdcall'; function GetDeviceCaps(DC: DWord; Index: Integer): Integer; external '[email protected] stdcall'; function ReleaseDC(HWND: DWord;DC: DWord): Integer; external '[email protected] stdcall'; function ShowWindow(hWnd: DWord; nCmdShow: Integer): boolean; external '[email protected] stdcall'; function SetWindowLong(hWnd: DWord; nIndex: Integer; dwNewLong: Longint):Longint; external '[email protected] stdcall'; function GenerateGUID(var GUID: TGUID): Cardinal; external 'GenerateGUID@files:GameuxInstallHelper.dll stdcall setuponly'; function AddToGameExplorer(Binary: String; Path: String; InstallType: Integer; var GUID: TGUID): Cardinal; external 'AddToGameExplorerW@files:GameuxInstallHelper.dll stdcall setuponly'; function CreateTask(InstallType: Integer; var GUID: TGUID; TaskType: Integer; TaskNumber: Integer; TaskName: String; Binary: String; Parameters: String): Cardinal; external 'CreateTaskW@files:GameuxInstallHelper.dll stdcall setuponly'; function RetrieveGUIDForApplication(Binary: String; var GUID: TGUID): Cardinal; external 'RetrieveGUIDForApplicationW@{app}\GameuxInstallHelper.dll stdcall uninstallonly'; function RemoveFromGameExplorer(var GUID: TGUID): Cardinal; external 'RemoveFromGameExplorer@{app}\GameuxInstallHelper.dll stdcall uninstallonly'; function RemoveTasks(var GUID: TGUID): Cardinal; external 'RemoveTasks@{app}\GameuxInstallHelper.dll stdcall uninstallonly'; function InitializeSetup(): Boolean; var appath: string; ResultCode: Integer; begin if RegKeyExists(HKEY_LOCAL_MACHINE, 'SOFTWARE\dir\dir') then begin RegQueryStringValue(HKEY_LOCAL_MACHINE, 'SOFTWARE\dir\dir', 'Path', appath) Exec((appath +'\unins000.exe'), '', '', SW_SHOW, ewWaitUntilTerminated, ResultCode) end else begin Result := TRUE end; end; procedure CurUninstallStepChanged(CurUninstallStep: TUninstallStep); begin if CurUninstallStep = usUninstall then begin if GetWindowsVersion shr 24 > 5 then begin RetrieveGUIDForApplication(ExpandConstant('{app}\AWL_Release.dll'), GUID); RemoveFromGameExplorer(GUID); RemoveTasks(GUID); UnloadDll(ExpandConstant('{app}\GameuxInstallHelper.dll')); end; end; if CurUninstallStep = usPostUninstall then begin if MsgBox(ExpandConstant('{cm:removemsg}'), mbConfirmation, MB_YESNO)=IDYES then begin DelTree(ExpandConstant('{app}'), True, True, True); end; end; end; procedure CurStepChanged(CurStep: TSetupStep); begin if GetWindowsVersion shr 24 > 5 then begin if CurStep = ssInstall then GenerateGUID(GUID); if CurStep = ssPostInstall then begin AddToGameExplorer(ExpandConstant('{app}\AWL_Release.dll'), ExpandConstant('{app}'), Current, GUID); CreateTask(3, GUID, PlayTask, 0, ExpandConstant('{cm:taskentry}'), ExpandConstant('{app}\executable.exe'), ''); CreateTask(3, GUID, 1, 0, 'Game Website', 'http://www.gamewebsite.com/', ''); end; end; end; The installer works just fine, but it doesn't place a shortcut of my game to Games explorer. Since i believe that the problem is on the binary file i guess for that part i should ask for some help. So, can anyone please give me a hand here?

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• SQL Authority News – Play by Play with Pinal Dave – A Birthday Gift

  - by Pinal Dave

  Today is my birthday. Personal Note When I was young, I was always looking forward to my birthday as on this day, I used to get gifts from everybody. Now when I am getting old on each of my birthday, I have almost same feeling but the direction is different. Now on each of my birthday, I feel like giving gifts to everybody. I have received lots of support, love and respect from everybody; and now I must return it back.Well, on this birthday, I have very unique gifts for everybody – my latest course on SQL Server. How I Tune Performance I often get questions where I am asked how do I work on a normal day. I am often asked that how do I work when I have performance tuning project is assigned to me. Lots of people have expressed their desire that they want me to explain and demonstrate my own method of solving performance problem when I am facing real world problem. It is a pretty difficult task as in the real world, nothing goes as planned and usually planned demonstrations have no place there. The real world, demands real solutions and in a timely fashion. If a consultant goes to industry and does not demonstrate his/her capabilities in very first few minutes, it does not matter how much fame he/she is, the door is shown to them eventually. It is true and in my early career, I have faced it quite commonly. I have learned the trick to be honest from the start and request absolutely transparent communication from the organization where I am to consult. Play by Play Play by Play is a very unique setup. It is not planned and it is a step by step course. It is like a reality show – a very real encounter to the problem and real problem solving approach. I had a great time doing this course. Geoffrey Grosenbach (VP of Pluralsight) sits down with me to see what a SQL Server Admin does in the real world. This Play-by-Play focuses on SQL Server performance tuning and I go over optimizing queries and fine-tuning the server. The table of content of this course is very simple. Introduction In the introduction I explained my basic strategies when I am approached by a customer for performance tuning. Basic Information Gathering In this module I explain how I do gather various information for performance tuning project. It is very crucial to demonstrate to customers for consultant his capability of solving problem. I attempt to resolve a small problem which gives a big positive impact on performance, consultant have to gather proper information from the start. I demonstrate in this module, how one can collect all the important performance tuning metrics. Removing Performance Bottleneck In this module, I build upon the previous module’s statistics collected. I analysis various performance tuning measures and immediately start implementing various tweaks on the performance, which will start improving the performance of my server. This is a very effective method and it gives immediate return of efforts. Index Optimization Indexes are considered as a silver bullet for performance tuning. However, it is not true always there are plenty of examples where indexes even performs worst after implemented. The key is to understand a few of the basic properties of the index and implement the right things at the right time. In this module, I describe in detail how to do index optimizations and what are right and wrong with Index. If you are a DBA or developer, and if your application is running slow – this is must attend module for you. I have some really interesting stories to tell as well. Optimize Query with Rewrite Every problem has more than one solution, in this module we will see another very famous, but hard to master skills for performance tuning – Query Rewrite. There are few do’s and don’ts for any query rewrites. I take a very simple example and demonstrate how query rewrite can improve the performance of the query at many folds. I also share some real world funny stories in this module. This course is hosted at Pluralsight. You will need a valid login for Pluralsight to watch  Play by Play: Pinal Dave course. You can also sign up for FREE Trial of Pluralsight to watch this course. As today is my birthday – I will give 10 people (randomly) who will express their desire to learn this course, a free code. Please leave your comment and I will send you free code to watch this course for free. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Training, SQLAuthority News, T SQL, Video

