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  • Easy remote communication without WCF

    - by Ralf Westphal
    If you´ve read my previous posts about why I deem WCF more of a problem than a solution and how I think we should switch to asynchronous only communication in distributed application, you might be wondering, how this could be done in an easy way. Since a truely simple example to get started with WCF still is drawing quite some traffic to this blog, let me pick up on that and show you, how to accomplish the same but much easier with an async communication API. For simplicities sake let me put all...(read more)

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  • DNN World 2011

    - by bdukes
    We’re on the plane flying back to St. Louis from DNN World 2011 .  I gave a presentation titled DNN 6 UI/UX Patterns , discussing the form patterns introduced in the administrative modules in DNN 6 (the new look and feel that you immediately noticed after logging into your new DNN 6 site).  Many folks asked about seeing the examples that I presented, and they are available as a repository on github, at https://github.com/bdukes/DNN-World-Demos .  This includes a series of small, one...(read more)

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  • Justification for learning/implementing newer Microsoft technologies

    - by Darren
    I work at a large healthcare organization as a mid-level software developer. I have over 10 years experience in the IT industry using Microsoft technologies (ASP.NET & SQL Server). When I go to conferences, code camps, .net user group meetings, I hear of all kinds of new tools and technologies: MVC, LINQ, Entity Framework, WCF Web Services, etc. I guess you could say I'm in my comfort zone using the same old stuff from asp.net 2.0. I use typed datasets for my data access layer. I use web forms and feature rich server controls with master pages. I know how to use plain old SQL and create queries in my typed datasets to get at data my applications need. Throughout my career, I'm always sensitive to not become obsolete with my skill set. What I currently use works fine and my development time is fast. But I'm concerned that if I were to be laid off, I would be asked in interviews how many MVC apps I've written. Or how I am with LINQ or WCF web services. I know that it doesn't matter how many conferences, books, or videos I watch on some new technology...I have to implement/use it or it simply won't sink in. Also, managers who interview don't care how much someone reads up on something, only real use and experience with a technology. I have a new project to write. I've gone to my manager and have asked for additional time for the project for learning/implementing technology I may not be familiar with. Our organization encourages its employees to "learn and grow" and to continue are education. But I always get resistance when I ask for more time to ramp up on something new to implement. My manager is asking for concrete business reasons for implementing these new technologies. I don't have business reasons. My reasons are because I don't want to become obsolete. I could say it would make the project more maintainable in the future by other developers since at some point people could stop using these older technologies, but that' about all I can think of. Does Linq/Entity Framework/MCV apps perform better? So much so that the customers (users in departments I'm creating this app for) need? I doubt it. I'm interested in you guy's thoughts on this. Do many of you have similar plights with trying to use newer upcoming technologies? I doubt I'm on the bleeding edge of technology, either. Are there "business reasons" that you would bring to light for using these technologies? Thanks in advance! Sorry for the long wall of text.

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  • Code and Slides: Getting Started Building Windows 8 HTML/JavaScript Metro Apps

    - by dwahlin
    This presentation is from a talk I gave at the spring 2012 DevConnections conference. It covers some of the key topics you need to know to get started building Windows 8 HTML/JavaScript Metro apps including navigation options, UI surfaces that can be used, controls, data binding and templates, and animations. View more of my presentations here. Sample code shown in the presentation can be found here. A large number of samples are available in the Windows 8 SDK which can be found here.

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  • Thoughts on iPhone, Flash, IE

