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  • The specified type member 'EntityKey' is not supported in LINQ to Entities

    - by user300992
    I have 2 Entities "UserProfile" and "Agent", they are 1-many relationship. I want to do a query to get a list of Agents by giving the userProfileEntityKey. When I run it, I got this "The specified type member 'EntityKey' is not supported in LINQ to Entities" error. public IQueryable<Agent> GetAgentListByUserProfile(EntityKey userProfileEntityKey) { ObjectQuery<Agent> agentObjects = this.DataContext.AgentSet; IQueryable<Agent> resultQuery = (from p in agentObjects where p.UserProfile.EntityKey == userProfileEntityKey select p); return resultQuery; } So, what is the correct way to do this? Do I use p.UserProfile.UserId = UserId ? If that's the case, it's not conceptual anymore. Or should I write object query instead of LINQ query?

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  • Foreign key onto weak entity set in MS SQL Server 2008?

    - by Nic Waller
    I'm using Microsoft SQL Server 2008 Management Studio to create a relational schema by following an Entity-Relationship diagram. (included below; unrelated details removed) Until now, primary and foreign keys have been working as expected. But when I try to create a foreign key from the entity relationship takes onto the weak entity set section, I get an error. Section is identified by a composite primary key in the context of course, which has course_id as a primary key. Therefore, the primary key of section is a 4-way composite key. The entity relationship takes needs to refer to section, so it includes all 4 primary attributes from section in it's own primary key. When trying to establish a foreign key relationship from takes to section, Studio gives the following error: The columns in table 'section' do not match an existing primary key or UNIQUE constraint. Am I doing something wrong, or is this an unsupported configuration? I can provide more details or the SQL schema if necessary.

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  • EF4 CTP5 - Map foreign key without object references?

    - by anon
    I feel like this should have a simple answer, but I can't find it. I have 2 POCOs: public class Category { public int Id { get; set; } public string Name { get; set; } } public class Product { public int Id { get; set; } public int CategoryId { get; set; } } Notice that there are no object references on either POCO. With Code-First, how do I make EF4 CTP5 define a relationship between the two database tables? (I know this is an unusual scenario, but I am exploring what's possible and what's not with Code-First)

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  • Relationships in a Chen ERD

    - by Nibroc A Rehpotsirhc
    I am working on a Chen ERD to model our organizations merchandise. Our central entity is a Style. We have supplemental entities of Color and Season. I am defining our assortment as the relationship between these three entities, and this relationship itself will have attributes and is defined by the three entities which participate in the mandatory relationship. The rules are; Many Styles can be offered in a Season, and a Style can be offered in many Seasons. Within a Season, a Style can be offered in Many Colors. I then have 2 other entities, one of which I believe is a weak entity, Climate, and the other may be weak, but I am not sure, this being Transaction Channel. I am thinking of these as relationships off of a relationship? Meaning, for a given Style/Color combination offered in a Season, it can be available through 1 or more Transaction Channels. Additionally, within a season, a given Style/Color combination can be intended for 1 or more Climates. Is it valid to have relationships off of relationships? Or does this requirement dictate that I should think of this Style/Color/Season relationship as an entity itself, and define the relationships to Climate and Transaction Channel off of this entity?

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  • Can I remove the systems from a component entity system?

    - by nathan
    After reading a lot about entity/component based engines. I feel like there is no real definition for this kind of engine. Reading this thread: Implementing features in an Entity System and the linked article made me think a lot. I did not feel that comfortable using System concept so I'll write something else, inspired by this pattern. I'd like to know if you think it's a good way to organize game code and what improvements can be made. Regarding a more strict implementation of entity/component based engine, is my solution viable? Do I risk getting stuck at any point due to the lack of flexibility of this implementation (or anything else)? My engine, as for entity/component patterns has entities and components, no systems since the game logic is handled by components. Also, I think the main difference is the fact that my engine will use inherence and OOP concepts in general, I mean, I don't try to minimize them. Entity: an entity is an abstract class. It holds his position, width and height, scale and a list of linked components. The current implementation can be found here (java). Every frame, the entity will be updated (i.e all the components linked to this entity will be updated), and rendered, if a render component is specified. Component: like for entity, a component is an abstract class that must be extended to create new components. The behavior of an entity is created through his components collection. The component implementation can be found here. Components are updated when the owning entity is updated or for only one specific component (render component), rendered. Here is an example of a logic component (i.e not a renderable component, a component that's updated each frame) in charge of listening for keyboard events and a render component in charge of display a plain sprite (i.e not animated).

