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  • ASP.NET: With C# or C# + VB.NET?

    - by Sahat
    I am currently reading Beginning ASP.NET 4: in C# and VB (Wrox Programmer to Programmer) and it comes with both C# and VB.NET source code. I am definitely planning to use C# in the future for most of my projects. But VB.NET - is it really worth learning side-by-side with C#? Are there such cases when VB.NET is preferred over C#?

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  • ASP.NET with C# or VB.NET + C#?

    - by Sahat
    I am currently reading Beginning ASP.NET 4: in C# and VB (Wrox Programmer to Programmer) and it comes with both C# and VB.NET source code. I am definitely planning to use C# in the future for most of my projects. But VB.NET - is it worth learning side-by-side with C#? Will there be a case when VB.NET is preferred over C#?

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  • Stop chkdsk when Windows 7 on one drive and Windows 8 on another

    - by markmnl
    I installed Windows 8 (retail) on a new drive with my Windows 7 drive unplugged. So each Windows has no idea about the other one and I use the BIOS boot options to select which drive hence OS to boot into. Now whenever I boot into Windows 8 then boot into Windows 7, Windows 7 runs chkdisk presumably because Windows 8 messed with it. Is there anyway to stop this? (In hindsight I should have installed Windows 8 with Windows 7 drive plugged in so I could use the Windows dual boot options).

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  • Windows service running as network service - how does it authenticate? Breaking change in W2K8?

    - by Max
    A Windows service running as "Network Service" talks to services on other machines (here: SQL Server and Analysis Services), using Windows authentication. For authentication, we have to grant permissions to the machine account of the service. E.g. if service runs on server MYSERVER in domain MYDOMAIN, it'll authenticate itself as "MYDOMAIN\MYSERVER$". - Am I correct, so far? Now here's my question: does this still apply when talking to a service on the SAME machine? Or will it authenticate with something like "NT AUTHORITY\Network Service" instead when connecting to a local service? And: is there any chance this is a breaking change from Windows 2003 to Windows 2008? We're having an actual issue in our system where the account was able to connect to local services with only the machine account having permissions in W2K3. In W2K8, this doesn't seem to work anymore: authentication to local services now fails, but still works to remote machines.

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  • Installed Windows 8 Upgrade AFTER Formatting HD - any way to activate?

    - by Brandon Vogel
    I had an XP system - formatted the HD then ran Windows 8 Upgrade install. Install was fine. It cannot activate and gives me the 'this is an upgrade' error. Is there ANY way to fix this (MS Support call or something?) before I scrap the entire Windows 8 install, Reinstall XP, then upgrade to Windows 8 the proper way? I hate to waste the day's worth of config-the-new-os time if not absolutely necessary. Error was the 0XC004F061 from Windows 8.

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  • How do I fix a corrupted copy of .Net Framework on Windows 7?

    - by David
    I receive the following error when trying to run applications that require .net Framework 3.5: "Could not load file or assembly 'System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies. The module was expected to contain an assembly manifest." I've tried numerous fixes, such as reinstalling through ad/remove software, copying the .net folder over from a clean windows 7 install, and running the .net cleanup tool. Just wondering if anyone has run into this issue before, or has an idea on how to fix it.

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  • Windows 7, HTTPS WebDav: Asks for password twice and fails. Any workarounds?

    - by AutoDMC
    Howdy. I have a Dav server running with PHP SabreDav (code.google.com/p/sabredav/wiki/Windows) on Cherokee at an HTTPS secured URL. It's set to use https, and uses Digest Authentication. I can log in with multiple browsers and a few third party clients (BitKinex and Java AnyClient can connect and browse as well, caveats below). However, when attempting to log in with Windows 7 (surprise, surprise), it asks for my password twice, then tells me that my folder is invalid. I have verified that the server is using Digest authentication. I've verified multiple times that third party software can connect. I even went out and bought a GoDaddy SSL certificate so my SSL wouldn't be self signed anymore. I've applied the registry hacks here: support.microsoft.com/kb/943280 (Note that the article says the "fix" already exists for Windows 7, I just need magical registry hax to get it to work) I've applied the registry hacks here: support.microsoft.com/kb/941050 I've applied the registry hacks here: support.microsoft.com/kb/841215 (Supposedly allows Basic Auth, which shouldn't apply, but why not?) All to no avail; Windows continues to ask for my password twice, then state that "The folder you entered does not appear to be valid. Please choose another." Try the command line? Sure: I've attempted to access with NET USE "https://dav.example.com/" password /USER:me (System error 59) I've attempted to access with NET USE "https://dav.example.com/" (System error 1790) I've attempted to access with NET USE "https://dav.example.com/subdir/" password /USER:me (System error 59) I've attempted to access with NET USE "https://dav.example.com/subdir/" (System error 1790) For good luck: ping dav.example.com ... works. And again, web browsers can access the share just fine, so can third party tools. Best I can tell at this point is "HAHA, NO WEBDAV FOR YOU ON WINDOWS 7" which would be fine except everyone who will be using this application... uses Windows 7. And most are not as persistent or pugnacious as I am. I feel like I've burned through every random suggestion I've found anywhere in the first 10 pages of Google on every search term I can think of. Any ideas? I need it to be Webdav, I need it to be over HTTPS, and I really do need a method to access it from Windows 7. EXTRA DETAIL: However, the "third party" programs I've tried have either been buggy, incomplete, or have silly ... "glitches." For example, BitKinex seems to fixate on any http error codes sent, so if there's a glitch reading a directory, BAM, that directory is always listed empty. Long directory listings also show up as blank, even though the transfer panel shows that directory listing is still taking place. In any case, BitKinex is useless for development purposes for the reasons above. And besides, I'm building this for people other than myself, people who will want to get this dav share working "the regular way."

