entity-framework-4.3

问题 Take this: int? item1 = null; int? item2 = null; someObjectList.Where(x => x.SomeItem1 == (item1 ?? x.SomeItem1) && x.SomeItem2 == (item2 ?? x.SomeItem2) ); Where someObjectList is not empty and SomeItem1 and SomeItem2 is null in all the objects in the list. Why is it returning nothing? EDIT: My Code: public void GetPlacementsByMaterial(long clientMaterialID) { ClientMaterial clientMaterial = ((ApplicationEntityModel)NavigationItem.ObjectContext).ClientMaterial.FirstOrDefault(x => x

问题 Take this: int? item1 = null; int? item2 = null; someObjectList.Where(x => x.SomeItem1 == (item1 ?? x.SomeItem1) && x.SomeItem2 == (item2 ?? x.SomeItem2) ); Where someObjectList is not empty and SomeItem1 and SomeItem2 is null in all the objects in the list. Why is it returning nothing? EDIT: My Code: public void GetPlacementsByMaterial(long clientMaterialID) { ClientMaterial clientMaterial = ((ApplicationEntityModel)NavigationItem.ObjectContext).ClientMaterial.FirstOrDefault(x => x

问题 I have set up a 1-to-1 relationship using EF code first following the method prescribed here: Unidirectional One-To-One relationship in Entity Framework My mapping looks like this ... protected override void OnModelCreating(DbModelBuilder modelBuilder) { modelBuilder.Entity<Asset>() .HasRequired(i => i.NewsItem) .WithOptional(e => e.Asset) .Map(m => m.MapKey("NewsItemId")); } But when I get this exception ... A relationship from the 'Asset_NewsItem' AssociationSet is in the 'Deleted' state.

问题 Is there a way to decorate your POCO classes to automatically eager-load child entities without having to use Include() every time you load them? Say I have a Class Car, with Complex-typed Properties for Wheels, Doors, Engine, Bumper, Windows, Exhaust, etc. And in my app I need to load my car from my DbContext 20 different places with different queries, etc. I don't want to have to specify that I want to include all of the properties every time I want to load my car. I want to say List<Car>

问题 I'm having an issue with EF Migrations, specifically with getting the "Enable-Migrations" command to work. When I execute the command in the Package Manager Console I receive the following error: System.Management.Automation.PSArgumentException: Cannot find type System.Data.Entity.Migrations.MigrationsCommands]: make sure the assembly containing this type is loaded. at System.Management.Automation.MshCommandRuntime.ThrowTerminatingError(ErrorRecord errorRecord) Cannot find type [System.Data

问题 I've recently created a new web project using entity framework 4.3. I'm using database first design. Entity Framework added this section to my web.config, which is giving some informational error messages. I've read somewhere that this code relates to code first design - do I need it - do I just remove it? <entityFramework> <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlCeConnectionFactory, EntityFramework"> <parameters> <parameter value="System.Data.SqlServerCe.4.0" />

问题 I am doing data-migration for my project. But I have one question, for example: I have Book table with following fields: ID Name Color 1 Java red 2 MVC blue 3 .Net blue I tried to change the name of field from "Color" to "BookColor" using Code First tech. But after migration the table looked like this: ID Name BookColor 1 Java null 2 MVC null 3 .Net null I lost my field values. How can I make sure that all value are transfered? I'm using Entity Framework with MVC3 EDIT This is my DBMigration

问题 Using: EF 4.3.1, Visual Studio 2010, SQL CE 4.0 My understanding is that when declaring Foreign Keys with DataAnnotation in EF, it can be done either of the following ways: Option 1- [ForeignKey("Player1Home")] public long? HPlayer1Id { get; set; } public virtual Player Player1Home { get; set; } Option 2- public long? HPlayer1Id { get; set; } [ForeignKey("HPlayer1Id")] public virtual Player Player1Home { get; set; } Problem: When the InverseProperty DataAnnotation gets used with Option 2 an

问题 I have an entity model with User and Person entities, such that each User must be associated with exactly 1 Person , and each Person can be associated zero or 1 User . User (0..1) <-------> (1) Person The association is mapped fluently. Originally I only had it declared on the Person side: private class PersonOrm : EntityTypeConfiguration<Person> { internal PersonOrm() { ToTable(typeof(Person).Name, DbSchemaName.People); // has zero or one User HasOptional(p => p.User) .WithRequired(d => d

问题 I am using Entity Framework 4 with my Asp.Net MVC3 application. My problem is that I am using Entity Framework to perform action with my database , That is working fine. For some other purpose I am also using Sql Connection to Store and Retrieve my data from database. I am getting [Keyword not supported: 'metadata'] error while connecting with my database. This is my web config <add name="VibrantEntities" connectionString="metadata=res://*/Vibrant.csdl|res://*/Vibrant.ssdl|res://*/Vibrant.msl