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• About Me

  - by Jeffrey West

  I’m new to blogging.  This is the second blog post that I have written, and before I go too much further I wanted the readers of my blog to know a bit more about me… Kid’s Stuff By trade, I am a programmer (or coder, developer, engineer, architect, etc).  I started programming when I was 12 years old.  When I was 7, we got our first ‘family’ computer – an Apple IIc.  It was great to play games on, and of course what else was a 7-year-old going to do with it.  I did have one problem with it, though.  When I put in my 5.25” floppy to play a game, sometimes, instead loading my game I would get a mysterious ‘]’ on the screen with a flashing cursor.  This, of course, was not my game.  Much like the standard ‘Microsoft fix’ is to reboot, back then you would take the floppy out, shake it, and restart the computer and pray for a different result. One day, I learned at school that I could topple my nemesis – the ‘]’ and flashing cursor – by typing ‘load’ and pressing enter.  Most of the time, this would load my game and then I would get to play.  Problem solved.  However, I began to wonder – what else can I make it do? When I was in 5th grade my dad got a bright idea to buy me a Tandy 1000HX.  He didn’t know what I was going to do with it, and neither did I.  Least of all, my mom wasn’t happy about buying a 5th grader a $1,000 computer.  Nonetheless, Over time, I learned how to write simple basic programs out of the back of my Math book: 10 x=5 20 y=6 30 PRINT x+y That was fun for all of about 5 minutes.  I needed more – more challenges, more things that I could make the computer do.  In order to quench this thirst my parents sent me to National Computer Camps in Connecticut.  It was one of the best experiences of my childhood, and I spent 3 weeks each summer after that learning BASIC, Pascal, Turbo C and some C++.  There weren’t many kids at the time who knew anything about computers, and lets just say my knowledge of and interest in computers didn’t score me many ‘cool’ points.  My experiences at NCC set me on the path that I find myself on now, and I am very thankful for the experience.  Real Life I have held various positions in the past at different levels within the IT layer cake.  I started out as a Software Developer for a startup in the Dallas, TX area building software for semiconductor testing statistical process control and sampling.  I was the second Java developer that was hired, and the ninth employee overall, so I got a great deal of experience developing software.  Since there weren’t that many people in the organization, I also got a lot of field experience which meant that if I screwed up the code, I got yelled at (figuratively) by both my boss AND the customer.  Fun Times!  What made it better was that I got to help run pilot programs in Taiwan, Singapore, Malaysia and Malta.  Getting yelled at in Taiwan is slightly less annoying that getting yelled at in Dallas… I spent the next 5 years at Accenture doing systems integration in the ‘SOA’ group.  I joined as a Consultant and left as a Senior Manager.  I started out writing code in WebLogic Integration and left after I wrapped up project where I led a team of 25 to develop the next generation of a digital media platform to deliver HD content in a digital format.  At Accenture, I had the pleasure of working with some truly amazing people – mentoring some and learning from many others – and on some incredible real-world IT projects.  Given my background with the BEA stack of products I was often called in to troubleshoot and tune WebLogic, ALBPM and ALSB installations and have logged many hours digging through thread dumps, running performance tests with SoapUI and decompiling Java classes we didn’t have the source for so I could see what was going on in the code. I am now a Senior Principal Product Manager at Oracle in the Application Grid practice.  The term ‘Application Grid’ refers to a collection of software and hardware products within Oracle that enables customers to build horizontally scalable systems.  This collection of products includes WebLogic, GlassFish, Coherence, Tuxedo and the JRockit/HotSpot JVMs (HotSprocket, maybe?).  Now, with the introduction of Exalogic it has grown to include hardware as well. Wrapping it up… I love technology and have a diverse background ranging from software development to HW and network architecture & tuning.  I have held certifications for being an Oracle Certified DBA, MSCE and Cisco Certified Network Professional (CCNP), among others and I have put those to great use over my career.  I am excited about programming & technology and I enjoy helping people learn and be successful.  If you are having challenges with WebLogic, BPM or Service Bus feel free to reach out to me and I’ll be happy to help as I have time. Thanks for stopping by!   --Jeff

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• C# async and actors

  - by Alex.Davies

  If you read my last post about async, you might be wondering what drove me to write such odd code in the first place. The short answer is that .NET Demon is written using NAct Actors. Actors are an old idea, which I believe deserve a renaissance under C# 5. The idea is to isolate each stateful object so that only one thread has access to its state at any point in time. That much should be familiar, it's equivalent to traditional lock-based synchronization. The different part is that actors pass "messages" to each other rather than calling a method and waiting for it to return. By doing that, each thread can only ever be holding one lock. This completely eliminates deadlocks, my least favourite concurrency problem. Most people who use actors take this quite literally, and there are plenty of frameworks which help you to create message classes and loops which can receive the messages, inspect what type of message they are, and process them accordingly. But I write C# for a reason. Do I really have to choose between using actors and everything I love about object orientation in C#? Type safety Interfaces Inheritance Generics As it turns out, no. You don't need to choose between messages and method calls. A method call makes a perfectly good message, as long as you don't wait for it to return. This is where asynchonous methods come in. I have used NAct for a while to wrap my objects in a proxy layer. As long as I followed the rule that methods must always return void, NAct queued up the call for later, and immediately released my thread. When I needed to get information out of other actors, I could use EventHandlers and callbacks (continuation passing style, for any CS geeks reading), and NAct would call me back in my isolated thread without blocking the actor that raised the event. Using callbacks looks horrible though. To remind you: m_BuildControl.FilterEnabledForBuilding(    projects,    enabledProjects = m_OutOfDateProjectFinder.FilterNeedsBuilding(        enabledProjects,             newDirtyProjects =             {                 ....... Which is why I'm really happy that NAct now supports async methods. Now, methods are allowed to return Task rather than just void. I can await those methods, and C# 5 will turn the rest of my method into a continuation for me. NAct will run the other method in the other actor's context, but will make sure that when my method resumes, we're back in my context. Neither actor was ever blocked waiting for the other one. Apart from when they were actually busy doing something, they were responsive to concurrent messages from other sources. To be fair, you could use async methods with lock statements to achieve exactly the same thing, but it's ugly. Here's a realistic example of an object that has a queue of data that gets passed to another object to be processed: class QueueProcessor {    private readonly ItemProcessor m_ItemProcessor = ...     private readonly object m_Sync = new object();    private Queue<object> m_DataQueue = ...    private List<object> m_Results = ...     public async Task ProcessOne() {         object data = null;         lock (m_Sync)         {             data = m_DataQueue.Dequeue();         }         var processedData = await m_ItemProcessor.ProcessData(data); lock (m_Sync)         {             m_Results.Add(processedData);         }     } } We needed to write two lock blocks, one to get the data to process, one to store the result. The worrying part is how easily we could have forgotten one of the locks. Compare that to the version using NAct: class QueueProcessorActor : IActor { private readonly ItemProcessor m_ItemProcessor = ... private Queue<object> m_DataQueue = ... private List<object> m_Results = ... public async Task ProcessOne()     {         // We are an actor, it's always thread-safe to access our private fields         var data = m_DataQueue.Dequeue();         var processedData = await m_ItemProcessor.ProcessData(data);         m_Results.Add(processedData);     } } You don't have to explicitly lock anywhere, NAct ensures that your code will only ever run on one thread, because it's an actor. Either way, async is definitely better than traditional synchronous code. Here's a diagram of what a typical synchronous implementation might do: The left side shows what is running on the thread that has the lock required to access the QueueProcessor's data. The red section is where that lock is held, but doesn't need to be. Contrast that with the async version we wrote above: Here, the lock is released in the middle. The QueueProcessor is free to do something else. Most importantly, even if the ItemProcessor sometimes calls the QueueProcessor, they can never deadlock waiting for each other. So I thoroughly recommend you use async for all code that has to wait a while for things. And if you find yourself writing lots of lock statements, think about using actors as well. Using actors and async together really takes the misery out of concurrent programming.

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• Goto for the Java Programming Language

  - by darcy

  Work on JDK 8 is well-underway, but we thought this late-breaking JEP for another language change for the platform couldn't wait another day before being published. Title: Goto for the Java Programming Language Author: Joseph D. Darcy Organization: Oracle. Created: 2012/04/01 Type: Feature State: Funded Exposure: Open Component: core/lang Scope: SE JSR: 901 MR Discussion: compiler dash dev at openjdk dot java dot net Start: 2012/Q2 Effort: XS Duration: S Template: 1.0 Reviewed-by: Duke Endorsed-by: Edsger Dijkstra Funded-by: Blue Sun Corporation Summary Provide the benefits of the time-testing goto control structure to Java programs. The Java language has a history of adding new control structures over time, the assert statement in 1.4, the enhanced for-loop in 1.5,and try-with-resources in 7. Having support for goto is long-overdue and simple to implement since the JVM already has goto instructions. Success Metrics The goto statement will allow inefficient and verbose recursive algorithms and explicit loops to be replaced with more compact code. The effort will be a success if at least twenty five percent of the JDK's explicit loops are replaced with goto's. Coordination with IDE vendors is expected to help facilitate this goal. Motivation The goto construct offers numerous benefits to the Java platform, from increased expressiveness, to more compact code, to providing new programming paradigms to appeal to a broader demographic. In JDK 8, there is a renewed focus on using the Java platform on embedded devices with more modest resources than desktop or server environments. In such contexts, static and dynamic memory footprint is a concern. One significant component of footprint is the code attribute of class files and certain classes of important algorithms can be expressed more compactly using goto than using other constructs, saving footprint. For example, to implement state machines recursively, some parties have asked for the JVM to support tail calls, that is, to perform a complex transformation with security implications to turn a method call into a goto. Such complicated machinery should not be assumed for an embedded context. A better solution is just to expose to the programmer the desired functionality, goto. The web has familiarized users with a model of traversing links among different HTML pages in a free-form fashion with some state being maintained on the side, such as login credentials, to effect behavior. This is exactly the programming model of goto and code. While in the past this has been derided as leading to "spaghetti code," spaghetti is a tasty and nutritious meal for programmers, unlike quiche. The invokedynamic instruction added by JSR 292 exposes the JVM's linkage operation to programmers. This is a low-level operation that can be leveraged by sophisticated programmers. Likewise, goto is a also a low-level operation that should not be hidden from programmers who can use more efficient idioms. Some may object that goto was consciously excluded from the original design of Java as one of the removed feature from C and C++. However, the designers of the Java programming languages have revisited these removals before. The enum construct was also left out only to be added in JDK 5 and multiple inheritance was left out, only to be added back by the virtual extension method methods of Project Lambda. As a living language, the needs of the growing Java community today should be used to judge what features are needed in the platform tomorrow; the language should not be forever bound by the decisions of the past. Description From its initial version, the JVM has had two instructions for unconditional transfer of control within a method, goto (0xa7) and goto_w (0xc8). The goto_w instruction is used for larger jumps. All versions of the Java language have supported labeled statements; however, only the break and continue statements were able to specify a particular label as a target with the onerous restriction that the label must be lexically enclosing. The grammar addition for the goto statement is: GotoStatement: goto Identifier ; The new goto statement similar to break except that the target label can be anywhere inside the method and the identifier is mandatory. The compiler simply translates the goto statement into one of the JVM goto instructions targeting the right offset in the method. Therefore, adding the goto statement to the platform is only a small effort since existing compiler and JVM functionality is reused. Other language changes to support goto include obvious updates to definite assignment analysis, reachability analysis, and exception analysis. Possible future extensions include a computed goto as found in gcc, which would replace the identifier in the goto statement with an expression having the type of a label. Testing Since goto will be implemented using largely existing facilities, only light levels of testing are needed. Impact Compatibility: Since goto is already a keyword, there are no source compatibility implications. Performance/scalability: Performance will improve with more compact code. JVMs already need to handle irreducible flow graphs since goto is a VM instruction.

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• Implementing synchronous MediaTypeFormatters in ASP.NET Web API

  - by cibrax

  One of main characteristics of MediaTypeFormatter’s in ASP.NET Web API is that they leverage the Task Parallel Library (TPL) for reading or writing an model into an stream. When you derive your class from the base class MediaTypeFormatter, you have to either implement the WriteToStreamAsync or ReadFromStreamAsync methods for writing or reading a model from a stream respectively. These two methods return a Task, which internally does all the serialization work, as it is illustrated bellow. public abstract class MediaTypeFormatter { public virtual Task WriteToStreamAsync(Type type, object value, Stream writeStream, HttpContent content, TransportContext transportContext); public virtual Task<object> ReadFromStreamAsync(Type type, Stream readStream, HttpContent content, IFormatterLogger formatterLogger); }   .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; } .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; } However, most of the times, serialization is a safe operation that can be done synchronously. In fact, many of the serializer classes you will find in the .NET framework only provide sync methods. So the question is, how you can transform that synchronous work into a Task ?. Creating a new task using the method Task.Factory.StartNew for doing all the serialization work would be probably the typical answer. That would work, as a new task is going to be scheduled. However, that might involve some unnecessary context switches, which are out of our control and might be affect performance on server code specially.   If you take a look at the source code of the MediaTypeFormatters shipped as part of the framework, you will notice that they actually using another pattern, which uses a TaskCompletionSource class. public Task WriteToStreamAsync(Type type, object value, Stream writeStream, HttpContent content, TransportContext transportContext) {   var tsc = new TaskCompletionSource<AsyncVoid>(); tsc.SetResult(default(AsyncVoid));   //Do all the serialization work here synchronously   return tsc.Task; }   /// <summary> /// Used as the T in a "conversion" of a Task into a Task{T} /// </summary> private struct AsyncVoid { } .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; } They are basically doing all the serialization work synchronously and using a TaskCompletionSource for returning a task already done. To conclude this post, this is another approach you might want to consider when using serializers that are not compatible with an async model. Update: Henrik Nielsen from the ASP.NET team pointed out the existence of a built-in media type formatter for writing sync formatters. BufferedMediaTypeFormatter http://t.co/FxOfeI5x

