Search Results

Search found 88156 results on 3527 pages for 'code contracts'.

Page 646/3527 | < Previous Page | 642 643 644 645 646 647 648 649 650 651 652 653  | Next Page >

• Q1 2010 New Feature: Paging with RadGridView for Silverlight and WPF

  We are glad to announce that the Q1 2010 Release has added another weapon to RadGridViews growing arsenal of features. This is the brand new RadDataPager control which provides the user interface for paging through a collection of data. The good news is that RadDataPager can be used to page any collection. It does not depend on RadGridView in any way, so you will be free to use it with the rest of your ItemsControls if you chose to do so. Before you read on, you might want to download the samples solution that I have attached. It contains a sample project for every scenario that I will discuss later on. Looking at the code while reading will make things much easier for you. There is something for everyone among the 10 Visual Studio projects that are included in the solution. So go and grab it. I. Paging essentials The single most important piece of software concerning paging in Silverlight is the System.ComponentModel.IPagedCollectionView interface. Those of you who are on the WPF front need not worry though. As you might already know, Teleriks Silverlight and WPF controls is share the same code-base. Since WPF does not contain a similar interface, Telerik has provided its own Telerik.Windows.Data.IPagedCollectionView. The IPagedCollectionView interface contains several important members which are used by RadGridView to perform the actual paging. Silverlight provides a default implementation of this interface which, naturally, is called PagedCollectionView. You should definitely take a look at its source code in case you are interested in what is going on under the hood. But this is not a prerequisite for our discussion. The WPF default implementation of the interface is Teleriks QueryableCollectionView which, among many other interfaces, implements IPagedCollectionView. II. No Paging In order to gradually build up my case, I will start with a very simple example that lacks paging whatsoever. It might sound stupid, but this will help us build on top of this paging-devoid example. Let us imagine that we have the simplest possible scenario. That is a simple IEnumerable and an ItemsControl that shows its contents. This will look like this: No Paging IEnumerable itemsSource = Enumerable.Range(0, 1000); this.itemsControl.ItemsSource = itemsSource; XAML <Border Grid.Row="0" BorderBrush="Black" BorderThickness="1" Margin="5">     <ListBox Name="itemsControl"/> </Border> <Border Grid.Row="1" BorderBrush="Black" BorderThickness="1" Margin="5">     <TextBlock Text="No Paging"/> </Border> Nothing special for now. Just some data displayed in a ListBox. The two sample projects in the solution that I have attached are: NoPaging_WPF NoPaging_SL3 With every next sample those two project will evolve in some way or another. III. Paging simple collections The single most important property of RadDataPager is its Source property. This is where you pass in your collection of data for paging. More often than not your collection will not be an IPagedCollectionView. It will either be a simple List<T>, or an ObservableCollection<T>, or anything that is simply IEnumerable. Unless you had paging in mind when you designed your project, it is almost certain that your data source will not be pageable out of the box. So what are the options? III. 1. Wrapping the simple collection in an IPagedCollectionView If you look at the constructors of PagedCollectionView and QueryableCollectionView you will notice that you can pass in a simple IEnumerable as a parameter. Those two classes will wrap it and provide paging capabilities over your original data. In fact, this is what RadGridView does internally. It wraps your original collection in an QueryableCollectionView in order to easily perform many useful tasks such as filtering, sorting, and others, but in our case the most important one is paging. So let us start our series of examples with the most simplistic one. Imagine that you have a simple IEnumerable which is the source for an ItemsControl. Here is how to wrap it in order to enable paging: Silverlight IEnumerable itemsSource = Enumerable.Range(0, 1000); var pagedSource = new PagedCollectionView(itemsSource); this.radDataPager.Source = pagedSource; this.itemsControl.ItemsSource = pagedSource; WPF IEnumerable itemsSource = Enumerable.Range(0, 1000); var pagedSource = new QueryableCollectionView(itemsSource); this.radDataPager.Source = pagedSource; this.itemsControl.ItemsSource = pagedSource; XAML <Border Grid.Row="0"         BorderBrush="Black"         BorderThickness="1"         Margin="5">     <ListBox Name="itemsControl"/> </Border> <Border Grid.Row="1"         BorderBrush="Black"         BorderThickness="1"         Margin="5">     <telerikGrid:RadDataPager Name="radDataPager"                               PageSize="10"                              IsTotalItemCountFixed="True"                              DisplayMode="All"/> This will do the trick. It is quite simple, isnt it? The two sample projects in the solution that I have attached are: PagingSimpleCollectionWithWrapping_WPF PagingSimpleCollectionWithWrapping_SL3 III. 2. Binding to RadDataPager.PagedSource In case you do not like this approach there is a better one. When you assign an IEnumerable as the Source of a RadDataPager it will automatically wrap it in a QueryableCollectionView and expose it through its PagedSource property. From then on, you can attach any number of ItemsControls to the PagedSource and they will be automatically paged. Here is how to do this entirely in XAML: Using RadDataPager.PagedSource <Border Grid.Row="0"         BorderBrush="Black"         BorderThickness="1" Margin="5">     <ListBox Name="itemsControl"              ItemsSource="{Binding PagedSource, ElementName=radDataPager}"/> </Border> <Border Grid.Row="1"         BorderBrush="Black"         BorderThickness="1"         Margin="5">     <telerikGrid:RadDataPager Name="radDataPager"                               Source="{Binding ItemsSource}"                              PageSize="10"                              IsTotalItemCountFixed="True"                              DisplayMode="All"/> The two sample projects in the solution that I have attached are: PagingSimpleCollectionWithPagedSource_WPF PagingSimpleCollectionWithPagedSource_SL3 IV. Paging collections implementing IPagedCollectionView Those of you who are using WCF RIA Services should feel very lucky. After a quick look with Reflector or the debugger we can see that the DomainDataSource.Data property is in fact an instance of the DomainDataSourceView class. This class implements a handful of useful interfaces: ICollectionView IEnumerable INotifyCollectionChanged IEditableCollectionView IPagedCollectionView INotifyPropertyChanged Luckily, IPagedCollectionView is among them which lets you do the whole paging in the server. So lets do this. We will add a DomainDataSource control to our page/window and connect the items control and the pager to it. Here is how to do this: MainPage <riaControls:DomainDataSource x:Name="invoicesDataSource"                               AutoLoad="True"                               QueryName="GetInvoicesQuery">     <riaControls:DomainDataSource.DomainContext>         <services:ChinookDomainContext/>     </riaControls:DomainDataSource.DomainContext> </riaControls:DomainDataSource> <Border Grid.Row="0"         BorderBrush="Black"         BorderThickness="1"         Margin="5">     <ListBox Name="itemsControl"              ItemsSource="{Binding Data, ElementName=invoicesDataSource}"/> </Border> <Border Grid.Row="1"         BorderBrush="Black"         BorderThickness="1"         Margin="5">     <telerikGrid:RadDataPager Name="radDataPager"                               Source="{Binding Data, ElementName=invoicesDataSource}"                              PageSize="10"                              IsTotalItemCountFixed="True"                              DisplayMode="All"/> By the way, you can replace the ListBox from the above code snippet with any other ItemsControl. It can be RadGridView, it can be the MS DataGrid, you name it. Essentially, RadDataPager is sending paging commands to the the DomainDataSource.Data. It does not care who, what, or how many different controls are bound to this same Data property of the DomainDataSource control. So if you would like to experiment with this, you can throw in any number of other ItemsControls next to the ListBox, bind them in the same manner, and all of them will be paged by our single RadDataPager. Furthermore, you can throw in any number of RadDataPagers and bind them to the same property. Then when you page with any one of them will automatically update all of the rest. The whole picture is simply beautiful and we can do all of this thanks to WCF RIA Services. The two sample projects (Silverlight only) in the solution that I have attached are: PagingIPagedCollectionView PagingIPagedCollectionView.Web IV. Paging RadGridView While you can replace the ListBox in any of the above examples with a RadGridView, RadGridView offers something extra. Similar to the DomainDataSource.Data property, the RadGridView.Items collection implements the IPagedCollectionView interface. So you are already thinking: Then why not bind the Source property of RadDataPager to RadGridView.Items? Well thats exactly what you can do and you will start paging RadGridView out-of-the-box. It is as simple as that, no code-behind is involved: MainPage <Border Grid.Row="0"         BorderBrush="Black"         BorderThickness="1" Margin="5">     <telerikGrid:RadGridView Name="radGridView"                              ItemsSource="{Binding ItemsSource}"/> </Border> <Border Grid.Row="1"         BorderBrush="Black"         BorderThickness="1"         Margin="5">     <telerikGrid:RadDataPager Name="radDataPager"                               Source="{Binding Items, ElementName=radGridView}"                              PageSize="10"                              IsTotalItemCountFixed="True"                              DisplayMode="All"/> The two sample projects in the solution that I have attached are: PagingRadGridView_SL3 PagingRadGridView_WPF With this last example I think I have covered every possible paging combination. In case you would like to see an example of something that I have not covered, please let me know. Also, make sure you check out those great online examples: WCF RIA Services with DomainDataSource Paging Configurator Endless Paging Paging Any Collection Paging RadGridView Happy Paging! Download Full Source Code Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

  Read the article

• Dependency Injection in ASP.NET Web API using Autofac

  - by shiju

  In this post, I will demonstrate how to use Dependency Injection in ASP.NET Web API using Autofac in an ASP.NET MVC 4 app. The new ASP.NET Web API is a great framework for building HTTP services. The Autofac IoC container provides the better integration with ASP.NET Web API for applying dependency injection. The NuGet package Autofac.WebApi provides the  Dependency Injection support for ASP.NET Web API services. Using Autofac in ASP.NET Web API The following command in the Package Manager console will install Autofac.WebApi package into your ASP.NET Web API application. PM > Install-Package Autofac.WebApi The following code block imports the necessary namespaces for using Autofact.WebApi using Autofac; using Autofac.Integration.WebApi; .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The following code in the Bootstrapper class configures the Autofac. 1: public static class Bootstrapper 2: { 3: public static void Run() 4: { 5: SetAutofacWebAPI(); 6: } 7: private static void SetAutofacWebAPI() 8: { 9: var configuration = GlobalConfiguration.Configuration; 10: var builder = new ContainerBuilder(); 11: // Configure the container 12: builder.ConfigureWebApi(configuration); 13: // Register API controllers using assembly scanning. 14: builder.RegisterApiControllers(Assembly.GetExecutingAssembly()); 15: builder.RegisterType<DefaultCommandBus>().As<ICommandBus>() 16: .InstancePerApiRequest(); 17: builder.RegisterType<UnitOfWork>().As<IUnitOfWork>() 18: .InstancePerApiRequest(); 19: builder.RegisterType<DatabaseFactory>().As<IDatabaseFactory>() 20: .InstancePerApiRequest(); 21: builder.RegisterAssemblyTypes(typeof(CategoryRepository) 22: .Assembly).Where(t => t.Name.EndsWith("Repository")) 23: .AsImplementedInterfaces().InstancePerApiRequest(); 24: var services = Assembly.Load("EFMVC.Domain"); 25: builder.RegisterAssemblyTypes(services) 26: .AsClosedTypesOf(typeof(ICommandHandler<>)) 27: .InstancePerApiRequest(); 28: builder.RegisterAssemblyTypes(services) 29: .AsClosedTypesOf(typeof(IValidationHandler<>)) 30: .InstancePerApiRequest(); 31: var container = builder.Build(); 32: // Set the WebApi dependency resolver. 33: var resolver = new AutofacWebApiDependencyResolver(container); 34: configuration.ServiceResolver.SetResolver(resolver); 35: } 36: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The RegisterApiControllers method will scan the given assembly and register the all ApiController classes. This method will look for types that derive from IHttpController with name convention end with “Controller”. The InstancePerApiRequest method specifies the life time of the component for once per API controller invocation. The GlobalConfiguration.Configuration provides a ServiceResolver class which can be use set dependency resolver for ASP.NET Web API. In our example, we are using AutofacWebApiDependencyResolver class provided by Autofac.WebApi to set the dependency resolver. The Run method of Bootstrapper class is calling from Application_Start method of Global.asax.cs. 1: protected void Application_Start() 2: { 3: AreaRegistration.RegisterAllAreas(); 4: RegisterGlobalFilters(GlobalFilters.Filters); 5: RegisterRoutes(RouteTable.Routes); 6: BundleTable.Bundles.RegisterTemplateBundles(); 7: //Call Autofac DI configurations 8: Bootstrapper.Run(); 9: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Autofac.Mvc4 The Autofac framework’s integration with ASP.NET MVC has updated for ASP.NET MVC 4. The NuGet package Autofac.Mvc4 provides the dependency injection support for ASP.NET MVC 4. There is not any syntax change between Autofac.Mvc3 and Autofac.Mvc4 Source Code I have updated my EFMVC app with Autofac.WebApi for applying dependency injection for it’s ASP.NET Web API services. EFMVC app also updated to Autofac.Mvc4 for it’s ASP.NET MVC 4 web app. The above code sample is taken from the EFMVC app. You can download the source code of EFMVC app from http://efmvc.codeplex.com/

  Read the article

• Creating a dynamic proxy generator – Part 1 – Creating the Assembly builder, Module builder and cach

  - by SeanMcAlinden

  I’ve recently started a project with a few mates to learn the ins and outs of Dependency Injection, AOP and a number of other pretty crucial patterns of development as we’ve all been using these patterns for a while but have relied totally on third part solutions to do the magic. We thought it would be interesting to really get into the details by rolling our own IoC container and hopefully learn a lot on the way, and you never know, we might even create an excellent framework. The open source project is called Rapid IoC and is hosted at http://rapidioc.codeplex.com/ One of the most interesting tasks for me is creating the dynamic proxy generator for enabling Aspect Orientated Programming (AOP). In this series of articles, I’m going to track each step I take for creating the dynamic proxy generator and I’ll try my best to explain what everything means - mainly as I’ll be using Reflection.Emit to emit a fair amount of intermediate language code (IL) to create the proxy types at runtime which can be a little taxing to read. It’s worth noting that building the proxy is without a doubt going to be slightly painful so I imagine there will be plenty of areas I’ll need to change along the way. Anyway lets get started…   Part 1 - Creating the Assembly builder, Module builder and caching mechanism Part 1 is going to be a really nice simple start, I’m just going to start by creating the assembly, module and type caches. The reason we need to create caches for the assembly, module and types is simply to save the overhead of recreating proxy types that have already been generated, this will be one of the important steps to ensure that the framework is fast… kind of important as we’re calling the IoC container ‘Rapid’ – will be a little bit embarrassing if we manage to create the slowest framework. The Assembly builder The assembly builder is what is used to create an assembly at runtime, we’re going to have two overloads, one will be for the actual use of the proxy generator, the other will be mainly for testing purposes as it will also save the assembly so we can use Reflector to examine the code that has been created. Here’s the code: DynamicAssemblyBuilder using System; using System.Reflection; using System.Reflection.Emit; namespace Rapid.DynamicProxy.Assembly {     /// <summary>     /// Class for creating an assembly builder.     /// </summary>     internal static class DynamicAssemblyBuilder     {         #region Create           /// <summary>         /// Creates an assembly builder.         /// </summary>         /// <param name="assemblyName">Name of the assembly.</param>         public static AssemblyBuilder Create(string assemblyName)         {             AssemblyName name = new AssemblyName(assemblyName);               AssemblyBuilder assembly = AppDomain.CurrentDomain.DefineDynamicAssembly(                     name, AssemblyBuilderAccess.Run);               DynamicAssemblyCache.Add(assembly);               return assembly;         }           /// <summary>         /// Creates an assembly builder and saves the assembly to the passed in location.         /// </summary>         /// <param name="assemblyName">Name of the assembly.</param>         /// <param name="filePath">The file path.</param>         public static AssemblyBuilder Create(string assemblyName, string filePath)         {             AssemblyName name = new AssemblyName(assemblyName);               AssemblyBuilder assembly = AppDomain.CurrentDomain.DefineDynamicAssembly(                     name, AssemblyBuilderAccess.RunAndSave, filePath);               DynamicAssemblyCache.Add(assembly);               return assembly;         }           #endregion     } }   So hopefully the above class is fairly explanatory, an AssemblyName is created using the passed in string for the actual name of the assembly. An AssemblyBuilder is then constructed with the current AppDomain and depending on the overload used, it is either just run in the current context or it is set up ready for saving. It is then added to the cache.   DynamicAssemblyCache using System.Reflection.Emit; using Rapid.DynamicProxy.Exceptions; using Rapid.DynamicProxy.Resources.Exceptions;   namespace Rapid.DynamicProxy.Assembly {     /// <summary>     /// Cache for storing the dynamic assembly builder.     /// </summary>     internal static class DynamicAssemblyCache     {         #region Declarations           private static object syncRoot = new object();         internal static AssemblyBuilder Cache = null;           #endregion           #region Adds a dynamic assembly to the cache.           /// <summary>         /// Adds a dynamic assembly builder to the cache.         /// </summary>         /// <param name="assemblyBuilder">The assembly builder.</param>         public static void Add(AssemblyBuilder assemblyBuilder)         {             lock (syncRoot)             {                 Cache = assemblyBuilder;             }         }           #endregion           #region Gets the cached assembly                  /// <summary>         /// Gets the cached assembly builder.         /// </summary>         /// <returns></returns>         public static AssemblyBuilder Get         {             get             {                 lock (syncRoot)                 {                     if (Cache != null)                     {                         return Cache;                     }                 }                   throw new RapidDynamicProxyAssertionException(AssertionResources.NoAssemblyInCache);             }         }           #endregion     } } The cache is simply a static property that will store the AssemblyBuilder (I know it’s a little weird that I’ve made it public, this is for testing purposes, I know that’s a bad excuse but hey…) There are two methods for using the cache – Add and Get, these just provide thread safe access to the cache.   The Module Builder The module builder is required as the create proxy classes will need to live inside a module within the assembly. Here’s the code: DynamicModuleBuilder using System.Reflection.Emit; using Rapid.DynamicProxy.Assembly; namespace Rapid.DynamicProxy.Module {     /// <summary>     /// Class for creating a module builder.     /// </summary>     internal static class DynamicModuleBuilder     {         /// <summary>         /// Creates a module builder using the cached assembly.         /// </summary>         public static ModuleBuilder Create()         {             string assemblyName = DynamicAssemblyCache.Get.GetName().Name;               ModuleBuilder moduleBuilder = DynamicAssemblyCache.Get.DefineDynamicModule                 (assemblyName, string.Format("{0}.dll", assemblyName));               DynamicModuleCache.Add(moduleBuilder);               return moduleBuilder;         }     } } As you can see, the module builder is created on the assembly that lives in the DynamicAssemblyCache, the module is given the assembly name and also a string representing the filename if the assembly is to be saved. It is then added to the DynamicModuleCache. DynamicModuleCache using System.Reflection.Emit; using Rapid.DynamicProxy.Exceptions; using Rapid.DynamicProxy.Resources.Exceptions; namespace Rapid.DynamicProxy.Module {     /// <summary>     /// Class for storing the module builder.     /// </summary>     internal static class DynamicModuleCache     {         #region Declarations           private static object syncRoot = new object();         internal static ModuleBuilder Cache = null;           #endregion           #region Add           /// <summary>         /// Adds a dynamic module builder to the cache.         /// </summary>         /// <param name="moduleBuilder">The module builder.</param>         public static void Add(ModuleBuilder moduleBuilder)         {             lock (syncRoot)             {                 Cache = moduleBuilder;             }         }           #endregion           #region Get           /// <summary>         /// Gets the cached module builder.         /// </summary>         /// <returns></returns>         public static ModuleBuilder Get         {             get             {                 lock (syncRoot)                 {                     if (Cache != null)                     {                         return Cache;                     }                 }                   throw new RapidDynamicProxyAssertionException(AssertionResources.NoModuleInCache);             }         }           #endregion     } }   The DynamicModuleCache is very similar to the assembly cache, it is simply a statically stored module with thread safe Add and Get methods.   The DynamicTypeCache To end off this post, I’m going to create the cache for storing the generated proxy classes. I’ve spent a fair amount of time thinking about the type of collection I should use to store the types and have finally decided that for the time being I’m going to use a generic dictionary. This may change when I can actually performance test the proxy generator but the time being I think it makes good sense in theory, mainly as it pretty much maintains it’s performance with varying numbers of items – almost constant (0)1. Plus I won’t ever need to loop through the items which is not the dictionaries strong point. Here’s the code as it currently stands: DynamicTypeCache using System; using System.Collections.Generic; using System.Security.Cryptography; using System.Text; namespace Rapid.DynamicProxy.Types {     /// <summary>     /// Cache for storing proxy types.     /// </summary>     internal static class DynamicTypeCache     {         #region Declarations           static object syncRoot = new object();         public static Dictionary<string, Type> Cache = new Dictionary<string, Type>();           #endregion           /// <summary>         /// Adds a proxy to the type cache.         /// </summary>         /// <param name="type">The type.</param>         /// <param name="proxy">The proxy.</param>         public static void AddProxyForType(Type type, Type proxy)         {             lock (syncRoot)             {                 Cache.Add(GetHashCode(type.AssemblyQualifiedName), proxy);             }         }           /// <summary>         /// Tries the type of the get proxy for.         /// </summary>         /// <param name="type">The type.</param>         /// <returns></returns>         public static Type TryGetProxyForType(Type type)         {             lock (syncRoot)             {                 Type proxyType;                 Cache.TryGetValue(GetHashCode(type.AssemblyQualifiedName), out proxyType);                 return proxyType;             }         }           #region Private Methods           private static string GetHashCode(string fullName)         {             SHA1CryptoServiceProvider provider = new SHA1CryptoServiceProvider();             Byte[] buffer = Encoding.UTF8.GetBytes(fullName);             Byte[] hash = provider.ComputeHash(buffer, 0, buffer.Length);             return Convert.ToBase64String(hash);         }           #endregion     } } As you can see, there are two public methods, one for adding to the cache and one for getting from the cache. Hopefully they should be clear enough, the Get is a TryGet as I do not want the dictionary to throw an exception if a proxy doesn’t exist within the cache. Other than that I’ve decided to create a key using the SHA1CryptoServiceProvider, this may change but my initial though is the SHA1 algorithm is pretty fast to put together using the provider and it is also very unlikely to have any hashing collisions. (there are some maths behind how unlikely this is – here’s the wiki if you’re interested http://en.wikipedia.org/wiki/SHA_hash_functions)   Anyway, that’s the end of part 1 – although I haven’t started any of the fun stuff (by fun I mean hairpulling, teeth grating Relfection.Emit style fun), I’ve got the basis of the DynamicProxy in place so all we have to worry about now is creating the types, interceptor classes, method invocation information classes and finally a really nice fluent interface that will abstract all of the hard-core craziness away and leave us with a lightning fast, easy to use AOP framework. Hope you find the series interesting. All of the source code can be viewed and/or downloaded at our codeplex site - http://rapidioc.codeplex.com/ Kind Regards, Sean.