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  • Argument exception after trying to use TryGetObjectByKey

    - by Rickjaah
    Hi, I'm trying to retrieve an object from my database using entity (framework 4) When I use the following code it gives an ArgumentException: An item with the same key has already been added. if (databaseContext.TryGetObjectByKey(entityKey, out result)) { return (result != null && result is TEntityObject) ? result as TEntityObject : null; } else { return null; } When I check the objectContext, I see the entities, but only if I enumerate the specific list of entities manually using VS2010, it works. What am I missing? Do I have to do something else before i can get the item from the database? I have lazy loading set to true. I searched google, but could not find any results, the same for the msdn library

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  • Need help understanding Generics, How To Abstract Types Question.

    - by kmacmahon
    I could use some really good links that explain Generics and how to use them. But I also have a very specific question, relater to working on a current project. Given this class constructor: public class SecuredDomainViewModel<TDomainContext, TEntity> : DomainViewModel<TDomainContext, TEntity> where TDomainContext : DomainContext, new() where TEntity : Entity, new() public SecuredDomainViewModel(TDomainContext domainContext, ProtectedItem protectedItem) : base(domainContext) { this.protectedItem = protectedItem; } And its creation this way: DomainViewModel d; d = new SecuredDomainViewModel<MyContext, MyEntityType>(this.context, selectedProtectedItem); Assuming I have 20 different EntityTypes within MyContext, is there any easier way to call the constructor without a large switch statement? Also, since d is DomainViewModel and I later need to access methods from SecuredDomainViewModel, it seems I need to do this: if (((SecuredDomainViewModel<MyContext, MyEntityType>)d).CanEditEntity) But again "MyEntityType" could actually be one of 20 diffent types. Is there anyway to write these types of statements where MyEntityType is returned from some sort of Reflection?

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  • Need help understanding Generics, How To Abstract Types Question.

    - by kmacmahon
    I could use some really good links that explain Generics and how to use them. But I also have a very specific question, relater to working on a current project. Given this class constructor: public class SecuredDomainViewModel<TDomainContext, TEntity> : DomainViewModel<TDomainContext, TEntity> where TDomainContext : DomainContext, new() where TEntity : Entity, new() And its creation this way: DomainViewModel d; d = new SecuredDomainViewModel<MyContext, MyEntityType>(this.context, selectedProtectedItem); Assuming I have 20 EntityTypes within MyContext, is there any easier way to call the constructor without a large switch statement? Also, since d is DomainViewModel and I want to access methods for SecuredDomainViewModel, it seems I need to do this: if (((SecuredDomainViewModel<MyContext, MyEntityType>)d).IsBusy) But again "MyEntityType" could actually be one of 20 types. Is there anyway to write these types of statements where MyEntityType is returned from some sort of Reflection?

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  • Instantiating a context in LINQ to Entities

    - by Jagd
    I've seen two different manners that programmers approach when creating an entity context in their code. The first is like such, and you can find it all over the MSDN code examples: public void DoSomething() { using TaxableEducationEntities context = new TaxableEducationEntities()) { // business logic and whatever else } } The second is to create the context as a private attribute in some class that encapsulates your business logic. So you would have something like: public class Education_LINQ { private TaxableEducationEntities context = new TaxableEducationEntities(); public void DoSomething() { var result = from a in context.luAction select a; // business logic and whatever else } } Which way is more efficient? Assume that you have two methods, one called DoSomething1() and another called DoSomething2(), and both methods incorporate the using statement to open the context and do whatever with it. Were you to call one method after the other, would there be any superfluous overhead going on, since essentially both methods create the context and then clean it up when they're done? As opposed to having just one private attribute that is created when a class object is instantiated, and then in turn cleaned up when the object goes out of scope?

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  • Is there an ORM with APIs to be used programatically?

    - by Kabeer
    Hello. Neither did not get any response for my previous question, nor enough views :) So here I am now framing my query afresh. Is there any ORM that offers APIs to be used programatically? In my situation, a user will be helped through a wizard to define some entities. Thereafter those entites will be created in a database in form of tables (there will of course be some improvization). I need an ORM that offers APIs for modeling and creating entities during application runtime and not just during design time. Mine is a .Net application, therefore I was looking at Entity Framework. However, to me it looked tied to Visual Studio (I may be wrong also as I am new to it). Any recommendations? Or alternative point of view?

