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Persisting model state in ASP.NET MVC using Serialize HTMLHelper

- by shiju

ASP.NET MVC 2 futures assembly provides a HTML helper method Serialize that can be use for persisting your model object. The Serialize helper method will serialize the model object and will persist it in a hidden field in the HTML form. The Serialize helper is very useful when situations like you are making multi-step wizard where a single model class is using for all steps in the wizard. For each step you want to retain the model object's whole state.The below is serializing our model object. The model object should be a Serializable class in order to work with Serialize helper method. <% using (Html.BeginForm("Register","User")) {%><%= Html.Serialize("User",Model) %> This will generate hidden field with name "user" and the value will the serialized format of our model object.In the controller action, you can place the DeserializeAttribute in the action method parameter. [HttpPost] public ActionResult Register([DeserializeAttribute] User user, FormCollection userForm) { TryUpdateModel(user, userForm.ToValueProvider()); //To Do } In the above action method you will get the same model object that you serialized in your view template. We are updating the User model object with the form field values.

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An Introduction to Meteor

- by Stephen.Walther

The goal of this blog post is to give you a brief introduction to Meteor which is a framework for building Single Page Apps. In this blog entry, I provide a walkthrough of building a simple Movie database app. What is special about Meteor? Meteor has two jaw-dropping features: Live HTML – If you make any changes to the HTML, CSS, JavaScript, or data on the server then every client shows the changes automatically without a browser refresh. For example, if you change the background color of a page to yellow then every open browser will show the new yellow background color without a refresh. Or, if you add a new movie to a collection of movies, then every open browser will display the new movie automatically. With Live HTML, users no longer need a refresh button. Changes to an application happen everywhere automatically without any effort. The Meteor framework handles all of the messy details of keeping all of the clients in sync with the server for you. Latency Compensation – When you modify data on the client, these modifications appear as if they happened on the server without any delay. For example, if you create a new movie then the movie appears instantly. However, that is all an illusion. In the background, Meteor updates the database with the new movie. If, for whatever reason, the movie cannot be added to the database then Meteor removes the movie from the client automatically. Latency compensation is extremely important for creating a responsive web application. You want the user to be able to make instant modifications in the browser and the framework to handle the details of updating the database without slowing down the user. Installing Meteor Meteor is licensed under the open-source MIT license and you can start building production apps with the framework right now. Be warned that Meteor is still in the “early preview” stage. It has not reached a 1.0 release. According to the Meteor FAQ, Meteor will reach version 1.0 in “More than a month, less than a year.” Don’t be scared away by that. You should be aware that, unlike most open source projects, Meteor has financial backing. The Meteor project received an $11.2 million round of financing from Andreessen Horowitz. So, it would be a good bet that this project will reach the 1.0 mark. And, if it doesn’t, the framework as it exists right now is still very powerful. Meteor runs on top of Node.js. You write Meteor apps by writing JavaScript which runs both on the client and on the server. You can build Meteor apps on Windows, Mac, or Linux (Although the support for Windows is still officially unofficial). If you want to install Meteor on Windows then download the MSI from the following URL: http://win.meteor.com/ If you want to install Meteor on Mac/Linux then run the following CURL command from your terminal: curl https://install.meteor.com | /bin/sh Meteor will install all of its dependencies automatically including Node.js. However, I recommend that you install Node.js before installing Meteor by installing Node.js from the following address: http://nodejs.org/ If you let Meteor install Node.js then Meteor won’t install NPM which is the standard package manager for Node.js. If you install Node.js and then you install Meteor then you get NPM automatically. Creating a New Meteor App To get a sense of how Meteor works, I am going to walk through the steps required to create a simple Movie database app. Our app will display a list of movies and contain a form for creating a new movie. The first thing that we need to do is create our new Meteor app. Open a command prompt/terminal window and execute the following command: Meteor create MovieApp After you execute this command, you should see something like the following: Follow the instructions: execute cd MovieApp to change to your MovieApp directory, and run the meteor command. Executing the meteor command starts Meteor on port 3000. Open up your favorite web browser and navigate to http://localhost:3000 and you should see the default Meteor Hello World page: Open up your favorite development environment to see what the Meteor app looks like. Open the MovieApp folder which we just created. Here’s what the MovieApp looks like in Visual Studio 2012: Notice that our MovieApp contains three files named MovieApp.css, MovieApp.html, and MovieApp.js. In other words, it contains a Cascading Style Sheet file, an HTML file, and a JavaScript file. Just for fun, let’s see how the Live HTML feature works. Open up multiple browsers and point each browser at http://localhost:3000. Now, open the MovieApp.html page and modify the text “Hello World!” to “Hello Cruel World!” and save the change. The text in all of the browsers should update automatically without a browser refresh. Pretty amazing, right? Controlling Where JavaScript Executes You write a Meteor app using JavaScript. Some of the JavaScript executes on the client (the browser) and some of the JavaScript executes on the server and some of the JavaScript executes in both places. For a super simple app, you can use the Meteor.isServer and Meteor.isClient properties to control where your JavaScript code executes. For example, the following JavaScript contains a section of code which executes on the server and a section of code which executes in the browser: if (Meteor.isClient) { console.log("Hello Browser!"); } if (Meteor.isServer) { console.log("Hello Server!"); } console.log("Hello Browser and Server!"); When you run the app, the message “Hello Browser!” is written to the browser JavaScript console. The message “Hello Server!” is written to the command/terminal window where you ran Meteor. Finally, the message “Hello Browser and Server!” is execute on both the browser and server and the message appears in both places. For simple apps, using Meteor.isClient and Meteor.isServer to control where JavaScript executes is fine. For more complex apps, you should create separate folders for your server and client code. Here are the folders which you can use in a Meteor app: · client – This folder contains any JavaScript which executes only on the client. · server – This folder contains any JavaScript which executes only on the server. · common – This folder contains any JavaScript code which executes on both the client and server. · lib – This folder contains any JavaScript files which you want to execute before any other JavaScript files. · public – This folder contains static application assets such as images. For the Movie App, we need the client, server, and common folders. Delete the existing MovieApp.js, MovieApp.html, and MovieApp.css files. We will create new files in the right locations later in this walkthrough. Combining HTML, CSS, and JavaScript Files Meteor combines all of your JavaScript files, and all of your Cascading Style Sheet files, and all of your HTML files automatically. If you want to create one humongous JavaScript file which contains all of the code for your app then that is your business. However, if you want to build a more maintainable application, then you should break your JavaScript files into many separate JavaScript files and let Meteor combine them for you. Meteor also combines all of your HTML files into a single file. HTML files are allowed to have the following top-level elements: <head> — All <head> files are combined into a single <head> and served with the initial page load. <body> — All <body> files are combined into a single <body> and served with the initial page load. <template> — All <template> files are compiled into JavaScript templates. Because you are creating a single page app, a Meteor app typically will contain a single HTML file for the <head> and <body> content. However, a Meteor app typically will contain several template files. In other words, all of the interesting stuff happens within the <template> files. Displaying a List of Movies Let me start building the Movie App by displaying a list of movies. In order to display a list of movies, we need to create the following four files: · client\movies.html – Contains the HTML for the <head> and <body> of the page for the Movie app. · client\moviesTemplate.html – Contains the HTML template for displaying the list of movies. · client\movies.js – Contains the JavaScript for supplying data to the moviesTemplate. · server\movies.js – Contains the JavaScript for seeding the database with movies. After you create these files, your folder structure should looks like this: Here’s what the client\movies.html file looks like: <head> <title>My Movie App</title> </head> <body> <h1>Movies</h1> {{> moviesTemplate }} </body> Notice that it contains <head> and <body> top-level elements. The <body> element includes the moviesTemplate with the syntax {{> moviesTemplate }}. The moviesTemplate is defined in the client/moviesTemplate.html file: <template name="moviesTemplate"> <ul> {{#each movies}} <li> {{title}} </li> {{/each}} </ul> </template> By default, Meteor uses the Handlebars templating library. In the moviesTemplate above, Handlebars is used to loop through each of the movies using {{#each}}…{{/each}} and display the title for each movie using {{title}}. The client\movies.js JavaScript file is used to bind the moviesTemplate to the Movies collection on the client. Here’s what this JavaScript file looks like: // Declare client Movies collection Movies = new Meteor.Collection("movies"); // Bind moviesTemplate to Movies collection Template.moviesTemplate.movies = function () { return Movies.find(); }; The Movies collection is a client-side proxy for the server-side Movies database collection. Whenever you want to interact with the collection of Movies stored in the database, you use the Movies collection instead of communicating back to the server. The moviesTemplate is bound to the Movies collection by assigning a function to the Template.moviesTemplate.movies property. The function simply returns all of the movies from the Movies collection. The final file which we need is the server-side server\movies.js file: // Declare server Movies collection Movies = new Meteor.Collection("movies"); // Seed the movie database with a few movies Meteor.startup(function () { if (Movies.find().count() == 0) { Movies.insert({ title: "Star Wars", director: "Lucas" }); Movies.insert({ title: "Memento", director: "Nolan" }); Movies.insert({ title: "King Kong", director: "Jackson" }); } }); The server\movies.js file does two things. First, it declares the server-side Meteor Movies collection. When you declare a server-side Meteor collection, a collection is created in the MongoDB database associated with your Meteor app automatically (Meteor uses MongoDB as its database automatically). Second, the server\movies.js file seeds the Movies collection (MongoDB collection) with three movies. Seeding the database gives us some movies to look at when we open the Movies app in a browser. Creating New Movies Let me modify the Movies Database App so that we can add new movies to the database of movies. First, I need to create a new template file – named client\movieForm.html – which contains an HTML form for creating a new movie: <template name="movieForm"> <fieldset> <legend>Add New Movie</legend> <form> <div> <label> Title: <input id="title" /> </label> </div> <div> <label> Director: <input id="director" /> </label> </div> <div> <input type="submit" value="Add Movie" /> </div> </form> </fieldset> </template> In order for the new form to show up, I need to modify the client\movies.html file to include the movieForm.html template. Notice that I added {{> movieForm }} to the client\movies.html file: <head> <title>My Movie App</title> </head> <body> <h1>Movies</h1> {{> moviesTemplate }} {{> movieForm }} </body> After I make these modifications, our Movie app will display the form: The next step is to handle the submit event for the movie form. Below, I’ve modified the client\movies.js file so that it contains a handler for the submit event raised when you submit the form contained in the movieForm.html template: // Declare client Movies collection Movies = new Meteor.Collection("movies"); // Bind moviesTemplate to Movies collection Template.moviesTemplate.movies = function () { return Movies.find(); }; // Handle movieForm events Template.movieForm.events = { 'submit': function (e, tmpl) { // Don't postback e.preventDefault(); // create the new movie var newMovie = { title: tmpl.find("#title").value, director: tmpl.find("#director").value }; // add the movie to the db Movies.insert(newMovie); } }; The Template.movieForm.events property contains an event map which maps event names to handlers. In this case, I am mapping the form submit event to an anonymous function which handles the event. In the event handler, I am first preventing a postback by calling e.preventDefault(). This is a single page app, no postbacks are allowed! Next, I am grabbing the new movie from the HTML form. I’m taking advantage of the template find() method to retrieve the form field values. Finally, I am calling Movies.insert() to insert the new movie into the Movies collection. Here, I am explicitly inserting the new movie into the client-side Movies collection. Meteor inserts the new movie into the server-side Movies collection behind the scenes. When Meteor inserts the movie into the server-side collection, the new movie is added to the MongoDB database associated with the Movies app automatically. If server-side insertion fails for whatever reasons – for example, your internet connection is lost – then Meteor will remove the movie from the client-side Movies collection automatically. In other words, Meteor takes care of keeping the client Movies collection and the server Movies collection in sync. If you open multiple browsers, and add movies, then you should notice that all of the movies appear on all of the open browser automatically. You don’t need to refresh individual browsers to update the client-side Movies collection. Meteor keeps everything synchronized between the browsers and server for you. Removing the Insecure Module To make it easier to develop and debug a new Meteor app, by default, you can modify the database directly from the client. For example, you can delete all of the data in the database by opening up your browser console window and executing multiple Movies.remove() commands. Obviously, enabling anyone to modify your database from the browser is not a good idea in a production application. Before you make a Meteor app public, you should first run the meteor remove insecure command from a command/terminal window: Running meteor remove insecure removes the insecure package from the Movie app. Unfortunately, it also breaks our Movie app. We’ll get an “Access denied” error in our browser console whenever we try to insert a new movie. No worries. I’ll fix this issue in the next section. Creating Meteor Methods By taking advantage of Meteor Methods, you can create methods which can be invoked on both the client and the server. By taking advantage of Meteor Methods you can: 1. Perform form validation on both the client and the server. For example, even if an evil hacker bypasses your client code, you can still prevent the hacker from submitting an invalid value for a form field by enforcing validation on the server. 2. Simulate database operations on the client but actually perform the operations on the server. Let me show you how we can modify our Movie app so it uses Meteor Methods to insert a new movie. First, we need to create a new file named common\methods.js which contains the definition of our Meteor Methods: Meteor.methods({ addMovie: function (newMovie) { // Perform form validation if (newMovie.title == "") { throw new Meteor.Error(413, "Missing title!"); } if (newMovie.director == "") { throw new Meteor.Error(413, "Missing director!"); } // Insert movie (simulate on client, do it on server) return Movies.insert(newMovie); } }); The addMovie() method is called from both the client and the server. This method does two things. First, it performs some basic validation. If you don’t enter a title or you don’t enter a director then an error is thrown. Second, the addMovie() method inserts the new movie into the Movies collection. When called on the client, inserting the new movie into the Movies collection just updates the collection. When called on the server, inserting the new movie into the Movies collection causes the database (MongoDB) to be updated with the new movie. You must add the common\methods.js file to the common folder so it will get executed on both the client and the server. Our folder structure now looks like this: We actually call the addMovie() method within our client code in the client\movies.js file. Here’s what the updated file looks like: // Declare client Movies collection Movies = new Meteor.Collection("movies"); // Bind moviesTemplate to Movies collection Template.moviesTemplate.movies = function () { return Movies.find(); }; // Handle movieForm events Template.movieForm.events = { 'submit': function (e, tmpl) { // Don't postback e.preventDefault(); // create the new movie var newMovie = { title: tmpl.find("#title").value, director: tmpl.find("#director").value }; // add the movie to the db Meteor.call( "addMovie", newMovie, function (err, result) { if (err) { alert("Could not add movie " + err.reason); } } ); } }; The addMovie() method is called – on both the client and the server – by calling the Meteor.call() method. This method accepts the following parameters: · The string name of the method to call. · The data to pass to the method (You can actually pass multiple params for the data if you like). · A callback function to invoke after the method completes. In the JavaScript code above, the addMovie() method is called with the new movie retrieved from the HTML form. The callback checks for an error. If there is an error then the error reason is displayed in an alert (please don’t use alerts for validation errors in a production app because they are ugly!). Summary The goal of this blog post was to provide you with a brief walk through of a simple Meteor app. I showed you how you can create a simple Movie Database app which enables you to display a list of movies and create new movies. I also explained why it is important to remove the Meteor insecure package from a production app. I showed you how to use Meteor Methods to insert data into the database instead of doing it directly from the client. I’m very impressed with the Meteor framework. The support for Live HTML and Latency Compensation are required features for many real world Single Page Apps but implementing these features by hand is not easy. Meteor makes it easy.