  Read the article

• Getting Started Building Windows 8 Store Apps with XAML/C#

  - by dwahlin

  Technology is fun isn’t it? As soon as you think you’ve figured out where things are heading a new technology comes onto the scene, changes things up, and offers new opportunities. One of the new technologies I’ve been spending quite a bit of time with lately is Windows 8 store applications. I posted my thoughts about Windows 8 during the BUILD conference in 2011 and still feel excited about the opportunity there. Time will tell how well it ends up being accepted by consumers but I’m hopeful that it’ll take off. I currently have two Windows 8 store application concepts I’m working on with one being built in XAML/C# and another in HTML/JavaScript. I really like that Microsoft supports both options since it caters to a variety of developers and makes it easy to get started regardless if you’re a desktop developer or Web developer. Here’s a quick look at how the technologies are organized in Windows 8: In this post I’ll focus on the basics of Windows 8 store XAML/C# apps by looking at features, files, and code provided by Visual Studio projects. To get started building these types of apps you’ll definitely need to have some knowledge of XAML and C#. Let’s get started by looking at the Windows 8 store project types available in Visual Studio 2012.   Windows 8 Store XAML/C# Project Types When you open Visual Studio 2012 you’ll see a new entry under C# named Windows Store. It includes 6 different project types as shown next.   The Blank App project provides initial starter code and a single page whereas the Grid App and Split App templates provide quite a bit more code as well as multiple pages for your application. The other projects available can be be used to create a class library project that runs in Windows 8 store apps, a WinRT component such as a custom control, and a unit test library project respectively. If you’re building an application that displays data in groups using the “tile” concept then the Grid App or Split App project templates are a good place to start. An example of the initial screens generated by each project is shown next: Grid App Split View App   When a user clicks a tile in a Grid App they can view details about the tile data. With a Split View app groups/categories are shown and when the user clicks on a group they can see a list of all the different items and then drill-down into them:   For the remainder of this post I’ll focus on functionality provided by the Blank App project since it provides a simple way to get started learning the fundamentals of building Windows 8 store apps.   Blank App Project Walkthrough The Blank App project is a great place to start since it’s simple and lets you focus on the basics. In this post I’ll focus on what it provides you out of the box and cover additional details in future posts. Once you have the basics down you can move to the other project types if you need the functionality they provide. The Blank App project template does exactly what it says – you get an empty project with a few starter files added to help get you going. This is a good option if you’ll be building an app that doesn’t fit into the grid layout view that you see a lot of Windows 8 store apps following (such as on the Windows 8 start screen). I ended up starting with the Blank App project template for the app I’m currently working on since I’m not displaying data/image tiles (something the Grid App project does well) or drilling down into lists of data (functionality that the Split App project provides). The Blank App project provides images for the tiles and splash screen (you’ll definitely want to change these), a StandardStyles.xaml resource dictionary that includes a lot of helpful styles such as buttons for the AppBar (a special type of menu in Windows 8 store apps), an App.xaml file, and the app’s main page which is named MainPage.xaml. It also adds a Package.appxmanifest that is used to define functionality that your app requires, app information used in the store, plus more. The App.xaml, App.xaml.cs and StandardStyles.xaml Files The App.xaml file handles loading a resource dictionary named StandardStyles.xaml which has several key styles used throughout the application: <Application x:Class="BlankApp.App" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="using:BlankApp"> <Application.Resources> <ResourceDictionary> <ResourceDictionary.MergedDictionaries> <!-- Styles that define common aspects of the platform look and feel Required by Visual Studio project and item templates --> <ResourceDictionary Source="Common/StandardStyles.xaml"/> </ResourceDictionary.MergedDictionaries> </ResourceDictionary> </Application.Resources> </Application>   StandardStyles.xaml has style definitions for different text styles and AppBar buttons. If you scroll down toward the middle of the file you’ll see that many AppBar button styles are included such as one for an edit icon. Button styles like this can be used to quickly and easily add icons/buttons into your application without having to be an expert in design. <Style x:Key="EditAppBarButtonStyle" TargetType="ButtonBase" BasedOn="{StaticResource AppBarButtonStyle}"> <Setter Property="AutomationProperties.AutomationId" Value="EditAppBarButton"/> <Setter Property="AutomationProperties.Name" Value="Edit"/> <Setter Property="Content" Value="&#xE104;"/> </Style> Switching over to App.xaml.cs, it includes some code to help get you started. An OnLaunched() method is added to handle creating a Frame that child pages such as MainPage.xaml can be loaded into. The Frame has the same overall purpose as the one found in WPF and Silverlight applications - it’s used to navigate between pages in an application. /// <summary> /// Invoked when the application is launched normally by the end user. Other entry points /// will be used when the application is launched to open a specific file, to display /// search results, and so forth. /// </summary> /// <param name="args">Details about the launch request and process.</param> protected override void OnLaunched(LaunchActivatedEventArgs args) { Frame rootFrame = Window.Current.Content as Frame; // Do not repeat app initialization when the Window already has content, // just ensure that the window is active if (rootFrame == null) { // Create a Frame to act as the navigation context and navigate to the first page rootFrame = new Frame(); if (args.PreviousExecutionState == ApplicationExecutionState.Terminated) { //TODO: Load state from previously suspended application } // Place the frame in the current Window Window.Current.Content = rootFrame; } if (rootFrame.Content == null) { // When the navigation stack isn't restored navigate to the first page, // configuring the new page by passing required information as a navigation // parameter if (!rootFrame.Navigate(typeof(MainPage), args.Arguments)) { throw new Exception("Failed to create initial page"); } } // Ensure the current window is active Window.Current.Activate(); }   Notice that in addition to creating a Frame the code also checks to see if the app was previously terminated so that you can load any state/data that the user may need when the app is launched again. If you’re new to the lifecycle of Windows 8 store apps the following image shows how an app can be running, suspended, and terminated.   If the user switches from an app they’re running the app will be suspended in memory. The app may stay suspended or may be terminated depending on how much memory the OS thinks it needs so it’s important to save state in case the application is ultimately terminated and has to be started fresh. Although I won’t cover saving application state here, additional information can be found at http://msdn.microsoft.com/en-us/library/windows/apps/xaml/hh465099.aspx. Another method in App.xaml.cs named OnSuspending() is also included in App.xaml.cs that can be used to store state as the user switches to another application:   /// <summary> /// Invoked when application execution is being suspended. Application state is saved /// without knowing whether the application will be terminated or resumed with the contents /// of memory still intact. /// </summary> /// <param name="sender">The source of the suspend request.</param> /// <param name="e">Details about the suspend request.</param> private void OnSuspending(object sender, SuspendingEventArgs e) { var deferral = e.SuspendingOperation.GetDeferral(); //TODO: Save application state and stop any background activity deferral.Complete(); } The MainPage.xaml and MainPage.xaml.cs Files The Blank App project adds a file named MainPage.xaml that acts as the initial screen for the application. It doesn’t include anything aside from an empty <Grid> XAML element in it. The code-behind class named MainPage.xaml.cs includes a constructor as well as a method named OnNavigatedTo() that is called once the page is displayed in the frame.   /// <summary> /// An empty page that can be used on its own or navigated to within a Frame. /// </summary> public sealed partial class MainPage : Page { public MainPage() { this.InitializeComponent(); } /// <summary> /// Invoked when this page is about to be displayed in a Frame. /// </summary> /// <param name="e">Event data that describes how this page was reached. The Parameter /// property is typically used to configure the page.</param> protected override void OnNavigatedTo(NavigationEventArgs e) { } }   If you’re experienced with XAML you can switch to Design mode and start dragging and dropping XAML controls from the ToolBox in Visual Studio. If you prefer to type XAML you can do that as well in the XAML editor or while in split mode. Many of the controls available in WPF and Silverlight are included such as Canvas, Grid, StackPanel, and Border for layout. Standard input controls are also included such as TextBox, CheckBox, PasswordBox, RadioButton, ComboBox, ListBox, and more. MediaElement is available for rendering video or playing audio files. Some of the “common” XAML controls included out of the box are shown next:   Although XAML/C# Windows 8 store apps don’t include all of the functionality available in Silverlight 5, the core functionality required to build store apps is there with additional functionality available in open source projects such as Callisto (started by Microsoft’s Tim Heuer), Q42.WinRT, and others. Standard XAML data binding can be used to bind C# objects to controls, converters can be used to manipulate data during the data binding process, and custom styles and templates can be applied to controls to modify them. Although Visual Studio 2012 doesn’t support visually creating styles or templates, Expression Blend 5 handles that very well. To get started building the initial screen of a Windows 8 app you can start adding controls as mentioned earlier. Simply place them inside of the <Grid> element that’s included. You can arrange controls in a stacked manner using the StackPanel control, add a border around controls using the Border control, arrange controls in columns and rows using the Grid control, or absolutely position controls using the Canvas control. One of the controls that may be new to you is the AppBar. It can be used to add menu/toolbar functionality into a store app and keep the app clean and focused. You can place an AppBar at the top or bottom of the screen. A user on a touch device can swipe up to display the bottom AppBar or right-click when using a mouse. An example of defining an AppBar that contains an Edit button is shown next. The EditAppBarButtonStyle is available in the StandardStyles.xaml file mentioned earlier. <Page.BottomAppBar> <AppBar x:Name="ApplicationAppBar" Padding="10,0,10,0" AutomationProperties.Name="Bottom App Bar"> <Grid> <StackPanel x:Name="RightPanel" Orientation="Horizontal" Grid.Column="1" HorizontalAlignment="Right"> <Button x:Name="Edit" Style="{StaticResource EditAppBarButtonStyle}" Tag="Edit" /> </StackPanel> </Grid> </AppBar> </Page.BottomAppBar> Like standard XAML controls, the <Button> control in the AppBar can be wired to an event handler method in the MainPage.Xaml.cs file or even bound to a ViewModel object using “commanding” if your app follows the Model-View-ViewModel (MVVM) pattern (check out the MVVM Light package available through NuGet if you’re using MVVM with Windows 8 store apps). The AppBar can be used to navigate to different screens, show and hide controls, display dialogs, show settings screens, and more.   The Package.appxmanifest File The Package.appxmanifest file contains configuration details about your Windows 8 store app. By double-clicking it in Visual Studio you can define the splash screen image, small and wide logo images used for tiles on the start screen, orientation information, and more. You can also define what capabilities the app has such as if it uses the Internet, supports geolocation functionality, requires a microphone or webcam, etc. App declarations such as background processes, file picker functionality, and sharing can also be defined Finally, information about how the app is packaged for deployment to the store can also be defined. Summary If you already have some experience working with XAML technologies you’ll find that getting started building Windows 8 applications is pretty straightforward. Many of the controls available in Silverlight and WPF are available making it easy to get started without having to relearn a lot of new technologies. In the next post in this series I’ll discuss additional features that can be used in your Windows 8 store apps.

  Read the article

• Enterprise Library Logging / Exception handling and Postsharp

  - by subodhnpushpak

  One of my colleagues came-up with a unique situation where it was required to create log files based on the input file which is uploaded. For example if A.xml is uploaded, the corresponding log file should be A_log.txt. I am a strong believer that Logging / EH / caching are cross-cutting architecture aspects and should be least invasive to the business-logic written in enterprise application. I have been using Enterprise Library for logging / EH (i use to work with Avanade, so i have affection towards the library!! :D ). I have been also using excellent library called PostSharp for cross cutting aspect. Here i present a solution with and without PostSharp all in a unit test. Please see full source code at end of the this blog post. But first, we need to tweak the enterprise library so that the log files are created at runtime based on input given. Below is Custom trace listner which writes log into a given file extracted out of Logentry extendedProperties property. using Microsoft.Practices.EnterpriseLibrary.Common.Configuration; using Microsoft.Practices.EnterpriseLibrary.Logging.Configuration; using Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners; using Microsoft.Practices.EnterpriseLibrary.Logging; using System.IO; using System.Text; using System; using System.Diagnostics;   namespace Subodh.Framework.Logging { [ConfigurationElementType(typeof(CustomTraceListenerData))] public class LogToFileTraceListener : CustomTraceListener {   private static object syncRoot = new object();   public override void TraceData(TraceEventCache eventCache, string source, TraceEventType eventType, int id, object data) {   if ((data is LogEntry) & this.Formatter != null) { WriteOutToLog(this.Formatter.Format((LogEntry)data), (LogEntry)data); } else { WriteOutToLog(data.ToString(), (LogEntry)data); } }   public override void Write(string message) { Debug.Print(message.ToString()); }   public override void WriteLine(string message) { Debug.Print(message.ToString()); }   private void WriteOutToLog(string BodyText, LogEntry logentry) { try { //Get the filelocation from the extended properties if (logentry.ExtendedProperties.ContainsKey("filelocation")) { string fullPath = Path.GetFullPath(logentry.ExtendedProperties["filelocation"].ToString());   //Create the directory where the log file is written to if it does not exist. DirectoryInfo directoryInfo = new DirectoryInfo(Path.GetDirectoryName(fullPath));   if (directoryInfo.Exists == false) { directoryInfo.Create(); }   //Lock the file to prevent another process from using this file //as data is being written to it.   lock (syncRoot) { using (FileStream fs = new FileStream(fullPath, FileMode.Append, FileAccess.Write, FileShare.Write, 4096, true)) { using (StreamWriter sw = new StreamWriter(fs, Encoding.UTF8)) { Log(BodyText, sw); sw.Close(); } fs.Close(); } } } } catch (Exception ex) { throw new LoggingException(ex.Message, ex); } }   /// <summary> /// Write message to named file /// </summary> public static void Log(string logMessage, TextWriter w) { w.WriteLine("{0}", logMessage); } } }   The above can be “plugged into” the code using below configuration <loggingConfiguration name="Logging Application Block" tracingEnabled="true" defaultCategory="Trace" logWarningsWhenNoCategoriesMatch="true"> <listeners> <add listenerDataType="Microsoft.Practices.EnterpriseLibrary.Logging.Configuration.CustomTraceListenerData, Microsoft.Practices.EnterpriseLibrary.Logging, Version=4.1.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" traceOutputOptions="None" filter="All" type="Subodh.Framework.Logging.LogToFileTraceListener, Subodh.Framework.Logging, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" name="Subodh Custom Trace Listener" initializeData="" formatter="Text Formatter" /> </listeners> Similarly we can use PostSharp to expose the above as cross cutting aspects as below using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Reflection; using PostSharp.Laos; using System.Diagnostics; using GC.FrameworkServices.ExceptionHandler; using Subodh.Framework.Logging;   namespace Subodh.Framework.ExceptionHandling { [Serializable] public sealed class LogExceptionAttribute : OnExceptionAspect { private string prefix; private MethodFormatStrings formatStrings;   // This field is not serialized. It is used only at compile time. [NonSerialized] private readonly Type exceptionType; private string fileName;   /// <summary> /// Declares a <see cref="XTraceExceptionAttribute"/> custom attribute /// that logs every exception flowing out of the methods to which /// the custom attribute is applied. /// </summary> public LogExceptionAttribute() { }   /// <summary> /// Declares a <see cref="XTraceExceptionAttribute"/> custom attribute /// that logs every exception derived from a given <see cref="Type"/> /// flowing out of the methods to which /// the custom attribute is applied. /// </summary> /// <param name="exceptionType"></param> public LogExceptionAttribute( Type exceptionType ) { this.exceptionType = exceptionType; }   public LogExceptionAttribute(Type exceptionType, string fileName) { this.exceptionType = exceptionType; this.fileName = fileName; }   /// <summary> /// Gets or sets the prefix string, printed before every trace message. /// </summary> /// <value> /// For instance <c>[Exception]</c>. /// </value> public string Prefix { get { return this.prefix; } set { this.prefix = value; } }   /// <summary> /// Initializes the current object. Called at compile time by PostSharp. /// </summary> /// <param name="method">Method to which the current instance is /// associated.</param> public override void CompileTimeInitialize( MethodBase method ) { // We just initialize our fields. They will be serialized at compile-time // and deserialized at runtime. this.formatStrings = Formatter.GetMethodFormatStrings( method ); this.prefix = Formatter.NormalizePrefix( this.prefix ); }   public override Type GetExceptionType( MethodBase method ) { return this.exceptionType; }   /// <summary> /// Method executed when an exception occurs in the methods to which the current /// custom attribute has been applied. We just write a record to the tracing /// subsystem. /// </summary> /// <param name="context">Event arguments specifying which method /// is being called and with which parameters.</param> public override void OnException( MethodExecutionEventArgs context ) { string message = String.Format("{0}Exception {1} {{{2}}} in {{{3}}}. \r\n\r\nStack Trace {4}", this.prefix, context.Exception.GetType().Name, context.Exception.Message, this.formatStrings.Format(context.Instance, context.Method, context.GetReadOnlyArgumentArray()), context.Exception.StackTrace); if(!string.IsNullOrEmpty(fileName)) { ApplicationLogger.LogException(message, fileName); } else { ApplicationLogger.LogException(message, Source.UtilityService); } } } } To use the above below is the unit test [TestMethod] [ExpectedException(typeof(NotImplementedException))] public void TestMethod1() { MethodThrowingExceptionForLog(); try { MethodThrowingExceptionForLogWithPostSharp(); } catch (NotImplementedException ex) { throw ex; } }   private void MethodThrowingExceptionForLog() { try { throw new NotImplementedException(); } catch (NotImplementedException ex) { // create file and then write log ApplicationLogger.TraceMessage("this is a trace message which will be logged in Test1MyFile", @"D:\EL\Test1Myfile.txt"); ApplicationLogger.TraceMessage("this is a trace message which will be logged in YetAnotherTest1Myfile", @"D:\EL\YetAnotherTest1Myfile.txt"); } }   // Automatically log details using attributes // Log exception using attributes .... A La WCF [FaultContract(typeof(FaultMessage))] style] [Log(@"D:\EL\Test1MyfileLogPostsharp.txt")] [LogException(typeof(NotImplementedException), @"D:\EL\Test1MyfileExceptionPostsharp.txt")] private void MethodThrowingExceptionForLogWithPostSharp() { throw new NotImplementedException(); } The good thing about the approach is that all the logging and EH is done at centralized location controlled by PostSharp. Of Course, if some other library has to be used instead of EL, it can easily be plugged in. Also, the coder ARE ONLY involved in writing business code in methods, which makes code cleaner. Here is the full source code. The third party assemblies provided are from EL and PostSharp and i presume you will find these useful. Do let me know your thoughts / ideas on the same. Technorati Tags: PostSharp,Enterprize library,C#,Logging,Exception handling