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  • A generic Find method to search by Guid type for class implementing IDbSet interface

    - by imak
    I am implementing a FakeDataSet class by implementing IDbSet interface. As part of implementing this interface, I have to implement Find method. All my entity classes has an Guid type Id column. I am trying to implement Find method for this FakeDbSet class but having hard time to write it in a generic way. Below is my attempts for writing this method but since it does not know about Id been Guid type, I am getting compilation error on m.Id call. Any ideas on how this could be accomplished? public class FakeDataSet<T> : IDbSet<T> where T: class, new() { // Other methods for implementing IDbSet interface public T Find(params object[] keyValues) { var keyValue = (Guid)keyValues.FirstOrDefault(); return this.SingleOrDefault(m => m.Id == keyValue); // How can I write this } }

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  • Entity Framework 4.3.1 Code based Migrations and Connector/Net 6.6

    - by GABMARTINEZ
     Code-based migrations is a new feature as part of the Connector/Net support for Entity Framework 4.3.1. In this tutorial we'll see how we can use it so we can keep track of the changes done to our database creating a new application using the code first approach. If you don't have a clear idea about how code first works we highly recommend you to check this subject before going further with this tutorial. Creating our Model and Database with Code First  From VS 2010  1. Create a new console application 2.  Add the latest Entity Framework official package using Package Manager Console (Tools Menu, then Library Package Manager -> Package Manager Console). In the Package Manager Console we have to type  Install-Package EntityFramework This will add the latest version of this library.  We will also need to make some changes to your config file. A <configSections> was added which contains the version you have from EntityFramework.  An <entityFramework> section was also added where you can set up some initialization. This section is optional and by default is generated to use SQL Express. Since we don't need it for now (we'll see more about it below) let's leave this section empty as shown below. 3. Create a new Model with a simple entity. 4. Enable Migrations to generate the our Configuration class. In the Package Manager Console we have to type  Enable-Migrations; This will make some changes in our application. It will create a new folder called Migrations where all the migrations representing the changes we do to our model.  It will also create a Configuration class that we'll be using to initialize our SQL Generator and some other values like if we want to enable Automatic Migrations.  You can see that it already has the name of our DbContext. You can also create you Configuration class manually. 5. Specify our Model Provider. We need to specify in our Class Configuration that we'll be using MySQLClient since this is not part of the generated code. Also please make sure you have added the MySql.Data and the MySql.Data.Entity references to your project. using MySql.Data.Entity;   // Add the MySQL.Data.Entity namespace public Configuration() { this.AutomaticMigrationsEnabled = false; SetSqlGenerator("MySql.Data.MySqlClient", new MySql.Data.Entity.MySqlMigrationSqlGenerator());    // This will add our MySQLClient as SQL Generator } 6. Add our Data Provider and set up our connection string <connectionStrings> <add name="PersonalContext" connectionString="server=localhost;User Id=root;database=Personal;" providerName="MySql.Data.MySqlClient" /> </connectionStrings> <system.data> <DbProviderFactories> <remove invariant="MySql.Data.MySqlClient" /> <add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient" description=".Net Framework Data Provider for MySQL" type="MySql.Data.MySqlClient.MySqlClientFactory, MySql.Data, Version=6.6.2.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" /> </DbProviderFactories> </system.data> * The version recommended to use of Connector/Net is 6.6.2 or earlier. At this point we can create our database and then start working with Migrations. So let's do some data access so our database get's created. You can run your application and you'll get your database Personal as specified in our config file. Add our first migration Migrations are a great resource as we can have a record for all the changes done and will generate the MySQL statements required to apply these changes to the database. Let's add a new property to our Person class public string Email { get; set; } If you try to run your application it will throw an exception saying  The model backing the 'PersonelContext' context has changed since the database was created. Consider using Code First Migrations to update the database (http://go.microsoft.com/fwlink/?LinkId=238269). So as suggested let's add our first migration for this change. In the Package Manager Console let's type Add-Migration AddEmailColumn Now we have the corresponding class which generate the necessary operations to update our database. namespace MigrationsFromScratch.Migrations { using System.Data.Entity.Migrations; public partial class AddEmailColumn : DbMigration { public override void Up(){ AddColumn("People", "Email", c => c.String(unicode: false)); } public override void Down() { DropColumn("People", "Email"); } } } In the Package Manager Console let's type Update-Database Now you can check your database to see all changes were succesfully applied. Now let's add a second change and generate our second migration public class Person   {       [Key]       public int PersonId { get; set;}       public string Name { get; set; }       public string Address {get; set;}       public string Email { get; set; }       public List<Skill> Skills { get; set; }   }   public class Skill   {     [Key]     public int SkillId { get; set; }     public string Description { get; set; }   }   public class PersonelContext : DbContext   {     public DbSet<Person> Persons { get; set; }     public DbSet<Skill> Skills { get; set; }   } If you would like to customize any part of this code you can do that at this step. You can see there is the up method which can update your database and the down that can revert the changes done. If you customize any code you should make sure to customize in both methods. Now let's apply this change. Update-database -verbose I added the verbose flag so you can see all the SQL generated statements to be run. Downgrading changes So far we have always upgraded to the latest migration, but there may be times when you want downgrade to a specific migration. Let's say we want to return to the status we have before our last migration. We can use the -TargetMigration option to specify the migration we'd like to return. Also you can use the -verbose flag. If you like to go  back to the Initial state you can do: Update-Database -TargetMigration:$InitialDatabase  or equivalent: Update-Database -TargetMigration:0  Migrations doesn't allow by default a migration that would ocurr in a data loss. One case when you can got this message is for example in a DropColumn operation. You can override this configuration by setting AutomaticMigrationDataLossAllowed to true in the configuration class. Also you can set your Database Initializer in case you want that these Migrations can be applied automatically and you don't have to go all the way through creating a migration and updating later the changes. Let's see how. Database Initialization by Code We can specify an initialization strategy by using Database.SetInitializer (http://msdn.microsoft.com/en-us/library/gg679461(v=vs.103)). One of the strategies that I found very useful when you are at a development stage (I mean not for production) is the MigrateDatabaseToLatestVersion. This strategy will make all the necessary migrations each time there is a change in our model that needs a database replication, this also implies that we have to enable AutomaticMigrationsEnabled flag in our Configuration class. public Configuration()         {             AutomaticMigrationsEnabled = true;             AutomaticMigrationDataLossAllowed = true;             SetSqlGenerator("MySql.Data.MySqlClient", new MySql.Data.Entity.MySqlMigrationSqlGenerator());    // This will add our MySQLClient as SQL Generator          } In the new EntityFramework section of your Config file we can set this at a context level basis.  The syntax is as follows: <contexts> <context type="Custom DbContext name, Assembly name"> <databaseInitializer type="System.Data.Entity.MigrateDatabaseToLatestVersion`2[[ Custom DbContext name, Assembly name],  [Configuration class name, Assembly name]],  EntityFramework" /> </context> </contexts> In our example this would be: The syntax is kind of odd but very convenient. This way all changes will always be applied when we do any data access in our application. There are a lot of new things to explore in EF 4.3.1 and Migrations so we'll continue writing some more posts about it. Please let us know if you have any questions or comments, also please check our forums here where we keep answering questions in general for the community.  Hope you found this information useful. Happy MySQL/.Net Coding! 