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  • Deploying an MVC 2.0 .Net 4.0 application to Windows Server 2003

    - by Brett Rigby
    I've spent the past couple of nights on this, and have come to the conclusions that I'm doing something wrong! Basically, I have my .Net 4.0 MVC 2.0 application deployed to my 2003 Server and it's constantly giving me the following error: The value for the 'compilerVersion' attribute in the provider options must be 'v4.0' or later if you are compiling for version 4.0 or later of the .NET Framework. To compile this Web application for version 3.5 or earlier of the .NET Framework, remove the 'targetFramework' attribute from the element of the Web.config file. I also have the .Net 3.5 MVC 1.0 application also deployed to the same server (from before the upgrade to .Net 4.0), and it works absolutely fine. I have re-run through Phil Haack's post on IIS6, making the necessary changes for .Net 4.0, but no luck. I have been through the steps in the British Developer's post too, but no joy. I have also tried the steps outlined in Johan's blog post, but the settings he mentions were already enabled. Obviously, I can't simply upgrade to a 2008 box, nor do I want to downgrade my software back to < 4.0 - any other ideas?

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  • How to Put Javascript into an ASP.NET MVC View

    - by Maxim Z.
    I'm really new to ASP.NET MVC, and I'm trying to integrate some Javascript into a website I'm making as a test of this technology. My question is this: how can I insert Javascript code into a View? Let's say that I start out with the default ASP.NET MVC template. In terms of Views, this creates a Master page, a "Home" View, and an "About" view. The "Home" View, called Index.aspx, looks like this: <%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage" %> <asp:Content ID="indexTitle" ContentPlaceHolderID="TitleContent" runat="server"> Home Page </asp:Content> <asp:Content ID="indexContent" ContentPlaceHolderID="MainContent" runat="server"> <h2><%= Html.Encode(ViewData["Message"]) %></h2> <p> To learn more about ASP.NET MVC visit <a href="http://asp.net/mvc" title="ASP.NET MVC Website">http://asp.net/mvc</a>. </p> <p>Welcome to this testing site!</p> </asp:Content> Adding a <script> tag here didn't work. Where and how should I do it? P.S.: I have a feeling I'm missing something very basic... Thanks in advance!

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  • "Unable to read data from the transport connection: net_io_connectionclosed." - Windows Vista Busine

    - by John DaCosta
    Unable to test sending email from .NET code in Windows Vista Business. I am writing code which I will migrate to an SSIS Package once it its proven. The code is to send an error message via email to a list of recipients. The code is below, however I am getting an exception when I execute the code. I created a simple class to do the mailing... the design could be better, I am testing functionality before implementing more robust functionality, methods, etc. namespace LabDemos { class Program { static void Main(string[] args) { Mailer m = new Mailer(); m.test(); } } } namespace LabDemos { class MyMailer { List<string> _to = new List<string>(); List<string> _cc = new List<string>(); List<string> _bcc = new List<string>(); String _msgFrom = ""; String _msgSubject = ""; String _msgBody = ""; public void test(){ //create the mail message MailMessage mail = new MailMessage(); //set the addresses mail.From = new MailAddress("[email protected]"); //set the content mail.Subject = "This is an email"; mail.Body = "this is a sample body"; mail.IsBodyHtml = false; //send the message SmtpClient smtp = new SmtpClient(); smtp.Host = "emailservername"; smtp.Port = 25; smtp.UseDefaultCredentials = true; smtp.Send(mail); } } Exception Message Inner Exception {"Unable to read data from the transport connection: net_io_connectionclosed."} Stack Trace " at System.Net.Mail.SmtpReplyReaderFactory.ProcessRead(Byte[] buffer, Int32 offset, Int32 read, Boolean readLine)\r\n at System.Net.Mail.SmtpReplyReaderFactory.ReadLines(SmtpReplyReader caller, Boolean oneLine)\r\n at System.Net.Mail.SmtpReplyReaderFactory.ReadLine(SmtpReplyReader caller)\r\n at System.Net.Mail.SmtpConnection.GetConnection(String host, Int32 port)\r\n at System.Net.Mail.SmtpTransport.GetConnection(String host, Int32 port)\r\n at System.Net.Mail.SmtpClient.GetConnection()\r\n at System.Net.Mail.SmtpClient.Send(MailMessage message)" Outer Exception System.Net.Mail.SmtpException was unhandled Message="Failure sending mail." Source="System" StackTrace: at System.Net.Mail.SmtpClient.Send(MailMessage message) at LabDemos.Mailer.test() in C:\Users\username\Documents\Visual Studio 2008\Projects\LabDemos\LabDemos\Mailer.cs:line 40 at LabDemos.Program.Main(String[] args) in C:\Users\username\Documents\Visual Studio 2008\Projects\LabDemos\LabDemos\Program.cs:line 48 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.nExecuteAssembly(Assembly assembly, String[] args) at System.Runtime.Hosting.ManifestRunner.Run(Boolean checkAptModel) at System.Runtime.Hosting.ManifestRunner.ExecuteAsAssembly() at System.Runtime.Hosting.ApplicationActivator.CreateInstance(ActivationContext activationContext, String[] activationCustomData) at System.Runtime.Hosting.ApplicationActivator.CreateInstance(ActivationContext activationContext) at System.Activator.CreateInstance(ActivationContext activationContext) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssemblyDebugInZone() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart() InnerException: System.IO.IOException Message="Unable to read data from the transport connection: net_io_connectionclosed." Source="System" StackTrace: at System.Net.Mail.SmtpReplyReaderFactory.ProcessRead(Byte[] buffer, Int32 offset, Int32 read, Boolean readLine) at System.Net.Mail.SmtpReplyReaderFactory.ReadLines(SmtpReplyReader caller, Boolean oneLine) at System.Net.Mail.SmtpReplyReaderFactory.ReadLine(SmtpReplyReader caller) at System.Net.Mail.SmtpConnection.GetConnection(String host, Int32 port) at System.Net.Mail.SmtpTransport.GetConnection(String host, Int32 port) at System.Net.Mail.SmtpClient.GetConnection() at System.Net.Mail.SmtpClient.Send(MailMessage message) InnerException:

