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  • Code generating SOAP Web Service Proxy objects yourself - C#/.NET 3.5/T4

    - by tyndall
    Is there a framework or code already available that will give me more control over the code that gets generated based off my web references? I'm working at a new company. And the Web Services Proxies are all self contained in their own assembly. I would really rather generate this whole project. Every time they change something on the Services-side (Java) the WSDL references have to be dropped and re-added. (I can't figure out what those guys are doing on their end that messes with the WSDL bad enough that this needs to be done so much) Their are 10 of these references. I'd rather codegen the whole thing at compile time. Every time. What are my options?

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  • Netbeans source code formatting

    - by lucky
    I am Netbeans user for PHP. I have installed Netbeans IDE 6.8. Everything is working well. There is an option in SOURCE -- FORMAT. This action formats the code properly. It is quite handy. Unfortunately, this functionality is not working for me. Whenever some php code comes in between, it additionally adding some empty rows in between and making it more untidy. Can you please help to set up the same functionality. Restore the settings to default.

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  • Zero code coverage with cobertura 1.9.2 but tests are working

    - by eraonel
    I run the code coverage target: <junit fork="yes" dir="${basedir}" failureProperty="test.failed"> <!-- Note the classpath order: instrumented classes are before the original (uninstrumented) classes. This is important. --> <classpath path="${instrumented.dir}" /> <classpath path="${classes.dir}" /> <classpath refid="classpath" /> <!-- The instrumented classes reference classes used by the Cobertura runtime, so Cobertura and its dependencies must be on your classpath. --> <classpath refid="cobertura.classpath" /> <formatter type="xml" /> <!--<test name="${testcase}" todir="${reports.xml.dir}" if="testcase" />--> <batchtest fork="yes" todir="${reports.xml.dir}"> <fileset dir="${classes.dir}"> <include name="**/generated/AllTests.class" /> </fileset> </batchtest> </junit> <junitreport todir="${reports.xml.dir}"> <fileset dir="${reports.xml.dir}"> <include name="TEST-*.xml" /> </fileset> <report format="frames" todir="${reports.html.dir}" /> </junitreport> Then I get the following output ( when using fork="true"): java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at net.sourceforge.cobertura.util.FileLocker.lock(FileLocker.java:124) at net.sourceforge.cobertura.coveragedata.ProjectData.saveGlobalProjectData(ProjectData.java:331) at net.sourceforge.cobertura.coveragedata.SaveTimer.run(SaveTimer.java:31) at java.lang.Thread.run(Thread.java:595) Caused by: java.io.IOException: No locks available at sun.nio.ch.FileChannelImpl.lock0(Native Method) at sun.nio.ch.FileChannelImpl.lock(FileChannelImpl.java:784) at java.nio.channels.FileChannel.lock(FileChannel.java:865) ... 8 more --------------------------------------- Unable to get lock on /vobs/rnc/rrt/roam2/roamSs/RoamMao_swb/RoamMao_bldu/ant_build/cobertura.ser.lock: null This is known to happen on Linux kernel 2.6.20. Make sure cobertura.jar is in the root classpath of the jvm process running the instrumented code. If the instrumented code is running in a web server, this means cobertura.jar should be in the web server's lib directory. Don't put multiple copies of cobertura.jar in different WEB-INF/lib directories. Only one classloader should load cobertura. It should be the root classloader. I am using Ant 1.7.0 and cobertura 1.9.2. Any ideas why there is no coverage? Test run ok as I see in my target. I have tried to switch java versions ( 1.5.0_06 and 1.6.0_10) but no difference.

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  • Automated Java to Scala source code conversion?

    - by Alex R
    (Yes I know I can call Java code from Scala; but that is pointless; I want to DELETE the Java code, not keep it around and have to look at it and maintain it forever!) Are there any utilities out there to convert Java source to Scala source? I believe theoretically it should be possible to accomplish with minimal lossage. I have found this but it seems inactive, probably buggy/incomplete... http://sourceforge.net/projects/java2scala/ Any alternatives?