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  • EF 4.0 Code only assocation from abstract to derived

    - by Jeroen
    Using EF 4.0 Code only i want to make an assocation between an abstract and normal class. I have class 'Item', 'ContentBase' and 'Test'. 'ContentBase' is abstract and 'Test' derives from it. 'ContentBase' has a property 'Item' that links to an instance of 'Item'. So that 'Test.Item' or any class that derives from 'ContentBase' has an 'Item' navigation property. In my DB every record for Test has a matching record for Item. public class Item { public int Id { get; set;} } public abstract class ContentBase { public int ContentId { get; set;} public int Id { get; set;} public Item Item { get; set;} } public class Test : ContentBase { public string Name { get; set;} } now some init code public void SomeInitFunction() { var itemConfig = new EntityConfiguration<Item>(); itemConfig.HasKey(p => p.Id); itemConfig.Property(p => p.Id).IsIdentity(); this.ContextBuilder.Configurations.Add(itemConfig); var testConfig = new EntityConfiguration<Test>(); testConfig.HasKey(p => p.ContentId); testConfig.Property(p => p.ContentId).IsIdentity(); // the problem testConfig.Relationship(p => p.Item).HasConstraint((p, q) => p.Id == q.Id); this.ContextBuilder.Configurations.Add(testConfig); } This gives an error: A key is registered for the derived type 'Test'. Keys must be registered for the root type 'ContentBase'. anyway i try i get an error. What am i a doing wrong?

