virtual methods - Page 219

C# 4.0: Named And Optional Arguments

- by Paulo Morgado

As part of the co-evolution effort of C# and Visual Basic, C# 4.0 introduces Named and Optional Arguments. First of all, let’s clarify what are arguments and parameters: Method definition parameters are the input variables of the method. Method call arguments are the values provided to the method parameters. In fact, the C# Language Specification states the following on §7.5: The argument list (§7.5.1) of a function member invocation provides actual values or variable references for the parameters of the function member. Given the above definitions, we can state that: Parameters have always been named and still are. Parameters have never been optional and still aren’t. Named Arguments Until now, the way the C# compiler matched method call definition arguments with method parameters was by position. The first argument provides the value for the first parameter, the second argument provides the value for the second parameter, and so on and so on, regardless of the name of the parameters. If a parameter was missing a corresponding argument to provide its value, the compiler would emit a compilation error. For this call: Greeting("Mr.", "Morgado", 42); this method: public void Greeting(string title, string name, int age) will receive as parameters: title: “Mr.” name: “Morgado” age: 42 What this new feature allows is to use the names of the parameters to identify the corresponding arguments in the form: name:value Not all arguments in the argument list must be named. However, all named arguments must be at the end of the argument list. The matching between arguments (and the evaluation of its value) and parameters will be done first by name for the named arguments and than by position for the unnamed arguments. This means that, for this method definition: public static void Method(int first, int second, int third) this call declaration: int i = 0; Method(i, third: i++, second: ++i); will have this code generated by the compiler: int i = 0; int CS$0$0000 = i++; int CS$0$0001 = ++i; Method(i, CS$0$0001, CS$0$0000); which will give the method the following parameter values: first: 2 second: 2 third: 0 Notice the variable names. Although invalid being invalid C# identifiers, they are valid .NET identifiers and thus avoiding collision between user written and compiler generated code. Besides allowing to re-order of the argument list, this feature is very useful for auto-documenting the code, for example, when the argument list is very long or not clear, from the call site, what the arguments are. Optional Arguments Parameters can now have default values: public static void Method(int first, int second = 2, int third = 3) Parameters with default values must be the last in the parameter list and its value is used as the value of the parameter if the corresponding argument is missing from the method call declaration. For this call declaration: int i = 0; Method(i, third: ++i); will have this code generated by the compiler: int i = 0; int CS$0$0000 = ++i; Method(i, 2, CS$0$0000); which will give the method the following parameter values: first: 1 second: 2 third: 1 Because, when method parameters have default values, arguments can be omitted from the call declaration, this might seem like method overloading or a good replacement for it, but it isn’t. Although methods like this: public static StreamReader OpenTextFile( string path, Encoding encoding = null, bool detectEncoding = true, int bufferSize = 1024) allow to have its calls written like this: OpenTextFile("foo.txt", Encoding.UTF8); OpenTextFile("foo.txt", Encoding.UTF8, bufferSize: 4096); OpenTextFile( bufferSize: 4096, path: "foo.txt", detectEncoding: false); The complier handles default values like constant fields taking the value and useing it instead of a reference to the value. So, like with constant fields, methods with parameters with default values are exposed publicly (and remember that internal members might be publicly accessible – InternalsVisibleToAttribute). If such methods are publicly accessible and used by another assembly, those values will be hard coded in the calling code and, if the called assembly has its default values changed, they won’t be assumed by already compiled code. At the first glance, I though that using optional arguments for “bad” written code was great, but the ability to write code like that was just pure evil. But than I realized that, since I use private constant fields, it’s OK to use default parameter values on privately accessed methods.

Read the article

Developing web apps using ASP.NET MVC 3, Razor and EF Code First - Part 1

- by shiju

In this post, I will demonstrate web application development using ASP. NET MVC 3, Razor and EF code First. This post will also cover Dependency Injection using Unity 2.0 and generic Repository and Unit of Work for EF Code First. The following frameworks will be used for this step by step tutorial. ASP.NET MVC 3 EF Code First CTP 5 Unity 2.0 Define Domain Model Let’s create domain model for our simple web application Category class public class Category { public int CategoryId { get; set; } [Required(ErrorMessage = "Name Required")] [StringLength(25, ErrorMessage = "Must be less than 25 characters")] public string Name { get; set;} public string Description { get; set; } public virtual ICollection<Expense> Expenses { get; set; } } Expense class public class Expense { public int ExpenseId { get; set; } public string Transaction { get; set; } public DateTime Date { get; set; } public double Amount { get; set; } public int CategoryId { get; set; } public virtual Category Category { get; set; } } We have two domain entities - Category and Expense. A single category contains a list of expense transactions and every expense transaction should have a Category. In this post, we will be focusing on CRUD operations for the entity Category and will be working on the Expense entity with a View Model object in the later post. And the source code for this application will be refactored over time. The above entities are very simple POCO (Plain Old CLR Object) classes and the entity Category is decorated with validation attributes in the System.ComponentModel.DataAnnotations namespace. Now we want to use these entities for defining model objects for the Entity Framework 4. Using the Code First approach of Entity Framework, we can first define the entities by simply writing POCO classes without any coupling with any API or database library. This approach lets you focus on domain model which will enable Domain-Driven Development for applications. EF code first support is currently enabled with a separate API that is runs on top of the Entity Framework 4. EF Code First is reached CTP 5 when I am writing this article. Creating Context Class for Entity Framework We have created our domain model and let’s create a class in order to working with Entity Framework Code First. For this, you have to download EF Code First CTP 5 and add reference to the assembly EntitFramework.dll. You can also use NuGet to download add reference to EEF Code First. public class MyFinanceContext : DbContext { public MyFinanceContext() : base("MyFinance") { } public DbSet<Category> Categories { get; set; } public DbSet<Expense> Expenses { get; set; } } The above class MyFinanceContext is derived from DbContext that can connect your model classes to a database. The MyFinanceContext class is mapping our Category and Expense class into database tables Categories and Expenses using DbSet<TEntity> where TEntity is any POCO class. When we are running the application at first time, it will automatically create the database. EF code-first look for a connection string in web.config or app.config that has the same name as the dbcontext class. If it is not find any connection string with the convention, it will automatically create database in local SQL Express database by default and the name of the database will be same name as the dbcontext class. You can also define the name of database in constructor of the the dbcontext class. Unlike NHibernate, we don’t have to use any XML based mapping files or Fluent interface for mapping between our model and database. The model classes of Code First are working on the basis of conventions and we can also use a fluent API to refine our model. The convention for primary key is ‘Id’ or ‘<class name>Id’. If primary key properties are detected with type ‘int’, ‘long’ or ‘short’, they will automatically registered as identity columns in the database by default. Primary key detection is not case sensitive. We can define our model classes with validation attributes in the System.ComponentModel.DataAnnotations namespace and it automatically enforces validation rules when a model object is updated or saved. Generic Repository for EF Code First We have created model classes and dbcontext class. Now we have to create generic repository pattern for data persistence with EF code first. If you don’t know about the repository pattern, checkout Martin Fowler’s article on Repository Let’s create a generic repository to working with DbContext and DbSet generics. public interface IRepository<T> where T : class { void Add(T entity); void Delete(T entity); T GetById(long Id); IEnumerable<T> All(); } RepositoryBasse – Generic Repository class public abstract class RepositoryBase<T> where T : class { private MyFinanceContext database; private readonly IDbSet<T> dbset; protected RepositoryBase(IDatabaseFactory databaseFactory) { DatabaseFactory = databaseFactory; dbset = Database.Set<T>(); } protected IDatabaseFactory DatabaseFactory { get; private set; } protected MyFinanceContext Database { get { return database ?? (database = DatabaseFactory.Get()); } } public virtual void Add(T entity) { dbset.Add(entity); } public virtual void Delete(T entity) { dbset.Remove(entity); } public virtual T GetById(long id) { return dbset.Find(id); } public virtual IEnumerable<T> All() { return dbset.ToList(); } } DatabaseFactory class public class DatabaseFactory : Disposable, IDatabaseFactory { private MyFinanceContext database; public MyFinanceContext Get() { return database ?? (database = new MyFinanceContext()); } protected override void DisposeCore() { if (database != null) database.Dispose(); } } Unit of Work If you are new to Unit of Work pattern, checkout Fowler’s article on Unit of Work . According to Martin Fowler, the Unit of Work pattern "maintains a list of objects affected by a business transaction and coordinates the writing out of changes and the resolution of concurrency problems." Let’s create a class for handling Unit of Work public interface IUnitOfWork { void Commit(); } UniOfWork class public class UnitOfWork : IUnitOfWork { private readonly IDatabaseFactory databaseFactory; private MyFinanceContext dataContext; public UnitOfWork(IDatabaseFactory databaseFactory) { this.databaseFactory = databaseFactory; } protected MyFinanceContext DataContext { get { return dataContext ?? (dataContext = databaseFactory.Get()); } } public void Commit() { DataContext.Commit(); } } The Commit method of the UnitOfWork will call the commit method of MyFinanceContext class and it will execute the SaveChanges method of DbContext class. Repository class for Category In this post, we will be focusing on the persistence against Category entity and will working on other entities in later post. Let’s create a repository for handling CRUD operations for Category using derive from a generic Repository RepositoryBase<T>. public class CategoryRepository: RepositoryBase<Category>, ICategoryRepository { public CategoryRepository(IDatabaseFactory databaseFactory) : base(databaseFactory) { } } public interface ICategoryRepository : IRepository<Category> { } If we need additional methods than generic repository for the Category, we can define in the CategoryRepository. Dependency Injection using Unity 2.0 If you are new to Inversion of Control/ Dependency Injection or Unity, please have a look on my articles at http://weblogs.asp.net/shijuvarghese/archive/tags/IoC/default.aspx. I want to create a custom lifetime manager for Unity to store container in the current HttpContext. public class HttpContextLifetimeManager<T> : LifetimeManager, IDisposable { public override object GetValue() { return HttpContext.Current.Items[typeof(T).AssemblyQualifiedName]; } public override void RemoveValue() { HttpContext.Current.Items.Remove(typeof(T).AssemblyQualifiedName); } public override void SetValue(object newValue) { HttpContext.Current.Items[typeof(T).AssemblyQualifiedName] = newValue; } public void Dispose() { RemoveValue(); } } Let’s create controller factory for Unity in the ASP.NET MVC 3 application. public class UnityControllerFactory : DefaultControllerFactory { IUnityContainer container; public UnityControllerFactory(IUnityContainer container) { this.container = container; } protected override IController GetControllerInstance(RequestContext reqContext, Type controllerType) { IController controller; if (controllerType == null) throw new HttpException( 404, String.Format( "The controller for path '{0}' could not be found" + "or it does not implement IController.", reqContext.HttpContext.Request.Path)); if (!typeof(IController).IsAssignableFrom(controllerType)) throw new ArgumentException( string.Format( "Type requested is not a controller: {0}", controllerType.Name), "controllerType"); try { controller= container.Resolve(controllerType) as IController; } catch (Exception ex) { throw new InvalidOperationException(String.Format( "Error resolving controller {0}", controllerType.Name), ex); } return controller; } } Configure contract and concrete types in Unity Let’s configure our contract and concrete types in Unity for resolving our dependencies. private void ConfigureUnity() { //Create UnityContainer IUnityContainer container = new UnityContainer() .RegisterType<IDatabaseFactory, DatabaseFactory>(new HttpContextLifetimeManager<IDatabaseFactory>()) .RegisterType<IUnitOfWork, UnitOfWork>(new HttpContextLifetimeManager<IUnitOfWork>()) .RegisterType<ICategoryRepository, CategoryRepository>(new HttpContextLifetimeManager<ICategoryRepository>()); //Set container for Controller Factory ControllerBuilder.Current.SetControllerFactory( new UnityControllerFactory(container)); } In the above ConfigureUnity method, we are registering our types onto Unity container with custom lifetime manager HttpContextLifetimeManager. Let’s call ConfigureUnity method in the Global.asax.cs for set controller factory for Unity and configuring the types with Unity. protected void Application_Start() { AreaRegistration.RegisterAllAreas(); RegisterGlobalFilters(GlobalFilters.Filters); RegisterRoutes(RouteTable.Routes); ConfigureUnity(); } Developing web application using ASP.NET MVC 3 We have created our domain model for our web application and also have created repositories and configured dependencies with Unity container. Now we have to create controller classes and views for doing CRUD operations against the Category entity. Let’s create controller class for Category Category Controller public class CategoryController : Controller { private readonly ICategoryRepository categoryRepository; private readonly IUnitOfWork unitOfWork; public CategoryController(ICategoryRepository categoryRepository, IUnitOfWork unitOfWork) { this.categoryRepository = categoryRepository; this.unitOfWork = unitOfWork; } public ActionResult Index() { var categories = categoryRepository.All(); return View(categories); } [HttpGet] public ActionResult Edit(int id) { var category = categoryRepository.GetById(id); return View(category); } [HttpPost] public ActionResult Edit(int id, FormCollection collection) { var category = categoryRepository.GetById(id); if (TryUpdateModel(category)) { unitOfWork.Commit(); return RedirectToAction("Index"); } else return View(category); } [HttpGet] public ActionResult Create() { var category = new Category(); return View(category); } [HttpPost] public ActionResult Create(Category category) { if (!ModelState.IsValid) { return View("Create", category); } categoryRepository.Add(category); unitOfWork.Commit(); return RedirectToAction("Index"); } [HttpPost] public ActionResult Delete(int id) { var category = categoryRepository.GetById(id); categoryRepository.Delete(category); unitOfWork.Commit(); var categories = categoryRepository.All(); return PartialView("CategoryList", categories); } } Creating Views in Razor Now we are going to create views in Razor for our ASP.NET MVC 3 application. Let’s create a partial view CategoryList.cshtml for listing category information and providing link for Edit and Delete operations. CategoryList.cshtml @using MyFinance.Helpers; @using MyFinance.Domain; @model IEnumerable<Category> <table> <tr> <th>Actions</th> <th>Name</th> <th>Description</th> </tr> @foreach (var item in Model) { <tr> <td> @Html.ActionLink("Edit", "Edit",new { id = item.CategoryId }) @Ajax.ActionLink("Delete", "Delete", new { id = item.CategoryId }, new AjaxOptions { Confirm = "Delete Expense?", HttpMethod = "Post", UpdateTargetId = "divCategoryList" }) </td> <td> @item.Name </td> <td> @item.Description </td> </tr> } </table> <p> @Html.ActionLink("Create New", "Create") </p> The delete link is providing Ajax functionality using the Ajax.ActionLink. This will call an Ajax request for Delete action method in the CategoryCotroller class. In the Delete action method, it will return Partial View CategoryList after deleting the record. We are using CategoryList view for the Ajax functionality and also for Index view using for displaying list of category information. Let’s create Index view using partial view CategoryList Index.chtml @model IEnumerable<MyFinance.Domain.Category> @{ ViewBag.Title = "Index"; } <h2>Category List</h2> <script src="@Url.Content("~/Scripts/jquery.unobtrusive-ajax.min.js")" type="text/javascript"></script> <div id="divCategoryList"> @Html.Partial("CategoryList", Model) </div> We can call the partial views using Html.Partial helper method. Now we are going to create View pages for insert and update functionality for the Category. Both view pages are sharing common user interface for entering the category information. So I want to create an EditorTemplate for the Category information. We have to create the EditorTemplate with the same name of entity object so that we can refer it on view pages using @Html.EditorFor(model => model) . So let’s create template with name Category. Let’s create view page for insert Category information @model MyFinance.Domain.Category @{ ViewBag.Title = "Save"; } <h2>Create</h2> <script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script> @using (Html.BeginForm()) { @Html.ValidationSummary(true) <fieldset> <legend>Category</legend> @Html.EditorFor(model => model) <p> <input type="submit" value="Create" /> </p> </fieldset> } <div> @Html.ActionLink("Back to List", "Index") </div> ViewStart file In Razor views, we can add a file named _viewstart.cshtml in the views directory and this will be shared among the all views with in the Views directory. The below code in the _viewstart.cshtml, sets the Layout page for every Views in the Views folder. @{ Layout = "~/Views/Shared/_Layout.cshtml"; } Source Code You can download the source code from http://efmvc.codeplex.com/ . The source will be refactored on over time. Summary In this post, we have created a simple web application using ASP.NET MVC 3 and EF Code First. We have discussed on technologies and practices such as ASP.NET MVC 3, Razor, EF Code First, Unity 2, generic Repository and Unit of Work. In my later posts, I will modify the application and will be discussed on more things. Stay tuned to my blog for more posts on step by step application building.