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• JavaScript Intellisense Improvements with VS 2010

  - by ScottGu

  This is the twentieth in a series of blog posts I’m doing on the upcoming VS 2010 and .NET 4 release.  Today’s blog post covers some of the nice improvements coming with JavaScript intellisense with VS 2010 and the free Visual Web Developer 2010 Express.  You’ll find with VS 2010 that JavaScript Intellisense loads much faster for large script files and with large libraries, and that it now provides statement completion support for more advanced scenarios compared to previous versions of Visual Studio. [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] Improved JavaScript Intellisense Providing Intellisense for a dynamic language like JavaScript is more involved than doing so with a statically typed language like VB or C#.  Correctly inferring the shape and structure of variables, methods, etc is pretty much impossible without pseudo-executing the actual code itself – since JavaScript as a language is flexible enough to dynamically modify and morph these things at runtime.  VS 2010’s JavaScript code editor now has the smarts to perform this type of pseudo-code execution as you type – which is how its intellisense completion is kept accurate and complete.  Below is a simple walkthrough that shows off how rich and flexible it is with the final release. Scenario 1: Basic Type Inference When you declare a variable in JavaScript you do not have to declare its type.  Instead, the type of the variable is based on the value assigned to it.  Because VS 2010 pseudo-executes the code within the editor, it can dynamically infer the type of a variable, and provide the appropriate code intellisense based on the value assigned to a variable. For example, notice below how VS 2010 provides statement completion for a string (because we assigned a string to the “foo” variable): If we later assign a numeric value to “foo” the statement completion (after this assignment) automatically changes to provide intellisense for a number: Scenario 2: Intellisense When Manipulating Browser Objects It is pretty common with JavaScript to manipulate the DOM of a page, as well as work against browser objects available on the client.  Previous versions of Visual Studio would provide JavaScript statement completion against the standard browser objects – but didn’t provide much help with more advanced scenarios (like creating dynamic variables and methods).  VS 2010’s pseudo-execution of code within the editor now allows us to provide rich intellisense for a much broader set of scenarios. For example, below we are using the browser’s window object to create a global variable named “bar”.  Notice how we can now get intellisense (with correct type inference for a string) with VS 2010 when we later try and use it: When we assign the “bar” variable as a number (instead of as a string) the VS 2010 intellisense engine correctly infers its type and modifies statement completion appropriately to be that of a number instead: Scenario 3: Showing Off Because VS 2010 is psudo-executing code within the editor, it is able to handle a bunch of scenarios (both practical and wacky) that you throw at it – and is still able to provide accurate type inference and intellisense. For example, below we are using a for-loop and the browser’s window object to dynamically create and name multiple dynamic variables (bar1, bar2, bar3…bar9).  Notice how the editor’s intellisense engine identifies and provides statement completion for them: Because variables added via the browser’s window object are also global variables – they also now show up in the global variable intellisense drop-down as well: Better yet – type inference is still fully supported.  So if we assign a string to a dynamically named variable we will get type inference for a string.  If we assign a number we’ll get type inference for a number.  Just for fun (and to show off!) we could adjust our for-loop to assign a string for even numbered variables (bar2, bar4, bar6, etc) and assign a number for odd numbered variables (bar1, bar3, bar5, etc): Notice above how we get statement completion for a string for the “bar2” variable.  Notice below how for “bar1” we get statement completion for a number:   This isn’t just a cool pet trick While the above example is a bit contrived, the approach of dynamically creating variables, methods and event handlers on the fly is pretty common with many Javascript libraries.  Many of the more popular libraries use these techniques to keep the size of script library downloads as small as possible.  VS 2010’s support for parsing and pseudo-executing libraries that use these techniques ensures that you get better code Intellisense out of the box when programming against them. Summary Visual Studio 2010 (and the free Visual Web Developer 2010 Express) now provide much richer JavaScript intellisense support.  This support works with pretty much all popular JavaScript libraries.  It should help provide a much better development experience when coding client-side JavaScript and enabling AJAX scenarios within your ASP.NET applications. Hope this helps, Scott P.S. You can read my previous blog post on VS 2008’s JavaScript Intellisense to learn more about our previous JavaScript intellisense (and some of the scenarios it supported).  VS 2010 obviously supports all of the scenarios previously enabled with VS 2008.