    - by guybarrette
    It’s interesting to see the debate caused by the iPhone debate over Flash.  In the new version of the iPhone Developer Program License Agreement, Apple bans Flash and Monotouch: 3.3.1 — Applications may only use Documented APIs in the manner prescribed by Apple and must not use or call any private APIs. Applications must be originally written in Objective-C, C, C++, or JavaScript as executed by the iPhone OS WebKit engine, and only code written in C, C++, and Objective-C may compile and directly link against the Documented APIs (e.g., Applications that link to Documented APIs through an intermediary translation or compatibility layer or tool are prohibited). In Adobe’s last SEC filing, they list the iPhone/iPad as a threat to their business. http://www.sec.gov/Archives/edgar/data/796343/000079634310000007/form_10q.htm#riskfactors We offer our desktop application-based products primarily on Windows and Macintosh platforms. We generally offer our server-based products on the Linux platform as well as the Windows and UNIX platforms. To the extent that there is a slowdown of customer purchases of personal computers on either the Windows or Macintosh platform or in general, to the extent that we have difficulty transitioning product or version releases to new Windows and Macintosh operating systems, or to the extent that significant demand arises for our products or competitive products on other platforms before we choose and are able to offer our products on these platforms our business could be harmed. Additionally, to the extent new releases of operating systems or other third-party products, platforms or devices, such as the Apple iPhone or iPad, make it more difficult for our products to perform, and our customers are persuaded to use alternative technologies, our business could be harmed. I had a conversation recently about IE9 and people were asking why is Microsoft spending money and resources to build IE9 now that we have Silverlight.  It makes just no sense to put so much efforts to support HTML 5 in IE because it’s overlapping with Silverlight, no?  Well, what if Chrome became the dominant browser and all of a sudden, Google would remove the object tag?  Would Microsoft be in the same position as Adobe is right now on the iPhone? What do you think? var addthis_pub="guybarrette";

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  • Resolving harmless binding errors in WPF II : 2 approaches for removing data binding errors due to heterogeneous types in a hierarchical view

    - by akjoshi
    This is a continuation post to my previous post Resolving harmless binding errors in WPF in which I talked about various ways of  resolving different binding errors etc. I recently came across another situation in which we get these binding errors and how they can be resolved. Problem: If you have a tree with 2 types of items in it and you use different DataTypes for each of them, then you will get binding errors because of missing Properties in either one of the item. In our case we had binding...(read more)

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  • Using Native Drag and Drop in HTML 5 pages

    - by nikolaosk
    This is going to be the eighth post in a series of posts regarding HTML 5. You can find the other posts here, here , here , here, here , here and here. In this post I will show you how to implement Drag and Drop functionality in an HTML 5 page using JQuery.This is a great functionality and we do not need to resort anymore to plugins like Silverlight and Flash to achieve this great feature. This is also called a native approach on Drag and Drop.I will use some events and I will write code to respond when these events are fired.As I said earlier we need to write Javascript to implement the drag and drop functionality. I will use the very popular JQuery Library. Please download the library (minified version) from http://jquery.com/downloadI will create a simple HTML page.There will be two thumbnails pics on it. There will also be the drag and drop area where the user will drag the thumb pics into it and they will resize to their actual size. The HTML markup for the page follows<!doctype html><html lang="en"><head><title>Liverpool Legends Gallery</title><meta charset="utf-8"><link rel="stylesheet" type="text/css" href="style.css"><script type="text/javascript" charset="utf-8" src="jquery-1.8.1.min.js"></script>  <script language="JavaScript" src="drag.js"></script>   </head><body><header><h1>A page dedicated to Liverpool Legends</h1><h2>Drag and Drop the thumb image in the designated area to see the full image</h2></header><div id="main"><img src="thumbs/steven-gerrard.jpg"  big="large-images/steven-gerrard-large.jpg" alt="John Barnes"><img src="thumbs/robbie-fowler.jpg" big="large-images/robbie-fowler-large.jpg" alt="Ian Rush"><div id="drag"><p>Drop your image here</p> </div></body></html> There is nothing difficult or fancy in the HTML markup above. I have a link to the external JQuery library and another javascript file that I will implement the whole drag and drop functionality.The code for the css file (style.css) follows#main{  float: left;  width: 340px;  margin-right: 30px;}#drag{  float: left;  width: 400px;  height:300px;  background-color: #c0c0c0;}These are simple CSS rules. This post cannot be a tutorial on CSS.For all these posts I assume that you have the basic HTML,CSS,Javascript skills.Now I am going to create a javascript file (drag.js) to implement the drag and drop functionality.I will provide the whole code for the drag.js file and then I will explain what I am doing in each step.$(function() {          var players = $('#main img');          players.attr('draggable', 'true');                    players.bind('dragstart', function(event) {              var data = event.originalEvent.dataTransfer;               var src = $(this).attr("big");              data.setData("Text", src);               return true;          });          var target = $('#drag');          target.bind('drop', function(event) {            var data = event.originalEvent.dataTransfer;            var src = ( data.getData('Text') );                         var img = $("<img></img>").attr("src", src);            $(this).html(img);            if (event.preventDefault) event.preventDefault();            return(false);          });                   target.bind('dragover', function(event) {                if (event.preventDefault) event.preventDefault();            return false;          });           players.bind('dragend', function(event) {             if (event.preventDefault) event.preventDefault();             return false;           });        });   In these lines var players = $('#main img'); players.attr('draggable', 'true');We grab all the images in the #main div and store them in a variable and then make them draggable.Then in following lines I am using the dragstart event.  players.bind('dragstart', function(event) {              var data = event.originalEvent.dataTransfer;               var src = $(this).attr("big");              data.setData("Text", src);               return true;          }); In this event I am associating the custom data attribute value with the item I am dragging.Then I create a variable to get hold of the dropping area var target = $('#drag'); Then in the following lines I implement the drop event and what happens when the user drops the image in the designated area on the page. target.bind('drop', function(event) {            var data = event.originalEvent.dataTransfer;            var src = ( data.getData('Text') );                         var img = $("<img></img>").attr("src", src);            $(this).html(img);            if (event.preventDefault) event.preventDefault();            return(false);          }); The dragend  event is fired when the user has finished the drag operation        players.bind('dragend', function(event) {             if (event.preventDefault) event.preventDefault();             return false;           }); When this method event.preventDefault() is called , the default action of the event will not be triggered.Please have a look a the picture below to see how the page looks before the drag and drop takes place. Then simply I drag and drop a picture in the dropping area.Have a look at the picture below It works!!! Hope it helps!!  