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  • Relationship between Repository and Unit of Work

    - by NullOrEmpty
    I am going to implement a repository, and I would like to use the UOW pattern since the consumer of the repository could do several operations, and I want to commit them at once. After read several articles about the matter, I still don't get how to relate this two elements, depending on the article it is being done in a way u other. Sometimes the UOW is something internal to the repository: public class Repository { UnitOfWork _uow; public Repository() { _uow = IoC.Get<UnitOfWork>(); } public void Save(Entity e) { _uow.Track(e); } public void SubmittChanges() { SaveInStorage(_uow.GetChanges()); } } And sometimes it is external: public class Repository { public void Save(Entity e, UnitOfWork uow) { uow.Track(e); } public void SubmittChanges(UnitOfWork uow) { SaveInStorage(uow.GetChanges()); } } Other times, is the UOW whom references the Repository public class UnitOfWork { Repository _repository; public UnitOfWork(Repository repository) { _repository = repository; } public void Save(Entity e) { this.Track(e); } public void SubmittChanges() { _repository.Save(this.GetChanges()); } } How are these two elements related? UOW tracks the elements that needs be changed, and repository contains the logic to persist those changes, but... who call who? Does the last make more sense? Also, who manages the connection? If several operations have to be done in the repository, I think using the same connection and even transaction is more sound, so maybe put the connection object inside the UOW and this one inside the repository makes sense as well. Cheers

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  • Problem with Entity Framework : "The underlying provider failed on Open"

    - by pokrate
    Hi, When I try to insert a record, I get this error : The underlying provider failed on Open. This error occurs only with IIS and not with VWD 2008's webserver. In the EventViewer I get this Application Error : Failed to generate a user instance of SQL Server due to a failure in starting the process for the user instance. The connection will be closed. [CLIENT: ] <add name="ASPNETDBEntities" connectionString="metadata=res://*/Models.FriendList.csdl|res://*/Models.FriendList.ssdl|res://*/Models.FriendList.msl;provider=System.Data.SqlClient;provider connection string=&quot;Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\ASPNETDB.MDF;Integrated Security=True;Connect Timeout=30;User Instance=True;MultipleActiveResultSets=True&quot;" providerName="System.Data.EntityClient" /> I am using aspnetdb.mdf file, and not any external database. I have searched enough for this, but no use. Everything works fine with VWD webserver

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  • SqlBulkCopy and Entity Framework

    - by KP
    My current project consists of 3 standard layers: data, business, and presentation. I would like to use data entities for all my data access needs. Part of the functionality of the app will that it will need to copy all data within a flat file into a database. The file is not so big so I can use SqlBulkCopy. I have found several articles regarding the usage of SqlBulkCopy class in .NET. However, all the articles are using DataTables to move data back and forth. Is there a way to use data entities along with SqlBulkCopy or will I have to use DataTables?

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  • How to use multiple DisplayName attribute using Entity Framework and ASP.Net Mvc 2

    - by Picflight
    Depending on where I use my Class, I want to be able to show a different DisplayName. I have the following class: [MetadataType(typeof(PortalMetaData))] [System.Web.Mvc.Bind(Exclude = "PortalId")] public partial class Portal { public Portal() { this.Created = DateTime.Now; } } public class PortalMetaData { [Required(ErrorMessage = "Portal name is required")] [StringLength(50, ErrorMessage = "Portal name must be under 50 characters")] public object PortalName { get; set; } [Required(ErrorMessage = "Description is required")] public object Description { get; set; } } I have a corresponding Table in the database Portal I use the Portal table with a PortalController for the Site Admin to update the records in the Portal Table. I want another user with a different Role (AsstAdmin) to be able to update this table as well. To facilitate that I am thinking of creating a separate partial class that somehow links back to the Portal Model. This would allow me to display limited Fields for update by the AsstAdmin and I can display a different name for the Field as well. How can I accomplish this task? If I add the following class which inherits from Portal than I get an exception: Unable to cast object of type 'Project1.Mvc.Models.Portal' to type 'Prpject1.Mvc.Models.Site'. [MetadataType(typeof(SiteMetaData))] public class Site : Portal { public Site() { } } public class SiteMetaData { [Required(DisplayName = "Site Description")] public object Description { get; set; } }

