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  • How do I make this Query against EF Efficient?

    - by dudeNumber4
    Using EF4. Assume I have this: IQueryable<ParentEntity> qry = myRepository.GetParentEntities(); Int32 n = 1; What I want to do is this, but EF can't compare against null. qry.Where( parent => parent.Children.Where( child => child.IntCol == n ) != null ) What works is this, but the SQL it produces (as you would imagine) is pretty inefficient: qry.Where( parent => parent.Children.Where( child => child.IntCol == n ).FirstOrDefault().IntCol == n ) How can I do something like the first comparison to null that won't be generating nested queries and so forth?

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  • Missing something with Entity Framework for .NET 3.5?

    - by AC
    Is it not possible to have EF create the necessary entities when I have two related tables linked with a FK in .NET3.5SP1? I see where the checkbox to support this is disabled but it is available in .NET4. I've got a DB that has only tables with relationships in it. I need to build a Silverlight app (SL4) that allows management of the data within this app. I can't use .NET4 on the server... only .NET3.5SP1 so FK relationship bit in EF4 isn't available to me. Looking to avoid building as much of the plumbing to get back to the DB from the SL4 app as possible...

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  • Entity Framework 5 upgrade from 4

    - by user1714591
    I'm having an issue with the Where clause in a search, in my original version EF4 I could add a Where clause with 2 parameters, the where clause (string predicate) and a ObjectParameter list such as var query = context.entities.Where(WhereClause.ToString(), Params.ToArray()); since my upgrade to EF5 I don't seem to have that option am I missing something? This was originally used to build dynamic where clause such as "it.entity_id = @entity_id" then holding the variable value in the ObjectParameter. I'm hoping I don't have to rewrite all the searches that have been built out this way, so any assistance would be greatly appreciated. Cheers

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  • Saving a modified object from ASP.NET MVC View Using Entity-Franework 4

    - by Dani
    I retrieve an object graph from DB using EF4. The context is closed as soon as the data retrieve and the data passes to the controller, and then to the view. in the view the data is modified, and then the controller gets it back. From the controller I run Repository.Update(MyEmp); and in my repository the code goes: using (var context = new mydb()) { if (myEmp.ID != 0) // Checking if it's modified or new { context.Emp.Attach(MyEmp); int result = context.SaveChanges(); return myEmp.ID; } } The problem - once attached, the object entityState goes to unchanged, and not modified, and of course - nothing is saved to the database. What am I doing wrong ?

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  • EF Stored Procedure Complex Type

    - by Web Dev
    I am using EF4. I am somewhat confused on on the Entity Framework Complex name. When I go to Functional Import of a Stored Procedure name and it ask me to type in the Complex name, is that supposed to be the name of of a class that can handle that output. For examle, say if my stored procedure returns FirstName, LastName. Is the Complex name supposed to be a class that can handle that output in this case PersonName? public class PersonName { public string FirstName {get; set;} public string LastName {get;set} }

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  • .Net Application & Database Modularity/Reuse

    - by Martaver
    I'm looking for some guidance on how to architect an app with regards to modularity, separation of concerns and re-usability. I'm working on an application (ASP.Net, C#) that has distinctly generic chunks of functionality, that I'd love to be able to lift out, all layers, into re-usable components. This means the module handles the database schema, data access, API, everything so that the next time I want to use it I can just register the module and hook into it. Developing modules of re-usable functionality is a no-brainer, but what is really confusing me is what to do when it comes to handling a core re-usable database schema that serves the module's functionality. In an ideal world, I would register a module and it would ensure that the associated database schema exists in the DB. I would code on the assumption that the tables exist, calling the module's functionality through the DLL, agnostic of the database layer. Kind of like Enterprise Library's Caching/Logging Application Block, which can create a DB schema in the target DB to use as a data store. My Questions is: What do you think is the best way to achieve this, firstly, in terms design architecture, and secondly solution structure. What patterns/frameworks do you know that exist & support this kind of thing? My thoughts so far: I mostly use Entity Framework and SQL Server DB Projects. I thought about a 'black box' approach to modules of functionality. I could use use a code-first approach in EF4, and use the ObjectContext to create a database when the module is initialized. However this means that all of the entities that my module encapsulates would be disconnected from the rest of the application because they belonged to an abstracted ObjectContext. Further - Creating appropriate indexes and references between domain entities and the module's entities would be impossible to do practically. I've thought of adopting Enterprise Library and creating my own Application Blocks. I'm not sure how this would play nice with Entity Framework (if at all) though. I like the idea of building on proven patterns & practices to encapsulate established, reusable functionality. I thought of abandoning Entity Framework for the Module, and just creating a separate DB schema for the module with its own set of stored procedures & ADO.Net. Then deploying the script at run-time if interrogation shows that it doesn't exist. But once again, for application developing outside of the application, I would want to use Entity Framework and I would have to use the module separately, disconnected from the domain ObjectContext. Has anyone had experience developing these sorts of full-stack modules? What advice can you offer? Am I biting off more than I can chew?

