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  • New Validation Attributes in ASP.NET MVC 3 Future

    - by imran_ku07
         Introduction:             Validating user inputs is an very important step in collecting information from users because it helps you to prevent errors during processing data. Incomplete or improperly formatted user inputs will create lot of problems for your application. Fortunately, ASP.NET MVC 3 makes it very easy to validate most common input validations. ASP.NET MVC 3 includes Required, StringLength, Range, RegularExpression, Compare and Remote validation attributes for common input validation scenarios. These validation attributes validates most of your user inputs but still validation for Email, File Extension, Credit Card, URL, etc are missing. Fortunately, some of these validation attributes are available in ASP.NET MVC 3 Future. In this article, I will show you how to leverage Email, Url, CreditCard and FileExtensions validation attributes(which are available in ASP.NET MVC 3 Future) in ASP.NET MVC 3 application.       Description:             First of all you need to download ASP.NET MVC 3 RTM Source Code from here. Then extract all files in a folder. Then open MvcFutures project from mvc3-rtm-sources\mvc3\src\MvcFutures folder. Build the project. In case, if you get compile time error(s) then simply remove the reference of System.Web.WebPages and System.Web.Mvc assemblies and add the reference of System.Web.WebPages and System.Web.Mvc 3 assemblies again but from the .NET tab and then build the project again, it will create a Microsoft.Web.Mvc assembly inside mvc3-rtm-sources\mvc3\src\MvcFutures\obj\Debug folder. Now we can use Microsoft.Web.Mvc assembly inside our application.             Create a new ASP.NET MVC 3 application. For demonstration purpose, I will create a dummy model UserInformation. So create a new class file UserInformation.cs inside Model folder and add the following code,   public class UserInformation { [Required] public string Name { get; set; } [Required] [EmailAddress] public string Email { get; set; } [Required] [Url] public string Website { get; set; } [Required] [CreditCard] public string CreditCard { get; set; } [Required] [FileExtensions(Extensions = "jpg,jpeg")] public string Image { get; set; } }             Inside UserInformation class, I am using Email, Url, CreditCard and FileExtensions validation attributes which are defined in Microsoft.Web.Mvc assembly. By default FileExtensionsAttribute allows png, jpg, jpeg and gif extensions. You can override this by using Extensions property of FileExtensionsAttribute class.             Then just open(or create) HomeController.cs file and add the following code,   public class HomeController : Controller { public ActionResult Index() { return View(); } [HttpPost] public ActionResult Index(UserInformation u) { return View(); } }             Next just open(or create) Index view for Home controller and add the following code,  @model NewValidationAttributesinASPNETMVC3Future.Model.UserInformation @{ ViewBag.Title = "Index"; Layout = "~/Views/Shared/_Layout.cshtml"; } <h2>Index</h2> <script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script> @using (Html.BeginForm()) { @Html.ValidationSummary(true) <fieldset> <legend>UserInformation</legend> <div class="editor-label"> @Html.LabelFor(model => model.Name) </div> <div class="editor-field"> @Html.EditorFor(model => model.Name) @Html.ValidationMessageFor(model => model.Name) </div> <div class="editor-label"> @Html.LabelFor(model => model.Email) </div> <div class="editor-field"> @Html.EditorFor(model => model.Email) @Html.ValidationMessageFor(model => model.Email) </div> <div class="editor-label"> @Html.LabelFor(model => model.Website) </div> <div class="editor-field"> @Html.EditorFor(model => model.Website) @Html.ValidationMessageFor(model => model.Website) </div> <div class="editor-label"> @Html.LabelFor(model => model.CreditCard) </div> <div class="editor-field"> @Html.EditorFor(model => model.CreditCard) @Html.ValidationMessageFor(model => model.CreditCard) </div> <div class="editor-label"> @Html.LabelFor(model => model.Image) </div> <div class="editor-field"> @Html.EditorFor(model => model.Image) @Html.ValidationMessageFor(model => model.Image) </div> <p> <input type="submit" value="Save" /> </p> </fieldset> } <div> @Html.ActionLink("Back to List", "Index") </div>             Now just run your application. You will find that both client side and server side validation for the above validation attributes works smoothly.                      Summary:             Email, URL, Credit Card and File Extension input validations are very common. In this article, I showed you how you can validate these input validations into your application. I explained this with an example. I am also attaching a sample application which also includes Microsoft.Web.Mvc.dll. So you can add a reference of Microsoft.Web.Mvc assembly directly instead of doing any manual work. Hope you will enjoy this article too.   SyntaxHighlighter.all()

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  • More FlipBoard Magazines: Azure, XAML, ASP.NET MVC & Web API

    - by dwahlin
    In a previous post I introduced two new FlipBoard magazines that I put together including The AngularJS Magazine and The JavaScript & HTML5 Magazine. FlipBoard magazines provide a great way to keep content organized using a magazine-style format as opposed to trudging through multiple unorganized bookmarks or boring pages full of links. I think they’re really fun to read through as well. Based on feedback and the surprising popularity of the first two magazines I’ve decided to create some additional magazines on topics I like such as The Azure Magazine, The XAML Magazine and The ASP.NET MVC & Web API Magazine. Click on a cover below to get to the magazines using your browser. To subscribe to a given magazine you’ll need to create a FlipBoard account (not required to read the magazines though) which requires an iOS or Android device (the Windows Phone 8 app is coming soon they say). If you have a post or article that you think would be a good fit for any of the magazines please tweet the link to @DanWahlin and I’ll add it to my queue to review. I plan to be pretty strict about keeping articles “on topic” and focused.   The Azure Magazine   The XAML Magazine   The ASP.NET MVC & Web API Magazine   The AngularJS Magazine   The JavaScript & HTML5 Magazine

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  • SimpleMembership, Membership Providers, Universal Providers and the new ASP.NET 4.5 Web Forms and ASP.NET MVC 4 templates