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• Configuring Expert Search in Communicator 14 and SharePoint 2010

  Communicator 14 provides functionality to be able to search for contacts not just by name, but by skill.  For example a customer service agent at an airline can search for other agents with Travel Advisory experience by typing the search criteria into the Communicator search box and performing a search by keyword.  The search results will return users who have specified that skill in their profile on their SharePoint My Site.  This is actually pretty easy to configure, Ill show you how. Create Search and People Search Results Pages in SharePoint Communicator 14 Expert Search works by using the SharePoint 2010 Search Service to search SharePoint for user profiles with matching keywords.  This requires that you have an Enterprise Search site in your site collection which includes the search service and also the People Results pages.  The easiest way to do this is to create a Search Center site in your site collection. Note: I get an error when trying to create an Enterprise Search site in a Team Site in the SharePoint 2010 RTM bits, so I created it as a site collection that is evident in the URLs you see below. In the screenshots below, you can see that the URL of the SharePoint search service in the Search site collection is http://sps2010/sites/search/_vti_bin/search.asmx, and the URL of the People Search Results page is http://sps2010/sites/Search/Pages/peopleresults.aspx. Point Communications Server 14 to Search and People Search Results Pages For Communicator 14 to be able to perform an Expert Search, you need to configure Communications Server 14 to point to the Search Service and People Search Results page URLs. From a server with the OCS Core bits installed, fire up the Communications Server Management Shell and type Get-CsClientPolicy. Scroll down to the bottom of the output, were interested in setting the values of: SPSearchInternalURL SPSearchExternalURL SPSearchCenterInternalURL SPSearchCenterExternalURL SPSearchInternalURL and SPSearchExternalURL correspond to the internal and external URLs of the SharePoint search service in the Search site collection, while SPSearchCenterInternalURL and SPSearchCenterExternalURL correspond to the internal and external URLs of the people search results pages. Well use the Communications Server Management Shell to set the values of these CS policy properties. For simplicity, Im only going to set the internal URLs here. Set-CsClientPolicy SPSearchInternalURL http://sps2010/sites/search/_vti_bin/search.asmx     -SPSearchCenterInternalURL http://sps2010/sites/Search/Pages/peopleresults.aspx Log out and back into Communicator.  You can verify that these settings were applied by running the Get-CsClientPolicy cmdlet again from the Communications Server Management Shell. However, theres another super-secret ninja trick to verify that the settings were applied: Find the Communicator icon in the Windows System Tray Hold down the Ctrl button Click (left) the Communicator icon in the Windows System Tray do not depress the Ctrl button You should now see an extra menu item called Configuration Information, click it. Scroll down and locate the Expert Search URL and SharePoint Search Center URL keys and verify that their values correspond to those you set using the Set-CsClientPolicy PowerShell cmdlet. Configure a Sharepoint User Profile Import Im not going to provide detailed steps here except to say that you need to configure the SharePoint 2010 User Profile  Service Application to import user account details from Active Directory on a scheduled basis. This is a critical step because there are several user profile properties e.g. SipAddress that are only populated by a user profile import.  When performing an Expert Search, Communicator can only render results for users who have a SipAddress specified. Add Skills to User Profiles Navigate to your My Site and click on My Profile.  This page allows you to set many contact details that are searchable in SharePoint.  Were particularly interested in the Ask Me About property of a users profile.  Expert Search searches against this property to find users with matching skills. Configure a SharePoint Search Crawl Ensure that you have a scheduled job to crawl your Local SharePoint Sites content source.  Depending on how you have this configured, it will also crawl the My Site site collection and add user properties such as Ask Me About to the search index. Thats It! SharePoint 2010 provides new social and collaboration features to help users find other users with similar skills or interests. Expert Search extends this functionality directly into Microsoft Communicator 14, allowing you to interact with the users directly from the search results. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Recovering from apt-get upgrade gone wrong due to a full disk

  - by Peter

  I was performing an apt-get upgrade on an Ubuntu 12.04.5 LTS box that hadn't been updated in a little while and the upgrade failed due to 'No space left on device'. After a little while I worked out space meant inodes and I have freed some up but unfortunately things have been left something askew. I have tried manually installing the old versions of packages mentioned using dpkg -i but that doesn't help. I have tried apt-get upgrade and apt-get -f install to no avail. Results are below. Any ideas how to fix things up? FIXED: Installing the earlier versions again manually via dpkg -i and then apt-get -f install has done the trick. Not sure why this didn't work the first time. The packages in question are listed below but they will presumably vary. libssl1.0.0_1.0.1-4ubuntu5.14_i386.deb linux-headers-3.2.0-64-generic-pae_3.2.0-64.97_i386.deb linux-image-generic-pae_3.2.0.64.76_i386.deb linux-headers-3.2.0-64_3.2.0-64.97_all.deb linux-headers-generic-pae_3.2.0.64.76_i386.deb root@unlinked:/tmp# apt-get upgrade Reading package lists... Done Building dependency tree Reading state information... Done You might want to run ‘apt-get -f install’ to correct these. The following packages have unmet dependencies. libssl-dev : Depends: libssl1.0.0 (= 1.0.1-4ubuntu5.14) but 1.0.1-4ubuntu5.17 is installed linux-generic-pae : Depends: linux-image-generic-pae (= 3.2.0.64.76) but 3.2.0.67.79 is installed Depends: linux-headers-generic-pae (= 3.2.0.64.76) but 3.2.0.67.79 is installed E: Unmet dependencies. Try using -f. root@unlinked:/tmp# apt-get -f install Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following packages were automatically installed and are no longer required: linux-headers-3.2.0-43-generic-pae linux-headers-3.2.0-38-generic-pae linux-headers-3.2.0-41-generic-pae linux-headers-3.2.0-36-generic-pae linux-headers-3.2.0-63-generic-pae linux-headers-3.2.0-58-generic-pae linux-headers-3.2.0-60-generic-pae linux-headers-3.2.0-55-generic-pae linux-headers-3.2.0-40 linux-headers-3.2.0-41 linux-headers-3.2.0-36 linux-headers-3.2.0-37 linux-headers-3.2.0-43 linux-headers-3.2.0-38 linux-headers-3.2.0-44 linux-headers-3.2.0-39 linux-headers-3.2.0-45 linux-headers-3.2.0-51 linux-headers-3.2.0-52 linux-headers-3.2.0-53 linux-headers-3.2.0-48 linux-headers-3.2.0-54 linux-headers-3.2.0-60 linux-headers-3.2.0-55 linux-headers-3.2.0-61 linux-headers-3.2.0-56 linux-headers-3.2.0-57 linux-headers-3.2.0-63 linux-headers-3.2.0-58 linux-headers-3.2.0-59 linux-headers-3.2.0-52-generic-pae linux-headers-3.2.0-44-generic-pae linux-headers-3.2.0-39-generic-pae linux-headers-3.2.0-37-generic-pae linux-headers-3.2.0-59-generic-pae linux-headers-3.2.0-61-generic-pae linux-headers-3.2.0-56-generic-pae linux-headers-3.2.0-53-generic-pae linux-headers-3.2.0-48-generic-pae linux-headers-3.2.0-45-generic-pae linux-headers-3.2.0-40-generic-pae linux-headers-3.2.0-57-generic-pae linux-headers-3.2.0-54-generic-pae linux-headers-3.2.0-51-generic-pae Use 'apt-get autoremove' to remove them. The following extra packages will be installed: libssl-dev linux-generic-pae The following packages will be upgraded: libssl-dev linux-generic-pae 2 to upgrade, 0 to newly install, 0 to remove and 0 not to upgrade. 2 not fully installed or removed. Need to get 0 B/1,427 kB of archives. After this operation, 1,024 B of additional disk space will be used. Do you want to continue [Y/n]? y dpkg: dependency problems prevent configuration of libssl-dev: libssl-dev depends on libssl1.0.0 (= 1.0.1-4ubuntu5.14); however: Version of libssl1.0.0 on system is 1.0.1-4ubuntu5.17. dpkg: error processing libssl-dev (--configure): dependency problems - leaving unconfigured No apport report written because the error message indicates it's a follow-up error from a previous failure. dpkg: dependency problems prevent configuration of linux-generic-pae: linux-generic-pae depends on linux-image-generic-pae (= 3.2.0.64.76); however: Version of linux-image-generic-pae on system is 3.2.0.67.79. linux-generic-pae depends on linux-headers-generic-pae (= 3.2.0.64.76); however: Version of linux-headers-generic-pae on system is 3.2.0.67.79. dpkg: error processing linux-generic-pae (--configure): dependency problems - leaving unconfigured No apport report written because the error message indicates it's a follow-up error from a previous failure. Errors were encountered while processing: libssl-dev linux-generic-pae E: Sub-process /usr/bin/dpkg returned an error code (1)