Read the article

using Generics in C# [closed]

- by Uphaar Goyal

I have started looking into using generics in C#. As an example what i have done is that I have an abstract class which implements generic methods. these generic methods take a sql query, a connection string and the Type T as parameters and then construct the data set, populate the object and return it back. This way each business object does not need to have a method to populate it with data or construct its data set. All we need to do is pass the type, the sql query and the connection string and these methods do the rest.I am providing the code sample here. I am just looking to discuss with people who might have a better solution to what i have done. using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Data; using System.Data.SqlClient; using MWTWorkUnitMgmtLib.Business; using System.Collections.ObjectModel; using System.Reflection; namespace MWTWorkUnitMgmtLib.TableGateway { public abstract class TableGateway { public TableGateway() { } protected abstract string GetConnection(); protected abstract string GetTableName(); public DataSet GetDataSetFromSql(string connectionString, string sql) { DataSet ds = null; using (SqlConnection connection = new SqlConnection(connectionString)) using (SqlCommand command = connection.CreateCommand()) { command.CommandText = sql; connection.Open(); using (ds = new DataSet()) using (SqlDataAdapter adapter = new SqlDataAdapter(command)) { adapter.Fill(ds); } } return ds; } public static bool ContainsColumnName(DataRow dr, string columnName) { return dr.Table.Columns.Contains(columnName); } public DataTable GetDataTable(string connString, string sql) { DataSet ds = GetDataSetFromSql(connString, sql); DataTable dt = null; if (ds != null) { if (ds.Tables.Count 0) { dt = ds.Tables[0]; } } return dt; } public T Construct(DataRow dr, T t) where T : class, new() { Type t1 = t.GetType(); PropertyInfo[] properties = t1.GetProperties(); foreach (PropertyInfo property in properties) { if (ContainsColumnName(dr, property.Name) && (dr[property.Name] != null)) property.SetValue(t, dr[property.Name], null); } return t; } public T GetByID(string connString, string sql, T t) where T : class, new() { DataTable dt = GetDataTable(connString, sql); DataRow dr = dt.Rows[0]; return Construct(dr, t); } public List GetAll(string connString, string sql, T t) where T : class, new() { List collection = new List(); DataTable dt = GetDataTable(connString, sql); foreach (DataRow dr in dt.Rows) collection.Add(Construct(dr, t)); return collection; } } }

Read the article

Sixeyed.Caching available now on NuGet and GitHub!