    - by Jon Galloway
    The ASP.NET MVC 4 Internet template adds some new, very useful features which are built on top of SimpleMembership. These changes add some great features, like a much simpler and extensible membership API and support for OAuth. However, the new account management features require SimpleMembership and won't work against existing ASP.NET Membership Providers. I'll start with a summary of top things you need to know, then dig into a lot more detail. Summary: SimpleMembership has been designed as a replacement for traditional the previous ASP.NET Role and Membership provider system SimpleMembership solves common problems people ran into with the Membership provider system and was designed for modern user / membership / storage needs SimpleMembership integrates with the previous membership system, but you can't use a MembershipProvider with SimpleMembership The new ASP.NET MVC 4 Internet application template AccountController requires SimpleMembership and is not compatible with previous MembershipProviders You can continue to use existing ASP.NET Role and Membership providers in ASP.NET 4.5 and ASP.NET MVC 4 - just not with the ASP.NET MVC 4 AccountController The existing ASP.NET Role and Membership provider system remains supported as is part of the ASP.NET core ASP.NET 4.5 Web Forms does not use SimpleMembership; it implements OAuth on top of ASP.NET Membership The ASP.NET Web Site Administration Tool (WSAT) is not compatible with SimpleMembership The following is the result of a few conversations with Erik Porter (PM for ASP.NET MVC) to make sure I had some the overall details straight, combined with a lot of time digging around in ILSpy and Visual Studio's assembly browsing tools. SimpleMembership: The future of membership for ASP.NET The ASP.NET Membership system was introduces with ASP.NET 2.0 back in 2005. It was designed to solve common site membership requirements at the time, which generally involved username / password based registration and profile storage in SQL Server. It was designed with a few extensibility mechanisms - notably a provider system (which allowed you override some specifics like backing storage) and the ability to store additional profile information (although the additional  profile information was packed into a single column which usually required access through the API). While it's sometimes frustrating to work with, it's held up for seven years - probably since it handles the main use case (username / password based membership in a SQL Server database) smoothly and can be adapted to most other needs (again, often frustrating, but it can work). The ASP.NET Web Pages and WebMatrix efforts allowed the team an opportunity to take a new look at a lot of things - e.g. the Razor syntax started with ASP.NET Web Pages, not ASP.NET MVC. The ASP.NET Web Pages team designed SimpleMembership to (wait for it) simplify the task of dealing with membership. As Matthew Osborn said in his post Using SimpleMembership With ASP.NET WebPages: With the introduction of ASP.NET WebPages and the WebMatrix stack our team has really be focusing on making things simpler for the developer. Based on a lot of customer feedback one of the areas that we wanted to improve was the built in security in ASP.NET. So with this release we took that time to create a new built in (and default for ASP.NET WebPages) security provider. I say provider because the new stuff is still built on the existing ASP.NET framework. So what do we call this new hotness that we have created? Well, none other than SimpleMembership. SimpleMembership is an umbrella term for both SimpleMembership and SimpleRoles. Part of simplifying membership involved fixing some common problems with ASP.NET Membership. Problems with ASP.NET Membership ASP.NET Membership was very obviously designed around a set of assumptions: Users and user information would most likely be stored in a full SQL Server database or in Active Directory User and profile information would be optimized around a set of common attributes (UserName, Password, IsApproved, CreationDate, Comment, Role membership...) and other user profile information would be accessed through a profile provider Some problems fall out of these assumptions. Requires Full SQL Server for default cases The default, and most fully featured providers ASP.NET Membership providers (SQL Membership Provider, SQL Role Provider, SQL Profile Provider) require full SQL Server. They depend on stored procedure support, and they rely on SQL Server cache dependencies, they depend on agents for clean up and maintenance. So the main SQL Server based providers don't work well on SQL Server CE, won't work out of the box on SQL Azure, etc. Note: Cory Fowler recently let me know about these Updated ASP.net scripts for use with Microsoft SQL Azure which do support membership, personalization, profile, and roles. But the fact that we need a support page with a set of separate SQL scripts underscores the underlying problem. Aha, you say! Jon's forgetting the Universal Providers, a.k.a. System.Web.Providers! Hold on a bit, we'll get to those... Custom Membership Providers have to work with a SQL-Server-centric API If you want to work with another database or other membership storage system, you need to to inherit from the provider base classes and override a bunch of methods which are tightly focused on storing a MembershipUser in a relational database. It can be done (and you can often find pretty good ones that have already been written), but it's a good amount of work and often leaves you with ugly code that has a bunch of System.NotImplementedException fun since there are a lot of methods that just don't apply. Designed around a specific view of users, roles and profiles The existing providers are focused on traditional membership - a user has a username and a password, some specific roles on the site (e.g. administrator, premium user), and may have some additional "nice to have" optional information that can be accessed via an API in your application. This doesn't fit well with some modern usage patterns: In OAuth and OpenID, the user doesn't have a password Often these kinds of scenarios map better to user claims or rights instead of monolithic user roles For many sites, profile or other non-traditional information is very important and needs to come from somewhere other than an API call that maps to a database blob What would work a lot better here is a system in which you were able to define your users, rights, and other attributes however you wanted and the membership system worked with your model - not the other way around. Requires specific schema, overflow in blob columns I've already mentioned this a few times, but it bears calling out separately - ASP.NET Membership focuses on SQL Server storage, and that storage is based on a very specific database schema. SimpleMembership as a better membership system As you might have guessed, SimpleMembership was designed to address the above problems. Works with your Schema As Matthew Osborn explains in his Using SimpleMembership With ASP.NET WebPages post, SimpleMembership is designed to integrate with your database schema: All SimpleMembership requires is that there are two columns on your users table so that we can hook up to it – an “ID” column and a “username” column. The important part here is that they can be named whatever you want. For instance username doesn't have to be an alias it could be an email column you just have to tell SimpleMembership to treat that as the “username” used to log in. Matthew's example shows using a very simple user table named Users (it could be named anything) with a UserID and Username column, then a bunch of other columns he wanted in his app. Then we point SimpleMemberhip at that table with a one-liner: WebSecurity.InitializeDatabaseFile("SecurityDemo.sdf", "Users", "UserID", "Username", true); No other tables are needed, the table can be named anything we want, and can have pretty much any schema we want as long as we've got an ID and something that we can map to a username. Broaden database support to the whole SQL Server family While SimpleMembership is not database agnostic, it works across the SQL Server family. It continues to support full SQL Server, but it also works with SQL Azure, SQL Server CE, SQL Server Express, and LocalDB. Everything's implemented as SQL calls rather than requiring stored procedures, views, agents, and change notifications. Note that SimpleMembership still requires some flavor of SQL Server - it won't work with MySQL, NoSQL databases, etc. You can take a look at the code in WebMatrix.WebData.dll using a tool like ILSpy if you'd like to see why - there places where SQL Server specific SQL statements are being executed, especially when creating and initializing tables. It seems like you might be able to work with another database if you created the tables separately, but I haven't tried it and it's not supported at this point. Note: I'm thinking it would be possible for SimpleMembership (or something compatible) to run Entity Framework so it would work with any database EF supports. That seems useful to me - thoughts? Note: SimpleMembership has the same database support - anything in the SQL Server family - that Universal Providers brings to the ASP.NET Membership system. Easy to with Entity Framework Code First The problem with with ASP.NET Membership's system for storing additional account information is that it's the gate keeper. That means you're stuck with its schema and accessing profile information through its API. SimpleMembership flips that around by allowing you to use any table as a user store. That means you're in control of the user profile information, and you can access it however you'd like - it's just data. Let's look at a practical based on the AccountModel.cs class in an ASP.NET MVC 4 Internet project. Here I'm adding a Birthday property to the UserProfile class. [Table("UserProfile")] public class UserProfile { [Key] [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)] public int UserId { get; set; } public string UserName { get; set; } public DateTime Birthday { get; set; } } Now if I want to access that information, I can just grab the account by username and read the value. var context = new UsersContext(); var username = User.Identity.Name; var user = context.UserProfiles.SingleOrDefault(u => u.UserName == username); var birthday = user.Birthday; So instead of thinking of SimpleMembership as a big membership API, think of it as something that handles membership based on your user database. In SimpleMembership, everything's keyed off a user row in a table you define rather than a bunch of entries in membership tables that were out of your control. How SimpleMembership integrates with ASP.NET Membership Okay, enough sales pitch (and hopefully background) on why things have changed. How does this affect you? Let's start with a diagram to show the relationship (note: I've simplified by removing a few classes to show the important relationships): So SimpleMembershipProvider is an implementaiton of an ExtendedMembershipProvider, which inherits from MembershipProvider and adds some other account / OAuth related things. Here's what ExtendedMembershipProvider adds to MembershipProvider: The important thing to take away here is that a SimpleMembershipProvider is a MembershipProvider, but a MembershipProvider is not a SimpleMembershipProvider. This distinction is important in practice: you cannot use an existing MembershipProvider (including the Universal Providers found in System.Web.Providers) with an API that requires a SimpleMembershipProvider, including any of the calls in WebMatrix.WebData.WebSecurity or Microsoft.Web.WebPages.OAuth.OAuthWebSecurity. However, that's as far as it goes. Membership Providers still work if you're accessing them through the standard Membership API, and all of the core stuff  - including the AuthorizeAttribute, role enforcement, etc. - will work just fine and without any change. Let's look at how that affects you in terms of the new templates. Membership in the ASP.NET MVC 4 project templates ASP.NET MVC 4 offers six Project Templates: Empty - Really empty, just the assemblies, folder structure and a tiny bit of basic configuration. Basic - Like Empty, but with a bit of UI preconfigured (css / images / bundling). Internet - This has both a Home and Account controller and associated views. The Account Controller supports registration and login via either local accounts and via OAuth / OpenID providers. Intranet - Like the Internet template, but it's preconfigured for Windows Authentication. Mobile - This is preconfigured using jQuery Mobile and is intended for mobile-only sites. Web API - This is preconfigured for a service backend built on ASP.NET Web API. Out of these templates, only one (the Internet template) uses SimpleMembership. ASP.NET MVC 4 Basic template The Basic template has configuration in place to use ASP.NET Membership with the Universal Providers. You can see that configuration in the ASP.NET MVC 4 Basic template's web.config: <profile defaultProvider="DefaultProfileProvider"> <providers> <add name="DefaultProfileProvider" type="System.Web.Providers.DefaultProfileProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" applicationName="/" /> </providers> </profile> <membership defaultProvider="DefaultMembershipProvider"> <providers> <add name="DefaultMembershipProvider" type="System.Web.Providers.DefaultMembershipProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="false" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10" applicationName="/" /> </providers> </membership> <roleManager defaultProvider="DefaultRoleProvider"> <providers> <add name="DefaultRoleProvider" type="System.Web.Providers.DefaultRoleProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" applicationName="/" /> </providers> </roleManager> <sessionState mode="InProc" customProvider="DefaultSessionProvider"> <providers> <add name="DefaultSessionProvider" type="System.Web.Providers.DefaultSessionStateProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" /> </providers> </sessionState> This means that it's business as usual for the Basic template as far as ASP.NET Membership works. ASP.NET MVC 4 Internet template The Internet template has a few things set up to bootstrap SimpleMembership: \Models\AccountModels.cs defines a basic user account and includes data annotations to define keys and such \Filters\InitializeSimpleMembershipAttribute.cs creates the membership database using the above model, then calls WebSecurity.InitializeDatabaseConnection which verifies that the underlying tables are in place and marks initialization as complete (for the application's lifetime) \Controllers\AccountController.cs makes heavy use of OAuthWebSecurity (for OAuth account registration / login / management) and WebSecurity. WebSecurity provides account management services for ASP.NET MVC (and Web Pages) WebSecurity can work with any ExtendedMembershipProvider. There's one in the box (SimpleMembershipProvider) but you can write your own. Since a standard MembershipProvider is not an ExtendedMembershipProvider, WebSecurity will throw exceptions if the default membership provider is a MembershipProvider rather than an ExtendedMembershipProvider. Practical example: Create a new ASP.NET MVC 4 application using the Internet application template Install the Microsoft ASP.NET Universal Providers for LocalDB NuGet package Run the application, click on Register, add a username and password, and click submit You'll get the following execption in AccountController.cs::Register: To call this method, the "Membership.Provider" property must be an instance of "ExtendedMembershipProvider". This occurs because the ASP.NET Universal Providers packages include a web.config transform that will update your web.config to add the Universal Provider configuration I showed in the Basic template example above. When WebSecurity tries to use the configured ASP.NET Membership Provider, it checks if it can be cast to an ExtendedMembershipProvider before doing anything else. So, what do you do? Options: If you want to use the new AccountController, you'll either need to use the SimpleMembershipProvider or another valid ExtendedMembershipProvider. This is pretty straightforward. If you want to use an existing ASP.NET Membership Provider in ASP.NET MVC 4, you can't use the new AccountController. You can do a few things: Replace  the AccountController.cs and AccountModels.cs in an ASP.NET MVC 4 Internet project with one from an ASP.NET MVC 3 application (you of course won't have OAuth support). Then, if you want, you can go through and remove other things that were built around SimpleMembership - the OAuth partial view, the NuGet packages (e.g. the DotNetOpenAuthAuth package, etc.) Use an ASP.NET MVC 4 Internet application template and add in a Universal Providers NuGet package. Then copy in the AccountController and AccountModel classes. Create an ASP.NET MVC 3 project and upgrade it to ASP.NET MVC 4 using the steps shown in the ASP.NET MVC 4 release notes. None of these are particularly elegant or simple. Maybe we (or just me?) can do something to make this simpler - perhaps a NuGet package. However, this should be an edge case - hopefully the cases where you'd need to create a new ASP.NET but use legacy ASP.NET Membership Providers should be pretty rare. Please let me (or, preferably the team) know if that's an incorrect assumption. Membership in the ASP.NET 4.5 project template ASP.NET 4.5 Web Forms took a different approach which builds off ASP.NET Membership. Instead of using the WebMatrix security assemblies, Web Forms uses Microsoft.AspNet.Membership.OpenAuth assembly. I'm no expert on this, but from a bit of time in ILSpy and Visual Studio's (very pretty) dependency graphs, this uses a Membership Adapter to save OAuth data into an EF managed database while still running on top of ASP.NET Membership. Note: There may be a way to use this in ASP.NET MVC 4, although it would probably take some plumbing work to hook it up. How does this fit in with Universal Providers (System.Web.Providers)? Just to summarize: Universal Providers are intended for cases where you have an existing ASP.NET Membership Provider and you want to use it with another SQL Server database backend (other than SQL Server). It doesn't require agents to handle expired session cleanup and other background tasks, it piggybacks these tasks on other calls. Universal Providers are not really, strictly speaking, universal - at least to my way of thinking. They only work with databases in the SQL Server family. Universal Providers do not work with Simple Membership. The Universal Providers packages include some web config transforms which you would normally want when you're using them. What about the Web Site Administration Tool? Visual Studio includes tooling to launch the Web Site Administration Tool (WSAT) to configure users and roles in your application. WSAT is built to work with ASP.NET Membership, and is not compatible with Simple Membership. There are two main options there: Use the WebSecurity and OAuthWebSecurity API to manage the users and roles Create a web admin using the above APIs Since SimpleMembership runs on top of your database, you can update your users as you would any other data - via EF or even in direct database edits (in development, of course)

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  • Entity Framework 4.0: Optimal and horrible SQL

    - by DigiMortal
    Lately I had Entity Framework 4.0 session where I introduced new features of Entity Framework. During session I found out with audience how Entity Framework 4.0 can generate optimized SQL. After session I also showed guys one horrible example about how awful SQL can be generated by Entity Framework. In this posting I will cover both examples. Optimal SQL Before going to code take a look at following model. There is class called Event and I will use this class in my query. Here is the LINQ To Entities query that uses small anonymous type. var query = from e in _context.Events             select new { Id = e.Id, Title = e.Title }; Debug.WriteLine(((ObjectQuery)query).ToTraceString()); Running this code gives us the following SQL. SELECT      [Extent1].[event_id] AS [event_id],      [Extent1].[title] AS [title]  FROM [dbo].[events] AS [Extent1] This is really small – no additional fields in SELECT clause. Nice, isn’t it? Horrible SQL Ayende Rahien blog shows us darker side of Entiry Framework 4.0 queries. You can find comparison betwenn NHibernate, LINQ To SQL and LINQ To Entities from posting What happens behind the scenes: NHibernate, Linq to SQL, Entity Framework scenario analysis. In this posting I will show you the resulting query and let you think how much better it can be done. Well, it is not something we want to see running in our servers. I hope that EF team improves generated SQL to acceptable level before Visual Studio 2010 is released. There is also morale of this example: you should always check out the queries that O/R-mapper generates. Behind the curtains it may silently generate queries that perform badly and in this case you need to optimize you data querying strategy. Conclusion Entity Framework 4.0 is new product with a lot of new features and it is clear that not everything is 100% super in its first release. But it still great step forward and I hope that on 12.04.2010 we have new promising O/R-mapper available to use in our projects. If you want to read more about Entity Framework 4.0 and Visual Studio 2010 then please feel free to follow this link to list of my Visual Studio 2010 and .NET Framework 4.0 postings.