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Using Oracle Data in the Business Rules Engine

- by Christopher House

Yesterday I started working on some new functionality that I had planned to implement using the Business Rules Engine. As I got further into it, I realized that some of my rules were going to need to reference some data that resides in an Oracle database. I knew the Business Rules Composer supports using DataConnections and TypedDataTables, but I’d never used this functionality myself, so I wasn’t so sure how it would work with Oracle. As it turns out, it’s very do-able, there’s just little hoop you need to jump through. I fired up BRC and my suspicions were quickly confirmed. BRC only recognizes SQL Server databases when it comes to editing rules. Not letting that deter me, I decided to see if I could “trick” BRE into using Oracle data. On my local SQL server, I created a new database and in that database, created a table that matched the schema of the table I wanted to use in the Oracle database. I then set about creating my rules, referencing the new SQL Server database everywhere I wanted to use Oracle data. Finally, I created a new class library and added a class that implements Microsoft.RuleEngine.IFactRetriever. In that class, I added the necessary code to get a DataSet from the Oracle server, wrap it in a TypedDataTable and assert it into the rule engine. It’s worth pointing out that in my IFactRetriever class, I made sure to set my DataSet name to the name of the database I’d referenced in the BRC and the DataTable’s name to the name of the table that I’d referenced in the BRC. After gac’ing the new class library and deploying my policy, I tested and everything worked as expected.

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SQL SERVER – Attach mdf file without ldf file in Database

- by pinaldave

Background Story: One of my friends recently called up and asked me if I had spare time to look at his database and give him a performance tuning advice. Because I had some free time to help him out, I said yes. I asked him to send me the details of his database structure and sample data. He said that since his database is in a very early stage and is small as of the moment, so he told me that he would like me to have a complete database. My response to him was “Sure! In that case, take a backup of the database and send it to me. I will restore it into my computer and play with it.” He did send me his database; however, his method made me write this quick note here. Instead of taking a full backup of the database and sending it to me, he sent me only the .mdf (primary database file). In fact, I asked for a complete backup (I wanted to review file groups, files, as well as few other details). Upon calling my friend, I found that he was not available. Now, he left me with only a .mdf file. As I had some extra time, I decided to checkout his database structure and get back to him regarding the full backup, whenever I can get in touch with him again. Technical Talk: If the database is shutdown gracefully and there was no abrupt shutdown (power outrages, pulling plugs to machines, machine crashes or any other reasons), it is possible (there’s no guarantee) to attach .mdf file only to the server. Please note that there can be many more reasons for a database that is not getting attached or restored. In my case, the database had a clean shutdown and there were no complex issues. I was able to recreate a transaction log file and attached the received .mdf file. There are multiple ways of doing this. I am listing all of them here. Before using any of them, please consult the Domain Expert in your company or industry. Also, never attempt this on live/production server without the presence of a Disaster Recovery expert. USE [master] GO -- Method 1: I use this method EXEC sp_attach_single_file_db @dbname='TestDb', @physname=N'C:\Program Files\Microsoft SQL Server\MSSQL10.MSSQLSERVER\MSSQL\DATA\TestDb.mdf' GO -- Method 2: CREATE DATABASE TestDb ON (FILENAME = N'C:\Program Files\Microsoft SQL Server\MSSQL10.MSSQLSERVER\MSSQL\DATA\TestDb.mdf') FOR ATTACH_REBUILD_LOG GO Method 2: If one or more log files are missing, they are recreated again. There is one more method which I am demonstrating here but I have not used myself before. According to Book Online, it will work only if there is one log file that is missing. If there are more than one log files involved, all of them are required to undergo the same procedure. -- Method 3: CREATE DATABASE TestDb ON ( FILENAME = N'C:\Program Files\Microsoft SQL Server\MSSQL10.MSSQLSERVER\MSSQL\DATA\TestDb.mdf') FOR ATTACH GO Please read the Book Online in depth and consult DR experts before working on the production server. In my case, the above syntax just worked fine as the database was clean when it was detached. Feel free to write your opinions and experiences for it will help the IT community to learn more from your suggestions and skills. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, Readers Question, SQL, SQL Authority, SQL Backup and Restore, SQL Data Storage, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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Maintaining shared service in ASP.NET MVC Application

- by kazimanzurrashid

Depending on the application sometimes we have to maintain some shared service throughout our application. Let’s say you are developing a multi-blog supported blog engine where both the controller and view must know the currently visiting blog, it’s setting , user information and url generation service. In this post, I will show you how you can handle this kind of case in most convenient way. First, let see the most basic way, we can create our PostController in the following way: public class PostController : Controller { public PostController(dependencies...) { } public ActionResult Index(string blogName, int? page) { BlogInfo blog = blogSerivce.FindByName(blogName); if (blog == null) { return new NotFoundResult(); } IEnumerable<PostInfo> posts = postService.FindPublished(blog.Id, PagingCalculator.StartIndex(page, blog.PostPerPage), blog.PostPerPage); int count = postService.GetPublishedCount(blog.Id); UserInfo user = null; if (HttpContext.User.Identity.IsAuthenticated) { user = userService.FindByName(HttpContext.User.Identity.Name); } return View(new IndexViewModel(urlResolver, user, blog, posts, count, page)); } public ActionResult Archive(string blogName, int? page, ArchiveDate archiveDate) { BlogInfo blog = blogSerivce.FindByName(blogName); if (blog == null) { return new NotFoundResult(); } IEnumerable<PostInfo> posts = postService.FindArchived(blog.Id, archiveDate, PagingCalculator.StartIndex(page, blog.PostPerPage), blog.PostPerPage); int count = postService.GetArchivedCount(blog.Id, archiveDate); UserInfo user = null; if (HttpContext.User.Identity.IsAuthenticated) { user = userService.FindByName(HttpContext.User.Identity.Name); } return View(new ArchiveViewModel(urlResolver, user, blog, posts, count, page, achiveDate)); } public ActionResult Tag(string blogName, string tagSlug, int? page) { BlogInfo blog = blogSerivce.FindByName(blogName); if (blog == null) { return new NotFoundResult(); } TagInfo tag = tagService.FindBySlug(blog.Id, tagSlug); if (tag == null) { return new NotFoundResult(); } IEnumerable<PostInfo> posts = postService.FindPublishedByTag(blog.Id, tag.Id, PagingCalculator.StartIndex(page, blog.PostPerPage), blog.PostPerPage); int count = postService.GetPublishedCountByTag(tag.Id); UserInfo user = null; if (HttpContext.User.Identity.IsAuthenticated) { user = userService.FindByName(HttpContext.User.Identity.Name); } return View(new TagViewModel(urlResolver, user, blog, posts, count, page, tag)); } } As you can see the above code heavily depends upon the current blog and the blog retrieval code is duplicated in all of the action methods, once the blog is retrieved the same blog is passed in the view model. Other than the blog the view also needs the current user and url resolver to render it properly. One way to remove the duplicate blog retrieval code is to create a custom model binder which converts the blog from a blog name and use the blog a parameter in the action methods instead of the string blog name, but it only helps the first half in the above scenario, the action methods still have to pass the blog, user and url resolver etc in the view model. Now lets try to improve the the above code, first lets create a new class which would contain the shared services, lets name it as BlogContext: public class BlogContext { public BlogInfo Blog { get; set; } public UserInfo User { get; set; } public IUrlResolver UrlResolver { get; set; } } Next, we will create an interface, IContextAwareService: public interface IContextAwareService { BlogContext Context { get; set; } } The idea is, whoever needs these shared services needs to implement this interface, in our case both the controller and the view model, now we will create an action filter which will be responsible for populating the context: public class PopulateBlogContextAttribute : FilterAttribute, IActionFilter { private static string blogNameRouteParameter = "blogName"; private readonly IBlogService blogService; private readonly IUserService userService; private readonly BlogContext context; public PopulateBlogContextAttribute(IBlogService blogService, IUserService userService, IUrlResolver urlResolver) { Invariant.IsNotNull(blogService, "blogService"); Invariant.IsNotNull(userService, "userService"); Invariant.IsNotNull(urlResolver, "urlResolver"); this.blogService = blogService; this.userService = userService; context = new BlogContext { UrlResolver = urlResolver }; } public static string BlogNameRouteParameter { [DebuggerStepThrough] get { return blogNameRouteParameter; } [DebuggerStepThrough] set { blogNameRouteParameter = value; } } public void OnActionExecuting(ActionExecutingContext filterContext) { string blogName = (string) filterContext.Controller.ValueProvider.GetValue(BlogNameRouteParameter).ConvertTo(typeof(string), Culture.Current); if (!string.IsNullOrWhiteSpace(blogName)) { context.Blog = blogService.FindByName(blogName); } if (context.Blog == null) { filterContext.Result = new NotFoundResult(); return; } if (filterContext.HttpContext.User.Identity.IsAuthenticated) { context.User = userService.FindByName(filterContext.HttpContext.User.Identity.Name); } IContextAwareService controller = filterContext.Controller as IContextAwareService; if (controller != null) { controller.Context = context; } } public void OnActionExecuted(ActionExecutedContext filterContext) { Invariant.IsNotNull(filterContext, "filterContext"); if ((filterContext.Exception == null) || filterContext.ExceptionHandled) { IContextAwareService model = filterContext.Controller.ViewData.Model as IContextAwareService; if (model != null) { model.Context = context; } } } } As you can see we are populating the context in the OnActionExecuting, which executes just before the controllers action methods executes, so by the time our action methods executes the context is already populated, next we are are assigning the same context in the view model in OnActionExecuted method which executes just after we set the model and return the view in our action methods. Now, lets change the view models so that it implements this interface: public class IndexViewModel : IContextAwareService { // More Codes } public class ArchiveViewModel : IContextAwareService { // More Codes } public class TagViewModel : IContextAwareService { // More Codes } and the controller: public class PostController : Controller, IContextAwareService { public PostController(dependencies...) { } public BlogContext Context { get; set; } public ActionResult Index(int? page) { IEnumerable<PostInfo> posts = postService.FindPublished(Context.Blog.Id, PagingCalculator.StartIndex(page, Context.Blog.PostPerPage), Context.Blog.PostPerPage); int count = postService.GetPublishedCount(Context.Blog.Id); return View(new IndexViewModel(posts, count, page)); } public ActionResult Archive(int? page, ArchiveDate archiveDate) { IEnumerable<PostInfo> posts = postService.FindArchived(Context.Blog.Id, archiveDate, PagingCalculator.StartIndex(page, Context.Blog.PostPerPage), Context.Blog.PostPerPage); int count = postService.GetArchivedCount(Context.Blog.Id, archiveDate); return View(new ArchiveViewModel(posts, count, page, achiveDate)); } public ActionResult Tag(string blogName, string tagSlug, int? page) { TagInfo tag = tagService.FindBySlug(Context.Blog.Id, tagSlug); if (tag == null) { return new NotFoundResult(); } IEnumerable<PostInfo> posts = postService.FindPublishedByTag(Context.Blog.Id, tag.Id, PagingCalculator.StartIndex(page, Context.Blog.PostPerPage), Context.Blog.PostPerPage); int count = postService.GetPublishedCountByTag(tag.Id); return View(new TagViewModel(posts, count, page, tag)); } } Now, the last thing where we have to glue everything, I will be using the AspNetMvcExtensibility to register the action filter (as there is no better way to inject the dependencies in action filters). public class RegisterFilters : RegisterFiltersBase { private static readonly Type controllerType = typeof(Controller); private static readonly Type contextAwareType = typeof(IContextAwareService); protected override void Register(IFilterRegistry registry) { TypeCatalog controllers = new TypeCatalogBuilder() .Add(GetType().Assembly) .Include(type => controllerType.IsAssignableFrom(type) && contextAwareType.IsAssignableFrom(type)); registry.Register<PopulateBlogContextAttribute>(controllers); } } Thoughts and Comments?