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• Playing with http page cycle using JustMock

  - by mehfuzh

  In this post , I will cover a test code that will mock the various elements needed to complete a HTTP page request and  assert the expected page cycle steps. To begin, i have a simple enumeration that has my predefined page steps: public enum PageStep {     PreInit,     Load,     PreRender,     UnLoad } Once doing so, i  first created the page object [not mocking]. Page page = new Page(); Here, our target is to fire up the page process through ProcessRequest call, now if we take a look inside the method with reflector.net,  the call trace will go like : ProcessRequest –> ProcessRequestWithNoAssert –> SetInstrinsics –> Finallly ProcessRequest. Inside SetInstrinsics ,  it requires calls from HttpRequest, HttpResponse and HttpBrowserCababilities. With this clue at hand, we can easily know the classes / calls  we need to mock in order to get through the expected call. Accordingly, for  HttpBrowserCapabilities our required test code will look like: Mock.Arrange(() => browser.PreferredRenderingMime).Returns("text/html"); Mock.Arrange(() => browser.PreferredResponseEncoding).Returns("UTF-8"); Mock.Arrange(() => browser.PreferredRequestEncoding).Returns("UTF-8"); Now, HttpBrowserCapabilities is get though [Instance]HttpRequest.Browser. Therefore, we create the HttpRequest mock: var request = Mock.Create<HttpRequest>(); Then , add the required get call : Mock.Arrange(() => request.Browser).Returns(browser); As, [instance]Browser.PerferrredResponseEncoding and [instance]Browser.PreferredResponseEncoding  are also set to the request object and to make that they are set properly, we can add the following lines as well [not required though]. bool requestContentEncodingSet = false; Mock.ArrangeSet(() => request.ContentEncoding = Encoding.GetEncoding("UTF-8")).DoInstead(() =>  requestContentEncodingSet = true); Similarly, for response we can write:  var response = Mock.Create<HttpResponse>();    bool responseContentEncodingSet = false;  Mock.ArrangeSet(() => response.ContentEncoding = Encoding.GetEncoding("UTF-8")).DoInstead(() => responseContentEncodingSet = true); Finally , I created a mock of HttpContext and set the Request and Response properties that will returns the mocked version. var context = Mock.Create<HttpContext>();   Mock.Arrange(() => context.Request).Returns(request); Mock.Arrange(() => context.Response).Returns(response); As, Page internally calls RenderControl method , we just need to replace that with our one and optionally we can check if  invoked properly: bool rendered = false; Mock.Arrange(() => page.RenderControl(Arg.Any<HtmlTextWriter>())).DoInstead(() => rendered = true); That’s  it, the rest of the code is simple,  where  i asserted the page cycle with the PageSteps that i defined earlier: var pageSteps = new Queue<PageStep>();   page.PreInit +=      delegate      {          pageSteps.Enqueue(PageStep.PreInit);      }; page.Load +=      delegate      {          pageSteps.Enqueue(PageStep.Load);      };   page.PreRender +=      delegate      {          pageSteps.Enqueue(PageStep.PreRender);      };   page.Unload +=      delegate      {          pageSteps.Enqueue(PageStep.UnLoad);      };   page.ProcessRequest(context);    Assert.True(requestContentEncodingSet);  Assert.True(responseContentEncodingSet);  Assert.True(rendered);    Assert.Equal(pageSteps.Dequeue(), PageStep.PreInit);  Assert.Equal(pageSteps.Dequeue(), PageStep.Load);  Assert.Equal(pageSteps.Dequeue(), PageStep.PreRender);  Assert.Equal(pageSteps.Dequeue(), PageStep.UnLoad);    Mock.Assert(request);  Mock.Assert(response);   You can get the test class shown in this post here to give a try by yourself with of course JustMock :-).   Enjoy!!

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• How to build a Singleton-like dependency injector replacement (Php)

  - by Erparom

  I know out there are a lot of excelent containers, even frameworks almost entirely DI based with good strong IoC classes. However, this doesn't help me to "define" a new pattern. (This is Php code but understandable to anyone) Supose we have: //Declares the singleton class bookSingleton { private $author; private static $bookInstance; private static $isLoaned = FALSE; //The private constructor private function __constructor() { $this->author = "Onecrappy Writer Ofcheap Novels"; } //Sets the global isLoaned state and also gets self instance public static function loanBook() { if (self::$isLoaned === FALSE) { //Book already taken, so return false return FALSE; } else { //Ok, not loaned, lets instantiate (if needed and loan) if (!isset(self::$bookInstance)) { self::$bookInstance = new BookSingleton(); } self::$isLoaned = TRUE; } } //Return loaned state to false, so another book reader can take the book public function returnBook() { $self::$isLoaned = FALSE; } public function getAuthor() { return $this->author; } } Then we get the singelton consumtion class: //Consumes the Singleton class BookBorrower() { private $borrowedBook; private $haveBookState; public function __construct() { this->haveBookState = FALSE; } //Use the singelton-pattern behavior public function borrowBook() { $this->borrowedBook = BookSingleton::loanBook(); //Check if was successfully borrowed if (!this->borrowedBook) { $this->haveBookState = FALSE; } else { $this->haveBookState = TRUE; } } public function returnBook() { $this->borrowedBook->returnBook(); $this->haveBookState = FALSE; } public function getBook() { if ($this->haveBookState) { return "The book is loaned, the author is" . $this->borrowedbook->getAuthor(); } else { return "I don't have the book, perhaps someone else took it"; } } } At last, we got a client, to test the behavior function __autoload($class) { require_once $class . '.php'; } function write ($whatever,$breaks) { for($break = 0;$break<$breaks;$break++) { $whatever .= "\n"; } echo nl2br($whatever); } write("Begin Singleton test", 2); $borrowerJuan = new BookBorrower(); $borrowerPedro = new BookBorrower(); write("Juan asks for the book", 1); $borrowerJuan->borrowBook(); write("Book Borrowed? ", 1); write($borrowerJuan->getAuthorAndTitle(),2); write("Pedro asks for the book", 1); $borrowerPedro->borrowBook(); write("Book Borrowed? ", 1); write($borrowerPedro->getAuthorAndTitle(),2); write("Juan returns the book", 1); $borrowerJuan->returnBook(); write("Returned Book Juan? ", 1); write($borrowerJuan->getAuthorAndTitle(),2); write("Pedro asks again for the book", 1); $borrowerPedro->borrowBook(); write("Book Borrowed? ", 1); write($borrowerPedro->getAuthorAndTitle(),2); This will end up in the expected behavior: Begin Singleton test Juan asks for the book Book Borrowed? The book is loaned, the author is = Onecrappy Writer Ofcheap Novels Pedro asks for the book Book Borrowed? I don't have the book, perhaps someone else took it Juan returns the book Returned Book Juan? I don't have the book, perhaps someone else took it Pedro asks again for the book Book Borrowed? The book is loaned, the author is = Onecrappy Writer Ofcheap Novels So I want to make a pattern based on the DI technique able to do exactly the same, but without singleton pattern. As far as I'm aware, I KNOW I must inject the book inside "borrowBook" function instead of taking a static instance: public function borrowBook(BookNonSingleton $book) { if (isset($this->borrowedBook) || $book->isLoaned()) { $this->haveBook = FALSE; return FALSE; } else { $this->borrowedBook = $book; $this->haveBook = TRUE; return TRUE; } } And at the client, just handle the book: $borrowerJuan = new BookBorrower(); $borrowerJuan-borrowBook(new NonSingletonBook()); Etc... and so far so good, BUT... Im taking the responsability of "single instance" to the borrower, instead of keeping that responsability inside the NonSingletonBook, that since it has not anymore a private constructor, can be instantiated as many times... making instances on each call. So, What does my NonSingletonBook class MUST be in order to never allow borrowers to have this same book twice? (aka) keep the single instance. Because the dependency injector part of the code (borrower) does not solve me this AT ALL. Is it needed the container with an "asShared" method builder with static behavior? No way to encapsulate this functionallity into the Book itself? "Hey Im a book and I shouldn't be instantiated more than once, I'm unique"

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• Integrating Windows Form Click Once Application into SharePoint 2007 &ndash; Part 2 of 4

  - by Kelly Jones

  In my last post, I explained why we decided to use a Click Once application to solve our business problem. To quickly review, we needed a way for our business users to upload documents to a SharePoint 2007 document library in mass, set the meta data, set the permissions per document, and to do so easily. Let’s look at the pieces that make up our solution.  First, we have the Windows Form application.  This app is deployed using Click Once and calls SharePoint web services in order to upload files and then calls web services to set the meta data (SharePoint columns and permissions).  Second, we have a custom action.  The custom action is responsible for providing our users a link that will launch the Windows app, as well as passing values to it via the query string.  And lastly, we have the web services that the Windows Form application calls.  For our solution, we used both out of the box web services and a custom web service in order to set the column values in the document library as well as the permissions on the documents. Now, let’s look at the technical details of each of these pieces.  (All of the code is downloadable from here: )   Windows Form application deployed via Click Once The Windows Form application, called “Custom Upload”, has just a few classes in it: Custom Upload -- the form FileList.xsd -- the dataset used to track the names of the files and their meta data values SharePointUpload -- this class handles uploading the file SharePointUpload uses an HttpWebRequest to transfer the file to the web server. We had to change this code from a WebClient object to the HttpWebRequest object, because we needed to be able to set the time out value.  public bool UploadDocument(string localFilename, string remoteFilename) { bool result = true; //Need to use an HttpWebRequest object instead of a WebClient object // so we can set the timeout (WebClient doesn't allow you to set the timeout!) HttpWebRequest req = (HttpWebRequest)WebRequest.Create(remoteFilename); try { req.Method = "PUT"; req.Timeout = 60 * 1000; //convert seconds to milliseconds req.AllowWriteStreamBuffering = true; req.Credentials = System.Net.CredentialCache.DefaultCredentials; req.SendChunked = false; req.KeepAlive = true; Stream reqStream = req.GetRequestStream(); FileStream rdr = new FileStream(localFilename, FileMode.Open, FileAccess.Read); byte[] inData = new byte[4096]; int bytesRead = rdr.Read(inData, 0, inData.Length); while (bytesRead > 0) { reqStream.Write(inData, 0, bytesRead); bytesRead = rdr.Read(inData, 0, inData.Length); } reqStream.Close(); rdr.Close(); System.Net.HttpWebResponse response = (HttpWebResponse)req.GetResponse(); if (response.StatusCode != HttpStatusCode.OK && response.StatusCode != HttpStatusCode.Created) { String msg = String.Format("An error occurred while uploading this file: {0}\n\nError response code: {1}", System.IO.Path.GetFileName(localFilename), response.StatusCode.ToString()); LogWarning(msg, "2ACFFCCA-59BA-40c8-A9AB-05FA3331D223"); result = false; } } catch (Exception ex) { LogException(ex, "{E9D62A93-D298-470d-A6BA-19AAB237978A}"); result = false; } return result; } The class also contains the LogException() and LogWarning() methods. When the application is launched, it parses the query string for some initial values.  The query string looks like this: string queryString = "Srv=clickonce&Sec=N&Doc=DMI&SiteName=&Speed=128000&Max=50"; This Srv is the path to the server (my Virtual Machine is name “clickonce”), the Sec is short for security – meaning HTTPS or HTTP, the Doc is the shortcut for which document library to use, and SiteName is the name of the SharePoint site.  Speed is used to calculate an estimate for download speed for each file.  We added this so our users uploading documents would realize how long it might take for clients in remote locations (using slow WAN connections) to download the documents. The last value, Max, is the maximum size that the SharePoint site will allow documents to be.  This allowed us to give users a warning that a file is too large before we even attempt to upload it. Another critical piece is the meta data collection.  We organized our site using SharePoint content types, so when the app loads, it gets a list of the document library’s content types.  The user then select one of the content types from the drop down list, and then we query SharePoint to get a list of the fields that make up that content type.  We used both an out of the box web service, and one that we custom built, in order to get these values. Once we have the content type fields, we then add controls to the form.  Which type of control we add depends on the data type of the field.  (DateTime pickers for date/time fields, etc)  We didn’t write code to cover every data type, since we were working with a limited set of content types and field data types. Here’s a screen shot of the Form, before and after someone has selected the content types and our code has added the custom controls:     The other piece of meta data we collect is the in the upper right corner of the app, “Users with access”.  This box lists the different SharePoint Groups that we have set up and by checking the boxes, the user can set the permissions on the uploaded documents. All of this meta data is collected and submitted to our custom web service, which then sets the values on the documents on the list.  We’ll look at these web services in a future post. In the next post, we’ll walk through the Custom Action we built.