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  • How can I boost my C# learning curve?

    - by MSU
    I have been learning programming, mostly C# and .net stuff. And I have target to become a fulltime .NET developer. But I am feeling that learning Graph is very slow, I have been learning C# programming, doing some coding everyday, but how I can learn very fast and increase my skills rapidly? I know there should be a balance of coding and reading, as without reading I can't code and without coding I can't increase my skills. SO, I am requesting here suggesting from experts on how I bring more pace to my learning curve? I intend to give 4-6 hours daily for this and on weekends 10+ hours.

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  • Welcome 2011

    - by PSteele
    About this time last year, I wrote a blog post about how January of 2010 was almost over and I hadn’t done a single blog post.  Ugh…  History repeats itself. 2010 in Review If I look back at 2010, it was a great year in terms of technology and development: Visited Redmond to attend the MVP Summit in February.  Had a great time with the MS product teams and got to connect with some really smart people. Continued my work on Visual Studio Magazine’s “C# Corner” column.  About mid-year, the column changed from an every-other-month print column to an every-other-month print column along with bi-monthly web-only articles.  Needless to say, this kept me even busier and away from my blog. Participated in another GiveCamp!  Thanks to the wonderful leadership of Michael Eaton and all of his minions, GiveCamp 2010 was another great success.  Planning for GiveCamp 2011 will be starting soon… I switched to DVCS full time.  After years of being a loyal SVN user, I got bit by the DVCS bug.  I played around with both Mercurial and Git and finally settled on Mercurial.  It’s seamless integration with Windows Explorer along with it’s wealth of plugins made me fall in love.  I can’t imagine going back and using a centralized version control system. Continued to work with the awesome group of talent at SRT Solutions.  Very proud that SRT won it’s third consecutive FastTrack award! Jumped off the BlackBerry train and enjoying the smooth ride of Android.  It was time to replace the old BlackBerry Storm so I did some research and settled on the Motorola DroidX.  I couldn’t be happier.  Android is a slick OS and the DroidX is a sweet piece of hardware.  Been dabbling in some Android development with both Eclipse and IntelliJ IDEA (I like IntelliJ IDEA a lot better!).   2011 Plans On January 1st I was pleasantly surprised to get an email from the Microsoft MVP program letting me know that I had received the MVP award again for my community work in 2010.  I’m honored and humbled to be recognized by Microsoft as well as my peers! I’ll continue to do some Android development.  I’m currently working on a simple app to get me feet wet.  It may even makes it’s way into the Android Market. I’ve got a project that could really benefit from WPF so I’ll be diving into WPF this year.  I’ve played around with WPF a bit in the past – simple demos and learning exercises – but this will give me a chance to build an entire application in WPF.  I’m looking forward to the increased freedom that a WPF UI should give me. I plan on blogging a lot more in 2011! Technorati Tags: Android,MVP,Mercurial,WPF,SRT,GiveCamp