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  • Lines-of-code counting for many C# solutions

    - by Eric
    I am currently researching a solution for counting lines of code in C#. I pretty much need a combination of the following two tools: http://richnewman.wordpress.com/2007/07/01/c-and-vbnet-line-count-utility/ http://www.locmetrics.com/index.html My problem is that I need to recursively scan a folder containing a lot of visual studio solutions. So can't really use the first tool without any major work on its code, as it's only able to scan a single solution at a time. But I also need to split the results for each solution, preferably even the contained projects. This disqualifies the second tool I found. I also found NDepend which suffers from the same problem. Do you know of any free tools that do what I need? I am unable to find anything suitable.

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  • Is Lightweight Code Generation (LCG) dead?

    - by Greg Beech
    In the .NET 2.0-3.5 frameworks, LCG (aka the DynamicMethod class) was a decent way to emit lightweight methods at runtime when no class structure was needed to support them. In .NET 4.0, expression trees now support statements and blocks, and as such appear to provide sufficient functionality to build just about any functionality you could require from such a method, and can be constructed in a much easier and safer way than directly emitting CIL op-codes. (This statement is borne from today's experimentation of converting some of our most complex LCG code to use expression tree building and compilation instead.) So is there any reason why one would use LCG in any new code? Is there anything it can do that expression trees cannot? Or is it now a 'dead' piece of functionality?

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  • Django - Tips to avoid repeating code in views

    - by D Roddis
    I'm moving from a PHP background into Django development via python, mostly for the sake of tackling a MVC (or MVT) that I feel makes the most sense, although in this pattern I've started to notice a lot of repeated code in my views. For example, when logged in I have information regarding the user that I would like to appear on every page, although when using render_to_response and in every view this is required I have to grab the information and pass it to the render_to_response function. I'm wondering what would be the most efficient way to cut down on the duplicate code which would in essence be required in all views in a particular app. Thanks in advance.

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  • Facebook Feed Dialog Returns API Error Code: 191

    - by Kris
    In my Facebook App I'll always get the following error : An error occurred. Please try again later. API Error Code: 191 API Error Description: The specified URL is not owned by the application Error Message: redirect_uri is not owned by the application. I just want to feed a post via button my code is function postToFeed() { // calling the API ... var obj = { method: 'feed', link: 'https://mydomain.com/', picture: 'https://mydomain.com/img/feed.png', name: 'BLABLADialog', caption: 'UeberschriftBLABLA', description: 'DescriptionBLABLA', show_error: true }; function callback(response) { document.getElementById('msg').innerHTML = "Post ID: " + response['post_id']; } FB.ui(obj, callback); } my Canvas-URL is "http://mydomain.com/" my Secure Canvas-URL is "https://mydomain.com/" my Tab-URL is "https://mydomain.com/tab.php" my Secure Tab-URL is "https://mydomain.com/tab.php" my Website with Facebook Login SITE URL is "https://mydomain.com/" so what I am doing wrong ?

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  • Any Code Review Communities out there?

    - by willcodejavaforfood
    After reading this post I had a look around for 'code review' communities, but I did not really find one. There were a few but they were usually for a very specific technology and not just a programming language specific one. Never really thought of it before, but there sure is a lot of code out there that could benefit from a review. Not only is it a really good way to pick up new skills from your peers (or superiors), but it will also improve quality. Does anyone know of one?

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  • Need help converting Ruby code to php code