- by Elton Stoneman

Originally posted on: http://geekswithblogs.net/EltonStoneman/archive/2013/10/22/sixeyed.caching-available-now-on-nuget-and-github.aspxThe good guys at Pluralsight have okayed me to publish my caching framework (as seen in Caching in the .NET Stack: Inside-Out) as an open-source library, and it’s out now. You can get it here: Sixeyed.Caching source code on GitHub, and here: Sixeyed.Caching package v1.0.0 on NuGet. If you haven’t seen the course, there’s a preview here on YouTube: In-Process and Out-of-Process Caches, which gives a good flavour. The library is a wrapper around various cache providers, including the .NET MemoryCache, AppFabric cache, and memcached*. All the wrappers inherit from a base class which gives you a set of common functionality against all the cache implementations: • inherits OutputCacheProvider, so you can use your chosen cache provider as an ASP.NET output cache; • serialization and encryption, so you can configure whether you want your cache items serialized (XML, JSON or binary) and encrypted; • instrumentation, you can optionally use performance counters to monitor cache attempts and hits, at a low level. The framework wraps up different caches into an ICache interface, and it lets you use a provider directly like this: Cache.Memory.Get<RefData>(refDataKey); - or with configuration to use the default cache provider: Cache.Default.Get<RefData>(refDataKey); The library uses Unity’s interception framework to implement AOP caching, which you can use by flagging methods with the [Cache] attribute: [Cache] public RefData GetItem(string refDataKey) - and you can be more specific on the required cache behaviour: [Cache(CacheType=CacheType.Memory, Days=1] public RefData GetItem(string refDataKey) - or really specific: [Cache(CacheType=CacheType.Disk, SerializationFormat=SerializationFormat.Json, Hours=2, Minutes=59)] public RefData GetItem(string refDataKey) Provided you get instances of classes with cacheable methods from the container, the attributed method results will be cached, and repeated calls will be fetched from the cache. You can also set a bunch of cache defaults in application config, like whether to use encryption and instrumentation, and whether the cache system is enabled at all: <sixeyed.caching enabled="true"> <performanceCounters instrumentCacheTotalCounts="true" instrumentCacheTargetCounts="true" categoryNamePrefix ="Sixeyed.Caching.Tests"/> <encryption enabled="true" key="1234567890abcdef1234567890abcdef" iv="1234567890abcdef"/>  </sixeyed.caching> For AOP and methods flagged with the cache attribute, you can override the compile-time cache settings at runtime with more config (keyed by the class and method name): <sixeyed.caching enabled="true"> <targets> <target keyPrefix="MethodLevelCachingStub.GetRandomIntCacheConfiguredInternal" enabled="false"/> <target keyPrefix="MethodLevelCachingStub.GetRandomIntCacheExpiresConfiguredInternal" seconds="1"/> </targets> It’s released under the MIT license, so you can use it freely in your own apps and modify as required. I’ll be adding more content to the GitHub wiki, which will be the main source of documentation, but for now there’s an FAQ to get you started. * - in the course the framework library also wraps NCache Express, but there's no public redistributable library that I can find, so it's not in Sixeyed.Caching.

Read the article

Is it bad to have an "Obsessive Refactoring Disorder"?

- by Rachel

I was reading this question and realized that could almost be me. I am fairly OCD about refactoring someone else's code when I see that I can improve it. For example, if the code contains duplicate methods to do the same thing with nothing more than a single parameter changing, I feel I have to remove all the copy/paste methods and replace it with one generic one. Is this bad? Should I try and stop? I try not to refactor unless I can actually make improvements to the code performance or readability, or if the person who did the code isn't following our standard naming conventions (I hate expecting a variable to be local because of the naming standard, only to discover it is a global variable which has been incorrectly named)

Read the article

Metro: Query Selectors

- by Stephen.Walther

The goal of this blog entry is to explain how to perform queries using selectors when using the WinJS library. In particular, you learn how to use the WinJS.Utilities.query() method and the QueryCollection class to retrieve and modify the elements of an HTML document. Introduction to Selectors When you are building a Web application, you need some way of easily retrieving elements from an HTML document. For example, you might want to retrieve all of the input elements which have a certain class. Or, you might want to retrieve the one and only element with an id of favoriteColor. The standard way of retrieving elements from an HTML document is by using a selector. Anyone who has ever created a Cascading Style Sheet has already used selectors. You use selectors in Cascading Style Sheets to apply formatting rules to elements in a document. For example, the following Cascading Style Sheet rule changes the background color of every INPUT element with a class of .required in a document to the color red: input.red { background-color: red } The “input.red” part is the selector which matches all INPUT elements with a class of red. The W3C standard for selectors (technically, their recommendation) is entitled “Selectors Level 3” and the standard is located here: http://www.w3.org/TR/css3-selectors/ Selectors are not only useful for adding formatting to the elements of a document. Selectors are also useful when you need to apply behavior to the elements of a document. For example, you might want to select a particular BUTTON element with a selector and add a click handler to the element so that something happens whenever you click the button. Selectors are not specific to Cascading Style Sheets. You can use selectors in your JavaScript code to retrieve elements from an HTML document. jQuery is famous for its support for selectors. Using jQuery, you can use a selector to retrieve matching elements from a document and modify the elements. The WinJS library enables you to perform the same types of queries as jQuery using the W3C selector syntax. Performing Queries with the WinJS.Utilities.query() Method When using the WinJS library, you perform a query using a selector by using the WinJS.Utilities.query() method. The following HTML document contains a BUTTON and a DIV element: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Application1</title>  <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script>  <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> </head> <body> <button>Click Me!</button> <div style="display:none"> <h1>Secret Message</h1> </div> </body> </html> The document contains a reference to the following JavaScript file named \js\default.js: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.Utilities.query("button").listen("click", function () { WinJS.Utilities.query("div").clearStyle("display"); }); } }; app.start(); })(); The default.js script uses the WinJS.Utilities.query() method to retrieve all of the BUTTON elements in the page. The listen() method is used to wire an event handler to the BUTTON click event. When you click the BUTTON, the secret message contained in the hidden DIV element is displayed. The clearStyle() method is used to remove the display:none style attribute from the DIV element. Under the covers, the WinJS.Utilities.query() method uses the standard querySelectorAll() method. This means that you can use any selector which is compatible with the querySelectorAll() method when using the WinJS.Utilities.query() method. The querySelectorAll() method is defined in the W3C Selectors API Level 1 standard located here: http://www.w3.org/TR/selectors-api/ Unlike the querySelectorAll() method, the WinJS.Utilities.query() method returns a QueryCollection. We talk about the methods of the QueryCollection class below. Retrieving a Single Element with the WinJS.Utilities.id() Method If you want to retrieve a single element from a document, instead of matching a set of elements, then you can use the WinJS.Utilities.id() method. For example, the following line of code changes the background color of an element to the color red: WinJS.Utilities.id("message").setStyle("background-color", "red"); The statement above matches the one and only element with an Id of message. For example, the statement matches the following DIV element: <div id="message">Hello!</div> Notice that you do not use a hash when matching a single element with the WinJS.Utilities.id() method. You would need to use a hash when using the WinJS.Utilities.query() method to do the same thing like this: WinJS.Utilities.query("#message").setStyle("background-color", "red"); Under the covers, the WinJS.Utilities.id() method calls the standard document.getElementById() method. The WinJS.Utilities.id() method returns the result as a QueryCollection. If no element matches the identifier passed to WinJS.Utilities.id() then you do not get an error. Instead, you get a QueryCollection with no elements (length=0). Using the WinJS.Utilities.children() method The WinJS.Utilities.children() method enables you to retrieve a QueryCollection which contains all of the children of a DOM element. For example, imagine that you have a DIV element which contains children DIV elements like this: <div id="discussContainer"> <div>Message 1</div> <div>Message 2</div> <div>Message 3</div> </div> You can use the following code to add borders around all of the child DIV element and not the container DIV element: var discussContainer = WinJS.Utilities.id("discussContainer").get(0); WinJS.Utilities.children(discussContainer).setStyle("border", "2px dashed red"); It is important to understand that the WinJS.Utilities.children() method only works with a DOM element and not a QueryCollection. Notice that the get() method is used to retrieve the DOM element which represents the discussContainer. Working with the QueryCollection Class Both the WinJS.Utilities.query() method and the WinJS.Utilities.id() method return an instance of the QueryCollection class. The QueryCollection class derives from the base JavaScript Array class and adds several useful methods for working with HTML elements: addClass(name) – Adds a class to every element in the QueryCollection. clearStyle(name) – Removes a style from every element in the QueryCollection. conrols(ctor, options) – Enables you to create controls. get(index) – Retrieves the element from the QueryCollection at the specified index. getAttribute(name) – Retrieves the value of an attribute for the first element in the QueryCollection. hasClass(name) – Returns true if the first element in the QueryCollection has a certain class. include(items) – Includes a collection of items in the QueryCollection. listen(eventType, listener, capture) – Adds an event listener to every element in the QueryCollection. query(query) – Performs an additional query on the QueryCollection and returns a new QueryCollection. removeClass(name) – Removes a class from the every element in the QueryCollection. removeEventListener(eventType, listener, capture) – Removes an event listener from every element in the QueryCollection. setAttribute(name, value) – Adds an attribute to every element in the QueryCollection. setStyle(name, value) – Adds a style attribute to every element in the QueryCollection. template(templateElement, data, renderDonePromiseContract) – Renders a template using the supplied data. toggleClass(name) – Toggles the specified class for every element in the QueryCollection. Because the QueryCollection class derives from the base Array class, it also contains all of the standard Array methods like forEach() and slice(). Summary In this blog post, I’ve described how you can perform queries using selectors within a Windows Metro Style application written with JavaScript. You learned how to return an instance of the QueryCollection class by using the WinJS.Utilities.query(), WinJS.Utilities.id(), and WinJS.Utilities.children() methods. You also learned about the methods of the QueryCollection class.

Read the article

Unlock the Full Value of Oracle CRM On Demand

- by charles.knapp

Register for this live Oracle CRM On Demand Virtual Community Session! Oracle CRM On Demand delivers the most complete On Demand CRM available anywhere. But how can you ensure you are getting maximum value from the many powerful features that Oracle CRM On Demand offers? Join our interactive Oracle CRM On Demand Virtual Community Session on Tuesday, January 11, 2011 from 10.00-11 a.m. PT / 1 p.m.-2 p.m. ET to get expert advice and discuss the best ways to unlock the full potential of Oracle CRM Demand with Mike Lairson, author of 'Oracle CRM On Demand Reporting'. Book OfferSend your Oracle CRM On Demand configuration ideas before the Webcast to [email protected] and you could win a free copy of 'Oracle CRM On Demand Reporting' by Mike Lairson. Learn more and register now!