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• Why enumerator structs are a really bad idea

  - by Simon Cooper

  If you've ever poked around the .NET class libraries in Reflector, I'm sure you would have noticed that the generic collection classes all have implementations of their IEnumerator as a struct rather than a class. As you will see, this design decision has some rather unfortunate side effects... As is generally known in the .NET world, mutable structs are a Very Bad Idea; and there are several other blogs around explaining this (Eric Lippert's blog post explains the problem quite well). In the BCL, the generic collection enumerators are all mutable structs, as they need to keep track of where they are in the collection. This bit me quite hard when I was coding a wrapper around a LinkedList<int>.Enumerator. It boils down to this code: sealed class EnumeratorWrapper : IEnumerator<int> { private readonly LinkedList<int>.Enumerator m_Enumerator; public EnumeratorWrapper(LinkedList<int> linkedList) { m_Enumerator = linkedList.GetEnumerator(); } public int Current { get { return m_Enumerator.Current; } } object System.Collections.IEnumerator.Current { get { return Current; } } public bool MoveNext() { return m_Enumerator.MoveNext(); } public void Reset() { ((System.Collections.IEnumerator)m_Enumerator).Reset(); } public void Dispose() { m_Enumerator.Dispose(); } } The key line here is the MoveNext method. When I initially coded this, I thought that the call to m_Enumerator.MoveNext() would alter the enumerator state in the m_Enumerator class variable and so the enumeration would proceed in an orderly fashion through the collection. However, when I ran this code it went into an infinite loop - the m_Enumerator.MoveNext() call wasn't actually changing the state in the m_Enumerator variable at all, and my code was looping forever on the first collection element. It was only after disassembling that method that I found out what was going on The MoveNext method above results in the following IL: .method public hidebysig newslot virtual final instance bool MoveNext() cil managed { .maxstack 1 .locals init ( [0] bool CS$1$0000, [1] valuetype [System]System.Collections.Generic.LinkedList`1/Enumerator CS$0$0001) L_0000: nop L_0001: ldarg.0 L_0002: ldfld valuetype [System]System.Collections.Generic.LinkedList`1/Enumerator EnumeratorWrapper::m_Enumerator L_0007: stloc.1 L_0008: ldloca.s CS$0$0001 L_000a: call instance bool [System]System.Collections.Generic.LinkedList`1/Enumerator::MoveNext() L_000f: stloc.0 L_0010: br.s L_0012 L_0012: ldloc.0 L_0013: ret } Here, the important line is 0002 - m_Enumerator is accessed using the ldfld operator, which does the following: Finds the value of a field in the object whose reference is currently on the evaluation stack. So, what the MoveNext method is doing is the following: public bool MoveNext() { LinkedList<int>.Enumerator CS$0$0001 = this.m_Enumerator; bool CS$1$0000 = CS$0$0001.MoveNext(); return CS$1$0000; } The enumerator instance being modified by the call to MoveNext is the one stored in the CS$0$0001 variable on the stack, and not the one in the EnumeratorWrapper class instance. Hence why the state of m_Enumerator wasn't getting updated. Hmm, ok. Well, why is it doing this? If you have a read of Eric Lippert's blog post about this issue, you'll notice he quotes a few sections of the C# spec. In particular, 7.5.4: ...if the field is readonly and the reference occurs outside an instance constructor of the class in which the field is declared, then the result is a value, namely the value of the field I in the object referenced by E. And my m_Enumerator field is readonly! Indeed, if I remove the readonly from the class variable then the problem goes away, and the code works as expected. The IL confirms this: .method public hidebysig newslot virtual final instance bool MoveNext() cil managed { .maxstack 1 .locals init ( [0] bool CS$1$0000) L_0000: nop L_0001: ldarg.0 L_0002: ldflda valuetype [System]System.Collections.Generic.LinkedList`1/Enumerator EnumeratorWrapper::m_Enumerator L_0007: call instance bool [System]System.Collections.Generic.LinkedList`1/Enumerator::MoveNext() L_000c: stloc.0 L_000d: br.s L_000f L_000f: ldloc.0 L_0010: ret } Notice on line 0002, instead of the ldfld we had before, we've got a ldflda, which does this: Finds the address of a field in the object whose reference is currently on the evaluation stack. Instead of loading the value, we're loading the address of the m_Enumerator field. So now the call to MoveNext modifies the enumerator stored in the class rather than on the stack, and everything works as expected. Previously, I had thought enumerator structs were an odd but interesting feature of the BCL that I had used in the past to do linked list slices. However, effects like this only underline how dangerous mutable structs are, and I'm at a loss to explain why the enumerators were implemented as structs in the first place. (interestingly, the SortedList<TKey, TValue> enumerator is a struct but is private, which makes it even more odd - the only way it can be accessed is as a boxed IEnumerator!). I would love to hear people's theories as to why the enumerators are implemented in such a fashion. And bonus points if you can explain why LinkedList<int>.Enumerator.Reset is an explicit implementation but Dispose is implicit... Note to self: never ever ever code a mutable struct.

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• Some non-generic collections

  - by Simon Cooper

  Although the collections classes introduced in .NET 2, 3.5 and 4 cover most scenarios, there are still some .NET 1 collections that don't have generic counterparts. In this post, I'll be examining what they do, why you might use them, and some things you'll need to bear in mind when doing so. BitArray System.Collections.BitArray is conceptually the same as a List<bool>, but whereas List<bool> stores each boolean in a single byte (as that's what the backing bool[] does), BitArray uses a single bit to store each value, and uses various bitmasks to access each bit individually. This means that BitArray is eight times smaller than a List<bool>. Furthermore, BitArray has some useful functions for bitmasks, like And, Xor and Not, and it's not limited to 32 or 64 bits; a BitArray can hold as many bits as you need. However, it's not all roses and kittens. There are some fundamental limitations you have to bear in mind when using BitArray: It's a non-generic collection. The enumerator returns object (a boxed boolean), rather than an unboxed bool. This means that if you do this: foreach (bool b in bitArray) { ... } Every single boolean value will be boxed, then unboxed. And if you do this: foreach (var b in bitArray) { ... } you'll have to manually unbox b on every iteration, as it'll come out of the enumerator an object. Instead, you should manually iterate over the collection using a for loop: for (int i=0; i<bitArray.Length; i++) { bool b = bitArray[i]; ... } Following on from that, if you want to use BitArray in the context of an IEnumerable<bool>, ICollection<bool> or IList<bool>, you'll need to write a wrapper class, or use the Enumerable.Cast<bool> extension method (although Cast would box and unbox every value you get out of it). There is no Add or Remove method. You specify the number of bits you need in the constructor, and that's what you get. You can change the length yourself using the Length property setter though. It doesn't implement IList. Although not really important if you're writing a generic wrapper around it, it is something to bear in mind if you're using it with pre-generic code. However, if you use BitArray carefully, it can provide significant gains over a List<bool> for functionality and efficiency of space. OrderedDictionary System.Collections.Specialized.OrderedDictionary does exactly what you would expect - it's an IDictionary that maintains items in the order they are added. It does this by storing key/value pairs in a Hashtable (to get O(1) key lookup) and an ArrayList (to maintain the order). You can access values by key or index, and insert or remove items at a particular index. The enumerator returns items in index order. However, the Keys and Values properties return ICollection, not IList, as you might expect; CopyTo doesn't maintain the same ordering, as it copies from the backing Hashtable, not ArrayList; and any operations that insert or remove items from the middle of the collection are O(n), just like a normal list. In short; don't use this class. If you need some sort of ordered dictionary, it would be better to write your own generic dictionary combining a Dictionary<TKey, TValue> and List<KeyValuePair<TKey, TValue>> or List<TKey> for your specific situation. ListDictionary and HybridDictionary To look at why you might want to use ListDictionary or HybridDictionary, we need to examine the performance of these dictionaries compared to Hashtable and Dictionary<object, object>. For this test, I added n items to each collection, then randomly accessed n/2 items: So, what's going on here? Well, ListDictionary is implemented as a linked list of key/value pairs; all operations on the dictionary require an O(n) search through the list. However, for small n, the constant factor that big-o notation doesn't measure is much lower than the hashing overhead of Hashtable or Dictionary. HybridDictionary combines a Hashtable and ListDictionary; for small n, it uses a backing ListDictionary, but switches to a Hashtable when it gets to 9 items (you can see the point it switches from a ListDictionary to Hashtable in the graph). Apart from that, it's got very similar performance to Hashtable. So why would you want to use either of these? In short, you wouldn't. Any gain in performance by using ListDictionary over Dictionary<TKey, TValue> would be offset by the generic dictionary not having to cast or box the items you store, something the graphs above don't measure. Only if the performance of the dictionary is vital, the dictionary will hold less than 30 items, and you don't need type safety, would you use ListDictionary over the generic Dictionary. And even then, there's probably more useful performance gains you can make elsewhere.

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• problems with my slotgame [delphi]

  - by Raiden2k

  hey guys im coding at the moment on a slotgame for the learning effect. here is the source code. my questions are below: unit Unit1; {$mode objfpc}{$H+} interface uses Classes, SysUtils, Windows, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls, ExtCtrls, ComCtrls, Menus, ActnList, Spin, FileCtrl; type { TForm1 } TForm1 = class(TForm) FloatSpinEdit1: TFloatSpinEdit; Guthabenlb: TLabel; s4: TLabel; s5: TLabel; s6: TLabel; s7: TLabel; s8: TLabel; s9: TLabel; Timer3: TTimer; Winlb: TLabel; Loselb: TLabel; slotbn: TButton; s1: TLabel; s2: TLabel; s3: TLabel; Timer1: TTimer; Timer2: TTimer; procedure FormCreate(Sender: TObject); procedure slotbnClick(Sender: TObject); procedure Timer1Timer(Sender: TObject); procedure Timer2Timer(Sender: TObject); procedure Timer3Timer(Sender: TObject); private { private declarations } FRollen : array [0..2, 0..9] of String; public { public declarations } end; var Form1: TForm1; wins,loses : Integer; guthaben : Double = 10; implementation {$R *.lfm} { TForm1 } procedure TForm1.slotbnClick(Sender: TObject); begin Guthaben := Guthaben - 1.00; Guthabenlb.Caption := FloatToStr(guthaben) + (' €'); Timer1.Enabled := True; Timer2.Enabled := True; slotbn.Enabled := false; end; procedure TForm1.FormCreate(Sender: TObject); var i: integer; j: integer; n: integer; digits: TStringlist; begin Digits := TStringList.Create; try for i := low(FRollen) to high(FRollen) do begin for j := low(FRollen[i]) to high(FRollen[i]) do Digits.Add(IntToStr(j)); for j := low(FRollen[i]) to high(FRollen[i]) do begin n := Random(Digits.Count); FRollen[i, j] := Digits[n]; Digits.Delete(n); end; end finally Digits.Free; end; for i:=low(FRollen) to high(FRollen) do begin end; end; //==================================================================================================\\ // Drehen der Slots im Zufallsmodus //==================================================================================================// procedure TForm1.Timer1Timer(Sender: TObject); begin s1.Caption := IntToStr(Random(9)); s2.Caption := IntToStr(Random(9)); s3.Caption := IntToStr(Random(9)); s4.Caption := IntToStr(Random(9)); s5.Caption := IntToStr(Random(9)); s6.Caption := IntToStr(Random(9)); s7.Caption := IntToStr(Random(9)); s8.Caption := IntToStr(Random(9)); s9.Caption := IntToStr(Random(9)); end; //==================================================================================================// //===================================================================================================\\ // Gewonnen / Verloren abfrage //===================================================================================================// procedure TForm1.Timer2Timer(Sender: TObject); begin Timer1.Enabled := False; Timer2.Enabled := false; if (s1.Caption = s5.Caption) and (s1.Caption = s9.Caption) then begin Guthaben := Guthaben + 5.00; Inc(wins); end else if (s1.Caption = s4.Caption) and (s1.Caption = s7.Caption) then begin Guthaben := Guthaben + 5.00; Inc(wins); end else if (s2.Caption = s5.Caption) and (s2.Caption = s8.Caption) then begin Guthaben := Guthaben + 5.00; Inc(wins); end else if (s3.Caption = s6.Caption) and (s3.Caption = s9.Caption) then begin Guthaben := Guthaben + 5.00; Inc(wins); end else if (s3.Caption = s5.Caption) and (s3.Caption = s7.Caption) then begin Guthaben := Guthaben + 5.00; Inc(wins); end else Inc(loses); slotbn.Enabled := True; Loselb.Caption := 'Loses: ' + IntToStr(loses); Winlb.Caption := 'Wins: ' + IntTostr(Wins); end; procedure TForm1.Timer3Timer(Sender: TObject); begin if (guthaben = 0) or (guthaben < 0) then begin Timer3.Enabled := False; MessageBox(handle,'Du hast verloren!','Verlierer!',MB_OK); close(); end; end; //======================================================================================================\\ end. How can i replace the labels through icons 16 x 16 pixels? How can i adjust the winning sum according to the icons.(for example 3 crowns give you 40 € and 3 apples only 10 €) How can i adhust the winning sum with a sum for every round?

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• When does "proper" programming no longer matter?

  - by Kai Qing

  I've been a full time programmer for about 8 years now. Web based mostly, ranging in weird jobs for clients. Never anything I "want" to do. So my experience is limited to what I've been contracted to do, having no real incentive to master anything in particular. So here's my scenario and ultimately what I wonder about... I've been building an android game in my spare time. It's using the libgdx library so quite a bit of the heavy lifting is done for me. I don't read much of the docs cause unless it's in tutorial format I will just not care, and ultimately most of my questions have already been asked on stackoverflow. I get along fine and my game works as expected... Suspiciously well, even. So much so that I wonder why one should bother to be "proper" when coding if the end result is ultimately the same. To be more specific, I used a hashtable because I wanted something close to an associative array. Human readable key values. In other places to achieve similar things, I use a vector. I know libgdx has vector2 and vector3 classes, but I've never used them. When I come across weird problems and search stackoverflow for help, I see a lot of people just reaming the questions that use a certain datatype when another one is technically "proper." Like using an ArrayList because it does not require defined bounds versus re-defining an int[] with new known boundaries. Or even something trivial like this: for(int i = 0; i < items.length; i ++) { // do something } I know it evaluates item.length on every iteration. I just don't care. I know items will never be more than 15 to 20 items. So why bother caring if I evaluate items.length on every iteration? So I wonder - why does everyone get all up in arms over this? Who cares if I use a less efficient datatype to get the job done? I ran some tests to see how the app performs using the lazy, get it done fast and don't look back method I just described versus the proper, follow the tutorial and use the exact data types suggested by the community. The results: Same thing. Average 45 fps. I opened every app on the phone and galaxy tab. Same deal. No difference. My game is pretty graphic intensive. It's not like it's just a simple thing. I expected it to perform kind of badly since I don't care to optimize image assets or... well, you probably get the idea. I'm making the game for fun. As a joke, really. But in doing so I'm working outside the normal scope of my job, which is to always follow the rules and do it the right way. So to say, I am without bounds here and this has caused me to wonder why I ever really care to be "proper" So I guess my question to you is this: Is there a threshold when it no longer matters to be proper? Is there a lasting, longer term consequence to the lazy, get it done and don't look back route? Is it ok to say - "so long as it gets the job done, I don't care?" Disclaimer: When I program my game, I am almost always drunk. I do it to remember why I got into this stuff to begin with because the monotony of client based web work will make you hate being a programmer. I'm having a blast and my game is not crashing, tests well, performs well, looks good on all devices so far and has no noticeable negative impact on any of my testing devices. I expected failure because I was being so drunkenly careless with my code, but to my surprise, it had no noticeable impact. I am now starting to question the need to be careful. Help me regain the ability to care! ... or explain why it's not a bad thing to not care. Secondary disclaimer: I am aware of the benefits of maintainability. For myself and others. Agreed. But it's not like someone happening across my inefficient int[] loop won't know what it does. As an experienced programmer those kinds of things are just clear on sight. I document the complex stuff for myself knowing I was drunk and will probably need a reminder. Those notes would clarify any confusion for someone who might ever gaze upon my ridiculous game - though the reality is that either I maintain it myself or it fades into time. I'm ok with that. But if it doesn't slow the device down, or crash, then crossing the t's and dotting the i's might actually require more time than it's worth.