    - by newprog
    Yesterday I posted this queston. Today I found the code which I need but written in Ruby. Some parts of code I have understood (I don't know Ruby) but there is one part that I can't. I think people who know ruby and php can help me understand this code. def do_create(image) # Clear any old info in case of a re-submit FIELDS_TO_CLEAR.each { |field| image.send(field+'=', nil) } image.save # Compose request vm_params = Hash.new # Submitting a file in ruby requires opening it and then reading the contents into the post body file = File.open(image.filename_in, "rb") # Populate the parameters and compute the signature # Normally you would do this in a subroutine - for maximum clarity all # parameters are explicitly spelled out here. vm_params["image"] = file # Contents will be read by the multipart object created below vm_params["image_checksum"] = image.image_checksum vm_params["start_job"] = 'vectorize' vm_params["image_type"] = image.image_type if image.image_type != 'none' vm_params["image_complexity"] = image.image_complexity if image.image_complexity != 'none' vm_params["image_num_colors"] = image.image_num_colors if image.image_num_colors != '' vm_params["image_colors"] = image.image_colors if image.image_colors != '' vm_params["expire_at"] = image.expire_at if image.expire_at != '' vm_params["licensee_id"] = DEVELOPER_ID #in php it's like this $vm_params["sequence_number"] = -rand(100000000);????? vm_params["sequence_number"] = Kernel.rand(1000000000) # Use a negative value to force an error when calling the test server vm_params["timestamp"] = Time.new.utc.httpdate string_to_sign = CREATE_URL + # Start out with the URL being called... #vm_params["image"].to_s + # ... don't include the file per se - use the checksum instead vm_params["image_checksum"].to_s + # ... then include all regular parameters vm_params["start_job"].to_s + vm_params["image_type"].to_s + vm_params["image_complexity"].to_s + # (nil.to_s => '', so this is fine for vm_params we don't use) vm_params["image_num_colors"].to_s + vm_params["image_colors"].to_s + vm_params["expire_at"].to_s + vm_params["licensee_id"].to_s + # ... then do all the security parameters vm_params["sequence_number"].to_s + vm_params["timestamp"].to_s vm_params["signature"] = sign(string_to_sign) #no problem # Workaround class for handling multipart posts mp = Multipart::MultipartPost.new query, headers = mp.prepare_query(vm_params) # Handles the file parameter in a special way (see /lib/multipart.rb) file.close # mp has read the contents, we can close the file now response = post_form(URI.parse(CREATE_URL), query, headers) logger.info(response.body) response_hash = ActiveSupport::JSON.decode(response.body) # Decode the JSON response string ##I have understood below def sign(string_to_sign) #logger.info("String to sign: '#{string_to_sign}'") Base64.encode64(HMAC::SHA1.digest(DEVELOPER_KEY, string_to_sign)) end # Within Multipart modul I have this: class MultipartPost BOUNDARY = 'tarsiers-rule0000' HEADER = {"Content-type" => "multipart/form-data, boundary=" + BOUNDARY + " "} def prepare_query (params) fp = [] params.each {|k,v| if v.respond_to?(:read) fp.push(FileParam.new(k, v.path, v.read)) else fp.push(Param.new(k,v)) end } query = fp.collect {|p| "--" + BOUNDARY + "\r\n" + p.to_multipart }.join("") + "--" + BOUNDARY + "--" return query, HEADER end end end Thanks for your help.

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  • Blackberry Code

    - by Haoest
    I have having difficulties protecting my blackberry application persistent data with ControlledAccess object. According to http://www.blackberry.com/developers/docs/4.5.0api/net/rim/device/api/system/PersistentObject.html, I need a PersistentObject, CodeSignKey, and ControlledAccess objects to work. I have everything except one piece: CodeSignKey codeSigningKey = CodeSigningKey.get( "ACME" ); here, I don't know what to replace for "ACME". Is this the PIN code I chose as I filled out the Code Sign Key? Is it my package name, output file name? The Blackberry API documentation doesn't seem to say anything about this particularly important parameter. Help please, thanks.

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  • Looking for a C# code parser

    - by Blindy
    I'm looking for a set of classes (preferably in the .net framework) that will parse C# code and return a list of functions with parameters, classes with their methods, properties etc. Ideally it would provide all that's needed to build my own intellisense. I have a feeling something like this should be in the .net framework, given all the reflection stuff they offer, but if not then an open source alternative is good enough. What I'm trying to build is basically something like Snippet Compiler, but with a twist. I'm trying to figure out how to get the code dom first. I tried googling for this but I'm not sure what the correct term for this is so I came up empty.