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  • IQueryable<> from stored procedure (entity framework)

    - by mmcteam
    I want to get IQueryable<> result when executing stored procedure. Here is peace of code that works fine: IQueryable<SomeEntitiy> someEntities; var globbalyFilteredSomeEntities = from se in m_Entities.SomeEntitiy where se.GlobalFilter == 1234 select se; I can use this to apply global filter, and later use result in such way result = globbalyFilteredSomeEntities .OrderByDescending(se => se.CreationDate) .Skip(500) .Take(10); What I want to do - use some stored procedures in global filter. I tried: Add stored procedure to m_Entities, but it returns IEnumerable<> and executes sp immediately: var globbalyFilteredSomeEntities = from se in m_Entities.SomeEntitiyStoredProcedure(1234); Materialize query using EFExtensions library, but it is IEnumerable<>. If I use AsQueryable() and OrderBy(), Skip(), Take() and after that ToList() to execute that query - I get exception that DataReader is open and I need to close it first(can't paste error - it is in russian). var globbalyFilteredSomeEntities = m_Entities.CreateStoreCommand("exec SomeEntitiyStoredProcedure(1234)") .Materialize<SomeEntitiy>(); //.AsQueryable() //.OrderByDescending(se => se.CreationDate) //.Skip(500) //.Take(10) //.ToList(); Also just skipping .AsQueryable() is not helpful - same exception. When I put ToList() query executes, but it is too expensive to execute query without Skip(), Take().

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  • Entity Framework - Condition on one to many join (Lambda)

    - by nirpi
    Hi, I have 2 entities: Customer & Account, where a customer can have multiple accounts. On the account, I have a "PlatformTypeId" field, which I need to condition on (multiple values), among other criterions. I'm using Lambda expressions, to build the query. Here's a snippet: var customerQuery = (from c in context.CustomerSet.Include("Accounts") select c); if (criterions.UserTypes != null && criterions.UserTypes.Count() > 0) { List<short> searchCriterionsUserTypes = criterions.UserTypes.Select(i => (short)i).ToList(); customerQuery = customerQuery.Where(CommonDataObjects.LinqTools.BuildContainsExpression<Customer, short>(c => c.UserTypeId, searchCriterionsUserTypes)); } // Other criterions, including the problematic platforms condition (below) var customers = customerQuery.ToList(); I can't figure out how to build the accounts' platforms condition: if (criterions.Platforms != null && criterions.Platforms.Count() > 0) { List<short> searchCriterionsPlatforms = criterions.Platforms.Select(i => (short)i).ToList(); customerQuery = customerQuery.Where(c => c.Accounts.Where(LinqTools.BuildContainsExpression<Account, short>(a => a.PlatformTypeId, searchCriterionsPlatforms))); } (The BuildContainsExpression is a method we use to build the expression for the multi-select) I'm getting a compilation error: The type arguments for method 'System.Linq.Enumerable.Where(System.Collections.Generic.IEnumerable, System.Func)' cannot be inferred from the usage. Try specifying the type arguments explicitly. Any idea how to fix this? Thanks, Nir.

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  • Random sort list with LINQ and Entity Framework in vb.net

    - by Sander Versluys
    I've seen many examples in LINQ but i'm not able to reproduce the same result in vb.net. I have following code: Dim context As New MyModel.Entities() Dim rnd As New System.Random() Dim gardens As List(Of Tuin) = (From t In context.Gardens Where _ t.Approved = True And _ Not t.Famous = True _ Order By rnd.Next() _ Select t).ToList() But i receive an error when binding this list to a control. LINQ to Entities does not recognize the method 'Int32 Next()' method, and this method cannot be translated into a store expression. Any suggestion on how to get this to work?

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  • Entity Framework: How to bind related products

    - by Waheed
    I am using the following Linq query from p in Product.Include("ProductDetails.Colors") where p.ProductID.Equals(18) select p; And then using the result of this query to bind the GridView. The productDetails are bind to the grid fine, but the Colors are not bind. To bind colors i am using <%# Eval("Colors.CategoryName") %. Error is " Field or property with the name 'Colors.CategoryName' was not found on the selected data source." But in a loop i am getting this fine. foreach (ProductDetails proDet in pd.ProductDetails) { string bar = proDet.BarCode; string color = proDet.Colors.CategoryName; }

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  • Entity Framework - ContextBuilder namespace

    - by Matt
    I apologize if this seems like an excessively dumb question. I am trying to use the ContextBuilderClass to generate my Context. I am unable to find the proper assembly and namespace to use it though. Just for reference I am on a full install of VS 2010 Pro.