  Read the article

• Another Marketing Conference, part two – the afternoon

  - by Roger Hart

  In my previous post, I’ve covered the morning sessions at AMC2012. Here’s the rest of the write-up. I’ve skipped Charles Nixon’s session which was a blend of funky futurism and professional development advice, but you can see his slides here. I’ve also skipped the Google presentation, as it was a little thin on insight. 6 – Brand ambassadors: Getting universal buy in across the organisation, Vanessa Northam Slides are here This was the strongest enforcement of the idea that brand and campaign values need to be delivered throughout the organization if they’re going to work. Vanessa runs internal communications at e-on, and shared her experience of using internal comms to align an organization and thereby get the most out of a campaign. She views the purpose of internal comms as: “…to help leaders, to communicate the purpose and future of an organization, and support change.” This (and culture) primes front line staff, which creates customer experience and spreads brand. You ensure a whole organization knows what’s going on with both internal and external comms. If everybody is aligned and informed, if everybody can clearly articulate your brand and campaign goals, then you can turn everybody into an advocate. Alignment is a powerful tool for delivering a consistent experience and message. The pathological counter example is the one in which a marketing message goes out, which creates inbound customer contacts that front line contact staff haven’t been briefed to handle. The NatWest campaign was again mentioned in this context. The good example was e-on’s cheaper tariff campaign. Building a groundswell of internal excitement, and even running an internal launch meant everyone could contribute to a good customer experience. They found that meter readers were excited – not a group they’d considered as obvious in providing customer experience. But they were a group that has a lot of face-to-face contact with customers, and often were asked questions they may not have been briefed to answer. Being able to communicate a simple new message made it easier for them, and also let them become a sales and marketing asset to the organization. 7 – Goodbye Internet, Hello Outernet: the rise and rise of augmented reality, Matt Mills I wasn’t going to write this up, because it was essentially a sales demo for Aurasma. But the technology does merit some discussion. Basically, it replaces QR codes with visual recognition, and provides a simple-looking back end for attaching content. It’s quite sexy. But here’s my beef with it: QR codes had a clear visual language – when you saw one you knew what it was and what to do with it. They were clunky, but they had the “getting started” problem solved out of the box once you knew what you were looking at. However, they fail because QR code reading isn’t native to the platform. You needed an app, which meant you needed to know to download one. Consequentially, you can’t use QR codes with and ubiquity, or depend on them. This means marketers, content providers, etc, never pushed them, and they remained and awkward oddity, a minority sport. Aurasma half solves problem two, and re-introduces problem one, making it potentially half as useful as a QR code. It’s free, and you can apparently build it into your own apps. Add to that the likelihood of it becoming native to the platform if it takes off, and it may have legs. I guess we’ll see. 8 – We all need to code, Helen Mayor Great title – good point. If there was anybody in the room who didn’t at least know basic HTML, and if Helen’s presentation inspired them to learn, that’s fantastic. However, this was a half hour sales pitch for a basic coding training course. Beyond advocating coding skills it contained no useful content. Marketers may also like to consider some of these resources if they’re looking to learn code: Code Academy – free interactive tutorials Treehouse – learn web design, web dev, or app dev WebPlatform.org – tutorials and documentation for web tech  11 – Understanding our inner creativity, Margaret Boden This session was the most theoretical and probably least actionable of the day. It also held my attention utterly. Margaret spoke fluently, fascinatingly, without slides, on the subject of types of creativity and how they work. It was splendid. Yes, it raised a wry smile whenever she spoke of “the content of advertisements” and gave an example from 1970s TV ads, but even without the attempt to meet the conference’s theme this would have been thoroughly engaging. There are, Margaret suggested, three types of creativity: Combinatorial creativity The most common form, and consisting of synthesising ideas from existing and familiar concepts and tropes. Exploratory creativity Less common, this involves exploring the limits and quirks of a particular constraint or style. Transformational creativity This is uncommon, and arises from finding a way to do something that the existing rules would hold to be impossible. In essence, this involves breaking one of the constraints that exploratory creativity is composed from. Combinatorial creativity, she suggested, is particularly important for attaching favourable ideas to existing things. As such is it probably worth developing for marketing. Exploratory creativity may then come into play in something like developing and optimising an idea or campaign that now has momentum. Transformational creativity exists at the edges of this exploration. She suggested that products may often be transformational, but that marketing seemed unlikely to in her experience. This made me wonder about Listerine. Crucially, transformational creativity is characterised by there being some element of continuity with the strictures of previous thinking. Once it has happened, there may be  move from a revolutionary instance into an explored style. Again, from a marketing perspective, this seems to chime well with the thinking in Youngme Moon’s book: Different Talking about the birth of Modernism is visual art, Margaret pointed out that transformational creativity has historically risked a backlash, demanding what is essentially an education of the market. This is best accomplished by referring back to the continuities with the past in order to make the new familiar. Thoughts The afternoon is harder to sum up than the morning. It felt less concrete, and was troubled by a short run of poor presentations in the middle. Mainly, I found myself wrestling with the internal comms issue. It’s one of those things that seems astonishingly obvious in hindsight, but any campaign – particularly any large one – is doomed if the people involved can’t believe in it. We’ve run things here that haven’t gone so well, of course we have; who hasn’t? I’m not going to air any laundry, but people not being informed (much less aligned) feels like a common factor. It’s tough though. Managing and anticipating information needs across an organization of any size can’t be easy. Even the simple things like ensuring sales and support departments know what’s in a product release, and what messages go with it are easy to botch. The thing I like about framing this as a brand and campaign advocacy problem is that it makes it likely to get addressed. Better is always sexier than less-worse. Any technical communicator who’s ever felt crowded out by a content strategist or marketing copywriter  knows this – increasing revenue gets a seat at the table far more readily than reducing support costs, even if the financial impact is identical. So that’s it from AMC. The big thought-provokers were social buying behaviour and eliciting behaviour change, and the value of internal communications in ensuring successful campaigns and continuity of customer experience. I’ll be chewing over that for a while, and I’d definitely return next year.      

  Read the article

• SSIS - XML Source Script

  - by simonsabin

  The XML Source in SSIS is great if you have a 1 to 1 mapping between entity and table. You can do more complex mapping but it becomes very messy and won't perform. What other options do you have? The challenge with XML processing is to not need a huge amount of memory. I remember using the early versions of Biztalk with loaded the whole document into memory to map from one document type to another. This was fine for small documents but was an absolute killer for large documents. You therefore need a streaming approach. For flexibility however you want to be able to generate your rows easily, and if you've ever used the XmlReader you will know its ugly code to write. That brings me on to LINQ. The is an implementation of LINQ over XML which is really nice. You can write nice LINQ queries instead of the XMLReader stuff. The downside is that by default LINQ to XML requires a whole XML document to work with. No streaming. Your code would look like this. We create an XDocument and then enumerate over a set of annoymous types we generate from our LINQ statement XDocument x = XDocument.Load("C:\\TEMP\\CustomerOrders-Attribute.xml");   foreach (var xdata in (from customer in x.Elements("OrderInterface").Elements("Customer")                        from order in customer.Elements("Orders").Elements("Order")                        select new { Account = customer.Attribute("AccountNumber").Value                                   , OrderDate = order.Attribute("OrderDate").Value }                        )) {     Output0Buffer.AddRow();     Output0Buffer.AccountNumber = xdata.Account;     Output0Buffer.OrderDate = Convert.ToDateTime(xdata.OrderDate); } As I said the downside to this is that you are loading the whole document into memory. I did some googling and came across some helpful videos from a nice UK DPE Mike Taulty http://www.microsoft.com/uk/msdn/screencasts/screencast/289/LINQ-to-XML-Streaming-In-Large-Documents.aspx. Which show you how you can combine LINQ and the XmlReader to get a semi streaming approach. I took what he did and implemented it in SSIS. What I found odd was that when I ran it I got different numbers between using the streamed and non streamed versions. I found the cause was a little bug in Mikes code that causes the pointer in the XmlReader to progress past the start of the element and thus foreach (var xdata in (from customer in StreamReader("C:\\TEMP\\CustomerOrders-Attribute.xml","Customer")                                from order in customer.Elements("Orders").Elements("Order")                                select new { Account = customer.Attribute("AccountNumber").Value                                           , OrderDate = order.Attribute("OrderDate").Value }                                ))         {             Output0Buffer.AddRow();             Output0Buffer.AccountNumber = xdata.Account;             Output0Buffer.OrderDate = Convert.ToDateTime(xdata.OrderDate);         } These look very similiar and they are the key element is the method we are calling, StreamReader. This method is what gives us streaming, what it does is return a enumerable list of elements, because of the way that LINQ works this results in the data being streamed in. static IEnumerable<XElement> StreamReader(String filename, string elementName) {     using (XmlReader xr = XmlReader.Create(filename))     {         xr.MoveToContent();         while (xr.Read()) //Reads the first element         {             while (xr.NodeType == XmlNodeType.Element && xr.Name == elementName)             {                 XElement node = (XElement)XElement.ReadFrom(xr);                   yield return node;             }         }         xr.Close();     } } This code is specifically designed to return a list of the elements with a specific name. The first Read reads the root element and then the inner while loop checks to see if the current element is the type we want. If not we do the xr.Read() again until we find the element type we want. We then use the neat function XElement.ReadFrom to read an element and all its sub elements into an XElement. This is what is returned and can be consumed by the LINQ statement. Essentially once one element has been read we need to check if we are still on the same element type and name (the inner loop) This was Mikes mistake, if we called .Read again we would advance the XmlReader beyond the start of the Element and so the ReadFrom method wouldn't work. So with the code above you can use what ever LINQ statement you like to flatten your XML into the rowsets you want. You could even have multiple outputs and generate your own surrogate keys.        

  Read the article

• Multi-tenant ASP.NET MVC - Views

  - by zowens

  Part I – Introduction Part II – Foundation Part III – Controllers   So far we have covered the basic premise of tenants and how they will be delegated. Now comes a big issue with multi-tenancy, the views. In some applications, you will not have to override views for each tenant. However, one of my requirements is to add extra views (and controller actions) along with overriding views from the core structure. This presents a bit of a problem in locating views for each tenant request. I have chosen quite an opinionated approach at the present but will coming back to the “views” issue in a later post. What’s the deal? The path I’ve chosen is to use precompiled Spark views. I really love Spark View Engine and was planning on using it in my project anyways. However, I ran across a really neat aspect of the source when I was having a look under the hood. There’s an easy way to hook in embedded views from your project. There are solutions that provide this, but they implement a special Virtual Path Provider. While I think this is a great solution, I would rather just have Spark take care of the view resolution. The magic actually happens during the compilation of the views into a bin-deployable DLL. After the views are compiled, the are simply pulled out of the views DLL. Each tenant has its own views DLL that just has “.Views” appended after the assembly name as a convention. The list of reasons for this approach are quite long. The primary motivation is performance. I’ve had quite a few performance issues in the past and I would like to increase my application’s performance in any way that I can. My customized build of Spark removes insignificant whitespace from the HTML output so I can some some bandwidth and load time without having to deal with whitespace removal at runtime.   How to setup Tenants for the Host In the source, I’ve provided a single tenant as a sample (Sample1). This will serve as a template for subsequent tenants in your application. The first step is to add a “PostBuildStep” installer into the project. I’ve defined one in the source that will eventually change as we focus more on the construction of dependency containers. The next step is to tell the project to run the installer and copy the DLL output to a folder in the host that will pick up as a tenant. Here’s the code that will achieve it (this belongs in Post-build event command line field in the Build Events tab of settings) %systemroot%\Microsoft.NET\Framework\v4.0.30319\installutil "$(TargetPath)" copy /Y "$(TargetDir)$(TargetName)*.dll" "$(SolutionDir)Web\Tenants\" copy /Y "$(TargetDir)$(TargetName)*.pdb" "$(SolutionDir)Web\Tenants\" The DLLs with a name starting with the target assembly name will be copied to the “Tenants” folder in the web project. This means something like MultiTenancy.Tenants.Sample1.dll and MultiTenancy.Tenants.Sample1.Views.dll will both be copied along with the debug symbols. This is probably the simplest way to go about this, but it is a tad inflexible. For example, what if you have dependencies? The preferred method would probably be to use IL Merge to merge your dependencies with your target DLL. This would have to be added in the build events. Another way to achieve that would be to simply bypass Visual Studio events and use MSBuild.   I also got a question about how I was setting up the controller factory. Here’s the basics on how I’m setting up tenants inside the host (Global.asax) protected void Application_Start() { RegisterRoutes(RouteTable.Routes); // create a container just to pull in tenants var topContainer = new Container(); topContainer.Configure(config => { config.Scan(scanner => { scanner.AssembliesFromPath(Path.Combine(Server.MapPath("~/"), "Tenants")); scanner.AddAllTypesOf<IApplicationTenant>(); }); }); // create selectors var tenantSelector = new DefaultTenantSelector(topContainer.GetAllInstances<IApplicationTenant>()); var containerSelector = new TenantContainerResolver(tenantSelector); // clear view engines, we don't want anything other than spark ViewEngines.Engines.Clear(); // set view engine ViewEngines.Engines.Add(new TenantViewEngine(tenantSelector)); // set controller factory ControllerBuilder.Current.SetControllerFactory(new ContainerControllerFactory(containerSelector)); } The code to setup the tenants isn’t actually that hard. I’m utilizing assembly scanners in StructureMap as a simple way to pull in DLLs that are not in the AppDomain. Remember that there is a dependency on the host in the tenants and a tenant cannot simply be referenced by a host because of circular dependencies.   Tenant View Engine TenantViewEngine is a simple delegator to the tenant’s specified view engine. You might have noticed that a tenant has to define a view engine. public interface IApplicationTenant { .... IViewEngine ViewEngine { get; } } The trick comes in specifying the view engine on the tenant side. Here’s some of the code that will pull views from the DLL. protected virtual IViewEngine DetermineViewEngine() { var factory = new SparkViewFactory(); var file = GetType().Assembly.CodeBase.Without("file:///").Replace(".dll", ".Views.dll").Replace('/', '\\'); var assembly = Assembly.LoadFile(file); factory.Engine.LoadBatchCompilation(assembly); return factory; } This code resides in an abstract Tenant where the fields are setup in the constructor. This method (inside the abstract class) will load the Views assembly and load the compilation into Spark’s “Descriptors” that will be used to determine views. There is some trickery on determining the file location… but it works just fine.   Up Next There’s just a few big things left such as StructureMap configuring controllers with a convention instead of specifying types directly with container construction and content resolution. I will also try to find a way to use the Web Forms View Engine in a multi-tenant way we achieved with the Spark View Engine without using a virtual path provider. I will probably not use the Web Forms View Engine personally, but I’m sure some people would prefer using WebForms because of the maturity of the engine. As always, I love to take questions by email or on twitter. Suggestions are always welcome as well! (Oh, and here’s another link to the source code).

  Read the article

• .NET 4.5 is an in-place replacement for .NET 4.0

  - by Rick Strahl

  With the betas for .NET 4.5 and Visual Studio 11 and Windows 8 shipping many people will be installing .NET 4.5 and hacking away on it. There are a number of great enhancements that are fairly transparent, but it's important to understand what .NET 4.5 actually is in terms of the CLR running on your machine. When .NET 4.5 is installed it effectively replaces .NET 4.0 on the machine. .NET 4.0 gets overwritten by a new version of .NET 4.5 which - according to Microsoft - is supposed to be 100% backwards compatible. While 100% backwards compatible sounds great, we all know that 100% is a hard number to hit, and even the aforementioned blog post at the Microsoft site acknowledges this. But there's so much more than backwards compatibility that makes this awkward at best and confusing at worst. What does ‘Replacement’ mean? When you install .NET 4.5 your .NET 4.0 assemblies in the \Windows\.NET Framework\V4.0.30319 are overwritten with a new set of assemblies. You end up with overwritten assemblies as well as a bunch of new ones (like the new System.Net.Http assemblies for example). The following screen shot demonstrates system.dll on my test machine (left) running .NET 4.5 on the right and my production laptop running stock .NET 4.0 (right):   Clearly they are different files with a difference in file sizes (interesting that the 4.5 version is actually smaller). That’s not all. If you actually query the runtime version when .NET 4.5 is installed with with Environment.Version you still get: 4.0.30319 If you open the properties of System.dll assembly in .NET 4.5 you'll also see: Notice that the file version is also left at 4.0.xxx. There are differences in build numbers: .NET 4.0 shows 261 and the current .NET 4.5 beta build is 17379. I suppose you can use assume a build number greater than 17000 is .NET 4.5, but that's pretty hokey to say the least. There’s no easy or obvious way to tell whether you are running on 4.0 or 4.5 – to the application they appear to be the same runtime version. And that is what Microsoft intends here. .NET 4.5 is intended as an in-place upgrade. Compile to 4.5 run on 4.0 – not quite! You can compile an application for .NET 4.5 and run it on the 4.0 runtime – that is until you hit a new feature that doesn’t exist on 4.0. At which point the app bombs at runtime. Say you write some code that is mostly .NET 4.0, but only has a few of the new features of .NET 4.5 like aync/await buried deep in the bowels of the application where it only fires occasionally. .NET will happily start your application and run everything 4.0 fine, until it hits that 4.5 code – and then crash unceremoniously at runtime. Oh joy! You can .NET 4.0 applications on .NET 4.5 of course and that should work without much fanfare. Different than .NET 3.0/3.5 Note that this in-place replacement is very different from the side by side installs of .NET 2.0 and 3.0/3.5 which all ran on the 2.0 version of the CLR. The two 3.x versions were basically library enhancements on top of the core .NET 2.0 runtime. Both versions ran under the .NET 2.0 runtime which wasn’t changed (other than for security patches and bug fixes) for the whole 3.x cycle. The 4.5 update instead completely replaces the .NET 4.0 runtime and leaves the actual version number set at v4.0.30319. When you build a new project with Visual Studio 2011, you can still target .NET 4.0 or you can target .NET 4.5. But you are in effect referencing the same set of assemblies for both regardless which version you use. What's different is the compiler used to compile and link your code so compiling with .NET 4.0 gives you just the subset of the functionality that is available in .NET 4.0, but when you use the 4.5 compiler you get the full functionality of what’s actually available in the assemblies and extra libraries. It doesn’t look like you will be able to use Visual Studio 2010 to develop .NET 4.5 applications. Good news – Bad news Microsoft is trying hard to experiment with every possible permutation of releasing new versions of the .NET framework apparently. No two updates have been the same. Clearly updating to a full new version of .NET (ie. .NET 2.0, 4.0 and at some point 5.0 runtimes) has its own set of challenges, but doing an in-place update of the runtime and then not even providing a good way to tell which version is installed is pretty whacky even by Microsoft’s standards. Especially given that .NET 4.5 includes a fairly significant update with all the aysnc functionality baked into the runtime. Most of the IO APIs have been updated to support task based async operation which significantly affects many existing APIs. To make things worse .NET 4.5 will be the initial version of .NET that ships with Windows 8 so it will be with us for a long time to come unless Microsoft finally decides to push .NET versions onto Windows machines as part of system upgrades (which currently doesn’t happen). This is the same story we had when Vista launched with .NET 3.0 which was a minor version that quickly was replaced by 3.5 which was more long lived and practical. People had enough problems dealing with the confusing versioning of the 3.x versions which ran on .NET 2.0. I can’t count the amount support calls and questions I’ve fielded because people couldn’t find a .NET 3.5 entry in the IIS version dialog. The same is likely to happen with .NET 4.5. It’s all well and good when we know that .NET 4.5 is an in-place replacement, but administrators and IT folks not intimately familiar with .NET are unlikely to understand this nuance and end up thoroughly confused which version is installed. It’s hard for me to see any upside to an in-place update and I haven’t really seen a good explanation of why this approach was decided on. Sure if the version stays the same existing assembly bindings don’t break so applications can stay running through an update. I suppose this is useful for some component vendors and strongly signed assemblies in corporate environments. But seriously, if you are going to throw .NET 4.5 into the mix, who won’t be recompiling all code and thoroughly test that code to work on .NET 4.5? A recompile requirement doesn’t seem that serious in light of a major version upgrade.  Resources http://blogs.msdn.com/b/dotnet/archive/2011/09/26/compatibility-of-net-framework-4-5.aspx http://www.devproconnections.com/article/net-framework/net-framework-45-versioning-faces-problems-141160© Rick Strahl, West Wind Technologies, 2005-2012Posted in .NET   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