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  • Parallelism in .NET – Part 14, The Different Forms of Task

    - by Reed
    Before discussing Task creation and actual usage in concurrent environments, I will briefly expand upon my introduction of the Task class and provide a short explanation of the distinct forms of Task.  The Task Parallel Library includes four distinct, though related, variations on the Task class. In my introduction to the Task class, I focused on the most basic version of Task.  This version of Task, the standard Task class, is most often used with an Action delegate.  This allows you to implement for each task within the task decomposition as a single delegate. Typically, when using the new threading constructs in .NET 4 and the Task Parallel Library, we use lambda expressions to define anonymous methods.  The advantage of using a lambda expression is that it allows the Action delegate to directly use variables in the calling scope.  This eliminates the need to make separate Task classes for Action<T>, Action<T1,T2>, and all of the other Action<…> delegate types.  As an example, suppose we wanted to make a Task to handle the ”Show Splash” task from our earlier decomposition.  Even if this task required parameters, such as a message to display, we could still use an Action delegate specified via a lambda: // Store this as a local variable string messageForSplashScreen = GetSplashScreenMessage(); // Create our task Task showSplashTask = new Task( () => { // We can use variables in our outer scope, // as well as methods scoped to our class! this.DisplaySplashScreen(messageForSplashScreen); }); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This provides a huge amount of flexibility.  We can use this single form of task for any task which performs an operation, provided the only information we need to track is whether the task has completed successfully or not.  This leads to my first observation: Use a Task with a System.Action delegate for any task for which no result is generated. This observation leads to an obvious corollary: we also need a way to define a task which generates a result.  The Task Parallel Library provides this via the Task<TResult> class. Task<TResult> subclasses the standard Task class, providing one additional feature – the ability to return a value back to the user of the task.  This is done by switching from providing an Action delegate to providing a Func<TResult> delegate.  If we decompose our problem, and we realize we have one task where its result is required by a future operation, this can be handled via Task<TResult>.  For example, suppose we want to make a task for our “Check for Update” task, we could do: Task<bool> checkForUpdateTask = new Task<bool>( () => { return this.CheckWebsiteForUpdate(); }); Later, we would start this task, and perform some other work.  At any point in the future, we could get the value from the Task<TResult>.Result property, which will cause our thread to block until the task has finished processing: // This uses Task<bool> checkForUpdateTask generated above... // Start the task, typically on a background thread checkForUpdateTask.Start(); // Do some other work on our current thread this.DoSomeWork(); // Discover, from our background task, whether an update is available // This will block until our task completes bool updateAvailable = checkForUpdateTask.Result; This leads me to my second observation: Use a Task<TResult> with a System.Func<TResult> delegate for any task which generates a result. Task and Task<TResult> provide a much cleaner alternative to the previous Asynchronous Programming design patterns in the .NET framework.  Instead of trying to implement IAsyncResult, and providing BeginXXX() and EndXXX() methods, implementing an asynchronous programming API can be as simple as creating a method that returns a Task or Task<TResult>.  The client side of the pattern also is dramatically simplified – the client can call a method, then either choose to call task.Wait() or use task.Result when it needs to wait for the operation’s completion. While this provides a much cleaner model for future APIs, there is quite a bit of infrastructure built around the current Asynchronous Programming design patterns.  In order to provide a model to work with existing APIs, two other forms of Task exist.  There is a constructor for Task which takes an Action<Object> and a state parameter.  In addition, there is a constructor for creating a Task<TResult> which takes a Func<Object, TResult> as well as a state parameter.  When using these constructors, the state parameter is stored in the Task.AsyncState property. While these two overloads exist, and are usable directly, I strongly recommend avoiding this for new development.  The two forms of Task which take an object state parameter exist primarily for interoperability with traditional .NET Asynchronous Programming methodologies.  Using lambda expressions to capture variables from the scope of the creator is a much cleaner approach than using the untyped state parameters, since lambda expressions provide full type safety without introducing new variables.

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  • Parallelism in .NET – Part 6, Declarative Data Parallelism

