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  • Backbone.js Adding Model to Collection Issue

    - by jtmgdevelopment
    I am building a test application in Backbone.js (my first app using Backbone). The app goes like this: Load Data from server "Plans" Build list of plans and show to screen There is a button to add a new plan Once new plan is added, add to collection ( do not save to server as of now ) redirect to index page and show the new collection ( includes the plan you just added) My issue is with item 5. When I save a plan, I add the model to the collection then redirect to the initial view. At this point, I fetch data from the server. When I fetch data from the server, this overwrites my collection and my added model is gone. How can I prevent this from happening? I have found a way to do this but it is definitely not the correct way at all. Below you will find my code examples for this. Thanks for the help. PlansListView View: var PlansListView = Backbone.View.extend({ tagName : 'ul', initialize : function() { _.bindAll( this, 'render', 'close' ); //reset the view if the collection is reset this.collection.bind( 'reset', this.render , this ); }, render : function() { _.each( this.collection.models, function( plan ){ $( this.el ).append( new PlansListItemView({ model: plan }).render().el ); }, this ); return this; }, close : function() { $( this.el ).unbind(); $( this.el ).remove(); } });//end NewPlanView Save Method var NewPlanView = Backbone.View.extend({ tagName : 'section', template : _.template( $( '#plan-form-template' ).html() ), events : { 'click button.save' : 'savePlan', 'click button.cancel' : 'cancel' }, intialize: function() { _.bindAll( this, 'render', 'save', 'cancel' ); }, render : function() { $( '#container' ).append( $( this.el ).html(this.template( this.model.toJSON() )) ); return this; }, savePlan : function( event ) { this.model.set({ name : 'bad plan', date : 'friday', desc : 'blah', id : Math.floor(Math.random()*11), total_stops : '2' }); this.collection.add( this.model ); app.navigate('', true ); event.preventDefault(); }, cancel : function(){} }); Router (default method): index : function() { this.container.empty(); var self = this; //This is a hack to get this to work //on default page load fetch all plans from the server //if the page has loaded ( this.plans is defined) set the updated plans collection to the view //There has to be a better way!! if( ! this.plans ) { this.plans = new Plans(); this.plans.fetch({ success: function() { self.plansListView = new PlansListView({ collection : self.plans }); $( '#container' ).append( self.plansListView.render().el ); if( self.requestedID ) self.planDetails( self.requestedID ); } }); } else { this.plansListView = new PlansListView({ collection : this.plans }); $( '#container' ).append( self.plansListView.render().el ); if( this.requestedID ) self.planDetails( this.requestedID ); } }, New Plan Route: newPlan : function() { var plan = new Plan({name: 'Cool Plan', date: 'Monday', desc: 'This is a great app'}); this.newPlan = new NewPlanView({ model : plan, collection: this.plans }); this.newPlan.render(); } FULL CODE ( function( $ ){ var Plan = Backbone.Model.extend({ defaults: { name : '', date : '', desc : '' } }); var Plans = Backbone.Collection.extend({ model : Plan, url : '/data/' }); $( document ).ready(function( e ){ var PlansListView = Backbone.View.extend({ tagName : 'ul', initialize : function() { _.bindAll( this, 'render', 'close' ); //reset the view if the collection is reset this.collection.bind( 'reset', this.render , this ); }, render : function() { _.each( this.collection.models, function( plan ){ $( this.el ).append( new PlansListItemView({ model: plan }).render().el ); }, this ); return this; }, close : function() { $( this.el ).unbind(); $( this.el ).remove(); } });//end var PlansListItemView = Backbone.View.extend({ tagName : 'li', template : _.template( $( '#list-item-template' ).html() ), events :{ 'click a' : 'listInfo' }, render : function() { $( this.el ).html( this.template( this.model.toJSON() ) ); return this; }, listInfo : function( event ) { } });//end var PlanView = Backbone.View.extend({ tagName : 'section', events : { 'click button.add-plan' : 'newPlan' }, template: _.template( $( '#plan-template' ).html() ), initialize: function() { _.bindAll( this, 'render', 'close', 'newPlan' ); }, render : function() { $( '#container' ).append( $( this.el ).html( this.template( this.model.toJSON() ) ) ); return this; }, newPlan : function( event ) { app.navigate( 'newplan', true ); }, close : function() { $( this.el ).unbind(); $( this.el ).remove(); } });//end var NewPlanView = Backbone.View.extend({ tagName : 'section', template : _.template( $( '#plan-form-template' ).html() ), events : { 'click button.save' : 'savePlan', 'click button.cancel' : 'cancel' }, intialize: function() { _.bindAll( this, 'render', 'save', 'cancel' ); }, render : function() { $( '#container' ).append( $( this.el ).html(this.template( this.model.toJSON() )) ); return this; }, savePlan : function( event ) { this.model.set({ name : 'bad plan', date : 'friday', desc : 'blah', id : Math.floor(Math.random()*11), total_stops : '2' }); this.collection.add( this.model ); app.navigate('', true ); event.preventDefault(); }, cancel : function(){} }); var AppRouter = Backbone.Router.extend({ container : $( '#container' ), routes : { '' : 'index', 'viewplan/:id' : 'planDetails', 'newplan' : 'newPlan' }, initialize: function(){ }, index : function() { this.container.empty(); var self = this; //This is a hack to get this to work //on default page load fetch all plans from the server //if the page has loaded ( this.plans is defined) set the updated plans collection to the view //There has to be a better way!! if( ! this.plans ) { this.plans = new Plans(); this.plans.fetch({ success: function() { self.plansListView = new PlansListView({ collection : self.plans }); $( '#container' ).append( self.plansListView.render().el ); if( self.requestedID ) self.planDetails( self.requestedID ); } }); } else { this.plansListView = new PlansListView({ collection : this.plans }); $( '#container' ).append( self.plansListView.render().el ); if( this.requestedID ) self.planDetails( this.requestedID ); } }, planDetails : function( id ) { if( this.plans ) { this.plansListView.close(); this.plan = this.plans.get( id ); if( this.planView ) this.planView.close(); this.planView = new PlanView({ model : this.plan }); this.planView.render(); } else{ this.requestedID = id; this.index(); } if( ! this.plans ) this.index(); }, newPlan : function() { var plan = new Plan({name: 'Cool Plan', date: 'Monday', desc: 'This is a great app'}); this.newPlan = new NewPlanView({ model : plan, collection: this.plans }); this.newPlan.render(); } }); var app = new AppRouter(); Backbone.history.start(); }); })( jQuery );