• ParallelWork: Feature rich multithreaded fluent task execution library for WPF

  - by oazabir

  ParallelWork is an open source free helper class that lets you run multiple work in parallel threads, get success, failure and progress update on the WPF UI thread, wait for work to complete, abort all work (in case of shutdown), queue work to run after certain time, chain parallel work one after another. It’s more convenient than using .NET’s BackgroundWorker because you don’t have to declare one component per work, nor do you need to declare event handlers to receive notification and carry additional data through private variables. You can safely pass objects produced from different thread to the success callback. Moreover, you can wait for work to complete before you do certain operation and you can abort all parallel work while they are in-flight. If you are building highly responsive WPF UI where you have to carry out multiple job in parallel yet want full control over those parallel jobs completion and cancellation, then the ParallelWork library is the right solution for you. I am using the ParallelWork library in my PlantUmlEditor project, which is a free open source UML editor built on WPF. You can see some realistic use of the ParallelWork library there. Moreover, the test project comes with 400 lines of Behavior Driven Development flavored tests, that confirms it really does what it says it does. The source code of the library is part of the “Utilities” project in PlantUmlEditor source code hosted at Google Code. The library comes in two flavors, one is the ParallelWork static class, which has a collection of static methods that you can call. Another is the Start class, which is a fluent wrapper over the ParallelWork class to make it more readable and aesthetically pleasing code. ParallelWork allows you to start work immediately on separate thread or you can queue a work to start after some duration. You can start an immediate work in a new thread using the following methods: void StartNow(Action doWork, Action onComplete) void StartNow(Action doWork, Action onComplete, Action<Exception> failed) For example, ParallelWork.StartNow(() => { workStartedAt = DateTime.Now; Thread.Sleep(howLongWorkTakes); }, () => { workEndedAt = DateTime.Now; }); Or you can use the fluent way Start.Work: Start.Work(() => { workStartedAt = DateTime.Now; Thread.Sleep(howLongWorkTakes); }) .OnComplete(() => { workCompletedAt = DateTime.Now; }) .Run(); Besides simple execution of work on a parallel thread, you can have the parallel thread produce some object and then pass it to the success callback by using these overloads: void StartNow<T>(Func<T> doWork, Action<T> onComplete) void StartNow<T>(Func<T> doWork, Action<T> onComplete, Action<Exception> fail) For example, ParallelWork.StartNow<Dictionary<string, string>>( () => { test = new Dictionary<string,string>(); test.Add("test", "test"); return test; }, (result) => { Assert.True(result.ContainsKey("test")); }); Or, the fluent way: Start<Dictionary<string, string>>.Work(() => { test = new Dictionary<string, string>(); test.Add("test", "test"); return test; }) .OnComplete((result) => { Assert.True(result.ContainsKey("test")); }) .Run(); You can also start a work to happen after some time using these methods: DispatcherTimer StartAfter(Action onComplete, TimeSpan duration) DispatcherTimer StartAfter(Action doWork,Action onComplete,TimeSpan duration) You can use this to perform some timed operation on the UI thread, as well as perform some operation in separate thread after some time. ParallelWork.StartAfter( () => { workStartedAt = DateTime.Now; Thread.Sleep(howLongWorkTakes); }, () => { workCompletedAt = DateTime.Now; }, waitDuration); Or, the fluent way: Start.Work(() => { workStartedAt = DateTime.Now; Thread.Sleep(howLongWorkTakes); }) .OnComplete(() => { workCompletedAt = DateTime.Now; }) .RunAfter(waitDuration);   There are several overloads of these functions to have a exception callback for handling exceptions or get progress update from background thread while work is in progress. For example, I use it in my PlantUmlEditor to perform background update of the application. // Check if there's a newer version of the app Start<bool>.Work(() => { return UpdateChecker.HasUpdate(Settings.Default.DownloadUrl); }) .OnComplete((hasUpdate) => { if (hasUpdate) { if (MessageBox.Show(Window.GetWindow(me), "There's a newer version available. Do you want to download and install?", "New version available", MessageBoxButton.YesNo, MessageBoxImage.Information) == MessageBoxResult.Yes) { ParallelWork.StartNow(() => { var tempPath = System.IO.Path.Combine( Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), Settings.Default.SetupExeName); UpdateChecker.DownloadLatestUpdate(Settings.Default.DownloadUrl, tempPath); }, () => { }, (x) => { MessageBox.Show(Window.GetWindow(me), "Download failed. When you run next time, it will try downloading again.", "Download failed", MessageBoxButton.OK, MessageBoxImage.Warning); }); } } }) .OnException((x) => { MessageBox.Show(Window.GetWindow(me), x.Message, "Download failed", MessageBoxButton.OK, MessageBoxImage.Exclamation); }); The above code shows you how to get exception callbacks on the UI thread so that you can take necessary actions on the UI. Moreover, it shows how you can chain two parallel works to happen one after another. Sometimes you want to do some parallel work when user does some activity on the UI. For example, you might want to save file in an editor while user is typing every 10 second. In such case, you need to make sure you don’t start another parallel work every 10 seconds while a work is already queued. You need to make sure you start a new work only when there’s no other background work going on. Here’s how you can do it: private void ContentEditor_TextChanged(object sender, EventArgs e) { if (!ParallelWork.IsAnyWorkRunning()) { ParallelWork.StartAfter(SaveAndRefreshDiagram, TimeSpan.FromSeconds(10)); } } If you want to shutdown your application and want to make sure no parallel work is going on, then you can call the StopAll() method. ParallelWork.StopAll(); If you want to wait for parallel works to complete without a timeout, then you can call the WaitForAllWork(TimeSpan timeout). It will block the current thread until the all parallel work completes or the timeout period elapses. result = ParallelWork.WaitForAllWork(TimeSpan.FromSeconds(1)); The result is true, if all parallel work completed. If it’s false, then the timeout period elapsed and all parallel work did not complete. For details how this library is built and how it works, please read the following codeproject article: ParallelWork: Feature rich multithreaded fluent task execution library for WPF http://www.codeproject.com/KB/WPF/parallelwork.aspx If you like the article, please vote for me.

  Read the article

• CLSF & CLK 2013 Trip Report by Jeff Liu

  - by jamesmorris

  This is a contributed post from Jeff Liu, lead XFS developer for the Oracle mainline Linux kernel team. Recently, I attended both the China Linux Storage and Filesystem workshop (CLSF), and the China Linux Kernel conference (CLK), which were held in Shanghai. Here are the highlights for both events. CLSF - 17th October XFS update (led by Jeff Liu) XFS keeps rapid progress with a lot of changes, especially focused on the infrastructure/performance improvements as well as  new feature development.  This can be reflected with a sample statistics among XFS/Ext4+JBD2/Btrfs via: # git diff --stat --minimal -C -M v3.7..v3.12-rc4 -- fs/xfs|fs/ext4+fs/jbd2|fs/btrfs XFS: 141 files changed, 27598 insertions(+), 19113 deletions(-) Ext4+JBD2: 39 files changed, 10487 insertions(+), 5454 deletions(-) Btrfs: 70 files changed, 19875 insertions(+), 8130 deletions(-) What made up those changes in XFS? Self-describing metadata(CRC32c). This is a new feature and it contributed about 70% code changes, it can be enabled via `mkfs.xfs -m crc=1 /dev/xxx` for v5 superblock. Transaction log space reservation improvements. With this change, we can calculate the log space reservation at mount time rather than runtime to reduce the the CPU overhead. User namespace support. So both XFS and USERNS can be enabled on kernel configuration begin from Linux 3.10. Thanks Dwight Engen's efforts for this thing. Split project/group quota inodes. Originally, project quota can not be enabled with group quota at the same time because they were share the same quota file inode, now it works but only for v5 super block. i.e, CRC enabled. CONFIG_XFS_WARN, an new lightweight runtime debugger which can be deployed in production environment. Readahead log object recovery, this change can speed up the log replay progress significantly. Speculative preallocation inode tracking, clearing and throttling. The main purpose is to deal with inodes with post-EOF space due to speculative preallocation, support improved quota management to free up a significant amount of unwritten space when at or near EDQUOT. It support backgroup scanning which occurs on a longish interval(5 mins by default, tunable), and on-demand scanning/trimming via ioctl(2). Bitter arguments ensued from this session, especially for the comparison between Ext4 and Btrfs in different areas, I have to spent a whole morning of the 1st day answering those questions. We basically agreed on XFS is the best choice in Linux nowadays because: Stable, XFS has a good record in stability in the past 10 years. Fengguang Wu who lead the 0-day kernel test project also said that he has observed less error than other filesystems in the past 1+ years, I own it to the XFS upstream code reviewer, they always performing serious code review as well as testing. Good performance for large/small files, XFS does not works very well for small files has already been an old story for years. Best choice (maybe) for distributed PB filesystems. e.g, Ceph recommends delopy OSD daemon on XFS because Ext4 has limited xattr size. Best choice for large storage (>16TB). Ext4 does not support a single file more than around 15.95TB. Scalability, any objection to XFS is best in this point? :) XFS is better to deal with transaction concurrency than Ext4, why? The maximum size of the log in XFS is 2038MB compare to 128MB in Ext4. Misc. Ext4 is widely used and it has been proved fast/stable in various loads and scenarios, XFS just need more customers, and Btrfs is still on the road to be a manhood. Ceph Introduction (Led by Li Wang) This a hot topic.  Li gave us a nice introduction about the design as well as their current works. Actually, Ceph client has been included in Linux kernel since 2.6.34 and supported by Openstack since Folsom but it seems that it has not yet been widely deployment in production environment. Their major work is focus on the inline data support to separate the metadata and data storage, reduce the file access time, i.e, a file access need communication twice, fetch the metadata from MDS and then get data from OSD, and also, the small file access is limited by the network latency. The solution is, for the small files they would like to store the data at metadata so that when accessing a small file, the metadata server can push both metadata and data to the client at the same time. In this way, they can reduce the overhead of calculating the data offset and save the communication to OSD. For this feature, they have only run some small scale testing but really saw noticeable improvements. Test environment: Intel 2 CPU 12 Core, 64GB RAM, Ubuntu 12.04, Ceph 0.56.6 with 200GB SATA disk, 15 OSD, 1 MDS, 1 MON. The sequence read performance for 1K size files improved about 50%. I have asked Li and Zheng Yan (the core developer of Ceph, who also worked on Btrfs) whether Ceph is really stable and can be deployed at production environment for large scale PB level storage, but they can not give a positive answer, looks Ceph even does not spread over Dreamhost (subject to confirmation). From Li, they only deployed Ceph for a small scale storage(32 nodes) although they'd like to try 6000 nodes in the future. Improve Linux swap for Flash storage (led by Shaohua Li) Because of high density, low power and low price, flash storage (SSD) is a good candidate to partially replace DRAM. A quick answer for this is using SSD as swap. But Linux swap is designed for slow hard disk storage, so there are a lot of challenges to efficiently use SSD for swap. SWAPOUT swap_map scan swap_map is the in-memory data structure to track swap disk usage, but it is a slow linear scan. It will become a bottleneck while finding many adjacent pages in the use of SSD. Shaohua Li have changed it to a cluster(128K) list, resulting in O(1) algorithm. However, this apporoach needs restrictive cluster alignment and only enabled for SSD. IO pattern In most cases, the swap io is in interleaved pattern because of mutiple reclaimers or a free cluster is shared by all reclaimers. Even though block layer can merge interleaved IO to some extent, but we cannot count on it completely. Hence the per-cpu cluster is added base on the previous change, it can help reclaimer do sequential IO and the block layer will be easier to merge IO. TLB flush: If we're reclaiming one active page, we should first move the page from active lru list to inactive lru list, and then reclaim the page from inactive lru to swap it out. During the process, we need to clear PTE twice: first is 'A'(ACCESS) bit, second is 'P'(PRESENT) bit. Processors need to send lots of ipi which make the TLB flush really expensive. Some works have been done to improve this, including rework smp_call_functiom_many() or remove the first TLB flush in x86, but there still have some arguments here and only parts of works have been pushed to mainline. SWAPIN: Page fault does iodepth=1 sync io, but it's a little waste if only issue a page size's IO. The obvious solution is doing swap readahead. But the current in-kernel swap readahead is arbitary(always 8 pages), and it always doesn't perform well for both random and sequential access workload. Shaohua introduced a new flag for madvise(MADV_WILLNEED) to do swap prefetch, so the changes happen in userspace API and leave the in-kernel readahead unchanged(but I think some improvement can also be done here). SWAP discard As we know, discard is important for SSD write throughout, but the current swap discard implementation is synchronous. He changed it to async discard which allow discard and write run in the same time. Meanwhile, the unit of discard is also optimized to cluster. Misc: lock contention For many concurrent swapout and swapin , the lock contention such as anon_vma or swap_lock is high, so he changed the swap_lock to a per-swap lock. But there still have some lock contention in very high speed SSD because of swapcache address_space lock. Zproject (led by Bob Liu) Bob gave us a very nice introduction about the current memory compression status. Now there are 3 projects(zswap/zram/zcache) which all aim at smooth swap IO storm and promote performance, but they all have their own pros and cons. ZSWAP It is implemented based on frontswap API and it uses a dynamic allocater named Zbud to allocate free pages. Zbud means pairs of zpages are "buddied" and it can only store at most two compressed pages in one page frame, so the max compress ratio is 50%. Each page frame is lru-linked and can do shink in memory pressure. If the compressed memory pool reach its limitation, shink or reclaim happens. It decompress the page frame into two new allocated pages and then write them to real swap device, but it can fail when allocating the two pages. ZRAM Acts as a compressed ramdisk and used as swap device, and it use zsmalloc as its allocator which has high density but may have fragmentation issues. Besides, page reclaim is hard since it will need more pages to uncompress and free just one page. ZRAM is preferred by embedded system which may not have any real swap device. Now both ZRAM and ZSWAP are in driver/staging tree, and in the mm community there are some disscussions of merging ZRAM into ZSWAP or viceversa, but no agreement yet. ZCACHE Handles file page compression but it is removed out of staging recently. From industry (led by Tang Jie, LSI) An LSI engineer introduced several new produces to us. The first is raid5/6 cards that it use full stripe writes to improve performance. The 2nd one he introduced is SandForce flash controller, who can understand data file types (data entropy) to reduce write amplification (WA) for nearly all writes. It's called DuraWrite and typical WA is 0.5. What's more, if enable its Dynamic Logical Capacity function module, the controller can do data compression which is transparent to upper layer. LSI testing shows that with this virtual capacity enables 1x TB drive can support up to 2x TB capacity, but the application must monitor free flash space to maintain optimal performance and to guard against free flash space exhaustion. He said the most useful application is for datebase. Another thing I think it's worth to mention is that a NV-DRAM memory in NMR/Raptor which is directly exposed to host system. Applications can directly access the NV-DRAM via a memory address - using standard system call mmap(). He said that it is very useful for database logging now. This kind of NVM produces are beginning to appear in recent years, and it is said that Samsung is building a research center in China for related produces. IMHO, NVM will bring an effect to current os layer especially on file system, e.g. its journaling may need to redesign to fully utilize these nonvolatile memory. OCFS2 (led by Canquan Shen) Without a doubt, HuaWei is the biggest contributor to OCFS2 in the past two years. They have posted 46 upstream patches and 39 patches have been merged. Their current project is based on 32/64 nodes cluster, but they also tried 128 nodes at the experimental stage. The major work they are working is to support ATS (atomic test and set), it can be works with DLM at the same time. Looks this idea is inspired by the vmware VMFS locking, i.e, http://blogs.vmware.com/vsphere/2012/05/vmfs-locking-uncovered.html CLK - 18th October 2013 Improving Linux Development with Better Tools (Andi Kleen) This talk focused on how to find/solve bugs along with the Linux complexity growing. Generally, we can do this with the following kind of tools: Static code checkers tools. e.g, sparse, smatch, coccinelle, clang checker, checkpatch, gcc -W/LTO, stanse. This can help check a lot of things, simple mistakes, complex problems, but the challenges are: some are very slow, false positives, may need a concentrated effort to get false positives down. Especially, no static checker I found can follow indirect calls (“OO in C”, common in kernel): struct foo_ops { int (*do_foo)(struct foo *obj); } foo->do_foo(foo); Dynamic runtime checkers, e.g, thread checkers, kmemcheck, lockdep. Ideally all kernel code would come with a test suite, then someone could run all the dynamic checkers. Fuzzers/test suites. e.g, Trinity is a great tool, it finds many bugs, but needs manual model for each syscall. Modern fuzzers around using automatic feedback, but notfor kernel yet: http://taviso.decsystem.org/making_software_dumber.pdf Debuggers/Tracers to understand code, e.g, ftrace, can dump on events/oops/custom triggers, but still too much overhead in many cases to run always during debug. Tools to read/understand source, e.g, grep/cscope work great for many cases, but do not understand indirect pointers (OO in C model used in kernel), give us all “do_foo” instances: struct foo_ops { int (*do_foo)(struct foo *obj); } = { .do_foo = my_foo }; foo>do_foo(foo); That would be great to have a cscope like tool that understands this based on types/initializers XFS: The High Performance Enterprise File System (Jeff Liu) [slides] I gave a talk for introducing the disk layout, unique features, as well as the recent changes.   The slides include some charts to reflect the performances between XFS/Btrfs/Ext4 for small files. About a dozen users raised their hands when I asking who has experienced with XFS. I remembered that when I asked the same question in LinuxCon/Japan, only 3 people raised their hands, but they are Chris Mason, Ric Wheeler, and another attendee. The attendee questions were mainly focused on stability, and comparison with other file systems. Linux Containers (Feng Gao) The speaker introduced us that the purpose for those kind of namespaces, include mount/UTS/IPC/Network/Pid/User, as well as the system API/ABI. For the userspace tools, He mainly focus on the Libvirt LXC rather than us(LXC). Libvirt LXC is another userspace container management tool, implemented as one type of libvirt driver, it can manage containers, create namespace, create private filesystem layout for container, Create devices for container and setup resources controller via cgroup. In this talk, Feng also mentioned another two possible new namespaces in the future, the 1st is the audit, but not sure if it should be assigned to user namespace or not. Another is about syslog, but the question is do we really need it? In-memory Compression (Bob Liu) Same as CLSF, a nice introduction that I have already mentioned above. Misc There were some other talks related to ACPI based memory hotplug, smart wake-affinity in scheduler etc., but my head is not big enough to record all those things. -- Jeff Liu

  Read the article

• What is SharePoint Out of the Box?