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  • Am I just not understanding TDD unit testing (Asp.Net MVC project)?

    - by KallDrexx
    I am trying to figure out how to correctly and efficiently unit test my Asp.net MVC project. When I started on this project I bought the Pro ASP.Net MVC, and with that book I learned about TDD and unit testing. After seeing the examples, and the fact that I work as a software engineer in QA in my current company, I was amazed at how awesome TDD seemed to be. So I started working on my project and went gun-ho writing unit tests for my database layer, business layer, and controllers. Everything got a unit test prior to implementation. At first I thought it was awesome, but then things started to go downhill. Here are the issues I started encountering: I ended up writing application code in order to make it possible for unit tests to be performed. I don't mean this in a good way as in my code was broken and I had to fix it so the unit test pass. I mean that abstracting out the database to a mock database is impossible due to the use of linq for data retrieval (using the generic repository pattern). The reason is that with linq-sql or linq-entities you can do joins just by doing: var objs = select p from _container.Projects select p.Objects; However, if you mock the database layer out, in order to have that linq pass the unit test you must change the linq to be var objs = select p from _container.Projects join o in _container.Objects on o.ProjectId equals p.Id select o; Not only does this mean you are changing your application logic just so you can unit test it, but you are making your code less efficient for the sole purpose of testability, and getting rid of a lot of advantages using an ORM has in the first place. Furthermore, since a lot of the IDs for my models are database generated, I proved to have to write additional code to handle the non-database tests since IDs were never generated and I had to still handle those cases for the unit tests to pass, yet they would never occur in real scenarios. Thus I ended up throwing out my database unit testing. Writing unit tests for controllers was easy as long as I was returning views. However, the major part of my application (and the one that would benefit most from unit testing) is a complicated ajax web application. For various reasons I decided to change the app from returning views to returning JSON with the data I needed. After this occurred my unit tests became extremely painful to write, as I have not found any good way to write unit tests for non-trivial json. After pounding my head and wasting a ton of time trying to find a good way to unit test the JSON, I gave up and deleted all of my controller unit tests (all controller actions are focused on this part of the app so far). So finally I was left with testing the Service layer (BLL). Right now I am using EF4, however I had this issue with linq-sql as well. I chose to do the EF4 model-first approach because to me, it makes sense to do it that way (define my business objects and let the framework figure out how to translate it into the sql backend). This was fine at the beginning but now it is becoming cumbersome due to relationships. For example say I have Project, User, and Object entities. One Object must be associated to a project, and a project must be associated to a user. This is not only a database specific rule, these are my business rules as well. However, say I want to do a unit test that I am able to save an object (for a simple example). I now have to do the following code just to make sure the save worked: User usr = new User { Name = "Me" }; _userService.SaveUser(usr); Project prj = new Project { Name = "Test Project", Owner = usr }; _projectService.SaveProject(prj); Object obj = new Object { Name = "Test Object" }; _objectService.SaveObject(obj); // Perform verifications There are many issues with having to do all this just to perform one unit test. There are several issues with this. For starters, if I add a new dependency, such as all projects must belong to a category, I must go into EVERY single unit test that references a project, add code to save the category then add code to add the category to the project. This can be a HUGE effort down the road for a very simple business logic change, and yet almost none of the unit tests I will be modifying for this requirement are actually meant to test that feature/requirement. If I then add verifications to my SaveProject method, so that projects cannot be saved unless they have a name with at least 5 characters, I then have to go through every Object and Project unit test to make sure that the new requirement doesn't make any unrelated unit tests fail. If there is an issue in the UserService.SaveUser() method it will cause all project, and object unit tests to fail and it the cause won't be immediately noticeable without having to dig through the exceptions. Thus I have removed all service layer unit tests from my project. I could go on and on, but so far I have not seen any way for unit testing to actually help me and not get in my way. I can see specific cases where I can, and probably will, implement unit tests, such as making sure my data verification methods work correctly, but those cases are few and far between. Some of my issues can probably be mitigated but not without adding extra layers to my application, and thus making more points of failure just so I can unit test. Thus I have no unit tests left in my code. Luckily I heavily use source control so I can get them back if I need but I just don't see the point. Everywhere on the internet I see people talking about how great TDD unit tests are, and I'm not just talking about the fanatical people. The few people who dismiss TDD/Unit tests give bad arguments claiming they are more efficient debugging by hand through the IDE, or that their coding skills are amazing that they don't need it. I recognize that both of those arguments are utter bullocks, especially for a project that needs to be maintainable by multiple developers, but any valid rebuttals to TDD seem to be few and far between. So the point of this post is to ask, am I just not understanding how to use TDD and automatic unit tests?