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  • Generating EF Code First model classes from an existing database

    - by Jon Galloway
    Entity Framework Code First is a lightweight way to "turn on" data access for a simple CLR class. As the name implies, the intended use is that you're writing the code first and thinking about the database later. However, I really like the Entity Framework Code First works, and I want to use it in existing projects and projects with pre-existing databases. For example, MVC Music Store comes with a SQL Express database that's pre-loaded with a catalog of music (including genres, artists, and songs), and while it may eventually make sense to load that seed data from a different source, for the MVC 3 release we wanted to keep using the existing database. While I'm not getting the full benefit of Code First - writing code which drives the database schema - I can still benefit from the simplicity of the lightweight code approach. Scott Guthrie blogged about how to use entity framework with an existing database, looking at how you can override the Entity Framework Code First conventions so that it can work with a database which was created following other conventions. That gives you the information you need to create the model classes manually. However, it turns out that with Entity Framework 4 CTP 5, there's a way to generate the model classes from the database schema. Once the grunt work is done, of course, you can go in and modify the model classes as you'd like, but you can save the time and frustration of figuring out things like mapping SQL database types to .NET types. Note that this template requires Entity Framework 4 CTP 5 or later. You can install EF 4 CTP 5 here. Step One: Generate an EF Model from your existing database The code generation system in Entity Framework works from a model. You can add a model to your existing project and delete it when you're done, but I think it's simpler to just spin up a separate project to generate the model classes. When you're done, you can delete the project without affecting your application, or you may choose to keep it around in case you have other database schema updates which require model changes. I chose to add the Model classes to the Models folder of a new MVC 3 application. Right-click the folder and select "Add / New Item..."   Next, select ADO.NET Entity Data Model from the Data Templates list, and name it whatever you want (the name is unimportant).   Next, select "Generate from database." This is important - it's what kicks off the next few steps, which read your database's schema.   Now it's time to point the Entity Data Model Wizard at your existing database. I'll assume you know how to find your database - if not, I covered that a bit in the MVC Music Store tutorial section on Models and Data. Select your database, uncheck the "Save entity connection settings in Web.config" (since we won't be using them within the application), and click Next.   Now you can select the database objects you'd like modeled. I just selected all tables and clicked Finish.   And there's your model. If you want, you can make additional changes here before going on to generate the code.   Step Two: Add the DbContext Generator Like most code generation systems in Visual Studio lately, Entity Framework uses T4 templates which allow for some control over how the code is generated. K Scott Allen wrote a detailed article on T4 Templates and the Entity Framework on MSDN recently, if you'd like to know more. Fortunately for us, there's already a template that does just what we need without any customization. Right-click a blank space in the Entity Framework model surface and select "Add Code Generation Item..." Select the Code groupt in the Installed Templates section and pick the ADO.NET DbContext Generator. If you don't see this listed, make sure you've got EF 4 CTP 5 installed and that you're looking at the Code templates group. Note that the DbContext Generator template is similar to the EF POCO template which came out last year, but with "fix up" code (unnecessary in EF Code First) removed.   As soon as you do this, you'll two terrifying Security Warnings - unless you click the "Do not show this message again" checkbox the first time. It will also be displayed (twice) every time you rebuild the project, so I checked the box and no immediate harm befell my computer (fingers crossed!).   Here's the payoff: two templates (filenames ending with .tt) have been added to the project, and they've generated the code I needed.   The "MusicStoreEntities.Context.tt" template built a DbContext class which holds the entity collections, and the "MusicStoreEntities.tt" template build a separate class for each table I selected earlier. We'll customize them in the next step. I recommend copying all the generated .cs files into your application at this point, since accidentally rebuilding the generation project will overwrite your changes if you leave them there. Step Three: Modify and use your POCO entity classes Note: I made a bunch of tweaks to my POCO classes after they were generated. You don't have to do any of this, but I think it's important that you can - they're your classes, and EF Code First respects that. Modify them as you need for your application, or don't. The Context class derives from DbContext, which is what turns on the EF Code First features. It holds a DbSet for each entity. Think of DbSet as a simple List, but with Entity Framework features turned on.   //------------------------------------------------------------------------------ // <auto-generated> // This code was generated from a template. // // Changes to this file may cause incorrect behavior and will be lost if // the code is regenerated. // </auto-generated> //------------------------------------------------------------------------------ namespace EF_CodeFirst_From_Existing_Database.Models { using System; using System.Data.Entity; public partial class Entities : DbContext { public Entities() : base("name=Entities") { } public DbSet<Album> Albums { get; set; } public DbSet<Artist> Artists { get; set; } public DbSet<Cart> Carts { get; set; } public DbSet<Genre> Genres { get; set; } public DbSet<OrderDetail> OrderDetails { get; set; } public DbSet<Order> Orders { get; set; } } } It's a pretty lightweight class as generated, so I just took out the comments, set the namespace, removed the constructor, and formatted it a bit. Done. If I wanted, though, I could have added or removed DbSets, overridden conventions, etc. using System.Data.Entity; namespace MvcMusicStore.Models { public class MusicStoreEntities : DbContext { public DbSet Albums { get; set; } public DbSet Genres { get; set; } public DbSet Artists { get; set; } public DbSet Carts { get; set; } public DbSet Orders { get; set; } public DbSet OrderDetails { get; set; } } } Next, it's time to look at the individual classes. Some of mine were pretty simple - for the Cart class, I just need to remove the header and clean up the namespace. //------------------------------------------------------------------------------ // // This code was generated from a template. // // Changes to this file may cause incorrect behavior and will be lost if // the code is regenerated. // //------------------------------------------------------------------------------ namespace EF_CodeFirst_From_Existing_Database.Models { using System; using System.Collections.Generic; public partial class Cart { // Primitive properties public int RecordId { get; set; } public string CartId { get; set; } public int AlbumId { get; set; } public int Count { get; set; } public System.DateTime DateCreated { get; set; } // Navigation properties public virtual Album Album { get; set; } } } I did a bit more customization on the Album class. Here's what was generated: //------------------------------------------------------------------------------ // // This code was generated from a template. // // Changes to this file may cause incorrect behavior and will be lost if // the code is regenerated. // //------------------------------------------------------------------------------ namespace EF_CodeFirst_From_Existing_Database.Models { using System; using System.Collections.Generic; public partial class Album { public Album() { this.Carts = new HashSet(); this.OrderDetails = new HashSet(); } // Primitive properties public int AlbumId { get; set; } public int GenreId { get; set; } public int ArtistId { get; set; } public string Title { get; set; } public decimal Price { get; set; } public string AlbumArtUrl { get; set; } // Navigation properties public virtual Artist Artist { get; set; } public virtual Genre Genre { get; set; } public virtual ICollection Carts { get; set; } public virtual ICollection OrderDetails { get; set; } } } I removed the header, changed the namespace, and removed some of the navigation properties. One nice thing about EF Code First is that you don't have to have a property for each database column or foreign key. In the Music Store sample, for instance, we build the app up using code first and start with just a few columns, adding in fields and navigation properties as the application needs them. EF Code First handles the columsn we've told it about and doesn't complain about the others. Here's the basic class: using System.ComponentModel; using System.ComponentModel.DataAnnotations; using System.Web.Mvc; using System.Collections.Generic; namespace MvcMusicStore.Models { public class Album { public int AlbumId { get; set; } public int GenreId { get; set; } public int ArtistId { get; set; } public string Title { get; set; } public decimal Price { get; set; } public string AlbumArtUrl { get; set; } public virtual Genre Genre { get; set; } public virtual Artist Artist { get; set; } public virtual List OrderDetails { get; set; } } } It's my class, not Entity Framework's, so I'm free to do what I want with it. I added a bunch of MVC 3 annotations for scaffolding and validation support, as shown below: using System.ComponentModel; using System.ComponentModel.DataAnnotations; using System.Web.Mvc; using System.Collections.Generic; namespace MvcMusicStore.Models { [Bind(Exclude = "AlbumId")] public class Album { [ScaffoldColumn(false)] public int AlbumId { get; set; } [DisplayName("Genre")] public int GenreId { get; set; } [DisplayName("Artist")] public int ArtistId { get; set; } [Required(ErrorMessage = "An Album Title is required")] [StringLength(160)] public string Title { get; set; } [Required(ErrorMessage = "Price is required")] [Range(0.01, 100.00, ErrorMessage = "Price must be between 0.01 and 100.00")] public decimal Price { get; set; } [DisplayName("Album Art URL")] [StringLength(1024)] public string AlbumArtUrl { get; set; } public virtual Genre Genre { get; set; } public virtual Artist Artist { get; set; } public virtual List<OrderDetail> OrderDetails { get; set; } } } The end result was that I had working EF Code First model code for the finished application. You can follow along through the tutorial to see how I built up to the finished model classes, starting with simple 2-3 property classes and building up to the full working schema. Thanks to Diego Vega (on the Entity Framework team) for pointing me to the DbContext template.