    - by Reed
    When working with a problem that can be decomposed by data, we have a collection, and some operation being performed upon the collection.  I’ve demonstrated how this can be parallelized using the Task Parallel Library and imperative programming using imperative data parallelism via the Parallel class.  While this provides a huge step forward in terms of power and capabilities, in many cases, special care must still be given for relative common scenarios. C# 3.0 and Visual Basic 9.0 introduced a new, declarative programming model to .NET via the LINQ Project.  When working with collections, we can now write software that describes what we want to occur without having to explicitly state how the program should accomplish the task.  By taking advantage of LINQ, many operations become much shorter, more elegant, and easier to understand and maintain.  Version 4.0 of the .NET framework extends this concept into the parallel computation space by introducing Parallel LINQ. Before we delve into PLINQ, let’s begin with a short discussion of LINQ.  LINQ, the extensions to the .NET Framework which implement language integrated query, set, and transform operations, is implemented in many flavors.  For our purposes, we are interested in LINQ to Objects.  When dealing with parallelizing a routine, we typically are dealing with in-memory data storage.  More data-access oriented LINQ variants, such as LINQ to SQL and LINQ to Entities in the Entity Framework fall outside of our concern, since the parallelism there is the concern of the data base engine processing the query itself. LINQ (LINQ to Objects in particular) works by implementing a series of extension methods, most of which work on IEnumerable<T>.  The language enhancements use these extension methods to create a very concise, readable alternative to using traditional foreach statement.  For example, let’s revisit our minimum aggregation routine we wrote in Part 4: double min = double.MaxValue; foreach(var item in collection) { double value = item.PerformComputation(); min = System.Math.Min(min, value); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, we’re doing a very simple computation, but writing this in an imperative style.  This can be loosely translated to English as: Create a very large number, and save it in min Loop through each item in the collection. For every item: Perform some computation, and save the result If the computation is less than min, set min to the computation Although this is fairly easy to follow, it’s quite a few lines of code, and it requires us to read through the code, step by step, line by line, in order to understand the intention of the developer. We can rework this same statement, using LINQ: double min = collection.Min(item => item.PerformComputation()); Here, we’re after the same information.  However, this is written using a declarative programming style.  When we see this code, we’d naturally translate this to English as: Save the Min value of collection, determined via calling item.PerformComputation() That’s it – instead of multiple logical steps, we have one single, declarative request.  This makes the developer’s intentions very clear, and very easy to follow.  The system is free to implement this using whatever method required. Parallel LINQ (PLINQ) extends LINQ to Objects to support parallel operations.  This is a perfect fit in many cases when you have a problem that can be decomposed by data.  To show this, let’s again refer to our minimum aggregation routine from Part 4, but this time, let’s review our final, parallelized version: // Safe, and fast! double min = double.MaxValue; // Make a "lock" object object syncObject = new object(); Parallel.ForEach( collection, // First, we provide a local state initialization delegate. () => double.MaxValue, // Next, we supply the body, which takes the original item, loop state, // and local state, and returns a new local state (item, loopState, localState) => { double value = item.PerformComputation(); return System.Math.Min(localState, value); }, // Finally, we provide an Action<TLocal>, to "merge" results together localState => { // This requires locking, but it's only once per used thread lock(syncObj) min = System.Math.Min(min, localState); } ); Here, we’re doing the same computation as above, but fully parallelized.  Describing this in English becomes quite a feat: Create a very large number, and save it in min Create a temporary object we can use for locking Call Parallel.ForEach, specifying three delegates For the first delegate: Initialize a local variable to hold the local state to a very large number For the second delegate: For each item in the collection, perform some computation, save the result If the result is less than our local state, save the result in local state For the final delegate: Take a lock on our temporary object to protect our min variable Save the min of our min and local state variables Although this solves our problem, and does it in a very efficient way, we’ve created a set of code that is quite a bit more difficult to understand and maintain. PLINQ provides us with a very nice alternative.  In order to use PLINQ, we need to learn one new extension method that works on IEnumerable<T> – ParallelEnumerable.AsParallel(). That’s all we need to learn in order to use PLINQ: one single method.  We can write our minimum aggregation in PLINQ very simply: double min = collection.AsParallel().Min(item => item.PerformComputation()); By simply adding “.AsParallel()” to our LINQ to Objects query, we converted this to using PLINQ and running this computation in parallel!  This can be loosely translated into English easily, as well: Process the collection in parallel Get the Minimum value, determined by calling PerformComputation on each item Here, our intention is very clear and easy to understand.  We just want to perform the same operation we did in serial, but run it “as parallel”.  PLINQ completely extends LINQ to Objects: the entire functionality of LINQ to Objects is available.  By simply adding a call to AsParallel(), we can specify that a collection should be processed in parallel.  This is simple, safe, and incredibly useful.

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  • Triple boot vista xp ubuntu

    - by Artyom2033
    My partition table is pretty messed up from install/uninstall os and what I want to do now is to clear that and have vista/xp/ubuntu 12.04 on the same hard drive. I have create a new partition for xp on vista, everything was fine, but when I restarted my pc, I was getting the grub restore prompt. Even when I was trying to install xp, when the 'lunch windows' came, a wild BSOD appear. So I have deleted my partition for xp using gParted include in the 12.04 live cd. This haven't resolve the problem and I am still unable to boot in vista nor ubuntu. But I realy what this triple boot for LoL purpose (since my vista installation keep giving latency spike in this game and I hope this will not be the case in a fresh xp installation (I have tested it in ubuntu, the ping was good, but the fps wasn't). So what I want to do, is to install xp on a partition, then be able to boot on any of them without a problem from a nice installation of grub or something. gParted screenshot Thanks for help. Sorry for my English.

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  • How to host customer developed code server side

    - by user963263
    I'm developing a multi-tenant web application, most likely using ASP.NET MVC5 and Web API. I have used business applications in the past where it was possible to upload custom DLL's or paste in custom code to a GUI to have custom functions run server side. These applications were self hosted and single-tenant though so the customer developed bits didn't impact other clients. I want to host the multi-tenant web application myself and allow customers to upload custom code that will run server side. This could be for things like custom web services that client side JavaScript could interact with, or it could be for automation steps that they want triggered server side asynchronously when a user takes a particular action. Additionally, I want to expose an API that allows customers' code to interact with data specific to the web application itself. Client code may need to be "wrapped" so that it has access to appropriate references - to our custom API and maybe to a white list of approved libraries. There are several issues to consider - security, performance (infinite loops, otherwise poorly written code, load balancing, etc.), receive compiled DLL's or require raw code, etc. Is there an established pattern for this sort of thing or a sample project anyone can point to? Or any general recommendations?

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  • Remote Desktop - remote computer that was reached is not the one you specified

    - by Jim McKeeth
    We just setup some new Windows 2008 R2 servers and we are unable to Remote Desktop into them from our Windows 7 desktops. Remote desktop connects, but after we provide credentials we get: The connection cannot be completed because the remote computer that was reached is not the one you specified. This could be caused by an outdated entry in the DNS cache. Try using the IP address of the computer instead of the name. If we connect from Windows 7 to a machine not running Windows 2008 R2, or from a machine not running Windows 7 to the Windows 2008 R2 server, it works fine. Likewise if we connect to the Windows 2008 R2 server from Windows 7 via the IP address then it works fine (although that causes other problems later). I've only found one other mention of someone having this problem, so I don't think it is just our network. Any suggestions on how to connect from Windows 7 to Windows 2008 R2 via DNS? Both are 64-bit. Update: Turns out it does not need to be R2 to get the error. We have another server that is Windows 2008 R1 64-bit that also fails.