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  • Controlling CodeModel's code output formatting: putting lines between namespace declarations

    - by devoured elysium
    I'm making some experiments with Visual Studio's CodeModel. I tried creating a file with two namespaces in there through VS's Code Model: CodeModel codeModel = projItem.ContainingProject.CodeModel; codeModel.AddNamespace("Namespaces.FirstNamespace", "namespacestest.cs"); codeModel.AddNamespace("Namespaces.SecondNamespace", "namespacestest.cs"); the output of such code is: //file namespacestest.cs namespace Namespaces.FirstNamespace { } namespace Namespaces.SecondNamespace { } Which is almost what I'm looking for. The only catch here is that I'd like to control the spacing: having at least one line between the first and the second namespace. Does by chance anyone know of a way of achieving this? This is what I want: //file namespacestest.cs namespace Namespaces.FirstNamespace { } namespace Namespaces.SecondNamespace { } Thanks

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  • migrating C++ code from structures to classes

    - by eSKay
    I am migrating some C++ code from structures to classes. I was using structures mainly for bit-field optimizations which I do not need any more (I am more worried about speed than saving space now). What are the general guidelines for doing this migration? I am still in the planning stage as this is a very big move affecting a major part of the code. I want to plan everything first before doing it. What are all the essential things I should keep in mind?

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  • C++ refactor common code with one different statement

    - by user231536
    I have two methods f(vector<int>& x, ....) and g(DBConn& x, ....) where the (....) parameters are all identical. The code inside the two methods are completely identical except for one statement where we do different actions based on the type of x: in f(): we do x.push_back(i) in g(): we do x.DeleteRow(i) What is the simplest way to extract the common code into one method and yet have the two different statements? I am thinking of having a templated functor that overloads operator () (int a) but that seems overkill.

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  • Code Golf: Duplicate Character Removal in String

    - by Alex
    The challenge: The shortest code, by character count, that detects and removes duplicate characters in a String. Removal includes ALL instances of the duplicated character (so if you find 3 n's, all three have to go), and original character order needs to be preserved. Example Input 1: nbHHkRvrXbvkn Example Output 1: RrX Example Input 2: nbHHkRbvnrXbvkn Example Output 2: RrX (the second example removes letters that occur three times; some solutions have failed to account for this) (This is based on my other question where I needed the fastest way to do this in C#, but I think it makes good Code Golf across languages.)

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  • Using Gridview in aspx.vb (code-behind)

    - by Tauron Xavenberg
    I need to create a gridview based on 2 different datasources: main and sub-cathegory. And I need to list them like below: Productinfo sub-product 1 sub-product 2 Productinfo sub-product 1 sub-product 2 sub-product 3 sub-product 4 Etc... the thing is that both the "productinfo" and the "sub-product" are dynamic as the number of both can vary, so I would have to create a gridview within a gridview, plus the necessary filters too. For this reason I thought it was best to do it all in code-behind, but I can't understand how to use the gridview-class in codebehind and bind it so that it actually shows something in the main aspx page. Basically what I'm asking for is a simple example of how, when you have nothing but <asp:GridView/> in the aspx -page, can you add components to it and show it, from code-behind (vb)? Thanks.

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  • Help me understand the code snippet in c#

    - by Benny
    I am reading this blog: Pipes and filters pattern I am confused by this code snippet: public class Pipeline<T> { private readonly List<IOperation<T>> operations = new List<IOperation<T>>(); public Pipeline<T> Register(IOperation<T> operation) { operations.Add(operation); return this; } public void Execute() { IEnumerable<T> current = new List<T>(); foreach (IOperation<T> operation in operations) { current = operation.Execute(current); } IEnumerator<T> enumerator = current.GetEnumerator(); while (enumerator.MoveNext()); } } what is the purpose of this statement: while (enumerator.MoveNext());? seems this code is a noop.