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  • CSS and HTML incoherences when declaring multiple classes

    - by Cesco
    I'm learning CSS "seriously" for the first time, but I found the way you deal with multiple CSS classes in CSS and HTML quite incoherent. For example I learned that if I want to declare multiple CSS classes with a common style applied to them, I have to write: .style1, .style2, .style3 { color: red; } Then, if I have to declare an HTML tag that has multiple classes applied to it, I have to write: <div class="style1 style2 style3"></div> And I'm asking why? From my personal point of view it would be more coherent if both could be declared by using a comma to separate each class, or if both could be declared using a space; after all IMHO we're still talking about multiple classes, in both CSS and HTML. I think that it would make more sense if I could write this to declare a div with multiple classes applied: <div class="style1, style2, style3"></div> Am I'm missing something important? Could you explain me if there's a valid reason behind these two different syntaxes?

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  • Présentation de ClassObject.js : un framework JavaScript de construction de classes, par Abraham Tewa

    Bonjour, Je vous propose de découvrir un article sur ClassObject, un framework javascript de construction de classes, développé par votre serviteur. Ce framework permet de créer simplement des classes avec des attributs et des méthodes publiques, protégées et privées, statiques (ou non), constantes (ou non), tout en prenant en charge l'héritage. Vous pouvez poster dans cette discussion vos commentaires concernant l'article ClassObject.js : un framework JavaScript de construction de classes Merci à tous....

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  • Override ToString() in your Classes

    - by psheriff
    One of the reasons I love teaching is because of the questions that I get from attendees. I was giving a presentation at DevConnections and was showing a collection of Product objects. When I hovered over the variable that contained the collection, it looked like Figure 2. As you can see in the collection, I have actual product names of my videos from www.pdsa.com/videos being displayed. To get your data to appear in the data tips you must override the ToString() method in your class. To illustrate this, take the following simple Product class shown below: public class Product{  public string ProductName { get; set; }  public int ProductId { get; set; }} This class does not have an override of the ToString() method so if you create a collection of Product objects you will end up with data tips that look like Figure 1. Below is the code I used to create a collection of Product objects. I have shortened the code in this blog, but you can get the full source code for this sample by following the instructions at the bottom of this blog entry. List<Product> coll = new List<Product>();Product prod; prod = new Product()  { ProductName = "From Zero to HTML 5 in 60 Minutes",     ProductId = 1 };coll.Add(prod);prod = new Product()   { ProductName = "Architecting Applications …",     ProductId = 2 };coll.Add(prod);prod = new Product()  { ProductName = "Introduction to Windows Phone Development",    ProductId = 3 };coll.Add(prod);prod = new Product()   { ProductName = "Architecting a Business  …",     ProductId = 4 };coll.Add(prod);......   Figure 1: Class without overriding ToString() Now, go back to the Product class and add an override of the ToString() method as shown in the code listed below: public class Product{  public string ProductName { get; set; }  public int ProductId { get; set; }   public override string ToString()  {    return ProductName;  }} In this simple sample, I am just returning the ProductName property. However, you can create a whole string of information if you wish to display more data in your data tips. Just concatenate any properties you want from your class and return that string. When you now run the application and hover over the collection object you will now see something that looks like Figure 2. Figure 2: Overriding ToString() in your Class Another place the ToString() override comes in handy is if you forget to use a DisplayMemberPath in your ListBox or ComboBox. The ToString() method is called automatically when a class is bound to a list control. Summary You should always override the ToString() method in your classes as this will help you when debugging your application. Seeing relevant data immediately in the data tip without having to drill down one more layer and maybe scroll through a complete list of properties should help speed up your development process. NOTE: You can download the sample code for this article by visiting my website at http://www.pdsa.com/downloads. Select “Tips & Tricks”, then select “Override ToString” from the drop down list.  

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  • What are the consequences of immutable classes with references to mutable classes?

    - by glenviewjeff
    I've recently begun adopting the best practice of designing my classes to be immutable per Effective Java [Bloch2008]. I have a series of interrelated questions about degrees of mutability and their consequences. I have run into situations where a (Java) class I implemented is only "internally immutable" because it uses references to other mutable classes. In this case, the class under development appears from the external environment to have state. Do any of the benefits (see below) of immutable classes hold true even by only "internally immutable" classes? Is there an accepted term for the aforementioned "internal mutability"? Wikipedia's immutable object page uses the unsourced term "deep immutability" to describe an object whose references are also immutable. Is the distinction between mutability and side-effect-ness/state important? Josh Bloch lists the following benefits of immutable classes: are simple to construct, test, and use are automatically thread-safe and have no synchronization issues do not need a copy constructor do not need an implementation of clone allow hashCode to use lazy initialization, and to cache its return value do not need to be copied defensively when used as a field make good Map keys and Set elements (these objects must not change state while in the collection) have their class invariant established once upon construction, and it never needs to be checked again always have "failure atomicity" (a term used by Joshua Bloch) : if an immutable object throws an exception, it's never left in an undesirable or indeterminate state

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  • Unit-Testing functions which have parameters of classes where source code is not accessible

    - by McMannus
    Relating to this question, I have another question regarding unit testing functions in the utility classes: Assume you have function signatures like this: public function void doSomething(InternalClass obj, InternalElement element) where InternalClass and InternalElement are both Classes which source code are not available, because they are hidden in the API. Additionally, doSomething only operates on obj and element. I thought about mocking those classes away but this option is not possible due to the fact that they do not implement an interface at all which I could use for my Mocking classes. However, I need to fill obj with defined data to test doSomething. How can this problem be solved?