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  • A WPF Image/Text Button

    - by psheriff
    Some of our customers are asking us to give them a Windows 8 look and feel for their applications. This includes things like buttons, tiles, application bars, and other features. In this blog post I will describe how to create a button that looks similar to those you will find in a Windows 8 application bar. In Figure 1 you can see two different kinds of buttons. In the top row is a WPF button where the content of the button includes a Border, an Image and a TextBlock. In the bottom row are four...(read more)

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  • Using IComparable<T> Interface

    - by Pawan_Mishra
    Level : Beginner to Intermediate C# language has constantly evolved over a constant period of time.Each new version introduced new features which changed the way we programmed and solved the problems. Whether it was introduction of generics in C# 2.0 , LINQ in C# 3.0 or concept of dynamic programming in C# 4.0 , each of them had or will have greater impact on our programming style.As a developer we don’t have much option but to evolve and redefine our self in this constantly changing environment...(read more)

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  • Where I can find SQL Generated by Entity framework?

    - by Jalpesh P. Vadgama
    Few days back I was optimizing the performance with Entity framework and Linq queries and I was using LinqPad and looking SQL generated by the Linq or entity framework queries. After some point of time I got the same question in mind that how I can find the SQL Statement generated by Entity framework?. After some struggling I have managed to found the way of finding SQL Statement so I thought it would be a great idea to write a post about  same and share my knowledge about that. So in this post I will explain how to find SQL statements generated Entity framework queries. Read More on dotnetjalps.com

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  • Distinct operator in Linq

    - by Jalpesh P. Vadgama
    Linq operator provides great flexibility and easy way of coding. Let’s again take one more example of distinct operator. As name suggest it will find the distinct elements from IEnumerable. Let’s take an example of array in console application and then we will again print array to see is it working or not. Below is the code for that. In this application I have integer array which contains duplicate elements and then I will apply distinct operator to this and then I will print again result of distinct operators to actually see whether its working or not. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace Experiment { class Program { static void Main(string[] args) { int[] intArray = { 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5 }; var uniqueIntegers = intArray.Distinct(); foreach (var uInteger in uniqueIntegers) { Console.WriteLine(uInteger); } Console.ReadKey(); } } } Below is output as expected.. That’s cool..Stay tuned for more.. Happy programming. Technorati Tags: Linq,Distinct

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  • Microsoft <3 jQuery

    - by Latest Microsoft Blogs
      Today at Mix10 we announced our increased support and involvement in the jQuery Library and how we are working closely with the community and the jQuery Team to accelerate the development of this already powerful front-end library. In recent weeks Read More......(read more)

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  • My Mix10 coup de coeur

    - by guybarrette
    If you ask me what was my Mix10 coup de coeur, I’d have to say Bill Buxton.  I was privileged to spend an hour an a half in a small room with about twelve people and Bill Buxton.  This man has such a incredible background and he is so inspiring.  You could really tell that he is a researcher because as he was talking about something, you could see him thinking about something else and trying at the same time to cross reference that. Here’s a list of videos recorded at Mix.  The first one is the shortest one at 9 minutes. Bytes by MSDN (Interviewed by Tim Huckaby, a legend himself) Mix Day 2 Keynote (Last 1/4) An Hour with Bill Buxton (His Mix session) Bill Buxton & Microsoft Student Insiders at MIX10 Channel 9 Live at MIX10: Bill Buxton & Erik Meijer - Perspectives on Design var addthis_pub="guybarrette";