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  • Windows CE vs Windows Mobile

    - by Vaccano
    I often see these terms: Windows CE Windows Mobile Pocket PC Windows Mobile Smart Phone I know the difference between the second 2, but I am confused on the first. I thought it was the name of the Mobile OS prior to Windows Mobile 5. But I am seeing it more often in current products. (Here is a current MS Form for developing on it. Here is a current product for creating them.) What is it and how does it relate to the Windows Mobile lines?

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  • Using an alternate JSON Serializer in ASP.NET Web API

    - by Rick Strahl
    The new ASP.NET Web API that Microsoft released alongside MVC 4.0 Beta last week is a great framework for building REST and AJAX APIs. I've been working with it for quite a while now and I really like the way it works and the complete set of features it provides 'in the box'. It's about time that Microsoft gets a decent API for building generic HTTP endpoints into the framework. DataContractJsonSerializer sucks As nice as Web API's overall design is one thing still sucks: The built-in JSON Serialization uses the DataContractJsonSerializer which is just too limiting for many scenarios. The biggest issues I have with it are: No support for untyped values (object, dynamic, Anonymous Types) MS AJAX style Date Formatting Ugly serialization formats for types like Dictionaries To me the most serious issue is dealing with serialization of untyped objects. I have number of applications with AJAX front ends that dynamically reformat data from business objects to fit a specific message format that certain UI components require. The most common scenario I have there are IEnumerable query results from a database with fields from the result set rearranged to fit the sometimes unconventional formats required for the UI components (like jqGrid for example). Creating custom types to fit these messages seems like overkill and projections using Linq makes this much easier to code up. Alas DataContractJsonSerializer doesn't support it. Neither does DataContractSerializer for XML output for that matter. What this means is that you can't do stuff like this in Web API out of the box:public object GetAnonymousType() { return new { name = "Rick", company = "West Wind", entered= DateTime.Now }; } Basically anything that doesn't have an explicit type DataContractJsonSerializer will not let you return. FWIW, the same is true for XmlSerializer which also doesn't work with non-typed values for serialization. The example above is obviously contrived with a hardcoded object graph, but it's not uncommon to get dynamic values returned from queries that have anonymous types for their result projections. Apparently there's a good possibility that Microsoft will ship Json.NET as part of Web API RTM release.  Scott Hanselman confirmed this as a footnote in his JSON Dates post a few days ago. I've heard several other people from Microsoft confirm that Json.NET will be included and be the default JSON serializer, but no details yet in what capacity it will show up. Let's hope it ends up as the default in the box. Meanwhile this post will show you how you can use it today with the beta and get JSON that matches what you should see in the RTM version. What about JsonValue? To be fair Web API DOES include a new JsonValue/JsonObject/JsonArray type that allow you to address some of these scenarios. JsonValue is a new type in the System.Json assembly that can be used to build up an object graph based on a dictionary. It's actually a really cool implementation of a dynamic type that allows you to create an object graph and spit it out to JSON without having to create .NET type first. JsonValue can also receive a JSON string and parse it without having to actually load it into a .NET type (which is something that's been missing in the core framework). This is really useful if you get a JSON result from an arbitrary service and you don't want to explicitly create a mapping type for the data returned. For serialization you can create an object structure on the fly and pass it back as part of an Web API action method like this:public JsonValue GetJsonValue() { dynamic json = new JsonObject(); json.name = "Rick"; json.company = "West Wind"; json.entered = DateTime.Now; dynamic address = new JsonObject(); address.street = "32 Kaiea"; address.zip = "96779"; json.address = address; dynamic phones = new JsonArray(); json.phoneNumbers = phones; dynamic phone = new JsonObject(); phone.type = "Home"; phone.number = "808 123-1233"; phones.Add(phone); phone = new JsonObject(); phone.type = "Home"; phone.number = "808 123-1233"; phones.Add(phone); //var jsonString = json.ToString(); return json; } which produces the following output (formatted here for easier reading):{ name: "rick", company: "West Wind", entered: "2012-03-08T15:33:19.673-10:00", address: { street: "32 Kaiea", zip: "96779" }, phoneNumbers: [ { type: "Home", number: "808 123-1233" }, { type: "Mobile", number: "808 123-1234" }] } If you need to build a simple JSON type on the fly these types work great. But if you have an existing type - or worse a query result/list that's already formatted JsonValue et al. become a pain to work with. As far as I can see there's no way to just throw an object instance at JsonValue and have it convert into JsonValue dictionary. It's a manual process. Using alternate Serializers in Web API So, currently the default serializer in WebAPI is DataContractJsonSeriaizer and I don't like it. You may not either, but luckily you can swap the serializer fairly easily. If you'd rather use the JavaScriptSerializer built into System.Web.Extensions or Json.NET today, it's not too difficult to create a custom MediaTypeFormatter that uses these serializers and can replace or partially replace the native serializer. Here's a MediaTypeFormatter implementation using the ASP.NET JavaScriptSerializer:using System; using System.Net.Http.Formatting; using System.Threading.Tasks; using System.Web.Script.Serialization; using System.Json; using System.IO; namespace Westwind.Web.WebApi { public class JavaScriptSerializerFormatter : MediaTypeFormatter { public JavaScriptSerializerFormatter() { SupportedMediaTypes.Add(new System.Net.Http.Headers.MediaTypeHeaderValue("application/json")); } protected override bool CanWriteType(Type type) { // don't serialize JsonValue structure use default for that if (type == typeof(JsonValue) || type == typeof(JsonObject) || type== typeof(JsonArray) ) return false; return true; } protected override bool CanReadType(Type type) { if (type == typeof(IKeyValueModel)) return false; return true; } protected override System.Threading.Tasks.Taskobject OnReadFromStreamAsync(Type type, System.IO.Stream stream, System.Net.Http.Headers.HttpContentHeaders contentHeaders, FormatterContext formatterContext) { var task = Taskobject.Factory.StartNew(() = { var ser = new JavaScriptSerializer(); string json; using (var sr = new StreamReader(stream)) { json = sr.ReadToEnd(); sr.Close(); } object val = ser.Deserialize(json,type); return val; }); return task; } protected override System.Threading.Tasks.Task OnWriteToStreamAsync(Type type, object value, System.IO.Stream