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Table sorting & pagination with jQuery and Razor in ASP.NET MVC

- by hajan

Introduction jQuery enjoys living inside pages which are built on top of ASP.NET MVC Framework. The ASP.NET MVC is a place where things are organized very well and it is quite hard to make them dirty, especially because the pattern enforces you on purity (you can still make it dirty if you want so ;) ). We all know how easy is to build a HTML table with a header row, footer row and table rows showing some data. With ASP.NET MVC we can do this pretty easy, but, the result will be pure HTML table which only shows data, but does not includes sorting, pagination or some other advanced features that we were used to have in the ASP.NET WebForms GridView. Ok, there is the WebGrid MVC Helper, but what if we want to make something from pure table in our own clean style? In one of my recent projects, I’ve been using the jQuery tablesorter and tablesorter.pager plugins that go along. You don’t need to know jQuery to make this work… You need to know little CSS to create nice design for your table, but of course you can use mine from the demo… So, what you will see in this blog is how to attach this plugin to your pure html table and a div for pagination and make your table with advanced sorting and pagination features. Demo Project Resources The resources I’m using for this demo project are shown in the following solution explorer window print screen: Content/images – folder that contains all the up/down arrow images, pagination buttons etc. You can freely replace them with your own, but keep the names the same if you don’t want to change anything in the CSS we will built later. Content/Site.css – The main css theme, where we will add the theme for our table too Controllers/HomeController.cs – The controller I’m using for this project Models/Person.cs – For this demo, I’m using Person.cs class Scripts – jquery-1.4.4.min.js, jquery.tablesorter.js, jquery.tablesorter.pager.js – required script to make the magic happens Views/Home/Index.cshtml – Index view (razor view engine) the other items are not important for the demo. ASP.NET MVC 1. Model In this demo I use only one Person class which defines Person entity with several properties. You can use your own model, maybe one which will access data from database or any other resource. Person.cs public class Person { public string Name { get; set; } public string Surname { get; set; } public string Email { get; set; } public int? Phone { get; set; } public DateTime? DateAdded { get; set; } public int? Age { get; set; } public Person(string name, string surname, string email, int? phone, DateTime? dateadded, int? age) { Name = name; Surname = surname; Email = email; Phone = phone; DateAdded = dateadded; Age = age; } } 2. View In our example, we have only one Index.chtml page where Razor View engine is used. Razor view engine is my favorite for ASP.NET MVC because it’s very intuitive, fluid and keeps your code clean. 3. Controller Since this is simple example with one page, we use one HomeController.cs where we have two methods, one of ActionResult type (Index) and another GetPeople() used to create and return list of people. HomeController.cs public class HomeController : Controller { // // GET: /Home/ public ActionResult Index() { ViewBag.People = GetPeople(); return View(); } public List<Person> GetPeople() { List<Person> listPeople = new List<Person>(); listPeople.Add(new Person("Hajan", "Selmani", "[email protected]", 070070070,DateTime.Now, 25)); listPeople.Add(new Person("Straight", "Dean", "[email protected]", 123456789, DateTime.Now.AddDays(-5), 35)); listPeople.Add(new Person("Karsen", "Livia", "[email protected]", 46874651, DateTime.Now.AddDays(-2), 31)); listPeople.Add(new Person("Ringer", "Anne", "[email protected]", null, DateTime.Now, null)); listPeople.Add(new Person("O'Leary", "Michael", "[email protected]", 32424344, DateTime.Now, 44)); listPeople.Add(new Person("Gringlesby", "Anne", "[email protected]", null, DateTime.Now.AddDays(-9), 18)); listPeople.Add(new Person("Locksley", "Stearns", "[email protected]", 2135345, DateTime.Now, null)); listPeople.Add(new Person("DeFrance", "Michel", "[email protected]", 235325352, DateTime.Now.AddDays(-18), null)); listPeople.Add(new Person("White", "Johnson", null, null, DateTime.Now.AddDays(-22), 55)); listPeople.Add(new Person("Panteley", "Sylvia", null, 23233223, DateTime.Now.AddDays(-1), 32)); listPeople.Add(new Person("Blotchet-Halls", "Reginald", null, 323243423, DateTime.Now, 26)); listPeople.Add(new Person("Merr", "South", "[email protected]", 3232442, DateTime.Now.AddDays(-5), 85)); listPeople.Add(new Person("MacFeather", "Stearns", "[email protected]", null, DateTime.Now, null)); return listPeople; } } TABLE CSS/HTML DESIGN Now, lets start with the implementation. First of all, lets create the table structure and the main CSS. 1. HTML Structure @{ Layout = null; } <!DOCTYPE html> <html> <head> <title>ASP.NET & jQuery</title>  </head> <body> <div> <table class="tablesorter"> <thead> <tr> <th> value </th> </tr> </thead> <tbody> <tr> <td>value</td> </tr> </tbody> <tfoot> <tr> <th> value </th> </tr> </tfoot> </table> <div id="pager"> </div> </div> </body> </html> So, this is the main structure you need to create for each of your tables where you want to apply the functionality we will create. Of course the scripts are referenced once ;). As you see, our table has class tablesorter and also we have a div with id pager. In the next steps we will use both these to create the needed functionalities. The complete Index.cshtml coded to get the data from controller and display in the page is: <body> <div> <table class="tablesorter"> <thead> <tr> <th>Name</th> <th>Surname</th> <th>Email</th> <th>Phone</th> <th>Date Added</th> </tr> </thead> <tbody> @{ foreach (var p in ViewBag.People) { <tr> <td>@p.Name</td> <td>@p.Surname</td> <td>@p.Email</td> <td>@p.Phone</td> <td>@p.DateAdded</td> </tr> } } </tbody> <tfoot> <tr> <th>Name</th> <th>Surname</th> <th>Email</th> <th>Phone</th> <th>Date Added</th> </tr> </tfoot> </table> <div id="pager" style="position: none;"> <form> <img src="@Url.Content("~/Content/images/first.png")" class="first" /> <img src="@Url.Content("~/Content/images/prev.png")" class="prev" /> <input type="text" class="pagedisplay" /> <img src="@Url.Content("~/Content/images/next.png")" class="next" /> <img src="@Url.Content("~/Content/images/last.png")" class="last" /> <select class="pagesize"> <option selected="selected" value="5">5</option> <option value="10">10</option> <option value="20">20</option> <option value="30">30</option> <option value="40">40</option> </select> </form> </div> </div> </body> So, mainly the structure is the same. I have added @Razor code to create table with data retrieved from the ViewBag.People which has been filled with data in the home controller. 2. CSS Design The CSS code I’ve created is: /* DEMO TABLE */ body { font-size: 75%; font-family: Verdana, Tahoma, Arial, "Helvetica Neue", Helvetica, Sans-Serif; color: #232323; background-color: #fff; } table { border-spacing:0; border:1px solid gray;} table.tablesorter thead tr .header { background-image: url(images/bg.png); background-repeat: no-repeat; background-position: center right; cursor: pointer; } table.tablesorter tbody td { color: #3D3D3D; padding: 4px; background-color: #FFF; vertical-align: top; } table.tablesorter tbody tr.odd td { background-color:#F0F0F6; } table.tablesorter thead tr .headerSortUp { background-image: url(images/asc.png); } table.tablesorter thead tr .headerSortDown { background-image: url(images/desc.png); } table th { width:150px; border:1px outset gray; background-color:#3C78B5; color:White; cursor:pointer; } table thead th:hover { background-color:Yellow; color:Black;} table td { width:150px; border:1px solid gray;} PAGINATION AND SORTING Now, when everything is ready and we have the data, lets make pagination and sorting functionalities 1. jQuery Scripts referencing <link href="@Url.Content("~/Content/Site.css")" rel="stylesheet" type="text/css" /> <script src="@Url.Content("~/Scripts/jquery-1.4.4.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.tablesorter.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.tablesorter.pager.js")" type="text/javascript"></script> 2. jQuery Sorting and Pagination script <script type="text/javascript"> $(function () { $("table.tablesorter").tablesorter({ widthFixed: true, sortList: [[0, 0]] }) .tablesorterPager({ container: $("#pager"), size: $(".pagesize option:selected").val() }); }); </script> So, with only two lines of code, I’m using both tablesorter and tablesorterPager plugins, giving some options to both these. Options added: tablesorter - widthFixed: true – gives fixed width of the columns tablesorter - sortList[[0,0]] – An array of instructions for per-column sorting and direction in the format: [[columnIndex, sortDirection], ... ] where columnIndex is a zero-based index for your columns left-to-right and sortDirection is 0 for Ascending and 1 for Descending. A valid argument that sorts ascending first by column 1 and then column 2 looks like: [[0,0],[1,0]] (source: http://tablesorter.com/docs/) tablesorterPager – container: $(“#pager”) – tells the pager container, the div with id pager in our case. tablesorterPager – size: the default size of each page, where I get the default value selected, so if you put selected to any other of the options in your select list, you will have this number of rows as default per page for the table too. END RESULTS 1. Table once the page is loaded (default results per page is 5 and is automatically sorted by 1st column as sortList is specified) 2. Sorted by Phone Descending 3. Changed pagination to 10 items per page 4. Sorted by Phone and Name (use SHIFT to sort on multiple columns) 5. Sorted by Date Added 6. Page 3, 5 items per page ADDITIONAL ENHANCEMENTS We can do additional enhancements to the table. We can make search for each column. I will cover this in one of my next blogs. Stay tuned. DEMO PROJECT You can download demo project source code from HERE.CONCLUSION Once you finish with the demo, run your page and open the source code. You will be amazed of the purity of your code.Working with pagination in client side can be very useful. One of the benefits is performance, but if you have thousands of rows in your tables, you will get opposite result when talking about performance. Hence, sometimes it is nice idea to make pagination on back-end. So, the compromise between both approaches would be best to combine both of them. I use at most up to 500 rows on client-side and once the user reach the last page, we can trigger ajax postback which can get the next 500 rows using server-side pagination of the same data. I would like to recommend the following blog post http://weblogs.asp.net/gunnarpeipman/archive/2010/09/14/returning-paged-results-from-repositories-using-pagedresult-lt-t-gt.aspx, which will help you understand how to return page results from repository. I hope this was helpful post for you. Wait for my next posts ;). Please do let me know your feedback. Best Regards, Hajan

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Using Unity – Part 2

- by nmarun

In the first part of this series, we created a simple project and learned how to implement IoC pattern using Unity. In this one, I’ll show how you can instantiate other types that implement our IProduct interface. One place where this one would want to use this feature is to create mock types for testing purposes. Alright, let’s dig in. I added another class – Product2.cs to the ProductModel project. 1: public class Product2 : IProduct 2: { 3: public string Name { get; set;} 4: public Category Category { get; set; } 5: public DateTime MfgDate { get;set; } 6: 7: public Product2() 8: { 9: Name = "Canon Digital Rebel XTi"; 10: Category = new Category {Name = "Electronics", SubCategoryName = "Digital Cameras"}; 11: MfgDate = DateTime.Now; 12: } 13: 14: public string WriteProductDetails() 15: { 16: return string.Format("Name: {0}<br/>Category: {1}<br/>Mfg Date: {2}", 17: Name, Category, MfgDate.ToShortDateString()); 18: } 19: } Highlights of this class are that it implements IProduct interface and it has some different properties than the Product class. The Category class looks like below: 1: public class Category 2: { 3: public string Name { get; set; } 4: public string SubCategoryName { get; set; } 5: 6: public override string ToString() 7: { 8: return string.Format("{0} - {1}", Name, SubCategoryName); 9: } 10: } We’ll go to our web.config file to add the configuration information about this new class – Product2 that we created. Let’s first add a typeAlias element. 1: <typeAlias alias="Product2" type="ProductModel.Product2, ProductModel"/> That’s all that is needed for us to get an instance of Product2 in our application. I have a new button added to the .aspx page and the click event of this button is where all the magic happens: 1: private IUnityContainer unityContainer; 2: protected void Page_Load(object sender, EventArgs e) 3: { 4: unityContainer = Application["UnityContainer"] as IUnityContainer; 5: 6: if (unityContainer == null) 7: { 8: productDetailsLabel.Text = "ERROR: Unity Container not populated in Global.asax.<p />"; 9: } 10: else 11: { 12: if (!IsPostBack) 13: { 14: IProduct productInstance = unityContainer.Resolve<IProduct>(); 15: productDetailsLabel.Text = productInstance.WriteProductDetails(); 16: } 17: } 18: } 19: 20: protected void Product2Button_Click(object sender, EventArgs e) 21: { 22: unityContainer.RegisterType<IProduct, Product2>(); 23: IProduct product2Instance = unityContainer.Resolve<IProduct>(); 24: productDetailsLabel.Text = product2Instance.WriteProductDetails(); 25: } The unityContainer instance is set in the Page_Load event. Line 22 in the click event of the Product2Button registers a type mapping in the container. In English, this means that when unityContainer tries to resolve for IProduct, it gets an instance of Product2. Once this code runs, following output is rendered: There’s another way of doing this. You can resolve an instance of the requested type with a name from the container. We’ll have to update the container element of our web.config file to include the following: 1: <container name="unityContainer"> 2: <types> 3: <type type="IProduct" mapTo="Product"/> 4:  5: <type type="IProduct" mapTo="Product" name="LegacyProduct" /> 6:  7: <type type="IProduct" mapTo="Product2" name="NewProduct" /> 8: </types> 9: </container> I’ve added a Dropdownlist and a button to the design page: 1: <asp:DropDownList ID="ModelTypesList" runat="server"> 2: <asp:ListItem Text="Legacy Product" Value="LegacyProduct" /> 3: <asp:ListItem Text="New Product" Value="NewProduct" /> 4: </asp:DropDownList> 5: <br /> 6: <asp:Button ID="SelectedModelButton" Text="Get Selected Instance" runat="server" 7: onclick="SelectedModelButton_Click" /> 1: protected void SelectedModelButton_Click(object sender, EventArgs e) 2: { 3: // get the selected value: LegacyProduct or NewProduct 4: string modelType = ModelTypesList.SelectedValue; 5: // pass the modelType to the Resolve method 6: IProduct customModel = unityContainer.Resolve<IProduct>(modelType); 7: productDetailsLabel.Text = customModel.WriteProductDetails(); 8: } Pretty straight forward right? The only thing to note here is that the values in the dropdownlist item need to match the name attribute of the type. Depending on what you select, you’ll get an instance of either the Product class or the Product2 class and the corresponding WriteProductDetails() method is called. Now you see, how either of these methods can be used to create mock objects your the test project. See the code here. I’ll continue to share more of Unity in the next blog.