  - by Bil Simser

  It’s always fun in the blog-o-sphere and SharePoint bloggers always keep the pot boiling. Bjorn Furuknap recently posted a blog entry titled Why Out-of-the-Box Makes No Sense in SharePoint, quickly followed up by a rebuttal by Marc Anderson on his blog. Okay, now that we have all the players and the stage what’s the big deal? Bjorn started his post saying that you don’t use “out-of-the-box” (OOTB) SharePoint because it makes no sense. I have to disagree with his premise because what he calls OOTB is basically installing SharePoint and admiring it, but not using it. In his post he lays claim that modifying say the OOTB contacts list by removing (or I suppose adding) a column, now puts you in a situation where you’re no longer using the OOTB functionality. Really? Side note. Dear Internet, please stop comparing building software to building houses. Or comparing software architecture to building architecture. Or comparing web sites to making dinner. Are you trying to dumb down something so the general masses understand it? Comparing a technical skill to a construction operation isn’t the way to do this. Last time I checked, most people don’t know how to build houses and last time I checked people reading technical SharePoint blogs are generally technical people that understand the terms you use. Putting metaphors around software development to make it easy to understand is detrimental to the goal. </rant> Okay, where were we? Right, adding columns to lists means you are no longer using the OOTB functionality. Yeah, I still don’t get it. Another statement Bjorn makes is that using the OOTB functionality kills the flexibility SharePoint has in creating exactly what you want. IMHO this really flies in the absolute face of *where* SharePoint *really* shines. For the past year or so I’ve been leaning more and more towards OOTB solutions over custom development for the simple reason that its expensive to maintain systems and code and assets. SharePoint has enabled me to do this simply by providing the tools where I can give users what they need without cracking open up Visual Studio. This might be the fact that my day job is with a regulated company and there’s more scrutiny with spending money on anything new, but frankly that should be the position of any responsible developer, architect, manager, or PM. Do you really want to throw money away because some developer tells you that you need a custom web part when perhaps with some creative thinking or expectation setting with customers you can meet the need with what you already have. The way I read Bjorn’s terminology of “out-of-the-box” is install the software and tell people to go to a website and admire the OOTB system, but don’t change it! For those that know things like WordPress, DotNetNuke, SubText, Drupal or any of those content management/blogging systems, its akin to installing the software and setting up the “Hello World” blog post or page, then staring at it like it’s useful. “Yes, we are using WordPress!”. Then not adding a new post, creating a new category, or adding an About page. Perhaps I’m wrong in my interpretation. This leads us to what is OOTB SharePoint? To many people I’ve talked to the last few hours on twitter, email, etc. it is *not* just installing software but actually using it as it was fit for purpose. What’s the purpose of SharePoint then? It has many purposes, but using the OOTB templates Microsoft has given you the ability to collaborate on projects, author/share/publish documents, create pages, track items/contacts/tasks/etc. in a multi-user web based interface, and so on. Microsoft has pretty clear definitions of these different levels of SharePoint we’re talking about and I think it’s important for everyone to know what they are and what they mean. Personalization and Administration To me, this is the OOTB experience. You install the product and then are able to do things like create new lists, sites, edit and personalize pages, create new views, etc. Basically use the platform services available to you with Windows SharePoint Services (or SharePoint Foundation in 2010) to your full advantage. No code, no special tools needed, and very little user training required. Could you take someone who has never done anything in a website or piece of software and unleash them onto a site? Probably not. However I would argue that anyone who’s configured the Outlook reading layout or applied styles to a Word document probably won’t have too much difficulty in using SharePoint OUT OF THE BOX. Customization Here’s where things might get a bit murky but to me this is where you start looking at HTML/ASPX page code through SharePoint Designer, using jQuery scripts and plugging them into Web Part Pages via a Content Editor Web Part, and generally enhancing the site. The JavaScript debate might kick in here claiming it’s no different than C#, and frankly you can totally screw a site up with jQuery on a CEWP just as easily as you can with a C# delegate control deployed to the server file system. However (again, my blog, my opinion) the customization label comes in when I need to access the server (for example creating a custom theme) or have some kind of net-new element I add to the system that wasn’t there OOTB. It’s not content (like a new list or site), it’s code and does something functional. Development Here’s were the propeller hats come on and we’re talking algorithms and unit tests and compilers oh my. Software is deployed to the server, people are writing solutions after some kind of training (perhaps), there might be some specialized tools they use to craft and deploy the solutions, there’s the possibility of exceptions being thrown, etc. There are a lot of definitions here and just like customization it might get murky (do you let non-developers build solutions using development, i.e. jQuery/C#?). In my experience, it’s much more cost effective keeping solutions under the first two umbrellas than leaping into the third one. Arguably you could say that you can’t build useful solutions without *some* kind of code (even just some simple jQuery). I think you can get a *lot* of value just from using the OOTB experience and I don’t think you’re constraining your users that much. I’m not saying Marc or Bjorn are wrong. Like Obi-Wan stated, they’re both correct “from a certain point of view”. To me, SharePoint Out of the Box makes total sense and should not be dismissed. I just don’t agree with the premise that Bjorn is basing his statements on but that’s just my opinion and his is different and never the twain shall meet.

  Read the article

• Include weather information in ASP.Net site from weather.com services

  - by sreejukg

  In this article, I am going to demonstrate how you can use the XMLOAP services (referred as XOAP from here onwards) provided by weather.com to display the weather information in your website. The XOAP services are available to be used for free of charge, provided you are comply with requirements from weather.com. I am writing this article from a technical point of view. If you are planning to use weather.com XOAP services in your application, please refer to the terms and conditions from weather.com website. In order to start using the XOAP services, you need to sign up the XOAP datafeed. The signing process is simple, you simply browse the url http://www.weather.com/services/xmloap.html. The URL looks similar to the following. Click on the sign up button, you will reach the registration page. Here you need to specify the site name you need to use this feed for. The form looks similar to the following. Once you fill all the mandatory information, click on save and continue button. That’s it. The registration is over. You will receive an email that contains your partner id, license key and SDK. The SDK available in a zipped format, contains the terms of use and documentation about the services available. Other than this the SDK includes the logos and icons required to display the weather information. As per the SDK, currently there are 2 types of information available through XOAP. These services are Current Conditions for over 30,000 U.S. and over 7,900 international Location IDs Updated at least Hourly Five-Day Forecast (today + 4 additional forecast days in consecutive order beginning with tomorrow) for over 30,000 U.S. and over 7,900 international Location IDs Updated at least Three Times Daily The SDK provides detailed information about the fields included in response of each service. Additionally there is a refresh rate that you need to comply with. As per the SDK, the refresh rate means the following “Refresh Rate” shall mean the maximum frequency with which you may call the XML Feed for a given LocID requesting a data set for that LocID. During the time period in between refresh periods the data must be cached by you either in the memory on your servers or in Your Desktop Application. About the Services Weather.com will provide you with access to the XML Feed over the Internet through the hostname xoap.weather.com. The weather data from the XML feed must be requested for a specific location. So you need a location ID (LOC ID). The XML feed work with 2 types of location IDs. First one is with City Identifiers and second one is using 5 Digit US postal codes. If you do not know your location ID, don’t worry, there is a location id search service available for you to retrieve the location id from city name. Since I am a resident in the Kingdom of Bahrain, I am going to retrieve the weather information for Manama(the capital of Bahrain) . In order to get the location ID for Manama, type the following URL in your address bar. http://xoap.weather.com/search/search?where=manama I got the following XML output. <?xml version="1.0" encoding="UTF-8"?> <!-- This document is intended only for use by authorized licensees of The –> <!-- Weather Channel. Unauthorized use is prohibited. Copyright 1995-2011, –> <!-- The Weather Channel Interactive, Inc. All Rights Reserved. –> <search ver="3.0">       <loc id="BAXX0001" type="1">Al Manama, Bahrain</loc> </search> You can try this with any city name, if the city is available, it will return the location id, and otherwise, it will return nothing. In order to get the weather information, from XOAP,  you need to pass certain parameters to the XOAP service. A brief about the parameters are as follows. Please refer SDK for more details. Parameter name Possible Value cc Optional, if you include this, the current condition will be returned. Value can be anything, as it will be ignored e.g. cc=* dayf If you want the forecast for 5 days, specify dayf=5 This is optional iink Value should be XOAP par Your partner id. You can find this in your registration email from weather.com prod Value should be XOAP key The license key assigned to you. This will be available in the registration email unit s or m (standard or matric or you can think of Celsius/Fahrenheit) this is optional field, if not specified the unit will be standard(s) The URL host for the XOAP service is http://xoap.weather.com. So for my purpose, I need the following request to be made to access the XOAP services. http://xoap.weather.com/weather/local/BAXX0001?cc=*&link=xoap&prod=xoap&par=*********&key=************** (The ***** to be replaced with the corresponding alternatives) The response XML have a root element “weather”. Under the root element, it has the following sections <head> - the meta data information about the weather results returned. <loc> - the location data block that provides, the information about the location for which the wheather data is retrieved. <lnks> - the 4 promotional links you need to place along with the weather display. Additional to these 4 links, there should be another link with weather channel logo to the home page of weather.com. <cc> - the current condition data. This element will be there only if you specify the cc element in the request. <dayf> - the forcast data as you specified. This element will be there only if you specify the dayf in the request. In this walkthrough, I am going to capture the weather information for Manama (Location ID: BAXX0001). You need 2 applications to display weather information in your website. A Console application that retrieves data from the XMLOAP and store in the SQL Server database (or any data store as you prefer).This application will be scheduled to execute in every 25 minutes using windows task scheduler, so that we can comply with the refresh rate. A web application that display data from the SQL Server database Retrieve the Weather from XOAP I have created a console application named, Weather Service. I created a SQL server database, with the following columns. I named the table as tblweather. You are free to choose any name. Column name Description lastUpdated Datetime, this is the last time when the weather data is updated. This is the time of the service running TemparatureDateTime The date and time returned by XML feed Temparature The temperature returned by the XML feed. TemparatureUnit The unit of the temperature returned by the XML feed iconId The id of the icon to be used. Currently 48 icons from 0 to 47 are available. WeatherDescription The Weather Description Phrase returned by the feed. Link1url The url to the first promo link Link1Text The text for the first promo link Link2url The url to the second promo link Link2Text The text for the second promo link Link3url The url to the third promo link Link3Text The text for the third promo link Link4url The url to the fourth promo link Link4Text The text for the fourth promo link Every time when the service runs, the application will update the database columns from the XOAP data feed. When the application starts, It is going to get the data as XML from the url. This demonstration uses LINQ to extract the necessary data from the fetched XML. The following are the code segment for extracting data from the weather XML using LINQ. // first, create an instance of the XDocument class with the XOAP URL. replace **** with the corresponding values. XDocument weather = XDocument.Load("http://xoap.weather.com/weather/local/BAXX0001?cc=*&link=xoap&prod=xoap&par=***********&key=c*********"); // construct a query using LINQ var feedResult = from item in weather.Descendants() select new { unit = item.Element("head").Element("ut").Value, temp = item.Element("cc").Element("tmp").Value, tempDate = item.Element("cc").Element("lsup").Value, iconId = item.Element("cc").Element("icon").Value, description = item.Element("cc").Element("t").Value, links = from link in item.Elements("lnks").Elements("link") select new { url = link.Element("l").Value, text = link.Element("t").Value } }; // Load the root node to a variable, you may use foreach construct instead. var item1 = feedResult.First(); *If you want to learn more about LINQ and XML, read this nice blog from Scott GU. http://weblogs.asp.net/scottgu/archive/2007/08/07/using-linq-to-xml-and-how-to-build-a-custom-rss-feed-reader-with-it.aspx Now you have all the required values in item1. For e.g. if you want to get the temperature, use item1.temp; Now I just need to execute an SQL query against the database. See the connection part. using (SqlConnection conn = new SqlConnection(@"Data Source=sreeju\sqlexpress;Initial Catalog=Sample;Integrated Security=True")) { string strSql = @"update tblweather set lastupdated=getdate(), temparatureDateTime = @temparatureDateTime, temparature=@temparature, temparatureUnit=@temparatureUnit, iconId = @iconId, description=@description, link1url=@link1url, link1text=@link1text, link2url=@link2url, link2text=@link2text,link3url=@link3url, link3text=@link3text,link4url=@link4url, link4text=@link4text"; SqlCommand comm = new SqlCommand(strSql, conn); comm.Parameters.AddWithValue("temparatureDateTime", item1.tempDate); comm.Parameters.AddWithValue("temparature", item1.temp); comm.Parameters.AddWithValue("temparatureUnit", item1.unit); comm.Parameters.AddWithValue("description", item1.description); comm.Parameters.AddWithValue("iconId", item1.iconId); var lstLinks = item1.links; comm.Parameters.AddWithValue("link1url", lstLinks.ElementAt(0).url); comm.Parameters.AddWithValue("link1text", lstLinks.ElementAt(0).text); comm.Parameters.AddWithValue("link2url", lstLinks.ElementAt(1).url); comm.Parameters.AddWithValue("link2text", lstLinks.ElementAt(1).text); comm.Parameters.AddWithValue("link3url", lstLinks.ElementAt(2).url); comm.Parameters.AddWithValue("link3text", lstLinks.ElementAt(2).text); comm.Parameters.AddWithValue("link4url", lstLinks.ElementAt(3).url); comm.Parameters.AddWithValue("link4text", lstLinks.ElementAt(3).text); conn.Open(); comm.ExecuteNonQuery(); conn.Close(); Console.WriteLine("database updated"); } Now click ctrl + f5 to run the service. I got the following output Check your database and make sure, the data is updated with the latest information from the service. (Make sure you inserted one row in the database by entering some values before executing the service. Otherwise you need to modify your application code to count the rows and conditionally perform insert/update query) Display the Weather information in ASP.Net page Now you got all the data in the database. You just need to create a web application and display the data from the database. I created a new ASP.Net web application with a default.aspx page. In order to comply with the terms of weather.com, You need to use Weather.com logo along with the weather display. You can find the necessary logos to use under the folder “logos” in the SDK. Additionally copy any of the icon set from the folder “icons” to your web application. I used the 93x93 icon set. You are free to use any other sizes available. The design view of the page in VS2010 looks similar to the following. The page contains a heading, an image control (for displaying the weather icon), 2 label controls (for displaying temperature and weather description), 4 hyperlinks (for displaying the 4 promo links returned by the XOAP service) and weather.com logo with hyperlink to the weather.com home page. I am going to write code that will update the values of these controls from the values stored in the database by the service application as mentioned in the previous step. Go to the code behind file for the webpage, enter the following code under Page_Load event handler. using (SqlConnection conn = new SqlConnection(@"Data Source=sreeju\sqlexpress;Initial Catalog=Sample;Integrated Security=True")) { SqlCommand comm = new SqlCommand("select top 1 * from tblweather", conn); conn.Open(); SqlDataReader reader = comm.ExecuteReader(); if (reader.Read()) { lblTemparature.Text = reader["temparature"].ToString() + "&deg;" + reader["temparatureUnit"].ToString(); lblWeatherDescription.Text = reader["description"].ToString(); imgWeather.ImageUrl = "icons/" + reader["iconId"].ToString() + ".png"; lnk1.Text = reader["link1text"].ToString(); lnk1.NavigateUrl = reader["link1url"].ToString(); lnk2.Text = reader["link2text"].ToString(); lnk2.NavigateUrl = reader["link2url"].ToString(); lnk3.Text = reader["link3text"].ToString(); lnk3.NavigateUrl = reader["link3url"].ToString(); lnk4.Text = reader["link4text"].ToString(); lnk4.NavigateUrl = reader["link4url"].ToString(); } conn.Close(); } Press ctrl + f5 to run the page. You will see the following output. That’s it. You need to configure the console application to run every 25 minutes so that the database is updated. Also you can fetch the forecast information and store those in the database, and then retrieve it later in your web page. Since the data resides in your database, you have the full control over your display. You need to make sure your website comply with weather.com license requirements. If you want to get the source code of this walkthrough through the application, post your email address below. Hope you enjoy the reading.