stream, System.Net.Http.Headers.HttpContentHeaders contentHeaders, FormatterContext formatterContext, System.Net.TransportContext transportContext) { var task = Task.Factory.StartNew( () = { var ser = new JavaScriptSerializer(); var json = ser.Serialize(value); byte[] buf = System.Text.Encoding.Default.GetBytes(json); stream.Write(buf,0,buf.Length); stream.Flush(); }); return task; } } } Formatter implementation is pretty simple: You override 4 methods to tell which types you can handle and then handle the input or output streams to create/parse the JSON data. Note that when creating output you want to take care to still allow JsonValue/JsonObject/JsonArray types to be handled by the default serializer so those objects serialize properly - if you let either JavaScriptSerializer or JSON.NET handle them they'd try to render the dictionaries which is very undesirable. If you'd rather use Json.NET here's the JSON.NET version of the formatter:// this code requires a reference to JSON.NET in your project #if true using System; using System.Net.Http.Formatting; using System.Threading.Tasks; using System.Web.Script.Serialization; using System.Json; using Newtonsoft.Json; using System.IO; using Newtonsoft.Json.Converters; namespace Westwind.Web.WebApi { public class JsonNetFormatter : MediaTypeFormatter { public JsonNetFormatter() { SupportedMediaTypes.Add(new System.Net.Http.Headers.MediaTypeHeaderValue("application/json")); } protected override bool CanWriteType(Type type) { // don't serialize JsonValue structure use default for that if (type == typeof(JsonValue) || type == typeof(JsonObject) || type == typeof(JsonArray)) return false; return true; } protected override bool CanReadType(Type type) { if (type == typeof(IKeyValueModel)) return false; return true; } protected override System.Threading.Tasks.Taskobject OnReadFromStreamAsync(Type type, System.IO.Stream stream, System.Net.Http.Headers.HttpContentHeaders contentHeaders, FormatterContext formatterContext) { var task = Taskobject.Factory.StartNew(() = { var settings = new JsonSerializerSettings() { NullValueHandling = NullValueHandling.Ignore, }; var sr = new StreamReader(stream); var jreader = new JsonTextReader(sr); var ser = new JsonSerializer(); ser.Converters.Add(new IsoDateTimeConverter()); object val = ser.Deserialize(jreader, type); return val; }); return task; } protected override System.Threading.Tasks.Task OnWriteToStreamAsync(Type type, object value, System.IO.Stream stream, System.Net.Http.Headers.HttpContentHeaders contentHeaders, FormatterContext formatterContext, System.Net.TransportContext transportContext) { var task = Task.Factory.StartNew( () = { var settings = new JsonSerializerSettings() { NullValueHandling = NullValueHandling.Ignore, }; string json = JsonConvert.SerializeObject(value, Formatting.Indented, new JsonConverter[1] { new IsoDateTimeConverter() } ); byte[] buf = System.Text.Encoding.Default.GetBytes(json); stream.Write(buf,0,buf.Length); stream.Flush(); }); return task; } } } #endif   One advantage of the Json.NET serializer is that you can specify a few options on how things are formatted and handled. You get null value handling and you can plug in the IsoDateTimeConverter which is nice to product proper ISO dates that I would expect any Json serializer to output these days. Hooking up the Formatters Once you've created the custom formatters you need to enable them for your Web API application. To do this use the GlobalConfiguration.Configuration object and add the formatter to the Formatters collection. Here's what this looks like hooked up from Application_Start in a Web project:protected void Application_Start(object sender, EventArgs e) { // Action based routing (used for RPC calls) RouteTable.Routes.MapHttpRoute( name: "StockApi", routeTemplate: "stocks/{action}/{symbol}", defaults: new { symbol = RouteParameter.Optional, controller = "StockApi" } ); // WebApi Configuration to hook up formatters and message handlers // optional RegisterApis(GlobalConfiguration.Configuration); } public static void RegisterApis(HttpConfiguration config) { // Add JavaScriptSerializer formatter instead - add at top to make default //config.Formatters.Insert(0, new JavaScriptSerializerFormatter()); // Add Json.net formatter - add at the top so it fires first! // This leaves the old one in place so JsonValue/JsonObject/JsonArray still are handled config.Formatters.Insert(0, new JsonNetFormatter()); } One thing to remember here is the GlobalConfiguration object which is Web API's static configuration instance. I think this thing is seriously misnamed given that GlobalConfiguration could stand for anything and so is hard to discover if you don't know what you're looking for. How about WebApiConfiguration or something more descriptive? Anyway, once you know what it is you can use the Formatters collection to insert your custom formatter. Note that I insert my formatter at the top of the list so it takes precedence over the default formatter. I also am not removing the old formatter because I still want JsonValue/JsonObject/JsonArray to be handled by the default serialization mechanism. Since they process in sequence and I exclude processing for these types JsonValue et al. still get properly serialized/deserialized. Summary Currently DataContractJsonSerializer in Web API is a pain, but at least we have the ability with relatively limited effort to replace the MediaTypeFormatter and plug in our own JSON serializer. This is useful for many scenarios - if you have existing client applications that used MVC JsonResult or ASP.NET AJAX results from ASMX AJAX services you can plug in the JavaScript serializer and get exactly the same serializer you used in the past so your results will be the same and don't potentially break clients. JSON serializers do vary a bit in how they serialize some of the more complex types (like Dictionaries and dates for example) and so if you're migrating it might be helpful to ensure your client code doesn't break when you switch to ASP.NET Web API. Going forward it looks like Microsoft is planning on plugging in Json.Net into Web API and make that the default. I think that's an awesome choice since Json.net has been around forever, is fast and easy to use and provides a ton of functionality as part of this great library. I just wish Microsoft would have figured this out sooner instead of now at the last minute integrating with it especially given that Json.Net has a similar set of lower level JSON objects JsonValue/JsonObject etc. which now will end up being duplicated by the native System.Json stuff. It's not like we don't already have enough confusion regarding which JSON serializer to use (JavaScriptSerializer, DataContractJsonSerializer, JsonValue/JsonObject/JsonArray and now Json.net). For years I've been using my own JSON serializer because the built in choices are both limited. However, with an official encorsement of Json.Net I'm happily moving on to use that in my applications. Let's see and hope Microsoft gets this right before ASP.NET Web API goes gold.© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api  AJAX  ASP.NET   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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  • Parallelism in .NET – Part 20, Using Task with Existing APIs