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PHP PSR-0 + several namespaces in one file and autoload

- by Nemoden

I've been thinking for a while about defining several namespaces in one php file and so, having several classes inside this file. Suppose, I want to implement something like Doctrine\ORM\Query\Expr: Expr.php Expr |-- Andx.php |-- Base.php |-- Comparison.php |-- Composite.php |-- From.php |-- Func.php |-- GroupBy.php |-- Join.php |-- Literal.php |-- Math.php |-- OrderBy.php |-- Orx.php `-- Select.php It would be nice if I had all of this in one file - Expr.php: namespace Doctrine\ORM\Query; class Expr { // code } namespace Doctrine\ORM\Query\Expr; class Func { // code } // etc... What I'm thinking of is directories naming convention and, unlike PSR-0 having several classes and namespaces in one file. It's best explained by the code: ls Doctrine/orm/query Expr.php that's it - only Expr.php Since Expr.php is somewhat I call a "meta-namespace" for Expr\Func, it make sense to place all the classes inside Expr.php (as shown above). So, the vendor name is still starts with an uppercased letter (Doctrine) and the other parts of namespace start with lowercased letter. We can write an autoload so it would respect this notion: function load_class($class) { if (class_exists($class)) { return true; } $tokenized_path = explode(array("_", "\\"), DIRECTORY_SEPARATOR, $class); // array('Doctrine', 'orm', 'query', 'Expr', 'Func'); // ^^^^ // first, we are looking for first uppercased namespace part // and if it's not last (not the class name), we use it as a filename // and wiping away the rest to compose a path to a file we need to include if (FALSE !== ($meta_class_index = find_meta_class($tokenized_path))) { $new_tokenized_path = array_slice($tokenized_path, 0, $meta_class_index); $path_to_class = implode(DIRECTORY_SEPARATOR, $new_tokenized_path); } else { // no meta class found $path_to_class = implode(DIRECTORY_SEPARATOR, $tokenized_path); } if (file_exists($path_to_class.'.php')) { require_once $path_to_class.'.php'; } return false; } Another reason to do so is to reduce a number of php files scattered among directories. Usually you check file existence before you require a file to fail gracefully: file_exists($path_to_class.'.php'); If you take a look at actual Doctrine\ORM\Query\Expr code, you'll see they use all of the "inner-classes", so you actually do: file_exists("/path/to/Doctrine/ORM/Query/Expr.php"); file_exists("/path/to/Doctrine/ORM/Query/Expr/AndX.php"); file_exists("/path/to/Doctrine/ORM/Query/Expr/Base.php"); file_exists("/path/to/Doctrine/ORM/Query/Expr/Comparison.php"); file_exists("/path/to/Doctrine/ORM/Query/Expr/Composite.php"); file_exists("/path/to/Doctrine/ORM/Query/Expr/From.php"); file_exists("/path/to/Doctrine/ORM/Query/Expr/Func.php"); file_exists("/path/to/Doctrine/ORM/Query/Expr/GroupBy.php"); file_exists("/path/to/Doctrine/ORM/Query/Expr/Join.php"); file_exists("/path/to/Doctrine/ORM/Query/Expr/Literal.php"); file_exists("/path/to/Doctrine/ORM/Query/Expr/Math.php"); file_exists("/path/to/Doctrine/ORM/Query/Expr/OrderBy.php"); file_exists("/path/to/Doctrine/ORM/Query/Expr/Orx.php"); file_exists("/path/to/Doctrine/ORM/Query/Expr/Select.php"); in your autoload which causes quite a few I/O reads. Isn't it too much to check on each user's hit? I'm just putting this on a discussion. I want to hear from another PHP programmers what do they think of it. And, of course, if you have a silver bullet addressing this problems I've designated here, please share. I also have been thinking if my vogue question fits here and according to the FAQ it seems like this question addresses "software architecture" problem slash proposal. I'm sorry if my scribble may seem a bit clunky :) Thanks.

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URL Routing in ASP.NET 4.0

In the .NET Framework 3.5 SP1, Microsoft introduced ASP.NET Routing, which decouples the URL of a resource from the physical file on the web server. With ASP.NET Routing you, the developer, define routing rules map route patterns to a class that generates the content. For example, you might indicate that the URL Categories/CategoryName maps to a class that takes the CategoryName and generates HTML that lists that category's products in a grid. With such a mapping, users could view products for the Beverages category by visiting www.yoursite.com/Categories/Beverages. In .NET 3.5 SP1, ASP.NET Routing was primarily designed for ASP.NET MVC applications, although as discussed in Using ASP.NET Routing Without ASP.NET MVC it is possible to implement ASP.NET Routing in a Web Forms application, as well. However, implementing ASP.NET Routing in a Web Forms application involves a bit of seemingly excessive legwork. In a Web Forms scenario we typically want to map a routing pattern to an actual ASP.NET page. To do so we need to create a route handler class that is invoked when the routing URL is requested and, in a sense, dispatches the request to the appropriate ASP.NET page. For instance, to map a route to a physical file, such as mapping Categories/CategoryName to ShowProductsByCategory.aspx - requires three steps: (1) Define the mapping in Global.asax, which maps a route pattern to a route handler class; (2) Create the route handler class, which is responsible for parsing the URL, storing any route parameters into some location that is accessible to the target page (such as HttpContext.Items), and returning an instance of the target page or HTTP Handler that handles the requested route; and (3) writing code in the target page to grab the route parameters and use them in rendering its content. Given how much effort it took to just read the preceding sentence (let alone write it) you can imagine that implementing ASP.NET Routing in a Web Forms application is not necessarily the most straightforward task. The good news is that ASP.NET 4.0 has greatly simplified ASP.NET Routing for Web Form applications by adding a number of classes and helper methods that can be used to encapsulate the aforementioned complexity. With ASP.NET 4.0 it's easier to define the routing rules and there's no need to create a custom route handling class. This article details these enhancements. Read on to learn more! Read More >

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GuestPost: Unit Testing Entity Framework (v1) Dependent Code using TypeMock Isolator

- by Eric Nelson

Time for another guest post (check out others in the series), this time bringing together the world of mocking with the world of Entity Framework. A big thanks to Moses for agreeing to do this. Unit Testing Entity Framework Dependent Code using TypeMock Isolator by Muhammad Mosa Introduction Unit testing data access code in my opinion is a challenging thing. Let us consider unit tests and integration tests. In integration tests you are allowed to have environmental dependencies such as a physical database connection to insert, update, delete or retrieve your data. However when performing unit tests it is often much more efficient and productive to remove environmental dependencies. Instead you will need to fake these dependencies. Faking a database (also known as mocking) can be relatively straight forward but the version of Entity Framework released with .Net 3.5 SP1 has a number of implementation specifics which actually makes faking the existence of a database quite difficult. Faking Entity Framework As mentioned earlier, to effectively unit test you will need to fake/simulate Entity Framework calls to the database. There are many free open source mocking frameworks that can help you achieve this but it will require additional effort to overcome & workaround a number of limitations in those frameworks. Examples of these limitations include: Not able to fake calls to non virtual methods Not able to fake sealed classes Not able to fake LINQ to Entities queries (replace database calls with in-memory collection calls) There is a mocking framework which is flexible enough to handle limitations such as those above. The commercially available TypeMock Isolator can do the job for you with less code and ultimately more readable unit tests. I’m going to demonstrate tackling one of those limitations using MoQ as my mocking framework. Then I will tackle the same issue using TypeMock Isolator. Mocking Entity Framework with MoQ One basic need when faking Entity Framework is to fake the ObjectContext. This cannot be done by passing any connection string. You have to pass a correct Entity Framework connection string that specifies CSDL, SSDL and MSL locations along with a provider connection string. Assuming we are going to do that, we’ll explore another limitation. The limitation we are going to face now is related to not being able to fake calls to non-virtual/overridable members with MoQ. I have the following repository method that adds an EntityObject (instance of a Blog entity) to Blogs entity set in an ObjectContext. public override void Add(Blog blog) { if(BlogContext.Blogs.Any(b=>b.Name == blog.Name)) { throw new InvalidOperationException("Blog with same name already exists!"); } BlogContext.AddToBlogs(blog); } The method does a very simple check that the name of the new Blog entity instance doesn’t exist. This is done through the simple LINQ query above. If the blog doesn’t already exist it simply adds it to the current context to be saved when SaveChanges of the ObjectContext instance (e.g. BlogContext) is called. However, if a blog with the same name exits, and exception (InvalideOperationException) will be thrown. Let us now create a unit test for the Add method using MoQ. [TestMethod] [ExpectedException(typeof(InvalidOperationException))] public void Add_Should_Throw_InvalidOperationException_When_Blog_With_Same_Name_Already_Exits() { //(1) We shouldn't depend on configuration when doing unit tests! But, //its a workaround to fake the ObjectContext string connectionString = ConfigurationManager .ConnectionStrings["MyBlogConnString"] .ConnectionString; //(2) Arrange: Fake ObjectContext var fakeContext = new Mock<MyBlogContext>(connectionString); //(3) Next Line will pass, as ObjectContext now can be faked with proper connection string var repo = new BlogRepository(fakeContext.Object); //(4) Create fake ObjectQuery<Blog>. Will be used to substitute MyBlogContext.Blogs property var fakeObjectQuery = new Mock<ObjectQuery<Blog>>("[Blogs]", fakeContext.Object); //(5) Arrange: Set Expectations //Next line will throw an exception by MoQ: //System.ArgumentException: Invalid setup on a non-overridable member fakeContext.SetupGet(c=>c.Blogs).Returns(fakeObjectQuery.Object); fakeObjectQuery.Setup(q => q.Any(b => b.Name == "NewBlog")).Returns(true); //Act repo.Add(new Blog { Name = "NewBlog" }); } This test method is checking to see if the correct exception ([ExpectedException(typeof(InvalidOperationException))]) is thrown when a developer attempts to Add a blog with a name that’s already exists. On (1) a connection string is initialized from configuration file. To retrieve the full connection string. On (2) a fake ObjectContext is being created. The ObjectContext here is MyBlogContext and its being created using this var fakeContext = new Mock<MyBlogContext>(connectionString); This way a fake context is being created using MoQ. On (3) a BlogRepository instance is created. BlogRepository has dependency on generate Entity Framework ObjectContext, MyObjectContext. And so the fake context is passed to the constructor. var repo = new BlogRepository(fakeContext.Object); On (4) a fake instance of ObjectQuery<Blog> is being created to use as a substitute to MyObjectContext.Blogs property as we will see in (5). On (5) setup an expectation for calling Blogs property of MyBlogContext and substitute the return result with the fake ObjectQuery<Blog> instance created on (4). When you run this test it will fail with MoQ throwing an exception because of this line: fakeContext.SetupGet(c=>c.Blogs).Returns(fakeObjectQuery.Object); This happens because the generate property MyBlogContext.Blogs is not virtual/overridable. And assuming it is virtual or you managed to make it virtual it will fail at the following line throwing the same exception: fakeObjectQuery.Setup(q => q.Any(b => b.Name == "NewBlog")).Returns(true); This time the test will fail because the Any extension method is not virtual/overridable. You won’t be able to replace ObjectQuery<Blog> with fake in memory collection to test your LINQ to Entities queries. Now lets see how replacing MoQ with TypeMock Isolator can help. Mocking Entity Framework with TypeMock Isolator The following is the same test method we had above for MoQ but this time implemented using TypeMock Isolator: [TestMethod] [ExpectedException(typeof(InvalidOperationException))] public void Add_New_Blog_That_Already_Exists_Should_Throw_InvalidOperationException() { //(1) Create fake in memory collection of blogs var fakeInMemoryBlogs = new List<Blog> {new Blog {Name = "FakeBlog"}}; //(2) create fake context var fakeContext = Isolate.Fake.Instance<MyBlogContext>(); //(3) Setup expected call to MyBlogContext.Blogs property through the fake context Isolate.WhenCalled(() => fakeContext.Blogs) .WillReturnCollectionValuesOf(fakeInMemoryBlogs.AsQueryable()); //(4) Create new blog with a name that already exits in the fake in memory collection in (1) var blog = new Blog {Name = "FakeBlog"}; //(5) Instantiate instance of BlogRepository (Class under test) var repo = new BlogRepository(fakeContext); //(6) Acting by adding the newly created blog () repo.Add(blog); } When running the above test method it will pass as the Add method of BlogRepository is going to throw an InvalidOperationException which is the expected behaviour. Nothing prevents us from faking out the database interaction! Even faking ObjectContext at (2) didn’t require a connection string. On (3) Isolator sets up a faking result for MyBlogContext.Blogs when its being called through the fake instance fakeContext created on (2). The faking result is just an in-memory collection declared an initialized on (1). Finally at (6) action we call the Add method of BlogRepository passing a new Blog instance that has a name that’s already exists in the fake in-memory collection which we set up at (1). As expected the test will pass because it will throw the expected exception defined on top of the test method - InvalidOperationException. TypeMock Isolator succeeded in faking Entity Framework with ease. Conclusion We explored how to write a simple unit test using TypeMock Isolator for code which is using Entity Framework. We also explored a few of the limitations of other mocking frameworks which TypeMock is successfully able to handle. There are workarounds that you can use to overcome limitations when using MoQ or Rhino Mock, however the workarounds will require you to write more code and your tests will likely be more complex. For a comparison between different mocking frameworks take a look at this document produced by TypeMock. You might also want to check out this open source project to compare mocking frameworks. I hope you enjoyed this post Muhammad Mosa http://mosesofegypt.net/ http://twitter.com/mosessaur Screencast of unit testing Entity Framework Related Links GuestPost: Introduction to Mocking GuesPost: Typemock Isolator – Much more than an Isolation framework