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  • Add code to html pages automatically

    - by piede
    I need to add some code to the of several html contained in a folder on my desktop. How can i do that? I am using a prototyping tool (Axure) on Mac and I want to add some html meta tags to the generated pages. These pages can be overwritten every time I generate the prototype. What I need is a sort of script that I can launch after re-generating the prototype, to reinsert the code. There is something for windows but it doesn't work on Mac: http://joshuamorse.com/2009/01/14/axure-protonotes-an-alternative-to-protoshare/ thanks

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  • L'essor du Cloud freiné par l'organisation des entreprises et non par la défiance envers la technologie selon IDC et VMWare

    L'adoption du Cloud serait freinée par l'organisation des entreprises Et non par la défiance vis-à-vis de la technologie selon IDC et VMWare Ce seraient les mentalités au sein des départements informatiques et non le manque de confiance dans la technologie qui freineraient l'adoption du Cloud Computing public, selon le livre blanc publié par IDC et sponsorisé par VMware. L'étude IDC "Accélérer la réussite du cloud hybride et ajuster les mentalités" prévoit que les deux prochaines années marqueront un tournant dans l'adoption du Cloud Computing en Europe. Une entreprise sur trois voit aujourd'hui cette technologie comme une composante essentielle de sa stratégie informati...

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  • A Simple Approach For Presenting With Code Samples