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  • Best Practices in .NET XML Serialization of Complex Classes

    This article will show you XML serialization, so simply added in code, is not a magical stick. Serialization must be planned in full detail when working with complex classes, rather than expected to work by itself. Loss of planning work leads to redesign work later on, when maintaining serialization of original classes becomes too expensive or even hits the limit after which serialization of original classes is not possible without loss of data.

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  • Enjoy Playing Dozens of Classic Atari, Adventure, and Other Types of Games Directly in Your Browser

    - by Akemi Iwaya
    Would you love to play classic Atari games, journey once again with Bilbo Baggins in The Hobbit v1.0, or even try out WordStar 2.26? Then we have the perfect way to indulge in hours of browser-based fun to share with you. The Internet Archive has worked hard to put together a JavaScript port of the MESS computer software emulator and create an awesome online Historical Software Collection of classic games and software from yesteryear! When you visit the homepage, you will be able to scroll down through it for a ‘guided tour’ of the games and software currently available in the initial collection. This is what the individual homepages for each game or bit of software looks like. Keep in mind that none of the ‘Download item’ links we checked were working for us even though they are ‘shown’… Browse on over to the Internet Archive’s Historical Software Collection homepage to start having fun with all the classic games and programs. Historical Software Collection Homepage If you would like to visit the homepage for The Hobbit v1.0 directly, then use the link below. Play The Hobbit v1.0 [via The Verge]     

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  • How To Access Your eBook Collection Anywhere in the World

    - by Jason Fitzpatrick
    If you have an eBook reader it’s likely you already have a collection of eBooks you sync to your reader from your home computer. What if you’re away from home or not sitting at your computer? Learn how to download books from your personal collection anywhere in the world (or just from your backyard). You have an eBook reader, you have an eBook collection, and when you remember to sync your books to the collection on your computer everything is rosy. What about when you forget or when the syncing process for your device is a bit of a hassle? (We’re looking at you, iPad.) Today we’re going to show you how to download eBooks to your eBook reader from anywhere in the world using a cross-platform solution Latest Features How-To Geek ETC How to Use the Avira Rescue CD to Clean Your Infected PC The Complete List of iPad Tips, Tricks, and Tutorials Is Your Desktop Printer More Expensive Than Printing Services? 20 OS X Keyboard Shortcuts You Might Not Know HTG Explains: Which Linux File System Should You Choose? HTG Explains: Why Does Photo Paper Improve Print Quality? Sunrise on the Alien Desert Planet Wallpaper Add Falling Snow to Webpages with the Snowfall Extension for Opera [Browser Fun] Automatically Keep Up With the Latest Releases from Mozilla Labs in Firefox 4.0 A Look Back at 2010 Through Infographics Monitor the Weather with the Weather Forecast Extension for Opera Orbiting at the Edge of the Atmosphere Wallpaper

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  • Convert collections of enums to collection of strings and vice versa

    - by Michael Freidgeim
    Recently I needed to convert collections of  strings, that represent enum names, to collection of enums, and opposite,  to convert collections of   enums  to collection of  strings. I didn’t find standard LINQ extensions.However, in our big collection of helper extensions I found what I needed - just with different names: /// <summary> /// Safe conversion, ignore any unexpected strings/// Consider to name as Convert extension /// </summary> /// <typeparam name="EnumType"></typeparam> /// <param name="stringsList"></param> /// <returns></returns> public static List<EnumType> StringsListAsEnumList<EnumType>(this List<string> stringsList) where EnumType : struct, IComparable, IConvertible, IFormattable     { List<EnumType> enumsList = new List<EnumType>(); foreach (string sProvider in stringsList)     {     EnumType provider;     if (EnumHelper.TryParse<EnumType>(sProvider, out provider))     {     enumsList.Add(provider);     }     }     return enumsList;     }/// <summary> /// Convert each element of collection to string /// </summary> /// <typeparam name="T"></typeparam> /// <param name="objects"></param> /// <returns></returns> public static IEnumerable<string> ToStrings<T>(this IEnumerable<T> objects) {//from http://www.c-sharpcorner.com/Blogs/997/using-linq-to-convert-an-array-from-one-type-to-another.aspx return objects.Select(en => en.ToString()); }

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  • Sort Data in Windows Phone using Collection View Source