    - by Reed
    Although the Task class provides a huge amount of flexibility for handling asynchronous actions, the .NET Framework still contains a large number of APIs that are based on the previous asynchronous programming model.  While Task and Task<T> provide a much nicer syntax as well as extending the flexibility, allowing features such as continuations based on multiple tasks, the existing APIs don’t directly support this workflow. There is a method in the TaskFactory class which can be used to adapt the existing APIs to the new Task class: TaskFactory.FromAsync.  This method provides a way to convert from the BeginOperation/EndOperation method pair syntax common through .NET Framework directly to a Task<T> containing the results of the operation in the task’s Result parameter. While this method does exist, it unfortunately comes at a cost – the method overloads are far from simple to decipher, and the resulting code is not always as easily understood as newer code based directly on the Task class.  For example, a single call to handle WebRequest.BeginGetResponse/EndGetReponse, one of the easiest “pairs” of methods to use, looks like the following: var task = Task.Factory.FromAsync<WebResponse>( request.BeginGetResponse, request.EndGetResponse, null); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The compiler is unfortunately unable to infer the correct type, and, as a result, the WebReponse must be explicitly mentioned in the method call.  As a result, I typically recommend wrapping this into an extension method to ease use.  For example, I would place the above in an extension method like: public static class WebRequestExtensions { public static Task<WebResponse> GetReponseAsync(this WebRequest request) { return Task.Factory.FromAsync<WebResponse>( request.BeginGetResponse, request.EndGetResponse, null); } } This dramatically simplifies usage.  For example, if we wanted to asynchronously check to see if this blog supported XHTML 1.0, and report that in a text box to the user, we could do: var webRequest = WebRequest.Create("http://www.reedcopsey.com"); webRequest.GetReponseAsync().ContinueWith(t => { using (var sr = new StreamReader(t.Result.GetResponseStream())) { string str = sr.ReadLine();; this.textBox1.Text = string.Format("Page at {0} supports XHTML 1.0: {1}", t.Result.ResponseUri, str.Contains("XHTML 1.0")); } }, TaskScheduler.FromCurrentSynchronizationContext());   By using a continuation with a TaskScheduler based on the current synchronization context, we can keep this request asynchronous, check based on the first line of the response string, and report the results back on our UI directly.

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  • How to restore windows.old for windows 7

    - by Jim Thio
    I reinstall windows. Then I regret that and want to go back. Fortunately the old windows is stored at windows.old I follow the instruction in http://support.microsoft.com/kb/971760 I did it all with small catches When I insert the windows 7 installer, the drive for installer is X and my hard disk is D rather than C. However, on normal windows operation the drive is C. Only when I boot through CD the partition is assigned to the letter D. There is no file bootsect on my windows installer So I can't do **D:\boot\bootsect /nt60 c:** Which should be changed to X:\boot\bootsect /nt60 C: or X:\boot\bootsect /nt60 D: depending on what it really does. As I said if I boot through windows dvd my hard disk letter is D but normally it's C. I am not even sure what that bootsect does anyway. I also can't do this one Attrib –h –s –r boot.ini.saved Copy boot.ini.saved boot.ini There is no file boot.ini or boot.ini.saved It's hidden but I don't see it if I try to look unhidden files either. Because I simply switch from windows 7 to windows 7 and the directory for windows don't change c:\windows I thought it should still work. Well, it doesn't. When windows restart it only goes to the logo and then restart the computer.

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  • Drop Down Box and other stuff in ASP.NET with VB.NET (VS 2008)

    - by typoknig
    Hi all, I am trying to polish up a program a program that I have converted from a Windows Form in to an ASP.NET Web Application. I have several questions: 1.) I have a drop down box where users can select their variables, but users can also enter their variables manually into various text fields. What I want is for the drop down box to show a string like "Choose Variables" when ever the user enters their variables manually. I want this to happen without having to reload the page. 2.) In the Windows Form version of this application I had a RichTextBox that populated with data (line by line) after a calculation was made. I used "AppendText" in my Windows Form, but that is not available in ASP.NET, and neither is the RichTextBox. I am open to suggestions here, I tried to use just a text box but that isn't working right. 3.) In my Windows Form application I was using "KeyPress" events to prevent incorrect characters from being entered into the text fields. My code for these events looked similar to this: Private Sub TextBox_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox.KeyPress If (e.KeyChar < "0" OrElse e.KeyChar > "9") AndAlso e.KeyChar <> ControlChars.Back AndAlso e.KeyChar <> "." Then e.Handled = True End If End Sub How can I make this work again... also without reloading the page. 4.) This is not a major issue, but I would like all of the text to be selected when the cursor enters a field. In my Windows Form application I used "SelectAll", but again, that is not available in ASP.NET Thanks in advanced.