  Read the article

• C#/.NET Fundamentals: Choosing the Right Collection Class

  - by James Michael Hare

  The .NET Base Class Library (BCL) has a wide array of collection classes at your disposal which make it easy to manage collections of objects. While it's great to have so many classes available, it can be daunting to choose the right collection to use for any given situation. As hard as it may be, choosing the right collection can be absolutely key to the performance and maintainability of your application! This post will look at breaking down any confusion between each collection and the situations in which they excel. We will be spending most of our time looking at the System.Collections.Generic namespace, which is the recommended set of collections. The Generic Collections: System.Collections.Generic namespace The generic collections were introduced in .NET 2.0 in the System.Collections.Generic namespace. This is the main body of collections you should tend to focus on first, as they will tend to suit 99% of your needs right up front. It is important to note that the generic collections are unsynchronized. This decision was made for performance reasons because depending on how you are using the collections its completely possible that synchronization may not be required or may be needed on a higher level than simple method-level synchronization. Furthermore, concurrent read access (all writes done at beginning and never again) is always safe, but for concurrent mixed access you should either synchronize the collection or use one of the concurrent collections. So let's look at each of the collections in turn and its various pros and cons, at the end we'll summarize with a table to help make it easier to compare and contrast the different collections. The Associative Collection Classes Associative collections store a value in the collection by providing a key that is used to add/remove/lookup the item. Hence, the container associates the value with the key. These collections are most useful when you need to lookup/manipulate a collection using a key value. For example, if you wanted to look up an order in a collection of orders by an order id, you might have an associative collection where they key is the order id and the value is the order. The Dictionary<TKey,TVale> is probably the most used associative container class. The Dictionary<TKey,TValue> is the fastest class for associative lookups/inserts/deletes because it uses a hash table under the covers. Because the keys are hashed, the key type should correctly implement GetHashCode() and Equals() appropriately or you should provide an external IEqualityComparer to the dictionary on construction. The insert/delete/lookup time of items in the dictionary is amortized constant time - O(1) - which means no matter how big the dictionary gets, the time it takes to find something remains relatively constant. This is highly desirable for high-speed lookups. The only downside is that the dictionary, by nature of using a hash table, is unordered, so you cannot easily traverse the items in a Dictionary in order. The SortedDictionary<TKey,TValue> is similar to the Dictionary<TKey,TValue> in usage but very different in implementation. The SortedDictionary<TKey,TValye> uses a binary tree under the covers to maintain the items in order by the key. As a consequence of sorting, the type used for the key must correctly implement IComparable<TKey> so that the keys can be correctly sorted. The sorted dictionary trades a little bit of lookup time for the ability to maintain the items in order, thus insert/delete/lookup times in a sorted dictionary are logarithmic - O(log n). Generally speaking, with logarithmic time, you can double the size of the collection and it only has to perform one extra comparison to find the item. Use the SortedDictionary<TKey,TValue> when you want fast lookups but also want to be able to maintain the collection in order by the key. The SortedList<TKey,TValue> is the other ordered associative container class in the generic containers. Once again SortedList<TKey,TValue>, like SortedDictionary<TKey,TValue>, uses a key to sort key-value pairs. Unlike SortedDictionary, however, items in a SortedList are stored as an ordered array of items. This means that insertions and deletions are linear - O(n) - because deleting or adding an item may involve shifting all items up or down in the list. Lookup time, however is O(log n) because the SortedList can use a binary search to find any item in the list by its key. So why would you ever want to do this? Well, the answer is that if you are going to load the SortedList up-front, the insertions will be slower, but because array indexing is faster than following object links, lookups are marginally faster than a SortedDictionary. Once again I'd use this in situations where you want fast lookups and want to maintain the collection in order by the key, and where insertions and deletions are rare. The Non-Associative Containers The other container classes are non-associative. They don't use keys to manipulate the collection but rely on the object itself being stored or some other means (such as index) to manipulate the collection. The List<T> is a basic contiguous storage container. Some people may call this a vector or dynamic array. Essentially it is an array of items that grow once its current capacity is exceeded. Because the items are stored contiguously as an array, you can access items in the List<T> by index very quickly. However inserting and removing in the beginning or middle of the List<T> are very costly because you must shift all the items up or down as you delete or insert respectively. However, adding and removing at the end of a List<T> is an amortized constant operation - O(1). Typically List<T> is the standard go-to collection when you don't have any other constraints, and typically we favor a List<T> even over arrays unless we are sure the size will remain absolutely fixed. The LinkedList<T> is a basic implementation of a doubly-linked list. This means that you can add or remove items in the middle of a linked list very quickly (because there's no items to move up or down in contiguous memory), but you also lose the ability to index items by position quickly. Most of the time we tend to favor List<T> over LinkedList<T> unless you are doing a lot of adding and removing from the collection, in which case a LinkedList<T> may make more sense. The HashSet<T> is an unordered collection of unique items. This means that the collection cannot have duplicates and no order is maintained. Logically, this is very similar to having a Dictionary<TKey,TValue> where the TKey and TValue both refer to the same object. This collection is very useful for maintaining a collection of items you wish to check membership against. For example, if you receive an order for a given vendor code, you may want to check to make sure the vendor code belongs to the set of vendor codes you handle. In these cases a HashSet<T> is useful for super-quick lookups where order is not important. Once again, like in Dictionary, the type T should have a valid implementation of GetHashCode() and Equals(), or you should provide an appropriate IEqualityComparer<T> to the HashSet<T> on construction. The SortedSet<T> is to HashSet<T> what the SortedDictionary<TKey,TValue> is to Dictionary<TKey,TValue>. That is, the SortedSet<T> is a binary tree where the key and value are the same object. This once again means that adding/removing/lookups are logarithmic - O(log n) - but you gain the ability to iterate over the items in order. For this collection to be effective, type T must implement IComparable<T> or you need to supply an external IComparer<T>. Finally, the Stack<T> and Queue<T> are two very specific collections that allow you to handle a sequential collection of objects in very specific ways. The Stack<T> is a last-in-first-out (LIFO) container where items are added and removed from the top of the stack. Typically this is useful in situations where you want to stack actions and then be able to undo those actions in reverse order as needed. The Queue<T> on the other hand is a first-in-first-out container which adds items at the end of the queue and removes items from the front. This is useful for situations where you need to process items in the order in which they came, such as a print spooler or waiting lines. So that's the basic collections. Let's summarize what we've learned in a quick reference table.  Collection Ordered? Contiguous Storage? Direct Access? Lookup Efficiency Manipulate Efficiency Notes Dictionary No Yes Via Key Key: O(1) O(1) Best for high performance lookups. SortedDictionary Yes No Via Key Key: O(log n) O(log n) Compromise of Dictionary speed and ordering, uses binary search tree. SortedList Yes Yes Via Key Key: O(log n) O(n) Very similar to SortedDictionary, except tree is implemented in an array, so has faster lookup on preloaded data, but slower loads. List No Yes Via Index Index: O(1) Value: O(n) O(n) Best for smaller lists where direct access required and no ordering. LinkedList No No No Value: O(n) O(1) Best for lists where inserting/deleting in middle is common and no direct access required. HashSet No Yes Via Key Key: O(1) O(1) Unique unordered collection, like a Dictionary except key and value are same object. SortedSet Yes No Via Key Key: O(log n) O(log n) Unique ordered collection, like SortedDictionary except key and value are same object. Stack No Yes Only Top Top: O(1) O(1)* Essentially same as List<T> except only process as LIFO Queue No Yes Only Front Front: O(1) O(1) Essentially same as List<T> except only process as FIFO   The Original Collections: System.Collections namespace The original collection classes are largely considered deprecated by developers and by Microsoft itself. In fact they indicate that for the most part you should always favor the generic or concurrent collections, and only use the original collections when you are dealing with legacy .NET code. Because these collections are out of vogue, let's just briefly mention the original collection and their generic equivalents: ArrayList A dynamic, contiguous collection of objects. Favor the generic collection List<T> instead. Hashtable Associative, unordered collection of key-value pairs of objects. Favor the generic collection Dictionary<TKey,TValue> instead. Queue First-in-first-out (FIFO) collection of objects. Favor the generic collection Queue<T> instead. SortedList Associative, ordered collection of key-value pairs of objects. Favor the generic collection SortedList<T> instead. Stack Last-in-first-out (LIFO) collection of objects. Favor the generic collection Stack<T> instead. In general, the older collections are non-type-safe and in some cases less performant than their generic counterparts. Once again, the only reason you should fall back on these older collections is for backward compatibility with legacy code and libraries only. The Concurrent Collections: System.Collections.Concurrent namespace The concurrent collections are new as of .NET 4.0 and are included in the System.Collections.Concurrent namespace. These collections are optimized for use in situations where multi-threaded read and write access of a collection is desired. The concurrent queue, stack, and dictionary work much as you'd expect. The bag and blocking collection are more unique. Below is the summary of each with a link to a blog post I did on each of them. ConcurrentQueue Thread-safe version of a queue (FIFO). For more information see: C#/.NET Little Wonders: The ConcurrentStack and ConcurrentQueue ConcurrentStack Thread-safe version of a stack (LIFO). For more information see: C#/.NET Little Wonders: The ConcurrentStack and ConcurrentQueue ConcurrentBag Thread-safe unordered collection of objects. Optimized for situations where a thread may be bother reader and writer. For more information see: C#/.NET Little Wonders: The ConcurrentBag and BlockingCollection ConcurrentDictionary Thread-safe version of a dictionary. Optimized for multiple readers (allows multiple readers under same lock). For more information see C#/.NET Little Wonders: The ConcurrentDictionary BlockingCollection Wrapper collection that implement producers & consumers paradigm. Readers can block until items are available to read. Writers can block until space is available to write (if bounded). For more information see C#/.NET Little Wonders: The ConcurrentBag and BlockingCollection Summary The .NET BCL has lots of collections built in to help you store and manipulate collections of data. Understanding how these collections work and knowing in which situations each container is best is one of the key skills necessary to build more performant code. Choosing the wrong collection for the job can make your code much slower or even harder to maintain if you choose one that doesn’t perform as well or otherwise doesn’t exactly fit the situation. Remember to avoid the original collections and stick with the generic collections.  If you need concurrent access, you can use the generic collections if the data is read-only, or consider the concurrent collections for mixed-access if you are running on .NET 4.0 or higher.   Tweet Technorati Tags: C#,.NET,Collecitons,Generic,Concurrent,Dictionary,List,Stack,Queue,SortedList,SortedDictionary,HashSet,SortedSet

  Read the article

• jQuery Templates - XHTML Validation

  - by hajan

  Many developers have already asked me about this. How to make XHTML valid the web page which uses jQuery Templates. Maybe you have already tried, and I don't know what are your results but here is my opinion regarding this. By default, Visual Studio.NET adds the xhtml1-transitional.dtd schema <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> So, if you try to validate your page which has jQuery Templates against this schema, your page won't be XHTML valid. Why? It's because when creating templates, we use HTML tags inside <script> ... </script> block. Yes, I know that the script block has type="text/html" but it's not supported in this schema, thus it's not valid. Let's try validate the following code Code <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" > <head>     <title>jQuery Templates :: XHTML Validation</title>     <script src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.min.js" type="text/javascript"></script>     <script src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js" type="text/javascript"></script>          <script language="javascript" type="text/javascript">         $(function () {             var attendees = [                 { Name: "Hajan", Surname: "Selmani", speaker: true, phones: [070555555, 071888999, 071222333] },                 { Name: "Denis", Surname: "Manski", phones: [070555555, 071222333] }             ];             $("#myTemplate").tmpl(attendees).appendTo("#attendeesList");         });     </script>     <script id="myTemplate" type="text/html">          <li>             ${Name} ${Surname}             {{if speaker}}                 (<font color="red">speaks</font>)             {{else}}                 (attendee)             {{/if}}         </li>     </script>      </head>     <body>     <ol id="attendeesList"></ol> </body> </html> To validate it, go to http://validator.w3.org/#validate_by_input and copy paste the code rendered on client-side browser (it’s almost the same, only the template is rendered inside OL so LI tags are created for each item). Press CHECK and you will get: Result: 1 Errors, 2 warning(s)  The error message says: Validation Output: 1 Error Line 21, Column 13: document type does not allow element "li" here <li> Yes, the <li> HTML element is not allowed inside the <script>, so how to make it valid? FIRST: Using <![CDATA][…]]> The first thing that came in my mind was the CDATA. So, by wrapping any HTML tag which is in script blog, inside <![CDATA[ ........ ]]> it will make our code valid. However, the problem is that the template won't render since the template tags {} cannot get evaluated if they are inside CDATA. Ok, lets try with another approach. SECOND: HTML5 validation Well, if we just remove the strikethrough part bellow of the !DOPCTYPE <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> our template is going to be checked as HTML5 and will be valid. Ok, there is another approach I've also tried: THIRD: Separate template to an external file We can separate the template to external file. I didn’t show how to do this previously, so here is the example. 1. Add HTML file with name Template.html in your ASPX website. 2. Place your defined template there without <script> tag Content inside Template.html <li>     ${Name} ${Surname}     {{if speaker}}         (<font color="red">speaks</font>)     {{else}}         (attendee)     {{/if}} </li> 3. Call the HTML file using $.get() jQuery ajax method and render the template with data using $.tmpl() function. $.get("/Templates/Template.html", function (template) {     $.tmpl(template, attendees).appendTo("#attendeesList"); }); So the complete code is: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" > <head>     <title>jQuery Templates :: XHTML Validation</title>     <script src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.min.js" type="text/javascript"></script>     <script src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js" type="text/javascript"></script>          <script language="javascript" type="text/javascript">         $(function () {             var attendees = [                 { Name: "Hajan", Surname: "Selmani", speaker: true, phones: [070555555, 071888999, 071222333] },                 { Name: "Denis", Surname: "Manski", phones: [070555555, 071222333] }             ];             $.get("/Templates/Template.html", function (template) {                 $.tmpl(template, attendees).appendTo("#attendeesList");             });         });     </script>      </head>     <body>     <ol id="attendeesList"></ol> </body> </html> This document was successfully checked as XHTML 1.0 Transitional! Result: Passed If you have any additional methods for XHTML validation, you can share it :). Thanks,Hajan

  Read the article

• Asserting with JustMock

  - by mehfuzh

  In this post, i will be digging in a bit deep on Mock.Assert. This is the continuation from previous post and covers up the ways you can use assert for your mock expectations. I have used another traditional sample of Talisker that has a warehouse [Collaborator] and an order class [SUT] that will call upon the warehouse to see the stock and fill it up with items. Our sample, interface of warehouse and order looks similar to : public interface IWarehouse {     bool HasInventory(string productName, int quantity);     void Remove(string productName, int quantity); }   public class Order {     public string ProductName { get; private set; }     public int Quantity { get; private set; }     public bool IsFilled { get; private set; }       public Order(string productName, int quantity)     {         this.ProductName = productName;         this.Quantity = quantity;     }       public void Fill(IWarehouse warehouse)     {         if (warehouse.HasInventory(ProductName, Quantity))         {             warehouse.Remove(ProductName, Quantity);             IsFilled = true;         }     }   }   Our first example deals with mock object assertion [my take] / assert all scenario. This will only act on the setups that has this “MustBeCalled” flag associated. To be more specific , let first consider the following test code:    var order = new Order(TALISKER, 0);    var wareHouse = Mock.Create<IWarehouse>();      Mock.Arrange(() => wareHouse.HasInventory(Arg.Any<string>(), 0)).Returns(true).MustBeCalled();    Mock.Arrange(() => wareHouse.Remove(Arg.Any<string>(), 0)).Throws(new InvalidOperationException()).MustBeCalled();    Mock.Arrange(() => wareHouse.Remove(Arg.Any<string>(), 100)).Throws(new InvalidOperationException());      //exercise    Assert.Throws<InvalidOperationException>(() => order.Fill(wareHouse));    // it will assert first and second setup.    Mock.Assert(wareHouse); Here, we have created the order object, created the mock of IWarehouse , then I setup our HasInventory and Remove calls of IWarehouse with my expected, which is called by the order.Fill internally. Now both of these setups are marked as “MustBeCalled”. There is one additional IWarehouse.Remove that is invalid and is not marked.   On line 9 ,  as we do order.Fill , the first and second setups will be invoked internally where the third one is left  un-invoked. Here, Mock.Assert will pass successfully as  both of the required ones are called as expected. But, if we marked the third one as must then it would fail with an  proper exception. Here, we can also see that I have used the same call for two different setups, this feature is called sequential mocking and will be covered later on. Moving forward, let’s say, we don’t want this must call, when we want to do it specifically with lamda. For that let’s consider the following code: //setup - data var order = new Order(TALISKER, 50); var wareHouse = Mock.Create<IWarehouse>();   Mock.Arrange(() => wareHouse.HasInventory(TALISKER, 50)).Returns(true);   //exercise order.Fill(wareHouse);   //verify state Assert.True(order.IsFilled); //verify interaction Mock.Assert(()=> wareHouse.HasInventory(TALISKER, 50));   Here, the snippet shows a case for successful order, i haven’t used “MustBeCalled” rather i used lamda specifically to assert the call that I have made, which is more justified for the cases where we exactly know the user code will behave. But, here goes a question that how we are going assert a mock call if we don’t know what item a user code may request for. In that case, we can combine the matchers with our assert calls like we do it for arrange: //setup - data  var order = new Order(TALISKER, 50);  var wareHouse = Mock.Create<IWarehouse>();    Mock.Arrange(() => wareHouse.HasInventory(TALISKER, Arg.Matches<int>( x => x <= 50))).Returns(true);    //exercise  order.Fill(wareHouse);    //verify state  Assert.True(order.IsFilled);    //verify interaction  Mock.Assert(() => wareHouse.HasInventory(Arg.Any<string>(), Arg.Matches<int>(x => x <= 50)));   Here, i have asserted a mock call for which i don’t know the item name,  but i know that number of items that user will request is less than 50.  This kind of expression based assertion is now possible with JustMock. We can extent this sample for properties as well, which will be covered shortly [in other posts]. In addition to just simple assertion, we can also use filters to limit to times a call has occurred or if ever occurred. Like for the first test code, we have one setup that is never invoked. For such, it is always valid to use the following assert call: Mock.Assert(() => wareHouse.Remove(Arg.Any<string>(), 100), Occurs.Never()); Or ,for warehouse.HasInventory we can do the following: Mock.Assert(() => wareHouse.HasInventory(Arg.Any<string>(), 0), Occurs.Once()); Or,  to be more specific, it’s even better with: Mock.Assert(() => wareHouse.HasInventory(Arg.Any<string>(), 0), Occurs.Exactly(1));   There are other filters  that you can apply here using AtMost, AtLeast and AtLeastOnce but I left those to the readers. You can try the above sample that is provided in the examples shipped with JustMock.Please, do check it out and feel free to ping me for any issues.   Enjoy!!

  Read the article

• SQLAuthority News – Social Media Series – YouTube and Movies

  - by pinaldave

  Pinal Dave on Youtube! Some people might not know it, but YouTube is actually more than a place to watch funny cat videos and people singing their favorite pop songs – it’s actually a social media site.  When you are a member of YouTube you can follow people who regularly post videos, post video responses of your own, and even gain a following for your own videos.  I myself was not aware of YouTube’s potential until recently, when I started to make SQL Server in Sixty Seconds videos. YouTube is very different than other types of social media, and a big factor is that anyone can look at videos without being a member.  Unlike other social media sites, like Twitter and Facebook, you have to have an account in order to participate.  But on YouTube you are even more anonymous.  To make and post videos you need an account, but anyone who comes to the site can look at what you’ve made without signing in or leaving any trace of having seen your material.  This makes YouTube very anonymous and hard to track. However, we should not overlook the power of video on the internet.  Over the past few months I have been making SQL Server in Sixty Second videos and have come to love it.  It is very exciting to be able to talk about a subject that mostly I write about, and for many people video is far more accessible and easy to understand.   I have really enjoyed diving into something new, and would love to have more people check out these videos and give me feedback.  You can find me at www.youtube.com/user/pinaldave. I am very excited with all the possibilities on YouTube and it might just be the technology evangelist in me, but I would love for other people to discover how fun and exciting this site can be, too.  Don’t think of it as just a place to find funny videos and waste a few minutes of your time, think of it as a place to learn and interact with interesting people.  Come watch a few of my videos, while you’re there.  Remember, everything is free and there are no contracts to sign, but I hope that you get as excited as I am and join up.  We need more people creating good content on this site! Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology Tagged: Social Media

  Read the article

• MSCC: Scripting - Administrator's­ toolbox of magic...

  Finally, we made it to have our April meetup - in May. The most obvious explanation is the increased amount of open source and IT activities that either the MSCC, the Linux User Group of Mauritius (LUGM), or the University of Mauritius Student's Computer Club is organising. It's absolutely incredible to see the recent hype of events here on the island. And I'm loving it! Unfortunately, we also had to deal with arranging for a location this time. It was kind of an odyssey as my requests (and phone calls) haven't been answered, even though I tried it several times - well, kind of disappointing and I have to look into that for future gatherings. In my opinion, it is essential that two parameters of a community meeting are fixed as early as possible: Location, and Date and time You can't just change one or both on the very last minute. Well, this time we had to do it due to unforeseen reasons, and I apologise to any MSCC member which couldn't make it to our April meetup. Okay, lesson learned but now back to the actual meetup report ... Shortly after the meeting I placed the following statement as my first impression: "Spontaneous and improvised :) No, seriously, Ish and Dan had well prepared presentations on shell scripting, mainly focused towards Bourne Again Shell (bash), and the pros and cons of scripting versus actually writing something in a decent programming language. I thought that I could cut myself out of the equation but the demand for information about PowerShell was higher than expected..." Well, it turned out that the interest in Windows PowerShell was high, as I even got a couple of questions on it via social media networks during the evening. I also like to mention that the number of attendees went back to what I would call a "standard" number of participation. This time there were 12 craftsmen, but again a good number of First Timers. Reactions of other attendees Here are some impressions and feedback from our participants: "Enjoyed the bash and powershell (linux / windows) presentations ..." -- Nadim on event comments "He [Daniel] also showed us some syntax loopholes in Bash that could leave someone with bad code." -- Ish on MSCC – Let's talk about Scripting   Glad to see a couple of first time attendees, especially students from the university itself. Some details on the presentations MSCC: First time visit at the University of Mauritius - Phase II Engineering Tower, room 2.9 Gimme some love ... bash and other shells Ish gave a great introduction into shell scripting as he spoke about existing shell environments and a little bit about their history. Furthermore, he talked about various built-in commands, the use of coreutils, the ability to daisy-chain multiple commands using pipes, the importance of the standard I/O streams and their file descriptors in advanced scripting techniques. Combined with a couple of sample statements in the Linux terminal on Ubuntu 14.04 machine it was a solid presentation. Have a closer look at his slides - published on his blog on MSCC – Let's talk about Scripting. Oddities of scripting After the brief introduction into bash it was Daniel's turn to highlight a good number of oddities when working with shell scripts. First of all, it should be clear that scripting is not supposed for any kind of implementations in terms of software but simply to automate administrative procedures and to simplify routine jobs on a system. One of the cool oddities that he mentioned is that everything (!) in a shell is represented by strings; there are no other types like integer, float, date-time, etc. that you'd like to use in a full-fledged programming language. Let's have a look at his sample:  more to come... What's the output? As a conclusion, Daniel suggests that shell scripting should be limited but not restricted to automatic repetitive command stacks and batch jobs, startup wrapper for applications in order to set up the execution environment, and other not too sophisticated jobs. But as soon as it might involve a little bit more logic or you might rely on performance it's better to write an application in Ruby, Python, or Perl (among others of course). This is also enables the possibility to test your code properly. MSCC: Ish talking about Bourne Again Shell (bash) and shell scripting to automate regular tasks MSCC: Daniel gives an overview about the pros and cons of shell scripting versus programming MSCC: PowerShell as your scripting solution on Windows operating systems The path of the Enlightened is long ... and tough. Honestly, even though PowerShell was mentioned without any further details on the meetup's agenda, I didn't expect that there would be demand to give a presentation on Microsoft PowerShell after all. I already took this topic out of the announcement but the audience wanted to have some information. Okay, then let's see what I could do - improvised style. While my machine booted and got hooked up to the projector, I started to talk about the beginnings of PowerShell from back in 2006, and its predecessors MS DOS and Command Prompt. A throwback in history... always good for young people. As usual, Microsoft didn't get it at that time. Instead of listening to their client's needs and demands they ignored the feasibility to administrate Windows server farms without any UI tools. PowerShell is actually a result of this, and seeing that shell scripting is a common, reliable and fast way in an administrator's toolbox for decades, Microsoft had to adapt from their Microsoft Management Console (MMC) to a broader approach. It's not like shell scripting was something new; it is in daily use by alternative operating systems like AIX, HP UX, Solaris, and last but not least Linux. Most interestingly, Microsoft is very good at renovating existing architectures, and over the years PowerShell not only replaced their own combination of Command Prompt and Scripting Hosts (VBScript and CScript) but really turned into a challenging competitor on the market. The shell is easy to extend with cmdlets, and open to other Microsoft products like SQL Server, SharePoint, as well as Third-party software applications. Similar to MMC PowerShell also offers the ability to administer other machine remotely - only without a graphical user interface and therefore it's easier to automate and schedule regular tasks. Following is a sample of a PowerShell script file (extension .ps1): $strComputer = "." $colItems = get-wmiobject -class Win32_BIOS -namespace root\CIMV2 -comp $strComputer foreach ($objItem in $colItems) {write-host "BIOS Characteristics: " $objItem.BiosCharacteristicswrite-host "BIOS Version: " $objItem.BIOSVersionwrite-host "Build Number: " $objItem.BuildNumberwrite-host "Caption: " $objItem.Captionwrite-host "Code Set: " $objItem.CodeSetwrite-host "Current Language: " $objItem.CurrentLanguagewrite-host "Description: " $objItem.Descriptionwrite-host "Identification Code: " $objItem.IdentificationCodewrite-host "Installable Languages: " $objItem.InstallableLanguageswrite-host "Installation Date: " $objItem.InstallDatewrite-host "Language Edition: " $objItem.LanguageEditionwrite-host "List Of Languages: " $objItem.ListOfLanguageswrite-host "Manufacturer: " $objItem.Manufacturerwrite-host "Name: " $objItem.Namewrite-host "Other Target Operating System: " $objItem.OtherTargetOSwrite-host "Primary BIOS: " $objItem.PrimaryBIOSwrite-host "Release Date: " $objItem.ReleaseDatewrite-host "Serial Number: " $objItem.SerialNumberwrite-host "SMBIOS BIOS Version: " $objItem.SMBIOSBIOSVersionwrite-host "SMBIOS Major Version: " $objItem.SMBIOSMajorVersionwrite-host "SMBIOS Minor Version: " $objItem.SMBIOSMinorVersionwrite-host "SMBIOS Present: " $objItem.SMBIOSPresentwrite-host "Software Element ID: " $objItem.SoftwareElementIDwrite-host "Software Element State: " $objItem.SoftwareElementStatewrite-host "Status: " $objItem.Statuswrite-host "Target Operating System: " $objItem.TargetOperatingSystemwrite-host "Version: " $objItem.Versionwrite-host} Which gives you information about your BIOS and Windows OS. Then change the computer name to another one on your network (NetBIOS based) and run the script again. There lots of samples and tutorials at the Microsoft Script Center, and I would advise you to pay a visit over there if you are more interested in PowerShell. The Script Center provides the download links, too. Upcoming Events What are the upcoming events here in Mauritius? So far, we have the following ones (incomplete list as usual) in chronological order: Hacking Defence (14. May 2014) WebCup Maurice (7. & 8. June 2014) Developers Conference (TBA ~ July 2014) Linuxfest 2014 (TBA ~ November 2014) Hopefully, there will be more announcements during the next couple of weeks and months. If you know about any other event, like a bootcamp, a code challenge or hackathon here in Mauritius, please drop me a note in the comment section below this article. Thanks! My resume of the day Spontaneous and improvised :) The new location at the University of Mauritius turned out very well, there is plenty of space, and it could be a good choice for future meetings. Especially, having the ability to get more and more students into our IT community sounds like a great opportunity. Later during the day, I got some promising mails from Nadim regarding future sessions at the local branch of the Middlesex University. Well, we will see in the future... But for now this will be on hold until approximately October when students resume their regular studies. Anyway, it was a good experience at the university, and thanks again to the UoM Student's Computer Club that made the necessary arrangements for the MSCC!