    - by psheriff
    When you write a Windows Phone application you will most likely consume data from a web service somewhere. If that service returns data to you in a sort order that you do not want, you have an easy alternative to sort the data without writing any C# or VB code. You use the built-in CollectionViewSource object in XAML to perform the sorting for you. This assumes that you can get the data into a collection that implements the IEnumerable or IList interfaces.For this example, I will be using a simple Product class with two properties, and a list of Product objects using the Generic List class. Try this out by creating a Product class as shown in the following code:public class Product {  public Product(int id, string name)   {    ProductId = id;    ProductName = name;  }  public int ProductId { get; set; }  public string ProductName { get; set; }}Create a collection class that initializes a property called DataCollection with some sample data as shown in the code below:public class Products : List<Product>{  public Products()  {    InitCollection();  }  public List<Product> DataCollection { get; set; }  List<Product> InitCollection()  {    DataCollection = new List<Product>();    DataCollection.Add(new Product(3,        "PDSA .NET Productivity Framework"));    DataCollection.Add(new Product(1,        "Haystack Code Generator for .NET"));    DataCollection.Add(new Product(2,        "Fundamentals of .NET eBook"));    return DataCollection;  }}Notice that the data added to the collection is not in any particular order. Create a Windows Phone page and add two XML namespaces to the Page.xmlns:scm="clr-namespace:System.ComponentModel;assembly=System.Windows"xmlns:local="clr-namespace:WPSortData"The 'local' namespace is an alias to the name of the project that you created (in this case WPSortData). The 'scm' namespace references the System.Windows.dll and is needed for the SortDescription class that you will use for sorting the data. Create a phone:PhoneApplicationPage.Resources section in your Windows Phone page that looks like the following:<phone:PhoneApplicationPage.Resources>  <local:Products x:Key="products" />  <CollectionViewSource x:Key="prodCollection"      Source="{Binding Source={StaticResource products},                       Path=DataCollection}">    <CollectionViewSource.SortDescriptions>      <scm:SortDescription PropertyName="ProductName"                           Direction="Ascending" />    </CollectionViewSource.SortDescriptions>  </CollectionViewSource></phone:PhoneApplicationPage.Resources>The first line of code in the resources section creates an instance of your Products class. The constructor of the Products class calls the InitCollection method which creates three Product objects and adds them to the DataCollection property of the Products class. Once the Products object is instantiated you now add a CollectionViewSource object in XAML using the Products object as the source of the data to this collection. A CollectionViewSource has a SortDescriptions collection that allows you to specify a set of SortDescription objects. Each object can set a PropertyName and a Direction property. As you see in the above code you set the PropertyName equal to the ProductName property of the Product object and tell it to sort in an Ascending direction.All you have to do now is to create a ListBox control and set its ItemsSource property to the CollectionViewSource object. The ListBox displays the data in sorted order by ProductName and you did not have to write any LINQ queries or write other code to sort the data!<ListBox    ItemsSource="{Binding Source={StaticResource prodCollection}}"   DisplayMemberPath="ProductName" />SummaryIn this blog post you learned that you can sort any data without having to change the source code of where the data comes from. Simply feed the data into a CollectionViewSource in XAML and set some sort descriptions in XAML and the rest is done for you! This comes in very handy when you are consuming data from a source where the data is given to you and you do not have control over the sorting.NOTE: You can download this article and many samples like the one shown in this blog entry at my website. http://www.pdsa.com/downloads. Select “Tips and Tricks”, then “Sort Data in Windows Phone using Collection View Source” from the drop down list.Good Luck with your Coding,Paul Sheriff** SPECIAL OFFER FOR MY BLOG READERS **We frequently offer a FREE gift for readers of my blog. Visit http://www.pdsa.com/Event/Blog for your FREE gift!

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  • The Messiest Home Offices Ever! [Image Collection]

    - by Asian Angel
    A geek’s home office is a haven to relax in along with being an extension of personal interests and hobbies. But occasionally other people will criticize your setup as being messy, unorganized, or worse…and that is just going too far! The next time someone starts in on you about your home office simply “hit them” with this collection of the messiest home offices ever and put a permanent end to their arguments. WARNING!: Some of the images in this collection come with a strong rating of N.S.F.L. (Not Safe For Lunch), so if you have a squeamish stomach then it would be best if you skip visiting the link below. Untidy Home Offices Photo Collection [via BoingBoing] 6 Start Menu Replacements for Windows 8 What Is the Purpose of the “Do Not Cover This Hole” Hole on Hard Drives? How To Log Into The Desktop, Add a Start Menu, and Disable Hot Corners in Windows 8

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  • Channel 9 Interview: Array and Collection Initializers in Visual Basic 2010 (Beth Massi, Spotty Bowl

    Ive written about collection initializers on my blog before, but I thought Id catch up with the VB Team to tell me more about how they really work. In this interview Spotty Bowles, a tester on the VB Compiler team, shows us a couple of new language features: Array and Collection Initializers. He gives us insight into how they are implemented in the compiler and best practices on how to use them in our code. Additionally, he discusses how to extend Collection Initializers with your own extension...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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  • How can I cleanly and elegantly handle data and dependancies between classes