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• Analysing and measuring the performance of a .NET application (survey results)

  - by Laila

  Back in December last year, I asked myself: could it be that .NET developers think that you need three days and a PhD to do performance profiling on their code? What if developers are shunning profilers because they perceive them as too complex to use? If so, then what method do they use to measure and analyse the performance of their .NET applications? Do they even care about performance? So, a few weeks ago, I decided to get a 1-minute survey up and running in the hopes that some good, hard data would clear the matter up once and for all. I posted the survey on Simple Talk and got help from a few people to promote it. The survey consisted of 3 simple questions: Amazingly, 533 developers took the time to respond - which means I had enough data to get representative results! So before I go any further, I would like to thank all of you who contributed, because I now have some pretty good answers to the troubling questions I was asking myself. To thank you properly, I thought I would share some of the results with you. First of all, application performance is indeed important to most of you. In fact, performance is an intrinsic part of the development cycle for a good 40% of you, which is much higher than I had anticipated, I have to admit. (I know, "Have a little faith Laila!") When asked what tool you use to measure and analyse application performance, I found that nearly half of the respondents use logging statements, a third use performance counters, and 70% of respondents use a profiler of some sort (a 3rd party performance profilers, the CLR profiler or the Visual Studio profiler). The importance attributed to logging statements did surprise me a little. I am still not sure why somebody would go to the trouble of manually instrumenting code in order to measure its performance, instead of just using a profiler. I personally find the process of annotating code, calculating times from log files, and relating it all back to your source terrifyingly laborious. Not to mention that you then need to remember to turn it all off later! Even when you have logging in place throughout all your code anyway, you still have a fair amount of potentially error-prone calculation to sift through the results; in addition, you'll only get method-level rather than line-level timings, and you won't get timings from any framework or library methods you don't have source for. To top it all, we all know that bottlenecks are rarely where you would expect them to be, so you could be wasting time looking for a performance problem in the wrong place. On the other hand, profilers do all the work for you: they automatically collect the CPU and wall-clock timings, and present the results from method timing all the way down to individual lines of code. Maybe I'm missing a trick. I would love to know about the types of scenarios where you actively prefer to use logging statements. Finally, while a third of the respondents didn't have a strong opinion about code performance profilers, those who had an opinion thought that they were mainly complex to use and time consuming. Three respondents in particular summarised this perfectly: "sometimes, they are rather complex to use, adding an additional time-sink to the process of trying to resolve the existing problem". "they are simple to use, but the results are hard to understand" "Complex to find the more advanced things, easy to find some low hanging fruit". These results confirmed my suspicions: Profilers are seen to be designed for more advanced users who can use them effectively and make sense of the results. I found yet more interesting information when I started comparing samples of "developers for whom performance is an important part of the dev cycle", with those "to whom performance is only looked at in times of crisis", and "developers to whom performance is not important, as long as the app works". See the three graphs below. Sample of developers to whom performance is an important part of the dev cycle: Sample of developers to whom performance is important only in times of crisis: Sample of developers to whom performance is not important, as long as the app works: As you can see, there is a strong correlation between the usage of a profiler and the importance attributed to performance: indeed, the more important performance is to a development team, the more likely they are to use a profiler. In addition, developers to whom performance is an important part of the dev cycle have a higher tendency to use a much wider range of methods for performance measurement and analysis. And, unsurprisingly, the less important performance is, the less varied the methods of measurement are. So all in all, to come back to my random questions: .NET developers do care about performance. Those who care the most use a wider range of performance measurement methods than those who care less. But overall, logging statements, performance counters and third party performance profilers are the performance measurement methods of choice for most developers. Finally, although most of you find code profilers complex to use, those of you who care the most about performance tend to use profilers more than those of you to whom performance is not so important.