Read the article

Entity Framework v1 – tips and Tricks Part 3

- by Rohit Gupta

General Tips on Entity Framework v1 & Linq to Entities: ToTraceString() If you need to know the underlying SQL that the EF generates for a Linq To Entities query, then use the ToTraceString() method of the ObjectQuery class. (or use LINQPAD) Note that you need to cast the LINQToEntities query to ObjectQuery before calling TotraceString() as follows: 1: string efSQL = ((ObjectQuery)from c in ctx.Contact 2: where c.Address.Any(a => a.CountryRegion == "US") 3: select c.ContactID).ToTraceString(); ================================================================================ MARS or MultipleActiveResultSet When you create a EDM Model (EDMX file) from the database using Visual Studio, it generates a connection string with the same name as the name of the EntityContainer in CSDL. In the ConnectionString so generated it sets the MultipleActiveResultSet attribute to true by default. So if you are running the following query then it streams multiple readers over the same connection: 1: using (BAEntities context = new BAEntities()) 2: { 3: var cons = 4: from con in context.Contacts 5: where con.FirstName == "Jose" 6: select con; 7: foreach (var c in cons) 8: { 9: if (c.AddDate < new System.DateTime(2007, 1, 1)) 10: { 11: c.Addresses.Load(); 12: } 13: } 14: } ================================================================================= Explicitly opening and closing EntityConnection When you call ToList() or foreach on a LINQToEntities query the EF automatically closes the connection after all the records from the query have been consumed. Thus if you need to run many LINQToEntities queries over the same connection then explicitly open and close the connection as follows: 1: using (BAEntities context = new BAEntities()) 2: { 3: context.Connection.Open(); 4: var cons = from con in context.Contacts where con.FirstName == "Jose" 5: select con; 6: var conList = cons.ToList(); 7: var allCustomers = from con in context.Contacts.OfType<Customer>() 8: select con; 9: var allcustList = allCustomers.ToList(); 10: context.Connection.Close(); 11: } ====================================================================== Dispose ObjectContext only if required After you retrieve entities using the ObjectContext and you are not explicitly disposing the ObjectContext then insure that your code does consume all the records from the LinqToEntities query by calling .ToList() or foreach statement, otherwise the the database connection will remain open and will be closed by the garbage collector when it gets to dispose the ObjectContext. Secondly if you are making updates to the entities retrieved using LinqToEntities then insure that you dont inadverdently dispose of the ObjectContext after the entities are retrieved and before calling .SaveChanges() since you need the SAME ObjectContext to keep track of changes made to the Entities (by using ObjectStateEntry objects). So if you do need to explicitly dispose of the ObjectContext do so only after calling SaveChanges() and only if you dont need to change track the entities retrieved any further. ======================================================================= SQL InjectionAttacks under control with EFv1 LinqToEntities and LinqToSQL queries are parameterized before they are sent to the DB hence they are not vulnerable to SQL Injection attacks. EntitySQL may be slightly vulnerable to attacks since it does not use parameterized queries. However since the EntitySQL demands that the query be valid Entity SQL syntax and valid native SQL syntax at the same time. So the only way one can do a SQLInjection Attack is by knowing the SSDL of the EDM Model and be able to write the correct EntitySQL (note one cannot append regular SQL since then the query wont be a valid EntitySQL syntax) and append it to a parameter. ====================================================================== Improving Performance You can convert the EntitySets and AssociationSets in a EDM Model into precompiled Views using the edmgen utility. for e.g. the Customer Entity can be converted into a precompiled view using edmgen and all LinqToEntities query against the contaxt.Customer EntitySet will use the precompiled View instead of the EntitySet itself (the same being true for relationships (EntityReference & EntityCollections of a Entity)). The advantage being that when using precompiled views the performance will be much better. The syntax for generating precompiled views for a existing EF project is : edmgen /mode:ViewGeneration /inssdl:BAModel.ssdl /incsdl:BAModel.csdl /inmsl:BAModel.msl /p:Chap14.csproj Note that this will only generate precompiled views for EntitySets and Associations and not for existing LinqToEntities queries in the project.(for that use CompiledQuery.Compile<>) Secondly if you have a LinqToEntities query that you need to run multiple times, then one should precompile the query using CompiledQuery.Compile method. The CompiledQuery.Compile<> method accepts a lamda expression as a parameter, which denotes the LinqToEntities query that you need to precompile. The following is a example of a lamda that we can pass into the CompiledQuery.Compile() method 1: Expression<Func<BAEntities, string, IQueryable<Customer>>> expr = (BAEntities ctx1, string loc) => 2: from c in ctx1.Contacts.OfType<Customer>() 3: where c.Reservations.Any(r => r.Trip.Destination.DestinationName == loc) 4: select c; Then we call the Compile Query as follows: 1: var query = CompiledQuery.Compile<BAEntities, string, IQueryable<Customer>>(expr); 2: 3: using (BAEntities ctx = new BAEntities()) 4: { 5: var loc = "Malta"; 6: IQueryable<Customer> custs = query.Invoke(ctx, loc); 7: var custlist = custs.ToList(); 8: foreach (var item in custlist) 9: { 10: Console.WriteLine(item.FullName); 11: } 12: } Note that if you created a ObjectQuery or a Enitity SQL query instead of the LINQToEntities query, you dont need precompilation for e.g. 1: An Example of EntitySQL query : 2: string esql = "SELECT VALUE c from Contacts AS c where c is of(BAGA.Customer) and c.LastName = 'Gupta'"; 3: ObjectQuery<Customer> custs = CreateQuery<Customer>(esql); 1: An Example of ObjectQuery built using ObjectBuilder methods: 2: from c in Contacts.OfType<Customer>().Where("it.LastName == 'Gupta'") 3: select c This is since the Query plan is cached and thus the performance improves a bit, however since the ObjectQuery or EntitySQL query still needs to materialize the results into Entities hence it will take the same amount of performance hit as with LinqToEntities. However note that not ALL EntitySQL based or QueryBuilder based ObjectQuery plans are cached. So if you are in doubt always create a LinqToEntities compiled query and use that instead ============================================================ GetObjectStateEntry Versus GetObjectByKey We can get to the Entity being referenced by the ObjectStateEntry via its Entity property and there are helper methods in the ObjectStateManager (osm.TryGetObjectStateEntry) to get the ObjectStateEntry for a entity (for which we know the EntityKey). Similarly The ObjectContext has helper methods to get an Entity i.e. TryGetObjectByKey(). TryGetObjectByKey() uses GetObjectStateEntry method under the covers to find the object, however One important difference between these 2 methods is that TryGetObjectByKey queries the database if it is unable to find the object in the context, whereas TryGetObjectStateEntry only looks in the context for existing entries. It will not make a trip to the database ============================================================= POCO objects with EFv1: To create POCO objects that can be used with EFv1. We need to implement 3 key interfaces: IEntityWithKey IEntityWithRelationships IEntityWithChangeTracker Implementing IEntityWithKey is not mandatory, but if you dont then we need to explicitly provide values for the EntityKey for various functions (for e.g. the functions needed to implement IEntityWithChangeTracker and IEntityWithRelationships). Implementation of IEntityWithKey involves exposing a property named EntityKey which returns a EntityKey object. Implementation of IEntityWithChangeTracker involves implementing a method named SetChangeTracker since there can be multiple changetrackers (Object Contexts) existing in memory at the same time. 1: public void SetChangeTracker(IEntityChangeTracker changeTracker) 2: { 3: _changeTracker = changeTracker; 4: } Additionally each property in the POCO object needs to notify the changetracker (objContext) that it is updating itself by calling the EntityMemberChanged and EntityMemberChanging methods on the changeTracker. for e.g.: 1: public EntityKey EntityKey 2: { 3: get { return _entityKey; } 4: set 5: { 6: if (_changeTracker != null) 7: { 8: _changeTracker.EntityMemberChanging("EntityKey"); 9: _entityKey = value; 10: _changeTracker.EntityMemberChanged("EntityKey"); 11: } 12: else 13: _entityKey = value; 14: } 15: } 16: ===================== Custom Property ==================================== 17: 18: [EdmScalarPropertyAttribute(IsNullable = false)] 19: public System.DateTime OrderDate 20: { 21: get { return _orderDate; } 22: set 23: { 24: if (_changeTracker != null) 25: { 26: _changeTracker.EntityMemberChanging("OrderDate"); 27: _orderDate = value; 28: _changeTracker.EntityMemberChanged("OrderDate"); 29: } 30: else 31: _orderDate = value; 32: } 33: } Finally you also need to create the EntityState property as follows: 1: public EntityState EntityState 2: { 3: get { return _changeTracker.EntityState; } 4: } The IEntityWithRelationships involves creating a property that returns RelationshipManager object: 1: public RelationshipManager RelationshipManager 2: { 3: get 4: { 5: if (_relManager == null) 6: _relManager = RelationshipManager.Create(this); 7: return _relManager; 8: } 9: } ============================================================ Tip : ProviderManifestToken – change EDMX File to use SQL 2008 instead of SQL 2005 To use with SQL Server 2008, edit the EDMX file (the raw XML) changing the ProviderManifestToken in the SSDL attributes from "2005" to "2008" ============================================================= With EFv1 we cannot use Structs to replace a anonymous Type while doing projections in a LINQ to Entities query. While the same is supported with LINQToSQL, it is not with LinqToEntities. For e.g. the following is not supported with LinqToEntities since only parameterless constructors and initializers are supported in LINQ to Entities. (the same works with LINQToSQL) 1: public struct CompanyInfo 2: { 3: public int ID { get; set; } 4: public string Name { get; set; } 5: } 6: var companies = (from c in dc.Companies 7: where c.CompanyIcon == null 8: select new CompanyInfo { Name = c.CompanyName, ID = c.CompanyId }).ToList(); ;