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  • Parallelism in .NET – Part 1, Decomposition

    - by Reed
    The first step in designing any parallelized system is Decomposition.  Decomposition is nothing more than taking a problem space and breaking it into discrete parts.  When we want to work in parallel, we need to have at least two separate things that we are trying to run.  We do this by taking our problem and decomposing it into parts. There are two common abstractions that are useful when discussing parallel decomposition: Data Decomposition and Task Decomposition.  These two abstractions allow us to think about our problem in a way that helps leads us to correct decision making in terms of the algorithms we’ll use to parallelize our routine. To start, I will make a couple of minor points. I’d like to stress that Decomposition has nothing to do with specific algorithms or techniques.  It’s about how you approach and think about the problem, not how you solve the problem using a specific tool, technique, or library.  Decomposing the problem is about constructing the appropriate mental model: once this is done, you can choose the appropriate design and tools, which is a subject for future posts. Decomposition, being unrelated to tools or specific techniques, is not specific to .NET in any way.  This should be the first step to parallelizing a problem, and is valid using any framework, language, or toolset.  However, this gives us a starting point – without a proper understanding of decomposition, it is difficult to understand the proper usage of specific classes and tools within the .NET framework. Data Decomposition is often the simpler abstraction to use when trying to parallelize a routine.  In order to decompose our problem domain by data, we take our entire set of data and break it into smaller, discrete portions, or chunks.  We then work on each chunk in the data set in parallel. This is particularly useful if we can process each element of data independently of the rest of the data.  In a situation like this, there are some wonderfully simple techniques we can use to take advantage of our data.  By decomposing our domain by data, we can very simply parallelize our routines.  In general, we, as developers, should be always searching for data that can be decomposed. Finding data to decompose if fairly simple, in many instances.  Data decomposition is typically used with collections of data.  Any time you have a collection of items, and you’re going to perform work on or with each of the items, you potentially have a situation where parallelism can be exploited.  This is fairly easy to do in practice: look for iteration statements in your code, such as for and foreach. Granted, every for loop is not a candidate to be parallelized.  If the collection is being modified as it’s iterated, or the processing of elements depends on other elements, the iteration block may need to be processed in serial.  However, if this is not the case, data decomposition may be possible. Let’s look at one example of how we might use data decomposition.  Suppose we were working with an image, and we were applying a simple contrast stretching filter.  When we go to apply the filter, once we know the minimum and maximum values, we can apply this to each pixel independently of the other pixels.  This means that we can easily decompose this problem based off data – we will do the same operation, in parallel, on individual chunks of data (each pixel). Task Decomposition, on the other hand, is focused on the individual tasks that need to be performed instead of focusing on the data.  In order to decompose our problem domain by tasks, we need to think about our algorithm in terms of discrete operations, or tasks, which can then later be parallelized. Task decomposition, in practice, can be a bit more tricky than data decomposition.  Here, we need to look at what our algorithm actually does, and how it performs its actions.  Once we have all of the basic steps taken into account, we can try to analyze them and determine whether there are any constraints in terms of shared data or ordering.  There are no simple things to look for in terms of finding tasks we can decompose for parallelism; every algorithm is unique in terms of its tasks, so every algorithm will have unique opportunities for task decomposition. For example, say we want our software to perform some customized actions on startup, prior to showing our main screen.  Perhaps we want to check for proper licensing, notify the user if the license is not valid, and also check for updates to the program.  Once we verify the license, and that there are no updates, we’ll start normally.  In this case, we can decompose this problem into tasks – we have a few tasks, but there are at least two discrete, independent tasks (check licensing, check for updates) which we can perform in parallel.  Once those are completed, we will continue on with our other tasks. One final note – Data Decomposition and Task Decomposition are not mutually exclusive.  Often, you’ll mix the two approaches while trying to parallelize a single routine.  It’s possible to decompose your problem based off data, then further decompose the processing of each element of data based on tasks.  This just provides a framework for thinking about our algorithms, and for discussing the problem.

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  • IE9 RC fixed the “Internet Explorer cannot display the webpage” error when running an ASP.NET application in Visual Studio

    - by Jon Galloway
    One of the obstacles ASP.NET developers faced in using the Internet Explorer 9 Beta was the dreaded “Internet Explorer cannot display the webpage” error when running an ASP.NET application in Visual Studio. In the bug information on Connect (issue 601047), Eric Lawrence said that the problem was due to “caused by failure to failover from IPv6 to IPv4 when the connection is local.” Robert MacLean gives some more information as what was going wrong: “The problem is Windows, especially since it assumes IPv6 is better than IPv4. Note […] that when you ping localhost you get an IPv6 address. So what appears to be happening is when IE9 tries to go to localhost it uses IPv6, and the ASP.NET Development Server is IPv4 only and so nothing loads and we get the error.” The Simple Fix - Install IE 9 RC Internet Explorer 9 RC fixes this bug, so if you had tried IE 9 Beta and stopped using it due to problems with ASP.NET development, install the RC. The Workaround in IE 9 Beta If you're stuck on IE 9 Beta for some reason, you can follow Robert's workaround, which involves a one character edit to your hosts file. I've been using it for months, and it works great. Open notepad (running as administrator) and edit the hosts file (found in %systemroot%\system32\drivers\etc) Remove the # comment character before the line starting with 127.0.0.1 Save the file - if you have problems saving, it's probably because you weren't running as administrator When you're done, your hosts file will end with the following lines (assuming you were using a default hosts file setup beforehand): # localhost name resolution is handled within DNS itself.     127.0.0.1       localhost #    ::1             localhost Note: more information on editing your hosts file here. This causes Windows to default to IPv4 when resolving localhost, which will point to 127.0.0.1, which is right where Cassini - I mean the ASP.NET Web Development Server - is waiting for it.

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

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

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