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  • Using multiple diagrams per model in Entity Framework 5.0

    - by nikolaosk
    I have downloaded .Net framework 4.5 and Visual Studio 2012 since it was released to MSDN subscribers on the 15th of August.For people that do not know about that yet please have a look at Jason Zander's excellent blog post .Since then I have been investigating the many new features that have been introduced in this release.In this post I will be looking into theIn order to follow along this post you must have Visual Studio 2012 and .Net Framework 4.5 installed in your machine.Download and install VS 20120 using this link.My machine runs on Windows 8 and Visual Studio 2012 works just fine. I have also installed in my machine SQL Server 2012 developer edition. I have also downloaded and installed AdventureWorksLT2012 database.You can download this database from the codeplex website.   Before I start showcasing the demo I want to say that I strongly believe that Entity Framework is maturing really fast and now at version 5.0 can be used as your data access layer in all your .Net projects.I have posted extensively about Entity Framework in my blog.Please find all the EF related posts here. In this demo I will show you how to split an entity model into multiple diagrams using the new enhanced EF designer. We will not build an application in this demo.Sometimes our model can become too large to edit or view.In earlier versions we could only have one diagram per EDMX file.In EF 5.0 we can split the model into more diagrams.1) Launch VS 2012. Express edition will work fine.2) Create a New Project. From the available templates choose a Web Forms application  3) Add a new item in your project, an ADO.Net Entity Data Model. I have named it AdventureWorksLT.edmx.Then we will create the model from the database and click Next.Create a new connection by specifying the SQL Server instance and the database name and click OK.Then click Next in the wizard.In the next screen of the wizard select all the tables from the database and hit Finish.4) It will take a while for our .edmx diagram to be created. When I select an Entity (e.g Customer) from my diagram and right click on it,a new option appears "Move to new Diagram".Make sure you have the Model Browser window open.Have a look at the picture below 5) When we do that a new diagram is created and our new Entity is moved there.Have a look at the picture below  6) We can also right-click and include the related entities. Have a look at the picture below. 7) When we do that the related entities are copied to the new diagram.Have a look at the picture below  8) Now we can cut (CTRL+X) the entities from Diagram2 and paste them back to Diagram1.9) Finally another great enhancement of the EF 5.0 designer is that you can change colors in the various entities that make up the model.Select the entities you want to change color, then in the Properties window choose the color of your choice. Have a look at the picture below. To recap we have demonstrated how to split your entity model in multiple diagrams which comes handy in EF models that have a large number of entities in them Hope it helps!!!!

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  • April 30th Links: ASP.NET, ASP.NET MVC, Visual Studio 2010

    - by ScottGu
    Here is the latest in my link-listing series. [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] ASP.NET Data Web Control Enhancements in ASP.NET 4.0: Scott Mitchell has a good article that summarizes some of the nice improvements coming to the ASP.NET 4 data controls. Refreshing an ASP.NET AJAX UpdatePanel with JavaScript: Scott Mitchell has another nice article in his series on using ASP.NET AJAX that demonstrates how to programmatically trigger an UpdatePanel refresh using JavaScript on the client. ASP.NET MVC ASP.NET MVC 2: Basics and Introduction: Scott Hanselman delivers an awesome introductory talk on ASP.NET MVC.  Great for people looking to understand and learn ASP.NET MVC. ASP.NET MVC 2: Ninja Black Belt Tips: Another great talk by Scott Hanselman about how to make the most of several features of ASP.NET MVC 2. ASP.NET MVC 2 Html.Editor/Display Templates: A great blog post detailing the new Html.EditorFor() and Html.DisplayFor() helpers within ASP.NET MVC 2. MVCContrib Grid: Jeremy Skinner’s video presentation about the new Html.Grid() helper component within the (most awesome) MvcContrib project for ASP.NET MVC. Code Snippets for ASP.NET MVC 2 in VS 2010: Raj Kaimal documents some of the new code snippets for ASP.NET MVC 2 that are now built-into Visual Studio 2010.  Read this article to learn how to do common scenarios with fewer keystrokes. Turn on Compile-time View Checking for ASP.NET MVC Projects in TFS 2010 Build: Jim Lamb has a nice post that describes how to enable compile-time view checking as part of automated builds done with a TFS Build Server.  This will ensure any errors in your view templates raise build-errors (allowing you to catch them at build-time instead of runtime). Visual Studio 2010 VS 2010 Keyboard Shortcut Posters for VB, C#, F# and C++: Keyboard shortcut posters that you can download and then printout. Ideal to provide a quick reference on your desk for common keystroke actions inside VS 2010. My Favorite New Features in VS 2010: Scott Mitchell has a nice article that summarizes some of his favorite new features in VS 2010.  Check out my VS 2010 and .NET 4 blog series for more details on some of them. 6 Cool VS 2010 Quick Tips and Features: Anoop has a nice blog post describing 6 cool features of VS 2010 that you can take advantage of. SharePoint Development with VS 2010: Beth Massi links to a bunch of nice “How do I?” videos that that demonstrate how to use the SharePoint development support built-into VS 2010. How to Pin a Project to the Recent Projects List in VS 2010: A useful tip/trick that demonstrates how to “pin” a project to always show up on the “Recent Projects” list within Visual Studio 2010. Using the WPF Tree Visualizer in VS 2010: Zain blogs about the new WPF Tree Visualizer supported by the VS 2010 debugger.  This makes it easier to visualize WPF control hierarchies within the debugger. TFS 2010 Power Tools Released: Brian Harry blogs about the cool new TFS 2010 extensions released with this week’s TFS 2010 Power Tools release. What is New with T4 in VS 2010: T4 is the name of Visual Studio’s template-based code generation technology.  Lots of scenarios within VS 2010 now use T4 for code generation customization. Two examples are ASP.NET MVC Views and EF4 Model Generation.  This post describes some of the many T4 infrastructure improvements in VS 2010. Hope this helps, Scott P.S. If you haven’t already, check out this month’s "Find a Hoster” page on the www.asp.net website to learn about great (and very inexpensive) ASP.NET hosting offers.

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  • Importing Multiple Schemas to a Model in Oracle SQL Developer Data Modeler

    - by thatjeffsmith
    Your physical data model might stretch across multiple Oracle schemas. Or maybe you just want a single diagram containing tables, views, etc. spanning more than a single user in the database. The process for importing a data dictionary is the same, regardless if you want to suck in objects from one schema, or many schemas. Let’s take a quick look at how to get started with a data dictionary import. I’m using Oracle SQL Developer in this example. The process is nearly identical in Oracle SQL Developer Data Modeler – the only difference being you’ll use the ‘File’ menu to get started versus the ‘File – Data Modeler’ menu in SQL Developer. Remember, the functionality is exactly the same whether you use SQL Developer or SQL Developer Data Modeler when it comes to the data modeling features – you’ll just have a cleaner user interface in SQL Developer Data Modeler. Importing a Data Dictionary to a Model You’ll want to open or create your model first. You can import objects to an existing or new model. The easiest way to get started is to simply open the ‘Browser’ under the View menu. The Browser allows you to navigate your open designs/models You’ll see an ‘Untitled_1′ model by default. I’ve renamed mine to ‘hr_sh_scott_demo.’ Now go back to the File menu, and expand the ‘Data Modeler’ section, and select ‘Import – Data Dictionary.’ This is a fancy way of saying, ‘suck objects out of the database into my model’ Connect! If you haven’t already defined a connection to the database you want to reverse engineer, you’ll need to do that now. I’m going to assume you already have that connection – so select it, and hit the ‘Next’ button. Select the Schema(s) to be imported Select one or more schemas you want to import The schemas selected on this page of the wizard will dictate the lists of tables, views, synonyms, and everything else you can choose from in the next wizard step to import. For brevity, I have selected ALL tables, views, and synonyms from 3 different schemas: HR SCOTT SH Once I hit the ‘Finish’ button in the wizard, SQL Developer will interrogate the database and add the objects to our model. The Big Model and the 3 Little Models I can now see ALL of the objects I just imported in the ‘hr_sh_scott_demo’ relational model in my design tree, and in my relational diagram. Quick Tip: Oracle SQL Developer calls what most folks think of as a ‘Physical Model’ the ‘Relational Model.’ Same difference, mostly. In SQL Developer, a Physical model allows you to define partitioning schemes, advanced storage parameters, and add your PL/SQL code. You can have multiple physical models per relational models. For example I might have a 4 Node RAC in Production that uses partitioning, but in test/dev, only have a single instance with no partitioning. I can have models for both of those physical implementations. The list of tables in my relational model Wouldn’t it be nice if I could segregate the objects based on their schema? Good news, you can! And it’s done by default Several of you might already know where I’m going with this – SUBVIEWS. You can easily create a ‘SubView’ by selecting one or more objects in your model or diagram and add them to a new SubView. SubViews are just mini-models. They contain a subset of objects from the main model. This is very handy when you want to break your model into smaller, more digestible parts. The model information is identical across the model and subviews, so you don’t have to worry about making a change in one place and not having it propagate across your design. SubViews can be used as filters when you create reports and exports as well. So instead of generating a PDF for everything, just show me what’s in my ‘ABC’ subview. But, I don’t want to do any work! Remember, I’m really lazy. More good news – it’s already done by default! The schemas are automatically used to create default SubViews Auto-Navigate to the Object in the Diagram In the subview tree node, right-click on the object you want to navigate to. You can ask to be taken to the main model view or to the SubView location. If you haven’t already opened the SubView in the diagram, it will be automatically opened for you. The SubView diagram only contains the objects from that SubView Your SubView might still be pretty big, many dozens of objects, so don’t forget about the ‘Navigator‘ either! In summary, use the ‘Import’ feature to add existing database objects to your model. If you import from multiple schemas, take advantage of the default schema based SubViews to help you manage your models! Sometimes less is more!

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  • Generically correcting data before save with Entity Framework

    - by koevoeter
    Been working with Entity Framework (.NET 4.0) for a week now for a data migration job and needed some code that generically corrects string values in the database. You probably also have seen things like empty strings instead of NULL or non-trimmed texts ("United States       ") in "old" databases, and you don't want to apply a correcting function on every column you migrate. Here's how I've done this (extending the partial class of my ObjectContext):public partial class MyDatacontext{    partial void OnContextCreated()    {        SavingChanges += OnSavingChanges;    }     private void OnSavingChanges(object sender, EventArgs e)    {        foreach (var entity in GetPersistingEntities(sender))        {            foreach (var propertyInfo in GetStringProperties(entity))            {                var value = (string)propertyInfo.GetValue(entity, null);                 if (value == null)                {                    continue;                }                 if (value.Trim().Length == 0 && IsNullable(propertyInfo))                {                    propertyInfo.SetValue(entity, null, null);                }                else if (value != value.Trim())                {                    propertyInfo.SetValue(entity, value.Trim(), null);                }            }        }    }     private IEnumerable<object> GetPersistingEntities(object sender)    {        return ((ObjectContext)sender).ObjectStateManager            .GetObjectStateEntries(EntityState.Added | EntityState.Modified)             .Select(e => e.Entity);    }    private IEnumerable<PropertyInfo> GetStringProperties(object entity)    {        return entity.GetType().GetProperties()            .Where(pi => pi.PropertyType == typeof(string));    }    private bool IsNullable(PropertyInfo propertyInfo)    {        return ((EdmScalarPropertyAttribute)propertyInfo             .GetCustomAttributes(typeof(EdmScalarPropertyAttribute), false)            .Single()).IsNullable;    }}   Obviously you can use similar code for other generic corrections.