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• MVVM Light V4 preview 2 (BL0015) #mvvmlight

  - by Laurent Bugnion

  Over the past few weeks, I have worked hard on a few new features for MVVM Light V4. Here is a second early preview (consider this pre-alpha if you wish). The features are unit-tested, but I am now looking for feedback and there might be bugs! Bug correction: Messenger.CleanupList is now thread safe This was an annoying bug that is now corrected: In some circumstances, an exception could be thrown when the Messenger’s recipients list was cleaned up (i.e. the “dead” instances were removed). The method is called now and then and the exception was thrown apparently at random. In fact it was really a multi-threading issue, which is now corrected. Bug correction: AllowPartiallyTrustedCallers prevents EventToCommand to work This is a particularly annoying regression bug that was introduced in BL0014. In order to allow MVVM Light to work in XBAPs too, I added the AllowPartiallyTrustedCallers attribute to the assemblies. However, we just found out that this causes issues when using EventToCommand. In order to allow EventToCommand to continue working, I reverted to the previous state by removing the AllowPartiallyTrustedCallers attribute for now. I will work with my friends at Microsoft to try and find a solution. Stay tuned. Bug correction: XML documentation file is now generated in Release configuration The XML documentation file was not generated for the Release configuration. This was a simple flag in the project file that I had forgotten to set. This is corrected now. Applying EventToCommand to non-FrameworkElements This feature has been requested in order to be able to execute a command when a Storyboard is completed. I implemented this, but unfortunately found out that EventToCommand can only be added to Storyboards in Silverlight 3 and Silverlight 4, but not in WPF or in Windows Phone 7. This obviously limits the usefulness of this change, but I decided to publish it anyway, because it is pretty damn useful in Silverlight… Why not in WPF? In WPF, Storyboards added to a resource dictionary are frozen. This is a feature of WPF which allows to optimize certain objects for performance: By freezing them, it is a contract where we say “this object will not be modified anymore, so do your perf optimization on them without worrying too much”. Unfortunately, adding a Trigger (such as EventTrigger) to an object in resources does not work if this object is frozen… and unfortunately, there is no way to tell WPF not to freeze the Storyboard in the resources… so there is no way around that (at least none I can see. In Silverlight, objects are not frozen, so an EventTrigger can be added without problems. Why not in WP7? In Windows Phone 7, there is a totally different issue: Adding a Trigger can only be done to a FrameworkElement, which Storyboard is not. Here I think that we might see a change in a future version of the framework, so maybe this small trick will work in the future. Workaround? Since you cannot use the EventToCommand on a Storyboard in WPF and in WP7, the workaround is pretty obvious: Handle the Completed event in the code behind, and call the Command from there on the ViewModel. This object can be obtained by casting the DataContext to the ViewModel type. This means that the View needs to know about the ViewModel, but I never had issues with that anyway. New class: NotifyPropertyChanged Sometimes when you implement a model object (for example Customer), you would like to have it implement INotifyPropertyChanged, but without having all the frills of a ViewModelBase. A new class named NotifyPropertyChanged allows you to do that. This class is a simple implementation of INotifyPropertyChaned (with all the overloads of RaisePropertyChanged that were implemented in BL0014). In fact, ViewModelBase inherits NotifyPropertyChanged. ViewModelBase does not implement IDisposable anymore The IDisposable interface and the Dispose method had been marked obsolete in the ViewModelBase class already in V3. Now they have been removed. Note: By this, I do not mean that IDisposable is a bad interface, or that it shouldn’t be used on viewmodels. In the contrary, I know that this interface is very useful in certain circumstances. However, I think that having it by default on every instance of ViewModelBase was sending a wrong message. This interface has a strong meaning in .NET: After Dispose has been executed, the instance should not be used anymore, and should be ready for garbage collection. What I really wanted to have on ViewModelBase was rather a simple cleanup method, something that can be executed now and then during runtime. This is fulfilled by the ICleanup interface and its Cleanup method. If your ViewModels need IDisposable, you can still use it! You will just have to implement the interface on the class itself, because it is not available on ViewModelBase anymore. What’s next? I have a couple exciting new features implemented already but that need more testing before they go live… Just stay tuned and by MIX11 (12-14 April 2011), we should see at least a major addition to MVVM Light Toolkit, as well as another smaller feature which is pretty cool nonetheless More about this later! Happy Coding Laurent   Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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• Advanced donut caching: using dynamically loaded controls