Read the article

Gnome Shell segfault in libglib-2.0

- by slohui

I have been using Ubuntu 11.10 + Gnome Shell with a Nvidia card, but now I've moved it to my new PC which has an ATI card, at first it wasn't booting but I installed the driver from amd.com and then it worked. Anyway my problem is that gnome-shell is crashing, mostly when I try to start a VirtualBox machine (it happened in other times but I don't remember what I was doing). Sometimes gnome-shell respawns and it continue working but sometimes it doesn't so I have to restart lightdm and lose all the windows I was using. Here's some of the syslog when the crash occurs: Apr 9 12:20:08 desktop-1 NetworkManager[1032]: SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/vboxnet0, iface: vboxnet0) Apr 9 12:20:08 desktop-1 NetworkManager[1032]: SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/vboxnet0, iface: vboxnet0): no ifupdown configuration found. Apr 9 12:20:08 desktop-1 NetworkManager[1032]: <warn> /sys/devices/virtual/net/vboxnet0: couldn't determine device driver; ignoring... Apr 9 12:20:08 desktop-1 kernel: [ 4498.689561] warning: `VirtualBox' uses 32-bit capabilities (legacy support in use) Apr 9 12:24:29 desktop-1 gnome-session[1617]: WARNING: Application 'gnome-shell.desktop' killed by signal Apr 9 12:24:45 desktop-1 gnome-session[1617]: WARNING: App 'gnome-shell.desktop' respawning too quickly Apr 9 12:24:45 desktop-1 gnome-session[1617]: CRITICAL: We failed, but the fail whale is dead. Sorry.... Apr 9 12:25:20 desktop-1 kernel: [ 4810.769775] show_signal_msg: 30 callbacks suppressed |----- > Apr 9 12:25:20 desktop-1 kernel: [ 4810.769785] gnome-shell[3427]: segfault at b0 ip b6bd09cd sp bfc9b650 error 4 in libglib-2.0.so.0.3000.0[b6b71000+f7000]** Apr 9 12:25:20 desktop-1 gnome-session[1617]: WARNING: Application 'gnome-shell.desktop' killed by signal Apr 9 12:25:23 desktop-1 kernel: [ 4814.055705] EXT4-fs (sda1): Unaligned AIO/DIO on inode 133295 by VirtualBox; performance will be poor. Apr 9 12:26:55 desktop-1 gnome-session[1617]: Gdk-WARNING: gnome-session: Fatal IO error 11 (Resource temporarily unavailable) on X server :0.#012 Apr 9 12:26:55 desktop-1 kernel: [ 4905.373256] [fglrx] IRQ 56 Disabled Apr 9 12:26:59 desktop-1 acpid: client 1124[0:0] has disconnected Apr 9 12:26:59 desktop-1 acpid: client connected from 3864[0:0] Apr 9 12:26:59 desktop-1 acpid: 1 client rule loaded Apr 9 12:26:59 desktop-1 kernel: [ 4909.700095] fglrx_pci 0000:02:00.0: irq 56 for MSI/MSI-X Apr 9 12:26:59 desktop-1 kernel: [ 4909.701466] [fglrx] Firegl kernel thread PID: 3867 Apr 9 12:26:59 desktop-1 kernel: [ 4909.701625] [fglrx] Firegl kernel thread PID: 3868 Apr 9 12:26:59 desktop-1 kernel: [ 4909.701852] [fglrx] Firegl kernel thread PID: 3869 Apr 9 12:26:59 desktop-1 kernel: [ 4909.702021] [fglrx] IRQ 56 Enabled Apr 9 12:26:59 desktop-1 kernel: [ 4909.861815] [fglrx] Gart USWC size:1280 M. Apr 9 12:26:59 desktop-1 kernel: [ 4909.861817] [fglrx] Gart cacheable size:508 M. Apr 9 12:26:59 desktop-1 kernel: [ 4909.861820] [fglrx] Reserved FB block: Shared offset:0, size:1000000 Apr 9 12:26:59 desktop-1 kernel: [ 4909.861821] [fglrx] Reserved FB block: Unshared offset:f8fd000, size:403000 Apr 9 12:26:59 desktop-1 kernel: [ 4909.861823] [fglrx] Reserved FB block: Unshared offset:3fff4000, size:c000 Does anyone could guide me on how to fix this? Or the proper place where to ask for help.

Read the article

ASP.NET MVC 3 Hosting :: ASP.NET MVC 3 First Look

- by mbridge

MVC 3 View Enhancements MVC 3 introduces two improvements to the MVC view engine: - Ability to select the view engine to use. MVC 3 allows you to select from any of your installed view engines from Visual Studio by selecting Add > View (including the newly introduced ASP.NET “Razor” engine”): - Support for the next ASP.NET “Razor” syntax. The newly previewed Razor syntax is a concise lightweight syntax. MVC 3 Control Enhancements - Global Filters: ASP.NET MVC 3 allows you to specify that a filter which applies globally to all Controllers within an app by adding it to the GlobalFilters collection. The RegisterGlobalFilters() method is now included in the default Global.asax class template and so provides a convenient place to do this since is will then be called by the Application_Start() method: void RegisterGlobalFilters(GlobalFilterCollection filters) { filters.Add(new HandleLoggingAttribute()); filters.Add(new HandleErrorAttribute()); } void Application_Start() { RegisterGlobalFilters (GlobalFilters.Filters); } - Dynamic ViewModel Property : MVC 3 augments the ViewData API with a new “ViewModel” property on Controller which is of type “dynamic” – and therefore enables you to use the new dynamic language support in C# and VB pass ViewData items using a cleaner syntax than the current dictionary API. Public ActionResult Index() { ViewModel.Message = "Hello World"; return View(); } - New ActionResult Types : MVC 3 includes three new ActionResult types and helper methods: 1. HttpNotFoundResult – indicates that a resource which was requested by the current URL was not found. HttpNotFoundResult will return a 404 HTTP status code to the calling client. 2. PermanentRedirects – The HttpRedirectResult class contains a new Boolean “Permanent” property which is used to indicate that a permanent redirect should be done. Permanent redirects use a HTTP 301 status code. The Controller class includes three new methods for performing these permanent redirects: RedirectPermanent(), RedirectToRoutePermanent(), andRedirectToActionPermanent(). All of these methods will return an instance of the HttpRedirectResult object with the Permanent property set to true. 3. HttpStatusCodeResult – used for setting an explicit response status code and its associated description. MVC 3 AJAX and JavaScript Enhancements MVC 3 ships with built-in JSON binding support which enables action methods to receive JSON-encoded data and then model-bind it to action method parameters. For example a jQuery client-side JavaScript could define a “save” event handler which will be invoked when the save button is clicked on the client. The code in the event handler then constructs a client-side JavaScript “product” object with 3 fields with their values retrieved from HTML input elements. Finally, it uses jQuery’s .ajax() method to POST a JSON based request which contains the product to a /theStore/UpdateProduct URL on the server: $('#save').click(function () { var product = { ProdName: $('#Name').val() Price: $('#Price').val(), } $.ajax({ url: '/theStore/UpdateProduct', type: "POST"; data: JSON.stringify(widget), datatype: "json", contentType: "application/json; charset=utf-8", success: function () { $('#message').html('Saved').fadeIn(), }, error: function () { $('#message').html('Error').fadeIn(), } }); return false; }); MVC will allow you to implement the /theStore/UpdateProduct URL on the server by using an action method as below. The UpdateProduct() action method will accept a strongly-typed Product object for a parameter. MVC 3 can now automatically bind an incoming JSON post value to the .NET Product type on the server without having to write any custom binding. [HttpPost] public ActionResult UpdateProduct(Product product) { // save logic here return null } MVC 3 Model Validation Enhancements MVC 3 builds on the MVC 2 model validation improvements by adding support for several of the new validation features within the System.ComponentModel.DataAnnotations namespace in .NET 4.0: - Support for the new DataAnnotations metadata attributes like DisplayAttribute. - Support for the improvements made to the ValidationAttribute class which now supports a new IsValid overload that provides more info on the current validation context, like what object is being validated. - Support for the new IValidatableObject interface which enables you to perform model-level validation and also provide validation error messages which are specific to the state of the overall model. MVC 3 Dependency Injection Enhancements MVC 3 includes better support for applying Dependency Injection (DI) and also integrating with Dependency Injection/IOC containers. Currently MVC 3 Preview 1 has support for DI in the below places: - Controllers (registering & injecting controller factories and injecting controllers) - Views (registering & injecting view engines, also for injecting dependencies into view pages) - Action Filters (locating and injecting filters) And this is another important blog about Microsoft .NET and technology: - Windows 2008 Blog - SharePoint 2010 Blog - .NET 4 Blog And you can visit here if you're looking for ASP.NET MVC 3 hosting

Read the article

Unlock the Full Value of Oracle CRM On Demand

- by ruth.donohue

Register for this live Oracle CRM On Demand Virtual Community Session! Oracle CRM On Demand delivers the most complete On Demand CRM solution on the market. But how can you ensure you are getting maximum value from the many powerful features that Oracle CRM On Demand offers? Join our interactive Oracle CRM On Demand Virtual Community Session on Tuesday, January 11, 2011 from 10.00-11 a.m. PT / 1 p.m.-2 p.m. ET to get expert advice and discuss the best ways to unlock the full potential of Oracle CRM Demand with Mike Lairson, author of 'Oracle CRM On Demand Reporting'. Book Offer Send your Oracle CRM On Demand configuration ideas before the Webcast to [email protected] and you could win a free copy of 'Oracle CRM On Demand Reporting' by Mike Lairson. Learn more and register now!

Read the article

How do I disable unwanted iPXE boot attempt in Libvirt/qemu-kvm?

- by gertvdijk

Somehow after upgrading to 12.04, my virtual machines always boot with an attempt to boot from the network first. See this: while I don't have any PXE configuration set: I've tried: to disable SPICE, by changing the emulator to /usr/bin/kvm from /usr/bin/kvm-spice by editing the XML. Ctrl+B to configure the iPXE, but it doesn't let disable this as a boot option. setting another type of NIC - not an option, I need virtio for performance reasons. However, e1000e doesn't work either. removing the NIC: works. However, I need network. Googling around. Hard. Lots of result is about failing configured PXE boots. Not a big issue, but it increases boot times by 50-100% here (booting from SSD), so it's relatively long and annoys me. How can I disable this and boot from virtual hard disk directly?

Read the article

Multicast delegates in c#

- by Jalpesh P. Vadgama

In yesterday’s post We learn about Delegates and how we can use delegates in C#. In today’s blog post we are going to learn about Multicast delegates. What is Multicast Delegates? As we all know we can assign methods as object to delegate and later on we can call that method with the help delegates. We can also assign more then methods to delegates that is called Multicast delegates. It’s provide functionality to execute more then method at a time. It’s maintain delegates as invocation list (linked list). Let’s understands that via a example. We are going to use yesterday’s example and then we will extend that code multicast delegates. Following code I have written to demonstrate the multicast delegates. using System; namespace Delegates { class Program { public delegate void CalculateNumber(int a, int b); static void Main(string[] args) { int a = 5; int b = 5; CalculateNumber addNumber = new CalculateNumber(AddNumber); CalculateNumber multiplyNumber = new CalculateNumber(MultiplyNumber); CalculateNumber multiCast = (CalculateNumber)Delegate.Combine (addNumber, multiplyNumber); multiCast.Invoke(a,b); Console.ReadLine(); } public static void AddNumber(int a, int b) { Console.WriteLine("Adding Number"); Console.WriteLine(5 + 6); } public static void MultiplyNumber(int a, int b) { Console.WriteLine("Multiply Number"); Console.WriteLine(5 + 6); } } } As you can see in the above code I have created two method one for adding two numbers and another for multiply two number. After that I have created two same CalculateNumber delegates addNumber and multiplyNumber then I have create a multicast delegates multiCast with combining two delegates. Now I want to call this both method so I have used Invoke method to call this delegates. As now our code is let’s run the application. Following is a output as expected. As you can we can execute multiple methods with multicast delegates the only thing you need to take care is that we need to type for both delegates. That’s it. Hope you like it. Stay tuned for more.. Till then happy programming.