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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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  • Extracting the Date from a DateTime in Entity Framework 4 and LINQ

    - by Ken Cox [MVP]
    In my current ASP.NET 4 project, I’m displaying dates in a GridDateTimeColumn of Telerik’s ASP.NET Radgrid control. I don’t care about the time stuff, so my DataFormatString shows only the date bits: <telerik:GridDateTimeColumn FilterControlWidth="100px"   DataField="DateCreated" HeaderText="Created"    SortExpression="DateCreated" ReadOnly="True"    UniqueName="DateCreated" PickerType="DatePicker"    DataFormatString="{0:dd MMM yy}"> My problem was that I couldn’t get the built-in column filtering (it uses Telerik’s DatePicker control) to behave.  The DatePicker assumes that the time is 00:00:00 but the data would have times like 09:22:21. So, when you select a date and apply the EqualTo filter, you get no results. You would get results if all the time portions were 00:00:00. In essence, I wanted my Entity Framework query to give the DatePicker what it wanted… a Date without the Time portion. Fortunately, EF4 provides the TruncateTime  function. After you include Imports System.Data.Objects.EntityFunctions You’ll find that your EF queries will accept the TruncateTime function. Here’s my routine: Protected Sub RadGrid1_NeedDataSource _     (ByVal source As Object, _      ByVal e As Telerik.Web.UI.GridNeedDataSourceEventArgs) _     Handles RadGrid1.NeedDataSource     Dim ent As New OfficeBookDBEntities1     Dim TopBOMs = From t In ent.TopBom, i In ent.Items _                   Where t.BusActivityID = busActivityID _       And i.BusActivityID And t.ItemID = i.RecordID _       Order By t.DateUpdated Descending _       Select New With {.TopBomID = t.TopBomID, .ItemID = t.ItemID, _                        .PartNumber = i.PartNumber, _                        .Description = i.Description, .Notes = t.Notes, _                        .DateCreated = TruncateTime(t.DateCreated), _                        .DateUpdated = TruncateTime(t.DateUpdated)}     RadGrid1.DataSource = TopBOMs End Sub Now when I select March 14, 2011 on the DatePicker, the filter doesn’t stumble on time values that don’t make sense. Full Disclosure: Telerik gives me (and other developer MVPs) free copies of their suite.

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  • RC of Entity Framework 4.1 (which includes EF Code First)