  - by DigiMortal

  Yesterday I solved one caching problem with local community portal. I enabled output cache on SharePoint Server 2007 to make site faster. Although caching works fine I needed to do some additional work because there are some controls that show different content to different users. In this example I will show you how to use “donut caching” with user controls – powerful way to drive some content around cache. About donut caching Donut caching means that although you are caching your content you have some holes in it so you can still affect the output that goes to user. By example you can cache front page on your site and still show welcome message that contains correct user name. To get better idea about donut caching I suggest you to read ScottGu posting Tip/Trick: Implement "Donut Caching" with the ASP.NET 2.0 Output Cache Substitution Feature. Basically donut caching uses ASP.NET substitution control. In output this control is replaced by string you return from static method bound to substitution control. Again, take a look at ScottGu blog posting I referred above. Problem If you look at Scott’s example it is pretty plain and easy by its output. All it does is it writes out current user name as string. Here are examples of my login area for anonymous and authenticated users:    It is clear that outputting mark-up for these views as string is pretty lame to implement in code at string level. Every little change in design will end up with new version of controls library because some parts of design “live” there. Solution: using user controls I worked out easy solution to my problem. I used cache substitution and user controls together. I have three user controls: LogInControl – this is the proxy control that checks which “real” control to load. AnonymousLogInControl – template and logic for anonymous users login area. AuthenticatedLogInControl – template and logic for authenticated users login area. This is the control we render for each user separately because it contains user name and user profile fill percent. Anonymous control is not very interesting because it is only about keeping mark-up in separate file. Interesting parts are LogInControl and AuthenticatedLogInControl. Creating proxy control The first thing was to create control that has substitution area where “real” control is loaded. This proxy control should also be available to decide which control to load. The definition of control is very primitive. <%@ Control EnableViewState="false" Inherits="MyPortal.Profiles.LogInControl" %> <asp:Substitution runat="server" MethodName="ShowLogInBox" /> But code is a little bit tricky. Based on current user instance we decide which login control to load. Then we create page instance and load our control through it. When control is loaded we will call DataBind() method. In this method we evaluate all fields in loaded control (it was best choice as Load and other events will not be fired). Take a look at the code. public static string ShowLogInBox(HttpContext context) {     var user = SPContext.Current.Web.CurrentUser;     string controlName;       if (user != null)         controlName = "AuthenticatedLogInControl.ascx";     else         controlName = "AnonymousLogInControl.ascx";       var path = "~/_controltemplates/" + controlName;     var output = new StringBuilder(10000);       using(var page = new Page())     using(var ctl = page.LoadControl(path))     using(var writer = new StringWriter(output))     using(var htmlWriter = new HtmlTextWriter(writer))     {         ctl.DataBind();         ctl.RenderControl(htmlWriter);     }     return output.ToString(); } When control is bound to data we ask to render it its contents to StringBuilder. Now we have the output of control as string and we can return it from our method. Of course, notice how correct I am with resources disposing. :) The method that returns contents for substitution control is static method that has no connection with control instance because hen page is read from cache there are no instances of controls available. Conclusion As you saw it was not very hard to use donut caching with user controls. Instead of writing mark-up of controls to static method that is bound to substitution control we can still use our user controls.

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• Getting to grips with the stack in nasm

  - by MarkPearl

  Today I spent a good part of my day getting to grips with the stack and nasm. After looking at my notes on nasm I think this is one area for the course I am doing they could focus more on… So here are some snippets I have put together that have helped me understand a little bit about the stack… Simplest example of the stack You will probably see examples like the following in circulation… these demonstrate the simplest use of the stack… org 0x100 bits 16 jmp main main: push 42h push 43h push 44h mov ah,2h ;set to display characters pop dx    ;get the first value int 21h   ;and display it pop dx    ;get 2nd value int 21h   ;and display it pop dx    ;get 3rd value int 21h   ;and display it int 20h The output from above code would be… DCB Decoupling code using “call” and “ret” This is great, but it oversimplifies what I want to use the stack for… I do not know if this goes against the grain of assembly programmers or not, but I want to write loosely coupled assembly code – and I want to use the stack as a mechanism for passing values into my decoupled code. In nasm we have the call and return instructions, which provides a mechanism for decoupling code, for example the following could be done… org 0x100 bits 16 jmp main ;---------------------------------------- displayChar: mov ah,2h mov dx,41h int 21h ret ;---------------------------------------- main: call displayChar int 20h   This would output the following to the console A So, it would seem that call and ret allow us to jump to segments of our code and then return back to the calling position – a form of segmenting the code into what we would called in higher order languages “functions” or “methods”. The only issue is, in higher order languages there is a way to pass parameters into the functions and return results. Because of the primitive nature of the call and ret instructions, this does not seem to be obvious. We could of course use the registers to pass values into the subroutine and set values coming out, but the problem with this is we… Have a limited number of registers Are threading our code with tight coupling (it would be hard to migrate methods outside of their intended use in a particular program to another one) With that in mind, I turn to the stack to provide a loosely coupled way of calling subroutines… First attempt with the Stack Initially I thought this would be simple… we could use code that looks as follows to achieve what I want… org 0x100 bits 16 jmp main ;---------------------------------------- displayChar: mov ah,2h pop dx int 21h ret ;---------------------------------------- main: push 41h call displayChar int 20h   However running this application does not give the desired result, I want an ‘A’ to be returned, and I am getting something totally different (you will to). Reading up on the call and ret instructions a discovery is made… they are pushing and popping things onto and off the stack as well… When the call instruction is executed, the current value of IP (the address of the instruction to follow) is pushed onto the stack, when ret is called, the last value on the stack is popped off into the IP register. In effect what the above code is doing is as follows with the stack… push 41h push current value of ip pop current value of ip to dx pop 41h to ip This is not what I want, I need to access the 41h that I pushed onto the stack, but the call value (which is necessary) is putting something in my way. So, what to do? Remember we have other registers we can use as well as a thing called indirect addressing… So, after some reading around, I came up with the following approach using indirect addressing… org 0x100 bits 16 jmp main ;---------------------------------------- displayChar: mov bp,sp mov ah,2h mov dx,[bp+2] int 21h ret ;---------------------------------------- main: push 41h call displayChar int 20h In essence, what I have done here is used a trick with the stack pointer… it goes as follows… Push 41 onto the stack Make the call to the function, which will push the IP register onto the stack and then jump to the displayChar label Move the value in the stack point to the bp register (sp currently points at IP register) Move the at the location of bp minus 2 bytes to dx (this is now the value 41h) display it, execute the ret instruction, which pops the ip value off the stack and goes back to the calling point This approach is still very raw, some further reading around shows that I should be pushing the value of bp onto the stack before replacing it with sp, but it is the starting thread to getting loosely coupled subroutines. Let’s see if you get what the following output would be? org 0x100 bits 16 jmp main ;---------------------------------------- displayChar: mov bp,sp mov ah,2h mov dx,[bp+4] int 21h mov dx,[bp+2] int 21h ret ;---------------------------------------- main: push 41h push 42h call displayChar int 20h The output is… AB Where to from here? If by any luck some assembly programmer comes along and see this code and notices that I have made some fundamental flaw in my logic… I would like to know, so please leave a comment… appreciate any feedback!