  Read the article

• Handling HTTP 404 Error in ASP.NET Web API

  - by imran_ku07

          Introduction:                     Building modern HTTP/RESTful/RPC services has become very easy with the new ASP.NET Web API framework. Using ASP.NET Web API framework, you can create HTTP services which can be accessed from browsers, machines, mobile devices and other clients. Developing HTTP services is now become more easy for ASP.NET MVC developer becasue ASP.NET Web API is now included in ASP.NET MVC. In addition to developing HTTP services, it is also important to return meaningful response to client if a resource(uri) not found(HTTP 404) for a reason(for example, mistyped resource uri). It is also important to make this response centralized so you can configure all of 'HTTP 404 Not Found' resource at one place. In this article, I will show you how to handle 'HTTP 404 Not Found' at one place.         Description:                     Let's say that you are developing a HTTP RESTful application using ASP.NET Web API framework. In this application you need to handle HTTP 404 errors in a centralized location. From ASP.NET Web API point of you, you need to handle these situations, No route matched. Route is matched but no {controller} has been found on route. No type with {controller} name has been found. No matching action method found in the selected controller due to no action method start with the request HTTP method verb or no action method with IActionHttpMethodProviderRoute implemented attribute found or no method with {action} name found or no method with the matching {action} name found.                                          Now, let create a ErrorController with Handle404 action method. This action method will be used in all of the above cases for sending HTTP 404 response message to the client.  public class ErrorController : ApiController { [HttpGet, HttpPost, HttpPut, HttpDelete, HttpHead, HttpOptions, AcceptVerbs("PATCH")] public HttpResponseMessage Handle404() { var responseMessage = new HttpResponseMessage(HttpStatusCode.NotFound); responseMessage.ReasonPhrase = "The requested resource is not found"; return responseMessage; } }                     You can easily change the above action method to send some other specific HTTP 404 error response. If a client of your HTTP service send a request to a resource(uri) and no route matched with this uri on server then you can route the request to the above Handle404 method using a custom route. Put this route at the very bottom of route configuration,  routes.MapHttpRoute( name: "Error404", routeTemplate: "{*url}", defaults: new { controller = "Error", action = "Handle404" } );                     Now you need handle the case when there is no {controller} in the matching route or when there is no type with {controller} name found. You can easily handle this case and route the request to the above Handle404 method using a custom IHttpControllerSelector. Here is the definition of a custom IHttpControllerSelector, public class HttpNotFoundAwareDefaultHttpControllerSelector : DefaultHttpControllerSelector { public HttpNotFoundAwareDefaultHttpControllerSelector(HttpConfiguration configuration) : base(configuration) { } public override HttpControllerDescriptor SelectController(HttpRequestMessage request) { HttpControllerDescriptor decriptor = null; try { decriptor = base.SelectController(request); } catch (HttpResponseException ex) { var code = ex.Response.StatusCode; if (code != HttpStatusCode.NotFound) throw; var routeValues = request.GetRouteData().Values; routeValues["controller"] = "Error"; routeValues["action"] = "Handle404"; decriptor = base.SelectController(request); } return decriptor; } }                     Next, it is also required to pass the request to the above Handle404 method if no matching action method found in the selected controller due to the reason discussed above. This situation can also be easily handled through a custom IHttpActionSelector. Here is the source of custom IHttpActionSelector,  public class HttpNotFoundAwareControllerActionSelector : ApiControllerActionSelector { public HttpNotFoundAwareControllerActionSelector() { } public override HttpActionDescriptor SelectAction(HttpControllerContext controllerContext) { HttpActionDescriptor decriptor = null; try { decriptor = base.SelectAction(controllerContext); } catch (HttpResponseException ex) { var code = ex.Response.StatusCode; if (code != HttpStatusCode.NotFound && code != HttpStatusCode.MethodNotAllowed) throw; var routeData = controllerContext.RouteData; routeData.Values["action"] = "Handle404"; IHttpController httpController = new ErrorController(); controllerContext.Controller = httpController; controllerContext.ControllerDescriptor = new HttpControllerDescriptor(controllerContext.Configuration, "Error", httpController.GetType()); decriptor = base.SelectAction(controllerContext); } return decriptor; } }                     Finally, we need to register the custom IHttpControllerSelector and IHttpActionSelector. Open global.asax.cs file and add these lines,  configuration.Services.Replace(typeof(IHttpControllerSelector), new HttpNotFoundAwareDefaultHttpControllerSelector(configuration)); configuration.Services.Replace(typeof(IHttpActionSelector), new HttpNotFoundAwareControllerActionSelector());         Summary:                       In addition to building an application for HTTP services, it is also important to send meaningful centralized information in response when something goes wrong, for example 'HTTP 404 Not Found' error.  In this article, I showed you how to handle 'HTTP 404 Not Found' error in a centralized location. Hopefully you will enjoy this article too.

  Read the article

• AdvancedFormatProvider: Making string.format do more

  - by plblum

  When I have an integer that I want to format within the String.Format() and ToString(format) methods, I’m always forgetting the format symbol to use with it. That’s probably because its not very intuitive. Use {0:N0} if you want it with group (thousands) separators. text = String.Format("{0:N0}", 1000); // returns "1,000"   int value1 = 1000; text = value1.ToString("N0"); Use {0:D} or {0:G} if you want it without group separators. text = String.Format("{0:D}", 1000); // returns "1000"   int value2 = 1000; text2 = value2.ToString("D"); The {0:D} is especially confusing because Microsoft gives the token the name “Decimal”. I thought it reasonable to have a new format symbol for String.Format, "I" for integer, and the ability to tell it whether it shows the group separators. Along the same lines, why not expand the format symbols for currency ({0:C}) and percent ({0:P}) to let you omit the currency or percent symbol, omit the group separator, and even to drop the decimal part when the value is equal to the whole number? My solution is an open source project called AdvancedFormatProvider, a group of classes that provide the new format symbols, continue to support the rest of the native symbols and makes it easy to plug in additional format symbols. Please visit https://github.com/plblum/AdvancedFormatProvider to learn about it in detail and explore how its implemented. The rest of this post will explore some of the concepts it takes to expand String.Format() and ToString(format). AdvancedFormatProvider benefits: Supports {0:I} token for integers. It offers the {0:I-,} option to omit the group separator. Supports {0:C} token with several options. {0:C-$} omits the currency symbol. {0:C-,} omits group separators, and {0:C-0} hides the decimal part when the value would show “.00”. For example, 1000.0 becomes “$1000” while 1000.12 becomes “$1000.12”. Supports {0:P} token with several options. {0:P-%} omits the percent symbol. {0:P-,} omits group separators, and {0:P-0} hides the decimal part when the value would show “.00”. For example, 1 becomes “100 %” while 1.1223 becomes “112.23 %”. Provides a plug in framework that lets you create new formatters to handle specific format symbols. You register them globally so you can just pass the AdvancedFormatProvider object into String.Format and ToString(format) without having to figure out which plug ins to add. text = String.Format(AdvancedFormatProvider.Current, "{0:I}", 1000); // returns "1,000" text2 = String.Format(AdvancedFormatProvider.Current, "{0:I-,}", 1000); // returns "1000" text3 = String.Format(AdvancedFormatProvider.Current, "{0:C-$-,}", 1000.0); // returns "1000.00" The IFormatProvider parameter Microsoft has made String.Format() and ToString(format) format expandable. They each take an additional parameter that takes an object that implements System.IFormatProvider. This interface has a single member, the GetFormat() method, which returns an object that knows how to convert the format symbol and value into the desired string. There are already a number of web-based resources to teach you about IFormatProvider and the companion interface ICustomFormatter. I’ll defer to them if you want to dig more into the topic. The only thing I want to point out is what I think are implementation considerations. Why GetFormat() always tests for ICustomFormatter When you see examples of implementing IFormatProviders, the GetFormat() method always tests the parameter against the ICustomFormatter type. Why is that? public object GetFormat(Type formatType) { if (formatType == typeof(ICustomFormatter)) return this; else return null; } The value of formatType is already predetermined by the .net framework. String.Format() uses the StringBuilder.AppendFormat() method to parse the string, extracting the tokens and calling GetFormat() with the ICustomFormatter type. (The .net framework also calls GetFormat() with the types of System.Globalization.NumberFormatInfo and System.Globalization.DateTimeFormatInfo but these are exclusive to how the System.Globalization.CultureInfo class handles its implementation of IFormatProvider.) Your code replaces instead of expands I would have expected the caller to pass in the format string to GetFormat() to allow your code to determine if it handles the request. My vision would be to return null when the format string is not supported. The caller would iterate through IFormatProviders until it finds one that handles the format string. Unfortunatley that is not the case. The reason you write GetFormat() as above is because the caller is expecting an object that handles all formatting cases. You are effectively supposed to write enough code in your formatter to handle your new cases and call .net functions (like String.Format() and ToString(format)) to handle the original cases. Its not hard to support the native functions from within your ICustomFormatter.Format function. Just test the format string to see if it applies to you. If not, call String.Format() with a token using the format passed in. public string Format(string format, object arg, IFormatProvider formatProvider) { if (format.StartsWith("I")) { // handle "I" formatter } else return String.Format(formatProvider, "{0:" + format + "}", arg); } Formatters are only used by explicit request Each time you write a custom formatter (implementer of ICustomFormatter), it is not used unless you explicitly passed an IFormatProvider object that supports your formatter into String.Format() or ToString(). This has several disadvantages: Suppose you have several ICustomFormatters. In order to have all available to String.Format() and ToString(format), you have to merge their code and create an IFormatProvider to return an instance of your new class. You have to remember to utilize the IFormatProvider parameter. Its easy to overlook, especially when you have existing code that calls String.Format() without using it. Some APIs may call String.Format() themselves. If those APIs do not offer an IFormatProvider parameter, your ICustomFormatter will not be available to them. The AdvancedFormatProvider solves the first two of these problems by providing a plug-in architecture.

  Read the article

• WP7 Tips–Part I– Media File Coding Techniques to help pass the Windows Phone 7 Marketplace Certification Requirements

  - by seaniannuzzi

  Overview Developing an application that plays media files on a Windows Phone 7 Device seems fairly straight forward.  However, what can make this a bit frustrating are the necessary requirements in order to pass the WP7 marketplace requirements so that your application can be published.  If you are new to this development, be aware of these common challenges that are likely to be made.  Below are some techniques and recommendations on how optimize your application to handle playing MP3 and/or WMA files that needs to adhere to the marketplace requirements.   Windows Phone 7 Certification Requirements Windows Phone 7 Developers Blog   Some common challenges are: Not prompting the user if another media file is playing in the background before playing your media file Not allowing the user to control the volume Not allowing the user to mute the sound Not allowing the media to be interrupted by a phone call  To keep this as simple as possible I am only going to focus on what “not to do” and what “to do” in order to implement a simple media solution. Things you will need or may be useful to you before you begin: Visual Studio 2010 Visual Studio 2010 Feature Packs Windows Phone 7 Developer Tools Visual Studio 2010 Express for Windows Phone Windows Phone Emulator Resources Silverlight 4 Tools For Visual Studio XNA Game Studio 4.0 Microsoft Expression Blend for Windows Phone Note: Please keep in mind you do not need all of these downloaded and installed, it is just easier to have all that you need now rather than add them on later.   Objective Summary Create a Windows Phone 7 – Windows Media Sample Application.  The application will implement many of the required features in order to pass the WP7 marketplace certification requirements in order to publish an application to WP7’s marketplace. (Disclaimer: I am not trying to indicate that this application will always pass as the requirements may change or be updated)   Step 1: – Create a New Windows Phone 7 Project   Step 2: – Update the Title and Application Name of your WP7 Application For this example I changed: the Title to: “DOTNETNUZZI WP7 MEDIA SAMPLE - v1.00” and the Page Title to:  “media magic”. Note: I also updated the background.   Step 3: – XAML - Media Element Preparation and Best Practice Before we begin the next step I just wanted to point out a few things that you should not do as a best practice when developing an application for WP7 that is playing music.  Please keep in mind that these requirements are not the same if you are playing Sound Effects and are geared towards playing media in the background.   If you have coded this – be prepared to change it:   To avoid a failure from the market place remove all of your media source elements from your XAML or simply create them dynamically.  To keep this simple we will remove the source and set the AutoPlay property to false to ensure that there are no media elements are active when the application is started. Proper example of the media element with No Source:   Some Additional Settings - Add XAML Support for a Mute Button   Step 4: – Boolean to handle toggle of Mute Feature Step 5: – Add Event Handler for Main Page Load   Step 6: – Add Reference to the XNA Framework   Step 7: – Add two Using Statements to Resolve the Namespace of Media and the Application Bar using Microsoft.Xna.Framework.Media; using Microsoft.Phone.Shell;   Step 8: – Add the Method to Check the Media State as Shown Below   Step 9: – Add Code to Mute the Media File Step 10: – Add Code to Play the Media File //if the state of the media has been checked you are good to go. media_sample.Play(); Note: If we tried to perform this operation at this point you will receive the following error: System.InvalidOperationException was unhandled Message=FrameworkDispatcher.Update has not been called. Regular FrameworkDispatcher.Update calls are necessary for fire and forget sound effects and framework events to function correctly. See http://go.microsoft.com/fwlink/?LinkId=193853 for details. StackTrace:        at Microsoft.Xna.Framework.FrameworkDispatcher.AddNewPendingCall(ManagedCallType callType, UInt32 arg)        at Microsoft.Xna.Framework.UserAsyncDispatcher.HandleManagedCallback(ManagedCallType managedCallType, UInt32 managedCallArgs) at Microsoft.Xna.Framework.UserAsyncDispatcher.AsyncDispatcherThreadFunction()            It is not recommended that you just add the FrameworkDispatcher.Update(); call before playing the media file. It is recommended that you implement the following class to your solution and implement this class in the app.xaml.cs file.   Step 11: – Add FrameworkDispatcher Features I recommend creating a class named XNAAsyncDispatcher and adding the following code:   After you have added the code accordingly, you can now implement this into your app.xaml.cs file as highlighted below.   Note:  If you application sound file is not playing make sure you have the proper “Build Action” set such as Content.   Running the Sample Now that we have some of the foundation created you should be able to run the application successfully.  When the application launches your sound options should be set accordingly when the “checkMediaState” method is called.  As a result the application will properly setup the media options and/or alert the user accordinglyper the certification requirements.  In addition, the sample also shows a quick way to mute the sound in your application by simply removing the URI source of the media file.  If everything successfully compiled the application should look similar to below.                 <sound playing>   Summary At this point we have a fully functional application that provides techniques on how to avoid some common challenges when working with media files and developing applications for Windows Phone 7.  The techniques mentioned above should make things a little easier and helpful in getting your WP7 application approved and published on the Marketplace.  The next blog post will be titled: WP7 Tips–Part II - How to write code that will pass the Windows Phone 7 Marketplace Requirements for Themes (light and dark). If anyone has any questions or comments please comment on this blog. 