    - by ScottGu
    Last week the data team shipped the Release Candidate of Entity Framework 4.1.  You can learn more about it and download it here. EF 4.1 includes the new “EF Code First” option that I’ve blogged about several times in the past.  EF Code First provides a really elegant and clean way to work with data, and enables you to do so without requiring a designer or XML mapping file.  Below are links to some tutorials I’ve written in the past about it: Code First Development with Entity Framework 4.x EF Code First: Custom Database Schema Mapping Using EF Code First with an Existing Database The above tutorials were written against the CTP4 release of EF Code First (and so some APIs might be a little different) – but the concepts and scenarios outlined in them are the same as with the RC. Go Live License Last week’s EF 4.1 RC ships with a “go live” license that enables you to use it in production environments.  The final release of EF 4.1 will ship within the next 4 weeks and will be 100% API compatible with the RC release. Improvements with the RC The RC includes several improvements and enhancements.  The EF team has a good blog post summarizing the RC changes.  Scott Hanselman also has a nice video interview with the data team that talks more about the release. One of my favorite improvements introduced with last week’s RC is its support for medium trust security.  This enables you to use EF 4.1 (and code-first) within low-cost ASP.NET shared hosting web environments – without requiring a hoster to install anything to use it. EF 4.1 also now supports validation with not only code-first scenarios, but also model-first and database-first workflows.  Upgrading from previous releases The RC does include a few API tweaks and changes from the prior CTP builds.  Read the release notes that come with the release to get a more detailed listing of the changes. John Papa also has an excellent Upgrading to EF 4.1 RC blog post that describes the steps he took when upgrading a large project he wrote with the previous CTP5 release.  The work to upgrade is pretty straight forward and easy – use his write-up as a guide on how to quickly update projects of your own. NuGet Package Rename One of the changes that the data team made between the CTP5 and RC releases was to rename the NuGet package name from “EFCodeFirst” to “EntityFramework”. They decided to make this change since the EF 4.1 release now includes several additions above and beyond just code first. If you already have installed the “EFCodeFirst” NuGet package, you’ll want to uninstall it and then install the new “EntityFramework” NuGet package.  John Papa’s blog post details the exact steps on how to do this (it only takes ~20 seconds to do this). More EF Tutorials Julie Lerman has created some nice whitepapers and tutorials for MSDN that show using the new EF4 and EF 4.1 feature set. Click here to find links to read and watch them. Summary I’m really excited about the EF 4.1 release that will be shipping next month.  It significantly improves the Entity Framework, and makes it even easier and cleaner to work with data inside of .NET.  You can take advantage of it within all ASP.NET projects (including both Web Forms and MVC), within client projects using Windows Forms and WPF, and within other project types like WCF, Console and Services.  You can use NuGet to easily install it within all of them. Hope this helps, Scott P.S. I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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  • A list of Entity Framework providers for various databases

    - by Robert Koritnik
    Which providers are there and your experience using them I would like to know about all possible native .net Framework Entity Framework providers that are out there as well as their limitations compared to the default Linq2Entities (from MS for MS SQL). If there are more for the same database even better. Tell me and I'll be updating this post with this list. Feel free to add additional providers directly into this post or provide an answer and others (including me) will add it to the list. Entity Framework 1 Microsoft SQL Server Standard/Enterprise/Express Linq 2 Entities - Microsoft SQL Server connector DataDirect ADO.NET Data Providers Microsoft SQL Server CE (Compact Edition) Any provider? MySQL MySQL Connector (since version 6.0) - I've read about issues when using Skip(), Take() and Sort() in the same expression tree - everyone welcome to input their experience/knowledge regarding this. (NOTE: MySQL Connector/NET Visual Studio Integration is not supported in the Express Editions of Visual Studio, meaning you won't be able to view MySQL databases in the Database explorer window or add a MySQL data source via Visual Studio wizard dialog boxes. Some users may find that this limits their ability to use Entity Framework and MySQL within Visual Studio Express). Devart dotConnect for MySQL - similar issues to MySql's connector as I've read and both try to blame MS for it [these issues are supposed to be solved] SQLite Devart dotConnect for SQLite System.Data.SQLite PostgreSQL Devart dotConnect for PostgreSQL Npgsql Oracle Devart dotConnect for Oracle Sample Entity Framework Provider for Oracle - community effort project DataDirect ADO.NET Data Providers DB2 IBM Data Server Provider has EF support. Here are some limitations. DataDirect ADO.NET Data Providers Sybase Sybase iAnywhere DataDirect ADO.NET Data Providers Informix IBM Data Server Provider supports Informix Firebird ADO.NET Data Provider with EF support Provider Wrappers Tracing and Caching Providers for EF Entity Framework 4 (beta) Microsoft SQL Server Microsoft's Linq to Entities 4 - shipped with .net 4.0 and Visual Studio 2010; so far the only provider for EF4 MySQL Devart dotConnect for MySQL SQLite Devart dotConnect for SQLite PostgreSQL Devart dotConnect for PostgreSQL Oracle Devart dotConnect for Oracle

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  • Defining reliable SIlverlight 4 architecture