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• C#/.NET Little Wonders: Static Char Methods

  - by James Michael Hare

  Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Often times in our code we deal with the bigger classes and types in the BCL, and occasionally forgot that there are some nice methods on the primitive types as well.  Today we will discuss some of the handy static methods that exist on the char (the C# alias of System.Char) type. The Background I was examining a piece of code this week where I saw the following: 1: // need to get the 5th (offset 4) character in upper case 2: var type = symbol.Substring(4, 1).ToUpper(); 3:  4: // test to see if the type is P 5: if (type == "P") 6: { 7: // ... do something with P type... 8: } Is there really any error in this code?  No, but it still struck me wrong because it is allocating two very short-lived throw-away strings, just to store and manipulate a single char: The call to Substring() generates a new string of length 1 The call to ToUpper() generates a new upper-case version of the string from Step 1. In my mind this is similar to using ToUpper() to do a case-insensitive compare: it isn’t wrong, it’s just much heavier than it needs to be (for more info on case-insensitive compares, see #2 in 5 More Little Wonders). One of my favorite books is the C++ Coding Standards: 101 Rules, Guidelines, and Best Practices by Sutter and Alexandrescu.  True, it’s about C++ standards, but there’s also some great general programming advice in there, including two rules I love:         8. Don’t Optimize Prematurely         9. Don’t Pessimize Prematurely We all know what #8 means: don’t optimize when there is no immediate need, especially at the expense of readability and maintainability.  I firmly believe this and in the axiom: it’s easier to make correct code fast than to make fast code correct.  Optimizing code to the point that it becomes difficult to maintain often gains little and often gives you little bang for the buck. But what about #9?  Well, for that they state: “All other things being equal, notably code complexity and readability, certain efficient design patterns and coding idioms should just flow naturally from your fingertips and are no harder to write then the pessimized alternatives. This is not premature optimization; it is avoiding gratuitous pessimization.” Or, if I may paraphrase: “where it doesn’t increase the code complexity and readability, prefer the more efficient option”. The example code above was one of those times I feel where we are violating a tacit C# coding idiom: avoid creating unnecessary temporary strings.  The code creates temporary strings to hold one char, which is just unnecessary.  I think the original coder thought he had to do this because ToUpper() is an instance method on string but not on char.  What he didn’t know, however, is that ToUpper() does exist on char, it’s just a static method instead (though you could write an extension method to make it look instance-ish). This leads me (in a long-winded way) to my Little Wonders for the day… Static Methods of System.Char So let’s look at some of these handy, and often overlooked, static methods on the char type: IsDigit(), IsLetter(), IsLetterOrDigit(), IsPunctuation(), IsWhiteSpace() Methods to tell you whether a char (or position in a string) belongs to a category of characters. IsLower(), IsUpper() Methods that check if a char (or position in a string) is lower or upper case ToLower(), ToUpper() Methods that convert a single char to the lower or upper equivalent. For example, if you wanted to see if a string contained any lower case characters, you could do the following: 1: if (symbol.Any(c => char.IsLower(c))) 2: { 3: // ... 4: } Which, incidentally, we could use a method group to shorten the expression to: 1: if (symbol.Any(char.IsLower)) 2: { 3: // ... 4: } Or, if you wanted to verify that all of the characters in a string are digits: 1: if (symbol.All(char.IsDigit)) 2: { 3: // ... 4: } Also, for the IsXxx() methods, there are overloads that take either a char, or a string and an index, this means that these two calls are logically identical: 1: // check given a character 2: if (char.IsUpper(symbol[0])) { ... } 3:  4: // check given a string and index 5: if (char.IsUpper(symbol, 0)) { ... } Obviously, if you just have a char, then you’d just use the first form.  But if you have a string you can use either form equally well. As a side note, care should be taken when examining all the available static methods on the System.Char type, as some seem to be redundant but actually have very different purposes.  For example, there are IsDigit() and IsNumeric() methods, which sound the same on the surface, but give you different results. IsDigit() returns true if it is a base-10 digit character (‘0’, ‘1’, … ‘9’) where IsNumeric() returns true if it’s any numeric character including the characters for ½, ¼, etc. Summary To come full circle back to our opening example, I would have preferred the code be written like this: 1: // grab 5th char and take upper case version of it 2: var type = char.ToUpper(symbol[4]); 3:  4: if (type == 'P') 5: { 6: // ... do something with P type... 7: } Not only is it just as readable (if not more so), but it performs over 3x faster on my machine:    1,000,000 iterations of char method took: 30 ms, 0.000050 ms/item.    1,000,000 iterations of string method took: 101 ms, 0.000101 ms/item. It’s not only immediately faster because we don’t allocate temporary strings, but as an added bonus there less garbage to collect later as well.  To me this qualifies as a case where we are using a common C# performance idiom (don’t create unnecessary temporary strings) to make our code better. Technorati Tags: C#,CSharp,.NET,Little Wonders,char,string

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• Subterranean IL: Generics and array covariance

  - by Simon Cooper

  Arrays in .NET are curious beasts. They are the only built-in collection types in the CLR, and SZ-arrays (single dimension, zero-indexed) have their own commands and IL syntax. One of their stranger properties is they have a kind of built-in covariance long before generic variance was added in .NET 4. However, this causes a subtle but important problem with generics. First of all, we need to briefly recap on array covariance. SZ-array covariance To demonstrate, I'll tweak the classes I introduced in my previous posts: public class IncrementableClass { public int Value; public virtual void Increment(int incrementBy) { Value += incrementBy; } } public class IncrementableClassx2 : IncrementableClass { public override void Increment(int incrementBy) { base.Increment(incrementBy); base.Increment(incrementBy); } } In the CLR, SZ-arrays of reference types are implicitly convertible to arrays of the element's supertypes, all the way up to object (note that this does not apply to value types). That is, an instance of IncrementableClassx2[] can be used wherever a IncrementableClass[] or object[] is required. When an SZ-array could be used in this fashion, a run-time type check is performed when you try to insert an object into the array to make sure you're not trying to insert an instance of IncrementableClass into an IncrementableClassx2[]. This check means that the following code will compile fine but will fail at run-time: IncrementableClass[] array = new IncrementableClassx2[1]; array[0] = new IncrementableClass(); // throws ArrayTypeMismatchException These checks are enforced by the various stelem* and ldelem* il instructions in such a way as to ensure you can't insert a IncrementableClass into a IncrementableClassx2[]. For the rest of this post, however, I'm going to concentrate on the ldelema instruction. ldelema This instruction pops the array index (int32) and array reference (O) off the stack, and pushes a pointer (&) to the corresponding array element. However, unlike the ldelem instruction, the instruction's type argument must match the run-time array type exactly. This is because, once you've got a managed pointer, you can use that pointer to both load and store values in that array element using the ldind* and stind* (load/store indirect) instructions. As the same pointer can be used for both input and output to the array, the type argument to ldelema must be invariant. At the time, this was a perfectly reasonable restriction, and maintained array type-safety within managed code. However, along came generics, and with it the constrained callvirt instruction. So, what happens when we combine array covariance and constrained callvirt? .method public static void CallIncrementArrayValue() { // IncrementableClassx2[] arr = new IncrementableClassx2[1] ldc.i4.1 newarr IncrementableClassx2 // arr[0] = new IncrementableClassx2(); dup newobj instance void IncrementableClassx2::.ctor() ldc.i4.0 stelem.ref // IncrementArrayValue<IncrementableClass>(arr, 0) // here, we're treating an IncrementableClassx2[] as IncrementableClass[] dup ldc.i4.0 call void IncrementArrayValue<class IncrementableClass>(!!0[],int32) // ... ret } .method public static void IncrementArrayValue<(IncrementableClass) T>( !!T[] arr, int32 index) { // arr[index].Increment(1) ldarg.0 ldarg.1 ldelema !!T ldc.i4.1 constrained. !!T callvirt instance void IIncrementable::Increment(int32) ret } And the result: Unhandled Exception: System.ArrayTypeMismatchException: Attempted to access an element as a type incompatible with the array. at IncrementArrayValue[T](T[] arr, Int32 index) at CallIncrementArrayValue() Hmm. We're instantiating the generic method as IncrementArrayValue<IncrementableClass>, but passing in an IncrementableClassx2[], hence the ldelema instruction is failing as it's expecting an IncrementableClass[]. On features and feature conflicts What we've got here is a conflict between existing behaviour (ldelema ensuring type safety on covariant arrays) and new behaviour (managed pointers to object references used for every constrained callvirt on generic type instances). And, although this is an edge case, there is no general workaround. The generic method could be hidden behind several layers of assemblies, wrappers and interfaces that make it a requirement to use array covariance when calling the generic method. Furthermore, this will only fail at runtime, whereas compile-time safety is what generics were designed for! The solution is the readonly. prefix instruction. This modifies the ldelema instruction to ignore the exact type check for arrays of reference types, and so it lets us take the address of array elements using a covariant type to the actual run-time type of the array: .method public static void IncrementArrayValue<(IncrementableClass) T>( !!T[] arr, int32 index) { // arr[index].Increment(1) ldarg.0 ldarg.1 readonly. ldelema !!T ldc.i4.1 constrained. !!T callvirt instance void IIncrementable::Increment(int32) ret } But what about type safety? In return for ignoring the type check, the resulting controlled mutability pointer can only be used in the following situations: As the object parameter to ldfld, ldflda, stfld, call and constrained callvirt instructions As the pointer parameter to ldobj or ldind* As the source parameter to cpobj In other words, the only operations allowed are those that read from the pointer; stind* and similar that alter the pointer itself are banned. This ensures that the array element we're pointing to won't be changed to anything untoward, and so type safety within the array is maintained. This is a typical example of the maxim that whenever you add a feature to a program, you have to consider how that feature interacts with every single one of the existing features. Although an edge case, the readonly. prefix instruction ensures that generics and array covariance work together and that compile-time type safety is maintained. Tune in next time for a look at the .ctor generic type constraint, and what it means.

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• Is this how dynamic language copes with dynamic requirement?

  - by Amumu

  The question is in the title. I want to have my thinking verified by experienced people. You can add more or disregard my opinion, but give me a reason. Here is an example requirement: Suppose you are required to implement a fighting game. Initially, the game only includes fighters, who can attack each other. Each fighter can punch, kick or block incoming attacks. Fighters can have various fighting styles: Karate, Judo, Kung Fu... That's it for the simple universe of the game. In an OO like Java, it can be implemented similar to this way: abstract class Fighter { int hp, attack; void punch(Fighter otherFighter); void kick(Fighter otherFighter); void block(Figther otherFighter); }; class KarateFighter extends Fighter { //...implementation...}; class JudoFighter extends Fighter { //...implementation... }; class KungFuFighter extends Fighter { //...implementation ... }; This is fine if the game stays like this forever. But, somehow the game designers decide to change the theme of the game: instead of a simple fighting game, the game evolves to become a RPG, in which characters can not only fight but perform other activities, i.e. the character can be a priest, an accountant, a scientist etc... At this point, to make it more generic, we have to change the structure of our original design: Fighter is not used to refer to a person anymore; it refers to a profession. The specialized classes of Fighter (KaraterFighter, JudoFighter, KungFuFighter) . Now we have to create a generic class named Person. However, to adapt this change, I have to change the method signatures of the original operations: class Person { int hp, attack; List<Profession> skillSet; }; abstract class Profession {}; class Fighter extends Profession { void punch(Person otherFighter); void kick(Person otherFighter); void block(Person otherFighter); }; class KarateFighter extends Fighter { //...implementation...}; class JudoFighter extends Fighter { //...implementation... }; class KungFuFighter extends Fighter { //...implementation ... }; class Accountant extends Profession { void calculateTax(Person p) { //...implementation...}; void calculateTax(Company c) { //...implementation...}; }; //... more professions... Here are the problems: To adapt to the method changes, I have to fix the places where the changed methods are called (refactoring). Every time a new requirement is introduced, the current structural design has to be broken to adapt the changes. This leads to the first problem. Rigid structure makes it hard for code reuse. A function can only accept the predefined types, but it cannot accept future unknown types. A written function is bound to its current universe and has no way to accommodate to the new types, without modifications or rewrite from scratch. I see Java has a lot of deprecated methods. OO is an extreme case because it has inheritance to add up the complexity, but in general for statically typed language, types are very strict. In contrast, a dynamic language can handle the above case as follow: ;;fighter1 punch fighter2 (defun perform-punch (fighter1 fighter2) ...implementation... ) ;;fighter1 kick fighter2 (defun perform-kick (fighter1 fighter2) ...implementation... ) ;;fighter1 blocks attacks from fighter2 (defun perform-block (fighter1 fighter2) ...implementation... ) fighter1 and fighter2 can be anything as long as it has the required data for calculation; or methods (duck typing). You don't have to change from the type Fighter to Person. In the case of Lisp, because Lisp only has a single data structure: list, it's even easier to adapt to changes. However, other dynamic languages can have similar behaviors as well. I work primarily with static languages (mainly C and Java, but working with Java was a long time ago). I started learning Lisp and some other dynamic languages this year. I can see how it helps improving my productivity.