  Read the article

• Using Radio Button in GridView with Validation

  - by Vincent Maverick Durano

  A developer is asking how to select one radio button at a time if the radio button is inside the GridView.  As you may know setting the group name attribute of radio button will not work if the radio button is located within a Data Representation control like GridView. This because the radio button inside the gridview bahaves differentely. Since a gridview is rendered as table element , at run time it will assign different "name" to each radio button. Hence you are able to select multiple rows. In this post I'm going to demonstrate how select one radio button at a time in gridview and add a simple validation on it. To get started let's go ahead and fire up visual studio and the create a new web application / website project. Add a WebForm and then add gridview. The mark up would look something like this: <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" > <Columns> <asp:TemplateField> <ItemTemplate> <asp:RadioButton ID="rb" runat="server" /> </ItemTemplate> </asp:TemplateField> <asp:BoundField DataField="RowNumber" HeaderText="Row Number" /> <asp:BoundField DataField="Col1" HeaderText="First Column" /> <asp:BoundField DataField="Col2" HeaderText="Second Column" /> </Columns> </asp:GridView> Noticed that I've added a templatefield column so that we can add the radio button there. Also I have set up some BoundField columns and set the DataFields as RowNumber, Col1 and Col2. These columns are just dummy columns and i used it for the simplicity of this example. Now where these columns came from? These columns are created by hand at the code behind file of the ASPX. Here's the code below: private DataTable FillData() { DataTable dt = new DataTable(); DataRow dr = null; //Create DataTable columns dt.Columns.Add(new DataColumn("RowNumber", typeof(string))); dt.Columns.Add(new DataColumn("Col1", typeof(string))); dt.Columns.Add(new DataColumn("Col2", typeof(string))); //Create Row for each columns dr = dt.NewRow(); dr["RowNumber"] = 1; dr["Col1"] = "A"; dr["Col2"] = "B"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["RowNumber"] = 2; dr["Col1"] = "AA"; dr["Col2"] = "BB"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["RowNumber"] = 3; dr["Col1"] = "A"; dr["Col2"] = "B"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["RowNumber"] = 4; dr["Col1"] = "A"; dr["Col2"] = "B"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["RowNumber"] = 5; dr["Col1"] = "A"; dr["Col2"] = "B"; dt.Rows.Add(dr); return dt; } And here's the code for binding the GridView with the dummy data above. protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { GridView1.DataSource = FillData(); GridView1.DataBind(); } } Okay we have now a GridView data with a radio button on each row. Now lets go ahead and switch back to ASPX mark up. In this example I'm going to use a JavaScript for validating the radio button to select one radio button at a time. Here's the javascript code below: function CheckOtherIsCheckedByGVID(rb) { var isChecked = rb.checked; var row = rb.parentNode.parentNode; if (isChecked) { row.style.backgroundColor = '#B6C4DE'; row.style.color = 'black'; } var currentRdbID = rb.id; parent = document.getElementById("<%= GridView1.ClientID %>"); var items = parent.getElementsByTagName('input'); for (i = 0; i < items.length; i++) { if (items[i].id != currentRdbID && items[i].type == "radio") { if (items[i].checked) { items[i].checked = false; items[i].parentNode.parentNode.style.backgroundColor = 'white'; items[i].parentNode.parentNode.style.color = '#696969'; } } } } The function above sets the row of the current selected radio button's style to determine that the row is selected and then loops through the radio buttons in the gridview and then de-select the previous selected radio button and set the row style back to its default. You can then call the javascript function above at onlick event of radio button like below: <asp:RadioButton ID="rb" runat="server" onclick="javascript:CheckOtherIsCheckedByGVID(this);" /> Here's the output below: On Load: After Selecting a Radio Button: As you have noticed, on initial load there's no default selected radio in the GridView. Now let's add a simple validation for that. We will basically display an error message if a user clicks a button that triggers a postback without selecting  a radio button in the GridView. Here's the javascript for the validation: function ValidateRadioButton(sender, args) { var gv = document.getElementById("<%= GridView1.ClientID %>"); var items = gv.getElementsByTagName('input'); for (var i = 0; i < items.length ; i++) { if (items[i].type == "radio") { if (items[i].checked) { args.IsValid = true; return; } else { args.IsValid = false; } } } } The function above loops through the rows in gridview and find all the radio buttons within it. It will then check each radio button checked property. If a radio is checked then set IsValid to true else set it to false.  The reason why I'm using IsValid is because I'm using the ASP validator control for validation. Now add the following mark up below under the GridView declaration: <br /> <asp:Label ID="lblMessage" runat="server" /> <br /> <asp:Button ID="btn" runat="server" Text="POST" onclick="btn_Click" ValidationGroup="GroupA" /> <asp:CustomValidator ID="CustomValidator1" runat="server" ErrorMessage="Please select row in the grid." ClientValidationFunction="ValidateRadioButton" ValidationGroup="GroupA" style="display:none"></asp:CustomValidator> <asp:ValidationSummary ID="ValidationSummary1" runat="server" ValidationGroup="GroupA" HeaderText="Error List:" DisplayMode="BulletList" ForeColor="Red" /> And then at Button Click event add this simple code below just to test if  the validation works: protected void btn_Click(object sender, EventArgs e) { lblMessage.Text = "Postback at: " + DateTime.Now.ToString("hh:mm:ss tt"); } Here's the output below that you can see in the browser:   That's it! I hope someone find this post useful! Technorati Tags: ASP.NET,JavaScript,GridView

  Read the article

• Read XML Files using LINQ to XML and Extension Methods

  - by psheriff

  In previous blog posts I have discussed how to use XML files to store data in your applications. I showed you how to read those XML files from your project and get XML from a WCF service. One of the problems with reading XML files is when elements or attributes are missing. If you try to read that missing data, then a null value is returned. This can cause a problem if you are trying to load that data into an object and a null is read. This blog post will show you how to create extension methods to detect null values and return valid values to load into your object. The XML Data An XML data file called Product.xml is located in the \Xml folder of the Silverlight sample project for this blog post. This XML file contains several rows of product data that will be used in each of the samples for this post. Each row has 4 attributes; namely ProductId, ProductName, IntroductionDate and Price. <Products>  <Product ProductId="1"           ProductName="Haystack Code Generator for .NET"           IntroductionDate="07/01/2010"  Price="799" />  <Product ProductId="2"           ProductName="ASP.Net Jumpstart Samples"           IntroductionDate="05/24/2005"  Price="0" />  ...  ...</Products> The Product Class Just as you create an Entity class to map each column in a table to a property in a class, you should do the same for an XML file too. In this case you will create a Product class with properties for each of the attributes in each element of product data. The following code listing shows the Product class. public class Product : CommonBase{  public const string XmlFile = @"Xml/Product.xml";   private string _ProductName;  private int _ProductId;  private DateTime _IntroductionDate;  private decimal _Price;   public string ProductName  {    get { return _ProductName; }    set {      if (_ProductName != value) {        _ProductName = value;        RaisePropertyChanged("ProductName");      }    }  }   public int ProductId  {    get { return _ProductId; }    set {      if (_ProductId != value) {        _ProductId = value;        RaisePropertyChanged("ProductId");      }    }  }   public DateTime IntroductionDate  {    get { return _IntroductionDate; }    set {      if (_IntroductionDate != value) {        _IntroductionDate = value;        RaisePropertyChanged("IntroductionDate");      }    }  }   public decimal Price  {    get { return _Price; }    set {      if (_Price != value) {        _Price = value;        RaisePropertyChanged("Price");      }    }  }} NOTE: The CommonBase class that the Product class inherits from simply implements the INotifyPropertyChanged event in order to inform your XAML UI of any property changes. You can see this class in the sample you download for this blog post. Reading Data When using LINQ to XML you call the Load method of the XElement class to load the XML file. Once the XML file has been loaded, you write a LINQ query to iterate over the “Product” Descendants in the XML file. The “select” portion of the LINQ query creates a new Product object for each row in the XML file. You retrieve each attribute by passing each attribute name to the Attribute() method and retrieving the data from the “Value” property. The Value property will return a null if there is no data, or will return the string value of the attribute. The Convert class is used to convert the value retrieved into the appropriate data type required by the Product class. private void LoadProducts(){  XElement xElem = null;   try  {    xElem = XElement.Load(Product.XmlFile);     // The following will NOT work if you have missing attributes    var products =         from elem in xElem.Descendants("Product")        orderby elem.Attribute("ProductName").Value        select new Product        {          ProductId = Convert.ToInt32(            elem.Attribute("ProductId").Value),          ProductName = Convert.ToString(            elem.Attribute("ProductName").Value),          IntroductionDate = Convert.ToDateTime(            elem.Attribute("IntroductionDate").Value),          Price = Convert.ToDecimal(elem.Attribute("Price").Value)        };     lstData.DataContext = products;  }  catch (Exception ex)  {    MessageBox.Show(ex.Message);  }} This is where the problem comes in. If you have any missing attributes in any of the rows in the XML file, or if the data in the ProductId or IntroductionDate is not of the appropriate type, then this code will fail! The reason? There is no built-in check to ensure that the correct type of data is contained in the XML file. This is where extension methods can come in real handy. Using Extension Methods Instead of using the Convert class to perform type conversions as you just saw, create a set of extension methods attached to the XAttribute class. These extension methods will perform null-checking and ensure that a valid value is passed back instead of an exception being thrown if there is invalid data in your XML file. private void LoadProducts(){  var xElem = XElement.Load(Product.XmlFile);   var products =       from elem in xElem.Descendants("Product")      orderby elem.Attribute("ProductName").Value      select new Product      {        ProductId = elem.Attribute("ProductId").GetAsInteger(),        ProductName = elem.Attribute("ProductName").GetAsString(),        IntroductionDate =            elem.Attribute("IntroductionDate").GetAsDateTime(),        Price = elem.Attribute("Price").GetAsDecimal()      };   lstData.DataContext = products;} Writing Extension Methods To create an extension method you will create a class with any name you like. In the code listing below is a class named XmlExtensionMethods. This listing just shows a couple of the available methods such as GetAsString and GetAsInteger. These methods are just like any other method you would write except when you pass in the parameter you prefix the type with the keyword “this”. This lets the compiler know that it should add this method to the class specified in the parameter. public static class XmlExtensionMethods{  public static string GetAsString(this XAttribute attr)  {    string ret = string.Empty;     if (attr != null && !string.IsNullOrEmpty(attr.Value))    {      ret = attr.Value;    }     return ret;  }   public static int GetAsInteger(this XAttribute attr)  {    int ret = 0;    int value = 0;     if (attr != null && !string.IsNullOrEmpty(attr.Value))    {      if(int.TryParse(attr.Value, out value))        ret = value;    }     return ret;  }   ...  ...} Each of the methods in the XmlExtensionMethods class should inspect the XAttribute to ensure it is not null and that the value in the attribute is not null. If the value is null, then a default value will be returned such as an empty string or a 0 for a numeric value. Summary Extension methods are a great way to simplify your code and provide protection to ensure problems do not occur when reading data. You will probably want to create more extension methods to handle XElement objects as well for when you use element-based XML. Feel free to extend these extension methods to accept a parameter which would be the default value if a null value is detected, or any other parameters you wish. NOTE: You can download the complete sample code at my website. http://www.pdsa.com/downloads. Choose “Tips & Tricks”, then "Read XML Files using LINQ to XML and Extension Methods" from the drop-down. Good Luck with your Coding,Paul D. Sheriff  

  Read the article

• Announcing Windows Azure Mobile Services

  - by ScottGu

  I’m excited to announce a new capability we are adding to Windows Azure today: Windows Azure Mobile Services Windows Azure Mobile Services makes it incredibly easy to connect a scalable cloud backend to your client and mobile applications.  It allows you to easily store structured data in the cloud that can span both devices and users, integrate it with user authentication, as well as send out updates to clients via push notifications. Today’s release enables you to add these capabilities to any Windows 8 app in literally minutes, and provides a super productive way for you to quickly build out your app ideas.  We’ll also be adding support to enable these same scenarios for Windows Phone, iOS, and Android devices soon. Read this getting started tutorial to walkthrough how you can build (in less than 5 minutes) a simple Windows 8 “Todo List” app that is cloud enabled using Windows Azure Mobile Services.  Or watch this video of me showing how to do it step by step. Getting Started If you don’t already have a Windows Azure account, you can sign up for a no-obligation Free Trial.  Once you are signed-up, click the “preview features” section under the “account” tab of the www.windowsazure.com website and enable your account to support the “Mobile Services” preview.   Instructions on how to enable this can be found here. Once you have the mobile services preview enabled, log into the Windows Azure Portal, click the “New” button and choose the new “Mobile Services” icon to create your first mobile backend.  Once created, you’ll see a quick-start page like below with instructions on how to connect your mobile service to an existing Windows 8 client app you have already started working on, or how to create and connect a brand-new Windows 8 client app with it: Read this getting started tutorial to walkthrough how you can build (in less than 5 minutes) a simple Windows 8 “Todo List” app  that stores data in Windows Azure. Storing Data in the Cloud Storing data in the cloud with Windows Azure Mobile Services is incredibly easy.  When you create a Windows Azure Mobile Service, we automatically associate it with a SQL Database inside Windows Azure.  The Windows Azure Mobile Service backend then provides built-in support for enabling remote apps to securely store and retrieve data from it (using secure REST end-points utilizing a JSON-based ODATA format) – without you having to write or deploy any custom server code.  Built-in management support is provided within the Windows Azure portal for creating new tables, browsing data, setting indexes, and controlling access permissions. This makes it incredibly easy to connect client applications to the cloud, and enables client developers who don’t have a server-code background to be productive from the very beginning.  They can instead focus on building the client app experience, and leverage Windows Azure Mobile Services to provide the cloud backend services they require.  Below is an example of client-side Windows 8 C#/XAML code that could be used to query data from a Windows Azure Mobile Service.  Client-side C# developers can write queries like this using LINQ and strongly typed POCO objects, which are then translated into HTTP REST queries that run against a Windows Azure Mobile Service.   Developers don’t have to write or deploy any custom server-side code in order to enable client-side code below to execute and asynchronously populate their client UI: Because Mobile Services is part of Windows Azure, developers can later choose to augment or extend their initial solution and add custom server functionality and more advanced logic if they want.  This provides maximum flexibility, and enables developers to grow and extend their solutions to meet any needs. User Authentication and Push Notifications Windows Azure Mobile Services also make it incredibly easy to integrate user authentication/authorization and push notifications within your applications.  You can use these capabilities to enable authentication and fine grain access control permissions to the data you store in the cloud, as well as to trigger push notifications to users/devices when the data changes.  Windows Azure Mobile Services supports the concept of “server scripts” (small chunks of server-side script that executes in response to actions) that make it really easy to enable these scenarios. Below are some tutorials that walkthrough common authentication/authorization/push scenarios you can do with Windows Azure Mobile Services and Windows 8 apps: Enabling User Authentication Authorizing Users  Get Started with Push Notifications Push Notifications to multiple Users Manage and Monitor your Mobile Service Just like with every other service in Windows Azure, you can monitor usage and metrics of your mobile service backend using the “Dashboard” tab within the Windows Azure Portal. The dashboard tab provides a built-in monitoring view of the API calls, Bandwidth, and server CPU cycles of your Windows Azure Mobile Service.   You can also use the “Logs” tab within the portal to review error messages.  This makes it easy to monitor and track how your application is doing. Scale Up as Your Business Grows Windows Azure Mobile Services now allows every Windows Azure customer to create and run up to 10 Mobile Services in a free, shared/multi-tenant hosting environment (where your mobile backend will be one of multiple apps running on a shared set of server resources).  This provides an easy way to get started on projects at no cost beyond the database you connect your Windows Azure Mobile Service to (note: each Windows Azure free trial account also includes a 1GB SQL Database that you can use with any number of apps or Windows Azure Mobile Services). If your client application becomes popular, you can click the “Scale” tab of your Mobile Service and switch from “Shared” to “Reserved” mode.  Doing so allows you to isolate your apps so that you are the only customer within a virtual machine.  This allows you to elastically scale the amount of resources your apps use – allowing you to scale-up (or scale-down) your capacity as your traffic grows: With Windows Azure you pay for compute capacity on a per-hour basis – which allows you to scale up and down your resources to match only what you need.  This enables a super flexible model that is ideal for new mobile app scenarios, as well as startups who are just getting going.  Summary I’ve only scratched the surface of what you can do with Windows Azure Mobile Services – there are a lot more features to explore.  With Windows Azure Mobile Services you’ll be able to build mobile app experiences faster than ever, and enable even better user experiences – by connecting your client apps to the cloud. Visit the Windows Azure Mobile Services development center to learn more, and build your first Windows 8 app connected with Windows Azure today.  And read this getting started tutorial to walkthrough how you can build (in less than 5 minutes) a simple Windows 8 “Todo List” app that is cloud enabled using Windows Azure Mobile Services. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

  Read the article

• On StringComparison Values

  - by Jesse

  When you use the .NET Framework’s String.Equals and String.Compare methods do you use an overloStringComparison enumeration value? If not, you should be because the value provided for that StringComparison argument can have a big impact on the results of your string comparison. The StringComparison enumeration defines values that fall into three different major categories: Culture-sensitive comparison using a specific culture, defaulted to the Thread.CurrentThread.CurrentCulture value (StringComparison.CurrentCulture and StringComparison.CurrentCutlureIgnoreCase) Invariant culture comparison (StringComparison.InvariantCulture and StringComparison.InvariantCultureIgnoreCase) Ordinal (byte-by-byte) comparison of  (StringComparison.Ordinal and StringComparison.OrdinalIgnoreCase) There is a lot of great material available that detail the technical ins and outs of these different string comparison approaches. If you’re at all interested in the topic these two MSDN articles are worth a read: Best Practices For Using Strings in the .NET Framework: http://msdn.microsoft.com/en-us/library/dd465121.aspx How To Compare Strings: http://msdn.microsoft.com/en-us/library/cc165449.aspx Those articles cover the technical details of string comparison well enough that I’m not going to reiterate them here other than to say that the upshot is that you typically want to use the culture-sensitive comparison whenever you’re comparing strings that were entered by or will be displayed to users and the ordinal comparison in nearly all other cases. So where does that leave the invariant culture comparisons? The “Best Practices For Using Strings in the .NET Framework” article has the following to say: “On balance, the invariant culture has very few properties that make it useful for comparison. It does comparison in a linguistically relevant manner, which prevents it from guaranteeing full symbolic equivalence, but it is not the choice for display in any culture. One of the few reasons to use StringComparison.InvariantCulture for comparison is to persist ordered data for a cross-culturally identical display. For example, if a large data file that contains a list of sorted identifiers for display accompanies an application, adding to this list would require an insertion with invariant-style sorting.” I don’t know about you, but I feel like that paragraph is a bit lacking. Are there really any “real world” reasons to use the invariant culture comparison? I think the answer to this question is, “yes”, but in order to understand why we should first think about what the invariant culture comparison really does. The invariant culture comparison is really just a culture-sensitive comparison using a special invariant culture (Michael Kaplan has a great post on the history of the invariant culture on his blog: http://blogs.msdn.com/b/michkap/archive/2004/12/29/344136.aspx). This means that the invariant culture comparison will apply the linguistic customs defined by the invariant culture which are guaranteed not to differ between different machines or execution contexts. This sort of consistently does prove useful if you needed to maintain a list of strings that are sorted in a meaningful and consistent way regardless of the user viewing them or the machine on which they are being viewed. Example: Prototype Names Let’s say that you work for a large multi-national toy company with branch offices in 10 different countries. Each year the company would work on 15-25 new toy prototypes each of which is assigned a “code name” while it is under development. Coming up with fun new code names is a big part of the company culture that everyone really enjoys, so to be fair the CEO of the company spent a lot of time coming up with a prototype naming scheme that would be fun for everyone to participate in, fair to all of the different branch locations, and accessible to all members of the organization regardless of the country they were from and the language that they spoke. Each new prototype will get a code name that begins with a letter following the previously created name using the alphabetical order of the Latin/Roman alphabet. Each new year prototype names would start back at “A”. The country that leads the prototype development effort gets to choose the name in their native language. (An appropriate Romanization system will be used for countries where the primary language is not written in the Latin/Roman alphabet. For example, the Pinyin system could be used for Chinese). To avoid repeating names, a list of all current and past prototype names will be maintained on each branch location’s company intranet site. Assuming that maintaining a single pre-sorted list is not feasible among all of the highly distributed intranet implementations, what string comparison method would you use to sort each year’s list of prototype names so that the list is both meaningful and consistent regardless of the country within which the list is being viewed? Sorting the list with a culture-sensitive comparison using the default configured culture on each country’s intranet server the list would probably work most of the time, but subtle differences between cultures could mean that two different people would see a list that was sorted slightly differently. The CEO wants the prototype names to be a unifying aspect of company culture and is adamant that everyone see the the same list sorted in the same order and there’s no way to guarantee a consistent sort across different cultures using the culture-sensitive string comparison rules. The culture-sensitive sort would produce a meaningful list for the specific user viewing it, but it wouldn’t always be consistent between different users. Sorting with the ordinal comparison would certainly be consistent regardless of the user viewing it, but would it be meaningful? Let’s say that the current year’s prototype name list looks like this: Antílope (Spanish) Babouin (French) Cahoun (Czech) Diamond (English) Flosse (German) If you were to sort this list using ordinal rules you’d end up with: Antílope Babouin Diamond Flosse Cahoun This sort is no good because the entry for “C” appears the bottom of the list after “F”. This is because the Czech entry for the letter “C” makes use of a diacritic (accent mark). The ordinal string comparison does a byte-by-byte comparison of the code points that make up each character in the string and the code point for the “C” with the diacritic mark is higher than any letter without a diacritic mark, which pushes that entry to the bottom of the sorted list. The CEO wants each country to be able to create prototype names in their native language, which means we need to allow for names that might begin with letters that have diacritics, so ordinal sorting kills the meaningfulness of the list. As it turns out, this situation is actually well-suited for the invariant culture comparison. The invariant culture accounts for linguistically relevant factors like the use of diacritics but will provide a consistent sort across all machines that perform the sort. Now that we’ve walked through this example, the following line from the “Best Practices For Using Strings in the .NET Framework” makes a lot more sense: One of the few reasons to use StringComparison.InvariantCulture for comparison is to persist ordered data for a cross-culturally identical display That line describes the prototype name example perfectly: we need a way to persist ordered data for a cross-culturally identical display. While this example is 100% made-up, I think it illustrates that there are indeed real-world situations where the invariant culture comparison is useful.

  Read the article

< Previous Page | 642 643 644 645 646 647 648 649 650 651 652 653  | Next Page >