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• Forcing an External Activation with Service Broker

  - by Davide Mauri

  In these last days I’ve been working quite a lot with Service Broker, a technology I’m really happy to work with, since it can give a lot of satisfaction. The scale-out solution one can easily build is simply astonishing. I’m helping a company to build a very scalable and – yet almost inexpensive – invoicing system that has to be able to scale out using commodity hardware. To offload the work from the main server to satellite “compute nodes” (yes, I’ve borrowed this term from PDW) we’re using Service Broker and the External Activator application available in the SQL Server Feature Pack. For those who are not used to work with SSB, the External Activation is a feature that allows you to intercept the arrival of a message in a queue right from your application code. http://msdn.microsoft.com/en-us/library/ms171617.aspx (Look for “Event-Based Activation”) In order to make life even more easier, Microsoft released the External Activation application that saves you even from writing even this code. http://blogs.msdn.com/b/sql_service_broker/archive/tags/external+activator/ The External Activator application can be configured to execute your own application so that each time a message – an invoice in my case – arrives in the target queue, the invoking application is executed and the invoice is calculated. The very nice feature of External Activator is that it can automatically execute as many configured application in order to process as many messages as your system can handle.  This also a lot of create a scale-out solution, leaving to the developer only a fraction of the problems that usually came with asynchronous programming. Developers are also shielded from Service Broker since everything can be encapsulated in Stored Procedures, so that – for them – developing such scale-out asynchronous solution is not much more complex than just executing a bunch of Stored Procedures. Now, if everything works correctly, you don’t have to bother of anything else. You put messages in the queue and your application, invoked by the External Activator, process them. But what happen if for some reason your application fails to process the messages. For examples, it crashes? The message is safe in the queue so you just need to process it again. But your application is invoked by the External Activator application, so now the question is, how do you wake up that app? Service Broker will engage the activation process only if certain conditions are met: http://msdn.microsoft.com/en-us/library/ms171601.aspx But how we can invoke the activation process manually, without having to wait for another message to arrive (the arrival of a new message is a condition that can fire the activation process)? The “trick” is to do manually with the activation process does: sending a system message to a queue in charge of handling External Activation messages: declare @conversationHandle uniqueidentifier; declare @n xml = N' <EVENT_INSTANCE>   <EventType>QUEUE_ACTIVATION</EventType>   <PostTime>' + CONVERT(CHAR(24),GETDATE(),126) + '</PostTime>   <SPID>' + CAST(@@SPID AS VARCHAR(9)) + '</SPID>   <ServerName>[your_server_name]</ServerName>   <LoginName>[your_login_name]</LoginName>   <UserName>[your_user_name]</UserName>   <DatabaseName>[your_database_name]</DatabaseName>   <SchemaName>[your_queue_schema_name]</SchemaName>   <ObjectName>[your_queue_name]</ObjectName>   <ObjectType>QUEUE</ObjectType> </EVENT_INSTANCE>' begin dialog conversation     @conversationHandle from service        [<your_initiator_service_name>] to service          '<your_event_notification_service>' on contract         [http://schemas.microsoft.com/SQL/Notifications/PostEventNotification] with     encryption = off,     lifetime = 6000 ; send on conversation     @conversationHandle message type     [http://schemas.microsoft.com/SQL/Notifications/EventNotification] (@n) ;     end conversation @conversationHandle; That’s it! Put the code in a Stored Procedure and you can add to your application a button that says “Force Queue Processing” (or something similar) in order to start the activation process whenever you need it (which should not occur too frequently but it may happen). PS I know that the “fire-and-forget” (ending the conversation without waiting for an answer) technique is not a best practice, but in this case I don’t see how it can hurts so I decided to stay very close to the KISS principle []

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• Autoscaling in a modern world&hellip;. Part 2

  - by Steve Loethen

  When we last left off, we had a web application spinning away in the cloud, and a local console application watching it and reacting to changes in demand.  Reactions that were specified by a set of rules.  Let’s talk about those rules. Constraints.  The first set of rules this application answered to were the constraints. Here is what they looked like: <constraintRules> <rule name="default" enabled="true" rank="1" description="The default constraint rule"> <actions> <range min="1" max="4" target="AutoscalingApplicationRole"/> </actions> </rule> </constraintRules> Pretty basic.  We have one role, the “AutoscalingApplicationRole”, and we have decided to have it live within a range of 1 to 4.  This rule does not adjust, but instead, set’s limits on what other rules can do.  It has a rank, so you can have you can specify other sets of constraints, perhaps based on time or date, to allow for deviations from this set.  But for now, let’s keep it simple.  In the real world, you would probably use the minimum to set a lower end SLA.  A common value might be a 2, to prevent the reactive rules from ever taking you down to 1 role.  The maximum is often used to keep a rule from driving the cost up, setting an upper limit to prevent you waking up one morning and find a bill for hundreds of instances you didn’t expect.  So, here we have the range we want our application to live inside.  This is good for our investigation and testing.  Next, let’s take a look at the reactive rules.  These rules are what you use to react (hence reactive rules) to changing demands on your application.  The HOL has two simple rules.  One that looks at a queue depth, and one that looks at a performance counter that reports cpu utilization.  the XML in the rules file looks like this: <reactiveRules> <rule name="ScaleUp" rank="10" description="Scale Up the web role" enabled="true"> <when> <any> <greaterOrEqual operand="Length_05_holqueue" than="10"/> <greaterOrEqual operand="CPU_05_holwebrole" than="65"/> </any> </when> <actions> <scale target="AutoscalingApplicationRole" by="1"/> </actions> </rule> <rule name="ScaleDown" rank="10" description="Scale down the web role" enabled="true"> <when> <all> <less operand="Length_05_holqueue" than="5"/> <less operand="CPU_05_holwebrole" than="40"/> </all> </when> <actions> <scale target="AutoscalingApplicationRole" by="-1"/> </actions> </rule> </reactiveRules> <operands> <performanceCounter alias="CPU_05_holwebrole" performanceCounterName="\Processor(_Total)\% Processor Time" source="AutoscalingApplicationRole" timespan="00:05:00" aggregate="Average" /> <queueLength alias="Length_05_holqueue" queue="hol-queue" timespan="00:05:00" aggregate="Average"/> </operands> These rules are currently contained in a file called rules.xml, that is in the root of the console application.  The console app, starts up, grabs the rules and starts watching the 2 operands.  When it detects a rule has been satisfied, it performs the desired action.  (here, scale up or down my 1). But I want to host the autoscaler  in the cloud.  For my first trick, I will move the rules (and another file called services.xml) to azure blob storage.  Look for part 3.