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• The Joy Of Hex

  - by Jim Giercyk

  While working on a mainframe integration project, it occurred to me that some basic computer concepts are slipping into obscurity. For example, just about anyone can tell you that a 64-bit processor is faster than a 32-bit processer. A grade school child could tell you that a computer “speaks” in ‘1’s and ‘0’s. Some people can even tell you that there are 8 bits in a byte. However, I have found that even the most seasoned developers often can’t explain the theory behind those statements. That is not a knock on programmers; in the age of IntelliSense, what reason do we have to work with data at the bit level? Many computer theory classes treat bit-level programming as a thing of the past, no longer necessary now that storage space is plentiful. The trouble with that mindset is that the world is full of legacy systems that run programs written in the 1970’s.  Today our jobs require us to extract data from those systems, regardless of the format, and that often involves low-level programming. Because it seems knowledge of the low-level concepts is waning in recent times, I thought a review would be in order.       CHARACTER: See Spot Run HEX: 53 65 65 20 53 70 6F 74 20 52 75 6E DECIMAL: 83 101 101 32 83 112 111 116 32 82 117 110 BINARY: 01010011 01100101 01100101 00100000 01010011 01110000 01101111 01110100 00100000 01010010 01110101 01101110 In this example, I have broken down the words “See Spot Run” to a level computers can understand – machine language.     CHARACTER:  The character level is what is rendered by the computer.  A “Character Set” or “Code Page” contains 256 characters, both printable and unprintable.  Each character represents 1 BYTE of data.  For example, the character string “See Spot Run” is 12 Bytes long, exclusive of the quotation marks.  Remember, a SPACE is an unprintable character, but it still requires a byte.  In the example I have used the default Windows character set, ASCII, which you can see here:  http://www.asciitable.com/ HEX:  Hex is short for hexadecimal, or Base 16.  Humans are comfortable thinking in base ten, perhaps because they have 10 fingers and 10 toes; fingers and toes are called digits, so it’s not much of a stretch.  Computers think in Base 16, with numeric values ranging from zero to fifteen, or 0 – F.  Each decimal place has a possible 16 values as opposed to a possible 10 values in base 10.  Therefore, the number 10 in Hex is equal to the number 16 in Decimal.  DECIMAL:  The Decimal conversion is strictly for us humans to use for calculations and conversions.  It is much easier for us humans to calculate that [30 – 10 = 20] in decimal than it is for us to calculate [1E – A = 14] in Hex.  In the old days, an error in a program could be found by determining the displacement from the entry point of a module.  Since those values were dumped from the computers head, they were in hex. A programmer needed to convert them to decimal, do the equation and convert back to hex.  This gets into relative and absolute addressing, a topic for another day.  BINARY:  Binary, or machine code, is where any value can be expressed in 1s and 0s.  It is really Base 2, because each decimal place can have a possibility of only 2 characters, a 1 or a 0.  In Binary, the number 10 is equal to the number 2 in decimal. Why only 1s and 0s?  Very simply, computers are made up of lots and lots of transistors which at any given moment can be ON ( 1 ) or OFF ( 0 ).  Each transistor is a bit, and the order that the transistors fire (or not fire) is what distinguishes one value from  another in the computers head (or CPU).  Consider 32 bit vs 64 bit processing…..a 64 bit processor has the capability to read 64 transistors at a time.  A 32 bit processor can only read half as many at a time, so in theory the 64 bit processor should be much faster.  There are many more factors involved in CPU performance, but that is the fundamental difference.    DECIMAL HEX BINARY 0 0 0000 1 1 0001 2 2 0010 3 3 0011 4 4 0100 5 5 0101 6 6 0110 7 7 0111 8 8 1000 9 9 1001 10 A 1010 11 B 1011 12 C 1100 13 D 1101 14 E 1110 15 F 1111   Remember that each character is a BYTE, there are 2 HEX characters in a byte (called nibbles) and 8 BITS in a byte.  I hope you enjoyed reading about the theory of data processing.  This is just a high-level explanation, and there is much more to be learned.  It is safe to say that, no matter how advanced our programming languages and visual studios become, they are nothing more than a way to interpret bits and bytes.  There is nothing like the joy of hex to get the mind racing.

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• For Programmers familiar with ACM API? Drawing Initials [closed]

  - by user71992

  Possible Duplicate: For Programmers familiar with ACM API? Drawing Initials I came across an exercise (in the book "The Art and Science of Java" by Eric Roberts) that requires using only GArc and GLine classes to create a lettering library which draws your initials on the canvas. This should be made independent of the GLabel class. I'd like to know the correct approach to use in solving this problem. I'm not sure what I have so far is good enough (I'm thinking it's too long). The questions requires that I use a good Top-Down approach. Here's my code so far: //Passes letters to GLetter objects and draws them on the canvas package artScienceJavaExercises.chapter8; import acm.program.*; //import acm.graphics.*; public class DrawInitials extends GraphicsProgram{ public void init(){ resize(400,400); } public void run(){ //String let = readLine("Letter?: "); letter = new GLetter("l"); add(letter, (getWidth()-letter.getWidth()*2)/2, (getHeight()-letter.getHeight())/2); add(new GLetter("o"), (letter.getX()+letter.getWidth()), letter.getY()); } private GLetter letter; } //GLetter Class package artScienceJavaExercises.chapter8; import acm.graphics.*; import java.awt.*; public class GLetter extends GCompound{ private static final int ONE_THIRD = 30; private static final int ROW_2_HEIGHT = 40; private GArc[] arc = new GArc[4]; private GLine[] line = new GLine[24]; public GLetter(String s){ line[0] = new GLine(0,0, ONE_THIRD, 0); line[1] = new GLine(ONE_THIRD,0, ONE_THIRD*2, 0); line[2] = new GLine(ONE_THIRD*2,0, ONE_THIRD*3, 0); line[3] = new GLine(0,0, 0,ONE_THIRD); line[4] = new GLine(ONE_THIRD,0, ONE_THIRD, ONE_THIRD); line[5] = new GLine(ONE_THIRD*2,0, ONE_THIRD*2, ONE_THIRD); line[6] = new GLine(ONE_THIRD*3,0, ONE_THIRD*3, ONE_THIRD); line[7] = new GLine(0,ONE_THIRD, ONE_THIRD*2, ONE_THIRD); line[8] = new GLine(ONE_THIRD,ONE_THIRD, ONE_THIRD*2, ONE_THIRD); line[9] = new GLine(ONE_THIRD*2,ONE_THIRD, ONE_THIRD*3, ONE_THIRD); line[10] = new GLine(0,ONE_THIRD, 0, ONE_THIRD+ROW_2_HEIGHT); line[11] = new GLine(ONE_THIRD, ONE_THIRD, ONE_THIRD, ONE_THIRD+ROW_2_HEIGHT); line[12] = new GLine(ONE_THIRD*2,ONE_THIRD, ONE_THIRD*2, ONE_THIRD+ROW_2_HEIGHT); line[13] = new GLine(ONE_THIRD*3,ONE_THIRD, ONE_THIRD*3, ONE_THIRD+ROW_2_HEIGHT); line[14] = new GLine(0, ONE_THIRD+ROW_2_HEIGHT, ONE_THIRD, ONE_THIRD+ROW_2_HEIGHT); line[15] = new GLine(ONE_THIRD, ONE_THIRD+ROW_2_HEIGHT, ONE_THIRD*2, ONE_THIRD+ROW_2_HEIGHT); line[16] = new GLine(ONE_THIRD*2, ONE_THIRD+ROW_2_HEIGHT, ONE_THIRD*3, ONE_THIRD+ROW_2_HEIGHT); line[17] = new GLine(0, ONE_THIRD+ROW_2_HEIGHT, 0, ONE_THIRD*2+ROW_2_HEIGHT); line[18] = new GLine(ONE_THIRD, ONE_THIRD+ROW_2_HEIGHT, ONE_THIRD, ONE_THIRD*2+ROW_2_HEIGHT); line[19] = new GLine(ONE_THIRD*2, ONE_THIRD+ROW_2_HEIGHT, ONE_THIRD*2, ONE_THIRD*2+ROW_2_HEIGHT); line[20] = new GLine(ONE_THIRD*3, ONE_THIRD+ROW_2_HEIGHT, ONE_THIRD*3, ONE_THIRD*2+ROW_2_HEIGHT); line[21] = new GLine(0,ONE_THIRD*2+ROW_2_HEIGHT, ONE_THIRD, ONE_THIRD*2+ROW_2_HEIGHT); line[22] = new GLine(ONE_THIRD, ONE_THIRD*2+ROW_2_HEIGHT, ONE_THIRD*2, ONE_THIRD*2+ROW_2_HEIGHT); line[23] = new GLine(ONE_THIRD*2,ONE_THIRD*2+ROW_2_HEIGHT, ONE_THIRD*3, ONE_THIRD*2+ROW_2_HEIGHT); for(int i = 0; i<line.length; i++){ add(line[i]); line[i].setColor(Color.BLACK); line[i].setVisible(false); } arc[0] = new GArc(getWidth(), getHeight(), 106.699, 49.341); arc[1] = new GArc(getWidth(), getHeight(), 23.96, 49.341); arc[2] = new GArc(getWidth(), getHeight(), -23.96, -49.341); arc[3] = new GArc(0,0,getWidth(), getHeight(), -106.699, -49.341); for(int i = 0; i<arc.length; i++){ add(arc[i],0,0); arc[i].setColor(Color.BLACK); arc[i].setVisible(false); } paintLetter(s); } private void paintLetter(String s){ if (s.equalsIgnoreCase("l")){ turnOn(line[3]); turnOn(line[10]); turnOn(line[17]); turnOn(line[21]); turnOn(line[22]); turnOn(line[23]); } else if(s.equalsIgnoreCase("o")){ for(int i = 0; i<4; ++i){ turnOn(arc[i]); } turnOn(line[1]); turnOn(line[10]); turnOn(line[13]); turnOn(line[22]); } } private void turnOn(GObject g){ g.setVisible(true); } } I created a class (GLetter.java) with arrays for GArc and GLine objects. They are positioned in certain ways thereby turning certain Glines and/or GArcs on or off (changing visiblity) would create a pattern for a letter. This Gletter uses the if/else statements to determine which pattern to create - this makes me feel my code is too long. There is another class (DrawInitials.java) that simulates a GraphicsProgram and allows the user to pass certain letters as arguments to the GLetter object. I've used 'L' and 'O' as examples. However, I posted this because I'm not sure I'm using the right approach. That's why I need your help. I feel MY CODE IS TOO LONG! The code above is not the complete project...it only draws letters 'L' and 'O' for now.

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• Telerik Releases a new Visual Entity Designer

  Love LINQ to SQL but are concerned that it is a second class citizen? Need to connect to more databases other than SQL Server? Think that the Entity Framework is too complex? Want a domain model designer for data access that is easy, yet powerful? Then the Telerik Visual Entity Designer is for you. Built on top of Telerik OpenAccess ORM, a very mature and robust product, Teleriks Visual Entity Designer is a new way to build your domain model that is very powerful and also real easy to use. How easy? Ill show you here. First Look: Using the Telerik Visual Entity Designer To get started, you need to install the Telerik OpenAccess ORM Q1 release for Visual Studio 2008 or 2010. You dont need to use any of the Telerik OpenAccess wizards, designers, or using statements. Just right click on your project and select Add|New Item from the context menu. Choose Telerik OpenAccess Domain Model from the Visual Studio project templates. (Note to existing OpenAccess users, dont run the Enable ORM wizard or any other OpenAccess menu unless you are building OpenAccess Entities.) You will then have to specify the database backend (SQL Server, SQL Azure, Oracle, MySQL, etc) and connection. After you establish your connection, select the database objects you want to add to your domain model. You can also name your model, by default it will be NameofyourdatabaseEntityDiagrams. You can click finish here if you are comfortable, or tweak some advanced settings. Many users of domain models like to add prefixes and suffixes to classes, fields, and properties as well as handle pluralization. I personally accept the defaults, however, I hate how DBAs force underscores on me, so I click on the option to remove them. You can also tweak your namespace, mapping options, and define your own code generation template to gain further control over the outputted code. This is a very powerful feature, but for now, I will just accept the defaults.   When we click finish, you can see your domain model as a file with the .rlinq extension in the Solution Explorer. You can also bring up the visual designer to view or further tweak your model by double clicking on the model in the Solution Explorer.  Time to use the model! Writing a LINQ Query Programming against the domain model is very simple using LINQ. Just set a reference to the model (line 12 of the code below) and write a standard LINQ statement (lines 14-16).  (OpenAccess users: notice the you dont need any using statements for OpenAccess or an IObjectScope, just raw LINQ against your model.) 1: using System; 2: using System.Linq; 3: //no need for anOpenAccess using statement 4:   5: namespace ConsoleApplication3 6: { 7: class Program 8: { 9: static void Main(string[] args) 10: { 11: //a reference tothe data context 12: NorthwindEntityDiagrams dat = new NorthwindEntityDiagrams(); 13: //LINQ Statement 14: var result = from c in dat.Customers 15: where c.Country == "Germany" 16: select c; 17:   18: //Print out the company name 19: foreach (var cust in result) 20: { 21: Console.WriteLine("CompanyName: " + cust.CompanyName); 22: } 23: //keep the consolewindow open 24: Console.Read(); 25: } 26: } 27: } .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; } Lines 19-24 loop through the result of our LINQ query and displays the results. Thats it! All of the super powerful features of OpenAccess are available to you to further enhance your experience, however, in most cases this is all you need. In future posts I will show how to use the Visual Designer with some other scenarios. Stay tuned. Enjoy! Technorati Tags: Telerik,OpenAccess,LINQ 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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• .NET Security Part 4

