entity-framework

问题 i´m having some troubles when it comes to modify and add child rows at the same time. I´m using the technique from the answer: stackoverflow.com/questions/5557829/.... The problem is in the following code: public void EditReport(tbl_inspection inspection) { foreach (var roll in inspection.tbl_inspection_roll) { container.tbl_inspection_roll.Attach(roll); container.ObjectStateManager.ChangeObjectState(roll, (roll.id_inspection_roll == 0) ? EntityState.Added : EntityState.Modified); } container

问题 i´m having some troubles when it comes to modify and add child rows at the same time. I´m using the technique from the answer: stackoverflow.com/questions/5557829/.... The problem is in the following code: public void EditReport(tbl_inspection inspection) { foreach (var roll in inspection.tbl_inspection_roll) { container.tbl_inspection_roll.Attach(roll); container.ObjectStateManager.ChangeObjectState(roll, (roll.id_inspection_roll == 0) ? EntityState.Added : EntityState.Modified); } container

问题 I has two classes named Contact and ContactField as following. When the ContactField is added into Contact , I hope to assign SortOrder to ContactField automatically. Do I need to inherit DbSet and customize the Add method ? How to achieve it ? public class Foo { private MyDbContext _db = new MyDbContext(); public void HelloWorld() { Contact contact = ....; //< A contact from database. ContactField field = ....; ///< A new field .... ///< assign other properties into this `field` field

问题 I am working on setting up a new project using Code First for entity framework 5 in silverlight using RIA services. I have created a test project due to some issues I have encountered and will post the code below. Namely, I get an 'Object reference not set to an instance of an object' error anytime I attempt to build the silverlight client project which should generate the client proxy classes. Just to be clear, this error is not while running or debugging the application, but when building

问题 I am working on setting up a new project using Code First for entity framework 5 in silverlight using RIA services. I have created a test project due to some issues I have encountered and will post the code below. Namely, I get an 'Object reference not set to an instance of an object' error anytime I attempt to build the silverlight client project which should generate the client proxy classes. Just to be clear, this error is not while running or debugging the application, but when building

问题 I am working on setting up a new project using Code First for entity framework 5 in silverlight using RIA services. I have created a test project due to some issues I have encountered and will post the code below. Namely, I get an 'Object reference not set to an instance of an object' error anytime I attempt to build the silverlight client project which should generate the client proxy classes. Just to be clear, this error is not while running or debugging the application, but when building

问题 Does EF 6 (code first) supports complex type collection(Value Object collections) mappings? I know that it supports Complex types, but haven't still found an example where we have a collection of complex types. For instance, suppose you have an entity called Student, which has a collection of contacts. With NH, I can simply say that Student has a collection of contacts and that contact is a component (equivalent to complex type in ef). Can this be done with EF without changing contact to an

问题 EF is generating different SQL for the for two similar statements listed below var test = dbcontext.Persons.GetAll() .Where(c => c.PersonID == 2) .Select(c => c.PersonName) .FirstOrDefault();` Generated SQL: SELECT [Limit1].[PersonName ] AS [PersonName ] FROM (SELECT TOP (1) [Extent1].[PersonName ] AS [PersonName ] FROM [dbo].[ApplicationRequest] AS [Extent1] WHERE [Extent1].[PersonID ] = @p__linq__0) AS [Limit1]',N'@p__linq__0 uniqueidentifier',@p__linq__0= "2" I am using the above

问题 EF is generating different SQL for the for two similar statements listed below var test = dbcontext.Persons.GetAll() .Where(c => c.PersonID == 2) .Select(c => c.PersonName) .FirstOrDefault();` Generated SQL: SELECT [Limit1].[PersonName ] AS [PersonName ] FROM (SELECT TOP (1) [Extent1].[PersonName ] AS [PersonName ] FROM [dbo].[ApplicationRequest] AS [Extent1] WHERE [Extent1].[PersonID ] = @p__linq__0) AS [Limit1]',N'@p__linq__0 uniqueidentifier',@p__linq__0= "2" I am using the above

问题 In Visual Studio 2010, my solution was using .NET 4.2 (Entity Framework June 2011 CTP) so I could use spatial types in Entity Framework. When I upgraded to Visual Studio 11 Beta, it wouldn't build because of conflicts between the 4.2 and 4.5 framework so I uninstalled 4.2. Now I get this error when I build: Error 209: Currently, spatial types are only supported when used in CSDL files that have the UseStrongSpatialTypes annotation with a false value on their root Schema element. Anyone know