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  • Join with ADO.NET Linq to Entity in C#

    - by aladdin
    Hello I'm try to migrate a system to ADO.NET Entity I have 3 table A => (Id, Name, ...) B => (Id, Domain, ...) c => (IdA, IdB) VS.NET generate 2 entity A and B and both have reference to the other table but this reference is a collection. I need make a join between tables. from a in A join b in B on a.? equal b.? where condition select new { Name = a.Name, Domain = b.Domain }; I cant do that follow the reference in entity bu when the problem grows can be a problem. Any Help?

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  • DevDays ‘00 The Netherlands day #1

    - by erwin21
    First day of DevDays 2010, I was looking forward to DevDays to see all the new things like VS2010, .NET4.0, MVC2. The lineup for this year is again better than the year before, there are 100+ session of all kind of topics like Cloud, Database, Mobile, SharePoint, User experience, Visual Studio, Web. The first session of the day was a keynote by Anders Hejlsberg he talked about the history and future of programming languages. He gave his view about trends and influences in programming languages today and in the future. The second talk that i followed was from the famous Scott Hanselman, he talked about the basics of ASP.NET MVC 2, although it was a 300 level session, it was more like a level 100 session, but it was mentioned by Scott at the beginning. Although it was interesting to see all the basic things about MVC like the controllers, actions, routes, views, models etc. After the lunch the third talk for me was about moving ASP.NET webform applications to MVC from Fritz Onion. In this session he changed an example webform application part by part to a MVC application. He gave some interesting tips and tricks and showed how to solve some issues that occur while converting. Next and the fourth talk was about the difference between LINQ to SQL and  the ADO.NET  Entity Framework from Kurt Claeys. He gave a good understanding about this two options, the demos where in LINQ to SQL and the Entity Framework, the goal was to get a good understanding when and where to use both options. The last talk about this day was also from Scott Hanselman, he goes deeper into the features of ASP.NET MVC 2 and gave some interesting tips, the ninja black belt tips. He gave some tips about the tooling, the new MVC 2 html helper methods, other view engines (like NHaml, spark),T4 templating. With this tips we can be more productive and create web applications better and faster. It was a long and interesting day, I am looking forward to day #2.

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  • Inheritance Mapping Strategies with Entity Framework Code First CTP5 Part 1: Table per Hierarchy (TPH)

    - by mortezam
    A simple strategy for mapping classes to database tables might be “one table for every entity persistent class.” This approach sounds simple enough and, indeed, works well until we encounter inheritance. Inheritance is such a visible structural mismatch between the object-oriented and relational worlds because object-oriented systems model both “is a” and “has a” relationships. SQL-based models provide only "has a" relationships between entities; SQL database management systems don’t support type inheritance—and even when it’s available, it’s usually proprietary or incomplete. There are three different approaches to representing an inheritance hierarchy: Table per Hierarchy (TPH): Enable polymorphism by denormalizing the SQL schema, and utilize a type discriminator column that holds type information. Table per Type (TPT): Represent "is a" (inheritance) relationships as "has a" (foreign key) relationships. Table per Concrete class (TPC): Discard polymorphism and inheritance relationships completely from the SQL schema.I will explain each of these strategies in a series of posts and this one is dedicated to TPH. In this series we'll deeply dig into each of these strategies and will learn about "why" to choose them as well as "how" to implement them. Hopefully it will give you a better idea about which strategy to choose in a particular scenario. Inheritance Mapping with Entity Framework Code FirstAll of the inheritance mapping strategies that we discuss in this series will be implemented by EF Code First CTP5. The CTP5 build of the new EF Code First library has been released by ADO.NET team earlier this month. EF Code-First enables a pretty powerful code-centric development workflow for working with data. I’m a big fan of the EF Code First approach, and I’m pretty excited about a lot of productivity and power that it brings. When it comes to inheritance mapping, not only Code First fully supports all the strategies but also gives you ultimate flexibility to work with domain models that involves inheritance. The fluent API for inheritance mapping in CTP5 has been improved a lot and now it's more intuitive and concise in compare to CTP4. A Note For Those Who Follow Other Entity Framework ApproachesIf you are following EF's "Database First" or "Model First" approaches, I still recommend to read this series since although the implementation is Code First specific but the explanations around each of the strategies is perfectly applied to all approaches be it Code First or others. A Note For Those Who are New to Entity Framework and Code-FirstIf you choose to learn EF you've chosen well. If you choose to learn EF with Code First you've done even better. To get started, you can find a great walkthrough by Scott Guthrie here and another one by ADO.NET team here. In this post, I assume you already setup your machine to do Code First development and also that you are familiar with Code First fundamentals and basic concepts. You might also want to check out my other posts on EF Code First like Complex Types and Shared Primary Key Associations. A Top Down Development ScenarioThese posts take a top-down approach; it assumes that you’re starting with a domain model and trying to derive a new SQL schema. Therefore, we start with an existing domain model, implement it in C# and then let Code First create the database schema for us. However, the mapping strategies described are just as relevant if you’re working bottom up, starting with existing database tables. I’ll show some tricks along the way that help you dealing with nonperfect table layouts. Let’s start with the mapping of entity inheritance. -- The Domain ModelIn our domain model, we have a BillingDetail base class which is abstract (note the italic font on the UML class diagram below). We do allow various billing types and represent them as subclasses of BillingDetail class. As for now, we support CreditCard and BankAccount: Implement the Object Model with Code First As always, we start with the POCO classes. Note that in our DbContext, I only define one DbSet for the base class which is BillingDetail. Code First will find the other classes in the hierarchy based on Reachability Convention. public abstract class BillingDetail  {     public int BillingDetailId { get; set; }     public string Owner { get; set; }             public string Number { get; set; } } public class BankAccount : BillingDetail {     public string BankName { get; set; }     public string Swift { get; set; } } public class CreditCard : BillingDetail {     public int CardType { get; set; }                     public string ExpiryMonth { get; set; }     public string ExpiryYear { get; set; } } public class InheritanceMappingContext : DbContext {     public DbSet<BillingDetail> BillingDetails { get; set; } } This object model is all that is needed to enable inheritance with Code First. If you put this in your application you would be able to immediately start working with the database and do CRUD operations. Before going into details about how EF Code First maps this object model to the database, we need to learn about one of the core concepts of inheritance mapping: polymorphic and non-polymorphic queries. Polymorphic Queries LINQ to Entities and EntitySQL, as object-oriented query languages, both support polymorphic queries—that is, queries for instances of a class and all instances of its subclasses, respectively. For example, consider the following query: IQueryable<BillingDetail> linqQuery = from b in context.BillingDetails select b; List<BillingDetail> billingDetails = linqQuery.ToList(); Or the same query in EntitySQL: string eSqlQuery = @"SELECT VAlUE b FROM BillingDetails AS b"; ObjectQuery<BillingDetail> objectQuery = ((IObjectContextAdapter)context).ObjectContext                                                                          .CreateQuery<BillingDetail>(eSqlQuery); List<BillingDetail> billingDetails = objectQuery.ToList(); linqQuery and eSqlQuery are both polymorphic and return a list of objects of the type BillingDetail, which is an abstract class but the actual concrete objects in the list are of the subtypes of BillingDetail: CreditCard and BankAccount. Non-polymorphic QueriesAll LINQ to Entities and EntitySQL queries are polymorphic which return not only instances of the specific entity class to which it refers, but all subclasses of that class as well. On the other hand, Non-polymorphic queries are queries whose polymorphism is restricted and only returns instances of a particular subclass. In LINQ to Entities, this can be specified by using OfType<T>() Method. For example, the following query returns only instances of BankAccount: IQueryable<BankAccount> query = from b in context.BillingDetails.OfType<BankAccount>() select b; EntitySQL has OFTYPE operator that does the same thing: string eSqlQuery = @"SELECT VAlUE b FROM OFTYPE(BillingDetails, Model.BankAccount) AS b"; In fact, the above query with OFTYPE operator is a short form of the following query expression that uses TREAT and IS OF operators: string eSqlQuery = @"SELECT VAlUE TREAT(b as Model.BankAccount)                       FROM BillingDetails AS b                       WHERE b IS OF(Model.BankAccount)"; (Note that in the above query, Model.BankAccount is the fully qualified name for BankAccount class. You need to change "Model" with your own namespace name.) Table per Class Hierarchy (TPH)An entire class hierarchy can be mapped to a single table. This table includes columns for all properties of all classes in the hierarchy. The concrete subclass represented by a particular row is identified by the value of a type discriminator column. You don’t have to do anything special in Code First to enable TPH. It's the default inheritance mapping strategy: This mapping strategy is a winner in terms of both performance and simplicity. It’s the best-performing way to represent polymorphism—both polymorphic and nonpolymorphic queries perform well—and it’s even easy to implement by hand. Ad-hoc reporting is possible without complex joins or unions. Schema evolution is straightforward. Discriminator Column As you can see in the DB schema above, Code First has to add a special column to distinguish between persistent classes: the discriminator. This isn’t a property of the persistent class in our object model; it’s used internally by EF Code First. By default, the column name is "Discriminator", and its type is string. The values defaults to the persistent class names —in this case, “BankAccount” or “CreditCard”. EF Code First automatically sets and retrieves the discriminator values. TPH Requires Properties in SubClasses to be Nullable in the Database TPH has one major problem: Columns for properties declared by subclasses will be nullable in the database. For example, Code First created an (INT, NULL) column to map CardType property in CreditCard class. However, in a typical mapping scenario, Code First always creates an (INT, NOT NULL) column in the database for an int property in persistent class. But in this case, since BankAccount instance won’t have a CardType property, the CardType field must be NULL for that row so Code First creates an (INT, NULL) instead. If your subclasses each define several non-nullable properties, the loss of NOT NULL constraints may be a serious problem from the point of view of data integrity. TPH Violates the Third Normal FormAnother important issue is normalization. We’ve created functional dependencies between nonkey columns, violating the third normal form. Basically, the value of Discriminator column determines the corresponding values of the columns that belong to the subclasses (e.g. BankName) but Discriminator is not part of the primary key for the table. As always, denormalization for performance can be misleading, because it sacrifices long-term stability, maintainability, and the integrity of data for immediate gains that may be also achieved by proper optimization of the SQL execution plans (in other words, ask your DBA). Generated SQL QueryLet's take a look at the SQL statements that EF Code First sends to the database when we write queries in LINQ to Entities or EntitySQL. For example, the polymorphic query for BillingDetails that you saw, generates the following SQL statement: SELECT  [Extent1].[Discriminator] AS [Discriminator],  [Extent1].[BillingDetailId] AS [BillingDetailId],  [Extent1].[Owner] AS [Owner],  [Extent1].[Number] AS [Number],  [Extent1].[BankName] AS [BankName],  [Extent1].[Swift] AS [Swift],  [Extent1].[CardType] AS [CardType],  [Extent1].[ExpiryMonth] AS [ExpiryMonth],  [Extent1].[ExpiryYear] AS [ExpiryYear] FROM [dbo].[BillingDetails] AS [Extent1] WHERE [Extent1].[Discriminator] IN ('BankAccount','CreditCard') Or the non-polymorphic query for the BankAccount subclass generates this SQL statement: SELECT  [Extent1].[BillingDetailId] AS [BillingDetailId],  [Extent1].[Owner] AS [Owner],  [Extent1].[Number] AS [Number],  [Extent1].[BankName] AS [BankName],  [Extent1].[Swift] AS [Swift] FROM [dbo].[BillingDetails] AS [Extent1] WHERE [Extent1].[Discriminator] = 'BankAccount' Note how Code First adds a restriction on the discriminator column and also how it only selects those columns that belong to BankAccount entity. Change Discriminator Column Data Type and Values With Fluent API Sometimes, especially in legacy schemas, you need to override the conventions for the discriminator column so that Code First can work with the schema. The following fluent API code will change the discriminator column name to "BillingDetailType" and the values to "BA" and "CC" for BankAccount and CreditCard respectively: protected override void OnModelCreating(System.Data.Entity.ModelConfiguration.ModelBuilder modelBuilder) {     modelBuilder.Entity<BillingDetail>()                 .Map<BankAccount>(m => m.Requires("BillingDetailType").HasValue("BA"))                 .Map<CreditCard>(m => m.Requires("BillingDetailType").HasValue("CC")); } Also, changing the data type of discriminator column is interesting. In the above code, we passed strings to HasValue method but this method has been defined to accepts a type of object: public void HasValue(object value); Therefore, if for example we pass a value of type int to it then Code First not only use our desired values (i.e. 1 & 2) in the discriminator column but also changes the column type to be (INT, NOT NULL): modelBuilder.Entity<BillingDetail>()             .Map<BankAccount>(m => m.Requires("BillingDetailType").HasValue(1))             .Map<CreditCard>(m => m.Requires("BillingDetailType").HasValue(2)); SummaryIn this post we learned about Table per Hierarchy as the default mapping strategy in Code First. The disadvantages of the TPH strategy may be too serious for your design—after all, denormalized schemas can become a major burden in the long run. Your DBA may not like it at all. In the next post, we will learn about Table per Type (TPT) strategy that doesn’t expose you to this problem. References ADO.NET team blog Java Persistence with Hibernate book a { text-decoration: none; } a:visited { color: Blue; } .title { padding-bottom: 5px; font-family: Segoe UI; font-size: 11pt; font-weight: bold; padding-top: 15px; } .code, .typeName { font-family: consolas; } .typeName { color: #2b91af; } .padTop5 { padding-top: 5px; } .padTop10 { padding-top: 10px; } p.MsoNormal { margin-top: 0in; margin-right: 0in; margin-bottom: 10.0pt; margin-left: 0in; line-height: 115%; font-size: 11.0pt; font-family: "Calibri" , "sans-serif"; }