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• Goodbye XML&hellip; Hello YAML (part 2)

  - by Brian Genisio's House Of Bilz

  Part 1 After I explained my motivation for using YAML instead of XML for my data, I got a lot of people asking me what type of tooling is available in the .Net space for consuming YAML.  In this post, I will discuss a nice tooling option as well as describe some small modifications to leverage the extremely powerful dynamic capabilities of C# 4.0.  I will be referring to the following YAML file throughout this post Recipe: Title: Macaroni and Cheese Description: My favorite comfort food. Author: Brian Genisio TimeToPrepare: 30 Minutes Ingredients: - Name: Cheese Quantity: 3 Units: cups - Name: Macaroni Quantity: 16 Units: oz Steps: - Number: 1 Description: Cook the macaroni - Number: 2 Description: Melt the cheese - Number: 3 Description: Mix the cooked macaroni with the melted cheese Tooling It turns out that there are several implementations of YAML tools out there.  The neatest one, in my opinion, is YAML for .NET, Visual Studio and Powershell.  It includes a great editor plug-in for Visual Studio as well as YamlCore, which is a parsing engine for .Net.  It is in active development still, but it is certainly enough to get you going with YAML in .Net.  Start by referenceing YamlCore.dll, load your document, and you are on your way.  Here is an example of using the parser to get the title of the Recipe: var yaml = YamlLanguage.FileTo("Data.yaml") as Hashtable; var recipe = yaml["Recipe"] as Hashtable; var title = recipe["Title"] as string; In a similar way, you can access data in the Ingredients set: var yaml = YamlLanguage.FileTo("Data.yaml") as Hashtable; var recipe = yaml["Recipe"] as Hashtable; var ingredients = recipe["Ingredients"] as ArrayList; foreach (Hashtable ingredient in ingredients) { var name = ingredient["Name"] as string; } You may have noticed that YamlCore uses non-generic Hashtables and ArrayLists.  This is because YamlCore was designed to work in all .Net versions, including 1.0.  Everything in the parsed tree is one of two things: Hashtable, ArrayList or Value type (usually String).  This translates well to the YAML structure where everything is either a Map, a Set or a Value.  Taking it further Personally, I really dislike writing code like this.  Years ago, I promised myself to never write the words Hashtable or ArrayList in my .Net code again.  They are ugly, mostly depreciated collections that existed before we got generics in C# 2.0.  Now, especially that we have dynamic capabilities in C# 4.0, we can do a lot better than this.  With a relatively small amount of code, you can wrap the Hashtables and Array lists with a dynamic wrapper (wrapper code at the bottom of this post).  The same code can be re-written to look like this: dynamic doc = YamlDoc.Load("Data.yaml"); var title = doc.Recipe.Title; And dynamic doc = YamlDoc.Load("Data.yaml"); foreach (dynamic ingredient in doc.Recipe.Ingredients) { var name = ingredient.Name; } I significantly prefer this code over the previous.  That’s not all… the magic really happens when we take this concept into WPF.  With a single line of code, you can bind to the data dynamically in the view: DataContext = YamlDoc.Load("Data.yaml"); Then, your XAML is extremely straight-forward (Nothing else.  No static types, no adapter code.  Nothing): <StackPanel> <TextBlock Text="{Binding Recipe.Title}" /> <TextBlock Text="{Binding Recipe.Description}" /> <TextBlock Text="{Binding Recipe.Author}" /> <TextBlock Text="{Binding Recipe.TimeToPrepare}" /> <TextBlock Text="Ingredients:" FontWeight="Bold" /> <ItemsControl ItemsSource="{Binding Recipe.Ingredients}" Margin="10,0,0,0"> <ItemsControl.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <TextBlock Text="{Binding Quantity}" /> <TextBlock Text=" " /> <TextBlock Text="{Binding Units}" /> <TextBlock Text=" of " /> <TextBlock Text="{Binding Name}" /> </StackPanel> </DataTemplate> </ItemsControl.ItemTemplate> </ItemsControl> <TextBlock Text="Steps:" FontWeight="Bold" /> <ItemsControl ItemsSource="{Binding Recipe.Steps}" Margin="10,0,0,0"> <ItemsControl.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <TextBlock Text="{Binding Number}" /> <TextBlock Text=": " /> <TextBlock Text="{Binding Description}" /> </StackPanel> </DataTemplate> </ItemsControl.ItemTemplate> </ItemsControl> </StackPanel> This nifty XAML binding trick only works in WPF, unfortunately.  Silverlight handles binding differently, so they don’t support binding to dynamic objects as of late (March 2010).  This, in my opinion, is a major lacking feature in Silverlight and I really hope we will see this feature available to us in Silverlight 4 Release.  (I am not very optimistic for Silverlight 4, but I can hope for the feature in Silverlight 5, can’t I?) Conclusion I still have a few things I want to say about using YAML in the .Net space including de-serialization and using IronRuby for your YAML parser, but this post is hopefully enough to see how easy it is to incorporate YAML documents in your code. Codeplex Site for YAML tools Dynamic wrapper for YamlCore

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