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  • How to clone a Model using Entity Framework and ASP.Net Mvc 2

    - by Picflight
    I have the following class: [MetadataType(typeof(PortalMetaData))] [System.Web.Mvc.Bind(Exclude = "PortalId")] public partial class Portal { public Portal() { this.Created = DateTime.Now; } } public class PortalMetaData { [Required(ErrorMessage = "Portal name is required")] [StringLength(50, ErrorMessage = "Portal name must be under 50 characters")] public object PortalName { get; set; } [Required(ErrorMessage = "Description is required")] public object Description { get; set; } } I have a corresponding Table in the database Portal I use the Portal table with a PortalController for the Site Admin to update the records in the Portal Table. I want another user with a different Role (AsstAdmin) to be able to update this table as well. To facilitate that I am thinking of creating a separate partial class that somehow links back to the Portal Model. This would allow me to display limited Fields for update by the AsstAdmin and I can display a different name for the Field as well. How can I accomplish this task? If I add the following class which inherits from Portal than I get an exception: Unable to cast object of type 'Project1.Mvc.Models.Portal' to type 'Prpject1.Mvc.Models.Site'. [MetadataType(typeof(SiteMetaData))] public class Site : Portal { public Site() { } } public class SiteMetaData { [Required(DisplayName = "Site Description")] public object Description { get; set; } }

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  • Entity Data Model & DataGridView - Creating new objects

    - by AcousticBoom
    I'm pretty new to the EDM, so bear with me. I have a windows form that has a DataGridView on it that's bound from the EDM I created. I figured out how to update my changes fine, but it's when the user creates a new row that I'm having a problem. I tried numerous ways and many google searches, but came up with nothing so far. Here's how the data is loaded: Dim boilerID As Integer = DirectCast(ddlBoiler.SelectedValue, Integer) Dim countryID As Integer = DirectCast(ddlCountry.SelectedValue, Integer) Dim ratings = From r In _Context.Rating _ Where r.Boiler.Boiler_ID = boilerID _ And r.Country.Country_ID = countryID _ Order By r.Sequence _ Select r RatingBindingSource.DataSource = ratings.ToList() Also, all I'm doing to save the information right now is the following: Private Sub btnSave_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnSave.Click _Context.SaveChanges() End Sub I want the user to be able to use the grid's "new row" feature to add new items to the database instead of having to click a button and open a new dialog. How would this be accomplished? I can include some of the methods i tried for adding new items if anyone needs to see. Thanks!

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  • Cannot rollback ransaction with Entity Framework

    - by Luca
    I have to do queries on uncommitted changes and I tried to use transactions, but I found that it do not work if there are exceptions. I made a simple example to reproduce the problem. I have a database with only one table called "Tabella" and the table has two fields: "ID" is a autogenerated integer, and "Valore" is an integer with a Unique constraint. Then I try to run this code: using (TransactionScope scope = new TransactionScope()) { Db1Container db1 = new Db1Container(); try { db1.AddToTabella(new Tabella() { Valore = 1 }); db1.SaveChanges(); } catch { } try { db1.AddToTabella(new Tabella() { Valore = 1 }); db1.SaveChanges(); //Unique constraint is violated here and an exception is thrown } catch { } try { db1.AddToTabella(new Tabella() { Valore = 2 }); db1.SaveChanges(); } catch { } //scope.Complete(); //NEVER called } //here everything should be rolled back Now if I look into the database it should contain no records because the transaction should rollback, instead I find two records!!!! One with Valore=1 and one with Valore=2. I am missing something? It looks like the second call to SaveChanges method rollback its own changes and "deletes" the transaction, then the third call to SaveChanges commits the changes of the first and the third insert (at this point it is like the transaction not exists). I also tried to use SaveChanges(false) method (even without calling AcceptAllChanges method), but with no success: I have the same behaviour. I do not want the transaction to be rolled back automatically by SaveChanges, because I want to correct the errors (for example by user interaction in the catch statement) and make a retry. Can someone help me with this? It seems like a "bug", and it is giving me a really big headache...

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