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  • How to model my database when using entity framework 4?

    - by Junior Ewing
    Trying to wrap my head around the best approach in modelling a database when we are using Entity Framework 4 as the ORM layer. We are going to use asp.net mvc 2 for the application. Is it worth trying to model using the class diagram modeller that comes with Visual Studio 2010 where you graphically configure your models into the EDMX file and then generate out the database structure? I have run into a bunch of non trivial issues and for complex many to many mappings or multi primary key entities the answer is not that obvious even after poking around a while with the tools. I figure its easy at this point to give up and start modelling the DB using real, working DB modelling tools and then try to generate out the EDMX from the database, rather than trying to do the model first approach.

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  • Start/Stop Window Service from ASP.NET page

    - by kaushalparik27
    Last week, I needed to complete one task on which I am going to blog about in this entry. The task is "Create a control panel like webpage to control (Start/Stop) Window Services which are part of my solution installed on computer where the main application is hosted". Here are the important points to accomplish:[1] You need to add System.ServiceProcess reference in your application. This namespace holds ServiceController Class to access the window service.[2] You need to check the status of the window services before you explicitly start or stop it.[3] By default, IIS application runs under ASP.NET account which doesn't have access rights permission to window service. So, Very Important part of the solution is: Impersonation. You need to impersonate the application/part of the code with the User Credentials which is having proper rights and permission to access the window service. If you try to access window service it will generate "access denied" error.The alternatives are: You can either impersonate whole application by adding Identity tag in web.cofig as:        <identity impersonate="true" userName="" password=""/>This tag will be under System.Web section. the "userName" and "password" will be the credentials of the user which is having rights to access the window service. But, this would not be a wise and good solution; because you may not impersonate whole website like this just to have access window service (which is going to be a small part of code).Second alternative is: Only impersonate part of code where you need to access the window service to start or stop it. I opted this one. But, to be fair; I am really unaware of the code part for impersonation. So, I just googled it and injected the code in my solution in a separate class file named as "Impersonate" with required static methods. In Impersonate class; impersonateValidUser() is the method to impersonate a part of code and undoImpersonation() is the method to undo the impersonation. Below is one example:  You need to provide domain name (which is "." if you are working on your home computer), username and password of appropriate user to impersonate.[4] Here, it is very important to note that: You need to have to store the Access Credentials (username and password) which you are going to user for impersonation; to some secured and encrypted format. I have used Machinekey Encryption to store the value encrypted value inside database.[5] So now; The real part is to start or stop a window service. You are almost done; because ServiceController class has simple Start() and Stop() methods to start or stop a window service. A ServiceController class has parametrized constructor that takes name of the service as parameter.Code to Start the window service: Code to Stop the window service: Isn't that too easy! ServiceController made it easy :) I have attached a working example with this post here to start/stop "SQLBrowser" service where you need to provide proper credentials who have permission to access to window service.  hope it would helps./.

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  • .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); })();

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  • Migrating ASP.NET (MVC 2) on .NET 3.5 over to .NET 4

    - by Charlino
    I've currently got a ASP.NET MVC 2 application on .NET 3.5 and I want to migrate it over to the new .NET 4.0 with Visual Studio 2010. Reason being that it's always good to stay on top of these things - plus I really like the new automatic encoding with <%: %> and clean web.config :-) So, does anyone have any experience they could share? Looking for gotchas and the likes. I guess this could also apply to any ASP.NET Forms projects aswell. TIA, Charles

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  • Migrating ASP.NET (MVC 2) on .NET 3.5 over to .NET 4 #gotchas

    - by Charlino
    I've currently got a ASP.NET MVC 2 application on .NET 3.5 and I want to migrate it over to the new .NET 4.0 with Visual Studio 2010. Reason being that it's always good to stay on top of these things - plus I really like the new automatic encoding with <%: %> and clean web.config :-) So, does anyone have any experience they could share? Looking for gotchas and the likes. I guess this could also apply to any ASP.NET Forms projects aswell. TIA, Charles

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  • delete data using entity framework

    - by user3474542
    The objective of the method below is to delete the data from the database using entity framework. I am populating the subscriptions entity by passing two parameters and then calling the atttach and remove method of the context class. Bureau entities is the context class. using (BUREAUEntities bureauEntities = new BUREAUEntities()) { var subscription = new SubcriptionRepository().GetSusbcriptionBySubscriptionTypeId(subscriptionTypeId, companyId); bureauEntities.Subscriptions.Attach((DataAccessLayer.DatabaseModel.Subscription)subscription); bureauEntities.Subscriptions.Remove(subscription); bureauEntities.SaveChanges(); } I am getting the following error message at An entity object cannot be referenced by multiple instances of IEntityChangeTracker at line bureauEntities.Subscriptions.Attach((DataAccessLayer.DatabaseModel.Subscription)subscription); Could somebody tell me where am I going wrong ?

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  • Announcing release of ASP.NET MVC 3, IIS Express, SQL CE 4, Web Farm Framework, Orchard, WebMatrix