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Code Contracts: Hiding ContractException

- by DigiMortal

It’s time to move on and improve my randomizer I wrote for an example of static checking of code contracts. In this posting I will modify contracts and give some explanations about pre-conditions and post-conditions. Also I will show you how to avoid ContractExceptions and how to replace them with your own exceptions. As a first thing let’s take a look at my randomizer. public class Randomizer { public static int GetRandomFromRange(int min, int max) { var rnd = new Random(); return rnd.Next(min, max); } public static int GetRandomFromRangeContracted(int min, int max) { Contract.Requires(min < max, "Min must be less than max"); var rnd = new Random(); return rnd.Next(min, max); } } We have some problems here. We need contract for method output and we also need some better exception handling mechanism. As ContractException as type is hidden from us we have to switch from ContractException to some other Exception type that we can catch. Adding post-condition Pre-conditions are contracts for method’s input interface. Read it as follows: pre-conditions make sure that all conditions for method’s successful run are met. Post-conditions are contracts for output interface of method. So, post-conditions are for output arguments and return value. My code misses the post-condition that checks return value. Return value in this case must be greater or equal to minimum value and less or equal to maximum value. To make sure that method can run only the correct value I added call to Contract.Ensures() method. public static int GetRandomFromRangeContracted(int min, int max) { Contract.Requires(min < max, "Min must be less than max"); Contract.Ensures( Contract.Result<int>() >= min && Contract.Result<int>() <= max, "Return value is out of range" ); var rnd = new Random(); return rnd.Next(min, max); } I think that the line I added does not need any further comments. Avoiding ContractException for input interface ContractException lives in hidden namespace and we cannot see it at design time. But it is common exception type for all contract exceptions that we do not switch over to some other type. The case of Contract.Requires() method is simple: we can tell it what kind of exception we need if something goes wrong with contract it ensures. public static int GetRandomFromRangeContracted(int min, int max) { Contract.Requires<ArgumentOutOfRangeException>( min < max, "Min must be less than max" ); Contract.Ensures( Contract.Result<int>() >= min && Contract.Result<int>() <= max, "Return value is out of range" ); var rnd = new Random(); return rnd.Next(min, max); } Now, if we violate the input interface contract giving min value that is not less than max value we get ArgumentOutOfRangeException. Avoiding ContractException for output interface Output interface is more complex to control. We cannot give exception type there and hope that this type of exception will be thrown if something goes wrong. Instead we have to use delegate that gathers information about problem and throws the exception we expect to be thrown. From documentation you can find the following example about the delegate I mentioned. Contract.ContractFailed += (sender, e) => { e.SetHandled(); e.SetUnwind(); // cause code to abort after event Assert.Fail(e.FailureKind.ToString() + ":" + e.DebugMessage); }; We can use this delegate to throw the Exception. Let’s move the code to separate method too. Here is our method that uses now ContractException hiding. public static int GetRandomFromRangeContracted(int min, int max) { Contract.Requires(min < max, "Min must be less than max"); Contract.Ensures( Contract.Result<int>() >= min && Contract.Result<int>() <= max, "Return value is out of range" ); Contract.ContractFailed += Contract_ContractFailed; var rnd = new Random(); return rnd.Next(min, max)+1000; } And here is the delegate that creates exception. public static void Contract_ContractFailed(object sender, ContractFailedEventArgs e) { e.SetHandled(); e.SetUnwind(); throw new Exception(e.FailureKind.ToString() + ":" + e.Message); } Basically we can do in this delegate whatever we like to do with output interface errors. We can even introduce our own contract exception type. As you can see later then ContractFailed event is very useful at unit testing.

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Handy ASP.NET MVC 2 Extension Methods – Where am I?

- by Bobby Diaz

Have you ever needed to detect what part of the application is currently being viewed? This might be a bigger issue if you write a lot of shared/partial views or custom display or editor templates. Another scenario, which is the one I encountered when I first started down this path, is when you have some type of menu and you’d like to be able to determine which item represents the current page so you can highlight it in some way. A simple example is the menu that is created as part of the default ASP.NET MVC 2 Application template. <div id="menucontainer"> <ul id="menu"> <li><%= Html.ActionLink("Home", "Index", "Home") %></li> <li><%= Html.ActionLink("About", "About", "Home") %></li> </ul> </div> The part that got me at first, however, was the following entry in the default style sheet (Site.css): ul#menu li.selected a { background-color: #fff; color: #000; } I assumed that the .selected class would automatically get applied to the active menu item. After trying a few different things, including the MvcContrib MenuBuilder, I decided to write my own extension methods so I would have more control over the output. First, I needed a way to determine what view the user has navigated to based on the requested URL and route configuration. Now, I am sure there are many ways to do this, but this is what I came up with: public static class RequestExtensions { public static bool IsCurrentRoute(this RequestContext context, String areaName, String controllerName, params String[] actionNames) { var routeData = context.RouteData; var routeArea = routeData.DataTokens["area"] as String; var current = false; if ( ((String.IsNullOrEmpty(routeArea) && String.IsNullOrEmpty(areaName)) || (routeArea == areaName)) && ((String.IsNullOrEmpty(controllerName)) || (routeData.GetRequiredString("controller") == controllerName)) && ((actionNames == null) || actionNames.Contains(routeData.GetRequiredString("action"))) ) { current = true; } return current; } // additional overloads omitted... } With that in place, I was able to write several UrlHelper methods that check if the supplied values map to the current view. public static class UrlExtensions { public static bool IsCurrent(this UrlHelper urlHelper, String areaName, String controllerName, params String[] actionNames) { return urlHelper.RequestContext.IsCurrentRoute(areaName, controllerName, actionNames); } public static string Selected(this UrlHelper urlHelper, String areaName, String controllerName, params String[] actionNames) { return urlHelper.IsCurrent(areaName, controllerName, actionNames) ? "selected" : String.Empty; } // additional overloads omitted... } Now I can re-work the original menu to utilize these new methods. Note: be sure to import the proper namespace so the extension methods become available inside your views! <div id="menucontainer"> <ul id="menu"> <li class="<%= Url.Selected(null, "Home", "Index") %>"> <%= Html.ActionLink("Home", "Index", "Home")%></li> <li class="<%= Url.Selected(null, "Home", "About") %>"> <%= Html.ActionLink("About", "About", "Home")%></li> </ul> </div> If we take it one step further, we can clean up the markup even more. Check out the Html.ActionMenuItem() extension method and the refined menu: public static class HtmlExtensions { public static MvcHtmlString ActionMenuItem(this HtmlHelper htmlHelper, String linkText, String actionName, String controllerName) { var html = new StringBuilder("<li"); if ( htmlHelper.ViewContext.RequestContext .IsCurrentRoute(null, controllerName, actionName) ) { html.Append(" class=\"selected\""); } html.Append(">") .Append(htmlHelper.ActionLink(linkText, actionName, controllerName)) .Append("</li>"); return MvcHtmlString.Create(html.ToString()); } // additional overloads omitted... } <div id="menucontainer"> <ul id="menu"> <%= Html.ActionMenuItem("Home", "Index", "Home") %> <%= Html.ActionMenuItem("About", "About", "Home") %> </ul> </div> Which generates the following HTML: <div id="menucontainer"> <ul id="menu"> <li class="selected"><a href="/">Home</a></li> <li><a href="/Home/About">About</a></li> </ul> </div> I have created a codepaste of these extension methods if you are interested in using them in your own projects. Enjoy!

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Tween Animation Cannot Start

- by David Dimalanta

Do you have any reasons why my tween code didn't run or work? I already add the tween engine onto the library folder under LibGDX project folder and "Order and Export" it under Java Build Path at the Properties menu. My first two classes ran correctly and workly but my third class didn't work. Here's the sequence: First class is the first screen. Fade animation works on the company's logo. Second class is the second screen. Fade animation for the loading screen works. Third class is the third screen. After the second screen, now calls for the third screen. Animation stopped or won't run since I want the black screen to fade out at the start when the menu is here. Can you check if I did right? Look carefully by comment lines for explanation. //-----[ Animation Setup ]----- Tween.registerAccessor(Sprite.class, new Tween_Animation()); // --> Tween_Animation.java Tween_Manager = new TweenManager(); // --> I initialized it the TweenManager and seems okay. cb_start = new TweenCallback() // --> I'll use this when I choose START and the menu will fade in black. { @Override public void onEvent(int arg0, BaseTween<?> arg1) { goTo(); } }; Tween // --> This is where I focused the problem. .to(black_Sprite, Tween_Animation.ALPHA, 3f) .target(1) .ease(TweenEquations.easeInQuad) .repeatYoyo(200, 2.5f) // --> I set the repeat for 200 times when I noticed that the animation won't work! .start(Tween_Manager);

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Editing Routes in ASP.NET MVC

- by imran_ku07

Introduction : Phil Haack's had written two great articles about Editable Routes, Editable Routes or Editable Routes Using App_Code.These Article are great. But if you not need to unit test your Routes and don't care about restart Application Domian during editing your Routes then global.asax file is the fastest and easiest to achieve the same. In this Article I will use Global.asax file instead of Global.asax.cs file for defining Routes and you will also see how this whole process will works. Description : You just need to Cut (or Copy) the code inside Global.asax.cs and paste it in Global.asax inside runat server tag. You can simply do this by cutting the code of Global.asax.cs, and paste it inside Global.asax, Easy and quick ,Now you can change Global.asax without compiling the application. How this works : I think it is worth here to see what is happening here. Actually, ASP.NET will use Global.asax file to create a class named global_asax within ASP namespace and place all the code in Global.asax inside the class global_asax class which is created at runtime, namespace ASP { public class global_asax: NerdDinner.MvcApplication { //Any definitions defined in Global.asax like Application_Start method } } Which inherits from class defined in Application tag, <%@ Application Codebehind="Global.asax.cs" Inherits="NerdDinner.MvcApplication" Language="C#" %> Actually ASP.NET creates a pool of application objects of this class, which varies from 1 to 100. Every request take one of these application objects to a serve incoming requests. After receiving an application object then it will call application specific events, like Application_Start(for only firstRequest), Application_BeginRequest(for every request), and so on. Therefore if these methods are defined in global_asax class then ASP.NET will call these method from global_asax, if not then it will use base class methods may be defined in Global.asax.cs(the concept known as shadowing or hiding). Summary : In this article, I showed how easily and quickly you can make your Routes Editable. But also note that any change in global.asax results in Application Domain restart and this technique also makes your Route Unit Test difficult.