    - by Jesse Taber
    Originally posted on: http://geekswithblogs.net/GruffCode/archive/2013/07/31/a-simple-approach-for-presenting-with-code-samples.aspxI’ve been getting ready for a presentation and have been struggling a bit with the best way to show and execute code samples. I don’t present often (hardly ever), but when I do I like the presentation to have a lot of succinct and executable code snippets to help illustrate the points that I’m making. Depending on what the presentation is about, I might just want to build an entire sample application that I would run during the presentation. In other cases, however, building a full-blown application might not really be the best way to present the code. The presentation I’m working on now is for an open source utility library for dealing with dates and times. I could have probably cooked up a sample app for accepting date and time input and then contrived ways in which it could put the library through its paces, but I had trouble coming up with one app that would illustrate all of the various features of the library that I wanted to highlight. I finally decided that what I really needed was an approach that met the following criteria: Simple: I didn’t want the user interface or overall architecture of a sample application to serve as a distraction from the demonstration of the syntax of the library that the presentation is about. I want to be able to present small bits of code that are focused on accomplishing a single task. Several of these examples will look similar, and that’s OK. I want each sample to “stand on its own” and not rely much on external classes or methods (other than the library that is being presented, of course). “Debuggable” (not really a word, I know): I want to be able to easily run the sample with the debugger attached in Visual Studio should I want to step through any bits of code and show what certain values might be at run time. As far as I know this rules out something like LinqPad, though using LinqPad to present code samples like this is actually a very interesting idea that I might explore another time. Flexible and Selectable: I’m going to have lots of code samples to show, and I want to be able to just package them all up into a single project or module and have an easy way to just run the sample that I want on-demand. Since I’m presenting on a .NET framework library, one of the simplest ways in which I could execute some code samples would be to just create a Console application and use Console.WriteLine to output the pertinent info at run time. This gives me a “no frills” harness from which to run my code samples, and I just hit ‘F5’ to run it with the debugger. This satisfies numbers 1 and 2 from my list of criteria above, but item 3 is a little harder. By default, just running a console application is going to execute the ‘main’ method, and then terminate the program after all code is executed. If I want to have several different code samples and run them one at a time, it would be cumbersome to keep swapping the code I want in and out of the ‘main’ method of the console application. What I really want is an easy way to keep the console app running throughout the whole presentation and just have it run the samples I want when I want. I could setup a simple Windows Forms or WPF desktop application with buttons for the different samples, but then I’m getting away from my first criteria of keeping things as simple as possible. Infinite Loops To The Rescue I found a way to have a simple console application satisfy all three of my requirements above, and it involves using an infinite loop and some Console.ReadLine calls that will give the user an opportunity to break out and exit the program. (All programs that need to run until they are closed explicitly (or crash!) likely use similar constructs behind the scenes. Create a new Windows Forms project, look in the ‘Program.cs’ that gets generated, and then check out the docs for the Application.Run method that it calls.). Here’s how the main method might look: 1: static void Main(string[] args) 2: { 3: do 4: { 5: Console.Write("Enter command or 'exit' to quit: > "); 6: var command = Console.ReadLine(); 7: if ((command ?? string.Empty).Equals("exit", StringComparison.OrdinalIgnoreCase)) 8: { 9: Console.WriteLine("Quitting."); 10: break; 11: } 12: 13: } while (true); 14: } The idea here is the app prompts me for the command I want to run, or I can type in ‘exit’ to break out of the loop and let the application close. The only trick now is to create a set of commands that map to each of the code samples that I’m going to want to run. Each sample is already encapsulated in a single public method in a separate class, so I could just write a big switch statement or create a hashtable/dictionary that maps command text to an Action that will invoke the proper method, but why re-invent the wheel? CLAP For Your Own Presentation I’ve blogged about the CLAP library before, and it turns out that it’s a great fit for satisfying criteria #3 from my list above. CLAP lets you decorate methods in a class with an attribute and then easily invoke those methods from within a console application. CLAP was designed to take the arguments passed into the console app from the command line and parse them to determine which method to run and what arguments to pass to that method, but there’s no reason you can’t re-purpose it to accept command input from within the infinite loop defined above and invoke the corresponding method. Here’s how you might define a couple of different methods to contain two different code samples that you want to run during your presentation: 1: public static class CodeSamples 2: { 3: [Verb(Aliases="one")] 4: public static void SampleOne() 5: { 6: Console.WriteLine("This is sample 1"); 7: } 8:   9: [Verb(Aliases="two")] 10: public static void SampleTwo() 11: { 12: Console.WriteLine("This is sample 2"); 13: } 14: } A couple of things to note about the sample above: I’m using static methods. You don’t actually need to use static methods with CLAP, but the syntax ends up being a bit simpler and static methods happen to lend themselves well to the “one self-contained method per code sample” approach that I want to use. The methods are decorated with a ‘Verb’ attribute. This tells CLAP that they are eligible targets for commands. The “Aliases” argument lets me give them short and easy-to-remember aliases that can be used to invoke them. By default, CLAP just uses the full method name as the command name, but with aliases you can simply the usage a bit. I’m not using any parameters. CLAP’s main feature is its ability to parse out arguments from a command line invocation of a console application and automatically pass them in as parameters to the target methods. My code samples don’t need parameters ,and honestly having them would complicate giving the presentation, so this is a good thing. You could use this same approach to invoke methods with parameters, but you’d have a couple of things to figure out. When you invoke a .NET application from the command line, Windows will parse the arguments and pass them in as a string array (called ‘args’ in the boilerplate console project Program.cs). The parsing that gets done here is smart enough to deal with things like treating strings in double quotes as one argument, and you’d have to re-create that within your infinite loop if you wanted to use parameters. I plan on either submitting a pull request to CLAP to add this capability or maybe just making a small utility class/extension method to do it and posting that here in the future. So I now have a simple class with static methods to contain my code samples, and an infinite loop in my ‘main’ method that can accept text commands. Wiring this all up together is pretty easy: 1: static void Main(string[] args) 2: { 3: do 4: { 5: try 6: { 7: Console.Write("Enter command or 'exit' to quit: > "); 8: var command = Console.ReadLine(); 9: if ((command ?? string.Empty).Equals("exit", StringComparison.OrdinalIgnoreCase)) 10: { 11: Console.WriteLine("Quitting."); 12: break; 13: } 14:   15: Parser.Run<CodeSamples>(new[] { command }); 16: Console.WriteLine("---------------------------------------------------------"); 17: } 18: catch (Exception ex) 19: { 20: Console.Error.WriteLine("Error: " + ex.Message); 21: } 22:   23: } while (true); 24: } Note that I’m now passing the ‘CodeSamples’ class into the CLAP ‘Parser.Run’ as a type argument. This tells CLAP to inspect that class for methods that might be able to handle the commands passed in. I’m also throwing in a little “----“ style line separator and some basic error handling (because I happen to know that some of the samples are going to throw exceptions for demonstration purposes) and I’m good to go. Now during my presentation I can just have the console application running the whole time with the debugger attached and just type in the alias of the code sample method that I want to run when I want to run it.

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  • .NET Code Evolution

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

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