    - by doteneter
    Hello everybody, It's my first question on SO. I know that there were many topics on Silverlight and architecture but didn't find answers that satisfies me. I'm ASP.NET MVC developer and are used to work on architectures built with the best practices (loose coupling with DI, etc.) Now I'm faced to the new Silverlight 4 project and would like to be sure I'm doing the best choices as I'm not experienced. Main features required by the applications are as follows : use existing SQL Server Database but with possibility to move to the cloud. using EF4 for the data acess with SQL Server. exitensibility : adding new modules without changing the main host. loose coupling. I was looking at different webcasts (Taulty, etc.), blogs about Silverlight and came up with the following architecture. EF 4 for data access (as specified with the requirements) WCF RIA Services for mid-tiers controling access to data for queries and enabling end-to-end support for data validation, authentication and roles. MEF Support for enabling modules. Unity 2.0 for DI. The problem is that I don't know how to define a reliable architecture where all these elements play well together. Should I use a framework instead like Prism or Caliburn? But for now I'm not sure what scenarios they support. What's the best usages for Unity in Silverlight ? I used to use IoC in ASP.NET MVC for loos coupling and other things like interception for audit logging. It seems that for Silverlight Unity doesn't support Interception. I would like to use it to enable loose coupling and to enable to move to the cloud if needed. Thanks in advance for your help.

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  • Do I really need an ORM?

    - by alchemical
    We're about to begin development on a mid-size ASP.Net MVC 2 web site. For a typical page, we grab data and throw it up on the web page, i.e. there is not much pre-processing of the data before it is sent to the UI. We're now making the decision whether or not to use an ORM and if yes, which one. We had been looking at EF2 AKA EF4 (ASP.Net Entity Framework in VS 2010) as one possibility. However, I'm thinking a simple solution in this case may be just to use datatables. The reason being that we don't plan to move the data around or process it a lot once we fetch it, so I'm not sure there is that much value in having strongly-typed objects as DTOs. Also, this way we avoid mapping altogether, thereby I think simplifying the code and allowing for faster development. I should mention budget is an issue on this project, as well as speed of execution. We are striving for simplicity anywhere we can, both to keep the budget smaller, the schedule shorter, and performance fast. We haven't fully decided this yet, but are currently leaning towards no ORM. Will we be OK with the no ORM approach or is an ORM worth it?

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  • Validation in n-tier asp.net mvc applications

    - by sTodorov
    Dear Stack Overflow gurus, I am looking for some practical/theoretical information regarding best practices for validation in asp.net mvc n-tier applications. I am working on a .Net application divided into the following layers: UI - Mvc3 BLL layer - all business rules. Decoupled from data access and UI layers through interfaces DAL layer - Data access with the repository pattern, EF4 and pocos Now, I am looking for a nice, clean and transparent way to specify my validation rules. Here are some thoughts on the matter so far: UI validation should only be responsible for user input and its validity. BLL validation should be handling the validity of the data regarding the application business rules. My main concern is how to bind the BLL and UI validation in the most efficient way. One think I am would like to avoid is having the UI check in a collection of validation and adding manually errors to the ModelState. Furthermore, I do not want to pass the ModelState to the BLL to be populated in there. I will appreciate any thoughts on the matter. P.S. Should this question be marked as a discussion ?

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  • Entity Framework - Foreign key constraints not added for inherited entity

    - by Tri Q
    Hello, It appears to me that a strange phenomenon is occurring with inherited entities (TPT) in EF4. I have three entities. 1. Asset 2. Property 3. Activity Property is a derived-type of Asset. Property has many activities (many-to-many) When modeling this in my EDMX, everything seems fine until I try to insert a new Property into the database. If the property does not contain any Activity, it works, but all hell breaks loose when I add some new activities to the new Property. As it turns out after 2 days of crawling the web and fiddling around, I noticed that in the EF store (SSDL) some of the constraints between entities were not picked up during the update process. Property_Activity table which links properties and activities show only one constraint FK_Property_Activity_Activity but FK_Property_Activity_Property was missing. I knew this is an Entity Framework anomoly because when I switched the relationship in the database to: Asset <-- Asset_Activity <-- Activity After an update, all foreign key constraints are picked up and the save is successful, with or without activities in the new property. Is this intended or a bug in EF? How do I get around this problem? Should I abandon inheritance altogether?

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  • Idiomatic default sort using WCF RIA, Entity Framework 4, Silverlight 4?