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  • Dynamic Filtering

    - by Ricardo Peres
    Continuing my previous posts on dynamic LINQ, now it's time for dynamic filtering. For now, I'll focus on string matching. There are three standard operators for string matching, which both NHibernate, Entity Framework and LINQ to SQL recognize: Equals Contains StartsWith EndsWith So, if we want to apply filtering by one of these operators on a string property, we can use this code: public enum MatchType { StartsWith = 0, EndsWith = 1, Contains = 2, Equals = 3 } public static List Filter(IEnumerable enumerable, String propertyName, String filter, MatchType matchType) { return (Filter(enumerable, typeof(T), propertyName, filter, matchType) as List); } public static IList Filter(IEnumerable enumerable, Type elementType, String propertyName, String filter, MatchType matchType) { MethodInfo asQueryableMethod = typeof(Queryable).GetMethods(BindingFlags.Static | BindingFlags.Public).Where(m = (m.Name == "AsQueryable") && (m.ContainsGenericParameters == false)).Single(); IQueryable query = (enumerable is IQueryable) ? (enumerable as IQueryable) : asQueryableMethod.Invoke(null, new Object [] { enumerable }) as IQueryable; MethodInfo whereMethod = typeof(Queryable).GetMethods(BindingFlags.Public | BindingFlags.Static).Where(m = m.Name == "Where").ToArray() [ 0 ].MakeGenericMethod(elementType); MethodInfo matchMethod = typeof(String).GetMethod ( (matchType == MatchType.StartsWith) ? "StartsWith" : (matchType == MatchType.EndsWith) ? "EndsWith" : (matchType == MatchType.Contains) ? "Contains" : "Equals", new Type [] { typeof(String) } ); PropertyInfo displayProperty = elementType.GetProperty(propertyName, BindingFlags.Public | BindingFlags.Instance); MemberExpression member = Expression.MakeMemberAccess(Expression.Parameter(elementType, "n"), displayProperty); MethodCallExpression call = Expression.Call(member, matchMethod, Expression.Constant(filter)); LambdaExpression where = Expression.Lambda(call, member.Expression as ParameterExpression); query = whereMethod.Invoke(null, new Object [] { query, where }) as IQueryable; MethodInfo toListMethod = typeof(Enumerable).GetMethod("ToList", BindingFlags.Static | BindingFlags.Public).MakeGenericMethod(elementType); IList list = toListMethod.Invoke(null, new Object [] { query }) as IList; return (list); } var list = new [] { new { A = "aa" }, new { A = "aabb" }, new { A = "ccaa" }, new { A = "ddaadd" } }; var contains = Filter(list, "A", "aa", MatchType.Contains); var endsWith = Filter(list, "A", "aa", MatchType.EndsWith); var startsWith = Filter(list, "A", "aa", MatchType.StartsWith); var equals = Filter(list, "A", "aa", MatchType.Equals); Perhaps I'll write some more posts on this subject in the near future. SyntaxHighlighter.config.clipboardSwf = 'http://alexgorbatchev.com/pub/sh/2.0.320/scripts/clipboard.swf'; SyntaxHighlighter.brushes.CSharp.aliases = ['c#', 'c-sharp', 'csharp']; SyntaxHighlighter.all();

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  • Action delegate in C#

    - by Jalpesh P. Vadgama
    In last few posts about I have written lots of things about delegates and this post is also part of that series. In this post we are going to learn about Action delegates in C#.  Following is a list of post related to delegates. Delegates in C#. Multicast Delegates in C#. Func Delegates in C#. Action Delegates in c#: As per MSDN action delegates used to pass a method as parameter without explicitly declaring custom delegates. Action Delegates are used to encapsulate method that does not have return value. C# 4.0 Action delegates have following different variants like following. It can take up to 16 parameters. Action – It will be no parameter and does not return any value. Action(T) Action(T1,T2) Action(T1,T2,T3) Action(T1,T2,T3,T4) Action(T1,T2,T3,T4,T5) Action(T1,T2,T3,T4,T5,T6) Action(T1,T2,T3,T4,T5,T6,T7) Action(T1,T2,T3,T4,T5,T6,T7,T8) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14,T15) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14,T15,T16) So for this Action delegate you can have up to 16 parameters for Action.  Sound interesting!!… Enough theory now. It’s time to implement real code. Following is a code for that. using System; using System.Collections.Generic; namespace DelegateExample { class Program { static void Main(string[] args) { Action<String> Print = p => Console.WriteLine(p); Action<String,String> PrintAnother = (p1,p2)=> Console.WriteLine(string.Format("{0} {1}",p1,p2)); Print("Hello"); PrintAnother("Hello","World"); } } } In the above code you can see that I have created two Action delegate Print and PrintAnother. Print have one string parameter and its printing that. While PrintAnother have two string parameter and printing both the strings via Console.Writeline. Now it’s time to run example and following is the output as expected. That’s it. Hope you liked it. Stay tuned for more updates!!