    - by ScottGu
    I’m excited to announce the release today of several products: ASP.NET MVC 3 NuGet IIS Express 7.5 SQL Server Compact Edition 4 Web Deploy and Web Farm Framework 2.0 Orchard 1.0 WebMatrix 1.0 The above products are all free. They build upon the .NET 4 and VS 2010 release, and add a ton of additional value to ASP.NET (both Web Forms and MVC) and the Microsoft Web Server stack. ASP.NET MVC 3 Today we are shipping the final release of ASP.NET MVC 3.  You can download and install ASP.NET MVC 3 here.  The ASP.NET MVC 3 source code (released under an OSI-compliant open source license) can also optionally be downloaded here. ASP.NET MVC 3 is a significant update that brings with it a bunch of great features.  Some of the improvements include: Razor ASP.NET MVC 3 ships with a new view-engine option called “Razor” (in addition to continuing to support/enhance the existing .aspx view engine).  Razor minimizes the number of characters and keystrokes required when writing a view template, and enables a fast, fluid coding workflow. Unlike most template syntaxes, with Razor you do not need to interrupt your coding to explicitly denote the start and end of server blocks within your HTML. The Razor parser is smart enough to infer this from your code. This enables a compact and expressive syntax which is clean, fast and fun to type.  You can learn more about Razor from some of the blog posts I’ve done about it over the last 6 months Introducing Razor New @model keyword in Razor Layouts with Razor Server-Side Comments with Razor Razor’s @: and <text> syntax Implicit and Explicit code nuggets with Razor Layouts and Sections with Razor Today’s release supports full code intellisense support for Razor (both VB and C#) with Visual Studio 2010 and the free Visual Web Developer 2010 Express. JavaScript Improvements ASP.NET MVC 3 enables richer JavaScript scenarios and takes advantage of emerging HTML5 capabilities. The AJAX and Validation helpers in ASP.NET MVC 3 now use an Unobtrusive JavaScript based approach.  Unobtrusive JavaScript avoids injecting inline JavaScript into HTML, and enables cleaner separation of behavior using the new HTML 5 “data-“ attribute convention (which conveniently works on older browsers as well – including IE6). This keeps your HTML tight and clean, and makes it easier to optionally swap out or customize JS libraries.  ASP.NET MVC 3 now includes built-in support for posting JSON-based parameters from client-side JavaScript to action methods on the server.  This makes it easier to exchange data across the client and server, and build rich JavaScript front-ends.  We think this capability will be particularly useful going forward with scenarios involving client templates and data binding (including the jQuery plugins the ASP.NET team recently contributed to the jQuery project).  Previous releases of ASP.NET MVC included the core jQuery library.  ASP.NET MVC 3 also now ships the jQuery Validate plugin (which our validation helpers use for client-side validation scenarios).  We are also now shipping and including jQuery UI by default as well (which provides a rich set of client-side JavaScript UI widgets for you to use within projects). Improved Validation ASP.NET MVC 3 includes a bunch of validation enhancements that make it even easier to work with data. Client-side validation is now enabled by default with ASP.NET MVC 3 (using an onbtrusive javascript implementation).  Today’s release also includes built-in support for Remote Validation - which enables you to annotate a model class with a validation attribute that causes ASP.NET MVC to perform a remote validation call to a server method when validating input on the client. The validation features introduced within .NET 4’s System.ComponentModel.DataAnnotations namespace are now supported by ASP.NET MVC 3.  This includes support for the new IValidatableObject interface – which enables you to perform model-level validation, and allows you to provide validation error messages specific to the state of the overall model, or between two properties within the model.  ASP.NET MVC 3 also supports the improvements made to the ValidationAttribute class in .NET 4.  ValidationAttribute now supports a new IsValid overload that provides more information about the current validation context, such as what object is being validated.  This enables richer scenarios where you can validate the current value based on another property of the model.  We’ve shipped a built-in [Compare] validation attribute  with ASP.NET MVC 3 that uses this support and makes it easy out of the box to compare and validate two property values. You can use any data access API or technology with ASP.NET MVC.  This past year, though, we’ve worked closely with the .NET data team to ensure that the new EF Code First library works really well for ASP.NET MVC applications.  These two posts of mine cover the latest EF Code First preview and demonstrates how to use it with ASP.NET MVC 3 to enable easy editing of data (with end to end client+server validation support).  The final release of EF Code First will ship in the next few weeks. Today we are also publishing the first preview of a new MvcScaffolding project.  It enables you to easily scaffold ASP.NET MVC 3 Controllers and Views, and works great with EF Code-First (and is pluggable to support other data providers).  You can learn more about it – and install it via NuGet today - from Steve Sanderson’s MvcScaffolding blog post. Output Caching Previous releases of ASP.NET MVC supported output caching content at a URL or action-method level. With ASP.NET MVC V3 we are also enabling support for partial page output caching – which allows you to easily output cache regions or fragments of a response as opposed to the entire thing.  This ends up being super useful in a lot of scenarios, and enables you to dramatically reduce the work your application does on the server.  The new partial page output caching support in ASP.NET MVC 3 enables you to easily re-use cached sub-regions/fragments of a page across multiple URLs on a site.  It supports the ability to cache the content either on the web-server, or optionally cache it within a distributed cache server like Windows Server AppFabric or memcached. I’ll post some tutorials on my blog that show how to take advantage of ASP.NET MVC 3’s new output caching support for partial page scenarios in the future. Better Dependency Injection ASP.NET MVC 3 provides better support for applying Dependency Injection (DI) and integrating with Dependency Injection/IOC containers. With ASP.NET MVC 3 you no longer need to author custom ControllerFactory classes in order to enable DI with Controllers.  You can instead just register a Dependency Injection framework with ASP.NET MVC 3 and it will resolve dependencies not only for Controllers, but also for Views, Action Filters, Model Binders, Value Providers, Validation Providers, and Model Metadata Providers that you use within your application. This makes it much easier to cleanly integrate dependency injection within your projects. Other Goodies ASP.NET MVC 3 includes dozens of other nice improvements that help to both reduce the amount of code you write, and make the code you do write cleaner.  Here are just a few examples: Improved New Project dialog that makes it easy to start new ASP.NET MVC 3 projects from templates. Improved Add->View Scaffolding support that enables the generation of even cleaner view templates. New ViewBag property that uses .NET 4’s dynamic support to make it easy to pass late-bound data from Controllers to Views. Global Filters support that allows specifying cross-cutting filter attributes (like [HandleError]) across all Controllers within an app. New [AllowHtml] attribute that allows for more granular request validation when binding form posted data to models. Sessionless controller support that allows fine grained control over whether SessionState is enabled on a Controller. New ActionResult types like HttpNotFoundResult and RedirectPermanent for common HTTP scenarios. New Html.Raw() helper to indicate that output should not be HTML encoded. New Crypto helpers for salting and hashing passwords. And much, much more… Learn More about ASP.NET MVC 3 We will be posting lots of tutorials and samples on the http://asp.net/mvc site in the weeks ahead.  Below are two good ASP.NET MVC 3 tutorials available on the site today: Build your First ASP.NET MVC 3 Application: VB and C# Building the ASP.NET MVC 3 Music Store We’ll post additional ASP.NET MVC 3 tutorials and videos on the http://asp.net/mvc site in the future. Visit it regularly to find new tutorials as they are published. How to Upgrade Existing Projects ASP.NET MVC 3 is compatible with ASP.NET MVC 2 – which means it should be easy to update existing MVC projects to ASP.NET MVC 3.  The new features in ASP.NET MVC 3 build on top of the foundational work we’ve already done with the MVC 1 and MVC 2 releases – which means that the skills, knowledge, libraries, and books you’ve acquired are all directly applicable with the MVC 3 release.  MVC 3 adds new features and capabilities – it doesn’t obsolete existing ones. You can upgrade existing ASP.NET MVC 2 projects by following the manual upgrade steps in the release notes.  Alternatively, you can use this automated ASP.NET MVC 3 upgrade tool to easily update your  existing projects. Localized Builds Today’s ASP.NET MVC 3 release is available in English.  We will be releasing localized versions of ASP.NET MVC 3 (in 9 languages) in a few days.  I’ll blog pointers to the localized downloads once they are available. NuGet Today we are also shipping NuGet – a free, open source, package manager that makes it easy for you to find, install, and use open source libraries in your projects. It works with all .NET project types (including ASP.NET Web Forms, ASP.NET MVC, WPF, WinForms, Silverlight, and Class Libraries).  You can download and install it here. NuGet enables developers who maintain open source projects (for example, .NET projects like Moq, NHibernate, Ninject, StructureMap, NUnit, Windsor, Raven, Elmah, etc) to package up their libraries and register them with an online gallery/catalog that is searchable.  The client-side NuGet tools – which include full Visual Studio integration – make it trivial for any .NET developer who wants to use one of these libraries to easily find and install it within the project they are working on. NuGet handles dependency management between libraries (for example: library1 depends on library2). It also makes it easy to update (and optionally remove) libraries from your projects later. It supports updating web.config files (if a package needs configuration settings). It also allows packages to add PowerShell scripts to a project (for example: scaffold commands). Importantly, NuGet is transparent and clean – and does not install anything at the system level. Instead it is focused on making it easy to manage libraries you use with your projects. Our goal with NuGet is to make it as simple as possible to integrate open source libraries within .NET projects.  NuGet Gallery This week we also launched a beta version of the http://nuget.org web-site – which allows anyone to easily search and browse an online gallery of open source packages available via NuGet.  The site also now allows developers to optionally submit new packages that they wish to share with others.  You can learn more about how to create and share a package here. There are hundreds of open-source .NET projects already within the NuGet Gallery today.  We hope to have thousands there in the future. IIS Express 7.5 Today we are also shipping IIS Express 7.5.  IIS Express is a free version of IIS 7.5 that is optimized for developer scenarios.  It works for both ASP.NET Web Forms and ASP.NET MVC project types. We think IIS Express combines the ease of use of the ASP.NET Web Server (aka Cassini) currently built-into Visual Studio today with the full power of IIS.  Specifically: It’s lightweight and easy to install (less than 5Mb download and a quick install) It does not require an administrator account to run/debug applications from Visual Studio It enables a full web-server feature set – including SSL, URL Rewrite, and other IIS 7.x modules It supports and enables the same extensibility model and web.config file settings that IIS 7.x support It can be installed side-by-side with the full IIS web server as well as the ASP.NET Development Server (they do not conflict at all) It works on Windows XP and higher operating systems – giving you a full IIS 7.x developer feature-set on all Windows OS platforms IIS Express (like the ASP.NET Development Server) can be quickly launched to run a site from a directory on disk.  It does not require any registration/configuration steps. This makes it really easy to launch and run for development scenarios.  You can also optionally redistribute IIS Express with your own applications if you want a lightweight web-server.  The standard IIS Express EULA now includes redistributable rights. Visual Studio 2010 SP1 adds support for IIS Express.  Read my VS 2010 SP1 and IIS Express blog post to learn more about what it enables.  SQL Server Compact Edition 4 Today we are also shipping SQL Server Compact Edition 4 (aka SQL CE 4).  SQL CE is a free, embedded, database engine that enables easy database storage. No Database Installation Required SQL CE does not require you to run a setup or install a database server in order to use it.  You can simply copy the SQL CE binaries into the \bin directory of your ASP.NET application, and then your web application can use it as a database engine.  No setup or extra security permissions are required for it to run. You do not need to have an administrator account on the machine. Just copy your web application onto any server and it will work. This is true even of medium-trust applications running in a web hosting environment. SQL CE runs in-memory within your ASP.NET application and will start-up when you first access a SQL CE database, and will automatically shutdown when your application is unloaded.  SQL CE databases are stored as files that live within the \App_Data folder of your ASP.NET Applications. Works with Existing Data APIs SQL CE 4 works with existing .NET-based data APIs, and supports a SQL Server compatible query syntax.  This means you can use existing data APIs like ADO.NET, as well as use higher-level ORMs like Entity Framework and NHibernate with SQL CE.  This enables you to use the same data programming skills and data APIs you know today. Supports Development, Testing and Production Scenarios SQL CE can be used for development scenarios, testing scenarios, and light production usage scenarios.  With the SQL CE 4 release we’ve done the engineering work to ensure that SQL CE won’t crash or deadlock when used in a multi-threaded server scenario (like ASP.NET).  This is a big change from previous releases of SQL CE – which were designed for client-only scenarios and which explicitly blocked running in web-server environments.  Starting with SQL CE 4 you can use it in a web-server as well. There are no license restrictions with SQL CE.  It is also totally free. Tooling Support with VS 2010 SP1 Visual Studio 2010 SP1 adds support for SQL CE 4 and ASP.NET Projects.  Read my VS 2010 SP1 and SQL CE 4 blog post to learn more about what it enables.  Web Deploy and Web Farm Framework 2.0 Today we are also releasing Microsoft Web Deploy V2 and Microsoft Web Farm Framework V2.  These services provide a flexible and powerful way to deploy ASP.NET applications onto either a single server, or across a web farm of machines. You can learn more about these capabilities from my previous blog posts on them: Introducing the Microsoft Web Farm Framework Automating Deployment with Microsoft Web Deploy Visit the http://iis.net website to learn more and install them. Both are free. Orchard 1.0 Today we are also releasing Orchard v1.0.  Orchard is a free, open source, community based project.  It provides Content Management System (CMS) and Blogging System support out of the box, and makes it possible to easily create and manage web-sites without having to write code (site owners can customize a site through the browser-based editing tools built-into Orchard).  Read these tutorials to learn more about how you can setup and manage your own Orchard site. Orchard itself is built as an ASP.NET MVC 3 application using Razor view templates (and by default uses SQL CE 4 for data storage).  Developers wishing to extend an Orchard site with custom functionality can open and edit it as a Visual Studio project – and add new ASP.NET MVC Controllers/Views to it.  WebMatrix 1.0 WebMatrix is a new, free, web development tool from Microsoft that provides a suite of technologies that make it easier to enable website development.  It enables a developer to start a new site by browsing and downloading an app template from an online gallery of web applications (which includes popular apps like Umbraco, DotNetNuke, Orchard, WordPress, Drupal and Joomla).  Alternatively it also enables developers to create and code web sites from scratch. WebMatrix is task focused and helps guide developers as they work on sites.  WebMatrix includes IIS Express, SQL CE 4, and ASP.NET - providing an integrated web-server, database and programming framework combination.  It also includes built-in web publishing support which makes it easy to find and deploy sites to web hosting providers. You can learn more about WebMatrix from my Introducing WebMatrix blog post this summer.  Visit http://microsoft.com/web to download and install it today. Summary I’m really excited about today’s releases – they provide a bunch of additional value that makes web development with ASP.NET, Visual Studio and the Microsoft Web Server a lot better.  A lot of folks worked hard to share this with you today. On behalf of my whole team – we hope you enjoy them! 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