  - by Simon Cooper

  Finally, in this series, I am going to cover some of the security issues that can trip you up when using sandboxed appdomains. DISCLAIMER: I am not a security expert, and this is by no means an exhaustive list. If you actually are writing security-critical code, then get a proper security audit of your code by a professional. The examples below are just illustrations of the sort of things that can go wrong. 1. AppDomainSetup.ApplicationBase The most obvious one is the issue covered in the MSDN documentation on creating a sandbox, in step 3 – the sandboxed appdomain has the same ApplicationBase as the controlling appdomain. So let’s explore what happens when they are the same, and an exception is thrown. In the sandboxed assembly, Sandboxed.dll (IPlugin is an interface in a partially-trusted assembly, with a single MethodToDoThings on it): public class UntrustedPlugin : MarshalByRefObject, IPlugin { // implements IPlugin.MethodToDoThings() public void MethodToDoThings() { throw new EvilException(); } } [Serializable] internal class EvilException : Exception { public override string ToString() { // show we have read access to C:\Windows // read the first 5 directories Console.WriteLine("Pwned! Mwuahahah!"); foreach (var d in Directory.EnumerateDirectories(@"C:\Windows").Take(5)) { Console.WriteLine(d.FullName); } return base.ToString(); } } And in the controlling assembly: // what can possibly go wrong? AppDomainSetup appDomainSetup = new AppDomainSetup { ApplicationBase = AppDomain.CurrentDomain.SetupInformation.ApplicationBase } // only grant permissions to execute // and to read the application base, nothing else PermissionSet restrictedPerms = new PermissionSet(PermissionState.None); restrictedPerms.AddPermission( new SecurityPermission(SecurityPermissionFlag.Execution)); restrictedPerms.AddPermission( new FileIOPermission(FileIOPermissionAccess.Read, appDomainSetup.ApplicationBase); restrictedPerms.AddPermission( new FileIOPermission(FileIOPermissionAccess.pathDiscovery, appDomainSetup.ApplicationBase); // create the sandbox AppDomain sandbox = AppDomain.CreateDomain("Sandbox", null, appDomainSetup, restrictedPerms); // execute UntrustedPlugin in the sandbox // don't crash the application if the sandbox throws an exception IPlugin o = (IPlugin)sandbox.CreateInstanceFromAndUnwrap("Sandboxed.dll", "UntrustedPlugin"); try { o.MethodToDoThings() } catch (Exception e) { Console.WriteLine(e.ToString()); } And the result? Oops. We’ve allowed a class that should be sandboxed to execute code with fully-trusted permissions! How did this happen? Well, the key is the exact meaning of the ApplicationBase property: The application base directory is where the assembly manager begins probing for assemblies. When EvilException is thrown, it propagates from the sandboxed appdomain into the controlling assembly’s appdomain (as it’s marked as Serializable). When the exception is deserialized, the CLR finds and loads the sandboxed dll into the fully-trusted appdomain. Since the controlling appdomain’s ApplicationBase directory contains the sandboxed assembly, the CLR finds and loads the assembly into a full-trust appdomain, and the evil code is executed. So the problem isn’t exactly that the sandboxed appdomain’s ApplicationBase is the same as the controlling appdomain’s, it’s that the sandboxed dll was in such a place that the controlling appdomain could find it as part of the standard assembly resolution mechanism. The sandbox then forced the assembly to load in the controlling appdomain by throwing a serializable exception that propagated outside the sandbox. The easiest fix for this is to keep the sandbox ApplicationBase well away from the ApplicationBase of the controlling appdomain, and don’t allow the sandbox permissions to access the controlling appdomain’s ApplicationBase directory. If you do this, then the sandboxed assembly can’t be accidentally loaded into the fully-trusted appdomain, and the code can’t be executed. If the plugin does try to induce the controlling appdomain to load an assembly it shouldn’t, a SerializationException will be thrown when it tries to load the assembly to deserialize the exception, and no damage will be done. 2. Loading the sandboxed dll into the application appdomain As an extension of the previous point, you shouldn’t directly reference types or methods in the sandboxed dll from your application code. That loads the assembly into the fully-trusted appdomain, and from there code in the assembly could be executed. Instead, pull out methods you want the sandboxed dll to have into an interface or class in a partially-trusted assembly you control, and execute methods via that instead (similar to the example above with the IPlugin interface). If you need to have a look at the assembly before executing it in the sandbox, either examine the assembly using reflection from within the sandbox, or load the assembly into the Reflection-only context in the application’s appdomain. The code in assemblies in the reflection-only context can’t be executed, it can only be reflected upon, thus protecting your appdomain from malicious code. 3. Incorrectly asserting permissions You should only assert permissions when you are absolutely sure they’re safe. For example, this method allows a caller read-access to any file they call this method with, including your documents, any network shares, the C:\Windows directory, etc: [SecuritySafeCritical] public static string GetFileText(string filePath) { new FileIOPermission(FileIOPermissionAccess.Read, filePath).Assert(); return File.ReadAllText(filePath); } Be careful when asserting permissions, and ensure you’re not providing a loophole sandboxed dlls can use to gain access to things they shouldn’t be able to. Conclusion Hopefully, that’s given you an idea of some of the ways it’s possible to get past the .NET security system. As I said before, this post is not exhaustive, and you certainly shouldn’t base any security-critical applications on the contents of this blog post. What this series should help with is understanding the possibilities of the security system, and what all the security attributes and classes mean and what they are used for, if you were to use the security system in the future.

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• CodePlex Daily Summary for Tuesday, October 16, 2012

  CodePlex Daily Summary for Tuesday, October 16, 2012Popular ReleasesMagelia WebStore Open-source Ecommerce software: Magelia WebStore 2.1: Scheduler Import & Export feature UTC datetime and timezone support .net 4.5 and Visual Studio 2012 migration client magelia global refactoring nugget package https://nuget.org/packages/Magelia.Webstore.Client/2.1.254.1 burst optimisation burst time improvment (multithreading, index, ...) current burst is still active when a new burst is generating bugfixes version 2.1.254.1DevLib: 70038 binary dlls: 70038 binary dllsP1 Port monitoring with Netduino Plus: V0.2 Beta Netduino Plus P1 Port Monitoring: This is the stable beta release of the Netduino Plus P1 port monitoring. Please read the requirements on the Documentation page.JayData - The cross-platform HTML5 data-management library for JavaScript: JayData 1.2.2: JayData is a unified data access library for JavaScript to CRUD + Query data from different sources like OData, MongoDB, WebSQL, SqLite, HTML5 localStorage, Facebook or YQL. The library can be integrated with Knockout.js or Sencha Touch 2 and can be used on Node.js as well. See it in action in this 6 minutes video Sencha Touch 2 example app using JayData: Netflix browser. What's new in JayData 1.2.2 For detailed release notes check the release notes. Revitalized IndexedDB providerNow you c...VFPX: FoxcodePlus: FoxcodePlus - Visual Studio like extensions to Visual FoxPro IntelliSense.Droid Explorer: Droid Explorer 0.8.8.8 Beta: fixed the icon for packages on the desktop fixed the install dialog closing right when it starts removed the link to "set up the sdk for me" as this is no longer supported. fixed bug where the device selection dialog would show, even if there was only one device connected. fixed toolbar from having "gap" between other toolbar removed main menu items that do not have any menus Iveely Search Engine: Iveely Search Engine （0.3.0）: Iveely Search Engine?????????????，0.3.0????????，????????：??????。 ????????????"????“？???????,????????????。??0.3.0??????????？0.3.0????????，????。 ?????，????????????????，??????300????，?????????300?????????????????，?????????????????。????，??????????，???????，???????。???????IveelySE.Resource，???????????，???????????????????????，???????????。 ????????Iveely.config，??????IveelySE.Run.Task.exe，?????????http://127.0.0.1:8088/query=yourkeyword，??????。 ????，??? ??http://www.cnblogs.com/liufanping...Fiskalizacija za developere: FiskalizacijaDev 1.0: Prva verzija ovog projekta, još je uvijek oznacena kao BETA - ovo znaci da su naša testiranja prošla uspješno :) No, kako mi ne proizvodimo neki software za blagajne, tako sve ovo nije niti isprobano u "realnim" uvjetima - svaka je sugestija, primjedba ili prijava bug-a je dobrodošla. Za sve ovo koristite, molimo, Discussions ili Issue Tracker. U ovom trenutku runtime binary je raspoloživ kao Any CPU za .NET verzije 2.0. Javite ukoliko trebaju i verzije buildane za 32-bit/64-bit kao i za .N...Squiggle - A free open source LAN Messenger: Squiggle 3.2 (Development): NOTE: This is development release and not recommended for production use. This release is mainly for enabling extensibility and interoperability with other platforms. Support for plugins Support for extensions Communication layer and protocol is platform independent (ZeroMQ, ProtocolBuffers) Bug fixes New /invite command Edit the sent message Disable update check NOTE: This is development release and not recommended for production use.AcDown????? - AcDown Downloader Framework: AcDown????? v4.2: ??●AcDown??????????、??、??、???????。????，????，?????????????????????????。???????????Acfun、????(Bilibili)、??、??、YouTube、??、???、??????、SF????、????????????。 ●??????AcPlay?????，??????、????????????????。 ● AcDown??????????????????，????????????????????????????。 ● AcDown???????C#??，????.NET Framework 2.0??。?????"Acfun?????"。 ????32??64? Windows XP/Vista/7/8 ???? 32??64? ???Linux ????(1)????????Windows XP???，????????.NET Framework 2.0???(x86)，?????"?????????"??? (2)???????????Linux???，????????Mono?? ??2...PHPExcel: PHPExcel 1.7.8: See Change Log for details of the new features and bugfixes included in this release, and methods that are now deprecated. Note changes to the PDF Writer: tcPDF is no longer bundled with PHPExcel, but should be installed separately if you wish to use that 3rd-Party library with PHPExcel. Alternatively, you can choose to use mPDF or DomPDF as PDF Rendering libraries instead: PHPExcel now provides a configurable wrapper allowing you a choice of PDF renderer. See the documentation, or the PDF s...DirectX Tool Kit: October 12, 2012: October 12, 2012 Added PrimitiveBatch for drawing user primitives Debug object names for all D3D resources (for PIX and debug layer leak reporting)Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.70: Fixed issue described in discussion #399087: variable references within case values weren't getting resolved.GoogleMap Control: GoogleMap Control 6.1: Some important bug fixes and couple of new features were added. There are no major changes to the sample website. Source code could be downloaded from the Source Code section selecting branch release-6.1. Thus just builds of GoogleMap Control are issued here in this release. Update 14.Oct.2012 - Client side access fixed NuGet Package GoogleMap Control 6.1 NuGet Package FeaturesBounds property to provide ability to create a map by center and bounds as well; Setting in markup <artem:Goog...mojoPortal: 2.3.9.3: see release notes on mojoportal.com http://www.mojoportal.com/mojoportal-2393-released Note that we have separate deployment packages for .NET 3.5 and .NET 4.0, but we recommend you to use .NET 4, we will probably drop support for .NET 3.5 once .NET 4.5 is available The deployment package downloads on this page are pre-compiled and ready for production deployment, they contain no C# source code and are not intended for use in Visual Studio. To download the source code see getting the lates...D3 Loot Tracker: 1.5.4: Fixed a bug where the server ip was not logged properly in the stats file.Captcha MVC: Captcha Mvc 2.1.2: v 2.1.2: Fixed problem with serialization. Made all classes from a namespace Jetbrains.Annotaions as the internal. Added autocomplete attribute and autocorrect attribute for captcha input element. Minor changes. Updated: I'm added an example for this question. v 2.1.1: Fixed problem with serialization. Minor changes. v 2.1: Added support for storing captcha in the session or cookie. See the updated example. Updated example. Minor changes. v 2.0.1: Added support for a partial ...DotNetNuke® Community Edition CMS: 06.02.04: Major Highlights Fixed issue where the module printing function was only visible to administrators Fixed issue where pane level skinning was being assigned to a default container for any content pane Fixed issue when using password aging and FB / Google authentication Fixed issue that was causing the DateEditControl to not load the assigned value Fixed issue that stopped additional profile properties to be displayed in the member directory after modifying the template Fixed er...Database View-plug-ins Programming Helper: Database View-plug-ins 1.3: V1.3 added feature: Metadata Deployment. The download package consists of deployment SQL scripts. Run every scripts of all subdirectories in order (sort by name). "VPI" is the default schema name in the manifest, it can be changed to other name according to your enterprise database policy. Current release is for Oracle version (SQL Server version will be released later).Advanced DataGridView with Excel-like auto filter: 1.0.0.0: ?????? ??????New ProjectsAerTHe: Simple, test project about EntityFramework, NUnit, etc.BalanceManagerApp: BalanceManagerAppC++ Debugger Visualizers for VS2012: C++ Debugger Visualizers for Boost, wxWidgets, TinyXML, TinyXML2ClipReader: A Text-To-Speach reader that reads from the clipboard. Reads any text you copy to the clipboard. Similar idea to ReadPlease. Coursework 2.0 UGC Site: University of Hertfordshire coursework project to develop a Web 2.0-style UGC website. DavesinitialcourseworkcalculatorinVS: Basic calculator for assignment 1DL_Assignment 1: This project forms Task 1 of Assignment 1 for 7COM0207. The requirement is that a user can enter 2 numbers and the sum of the numbes is displayed. Document Storage: This project is intended to act as a learning exercise for the participants. gillsassignment1: This is task 1 for assignment 1 which adds 2 numbers and displays the result.gillstestproject: This is my first little test.Iconator for Microsoft Dynamics CRM 2011: This application ease the customization of custom entities icons in Microsoft Dynamics CRM 2011.Infopath 2010 Web Signature Capture: A simple method of adding signature capture to InfoPath Browser enabled forms. KennyWorld: Kenny's blog based on BLogEngine.netMirus - Advanced Open Source Operating System: Mirus is a new, advanced, open source operating system written in C# using the Cosmos toolkit aiming for POSIX compatibility, ease of use, and innovation.Morgado Finance: Test of Finance ManagementMPF for Projects - Visual Studio 2012: A community project containing the source code and tests of a library for creating project system plug-ins for Visual Studio 2012 using C#.OpenWeb: OpenWeb project by Deigo Stefanon [*/*P1 Port monitoring with Netduino Plus: This program reads the Dutch electricity meter P1 port messages and publishes the information to Cosm and ThingSpeak for monitoring.Powerless View: Proof of concept application for hosting the Power View Silverlight application outside of a SharePoint and Reporting Services environment.RAM Drive: A Windows Service that copies an existing Virtual Hard Disk in memory, then mounts it as a disk giving the ability to use your RAM as a super-fast drive.Roderick Vella's Interactive Learning: Web Scripting and Content CreationSaveDouban: ?????????????????，????.NetFramework3.5?????ScriptEase for Microsoft Dynamics CRM 2011: Utility to synchronize your Microsoft Dynamics CRM 2011 JavaScripts with your files on your local hard-drive.T.REST: T.REST - a framework for testing REST ressourcesVisual Leak Detector Performance Test: Tests for Visual Leak Detector for Visual C++ 2008/2010/2012 [url:http://vld.codeplex.com/]???????: ????????????????。?????????????。 ??url??，??????