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  • TypeScript first impressions

    - by Bertrand Le Roy
    Anders published a video of his new project today, which aims at creating a superset of JavaScript, that compiles down to regular current JavaScript. Anders is a tremendously clever guy, and it always shows in his work. There is much to like in the enterprise (good code completion, refactoring and adoption of the module pattern instead of namespaces to name three), but a few things made me rise an eyebrow. First, there is no mention of CoffeeScript or Dart, but he does talk briefly about Script# and GWT. This is probably because the target audience seems to be the same as the audience for the latter two, i.e. developers who are more comfortable with statically-typed languages such as C# and Java than dynamic languages such as JavaScript. I don’t think he’s aiming at JavaScript developers. Classes and interfaces, although well executed, are not especially appealing. Second, as any code generation tool (and this is true of CoffeeScript as well), you’d better like the generated code. I didn’t, unfortunately. The code that I saw is not the code I would have written. What’s more, I didn’t always find the TypeScript code especially more expressive than what it gets compiled to. I also have a few questions. Is it possible to duck-type interfaces? For example, if I have an IPoint2D interface with x and y coordinates, can I pass any object that has x and y into a function that expects IPoint2D or do I need to necessarily create a class that implements that interface, and new up an instance that explicitly declares its contract? The appeal of dynamic languages is the ability to make objects as you go. This needs to be kept intact. More technical: why are generated variables and functions prefixed with _ rather than the $ that the EcmaScript spec recommends for machine-generated variables? In conclusion, while this is a good contribution to the set of ideas around JavaScript evolution, I don’t expect a lot of adoption outside of the devoted Microsoft developers, but maybe some influence on the language itself. But I’m often wrong. I would certainly not use it because I disagree with the central motivation for doing this: Anders explicitly says he built this because “writing application-scale JavaScript is hard”. I would restate that “writing application-scale JavaScript is hard for people who are used to statically-typed languages”. The community has built a set of good practices over the last few years that do scale quite well, and many people are successfully developing and maintaining impressive applications directly in JavaScript. You can play with TypeScript here: http://www.typescriptlang.org

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  • Code Contracts: validating arrays and collections

    - by DigiMortal
    Validating collections before using them is very common task when we use built-in generic types for our collections. In this posting I will show you how to validate collections using code contracts. It is cool how much awful looking code you can avoid using code contracts. Failing code Let’s suppose we have method that calculates sum of all invoices in collection. We have class Invoice and one of properties it has is Sum. I don’t introduce here any complex calculations on invoices because we have another problem to solve in this topic. Here is our code. public static decimal CalculateTotal(IList<Invoice> invoices) {     var sum = invoices.Sum(p => p.Sum);     return sum; } This method is very simple but it fails when invoices list contains at least one null. Of course, we can test if invoice is null but having nulls in lists like this is not good idea – it opens green way for different coding bugs in system. Our goal is to react to bugs ASAP at the nearest place they occur. There is one more way how to make our method fail. It happens when invoices is null. I thing it is also one common bugs during development and it even happens in production environments under some conditions that are usually hardly met. Now let’s protect our little calculation method with code contracts. We need two contracts: invoices cannot be null invoices cannot contain any nulls Our first contract is easy but how to write the second one? Solution: Contract.ForAll Preconditions in code are checked using Contract.Ensures method. This method takes boolean value as argument that sais if contract holds or not. There is also method Contract.ForAll that takes collection and predicate that must hold for that collection. Nice thing is ForAll returns boolean. So, we have very simple solution. public static decimal CalculateTotal(IList<Invoice> invoices) {     Contract.Requires(invoices != null);     Contract.Requires(Contract.ForAll<Invoice>(invoices, p => p != null));       var sum = invoices.Sum(p => p.Sum);     return sum; } And here are some lines of code you can use to test the contracts quickly. var invoices = new List<Invoice>(); invoices.Add(new Invoice()); invoices.Add(null); invoices.Add(new Invoice()); //CalculateTotal(null); CalculateTotal(invoices); If your code is covered with unit tests then I suggest you to write tests to check that these contracts hold for every code run. Conclusion Although it seemed at first place that checking all elements in collection may end up with for-loops that does not look so nice we were able to solve our problem nicely. ForAll method of contract class offered us simple mechanism to check collections and it does it smoothly the code-contracts-way. P.S. I suggest you also read devlicio.us blog posting Validating Collections with Code Contracts by Derik Whittaker.