    - by Neophyte
    I'm working on 2d topdown game in SFML 2, and need to find an elegant way in which everything will work and fit together. Allow me to explain. I have a number of classes that inherit from an abstract base that provides a draw method and an update method to all the classes. In the game loop, I call update and then draw on each class, I imagine this is a pretty common approach. I have classes for tiles, collisions, the player and a resource manager that contains all the tiles/images/textures. Due to the way input works in SFML I decided to have each class handle input (if required) in its update call. Up until now I have been passing in dependencies as needed, for example, in the player class when a movement key is pressed, I call a method on the collision class to check if the position the player wants to move to will be a collision, and only move the player if there is no collision. This works fine for the most part, but I believe it can be done better, I'm just not sure how. I now have more complex things I need to implement, eg: a player is able to walk up to an object on the ground, press a key to pick it up/loot it and it will then show up in inventory. This means that a few things need to happen: Check if the player is in range of a lootable item on keypress, else do not proceed. Find the item. Update the sprite texture on the item from its default texture to a "looted" texture. Update the collision for the item: it might have changed shape or been removed completely. Inventory needs to be updated with the added item. How do I make everything communicate? With my current system I will end up with my classes going out of scope, and method calls to each other all over the place. I could tie up all the classes in one big manager and give each one a reference to the parent manager class, but this seems only slightly better. Any help/advice would be greatly appreciated! If anything is unclear, I'm happy to expand on things.

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  • Quantifying the Performance of Garbage Collection vs. Explicit Memory Management

    - by EmbeddedProg
    I found this article here: Quantifying the Performance of Garbage Collection vs. Explicit Memory Management http://www.cs.umass.edu/~emery/pubs/gcvsmalloc.pdf In the conclusion section, it reads: Comparing runtime, space consumption, and virtual memory footprints over a range of benchmarks, we show that the runtime performance of the best-performing garbage collector is competitive with explicit memory management when given enough memory. In particular, when garbage collection has five times as much memory as required, its runtime performance matches or slightly exceeds that of explicit memory management. However, garbage collection’s performance degrades substantially when it must use smaller heaps. With three times as much memory, it runs 17% slower on average, and with twice as much memory, it runs 70% slower. Garbage collection also is more susceptible to paging when physical memory is scarce. In such conditions, all of the garbage collectors we examine here suffer order-of-magnitude performance penalties relative to explicit memory management. So, if my understanding is correct: if I have an app written in native C++ requiring 100 MB of memory, to achieve the same performance with a "managed" (i.e. garbage collector based) language (e.g. Java, C#), the app should require 5*100 MB = 500 MB? (And with 2*100 MB = 200 MB, the managed app would run 70% slower than the native app?) Do you know if current (i.e. latest Java VM's and .NET 4.0's) garbage collectors suffer the same problems described in the aforementioned article? Has the performance of modern garbage collectors improved? Thanks.

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  • Desktop Fun: Winter 2012 Wallpaper Collection [Bonus Size]

    - by Asian Angel
    The frostiest time of year is here once again and we have the perfect collection of snowy backgrounds for your favorite computer. Turn your desktop into a winter wonderland with our Winter 2012 Wallpaper collection. HTG Explains: Does Your Android Phone Need an Antivirus? How To Use USB Drives With the Nexus 7 and Other Android Devices Why Does 64-Bit Windows Need a Separate “Program Files (x86)” Folder?

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  • SQL SERVER Configure Management Data Collection in Quick Steps T-SQL Tuesday #005

    This article was written as a response to T-SQL Tuesday #005 Reporting.The three most important components of any computer and server are the CPU, Memory, and Hard disk specification. This post talks about how to get more details about these three most important components using the Management Data Collection. Management Data Collection generates the [...]...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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  • Using Query Classes With NHibernate

    - by Liam McLennan
    Even when using an ORM, such as NHibernate, the developer still has to decide how to perform queries. The simplest strategy is to get access to an ISession and directly perform a query whenever you need data. The problem is that doing so spreads query logic throughout the entire application – a clear violation of the Single Responsibility Principle. A more advanced strategy is to use Eric Evan’s Repository pattern, thus isolating all query logic within the repository classes. I prefer to use Query Classes. Every query needed by the application is represented by a query class, aka a specification. To perform a query I: Instantiate a new instance of the required query class, providing any data that it needs Pass the instantiated query class to an extension method on NHibernate’s ISession type. To query my database for all people over the age of sixteen looks like this: [Test] public void QueryBySpecification() { var canDriveSpecification = new PeopleOverAgeSpecification(16); var allPeopleOfDrivingAge = session.QueryBySpecification(canDriveSpecification); } To be able to query for people over a certain age I had to create a suitable query class: public class PeopleOverAgeSpecification : Specification<Person> { private readonly int age; public PeopleOverAgeSpecification(int age) { this.age = age; } public override IQueryable<Person> Reduce(IQueryable<Person> collection) { return collection.Where(person => person.Age > age); } public override IQueryable<Person> Sort(IQueryable<Person> collection) { return collection.OrderBy(person => person.Name); } } Finally, the extension method to add QueryBySpecification to ISession: public static class SessionExtensions { public static IEnumerable<T> QueryBySpecification<T>(this ISession session, Specification<T> specification) { return specification.Fetch( specification.Sort( specification.Reduce(session.Query<T>()) ) ); } } The inspiration for this style of data access came from Ayende’s post Do You Need a Framework?. I am sick of working through multiple layers of abstraction that don’t do anything. Have you ever seen code that required a service layer to call a method on a repository, that delegated to a common repository base class that wrapped and ORMs unit of work? I can achieve the same thing with NHibernate’s ISession and a single extension method. If you’re interested you can get the full Query Classes example source from Github.