    - by Duncan Bayne
    I've got two Silverlight 4.0 ComboBoxes; the second displays the children of the entity selected in the first: <ComboBox Name="cmbThings" ItemsSource="{Binding Path=Things,Mode=TwoWay}" DisplayMemberPath="Name" SelectionChanged="CmbThingsSelectionChanged" /> <ComboBox Name="cmbChildThings" ItemsSource="{Binding Path=SelectedThing.ChildThings,Mode=TwoWay}" DisplayMemberPath="Name" /> The code behind the view provides a (simple, hacky) way to databind those ComboBoxes, by loading Entity Framework 4.0 entities through a WCF RIA service: public EntitySet<Thing> Things { get; private set; } public Thing SelectedThing { get; private set; } protected override void OnNavigatedTo(NavigationEventArgs e) { var context = new SortingDomainContext(); context.Load(context.GetThingsQuery()); context.Load(context.GetChildThingsQuery()); Things = context.Things; DataContext = this; } private void CmbThingsSelectionChanged(object sender, SelectionChangedEventArgs e) { SelectedThing = (Thing) cmbThings.SelectedItem; if (PropertyChanged != null) { PropertyChanged.Invoke(this, new PropertyChangedEventArgs("SelectedThing")); } } public event PropertyChangedEventHandler PropertyChanged; What I'd like to do is have both combo boxes sort their contents alphabetically, and I'd like to specify that behaviour in the XAML if at all possible. Could someone please tell me what is the idiomatic way of doing this with the SL4 / EF4 / WCF RIA technology stack?

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  • Entity Framework 4 overwrite Equals and GetHashCode of an own class property

    - by Zhok
    Hi, I’m using Visual Studio 2010 with .NET 4 and Entity Framework 4. I’m working with POCO Classes and not the EF4 Generator. I need to overwrite the Equals() and GetHashCode() Method but that doesn’t really work. Thought it’s something everybody does but I don’t find anything about the problem Online. When I write my own Classes and Equals Method, I use Equals() of property’s, witch need to be loaded by EF to be filled. Like this: public class Item { public virtual int Id { get; set; } public virtual String Name { get; set; } public virtual List<UserItem> UserItems { get; set; } public virtual ItemType ItemType { get; set; } public override bool Equals(object obj) { Item item = obj as Item; if (obj == null) { return false; } return item.Name.Equals(this.Name) && item.ItemType.Equals(this.ItemType); } public override int GetHashCode() { return this.Name.GetHashCode() ^ this.ItemType.GetHashCode(); } } That Code doesn’t work, the problems are in Equals and GetHashCode where I try to get HashCode or Equal from “ItemType” . Every time I get a NullRefernceException if I try to get data by Linq2Entites. A dirty way to fix it, is to capture the NullReferenceException and return false (by Equals) and return base.GetHashCode() (by GethashCode) but I hope there is a better way to fix this problem. I’ve wrote a little test project, with SQL Script for the DB and POCO Domain, EDMX File and Console Test Main Method. You can download it here: Download

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  • entity framework vNext wish list

    - by Fred Yang
    I have been intensively studying and use ef4 in my project. I do feel the improvement that it has over version 1. But I found that I have something I cannot get around easily. Here is a list I want it to be better in ef vNext. the model designer should allow multiple view of the same model, so that I don't need cram all my entity into a single view. respect user's manual edit of edmx. Currently, the some database view object simply can not be imported to the model because the designer "smartly" think that the view does not have a primary key, so that I have to manually edit the edmx to correct designer's behavior. But in the next "update from database" task, designer will revert my customization. For now, I simply fallback to manually edit the edmx file at all, or I have to use compare tool to keep the new update, and rollback and put the new update into my old edmx file manually. Designer should be improved to allow default behavior and user's manual control. I want control not to let the designer refresh the change of imported object. support user defined table function. linq is about Composability, stored proc dos not support composability. I wish I could use user defined table function which support this. What are you wishes for EF vNext?