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  • Code from my DevConnections Talks and Workshop

    - by dwahlin
    Thanks to everyone who attended my sessions at DevConnections Las Vegas. I had a great time meeting new people, discussing business problems and solutions and interacting. Here’s the code and slides for the sessions.  For those that came to the full-day Silverlight workshop I’ve included the slides that didn’t get printed plus a ton of code to help you get started with various Silverlight topics.   Get Started Building Silverlight Applications Building Architecturally Sound Silverlight Applications Using WCF RIA Services in Silverlight Applications (will post soon) Silverlight Data Integration Options and Usage Scenarios Silverlight Workshop Code

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  • [Silverlight] How to watermark a WriteableBitmap with a text

    - by Benjamin Roux
    Hello, In my current project, I needed to watermark a WriteableBitmap with a text. As I couldn’t find anything I decided to create a small extension method to do so. public static class WriteableBitmapEx { /// <summary> /// Creates a watermark on the specified image /// </summary> /// <param name="input">The image to create the watermark from</param> /// <param name="watermark">The text to watermark</param> /// <param name="color">The color - default is White</param> /// <param name="fontSize">The font size - default is 50</param> /// <param name="opacity">The opacity - default is 0.25</param> /// <param name="hasDropShadow">Specifies if a drop shadow effect must be added - default is true</param> /// <returns>The watermarked image</returns> public static WriteableBitmap Watermark(this WriteableBitmap input, string watermark, Color color = default(Color), double fontSize = 50, double opacity = 0.25, bool hasDropShadow = true) { var watermarked = GetTextBitmap(watermark, fontSize, color == default(Color) ? Colors.White : color, opacity, hasDropShadow); var width = watermarked.PixelWidth; var height = watermarked.PixelHeight; var result = input.Clone(); var position = new Rect(input.PixelWidth - width - 20 /* right margin */, input.PixelHeight - height, width, height); result.Blit(position, watermarked, new Rect(0, 0, width, height)); return result; } /// <summary> /// Creates a WriteableBitmap from a text /// </summary> /// <param name="text"></param> /// <param name="fontSize"></param> /// <param name="color"></param> /// <param name="opacity"></param> /// <param name="hasDropShadow"></param> /// <returns></returns> private static WriteableBitmap GetTextBitmap(string text, double fontSize, Color color, double opacity, bool hasDropShadow) { TextBlock txt = new TextBlock(); txt.Text = text; txt.FontSize = fontSize; txt.Foreground = new SolidColorBrush(color); txt.Opacity = opacity; if (hasDropShadow) txt.Effect = new DropShadowEffect(); WriteableBitmap bitmap = new WriteableBitmap((int)txt.ActualWidth, (int)txt.ActualHeight); bitmap.Render(txt, null); bitmap.Invalidate(); return bitmap; } } For this code to run, you need the WritableBitmapEx library. As you can see, it’s quite simple. You just need to call the Watermark method and pass it the text you want to add in your image. You can also pass optional parameters like the color, the opacity, the fontsize or if you want a drop shadow effect. I could have specify other parameters like the position or the the font family but you can change the code if you need to. Here’s what it can give Hope this helps.

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