Read the article

VirtualBox Ubuntu Server with DNS

- by Boris Karl Schlein

I just want to have a local server inside my VirtualBox that offers dns functionality like www.example.local = 127.0.0.1 . Host: Ubuntu 11.10, Guest: Ubuntu 10.10 On my server I can already ping www.example.local - so I configured my virtual host correctly. Question is, how can I address www.example.local from outside my VirtualBox? I searched Google and askubuntu and found dnsmasq. I installed dnsmasq on my server and followed all steps on help.ubuntu. On my host system I've set 192.168.178.91 to the list of dns servers (192.168.178.91 is the IP address of my local server which uses a bridged network adapter). Thing is, I still cannot ping (or connect to) my example.local virtual host. It gives me an unknown host response. How can I set up my DNS server correctly?

Read the article

Sublime text 2 syntax highlighter?

- by BigSack

I have coded my first custom syntax highlighter for sublime text 2, but i don't know how to install it. It is based on notepad++ highlighter found here https://70995658-a-62cb3a1a-s-sites.googlegroups.com/site/lohanplus/files/smali_npp.xml?attachauth=ANoY7criVTO9bDmIGrXwhZLQ_oagJzKKJTlbNDGRzMDVpFkO5i0N6hk_rWptvoQC1tBlNqcqFDD5NutD_2vHZx1J7hcRLyg1jruSjebHIeKdS9x0JCNrsRivgs6DWNhDSXSohkP1ZApXw0iQ0MgqcXjdp7CkJJ6pY_k5Orny9TfK8UWn_HKFsmPcpp967NMPtUnd--ad-BImtkEi-fox2tjs7zc5LabkDQ%3D%3D&attredirects=0&d=1 <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>fileTypes</key> <array> <string>smali</string> </array> <dict> <key>Word1</key> <string>add-double add-double/2addr add-float add-float/2addr add-int add-int/2addr add-int/lit16 add-int/lit8 add-long add-long/2addr aget aget-boolean aget-byte aget-char aget-object aget-short aget-wide and-int and-int/2addr and-int/lit16 and-int/lit8 and-long and-long/2addr aput aput-boolean aput-byte aput-char aput-object aput-short aput-wide array-length check-cast cmp-long cmpg-double cmpg-float cmpl-double cmpl-float const const-class const-string const-string-jumbo const-wide const-wide/16 const-wide/32 const-wide/high16 const/16 const/4 const/high16 div-double div-double/2addr div-float div-float/2addr div-int div-int/2addr div-int/lit16 div-int/lit8 div-long div-long/2addr double-to-float double-to-int double-to-long execute-inline fill-array-data filled-new-array filled-new-array/range float-to-double float-to-int float-to-long goto goto/16 goto/32 if-eq if-eqz if-ge if-gez if-gt if-gtz if-le if-lez if-lt if-ltz if-ne if-nez iget iget-boolean iget-byte iget-char iget-object iget-object-quick iget-quick iget-short iget-wide iget-wide-quick instance-of int-to-byte int-to-char int-to-double int-to-float int-to-long int-to-short invoke-direct invoke-direct-empty invoke-direct/range invoke-interface invoke-interface/range invoke-static invoke-static/range invoke-super invoke-super-quick invoke-super-quick/range invoke-super/range invoke-virtual invoke-virtual-quick invoke-virtual-quick/range invoke-virtual/range iput iput-boolean iput-byte iput-char iput-object iput-object-quick iput-quick iput-short iput-wide iput-wide-quick long-to-double long-to-float long-to-int monitor-enter monitor-exit move move-exception move-object move-object/16 move-object/from16 move-result move-result-object move-result-wide move-wide move-wide/16 move-wide/from16 move/16 move/from16 mul-double mul-double/2addr mul-float mul-float/2addr mul-int mul-int/2addr mul-int/lit8 mul-int/lit16 mul-long mul-long/2addr neg-double neg-float neg-int neg-long new-array new-instance nop not-int not-long or-int or-int/2addr or-int/lit16 or-int/lit8 or-long or-long/2addr rem-double rem-double/2addr rem-float rem-float/2addr rem-int rem-int/2addr rem-int/lit16 rem-int/lit8 rem-long rem-long/2addr return return-object return-void return-wide rsub-int rsub-int/lit8 sget sget-boolean sget-byte sget-char sget-object sget-short sget-wide shl-int shl-int/2addr shl-int/lit8 shl-long shl-long/2addr shr-int shr-int/2addr shr-int/lit8 shr-long shr-long/2addr sparse-switch sput sput-boolean sput-byte sput-char sput-object sput-short sput-wide sub-double sub-double/2addr sub-float sub-float/2addr sub-int sub-int/2addr sub-int/lit16 sub-int/lit8 sub-long sub-long/2addr throw throw-verification-error ushr-int ushr-int/2addr ushr-int/lit8 ushr-long ushr-long/2addr xor-int xor-int/2addr xor-int/lit16 xor-int/lit8 xor-long xor-long/2addr</string> </dict> <dict> <key>Word2</key> <string>v0 v1 v2 v3 v4 v5 v6 v7 v8 v9 v10 v11 v12 v13 v14 v15 v16 v17 v18 v19 v20 v21 v22 v23 v24 v25 v26 v27 v28 v29 v30 v31 v32 v33 v34 v35 v36 v37 v38 v39 v40 v41 v42 v43 v44 v45 v46 v47 v48 v49 v50 p0 p1 p2 p3 p4 p5 p6 p7 p8 p9 p10 p11 p12 p13 p14 p15 p16 p17 p18 p19 p20 p21 p22 p23 p24 p25 p26 p27 p28 p29 p30</string> </dict> <dict> <key>Word3</key> <string>array-data .catch .catchall .class .end .end\ local .enum .epilogue .field .implements .line .local .locals .parameter .prologue .registers .restart .restart\ local .source .subannotation .super</string> </dict> <dict> <key>Word4</key> <string>abstract bridge constructor declared-synchronized enum final interface native private protected public static strictfp synchronized synthetic system transient varargs volatile</string> </dict> <dict> <key>Word4</key> <string>("0)"0</string> </dict> <dict> <key>Word5</key> <string>.method .annotation .sparse-switch .packed-switch</string> </dict> <dict> <key>word6</key> <string>.end\ method .end\ annotation .end\ sparse-switch .end\ packed-switch</string> </dict> <dict> <key>word7</key> <string>" ( ) , ; { } ></string> </dict> <key>uuid</key> <string>27798CC6-6B1D-11D9-B8FA-000D93589AF6</string> </dict> </plist>

Read the article

how to access inaccessible mac os x hard drive via ubuntu

- by jon

Background: My intention was to load a Virtual Machine (VM) on my Mac OS X Snow Leopard. My Mac had just enough room for a VM (my thought process was that VM was the same as partition) However, I burned the newest version of Ubuntu onto a CD, thinking that partitioning and running a virtual machine would be the same. I would restart my computer, booting up Ubuntu installer. The installation would not allow me to partition, forcing me to force shutdown my laptop. when I turn on my laptop, I see that my computer is "missing operating system". So, can someone help me fix my a) bootcamp, b) getting files and if a and b are fixed c) to install ubuntu as a VM?

Read the article

IBM Offers Mainframe Data Deduplication

Big Blue unveils a virtual tape library with deduplication capabilities for backing up z/OS environments.

Read the article

Getting Started With nServiceBus on VAN Mar 31

- by van

Topic: nServiceBus is mature and powerful open source framework that enables to design robust, scalable, message-based, service-oriented architectures. Latest improvements in the configuration API enables developers to quickly get started and build a working simple system that uses messaging infrastructure. The goal of this session is to give a jump start with the framework, introduce basic concepts such as message handlers, Sagas, Pub/Sub, Generic Host and also create a working demo application that uses publish/subscribe messaging. The content of the session is addressed to developers that are interested in learning how to get started using nServiceBus in order to design and build distributed systems. Bio: Bernard Kowalski is currently a Software Developer at Microdesk, one of Autodesk's leading partners in providing variety of Geospatial and Computer-Aided Design solutions. Bernard has experience developing .NET framework-based applications utilizing Windows Forms, Windows Services, ASP.NET MVC, and Web services. In a recent project, Bernard architected and implemented a distributed system based on SOA principles using an open source implementation of an Enterprise Service Bus. Bernard develops software with Agile patterns and practices using Domain Driven Design combined with TDD (Test Driven Development). He is familiar with all of the following APIs: Autodesk Vault/Product Stream API, AutoCAD ActiveX/VBA/.NET API, AutoCAD Mechanical API, Autodesk Inventor API, Autodesk MapGuide Enterprise. Prior to joining Microdesk, Bernard worked as a researcher and teacher at the University of Science and Technology in Krakow, Poland where he was awarded with a PhD in Computer Methods in Materials Science. He also participated in research projects where he developed applications for analysis of hot compression test results using advanced optimization techniques. He also developed Finite Element Method-based programs for thermal and stress analysis using C++ and FORTRAN. Bernard is a member of the Domain Driven Design and ALT.NET user groups in NYC. Virtual ALT.NET (VAN) is the online gathering place of the ALT.NET community. Through conversations, presentations, pair programming and dojos, we strive to improve, explore, and challenge the way we create software. Using net conferencing technology such as Skype and LiveMeeting, we hold regular meetings, open to anyone, usually taking the form of a presentation or an Open Space Technology-style conversation. Please see the Calendar(http://www.virtualaltnet.com/Home/Calendar) to find a VAN group that meets at a time convenient to you, and feel welcome to join a meeting. Past sessions can be found on the Recording page. To stay informed about VAN activities, you can subscribe to the Virtual ALT.NET Google Group and follow the Virtual ALT.NET blog. Times below are Central Standard Time Start Time: Wed, Mar 31, 2010 8:00 PM UTC/GMT -5 hours End Time: Wed, Mar 31, 2010 10:00 PM UTC/GMT -5 hours Attendee URL: http://www.virtualaltnet.com/van Zach Young http://www.virtualaltnet.com