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Dynamic XAP loading in Task-It - Part 1

Download Source Code NOTE 1: The source code provided is running against the RC versions of Silverlight 4 and VisualStudio 2010, so you will need to update to those bits to run it. NOTE 2: After downloading the source, be sure to set the .Web project as the StartUp Project, and Default.aspx as the Start Page In my MEF into post, MEF to the rescue in Task-It, I outlined a couple of issues I was facing and explained why I chose MEF (the Managed Extensibility Framework) to solve these issues. Other posts to check out There are a few other resources out there around dynamic XAP loading that you may want to review (by the way, Glenn Block is the main dude when it comes to MEF): Glenn Blocks 3-part series on a dynamically loaded dashboard Glenn and John Papas Silverlight TV video on dynamic xap loading These provide some great info, but didnt exactly cover the scenario I wanted to achieve in Task-Itand that is dynamically loading each of the apps pages the first time the user enters a page. The code In the code I provided for download above, I created a simple solution that shows the technique I used for dynamic XAP loading in Task-It, but without all of the other code that surrounds it. Taking all that other stuff away should make it easier to grasp. Having said that, there is still a fair amount of code involved. I am always looking for ways to make things simpler, and to achieve the desired result with as little code as possible, so if I find a better/simpler way I will blog about it, but for now this technique works for me. When I created this solution I started by creating a new Silverlight Navigation Application called DynamicXAP Loading. I then added the following line to my UriMappings in MainPage.xaml: <uriMapper:UriMapping Uri="/{assemblyName};component/{path}" MappedUri="/{assemblyName};component/{path}"/> In the section of MainPage.xaml that produces the page links in the upper right, I kept the Home link, but added a couple of new ones (page1 and page 2). These are the pages that will be dynamically (lazy) loaded: <StackPanel x:Name="LinksStackPanel" Style="{StaticResource LinksStackPanelStyle}"> <HyperlinkButton Style="{StaticResource LinkStyle}" NavigateUri="/Home" TargetName="ContentFrame" Content="home"/> <Rectangle Style="{StaticResource DividerStyle}"/> <HyperlinkButton Style="{StaticResource LinkStyle}" Content="page 1" Command="{Binding NavigateCommand}" CommandParameter="{Binding ModulePage1}"/> <Rectangle Style="{StaticResource DividerStyle}"/> <HyperlinkButton Style="{StaticResource LinkStyle}" Content="page 2" Command="{Binding NavigateCommand}" CommandParameter="{Binding ModulePage2}"/> </StackPanel> In App.xaml.cs I added a bit of MEF code. In Application_Startup I call a method called InitializeContainer, which creates a PackageCatalog (a MEF thing), then I create a CompositionContainer and pass it to the CompositionHost.Initialize method. This is boiler-plate MEF stuff that allows you to do 'composition' and import 'packages'. You're welcome to do a bit more MEF research on what is happening here if you'd like, but for the purpose of this example you can just trust that it works. :-) private void Application_Startup(object sender, StartupEventArgs e) { InitializeContainer(); this.RootVisual = new MainPage(); } private static void InitializeContainer() { var catalog = new PackageCatalog(); catalog.AddPackage(Package.Current); var container = new CompositionContainer(catalog); container.ComposeExportedValue(catalog); CompositionHost.Initialize(container); } Infrastructure In the sample code you'll notice that there is a project in the solution called DynamicXAPLoading.Infrastructure. This is simply a Silverlight Class Library project that I created just to move stuff I considered application 'infrastructure' code into a separate place, rather than cluttering the main Silverlight project (DynamicXapLoading). I did this same thing in Task-It, as the amount of this type of code was starting to clutter up the Silverlight project, and it just seemed to make sense to move things like Enums, Constants and the like off to a separate place. In the DynamicXapLoading.Infrastructure project you'll see 3 classes: Enums - There is only one enum in here called ModuleEnum. We'll use these later. PageMetadata - We will use this class later to add metadata to a new dynamically loaded project. ViewModelBase - This is simply a base class for view models that we will use in this, as well as future samples. As mentioned in my MVVM post, I will be using the MVVM pattern throughout my code for reasons detailed in the post. By the way, the ViewModelExtension class in there allows me to do strongly-typed property changed notification, so rather than OnPropertyChanged("MyProperty"), I can do this.OnPropertyChanged(p => p.MyProperty). It's just a less error-prown approach, because if you don't spell "MyProperty" correctly using the first method, nothing will break, it just won't work. Adding a new page We currently have a couple of pages that are being dynamically (lazy) loaded, but now let's add a third page. 1. First, create a new Silverlight Application project: In this example I call it Page3. In the future you may prefer to use a different name, like DynamicXAPLoading.Page3, or even DynamicXAPLoading.Modules.Page3. It can be whatever you want. In my Task-It application I used the latter approach (with 'Modules' in the name). I do think of these application as 'modules', but Prism uses the same term, so some folks may not like that. Use whichever naming convention you feel is appropriate, but for now Page3 will do. When you change the name to Page3 and click OK, you will be presented with the Add New Project dialog: It is important that you leave the 'Host the Silverlight application in a new or existing Web site in the solution' checked, and the .Web project will be selected in the dropdown below. This will create the .xap file for this project under ClientBin in the .Web project, which is where we want it. 2. Uncheck the 'Add a test page that references the application' checkbox, and leave everything else as is. 3. Once the project is created, you can delete App.xaml and MainPage.xaml. 4. You will need to add references your new project to the following: DynamicXAPLoading.Infrastructure.dll (this is a Project reference) DynamicNavigation.dll (this is in the Libs directory under the DynamicXAPLoading project) System.ComponentModel.Composition.dll System.ComponentModel.Composition.Initialization.dll System.Windows.Controls.Navigation.dll If you have installed the latest RC bits you will find the last 3 dll's under the .NET tab in the Add Referenced dialog. They live in the following location, or if you are on a 64-bit machine like me, it will be Program Files (x86). C:\Program Files\Microsoft SDKs\Silverlight\v4.0\Libraries\Client Now let's create some UI for our new project. 5. First, create a new Silverlight User Control called Page3.dyn.xaml 6. Paste the following code into the xaml: <dyn:DynamicPageShim xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:dyn="clr-namespace:DynamicNavigation;assembly=DynamicNavigation" xmlns:my="clr-namespace:Page3;assembly=Page3"> <my:Page3Host /> </dyn:DynamicPageShim> This is just a 'shim', part of David Poll's technique for dynamic loading. 7. Expand the icon next to Page3.dyn.xaml and delete the code-behind file (Page3.dyn.xaml.cs). 8. Next we will create a control that will 'host' our page. Create another Silverlight User Control called Page3Host.xaml and paste in the following XAML: <dyn:DynamicPage x:Class="Page3.Page3Host" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:dyn="clr-namespace:DynamicNavigation;assembly=DynamicNavigation" xmlns:Views="clr-namespace:Page3.Views" mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="400" Title="Page 3"> <Views:Page3/> </dyn:DynamicPage> 9. Now paste the following code into the code-behind for this control: using DynamicXAPLoading.Infrastructure; namespace Page3 { [PageMetadata(NavigateUri = "/Page3;component/Page3.dyn.xaml", Module = Enums.Page3)] public partial class Page3Host { public Page3Host() { InitializeComponent(); } } } Notice that we are now using that PageMetadata custom attribute class that we created in the Infrastructure project, and setting its two properties. NavigateUri - This tells it that the assembly is called Page3 (with a slash beforehand), and the page we want to load is Page3.dyn.xaml...our 'shim'. That line we added to the UriMapper in MainPage.xaml will use this information to load the page. Module - This goes back to that ModuleEnum class in our Infrastructure project. However, setting the Module to ModuleEnum.Page3 will cause a compilation error, so... 10. Go back to that Enums.cs under the Infrastructure project and add a 3rd entry for Page3: public enum ModuleEnum { Page1, Page2, Page3 } 11. Now right-click on the Page3 project and add a folder called Views. 12. Right-click on the Views folder and create a new Silverlight User Control called Page3.xaml. We won't bother creating a view model for this User Control as I did in the Page 1 and Page 2 projects, just for the sake of simplicity. Feel free to add one if you'd like though, and copy the code from one of those other projects. Right now those view models aren't really doing anything anyway...though they will in my next post. :-) 13. Now let's replace the xaml for Page3.xaml with the following: <dyn:DynamicPage x:Class="Page3.Views.Page3" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:dyn="clr-namespace:DynamicNavigation;assembly=DynamicNavigation" mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="400" Style="{StaticResource PageStyle}"> <Grid x:Name="LayoutRoot"> <ScrollViewer x:Name="PageScrollViewer" Style="{StaticResource PageScrollViewerStyle}"> <StackPanel x:Name="ContentStackPanel"> <TextBlock x:Name="HeaderText" Style="{StaticResource HeaderTextStyle}" Text="Page 3"/> <TextBlock x:Name="ContentText" Style="{StaticResource ContentTextStyle}" Text="Page 3 content"/> </StackPanel> </ScrollViewer> </Grid> </dyn:DynamicPage> 14. And in the code-behind remove the inheritance from UserControl, so it should look like this: namespace Page3.Views { public partial class Page3 { public Page3() { InitializeComponent(); } } } One thing you may have noticed is that the base class for the last two User Controls we created is DynamicPage. Once again, we are using the infrastructure that David Poll created. 15. OK, a few last things. We need a link on our main page so that we can access our new page. In MainPage.xaml let's update our links to look like this: <StackPanel x:Name="LinksStackPanel" Style="{StaticResource LinksStackPanelStyle}"> <HyperlinkButton Style="{StaticResource LinkStyle}" NavigateUri="/Home" TargetName="ContentFrame" Content="home"/> <Rectangle Style="{StaticResource DividerStyle}"/> <HyperlinkButton Style="{StaticResource LinkStyle}" Content="page 1" Command="{Binding NavigateCommand}" CommandParameter="{Binding ModulePage1}"/> <Rectangle Style="{StaticResource DividerStyle}"/> <HyperlinkButton Style="{StaticResource LinkStyle}" Content="page 2" Command="{Binding NavigateCommand}" CommandParameter="{Binding ModulePage2}"/> <Rectangle Style="{StaticResource DividerStyle}"/> <HyperlinkButton Style="{StaticResource LinkStyle}" Content="page 3" Command="{Binding NavigateCommand}" CommandParameter="{Binding ModulePage3}"/> </StackPanel> 16. Next, we need to add the following at the bottom of MainPageViewModel in the ViewModels directory of our DynamicXAPLoading project: public ModuleEnum ModulePage3 { get { return ModuleEnum.Page3; } } 17. And at last, we need to add a case for our new page to the switch statement in MainPageViewModel: switch (module) { case ModuleEnum.Page1: DownloadPackage("Page1.xap"); break; case ModuleEnum.Page2: DownloadPackage("Page2.xap"); break; case ModuleEnum.Page3: DownloadPackage("Page3.xap"); break; default: break; } Now fire up the application and click the page 1, page 2 and page 3 links. What you'll notice is that there is a 2-second delay the first time you hit each page. That is because I added the following line to the Navigate method in MainPageViewModel: Thread.Sleep(2000); // Simulate a 2 second initial loading delay The reason I put this in there is that I wanted to simulate a delay the first time the page loads (as the .xap is being downloaded from the server). You'll notice that after the first hit to the page though that there is no delay...that's because the .xap has already been downloaded. Feel free to comment out this 2-second delay, or remove it if you'd like. I just wanted to show how subsequent hits to the page would be quicker than the initial one. By the way, you may want to display some sort of BusyIndicator while the .xap is loading. I have that in my Task-It appplication, but for the sake of simplicity I did not include it here. In the future I'll blog about how I show and hide the BusyIndicator using events (I'm currently using the eventing framework in Prism for that, but may move to the one in the MVVM Light Toolkit some time soon). Whew, that felt like a lot of steps, but it does work quite nicely. As I mentioned earlier, I'll try to find ways to simplify the code (I'd like to get away from having things like hard-coded .xap file names) and will blog about it in the future if I find a better way. In my next post, I'll talk more about what is actually happening with the code that makes this all work.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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UnsatisfiedLinkError on xawt when running HEC-HMS.sh

- by G.Oxsen

I am a recent adopter of Linux and this problem has got me stumped. I use HEC-HMS and HEC-DSSVue for work on a regular basis. I have been using the widows versions in wine but they are really buggy. So I decided to try out the linux versions. the links below will take you to the download pages for these two programs. They are free programs for Hydrology and data management. Once I install them and attempt to run the shell file (HEC-HMS.sh for example) I get a ton of java errors that I do not understand. If I had to guess I would say that the java files in question can not be found. When I check to see if java is installed it is. Here is the output from the terminal from trying to run HEC-HMS.sh: Exception in thread "Thread-1" java.lang.UnsatisfiedLinkError: /home/smythe/HEC/hec-hms35/java/lib/i386/xawt/libmawt.so: libXtst.so.6: cannot open shared object file: No such file or directory at java.lang.ClassLoader$NativeLibrary.load(Native Method) at java.lang.ClassLoader.loadLibrary0(Unknown Source) at java.lang.ClassLoader.loadLibrary(Unknown Source) at java.lang.Runtime.load0(Unknown Source) at java.lang.System.load(Unknown Source) at java.lang.ClassLoader$NativeLibrary.load(Native Method) at java.lang.ClassLoader.loadLibrary0(Unknown Source) at java.lang.ClassLoader.loadLibrary(Unknown Source) at java.lang.Runtime.loadLibrary0(Unknown Source) at java.lang.System.loadLibrary(Unknown Source) at sun.security.action.LoadLibraryAction.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at sun.awt.NativeLibLoader.loadLibraries(Unknown Source) at sun.awt.DebugHelper.<clinit>(Unknown Source) at java.awt.Component.<clinit>(Unknown Source) at javax.swing.ImageIcon.<clinit>(Unknown Source) at hms.i.c(Unknown Source) at hms.i.b(Unknown Source) at hms.K.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Exception in thread "Thread-4" java.lang.UnsatisfiedLinkError: /home/smythe/HEC/hec-hms35/java/lib/i386/xawt/libmawt.so: libXtst.so.6: cannot open shared object file: No such file or directory at java.lang.ClassLoader$NativeLibrary.load(Native Method) at java.lang.ClassLoader.loadLibrary0(Unknown Source) at java.lang.ClassLoader.loadLibrary(Unknown Source) at java.lang.Runtime.load0(Unknown Source) at java.lang.System.load(Unknown Source) at java.lang.ClassLoader$NativeLibrary.load(Native Method) at java.lang.ClassLoader.loadLibrary0(Unknown Source) at java.lang.ClassLoader.loadLibrary(Unknown Source) at java.lang.Runtime.loadLibrary0(Unknown Source) at java.lang.System.loadLibrary(Unknown Source) at sun.security.action.LoadLibraryAction.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.awt.Toolkit.loadLibraries(Unknown Source) at java.awt.Toolkit.<clinit>(Unknown Source) at sun.print.CUPSPrinter.<clinit>(Unknown Source) at sun.print.UnixPrintServiceLookup.getDefaultPrintService(Unknown Source) at sun.print.UnixPrintServiceLookup.refreshServices(Unknown Source) at sun.print.UnixPrintServiceLookup$PrinterChangeListener.run(Unknown Source) Exception in thread "main" java.lang.NoClassDefFoundError: Could not initialize class java.awt.Toolkit at java.awt.Color.<clinit>(Unknown Source) at hms.model.l.<init>(Unknown Source) at hms.model.ProjectManager.<init>(Unknown Source) at hms.Hms.<init>(Unknown Source) at hms.Hms.main(Unknown Source) Exception in thread "Thread-2" java.lang.NoClassDefFoundError: Could not initialize class sun.print.CUPSPrinter at sun.print.UnixPrintServiceLookup.getDefaultPrintService(Unknown Source) at javax.print.PrintServiceLookup.lookupDefaultPrintService(Unknown Source) at hms.util.f.run(Unknown Source) at java.lang.Thread.run(Unknown Source) I get similar outputs when I try to run HEC-DSSVue.sh. If anyone could shed some light on a solution I would really appreciate it. The problem turned out to be that the program needed 32 bit versions of the particular dependencies.