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  • March 21st Links: ASP.NET, ASP.NET MVC, AJAX, Visual Studio, Silverlight

    - by ScottGu
    Here is the latest in my link-listing series. If you haven’t already, check out this month’s "Find a Hoster” page on the www.asp.net website to learn about great (and very inexpensive) ASP.NET hosting offers.  [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] ASP.NET URL Routing in ASP.NET 4: Scott Mitchell has a nice article that talks about the new URL routing features coming to Web Forms applications with ASP.NET 4.  Also check out my previous blog post on this topic. Control of Web Control ClientID Values in ASP.NET 4: Scott Mitchell has a nice article that describes how it is now easy to control the client “id” value emitted by server controls with ASP.NET 4. Web Deployment Made Awesome: Very nice MIX10 talk by Scott Hanselman on the new web deployment features coming with VS 2010, MSDeploy, and .NET 4.  Makes deploying web applications much, much easier. ASP.NET 4’s Browser Capabilities Support: Nice blog post by Stephen Walther that talks about the new browser definition capabilities support coming with ASP.NET 4. Integrating Twitter into an ASP.NET Website: Nice article by Scott Mitchell that demonstrates how to call and integrate Twitter from within your ASP.NET applications. Improving CSS with .LESS: Nice article by Scott Mitchell that describes how to optimize CSS using .LESS – a free, open source library. ASP.NET MVC Upgrading ASP.NET MVC 1 applications to ASP.NET MVC 2: Eilon Lipton from the ASP.NET team has a nice post that describes how to easily upgrade your ASP.NET MVC 1 applications to ASP.NET MVC 2.  He has an automated tool that makes this easy. Note that automated MVC upgrade support is also built-into VS 2010.  Use the tool in this blog post for updating existing MVC projects using VS 2008. Advanced ASP.NET MVC 2: Nice video talk by Brad Wilson of the ASP.NET MVC team.  In it he describes some of the more advanced features in ASP.NET MVC 2 and how to maximize your productivity with them. Dynamic Select Lists with ASP.NET MVC and jQuery: Michael Ceranski has a nice blog post that describes how to dynamically populate dropdownlists on the client using AJAX. AJAX Microsoft AJAX Minifier: We recently shipped an updated minifier utility that allows you to shrink/minify both JavaScript and CSS files – which can improve the performance of your web applications.  You can run this either manually as a command-line tool or now automatically integrate it using a Visual Studio build task.  You can download it for free here. Visual Studio VS 2010 Tip: Quickly Closing Documents: Nice blog post that describes some techniques for optimizing how windows are closed with the new VS 2010 IDE. Collpase to Definitions with Outlining: Nice tip from Zain on how to collapse your code editor to outline mode using Ctrl + M, Ctrl + O.  Also check out his post on copy/paste with outlining here. $299 VS 2010 Upgrade Offer for VS 2005/2008 Standard Users: Soma blogs about a nice VS 2010 upgrade offer you can take advantage of if you have VS 2005 or VS 2008 Standard editions.  For $299 you can upgrade to VS 2010 Professional edition. Dependency Graphics: Jason Zander (who runs the VS team) has a nice blog post that covers the new dependency graph support within VS 2010.  This makes it easier to visualize the dependencies within your application.  Also check out this video here. Layer Validation: Jason Zander has a nice blog post that talks about the new layer validation features in VS 2010.  This enables you to enforce cleaner layering within your projects and solutions.  VS 2010 Profiler Blog: The VS 2010 Profiler Team has their own blog and on it you can find a bunch of nice posts from the last few months that talk about a lot of the new features coming with VS 2010’s Profiler support.  Some really nice features coming. Silverlight Silverlight 4 Training Course: Nice free set of training courses from Microsoft that can help bring you up to speed on all of the new Silverlight 4 features and how to build applications with them.  Updated and current with the recently released Silverlight 4 RC build and tools. Getting Started with Silverlight and Windows Phone 7 Development: Nice blog post by Tim Heuer that summarizes how to get started building Windows Phone 7 applications using Silverlight.  Also check out my blog post from last week on how to build a Windows Phone 7 Twitter application using Silverlight. A Guide to What Has Changed with the Silverlight 4 RC: Nice summary post by Tim Heuer that describes all of the things that have changed between the Silverlight 4 Beta and the Silverlight 4 RC. Path Based Layout - Part 1 and Part 2: Christian Schormann has a nice blog post about a really cool new feature in Expression Blend 4 and Silverlight 4 called Path Layout. Also check out Andy Beaulieu’s blog post on this. Hope this helps, Scott

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  • Creating an ASP.NET report using Visual Studio 2010 - Part 3

    - by rajbk
    We continue building our report in this three part series. Creating an ASP.NET report using Visual Studio 2010 - Part 1 Creating an ASP.NET report using Visual Studio 2010 - Part 2 Adding the ReportViewer control and filter drop downs. Open the source code for index.aspx and add a ScriptManager control. This control is required for the ReportViewer control. Add a DropDownList for the categories and suppliers. Add the ReportViewer control. The markup after these steps is shown below. <div> <asp:ScriptManager ID="smScriptManager" runat="server"> </asp:ScriptManager> <div id="searchFilter"> Filter by: Category : <asp:DropDownList ID="ddlCategories" runat="server" /> and Supplier : <asp:DropDownList ID="ddlSuppliers" runat="server" /> </div> <rsweb:ReportViewer ID="rvProducts" runat="server"> </rsweb:ReportViewer> </div> The design view for index.aspx is shown below. The dropdowns will display the categories and suppliers in the database. Changing the selection in the drop downs will cause the report to be filtered by the selections in the dropdowns. You will see how to do this in the next steps.   Attaching the RDLC to the ReportViewer control by clicking on the top right of the control, going to Report Viewer tasks and selecting Products.rdlc.   Resize the ReportViewer control by dragging at the bottom right corner. I set mine to 800px x 500px. You can also set this value in source view. Defining the data sources. We will now define the Data Source used to populate the report. Go back to the “ReportViewer Tasks” and select “Choose Data Sources” Select a “New data source..” Select “Object” and name your Data Source ID “odsProducts”   In the next screen, choose “ProductRepository” as your business object. Choose “GetProductsProjected” in the next screen.   The method requires a SupplierID and CategoryID. We will set these so that our data source gets the values from the drop down lists we defined earlier. Set the parameter source to be of type “Control” and set the ControlIDs to be ddlSuppliers and ddlCategories respectively. Your screen will look like this: We are now going to define the data source for our drop downs. Select the ddlCategory drop down and pick “Choose Data Source”. Pick “Object” and give it an id “odsCategories”   In the next screen, choose “ProductRepository” Select the GetCategories() method in the next screen.   Select “CategoryName” and “CategoryID” in the next screen. We are done defining the data source for the Category drop down. Perform the same steps for the Suppliers drop down.   Select each dropdown and set the AppendDataBoundItems to true and AutoPostback to true.     The AppendDataBoundItems is needed because we are going to insert an “All“ list item with a value of empty. Go to each drop down and add this list item markup as shown below> Finally, double click on each drop down in the designer and add the following code in the code behind. This along with the “Autopostback= true” attribute refreshes the report anytime a drop down is changed. protected void ddlCategories_SelectedIndexChanged(object sender, EventArgs e) { rvProducts.LocalReport.Refresh(); }   protected void ddlSuppliers_SelectedIndexChanged(object sender, EventArgs e) { rvProducts.LocalReport.Refresh(); } Compile your report and run the page. You should see the report rendered. Note that the tool bar in the ReportViewer control gives you a couple of options including the ability to export the data to Excel, PDF or word.   Conclusion Through this three part series, we did the following: Created a data layer for use by our RDLC. Created an RDLC using the report wizard and define a dataset for the report. Used the report design surface to design our report including adding a chart. Used the ReportViewer control to attach the RDLC. Connected our ReportWiewer to a data source and take parameter values from the drop downlists. Used AutoPostBack to refresh the reports when the dropdown selection was changed. RDLCs allow you to create interactive reports including drill downs and grouping. For even more advanced reports you can use Microsoft® SQL Server™ Reporting Services with RDLs. With RDLs, the report is rendered on the report server instead of the web server. Another nice thing about RDLs is that you can define a parameter list for the report and it gets rendered automatically for you. RDLCs and RDLs both have their advantages and its best to compare them and choose the right one for your requirements. Download VS2010 RTM Sample project NorthwindReports.zip   Alfred Borden: Are you watching closely?

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  • Introducing Data Annotations Extensions