Read the article

O’Reilly E-Book of the Day 15/Aug/2014 - Advanced Quantitative Finance with C++

- by TATWORTH

Originally posted on: http://geekswithblogs.net/TATWORTH/archive/2014/08/15/orsquoreilly-e-book-of-the-day-15aug2014---advanced-quantitative-finance.aspxToday’s half-price book of the Day offer from O’Reilly at http://shop.oreilly.com/product/9781782167228.do?code=MSDEAL is Advanced Quantitative Finance with C++. “This book will introduce you to the key mathematical models used to price financial derivatives, as well as the implementation of main numerical models used to solve them. In particular, equity, currency, interest rates, and credit derivatives are discussed. In the first part of the book, the main mathematical models used in the world of financial derivatives are discussed. Next, the numerical methods used to solve the mathematical models are presented. Finally, both the mathematical models and the numerical methods are used to solve some concrete problems in equity, forex, interest rate, and credit derivatives.”

Read the article

ASP.NET Web API and Simple Value Parameters from POSTed data

- by Rick Strahl

In testing out various features of Web API I've found a few oddities in the way that the serialization is handled. These are probably not super common but they may throw you for a loop. Here's what I found. Simple Parameters from Xml or JSON Content Web API makes it very easy to create action methods that accept parameters that are automatically parsed from XML or JSON request bodies. For example, you can send a JavaScript JSON object to the server and Web API happily deserializes it for you. This works just fine:public string ReturnAlbumInfo(Album album) { return album.AlbumName + " (" + album.YearReleased.ToString() + ")"; } However, if you have methods that accept simple parameter types like strings, dates, number etc., those methods don't receive their parameters from XML or JSON body by default and you may end up with failures. Take the following two very simple methods:public string ReturnString(string message) { return message; } public HttpResponseMessage ReturnDateTime(DateTime time) { return Request.CreateResponse<DateTime>(HttpStatusCode.OK, time); } The first one accepts a string and if called with a JSON string from the client like this:var client = new HttpClient(); var result = client.PostAsJsonAsync<string>(http://rasxps/AspNetWebApi/albums/rpc/ReturnString, "Hello World").Result; which results in a trace like this: POST http://rasxps/AspNetWebApi/albums/rpc/ReturnString HTTP/1.1Content-Type: application/json; charset=utf-8Host: rasxpsContent-Length: 13Expect: 100-continueConnection: Keep-Alive "Hello World" produces… wait for it: null. Sending a date in the same fashion:var client = new HttpClient(); var result = client.PostAsJsonAsync<DateTime>(http://rasxps/AspNetWebApi/albums/rpc/ReturnDateTime, new DateTime(2012, 1, 1)).Result; results in this trace: POST http://rasxps/AspNetWebApi/albums/rpc/ReturnDateTime HTTP/1.1Content-Type: application/json; charset=utf-8Host: rasxpsContent-Length: 30Expect: 100-continueConnection: Keep-Alive "\/Date(1325412000000-1000)\/" (yes still the ugly MS AJAX date, yuk! This will supposedly change by RTM with Json.net used for client serialization) produces an error response: The parameters dictionary contains a null entry for parameter 'time' of non-nullable type 'System.DateTime' for method 'System.Net.Http.HttpResponseMessage ReturnDateTime(System.DateTime)' in 'AspNetWebApi.Controllers.AlbumApiController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter. Basically any simple parameters are not parsed properly resulting in null being sent to the method. For the string the call doesn't fail, but for the non-nullable date it produces an error because the method can't handle a null value. This behavior is a bit unexpected to say the least, but there's a simple solution to make this work using an explicit [FromBody] attribute:public string ReturnString([FromBody] string message) andpublic HttpResponseMessage ReturnDateTime([FromBody] DateTime time) which explicitly instructs Web API to read the value from the body. UrlEncoded Form Variable Parsing Another similar issue I ran into is with POST Form Variable binding. Web API can retrieve parameters from the QueryString and Route Values but it doesn't explicitly map parameters from POST values either. Taking our same ReturnString function from earlier and posting a message POST variable like this:var formVars = new Dictionary<string,string>(); formVars.Add("message", "Some Value"); var content = new FormUrlEncodedContent(formVars); var client = new HttpClient(); var result = client.PostAsync(http://rasxps/AspNetWebApi/albums/rpc/ReturnString, content).Result; which produces this trace: POST http://rasxps/AspNetWebApi/albums/rpc/ReturnString HTTP/1.1Content-Type: application/x-www-form-urlencodedHost: rasxpsContent-Length: 18Expect: 100-continue message=Some+Value When calling ReturnString:public string ReturnString(string message) { return message; } unfortunately it does not map the message value to the message parameter. This sort of mapping unfortunately is not available in Web API. Web API does support binding to form variables but only as part of model binding, which binds object properties to the POST variables. Sending the same message as in the previous example you can use the following code to pick up POST variable data:public string ReturnMessageModel(MessageModel model) { return model.Message; } public class MessageModel { public string Message { get; set; }} Note that the model is bound and the message form variable is mapped to the Message property as would other variables to properties if there were more. This works but it's not very dynamic. There's no real easy way to retrieve form variables (or query string values for that matter) in Web API's Request object as far as I can discern. Well only if you consider this easy:public string ReturnString() { var formData = Request.Content.ReadAsAsync<FormDataCollection>().Result; return formData.Get("message"); } Oddly FormDataCollection does not allow for indexers to work so you have to use the .Get() method which is rather odd. If you're running under IIS/Cassini you can always resort to the old and trusty HttpContext access for request data:public string ReturnString() { return HttpContext.Current.Request.Form["message"]; } which works fine and is easier. It's kind of a bummer that HttpRequestMessage doesn't expose some sort of raw Request object that has access to dynamic data - given that it's meant to serve as a generic REST/HTTP API that seems like a crucial missing piece. I don't see any way to read query string values either. To me personally HttpContext works, since I don't see myself using self-hosted code much.© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

Read the article

Can’t install Transport HUB in Exchange 2010

- by Kelly Jones

When building my latest SharePoint 2010 demo virtual machines, I decided to try installing Exchange 2010 as well. Now, I’m not an Exchange admin, but I thought “how hard can this be?” Well, a little more than I thought. Pretty early during the install, I got an error saying that it couldn’t “install Transport HUB”. I double checked that my VM was meeting all of the requirements, both hardware and software, and everything looked fine. After much researching, it turns out that the error was caused by not having IPv6 enabled on the network adapter inside the virtual machine. I had turned it off because I thought I wouldn’t need it. I guess Exchange 2010 does.

Read the article

Setup a vpn server on Ubuntu server, but client can't setup a connection

- by Jing

I setup a vpn server using pptpd on the ubuntu server which is installed in a virtual box machine on a windows 7 desktop. I configure the vpn server and port forwarding in the windows. However, I cannot setup a connection to the server. Here's the ubuntu log I got when I tried to connect to this vpn server Anyone can help me solve this problem? Also, is there any alternative way to setup a vpn server on windows or virtual machine installed on windows? Thanks!