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  • How to access java collection, just like the table in the database, having indexes and LINQ-like que

    - by Shaman
    This task occurs from time to time in my projects. I need to handle a collection of some complex elements, having different attributes, such as login, password_hash, role, etc. And, I need to be able to query that collection, just like I query a table in the database, having only partial data. For example: get all users, with role "user". Or check, if there's a user with login "root" and role "superuser". Removing items, based on same data is also needed. The first attempt I've tried is to use Google collections, Apache collections, and lambdaj. All of them have very similar preicate mechanism, but with a great disadvantage: it is based on iteration, one by one, over the collection of items, which is not good, for often used collections, containing big amounts of data. Could you please suggest me some solution? Thanks.

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  • How to Buy an SD Card: Speed Classes, Sizes, and Capacities Explained

    - by Chris Hoffman
    Memory cards are used in digital cameras, music players, smartphones, tablets, and even laptops. But not all SD cards are created equal — there are different speed classes, physical sizes, and capacities to consider. Different devices require different types of SD cards. Here are the differences you’ll need to keep in mind when picking out the right SD card for your device. Speed Class In a nutshell, not all SD cards offer the same speeds. This matters for some tasks more than it matters for others. For example, if you’re a professional photographer taking photos in rapid succession on a DSLR camera saving them in high-resolution RAW format, you’ll want a fast SD card so your camera can save them as fast as possible. A fast SD card is also important if you want to record high-resolution video and save it directly to the SD card. If you’re just taking a few photos on a typical consumer camera or you’re just using an SD card to store some media files on your smartphone, the speed isn’t as important. Manufacturers use “speed classes” to measure an SD card’s speed. The SD Association that defines the SD card standard doesn’t actually define the exact speeds associated with these classes, but they do provide guidelines. There are four different speed classes — 10, 8, 4, and 2. 10 is the fastest, while 2 is the slowest. Class 2 is suitable for standard definition video recording, while classes 4 and 6 are suitable for high-definition video recording. Class 10 is suitable for “full HD video recording” and “HD still consecutive recording.” There are also two Ultra High Speed (UHS) speed classes, but they’re more expensive and are designed for professional use. UHS cards are designed for devices that support UHS. Here are the associated logos, in order from slowest to fastest:       You’ll probably be okay with a class 4 or 6 card for typical use in a digital camera, smartphone, or tablet. Class 10 cards are ideal if you’re shooting high-resolution videos or RAW photos. Class 2 cards are a bit on the slow side these days, so you may want to avoid them for all but the cheapest digital cameras. Even a cheap smartphone can record HD video, after all. An SD card’s speed class is identified on the SD card itself. You’ll also see the speed class on the online store listing or on the card’s packaging when purchasing it. For example, in the below photo, the middle SD card is speed class 4, while the two other cards are speed class 6. If you see no speed class symbol, you have a class 0 SD card. These cards were designed and produced before the speed class rating system was introduced. They may be slower than even a class 2 card. Physical Size Different devices use different sizes of SD cards. You’ll find standard-size CD cards, miniSD cards, and microSD cards. Standard SD cards are the largest, although they’re still very small. They measure 32x24x2.1 mm and weigh just two grams. Most consumer digital cameras for sale today still use standard SD cards. They have the standard “cut corner”  design. miniSD cards are smaller than standard SD cards, measuring 21.5x20x1.4 mm and weighing about 0.8 grams. This is the least common size today. miniSD cards were designed to be especially small for mobile phones, but we now have a smaller size. microSD cards are the smallest size of SD card, measuring 15x11x1 mm and weighing just 0.25 grams. These cards are used in most cell phones and smartphones that support SD cards. They’re also used in many other devices, such as tablets. SD cards will only fit into marching slots. You can’t plug a microSD card into a standard SD card slot — it won’t fit. However, you can purchase an adapter that allows you to plug a smaller SD card into a larger SD card’s form and fit it into the appropriate slot. Capacity Like USB flash drives, hard drives, solid-state drives, and other storage media, different SD cards can have different amounts of storage. But the differences between SD card capacities don’t stop there. Standard SDSC (SD) cards are 1 MB to 2 GB in size, or perhaps 4 GB in size — although 4 GB is non-standard. The SDHC standard was created later, and allows cards 2 GB to 32 GB in size. SDXC is a more recent standard that allows cards 32 GB to 2 TB in size. You’ll need a device that supports SDHC or SDXC cards to use them. At this point, the vast majority of devices should support SDHC. In fact, the SD cards you have are probably SDHC cards. SDXC is newer and less common. When buying an SD card, you’ll need to buy the right speed class, size, and capacity for your needs. Be sure to check what your device supports and consider what speed and capacity you’ll actually need. Image Credit: Ryosuke SEKIDO on Flickr, Clive Darra on Flickr, Steven Depolo on Flickr

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  • Free C# Online Classes

    Now you can learn C language online from expert teachers of WiZiQ. These are Free Online Classes on C# which are scheduled on different timings. You can join the class as per your convenience.  Below are some of the topics which are covered in the classes:Programming with Collections in C#.NETIntroduction to Complex NumbersC++ Fundamental 2C++ ProgrammingThe recordings of these classes are also available which you can view anytime. ...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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