    - by srkirkland
    Validation of user input is integral to building a modern web application, and ASP.NET MVC offers us a way to enforce business rules on both the client and server using Model Validation.  The recent release of ASP.NET MVC 3 has improved these offerings on the client side by introducing an unobtrusive validation library built on top of jquery.validation.  Out of the box MVC comes with support for Data Annotations (that is, System.ComponentModel.DataAnnotations) and can be extended to support other frameworks.  Data Annotations Validation is becoming more popular and is being baked in to many other Microsoft offerings, including Entity Framework, though with MVC it only contains four validators: Range, Required, StringLength and Regular Expression.  The Data Annotations Extensions project attempts to augment these validators with additional attributes while maintaining the clean integration Data Annotations provides. A Quick Word About Data Annotations Extensions The Data Annotations Extensions project can be found at http://dataannotationsextensions.org/, and currently provides 11 additional validation attributes (ex: Email, EqualTo, Min/Max) on top of Data Annotations’ original 4.  You can find a current list of the validation attributes on the afore mentioned website. The core library provides server-side validation attributes that can be used in any .NET 4.0 project (no MVC dependency). There is also an easily pluggable client-side validation library which can be used in ASP.NET MVC 3 projects using unobtrusive jquery validation (only MVC3 included javascript files are required). On to the Preview Let’s say you had the following “Customer” domain model (or view model, depending on your project structure) in an MVC 3 project: public class Customer { public string Email { get; set; } public int Age { get; set; } public string ProfilePictureLocation { get; set; } } .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; } When it comes time to create/edit this Customer, you will probably have a CustomerController and a simple form that just uses one of the Html.EditorFor() methods that the ASP.NET MVC tooling generates for you (or you can write yourself).  It should look something like this: With no validation, the customer can enter nonsense for an email address, and then can even report their age as a negative number!  With the built-in Data Annotations validation, I could do a bit better by adding a Range to the age, adding a RegularExpression for email (yuck!), and adding some required attributes.  However, I’d still be able to report my age as 10.75 years old, and my profile picture could still be any string.  Let’s use Data Annotations along with this project, Data Annotations Extensions, and see what we can get: public class Customer { [Email] [Required] public string Email { get; set; }   [Integer] [Min(1, ErrorMessage="Unless you are benjamin button you are lying.")] [Required] public int Age { get; set; }   [FileExtensions("png|jpg|jpeg|gif")] public string ProfilePictureLocation { get; set; } } .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; } Now let’s try to put in some invalid values and see what happens: That is very nice validation, all done on the client side (will also be validated on the server).  Also, the Customer class validation attributes are very easy to read and understand. Another bonus: Since Data Annotations Extensions can integrate with MVC 3’s unobtrusive validation, no additional scripts are required! Now that we’ve seen our target, let’s take a look at how to get there within a new MVC 3 project. Adding Data Annotations Extensions To Your Project First we will File->New Project and create an ASP.NET MVC 3 project.  I am going to use Razor for these examples, but any view engine can be used in practice.  Now go into the NuGet Extension Manager (right click on references and select add Library Package Reference) and search for “DataAnnotationsExtensions.”  You should see the following two packages: The first package is for server-side validation scenarios, but since we are using MVC 3 and would like comprehensive sever and client validation support, click on the DataAnnotationsExtensions.MVC3 project and then click Install.  This will install the Data Annotations Extensions server and client validation DLLs along with David Ebbo’s web activator (which enables the validation attributes to be registered with MVC 3). Now that Data Annotations Extensions is installed you have all you need to start doing advanced model validation.  If you are already using Data Annotations in your project, just making use of the additional validation attributes will provide client and server validation automatically.  However, assuming you are starting with a blank project I’ll walk you through setting up a controller and model to test with. Creating Your Model In the Models folder, create a new User.cs file with a User class that you can use as a model.  To start with, I’ll use the following class: public class User { public string Email { get; set; } public string Password { get; set; } public string PasswordConfirm { get; set; } public string HomePage { get; set; } public int Age { get; set; } } Next, create a simple controller with at least a Create method, and then a matching Create view (note, you can do all of this via the MVC built-in tooling).  Your files will look something like this: UserController.cs: public class UserController : Controller { public ActionResult Create() { return View(new User()); }   [HttpPost] public ActionResult Create(User user) { if (!ModelState.IsValid) { return View(user); }   return Content("User valid!"); } } .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; } Create.cshtml: @model NuGetValidationTester.Models.User   @{ ViewBag.Title = "Create"; }   <h2>Create</h2>   <script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>   @using (Html.BeginForm()) { @Html.ValidationSummary(true) <fieldset> <legend>User</legend> @Html.EditorForModel() <p> <input type="submit" value="Create" /> </p> </fieldset> } .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; } In the Create.cshtml view, note that we are referencing jquery validation and jquery unobtrusive (jquery is referenced in the layout page).  These MVC 3 included scripts are the only ones you need to enjoy both the basic Data Annotations validation as well as the validation additions available in Data Annotations Extensions.  These references are added by default when you use the MVC 3 “Add View” dialog on a modification template type. Now when we go to /User/Create we should see a form for editing a User Since we haven’t yet added any validation attributes, this form is valid as shown (including no password, email and an age of 0).  With the built-in Data Annotations attributes we can make some of the fields required, and we could use a range validator of maybe 1 to 110 on Age (of course we don’t want to leave out supercentenarians) but let’s go further and validate our input comprehensively using Data Annotations Extensions.  The new and improved User.cs model class. { [Required] [Email] public string Email { get; set; }   [Required] public string Password { get; set; }   [Required] [EqualTo("Password")] public string PasswordConfirm { get; set; }   [Url] public string HomePage { get; set; }   [Integer] [Min(1)] public int Age { get; set; } } .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; } Now let’s re-run our form and try to use some invalid values: All of the validation errors you see above occurred on the client, without ever even hitting submit.  The validation is also checked on the server, which is a good practice since client validation is easily bypassed. That’s all you need to do to start a new project and include Data Annotations Extensions, and of course you can integrate it into an existing project just as easily. Nitpickers Corner ASP.NET MVC 3 futures defines four new data annotations attributes which this project has as well: CreditCard, Email, Url and EqualTo.  Unfortunately referencing MVC 3 futures necessitates taking an dependency on MVC 3 in your model layer, which may be unadvisable in a multi-tiered project.  Data Annotations Extensions keeps the server and client side libraries separate so using the project’s validation attributes don’t require you to take any additional dependencies in your model layer which still allowing for the rich client validation experience if you are using MVC 3. Custom Error Message and Globalization: Since the Data Annotations Extensions are build on top of Data Annotations, you have the ability to define your own static error messages and even to use resource files for very customizable error messages. Available Validators: Please see the project site at http://dataannotationsextensions.org/ for an up-to-date list of the new validators included in this project.  As of this post, the following validators are available: CreditCard Date Digits Email EqualTo FileExtensions Integer Max Min Numeric Url Conclusion Hopefully I’ve illustrated how easy it is to add server and client validation to your MVC 3 projects, and how to easily you can extend the available validation options to meet real world needs. The Data Annotations Extensions project is fully open source under the BSD license.  Any feedback would be greatly appreciated.  More information than you require, along with links to the source code, is available at http://dataannotationsextensions.org/. Enjoy!

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  • Entity Association Mapping with Code First Part 1 : Mapping Complex Types

    - by mortezam
    Last week the CTP5 build of the new Entity Framework Code First has been released by data team at Microsoft. Entity Framework Code-First provides a pretty powerful code-centric way to work with the databases. When it comes to associations, it brings ultimate flexibility. I’m a big fan of the EF Code First approach and am planning to explain association mapping with code first in a series of blog posts and this one is dedicated to Complex Types. If you are new to Code First approach, you can find a great walkthrough here. In order to build a solid foundation for our discussion, we will start by learning about some of the core concepts around the relationship mapping.   What is Mapping?Mapping is the act of determining how objects and their relationships are persisted in permanent data storage, in our case, relational databases. What is Relationship mapping?A mapping that describes how to persist a relationship (association, aggregation, or composition) between two or more objects. Types of RelationshipsThere are two categories of object relationships that we need to be concerned with when mapping associations. The first category is based on multiplicity and it includes three types: One-to-one relationships: This is a relationship where the maximums of each of its multiplicities is one. One-to-many relationships: Also known as a many-to-one relationship, this occurs when the maximum of one multiplicity is one and the other is greater than one. Many-to-many relationships: This is a relationship where the maximum of both multiplicities is greater than one. The second category is based on directionality and it contains two types: Uni-directional relationships: when an object knows about the object(s) it is related to but the other object(s) do not know of the original object. To put this in EF terminology, when a navigation property exists only on one of the association ends and not on the both. Bi-directional relationships: When the objects on both end of the relationship know of each other (i.e. a navigation property defined on both ends). How Object Relationships Are Implemented in POCO domain models?When the multiplicity is one (e.g. 0..1 or 1) the relationship is implemented by defining a navigation property that reference the other object (e.g. an Address property on User class). When the multiplicity is many (e.g. 0..*, 1..*) the relationship is implemented via an ICollection of the type of other object. How Relational Database Relationships Are Implemented? Relationships in relational databases are maintained through the use of Foreign Keys. A foreign key is a data attribute(s) that appears in one table and must be the primary key or other candidate key in another table. With a one-to-one relationship the foreign key needs to be implemented by one of the tables. To implement a one-to-many relationship we implement a foreign key from the “one table” to the “many table”. We could also choose to implement a one-to-many relationship via an associative table (aka Join table), effectively making it a many-to-many relationship. Introducing the ModelNow, let's review the model that we are going to use in order to implement Complex Type with Code First. It's a simple object model which consist of two classes: User and Address. Each user could have one billing address. The Address information of a User is modeled as a separate class as you can see in the UML model below: In object-modeling terms, this association is a kind of aggregation—a part-of relationship. Aggregation is a strong form of association; it has some additional semantics with regard to the lifecycle of objects. In this case, we have an even stronger form, composition, where the lifecycle of the part is fully dependent upon the lifecycle of the whole. Fine-grained domain models The motivation behind this design was to achieve Fine-grained domain models. In crude terms, fine-grained means “more classes than tables”. For example, a user may have both a billing address and a home address. In the database, you may have a single User table with the columns BillingStreet, BillingCity, and BillingPostalCode along with HomeStreet, HomeCity, and HomePostalCode. There are good reasons to use this somewhat denormalized relational model (performance, for one). In our object model, we can use the same approach, representing the two addresses as six string-valued properties of the User class. But it’s much better to model this using an Address class, where User has the BillingAddress and HomeAddress properties. This object model achieves improved cohesion and greater code reuse and is more understandable. Complex Types: Splitting a Table Across Multiple Types Back to our model, there is no difference between this composition and other weaker styles of association when it comes to the actual C# implementation. But in the context of ORM, there is a big difference: A composed class is often a candidate Complex Type. But C# has no concept of composition—a class or property can’t be marked as a composition. The only difference is the object identifier: a complex type has no individual identity (i.e. no AddressId defined on Address class) which make sense because when it comes to the database everything is going to be saved into one single table. How to implement a Complex Types with Code First Code First has a concept of Complex Type Discovery that works based on a set of Conventions. The convention is that if Code First discovers a class where a primary key cannot be inferred, and no primary key is registered through Data Annotations or the fluent API, then the type will be automatically registered as a complex type. Complex type detection also requires that the type does not have properties that reference entity types (i.e. all the properties must be scalar types) and is not referenced from a collection property on another type. Here is the implementation: public class User{    public int UserId { get; set; }    public string FirstName { get; set; }    public string LastName { get; set; }    public string Username { get; set; }    public Address Address { get; set; }} public class Address {     public string Street { get; set; }     public string City { get; set; }            public string PostalCode { get; set; }        }public class EntityMappingContext : DbContext {     public DbSet<User> Users { get; set; }        } With code first, this is all of the code we need to write to create a complex type, we do not need to configure any additional database schema mapping information through Data Annotations or the fluent API. Database SchemaThe mapping result for this object model is as follows: Limitations of this mappingThere are two important limitations to classes mapped as Complex Types: Shared references is not possible: The Address Complex Type doesn’t have its own database identity (primary key) and so can’t be referred to by any object other than the containing instance of User (e.g. a Shipping class that also needs to reference the same User Address). No elegant way to represent a null reference There is no elegant way to represent a null reference to an Address. When reading from database, EF Code First always initialize Address object even if values in all mapped columns of the complex type are null. This means that if you store a complex type object with all null property values, EF Code First returns a initialized complex type when the owning entity object is retrieved from the database. SummaryIn this post we learned about fine-grained domain models which complex type is just one example of it. Fine-grained is fully supported by EF Code First and is known as the most important requirement for a rich domain model. Complex type is usually the simplest way to represent one-to-one relationships and because the lifecycle is almost always dependent in such a case, it’s either an aggregation or a composition in UML. In the next posts we will revisit the same domain model and will learn about other ways to map a one-to-one association that does not have the limitations of the complex types. References ADO.NET team blog Mapping Objects to Relational Databases Java Persistence with Hibernate

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  • Data caching in ASP.Net applications

    - by nikolaosk
    In this post I will continue my series of posts on caching. You can read my other post in Output caching here .You can read on how to cache a page depending on the user's browser language. Output caching has its place as a caching mechanism. But right now I will focus on data caching .The advantages of data caching are well known but I will highlight the main points. We have improvements in response times We have reduced database round trips We have different levels of caching and it is up to us...(read more)

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