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  • Quick MVC2 checkbox question

    - by kevinmajor1
    In order to get my EF4 EntityCollection to bind with check box values, I have to manually create the check boxes in a loop like so: <p> <%: Html.Label("Platforms") %><br /> <% for(var i = 0; i < Model.AllPlatforms.Count; ++i) { %> <%: Model.AllPlatforms[i].Platform.Name %> <input type="checkbox" name="PlatformIDs" value="<%: Model.AllPlatforms[i].Platform.PlatformID %>" /><br /> <% } %> </p> It works, but it doesn't automatically populate the group of check boxes with existing values when I'm editing a model entity. Can I fudge it with something like? <p> <%: Html.Label("Platforms") %><br /> <% for(var i = 0; i < Model.AllPlatforms.Count; ++i) { %> <%: Model.AllPlatforms[i].Platform.Name %> <input type="checkbox" name="PlatformIDs" value="<%: Model.AllPlatforms[i].Platform.PlatformID %>" checked=<%: Model.GameData.Platforms.Any(p => PlatformID == i) ? "true" : "false" %> /><br /> <% } %> </p> I figure there has to be something along those lines which will work, and am just wondering if I'm on the right track. EDIT: I'm purposely staying away from MVC's check box HTML helper methods as they're too inflexible for my needs. My check boxes use integers as their values by design.

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  • EF 4 Self Tracking Entities does not work as expected.

    - by ashraf
    I am using EF4 Self Tracking Entities (VS2010 Beta 2 CTP 2 plus new T4 generator). But when I try to update entity information it does not update to database as expected. I setup 2 service calls. one for GetResource(int id) which return a resource object. the second call is SaveResource(Resource res); here is the code. public Resource GetResource(int id) { using (var dc = new MyEntities()) { return dc.Resources.Where(d => d.ResourceId == id).SingleOrDefault(); } } public void SaveResource(Resource res) { using (var dc = new MyEntities()) { dc.Resources.ApplyChanges(res); dc.SaveChanges(); // Nothing save to database. } } //Windows Console Client Calls var res = service.GetResource(1); res.Description = "New Change"; // Not updating... service.SaveResource(res); // does not change anything. It seems to me that ChangeTracker.State is always show as "Unchanged". anything wrong in this code?

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  • The perfect web UI framework (with Microsoft stack?) - architecture question?

    - by Igorek
    I'm looking for suggestions for the following issue, and I realize there is really not going to be a perfect answer to my question: I have a UI built in WinForms.NET (v4.0 framework) with WCF back-end and EF4 model objects, that I am looking to port to the web. UI is not huge and is not super complex and is structured well. But it is not a super simple system either. I am looking to pick a technology stack for the web-frontend that will target desktop & partially mobile platforms, provide a good development platform to build on, and facilitate code reuse across UI and back-end tiers... I would rather avoid: custom coding of UI-centric scripts, because they are hard to debug, non-compiled, usually a maintenance nightmare, almost always start to contain business logic, and duplicate some of the logic that back-end tiers have (especially validation) custom-coding for Desktop Web and Mobile Web UI's separately (although I realize that mobile web UI will likely contain fewer of data-entry screens and more reporting screens) non-.NET technology stacks I would love to: target the reporting capabilities of the system toward mobile web browsers not have to write a single line of script (javascript, jquery, etc.) utilize a good collection of controls that produces an elegant UI use .NET for everything The way I see it right now, I need to re-write this app in Silverlight, utilize a 3rd party UI framework like Telerik, and re-do the reports UI again for mobile platforms separately. However, I'm rather concerned about the shelf-life of Silverlight and the needed to deploy a different architecture to deal with mobile platform. Is there an ASP.NET/MVC/Ajax architecture/framework/library that would allow me to get at the power of .NET and without painful (imho) client-side scripting, while providing a decent user experience Thank you

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  • Entity framework generates values for NOT NULL columns which has default defined in db.

    - by Muhammad Kashif Nadeem
    Hi I have a table Customer. One of the columns in table is DateCreated. This column is NOT NULL but default values is defined for this column in db. When I add new Customer using EF4 from my code. var customer = new Customer(); customer.CustomerName = "Hello"; customer.Email = "[email protected]"; // Watch out commented out. //customer.DateCreated = DateTime.Now; context.AddToCustomers(customer); context.SaveChanges(); Above code generates following query. exec sp_executesql N'insert [dbo].[Customers]([CustomerName], [Email], [Phone], [DateCreated], [DateUpdated]) values (@0, @1, null, @2, null) select [CustomerId] from [dbo].[Customers] where @@ROWCOUNT > 0 and [CustomerId] = scope_identity() ',N'@0 varchar(100),@1 varchar(100),@2 datetime2(7) ',@0='Hello',@1='[email protected]',@2='0001-01-01 00:00:00' And throws following error The conversion of a datetime2 data type to a datetime data type resulted in an out-of-range value. The statement has been terminated. Can you please tell me how NOT NULL columns which has default values at db level should not have values generated by EF? DB: DateCreated DATETIME NOT NULL DateCreated Properties in EF: Nullable: False Getter/Setter: public Type: DateTime DefaultValue: None Thanks.