Read the article

My View on ASP.NET Web Forms versus MVC

- by Ricardo Peres

Introduction A lot has been said on Web Forms and MVC, but since I was recently asked about my opinion on the subject, here it is. First, I have to say that I really like both technologies and I don’t think any is going away – just remember SharePoint, which is built on top of Web Forms. I see them as complementary, targeting different needs and leveraging different skills. Let’s go through some of their differences. Rapid Application Development Rapid Application Development (RAD) is the development process by which you have an Integrated Development Environment (IDE), a visual design surface and a toolbox, and you drag components from the toolbox to the design surface and set their properties through a property inspector. It was introduced with some of the earliest Windows graphical IDEs such as Visual Basic and Delphi. With Web Forms you have RAD out of the box. Visual Studio offers a generally good (and extensible) designer for the layout of pages and web user controls. Designing a page may simply be about dragging controls from the toolbox, setting their properties and wiring up some events to event handlers, which are implemented in code behind .NET classes. Most people will be familiar with this kind of development and enjoy it. You can see what you are doing from the beginning. MVC also has designable pages – called views in MVC terminology – the problem is that they can be built using different technologies, some of which, at the moment (MVC 4) do not support RAD – Razor, for example. I believe it is just a matter of time for that to be implemented in Visual Studio, but it will mostly consist on HTML editing, and until that day comes, you have to live with source editing. Development Model Web Forms features the same development model that you are used to from Windows Forms and other similar technologies: events fired by controls and automatic persistence of their properties between postbacks. For that, it uses concepts such as view state, which some may love and others may hate, because it may be misused quite easily, but otherwise does its job well. Another fundamental concept is data binding, by which a collection of data can be fed to a control and have it render that data somehow – just thing of the GridView control. The focus is on the page, that’s where it all starts, and you can place everything in the same code behind class: data access, business logic, layout, etc. The controls take care of generating a great part of the HTML and JavaScript for you. With MVC there is no free lunch when it comes to data persistence between requests, you have to implement it yourself. As for event handling, that is at the core of MVC, in the form of controllers and action methods, you just don’t think of them as event handlers. In MVC you need to think more in HTTP terms, so action methods such as POST and GET are relevant to you, and may write actions to handle one or the other. Also of crucial importance is model binding: the way by which MVC converts your posted data into a .NET class. This is something that ASP.NET 4.5 Web Forms has introduced as well, but it is a cornerstone in MVC. MVC also has built-in validation of these .NET classes, which out of the box uses the Data Annotations API. You have full control of the generated HTML - except for that coming from the helper methods, usually small fragments - which requires a greater familiarity with the specifications. You normally rely much more on JavaScript APIs, they are even included in the Visual Studio template, that is because much less is done for you. Reuse It is difficult to accept a professional company/project that does not employ reuse. It can save a lot of time thus cutting costs significantly. Code reused in several projects matures as time goes by and helps developers learn from past experiences. ASP.NET Web Forms was built with reuse in mind, in the form of controls. Controls encapsulate functionality and are generally portable from project to project (with the notable exception of web user controls, those with an associated .ASCX markup file). ASP.NET has dozens of controls and it is very easy to develop new ones, so I believe this is a great advantage. A control can inject JavaScript code and external references as well as generate HTML an CSS. MVC on the other hand does not use controls – it is possible to use them, with some view engines like ASPX, but it is just not advisable because it breaks the flow – where do Init, Load, PreRender, etc, fit? The most similar to controls is extension methods, or helpers. They serve the same purpose – generating HTML, CSS or JavaScript – and can be reused between different projects. What differentiates them from controls is that there is no inheritance and no context – an extension method is just a static method which doesn’t know where it is being called. You also have partial views, which you can reuse in the same project, but there is no inheritance as well. This, in my view, is a weakness of MVC. Architecture Both technologies are highly extensible. I have writtenstarted writing a series of posts on ASP.NET Web Forms extensibility and will probably write another series on MVC extensibility as well. A number of scenarios are covered in any of these models, and some extensibility points apply to both, because, of course both stand upon ASP.NET. With Web Forms, if you’re like me, you start by defining you master pages, pages and controls, with some helper classes to glue everything. You may as well throw in some JavaScript, but probably you’re main work will be with plain old .NET code. The controls you define have the chance to inject JavaScript code and references, through either the ScriptManager or the page’s ClientScript object, as well as generating HTML and CSS code. The master page and page model with code behind classes offer a number of “hooks” by which you can change the normal way of things, for example, in a page you can access any control on the master page, add script or stylesheet references to its head and even change the page’s title. Also, with Web Forms, you typically have URLs in the form “/SomePath/SomePage.aspx?SomeParameter=SomeValue”, which isn’t really SEO friendly, no to mention the HTML that some controls produce, far from standards, optimization and best practices. In MVC, you also normally start by defining the master page (or layout) and views, which are the visible parts, and then define controllers on separate files. These controllers do not know anything about the views, except the names and types of the parameters that will be passed to and from them. The controller will be responsible for the data access and business logic, eventually relying on additional classes for this purpose. On a controller you only receive parameters and return a result, which may be a request for the rendering of a view, a redirection to another URL or a JSON object, to name just a few. The controller class does not know anything about the web, so you can effectively reuse it in a non-web project. This separation and the lack of programmatic access to the UI elements, makes it very difficult to implement, for example, something like SharePoint with MVC. OK, I know about Orchard, but it isn’t really a general purpose development framework, but instead, a CMS that happens to use MVC. Not having controls render HTML for you gives you in turn much more control over it – it is your responsibility to create it, which you can either consider a blessing or a curse, in the later case, you probably shouldn’t be using MVC at all. Also MVC URLs tend to be much more SEO-oriented, if you design your controllers and actions properly. Testing In a well defined architecture, you should separate business logic, data access logic and presentation logic, because these are all different things and it might even be the need to switch one implementation for another: for example, you might design a system which includes a data access layer, a business logic layer and two presentation layers, one on top of ASP.NET and the other with WPF; and the data access layer might be implemented first using NHibernate and later on switched for Entity Framework Code First. These changes are not that rare, so care should be taken in designing the system to make them possible. Web Forms are difficult to test, because it relies on event handlers which are only fired in web contexts, when a form is submitted or a page is requested. You can call them with reflection, but you have to set up a number of mocking objects first, HttpContext.Current first coming to my mind. MVC, on the other hand, makes testing controllers a breeze, so much that it even includes a template option for generating boilerplate unit test classes up from start. A well designed – from the unit test point of view - controller will receive everything it needs to work as parameters to its action methods, so you can pass whatever values you need very easily. That doesn’t mean, of course, that everything can be tested: views, for instance, are difficult to test without actually accessing the site, but MVC offers the possibility to compile views at build time, so that, at least, you know you don’t have syntax errors beforehand. Myths Some popular but unfounded myths around MVC include: You cannot use controls in MVC: not true, actually, you can, at least with the Web Forms (ASPX) view engine; the declaration and usage is exactly the same as with Web Forms; You cannot specify a base class for a view: with the ASPX view engine you can use the Inherits Page directive, with this and all the others you can use the pageBaseType and userControlBaseType attributes of the <page> element; MVC shields you from doing “bad things” on your views: well, you can place any code on a code block, at least with the ASPX view engine (you may be starting to see a pattern here), even data access code; The model is the entity model, tied to an O/RM: the model is actually any class that you use to pass values to a view, including (but generally not recommended) an entity model; Unit tests come with no cost: unit tests generally don’t cover the UI, although there are frameworks just for that (see WatiN, for example); also, for some tests, you will have to mock or replace either the HttpContext.Current property or the HttpContextBase class yourself; Everything is testable: views aren’t, without accessing the site; MVC relies on HTML5/some_cool_new_javascript_framework: there is no relation whatsoever, MVC renders whatever you want it to render and does not require any framework to be present. The thing is, the subsequent releases of MVC happened in a time when Microsoft has become much more involved in standards, so the files and technologies included in the Visual Studio templates reflect this, and it just happens to work well with jQuery, for example. Conclusion Well, this is how I see it. Some folks may think that I am being too rude on MVC, probably because I don’t like it, but that’s not true: like I said, I do like MVC and I am starting my new projects with it. I just don’t want to go along with that those that say that MVC is much superior to Web Forms, in fact, some things you can do much more easily with Web Forms than with MVC. I will be more than happy to hear what you think on this!

Read the article

ASP.NET Web API - Screencast series Part 4: Paging and Querying

- by Jon Galloway

We're continuing a six part series on ASP.NET Web API that accompanies the getting started screencast series. This is an introductory screencast series that walks through from File / New Project to some more advanced scenarios like Custom Validation and Authorization. The screencast videos are all short (3-5 minutes) and the sample code for the series is both available for download and browsable online. I did the screencasts, but the samples were written by the ASP.NET Web API team. In Part 1 we looked at what ASP.NET Web API is, why you'd care, did the File / New Project thing, and did some basic HTTP testing using browser F12 developer tools. In Part 2 we started to build up a sample that returns data from a repository in JSON format via GET methods. In Part 3, we modified data on the server using DELETE and POST methods. In Part 4, we'll extend on our simple querying methods form Part 2, adding in support for paging and querying. This part shows two approaches to querying data (paging really just being a specific querying case) - you can do it yourself using parameters passed in via querystring (as well as headers, other route parameters, cookies, etc.). You're welcome to do that if you'd like. What I think is more interesting here is that Web API actions that return IQueryable automatically support OData query syntax, making it really easy to support some common query use cases like paging and filtering. A few important things to note: This is just support for OData query syntax - you're not getting back data in OData format. The screencast demonstrates this by showing the GET methods are continuing to return the same JSON they did previously. So you don't have to "buy in" to the whole OData thing, you're just able to use the query syntax if you'd like. This isn't full OData query support - full OData query syntax includes a lot of operations and features - but it is a pretty good subset: filter, orderby, skip, and top. All you have to do to enable this OData query syntax is return an IQueryable rather than an IEnumerable. Often, that could be as simple as using the AsQueryable() extension method on your IEnumerable. Query composition support lets you layer queries intelligently. If, for instance, you had an action that showed products by category using a query in your repository, you could also support paging on top of that. The result is an expression tree that's evaluated on-demand and includes both the Web API query and the underlying query. So with all those bullet points and big words, you'd think this would be hard to hook up. Nope, all I did was change the return type from IEnumerable<Comment> to IQueryable<Comment> and convert the Get() method's IEnumerable result using the .AsQueryable() extension method. public IQueryable<Comment> GetComments() { return repository.Get().AsQueryable(); } You still need to build up the query to provide the $top and $skip on the client, but you'd need to do that regardless. Here's how that looks: $(function () { //--------------------------------------------------------- // Using Queryable to page //--------------------------------------------------------- $("#getCommentsQueryable").click(function () { viewModel.comments([]); var pageSize = $('#pageSize').val(); var pageIndex = $('#pageIndex').val(); var url = "/api/comments?$top=" + pageSize + '&$skip=' + (pageIndex * pageSize); $.getJSON(url, function (data) { // Update the Knockout model (and thus the UI) with the comments received back // from the Web API call. viewModel.comments(data); }); return false; }); }); And the neat thing is that - without any modification to our server-side code - we can modify the above jQuery call to request the comments be sorted by author: $(function () { //--------------------------------------------------------- // Using Queryable to page //--------------------------------------------------------- $("#getCommentsQueryable").click(function () { viewModel.comments([]); var pageSize = $('#pageSize').val(); var pageIndex = $('#pageIndex').val(); var url = "/api/comments?$top=" + pageSize + '&$skip=' + (pageIndex * pageSize) + '&$orderby=Author'; $.getJSON(url, function (data) { // Update the Knockout model (and thus the UI) with the comments received back // from the Web API call. viewModel.comments(data); }); return false; }); }); So if you want to make use of OData query syntax, you can. If you don't like it, you're free to hook up your filtering and paging however you think is best. Neat. In Part 5, we'll add on support for Data Annotation based validation using an Action Filter.

Search Results

Search found 20586 results on 824 pages for 'virtual methods'.

Page 219/824 | < Previous Page | 215 216 217 218 219 220 221 222 223 224 225 226 | Next Page >

- by Paulo Morgado

- by shiju

- by Uphaar Goyal

- by Elton Stoneman

- by Rachel

- by Stephen.Walther

- by charles.knapp

- by Rohit Gupta

- by slohui

- by mbridge

- by ruth.donohue

- by gertvdijk

- by Jalpesh P. Vadgama

- by Boris Karl Schlein

- by BigSack

- by jon

- by van

- by TATWORTH

- by Rick Strahl

- by Kelly Jones

- by Jing

- by Ricardo Peres

- by Jon Galloway

< Previous Page | 215 216 217 218 219 220 221 222 223 224 225 226 | Next Page >