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Mocking the Unmockable: Using Microsoft Moles with Gallio

- by Thomas Weller

Usual opensource mocking frameworks (like e.g. Moq or Rhino.Mocks) can mock only interfaces and virtual methods. In contrary to that, Microsoft’s Moles framework can ‘mock’ virtually anything, in that it uses runtime instrumentation to inject callbacks in the method MSIL bodies of the moled methods. Therefore, it is possible to detour any .NET method, including non-virtual/static methods in sealed types. This can be extremely helpful when dealing e.g. with code that calls into the .NET framework, some third-party or legacy stuff etc… Some useful collected resources (links to website, documentation material and some videos) can be found in my toolbox on Delicious under this link: http://delicious.com/thomasweller/toolbox+moles A Gallio extension for Moles Originally, Moles is a part of Microsoft’s Pex framework and thus integrates best with Visual Studio Unit Tests (MSTest). However, the Moles sample download contains some additional assemblies to also support other unit test frameworks. They provide a Moled attribute to ease the usage of mole types with the respective framework (there are extensions for NUnit, xUnit.net and MbUnit v2 included with the samples). As there is no such extension for the Gallio platform, I did the few required lines myself – the resulting Gallio.Moles.dll is included with the sample download. With this little assembly in place, it is possible to use Moles with Gallio like that: [Test, Moled] public void SomeTest() { ... What you can do with it Moles can be very helpful, if you need to ‘mock’ something other than a virtual or interface-implementing method. This might be the case when dealing with some third-party component, legacy code, or if you want to ‘mock’ the .NET framework itself. Generally, you need to announce each moled type that you want to use in a test with the MoledType attribute on assembly level. For example: [assembly: MoledType(typeof(System.IO.File))] Below are some typical use cases for Moles. For a more detailed overview (incl. naming conventions and an instruction on how to create the required moles assemblies), please refer to the reference material above. Detouring the .NET framework Imagine that you want to test a method similar to the one below, which internally calls some framework method: public void ReadFileContent(string fileName) { this.FileContent = System.IO.File.ReadAllText(fileName); } Using a mole, you would replace the call to the File.ReadAllText(string) method with a runtime delegate like so: [Test, Moled] [Description("This 'mocks' the System.IO.File class with a custom delegate.")] public void ReadFileContentWithMoles() { // arrange ('mock' the FileSystem with a delegate) System.IO.Moles.MFile.ReadAllTextString = (fname => fname == FileName ? FileContent : "WrongFileName"); // act var testTarget = new TestTarget.TestTarget(); testTarget.ReadFileContent(FileName); // assert Assert.AreEqual(FileContent, testTarget.FileContent); } Detouring static methods and/or classes A static method like the below… public static string StaticMethod(int x, int y) { return string.Format("{0}{1}", x, y); } … can be ‘mocked’ with the following: [Test, Moled] public void StaticMethodWithMoles() { MStaticClass.StaticMethodInt32Int32 = ((x, y) => "uups"); var result = StaticClass.StaticMethod(1, 2); Assert.AreEqual("uups", result); } Detouring constructors You can do this delegate thing even with a class’ constructor. The syntax for this is not all too intuitive, because you have to setup the internal state of the mole, but generally it works like a charm. For example, to replace this c’tor… public class ClassWithCtor { public int Value { get; private set; } public ClassWithCtor(int someValue) { this.Value = someValue; } } … you would do the following: [Test, Moled] public void ConstructorTestWithMoles() { MClassWithCtor.ConstructorInt32 = ((@class, @value) => new MClassWithCtor(@class) {ValueGet = () => 99}); var classWithCtor = new ClassWithCtor(3); Assert.AreEqual(99, classWithCtor.Value); } Detouring abstract base classes You can also use this approach to ‘mock’ abstract base classes of a class that you call in your test. Assumed that you have something like that: public abstract class AbstractBaseClass { public virtual string SaySomething() { return "Hello from base."; } } public class ChildClass : AbstractBaseClass { public override string SaySomething() { return string.Format( "Hello from child. Base says: '{0}'", base.SaySomething()); } } Then you would set up the child’s underlying base class like this: [Test, Moled] public void AbstractBaseClassTestWithMoles() { ChildClass child = new ChildClass(); new MAbstractBaseClass(child) { SaySomething = () => "Leave me alone!" } .InstanceBehavior = MoleBehaviors.Fallthrough; var hello = child.SaySomething(); Assert.AreEqual("Hello from child. Base says: 'Leave me alone!'", hello); } Setting the moles behavior to a value of MoleBehaviors.Fallthrough causes the ‘original’ method to be called if a respective delegate is not provided explicitly – here it causes the ChildClass’ override of the SaySomething() method to be called. There are some more possible scenarios, where the Moles framework could be of much help (e.g. it’s also possible to detour interface implementations like IEnumerable<T> and such…). One other possibility that comes to my mind (because I’m currently dealing with that), is to replace calls from repository classes to the ADO.NET Entity Framework O/R mapper with delegates to isolate the repository classes from the underlying database, which otherwise would not be possible… Usage Since Moles relies on runtime instrumentation, mole types must be run under the Pex profiler. This only works from inside Visual Studio if you write your tests with MSTest (Visual Studio Unit Test). While other unit test frameworks generally can be used with Moles, they require the respective tests to be run via command line, executed through the moles.runner.exe tool. A typical test execution would be similar to this: moles.runner.exe <mytests.dll> /runner:<myframework.console.exe> /args:/<myargs> So, the moled test can be run through tools like NCover or a scripting tool like MSBuild (which makes them easy to run in a Continuous Integration environment), but they are somewhat unhandy to run in the usual TDD workflow (which I described in some detail here). To make this a bit more fluent, I wrote a ReSharper live template to generate the respective command line for the test (it is also included in the sample download – moled_cmd.xml). - This is just a quick-and-dirty ‘solution’. Maybe it makes sense to write an extra Gallio adapter plugin (similar to the many others that are already provided) and include it with the Gallio download package, if there’s sufficient demand for it. As of now, the only way to run tests with the Moles framework from within Visual Studio is by using them with MSTest. From the command line, anything with a managed console runner can be used (provided that the appropriate extension is in place)… A typical Gallio/Moles command line (as generated by the mentioned R#-template) looks like that: "%ProgramFiles%\Microsoft Moles\bin\moles.runner.exe" /runner:"%ProgramFiles%\Gallio\bin\Gallio.Echo.exe" "Gallio.Moles.Demo.dll" /args:/r:IsolatedAppDomain /args:/filter:"ExactType:TestFixture and Member:ReadFileContentWithMoles" -- Note: When using the command line with Echo (Gallio’s console runner), be sure to always include the IsolatedAppDomain option, otherwise the tests won’t use the instrumentation callbacks! -- License issues As I already said, the free mocking frameworks can mock only interfaces and virtual methods. if you want to mock other things, you need the Typemock Isolator tool for that, which comes with license costs (Although these ‘costs’ are ridiculously low compared to the value that such a tool can bring to a software project, spending money often is a considerable gateway hurdle in real life...). The Moles framework also is not totally free, but comes with the same license conditions as the (closely related) Pex framework: It is free for academic/non-commercial use only, to use it in a ‘real’ software project requires an MSDN Subscription (from VS2010pro on). The demo solution The sample solution (VS 2008) can be downloaded from here. It contains the Gallio.Moles.dll which provides the here described Moled attribute, the above mentioned R#-template (moled_cmd.xml) and a test fixture containing the above described use case scenarios. To run it, you need the Gallio framework (download) and Microsoft Moles (download) being installed in the default locations. Happy testing…

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Sybase ASE

- by Linchi Shea

I sat in a Sybase ASE class last week for five days. Although it didn't cover the more advanced features introduced in the more recent versions of Sybase ASE, the class did touch all the basics of administering Sybase ASE. While I was successful in suppressing any urge to openly compare Sybase ASE with Microsoft SQL Server in the class, I could not help making mental notes on the differences between the two database platforms. It's always interesting to look at how two DBMS platforms that share the...(read more)

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Can static methods be called using object/instance in .NET

Ans is Yes and No Yes in C++, Java and VB.NET No in C# This is only compiler restriction in c#. You might see in some websites that we can break this restriction using reflection and delegates, but we can’t, according to my little research J I shall try to explain you… Following is code sample to break this rule using reflection, it seems that it is possible to call a static method using an object, p1 using System; namespace T { class Program { static void Main() { var p1 = new Person() { Name = "Smith" }; typeof(Person).GetMethod("TestStatMethod").Invoke(p1, new object[] { }); } class Person { public string Name { get; set; } public static void TestStatMethod() { Console.WriteLine("Hello"); } } } } but I do not think so this method is being called using p1 rather Type Name “Person”. I shall try to prove this… look at another example… Test2 has been inherited from Test1. Let’s see various scenarios… Scenario1 using System; namespace T { class Program { static void Main() { Test1 t = new Test1(); typeof(Test2).GetMethod("Method1").Invoke(t, new object[] { }); } } class Test1 { public static void Method1() { Console.WriteLine("At test1::Method1"); } } class Test2 : Test1 { public static void Method1() { Console.WriteLine("At test1::Method2"); } } } Output: At test1::Method2 Scenario2 static void Main() { Test2 t = new Test2(); typeof(Test2).GetMethod("Method1").Invoke(t, new object[] { }); } Output: At test1::Method2 Scenario3 static void Main() { Test1 t = new Test2(); typeof(Test2).GetMethod("Method1").Invoke(t, new object[] { }); } Output: At test1::Method2 In all above scenarios output is same, that means, Reflection also not considering the object what you pass to Invoke method in case of static methods. It is always considering the type which you specify in typeof(). So, what is the use passing instance to “Invoke”. Let see below sample using System; namespace T { class Program { static void Main() { typeof(Test2).GetMethod("Method1"). Invoke(null, new object[] { }); } } class Test1 { public static void Method1() { Console.WriteLine("At test1::Method1"); } } class Test2 : Test1 { public static void Method1() { Console.WriteLine("At test1::Method2"); } } } Output is At test1::Method2 I was able to call Invoke “Method1” of Test2 without any object. Yes, there no wonder here as Method1 is static. So we may conclude that static methods cannot be called using instances (only in c#) Why Microsoft has restricted it in C#? Ans: Really there Is no use calling static methods using objects because static methods are stateless. but still Java and C++ latest compilers allow calling static methods using instances. Java sample class Test { public static void main(String str[]) { Person p = new Person(); System.out.println(p.GetCount()); } } class Person { public static int GetCount() { return 100; } } Output 100 span.fullpost {display:none;}

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Insufficient permissions when calling flickr.auth.oauth.checkToken

- by Designer 17

This is a follow up on another question I had asked on stackoverflow a day or so ago. I'm working on trying to call flickr.people.getPhotos... but no matter what I do I keep getting this... jsonFlickrApi({"stat":"fail", "code":99, "message":"Insufficient permissions. Method requires read privileges; none granted."}); but if you were to look at my "Apps You're Using" page (on flickr) you'd see this. So, even though I've authorized the max permissions... flickr says I don't have any granted!? I even used flickr.auth.oauth.checkToken to double check that my access token was right, this was the value returned; jsonFlickrApi({"oauth":{"token":{"_content":"my-access-token"}, "perms":{"_content":"delete"}, "user":{"nsid":"my-user-nsid", "username":"designerseventeen", "fullname":"Designer Seventeen"}}, "stat":"ok"}) Here's how I'm attempting to call flickr.people.getPhotos... <?php // Attempt to call flickr.people.getPhotos $method = "flickr.people.getPhotos"; $format = 'json'; $nsid = 'my-user-nsid'; $sig_string = "{$api_secret}api_key{$api_key}format{$format}method{$method}user_id{$nsid}"; $api_sig = md5( $sig_string ); $flickr_call = "http://api.flickr.com/services/rest/?"; $url = "method=" . $method; $url .= "&api_key=" . $api_key; $url .= "&user_id=" . $nsid; $url .= "&format=" . $format; $url .= "&api_sig=" . $api_sig; $url = $flickr_call . $url; $results = file_get_contents( $url ); $rsp_arr = explode( '&',$results ); print "<pre>"; print_r($rsp_arr); print "</pre>"; I am officially stumped... and in need of help. Thanks!