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• Five development tools I can't live without

  - by bconlon

  When applying to join Geeks with Blogs I had to specify the development tools I use every day. That got me thinking, it's taken a long time to whittle my tools of choice down to the selection I use, so it might be worth sharing. Before I begin, I appreciate we all have our preferred development tools, but these are the ones that work for me. Microsoft Visual Studio Microsoft Visual Studio has been my development tool of choice for more years than I care to remember. I first used this when it was Visual C++ 1.5 (hats off to those who started on 1.0) and by 2.2 it had everything I needed from a C++ IDE. Versions 4 and 5 followed and if I had to guess I would expect more Windows applications are written in VC++ 6 and VB6 than any other language. Then came the not so great versions Visual Studio .Net 2002 (7.0) and 2003 (7.1). If I'm honest I was still using v6. 2005 was better and 2008 was simply brilliant. Everything worked, the compiler was super fast and I was happy again...then came 2010...oh dear. 2010 is a big step backwards for me. It's not encouraging for my upcoming WPF exploits that 2010 is fronted in WPF technology, with the forever growing Find/Replace dialog, the issues with C++ intellisense, and the buggy debugger. That said it is still my tool of choice but I hope they sort the issue in SP1. I've tried other IDEs like Visual Age and Eclipse, but for me Visual Studio is the best. A really great tool. Liquid XML Studio XML development is a tricky business. The W3C standards are often difficult to get to the bottom of so it's great to have a graphical tool to help. I first used Liquid Technologies 5 or 6 years back when I needed to process XML data in C++. Their excellent XML Data Binding tool has an easy to use Wizard UI (as compared to Castor or JAXB command line tools) and allows you to generate code from an XML Schema. So instead of having to deal with untyped nodes like with a DOM parser, instead you get an Object Model providing a custom API in C++, C#, VB etc. More recently they developed a graphical XML IDE with XML Editor, XSLT, XQuery debugger and other XML tools. So now I can develop an XML Schema graphically, click a button to generate a Sample XML document, and click another button to run the Wizard to generate code including a Sample Application that will then load my Sample XML document into the generated object model. This is a very cool toolset. Note: XML Data Binding is nothing to do with WPF Data Binding, but I hope to cover both in more detail another time. .Net Reflector Note: I've just noticed that starting form the end of February 2011 this will no longer be a free tool !! .Net Reflector turns .Net byte code back into C# source code. But how can it work this magic? Well the clue is in the name, it uses reflection to inspect a compiled .Net assembly. The assembly is compiled to byte code, it doesn't get compiled to native machine code until its needed using a just-in-time (JIT) compiler. The byte code still has all of the information needed to see classes, variables. methods and properties, so reflector gathers this information and puts it in a handy tree. I have used .Net Reflector for years in order to understand what the .Net Framework is doing as it sometimes has undocumented, quirky features. This really has been invaluable in certain instances and I cannot praise enough kudos on the original developer Lutz Roeder. Smart Assembly In order to stop nosy geeks looking at our code using a tool like .Net Reflector, we need to obfuscate (mess up) the byte code. Smart Assembly is a tool that does this. Again I have used this for a long time. It is very quick and easy to use. Another excellent tool. Coincidentally, .Net Reflector and Smart Assembly are now both owned by Red Gate. Again kudos goes to the original developer Jean-Sebastien Lange. TortoiseSVN SVN (Apache Subversion) is a Source Control System developed as an open source project. TortoiseSVN is a graphical UI wrapper over SVN that hooks into Windows Explorer to enable files to be Updated, Committed, Merged etc. from the right click menu. This is an essential tool for keeping my hard work safe! Many years ago I used Microsoft Source Safe and I disliked CVS type systems. But TortoiseSVN is simply the best source control tool I have ever used. --- So there you have it, my top 5 development tools that I use (nearly) every day and have helped to make my working life a little easier. I'm sure there are other great tools that I wish I used but have never heard of, but if you have not used any of the above, I would suggest you check them out as they are all very, very cool products. #

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• Career guidance/advice for Junior-level Software Engineer [closed]

  - by John Do

  I have quite a few questions on my mind, so please bare with me. Please don't feel obligated to answer all of them, any as you choose will do. I'd appreciate if you could share some insight on any of these. Before I begin, some context: I currently have almost two years of professional experience as a Software Engineer, mainly developing software in Java. At this point, I feel that I have reached the peak in my career growth at the current company I am at and therefore I am looking for a new job, ideally again, as a Software Engineer. I have been interviewing for the past few months casually but have not had luck with companies I have a passion for. So, in no particular order - 1) In general, what are your thoughts on having graduate degrees in CS / Software Engineering. How much does it influence a salary increase, and do you think it's beneficial when working on real-world problems? I get the sense that a graduate degree in the field is trivial unless you really have a passion for research. 2) In general, in professional practice, how often had you have to write your own data structures and "complex" algorithms from scratch? In my own work, I have found myself relying mainly on third-party frameworks and the Java standard library to implement solutions as per business requirements. What are your thoughts on this? 3) In terms of resume, I feel the most ambivalent here. I want to be able to "blemish" my resume to a certain extent so that it stands out from others', but at the same time I do not want to over-exagerate my abilities. How do you strike a balance here? For example: I say that I am proficient in Java with data structures and algorithms. This is obviously a subjective and relative statement. I've taken the classes in my undergrad, and I've applied it in my work experience. What I feel as "prociency" can be seen as junior-level to others. How do you know what to say? Most of the time, recruiters (with no technical background) will be looking for keywords that stand out. This leads me to my next question (4). 4) Just from interviewing for the past few months (and getting plenty of rejections), I've come to realize that I may not be as proficient in data structures and algorithms as I thought I was. Do you think it's a good idea to remove the "proficient in java/data structure and algorithms"? I feel that being too hoenst on the resume will impede me from scoring opportunities to even have an interview with top-notch companies. What are your thoughts? 5) What is the absolute "must-have" knowledge going into a technical interview? I've been practicing several algorithmic and data sturcture problems now, and I feel that my abilities to solve arbitrary problems efficiently has not gotten significantly better. Do you think these abilities are something innate - it's either you have in you, or you don't? How can you teach yourself to learn, if you will? 6) How easy is it to go from industry/function to the next? I work mainly with backend technologies and I'm now interested in working with the frontend, i.e javascript,jquery,php or even mobile development. In your own experience, how did you not get pidgeon holed in your career? I feel that the choices you make now ultimately decide your future. As cliche as it sounds, I think it may be true. Here's what I mean: you've worked mainly as a backend engineer, people are interested in you doing the same thing since you've already accumulated experience in that function. How do get experience in a new function if people won't accept you because you don't already have it? It's a catch 22, you see... Are side projects the only real way to help you move from one function to another that you're truly interested in? For example: I could start writing my own mobile applications, even though I've worked mainly on the backend. Thanks so much for the long read. As a relatively new engineer to the real world, I am very humble and would like those who are experienced to shed some light. Thank you so much.

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• yield – Just yet another sexy c# keyword?

  - by George Mamaladze

  yield (see NSDN c# reference) operator came I guess with .NET 2.0 and I my feeling is that it’s not as wide used as it could (or should) be.   I am not going to talk here about necessarity and advantages of using iterator pattern when accessing custom sequences (just google it).   Let’s look at it from the clean code point of view. Let's see if it really helps us to keep our code understandable, reusable and testable.   Let’s say we want to iterate a tree and do something with it’s nodes, for instance calculate a sum of their values. So the most elegant way would be to build a recursive method performing a classic depth traversal returning the sum.           private int CalculateTreeSum(Node top)         {             int sumOfChildNodes = 0;             foreach (Node childNode in top.ChildNodes)             {                 sumOfChildNodes += CalculateTreeSum(childNode);             }             return top.Value + sumOfChildNodes;         }     “Do One Thing” Nevertheless it violates one of the most important rules “Do One Thing”. Our  method CalculateTreeSum does two things at the same time. It travels inside the tree and performs some computation – in this case calculates sum. Doing two things in one method is definitely a bad thing because of several reasons: ·          Understandability: Readability / refactoring ·          Reuseability: when overriding - no chance to override computation without copying iteration code and vice versa. ·          Testability: you are not able to test computation without constructing the tree and you are not able to test correctness of tree iteration.   I want to spend some more words on this last issue. How do you test the method CalculateTreeSum when it contains two in one: computation & iteration? The only chance is to construct a test tree and assert the result of the method call, in our case the sum against our expectation. And if the test fails you do not know wether was the computation algorithm wrong or was that the iteration? At the end to top it all off I tell you: according to Murphy’s Law the iteration will have a bug as well as the calculation. Both bugs in a combination will cause the sum to be accidentally exactly the same you expect and the test will PASS. J   Ok let’s use yield! That’s why it is generally a very good idea not to mix but isolate “things”. Ok let’s use yield!           private int CalculateTreeSumClean(Node top)         {             IEnumerable<Node> treeNodes = GetTreeNodes(top);             return CalculateSum(treeNodes);         }             private int CalculateSum(IEnumerable<Node> nodes)         {             int sumOfNodes = 0;             foreach (Node node in nodes)             {                 sumOfNodes += node.Value;             }             return sumOfNodes;         }           private IEnumerable<Node> GetTreeNodes(Node top)         {             yield return top;             foreach (Node childNode in top.ChildNodes)             {                 foreach (Node currentNode in GetTreeNodes(childNode))                 {                     yield return currentNode;                 }             }         }   Two methods does not know anything about each other. One contains calculation logic another jut the iteration logic. You can relpace the tree iteration algorithm from depth traversal to breath trevaersal or use stack or visitor pattern instead of recursion. This will not influence your calculation logic. And vice versa you can relace the sum with product or do whatever you want with node values, the calculateion algorithm is not aware of beeng working on some tree or graph.  How about not using yield? Now let’s ask the question – what if we do not have yield operator? The brief look at the generated code gives us an answer. The compiler generates a 150 lines long class to implement the iteration logic.       [CompilerGenerated]     private sealed class <GetTreeNodes>d__0 : IEnumerable<Node>, IEnumerable, IEnumerator<Node>, IEnumerator, IDisposable     {         ...        150 Lines of generated code        ...     }   Often we compromise code readability, cleanness, testability, etc. – to reduce number of classes, code lines, keystrokes and mouse clicks. This is the human nature - we are lazy. Knowing and using such a sexy construct like yield, allows us to be lazy, write very few lines of code and at the same time stay clean and do one thing in a method. That's why I generally welcome using staff like that.   Note: The above used recursive depth traversal algorithm is possibly the compact one but not the best one from the performance and memory utilization point of view. It was taken to emphasize on other primary aspects of this post.

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• CodePlex Daily Summary for Friday, October 12, 2012