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  • Why does the entity framework need an ICollection for lazy loading?

    - by Akk
    I want to write a rich domain class such as public class Product { public IEnumerable<Photo> Photos {get; private set;} public void AddPhoto(){...} public void RemovePhoto(){...} } But the entity framework (V4 code first approach) requires an ICollection type for lazy loading! The above code no longer works as designed since clients can bypass the AddPhoto / RemovePhoto method and directly call the add method on ICollection. This is not good. public class Product { public ICollection<Photo> Photos {get; private set;} //Bad public void AddPhoto(){...} public void RemovePhoto(){...} } It's getting really frustrating trying to implement DDD with the EF4. Why did they choose the ICollection for lazy loading? How can i overcome this? Does NHibernate offer me a better DDD experience?

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  • Are ternary operators not valid for linq-to-sql queries?

    - by KallDrexx
    I am trying to display a nullable date time in my JSON response. In my MVC Controller I am running the following query: var requests = (from r in _context.TestRequests where r.scheduled_time == null && r.TestRequestRuns.Count > 0 select new { id = r.id, name = r.name, start = DateAndTimeDisplayString(r.TestRequestRuns.First().start_dt), end = r.TestRequestRuns.First().end_dt.HasValue ? DateAndTimeDisplayString(r.TestRequestRuns.First().end_dt.Value) : string.Empty }); When I run requests.ToArray() I get the following exception: Could not translate expression ' Table(TestRequest) .Where(r => ((r.scheduled_time == null) AndAlso (r.TestRequestRuns.Count > 0))) .Select(r => new <>f__AnonymousType18`4(id = r.id, name = r.name, start = value(QAWebTools.Controllers.TestRequestsController). DateAndTimeDisplayString(r.TestRequestRuns.First().start_dt), end = IIF(r.TestRequestRuns.First().end_dt.HasValue, value(QAWebTools.Controllers.TestRequestsController). DateAndTimeDisplayString(r.TestRequestRuns.First().end_dt.Value), Invoke(value(System.Func`1[System.String])))))' into SQL and could not treat it as a local expression. If I comment out the end = line, everything seems to run correctly, so it doesn't seem to be the use of my local DateAndTimeDisplayString method, so the only thing I can think of is Linq to Sql doesn't like Ternary operators? I think I've used ternary operators before, but I can't remember if I did it in this code base or another code base (that uses EF4 instead of L2S). Is this true, or am I missing some other issue?

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  • Trying to edit an entity with data from dropdowns in MVC...

    - by user598352
    Hello! I'm having trouble getting my head around sending multiple models to a view in mvc. My problem is the following. Using EF4 I have a table with attributes organised by category. Couldn't post an image :-( [Have a table called attributes (AttributeTitle, AttributeName, CategoryID) connected to a table called Category (CategoryTitle).] What I want to do is be able to edit an attribute entity and have a dropdown of categories to choose from. I tried to make a custom viewmodel public class AttributeViewModel { public AttributeViewModel() { } public Attribute Attribute { get; set; } public IQueryable<Category> AllCategories { get; set; } } But it just ended up being a mess. <div class="editor-field"> <%: Html.DropDownList("Category", new SelectList((IEnumerable)Model.AllCategories, "CategoryID", "CategoryName")) %> </div> I was getting it back to the controller... [HttpPost] public ActionResult Edit(int AttributeID, FormCollection formcollection) { var _attribute = ProfileDB.GetAttribute(AttributeID); int _selcategory = Convert.ToInt32(formcollection["Category"]); _attribute.CategoryID = (int)_selcategory; try { UpdateModel(_attribute); (<---Error here) ProfileDB.SaveChanges(); return RedirectToAction("Index"); } catch (Exception e) { return View(_attribute); } } I've debugged the code and my _attribute looks correct and _attribute.CategoryID = (int)_selcategory updates the model, but then I get the error. Somewhere here I thought that there should be a cleaner way to do this, and that if I could only send two models to the view instead of having to make a custom viewmodel. To sum it up: I want to edit my attribute and have a dropdown of all of the available categories. Any help much appreciated!

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