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Configuration setting of HttpWebRequest.Timeout value

- by Michael Freidgeim

I wanted to set in configuration on client HttpWebRequest.Timeout.I was surprised, that MS doesn’t provide it as a part of .Net configuration.(Answer in http://forums.silverlight.net/post/77818.aspx thread: “Unfortunately specifying the timeout is not supported in current version. We may support it in the future release.”) I added it to appSettings section of app.config and read it in the method of My HttpWebRequestHelper class //The Method property can be set to any of the HTTP 1.1 protocol verbs: GET, HEAD, POST, PUT, DELETE, TRACE, or OPTIONS. public static HttpWebRequest PrepareWebRequest(string sUrl, string Method, CookieContainer cntnrCookies) { HttpWebRequest webRequest = WebRequest.Create(sUrl) as HttpWebRequest; webRequest.Method = Method; webRequest.ContentType = "application/x-www-form-urlencoded"; webRequest.CookieContainer = cntnrCookies; webRequest.Timeout = ConfigurationExtensions.GetAppSetting("HttpWebRequest.Timeout", 100000);//default 100sec-http://blogs.msdn.com/b/buckh/archive/2005/02/01/365127.aspx) /* //try to change - from http://www.codeproject.com/csharp/ClientTicket_MSNP9.asp webRequest.AllowAutoRedirect = false; webRequest.Pipelined = false; webRequest.KeepAlive = false; webRequest.ProtocolVersion = new Version(1,0);//protocol 1.0 works better that 1.1 ?? */ //MNF 26/5/2005 Some web servers expect UserAgent to be specified //so let's say it's IE6 webRequest.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; .NET CLR 1.1.4322)"; DebugOutputHelper.PrintHttpWebRequest(webRequest, TraceOutputHelper.LineWithTrace("")); return webRequest; }Related link:http://stackoverflow.com/questions/387247/i-need-help-setting-net-httpwebrequest-timeoutv

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Building extensions for Expression Blend 4 using MEF

- by Timmy Kokke

Introduction Although it was possible to write extensions for Expression Blend and Expression Design, it wasn’t very easy and out of the box only one addin could be used. With Expression Blend 4 it is possible to write extensions using MEF, the Managed Extensibility Framework. Until today there’s no documentation on how to build these extensions, so look thru the code with Reflector is something you’ll have to do very often. Because Blend and Design are build using WPF searching the visual tree with Snoop and Mole belong to the tools you’ll be using a lot exploring the possibilities. Configuring the extension project Extensions are regular .NET class libraries. To create one, load up Visual Studio 2010 and start a new project. Because Blend is build using WPF, choose a WPF User Control Library from the Windows section and give it a name and location. I named mine DemoExtension1. Because Blend looks for addins named *.extension.dll you’ll have to tell Visual Studio to use that in the Assembly Name. To change the Assembly Name right click your project and go to Properties. On the Application tab, add .Extension to name already in the Assembly name text field. To be able to debug this extension, I prefer to set the output path on the Build tab to the extensions folder of Expression Blend. This means that everything that used to go into the Debug folder is placed in the extensions folder. Including all referenced assemblies that have the copy local property set to false. One last setting. To be able to debug your extension you could start Blend and attach the debugger by hand. I like it to be able to just hit F5. Go to the Debug tab and add the the full path to Blend.exe in the Start external program text field. Extension Class Add a new class to the project. This class needs to be inherited from the IPackage interface. The IPackage interface can be found in the Microsoft.Expression.Extensibility namespace. To get access to this namespace add Microsoft.Expression.Extensibility.dll to your references. This file can be found in the same folder as the (Expression Blend 4 Beta) Blend.exe file. Make sure the Copy Local property is set to false in this reference. After implementing the interface the class would look something like: using Microsoft.Expression.Extensibility; namespace DemoExtension1 { public class DemoExtension1:IPackage { public void Load(IServices services) { } public void Unload() { } } } These two methods are called when your addin is loaded and unloaded. The parameter passed to the Load method, IServices services, is your main entry point into Blend. The IServices interface exposes the GetService<T> method. You will be using this method a lot. Almost every part of Blend can be accessed thru a service. For example, you can use to get to the commanding services of Blend by calling GetService<ICommandService>() or to get to the Windowing services by calling GetService<IWindowService>(). To get Blend to load the extension we have to implement MEF. (You can get up to speed on MEF on the community site or read the blog of Mr. MEF, Glenn Block.) In the case of Blend extensions, all that needs to be done is mark the class with an Export attribute and pass it the type of IPackage. The Export attribute can be found in the System.ComponentModel.Composition namespace which is part of the .NET 4 framework. You need to add this to your references. using System.ComponentModel.Composition; using Microsoft.Expression.Extensibility; namespace DemoExtension1 { [Export(typeof(IPackage))] public class DemoExtension1:IPackage { Blend is able to find your addin now. Adding UI The addin doesn’t do very much at this point. The WPF User Control Library came with a UserControl so lets use that in this example. I just drop a Button and a TextBlock onto the surface of the control to have something to show in the demo. To get the UserControl to work in Blend it has to be registered with the WindowService. Call GetService<IWindowService>() on the IServices interface to get access to the windowing services. The UserControl will be used in Blend on a Palette and has to be registered to enable it. This is done by calling the RegisterPalette on the IWindowService interface and passing it an identifier, an instance of the UserControl and a caption for the palette. public void Load(IServices services) { IWindowService windowService = services.GetService<IWindowService>(); UserControl1 uc = new UserControl1(); windowService.RegisterPalette("DemoExtension", uc, "Demo Extension"); } After hitting F5 to start debugging Expression Blend will start. You should be able to find the addin in the Window menu now. Activating this window will show the “Demo Extension” palette with the UserControl, style according to the settings of Blend. Now what? Because little is publicly known about how to access different parts of Blend adding breakpoints in Debug mode and browsing thru objects using the Quick Watch feature of Visual Studio is something you have to do very often. This demo extension can be used for that purpose very easily. Add the click event handler to the button on the UserControl. Change the contructor to take the IServices interface and store this in a field. Set a breakpoint in the Button_Click method. public partial class UserControl1 : UserControl { private readonly IServices _services; public UserControl1(IServices services) { _services = services; InitializeComponent(); } private void button1_Click(object sender, RoutedEventArgs e) { } } Change the call to the constructor in the load method and pass it the services property. public void Load(IServices services) { IWindowService service = services.GetService<IWindowService>(); UserControl1 uc = new UserControl1(services); service.RegisterPalette("DemoExtension", uc, "Demo Extension"); } Hit F5 to compile and start Blend. Got to the window menu and start show the addin. Click on the button to hit the breakpoint. Now place the carrot text _services text in the code window and hit Shift+F9 to show the Quick Watch window. Now start exploring and discovering where to find everything you need. More Information The are no official resources available yet. Microsoft has released one extension for expression Blend that is very useful as a reference, the Microsoft Expression Blend® Add-in Preview for Windows® Phone. This will install a .extension.dll file in the extension folder of Blend. You can load this file with Reflector and have a peek at how Microsoft is building his addins. Conclusion I hope this gives you something to get started building extensions for Expression Blend. Until Microsoft releases the final version, which hopefully includes more information about building extensions, we’ll have to work on documenting it in the community.

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Independence Day for Software Components – Loosening Coupling by Reducing Connascence

- by Brian Schroer

Today is Independence Day in the USA, which got me thinking about loosely-coupled “independent” software components. I was reminded of a video I bookmarked quite a while ago of Jim Weirich’s “Grand Unified Theory of Software Design” talk at MountainWest RubyConf 2009. I finally watched that video this morning. I highly recommend it. In the video, Jim talks about software connascence. The dictionary definition of connascence (con-NAY-sense) is: 1. The common birth of two or more at the same time 2. That which is born or produced with another. 3. The act of growing together. The brief Wikipedia page about Connascent Software Components says that: Two software components are connascent if a change in one would require the other to be modified in order to maintain the overall correctness of the system. Connascence is a way to characterize and reason about certain types of complexity in software systems. The term was introduced to the software world in Meilir Page-Jones’ 1996 book “What Every Programmer Should Know About Object-Oriented Design”. The middle third of that book is the author’s proposed graphical notation for describing OO designs. UML became the standard about a year later, so a revised version of the book was published in 1999 as “Fundamentals of Object-Oriented Design in UML”. Weirich says that the third part of the book, in which Page-Jones introduces the concept of connascence “is worth the price of the entire book”. (The price of the entire book, by the way, is not much – I just bought a used copy on Amazon for $1.36, so that was a pretty low-risk investment. I’m looking forward to getting the book and learning about connascence from the original source.) Meanwhile, here’s my summary of Weirich’s summary of Page-Jones writings about connascence: The stronger the form of connascence, the more difficult and costly it is to change the elements in the relationship. Some of the connascence types, ordered from weak to strong are: Connascence of Name Connascence of name is when multiple components must agree on the name of an entity. If you change the name of a method or property, then you need to change all references to that method or property. Duh. Connascence of name is unavoidable, assuming your objects are actually used. My main takeaway about connascence of name is that it emphasizes the importance of giving things good names so you don’t need to go changing them later. Connascence of Type Connascence of type is when multiple components must agree on the type of an entity. I assume this is more of a problem for languages without compilers (especially when used in apps without tests). I know it’s an issue with evil JavaScript type coercion. Connascence of Meaning Connascence of meaning is when multiple components must agree on the meaning of particular values, e.g that “1” means normal customer and “2” means preferred customer. The solution to this is to use constants or enums instead of “magic” strings or numbers, which reduces the coupling by changing the connascence form from “meaning” to “name”. Connascence of Position Connascence of positions is when multiple components must agree on the order of values. This refers to methods with multiple parameters, e.g.: eMailer.Send("[email protected]", "[email protected]", "Your order is complete", "Order completion notification"); The more parameters there are, the stronger the connascence of position is between the component and its callers. In the example above, it’s not immediately clear when reading the code which email addresses are sender and receiver, and which of the final two strings are subject vs. body. Connascence of position could be improved to connascence of type by replacing the parameter list with a struct or class. This “introduce parameter object” refactoring might be overkill for a method with 2 parameters, but would definitely be an improvement for a method with 10 parameters. This points out two “rules” of connascence: The Rule of Degree: The acceptability of connascence is related to the degree of its occurrence. The Rule of Locality: Stronger forms of connascence are more acceptable if the elements involved are closely related. For example, positional arguments in private methods are less problematic than in public methods. Connascence of Algorithm Connascence of algorithm is when multiple components must agree on a particular algorithm. Be DRY – Don’t Repeat Yourself. If you have “cloned” code in multiple locations, refactor it into a common function. Those are the “static” forms of connascence. There are also “dynamic” forms, including… Connascence of Execution Connascence of execution is when the order of execution of multiple components is important. Consumers of your class shouldn’t have to know that they have to call an .Initialize method before it’s safe to call a .DoSomething method. Connascence of Timing Connascence of timing is when the timing of the execution of multiple components is important. I’ll have to read up on this one when I get the book, but assume it’s largely about threading. Connascence of Identity Connascence of identity is when multiple components must reference the entity. The example Weirich gives is when you have two instances of the “Bob” Employee class and you call the .RaiseSalary method on one and then the .Pay method on the other does the payment use the updated salary? Again, this is my summary of a summary, so please be forgiving if I misunderstood anything. Once I get/read the book, I’ll make corrections if necessary and share any other useful information I might learn. See Also: Gregory Brown: Ruby Best Practices Issue #24: Connascence as a Software Design Metric (That link is failing at the time I write this, so I had to go to the Google cache of the page.)

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SQL SERVER – Disk Space Monitoring – Detecting Low Disk Space on Server

- by Pinal Dave

A very common question I often receive is how to detect if the disk space is running low on SQL Server. There are two different ways to do the same. I personally prefer method 2 as that is very easy to use and I can use it creatively along with database name. Method 1: EXEC MASTER..xp_fixeddrives GO Above query will return us two columns, drive name and MB free. If we want to use this data in our query, we will have to create a temporary table and insert the data from this stored procedure into the temporary table and use it. Method 2: SELECT DISTINCT dovs.logical_volume_name AS LogicalName, dovs.volume_mount_point AS Drive, CONVERT(INT,dovs.available_bytes/1048576.0) AS FreeSpaceInMB FROM sys.master_files mf CROSS APPLY sys.dm_os_volume_stats(mf.database_id, mf.FILE_ID) dovs ORDER BY FreeSpaceInMB ASC GO The above query will give us three columns: drive logical name, drive letter and free space in MB. We can further modify above query to also include database name in the query as well. SELECT DISTINCT DB_NAME(dovs.database_id) DBName, dovs.logical_volume_name AS LogicalName, dovs.volume_mount_point AS Drive, CONVERT(INT,dovs.available_bytes/1048576.0) AS FreeSpaceInMB FROM sys.master_files mf CROSS APPLY sys.dm_os_volume_stats(mf.database_id, mf.FILE_ID) dovs ORDER BY FreeSpaceInMB ASC GO This will give us additional data about which database is placed on which drive. If you see a database name multiple times, it is because your database has multiple files and they are on different drives. You can modify above query one more time to even include the details of actual file location. SELECT DISTINCT DB_NAME(dovs.database_id) DBName, mf.physical_name PhysicalFileLocation, dovs.logical_volume_name AS LogicalName, dovs.volume_mount_point AS Drive, CONVERT(INT,dovs.available_bytes/1048576.0) AS FreeSpaceInMB FROM sys.master_files mf CROSS APPLY sys.dm_os_volume_stats(mf.database_id, mf.FILE_ID) dovs ORDER BY FreeSpaceInMB ASC GO The above query will now additionally include the physical file location as well. As I mentioned earlier, I prefer method 2 as I can creatively use it as per the business need. Let me know which method are you using in your production server. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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Matrix rotation wrong orientation LibGDX

- by glz

I'm having a problem with matrix rotation in libgdx. I rotate it using the method matrix.rotate(Vector3 axis, float angle) but the rotation happens in the model orientation and I need it happens in the world orientation. For example: on create() method: matrix.rotate(new Vector3(0,0,1), 45); That is ok, but after: on render() method: matrix.rotate(new Vector3(0,1,0), 1); I need it rotate in world axis.

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