  CodePlex Daily Summary for Friday, October 12, 2012Popular ReleasesHyperCrunch Druid: HyperCrunch Druid 1.0.2102: For all documentation and feedback, visit http://druid.hypercrunch.com.GoogleMap Control: GoogleMap Control 6.1: Some important bug fixes and couple of new features were added. There are no major changes to the sample website. Source code could be downloaded from the Source Code section selecting branch release-6.1. Thus just builds of GoogleMap Control are issued here in this release. NuGet Package GoogleMap Control 6.1 NuGet Package FeaturesBounds property to provide ability to create a map by center and bounds as well; Setting in markup <artem:GoogleMap ID="GoogleMap1" runat="server" MapType="HY...Bundle Transformer - a modular extension for ASP.NET Web Optimization Framework: Bundle Transformer 1.6.5: Version: 1.6.5 Published: 10/12/2012 In the configuration elements css and js added the usePreMinifiedFiles attribute, which enables/disables usage of pre-minified files; Added translator-adapter, which produces translation of TypeScript-code to JS-code; In BundleTransformer.MicrosoftAjax added support of the Microsoft Ajax Minifier 4.69; In BundleTransformer.Yui added support of the YUI Compressor for .NET 2.1.0.0; In BundleTransformer.Csso added support of the CSSO version 1.3.4. ...OrgCharts for SharePoint: OrgChart web part for SharePoint: Key features: • Central License management so no need to remember the license key details when adding to pages. • Builtin-asp.net caching for high performing loading of the Org Chart. • Create Org Chart from SharePoint list data OR SQL server queries. • Multi-level drill through • Use SharePoint lists or SQL Data as datasource • Support node level Images. {Example: Peoples my site photos} • AJAX enabled for fast client side processing • Optionally set the TAB field for an Auto-generated TAB i...mojoPortal: 2.3.9.3: see release notes on mojoportal.com http://www.mojoportal.com/mojoportal-2393-released Note that we have separate deployment packages for .NET 3.5 and .NET 4.0, but we recommend you to use .NET 4, we will probably drop support for .NET 3.5 once .NET 4.5 is available The deployment package downloads on this page are pre-compiled and ready for production deployment, they contain no C# source code and are not intended for use in Visual Studio. To download the source code see getting the lates...OstrivDB: OstrivDB 0.1: - Storage configuration: objects serialization (Xml, Json), storage file compressing, data block size. - Caching for Select queries. - Indexing. - Batch of queries. - No special query language (LINQ used). - Integrated sorting and paging. - Multithreaded data processing.D3 Loot Tracker: 1.5.4: Fixed a bug where the server ip was not logged properly in the stats file.Captcha MVC: Captcha Mvc 2.1.2: v 2.1.2: Fixed problem with serialization. Made all classes from a namespace Jetbrains.Annotaions as the internal. Added autocomplete attribute and autocorrect attribute for captcha input element. Minor changes. v 2.1.1: Fixed problem with serialization. Minor changes. v 2.1: Added support for storing captcha in the session or cookie. See the updated example. Updated example. Minor changes. v 2.0.1: Added support for a partial captcha. Now you can easily customize the layout, s...DotNetNuke® Community Edition CMS: 06.02.04: Major Highlights Fixed issue where the module printing function was only visible to administrators Fixed issue where pane level skinning was being assigned to a default container for any content pane Fixed issue when using password aging and FB / Google authentication Fixed issue that was causing the DateEditControl to not load the assigned value Fixed issue that stopped additional profile properties to be displayed in the member directory after modifying the template Fixed er...Advanced DataGridView with Excel-like auto filter: 1.0.0.0: ?????? ??????Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.69: Fix for issue #18766: build task should not build the output if it's newer than all the input files. Fix for Issue #18764: build taks -res switch not working. update build task to concatenate input source and then minify, rather than minify and then concatenate. include resource string-replacement root name in the assumed globals list. Stop replacing new Date().getTime() with +new Date -- the latter is smaller, but turns out it executes up to 45% slower. add CSS support for single-...WinRT XAML Toolkit: WinRT XAML Toolkit - 1.3.3: WinRT XAML Toolkit based on the Windows 8 RTM SDK. Download the latest source from the SOURCE CODE page. For compiled version use NuGet. You can add it to your project in Visual Studio by going to View/Other Windows/Package Manager Console and entering: PM> Install-Package winrtxamltoolkit Features Attachable Behaviors AwaitableUI extensions Controls Converters Debugging helpers Extension methods Imaging helpers IO helpers VisualTree helpers Samples Recent changes NOTE:...VidCoder: 1.4.4 Beta: Fixed inability to create new presets with "Save As".MCEBuddy 2.x: MCEBuddy 2.3.2: Changelog for 2.3.2 (32bit and 64bit) 1. Added support for generating XBMC XML NFO files for files in the conversion queue (store it along with the source video with source video name.nfo). Right click on the file in queue and select generate XML 2. UI bugifx, start and end trim box locations interchanged 3. Added support for removing commercials from non DVRMS/WTV files (MP4, AVI etc) 4. Now checking for Firewall port status before enabling (might help with some firewall problems) 5. User In...Sandcastle Help File Builder: SHFB v1.9.5.0 with Visual Studio Package: General InformationIMPORTANT: On some systems, the content of the ZIP file is blocked and the installer may fail to run. Before extracting it, right click on the ZIP file, select Properties, and click on the Unblock button if it is present in the lower right corner of the General tab in the properties dialog. This release supports the Sandcastle October 2012 Release (v2.7.1.0). It includes full support for generating, installing, and removing MS Help Viewer files. This new release suppor...ClosedXML - The easy way to OpenXML: ClosedXML 0.68.0: ClosedXML now resolves formulas! Yes it finally happened. If you call cell.Value and it has a formula the library will try to evaluate the formula and give you the result. For example: var wb = new XLWorkbook(); var ws = wb.AddWorksheet("Sheet1"); ws.Cell("A1").SetValue(1).CellBelow().SetValue(1); ws.Cell("B1").SetValue(1).CellBelow().SetValue(1); ws.Cell("C1").FormulaA1 = "\"The total value is: \" & SUM(A1:B2)"; var...Json.NET: Json.NET 4.5 Release 10: New feature - Added Portable build to NuGet package New feature - Added GetValue and TryGetValue with StringComparison to JObject Change - Improved duplicate object reference id error message Fix - Fixed error when comparing empty JObjects Fix - Fixed SecAnnotate warnings Fix - Fixed error when comparing DateTime JValue with a DateTimeOffset JValue Fix - Fixed serializer sometimes not using DateParseHandling setting Fix - Fixed error in JsonWriter.WriteToken when writing a DateT...Readable Passphrase Generator: KeePass Plugin 0.7.2: Changes: Tested against KeePass 2.20.1 Tested under Ubuntu 12.10 (and KeePass 2.20) Added GenerateAsUtf8 method returning the encrypted passphrase as a UTF8 byte array.JSLint for Visual Studio 2010: 1.4.2: 1.4.2patterns & practices: Prism: Prism for .NET 4.5: This is a release does not include any functionality changes over Prism 4.1 Desktop. These assemblies target .NET 4.5. These assemblies also were compiled against updated dependencies: Unity 3.0 and Common Service Locator (Portable Class Library).New ProjectsATM Stimulate Using WCF Service: This project is my homework Basic Events: Basic Events makes it easier for developers to use out of the box events with basic properties in their eventargs like string message and datetime.BCCP-DEX: sumary not avaibleBing Maps TypeScript Declarations: Unofficial TypeScript declarations for the Bing Maps v7 AJAX Control.CodePlex Practice: Testing CodePlexDepIC: Dependency Injection Container with a very simple API.DNN TaskManger: This is the a project build with the DotNetNuke task manager tutorial videos series.Document Importer For SharePoint: Quickly import large volumes of documents into SharePoint document libraries using an effective user interface.Drop Me!!: cOMING SOON...wORKING ON THISGesPro: PFE de fin de BAC MB MLGL2DX (OpenGL to DirectX Wrapper Library): GL2DX is a wrapper library that allows you to build your OpenGL app for WinRT.MoControls - XNA 4 GUI Controls Library: XNA 4 GUI Controls Library aimed to simplify porting of a XNA 4.0 GUI interface to various platforms.Morph implementation in Delphi: Morph Protocol implementation written in Delphi XE3. Morph is a very powerful application level protocol. For more about Morph, go to http://morph.codeplex.com/Musicallis: Projeto da disciplina de Técnicas de Programação Aplicada II da Universidade Presbiteriana Mackenzie - SP.NHook - A debugger API for your hooking projects: A debugger API for your hooking projectsOperation Timber System: This is a Timber system aimed at merchants/wholesalers/Mills. It is only in design phase.Oryon .Net Extension Methods Library: This project contains a lot of useful extension methods for .Net Applications.OstrivDB: OstrivDB is an embedded NoSQL database engine.Outreach02: A research project for website development.PARCIAL-CP-2012: Proyecto De Calidad y Pruebas de Software - Examen ParcialProject13261011: dfdsfProject13271011: 11project-3D-fabien: C# project 3D IN4M12 -->http://www.esiee.fr/~mustafan/IN4M12-13/Pulsar Programming Language: Pulsar, is a free open source programming language alternative to Assembly. Create your dream Operating System without using Assembly, or C#, or C++!Scoot: A rowing club management application.Sfaar Bytex: an hexadecimal file readerSSIS RAW File Viewer: SSIS 2008 RAW file viewer.testddgit1011201201: ttesttom10112012tfs02: fdsf fsd???WindowsPhone???: ???Windows Phone??????www.yidingcan.com?????。??????、??

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• Stumbling Through: Visual Studio 2010 (Part II)

  I would now like to expand a little on what I stumbled through in part I of my Visual Studio 2010 post and touch on a few other features of VS 2010.  Specifically, I want to generate some code based off of an Entity Framework model and tie it up to an actual data source.  Im not going to take the easy way and tie to a SQL Server data source, though, I will tie it to an XML data file instead.  Why?  Well, why not?  This is purely for learning, there are probably much better ways to get strongly-typed classes around XML but it will force us to go down a path less travelled and maybe learn a few things along the way.  Once we get this XML data and the means to interact with it, I will revisit data binding to this data in a WPF form and see if I cant get reading, adding, deleting, and updating working smoothly with minimal code.  To begin, I will use what was learned in the first part of this blog topic and draw out a data model for the MFL (My Football League) - I dont want the NFL to come down and sue me for using their name in this totally football-related article.  The data model looks as follows, with Teams having Players, and Players having a position and statistics for each season they played: Note that when making the associations between these entities, I was given the option to create the foreign key but I only chose to select this option for the association between Player and Position.  The reason for this is that I am picturing the XML that will contain this data to look somewhat like this: <MFL> <Position/> <Position/> <Position/> <Team>     <Player>         <Statistic/>     </Player> </Team> </MFL> Statistic will be under its associated Player node, and Player will be under its associated Team node no need to have an Id to reference it if we know it will always fall under its parent.  Position, however, is more of a lookup value that will not have any hierarchical relationship to the player.  In fact, the Position data itself may be in a completely different xml file (something Id like to play around with), so in any case, a player will need to reference the position by its Id. So now that we have a simple data model laid out, I would like to generate two things based on it:  A class for each entity with properties corresponding to each entity property An IO class with methods to get data for each entity, either all instances, by Id or by parent. Now my experience with code generation in the past has consisted of writing up little apps that use the code dom directly to regenerate code on demand (or using tools like CodeSmith).  Surely, there has got to be a more fun way to do this given that we are using the Entity Framework which already has built-in code generation for SQL Server support.  Lets start with that built-in stuff to give us a base to work off of.  Right click anywhere in the canvas of our model and select Add Code Generation Item: So just adding that code item seemed to do quite a bit towards what I was intending: It apparently generated a class for each entity, but also a whole ton more.  I mean a TON more.  Way too much complicated code was generated now that code is likely to be a black box anyway so it shouldnt matter, but we need to understand how to make this work the way we want it to work, so lets get ready to do some stumbling through that text template (tt) file. When I open the .tt file that was generated, right off the bat I realize there is going to be trouble there is no color coding, no intellisense no nothing!  That is going to make stumbling through more like groping blindly in the dark while handcuffed and hopping on one foot, which was one of the alternate titles I was considering for this blog.  Thankfully, the community comes to my rescue and I wont have to cast my mind back to the glory days of coding in VI (look it up, kids).  Using the Extension Manager (Available under the Tools menu), I did a quick search for tt editor in the Online Gallery and quickly found the Tangible T4 Editor: Downloading and installing this was a breeze, and after doing so I got some color coding and intellisense while editing the tt files.  If you will be doing any customizing of tt files, I highly recommend installing this extension.  Next, well see if that is enough help for us to tweak that tt file to do the kind of code generation that we wantDid 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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• Modularity through HTTP

  - by Michael Williamson

  As programmers, we strive for modularity in the code we write. We hope that splitting the problem up makes it easier to solve, and allows us to reuse parts of our code in other applications. Object-orientation is the most obvious of many attempts to get us closer to this ideal, and yet one of the most successful approaches is almost accidental: the web. Programming languages provide us with functions and classes, and plenty of other ways to modularize our code. This allows us to take our large problem, split it into small parts, and solve those small parts without having to worry about the whole. It also makes it easier to reason about our code. So far, so good, but now that we’ve written our small, independent module, for example to send out e-mails to my customers, we’d like to reuse it in another application. By creating DLLs, JARs or our platform’s package container of choice, we can do just that – provided our new application is on the same platform. Want to use a Java library from C#? Well, good luck – it might be possible, but it’s not going to be smooth sailing. Even if a library exists, it doesn’t mean that using it going to be a pleasant experience. Say I want to use Java to write out an XML document to an output stream. You’d imagine this would be a simple one-liner. You’d be wrong: import org.w3c.dom.*; import java.io.*; import javax.xml.transform.*; import javax.xml.transform.dom.*; import javax.xml.transform.stream.*; private static final void writeDoc(Document doc, OutputStream out) throws IOException { try { Transformer t = TransformerFactory.newInstance().newTransformer(); t.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM, doc.getDoctype().getSystemId()); t.transform(new DOMSource(doc), new StreamResult(out)); } catch (TransformerException e) { throw new AssertionError(e); // Can't happen! } } Most of the time, there is a good chance somebody else has written the code before, but if nobody can understand the interface to that code, nobody’s going to use it. The result is that most of the code we write is just a variation on a theme. Despite our best efforts, we’ve fallen a little short of our ideal, but the web brings us closer. If we want to send e-mails to our customers, we could write an e-mail-sending library. More likely, we’d use an existing one for our language. Even then, we probably wouldn’t have niceties like A/B testing or DKIM signing. Alternatively, we could just fire some HTTP requests at MailChimp, and get a whole slew of features without getting anywhere near the code that implements them. The web is inherently language agnostic. So long as your language can send and receive text over HTTP, and probably parse some JSON, you’re about as well equipped as anybody. Instead of building libraries for a specific language, we can build a service that almost every language can reuse. The text-based nature of HTTP also helps to limit the complexity of the API. As SOAP will attest, you can still make a horrible mess using HTTP, but at least it is an obvious horrible mess. Complex data structures are tedious to marshal to and from text, providing a strong incentive to keep things simple. By contrast, spotting the complexities in a class hierarchy is often not as easy. HTTP doesn’t solve every problem. It probably isn’t such a good idea to use it inside an inner loop that’s executed thousands of times per second. What’s more, the HTTP approach might introduce some new problems. We often need to add a thin shim to each application that we wish to communicate over HTTP. For instance, we might need to write a small plugin in PHP if we want to integrate WordPress into our system. Suddenly, instead of a system written in one language, we’re maintaining a system with several distinct languages and platforms. Even then, we should strive to avoid re-implementing the same old thing. As programmers, we consistently underestimate both the cost of building a system and the ongoing maintenance. If we allow ourselves to integrate existing applications, even if they’re in unfamiliar languages, we save ourselves those development and maintenance costs, as well as being able to pick the best solution for our problem. Thanks to the web, HTTP is often the easiest way to get there.

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