entity-framework-4.1

问题 I am using Entity Framework 4.1 and want to take advantage of their code-only approach. In the video located at http://channel9.msdn.com/Events/TechEd/Europe/2010/DEV212 starting at 35:00 minutes in they show a tool that reverse engineers their POCOs from their existing database. I want to do this as I have an existing database. I have installed EF 4.1 and I can create POCO entities just fine but I can't seem to find the tool they used to create POCOs from the existing database. Was this tool

问题 I am new to WCF and Entity framework. I have a class library "A" which contains DatabaseEntities.edmx (Entity Framework objectContext ). This library is exposing a class "B" which contains a function FunctionB , internally using the entity objects. I have taken this library "A" reference into a WCF web service and inside the IService.cs - I have coded it like this: [OperationContract] void FunctionB_Proxy(); Without defining any DataContract I have gone into Service1.cs and implemented this

问题 I am new to WCF and Entity framework. I have a class library "A" which contains DatabaseEntities.edmx (Entity Framework objectContext ). This library is exposing a class "B" which contains a function FunctionB , internally using the entity objects. I have taken this library "A" reference into a WCF web service and inside the IService.cs - I have coded it like this: [OperationContract] void FunctionB_Proxy(); Without defining any DataContract I have gone into Service1.cs and implemented this

问题 I have a method which writes log information in Db. This method is called in a loop. On the second insert I get the InvalidOperationException: The changes to the database were committed successfully, but an error occurred while updating the object context. The ObjectContext might be in an inconsistent state. Inner exception message: AcceptChanges cannot continue because the object's key values conflict with another object in the ObjectStateManager. Make sure that the key values are unique

问题 I am having below mentioned 2 models. GeoLocation Model : public class GeoLocation { public GeoLocation() { } public int Id { get; set; } public double Latitude { get; set; } public double Longitude { get; set; } } Provider Model : public class Provider { public Provider() { Id = Guid.NewGuid(); Created = DateTime.Now; } public Guid Id { get; set; } [Required] public string Name { get; set; } public virtual GeoLocation Location { get; set; } } Repository method : public void SetLocation

问题 I'm currently using DbContext with Ef 4.1, and I'm trying to audit all changes some of my entities. I can capture the original and current values for any Properties of an entity, however I cannot figure out how to capture the association (Foreign Key) OriginalValues of a NavigationProperty. Has anyone figured this out? 回答1: You must either include foreign keys to your entities so they will be tracked as normal values or you must convert your DbContext to ObjectContext and use more powerful

问题 I need some help, I have been searching everywhere for ages to why this keeps happening. I basically have 2 tables, Company and Address. A company can have multiple addresses. My classes and tables look like the following TABLES: create table Company ( companyid int PRIMARY KEY IDENTITY not null, name varchar(100), agencyref varchar(20), website varchar(100), phoneno varchar(20), faxno varchar(20), modified datetime DEFAULT (GETDATE()) ); create table Address ( addressid int PRIMARY KEY

问题 I have a database application that references Entity Framework 4.1. In the properties window of the project both the Configuration as well as Platform selection options are disabled. I wan't to target this application only for x64 systems. Also there are some other projects in the same Solution and they have only x86 option avaliable as platform. I don't get the idea why I couldn't target x64 systems specifically. I have windows 7 64 bit running on my pc. Any clues how to target specifically

问题 Model: public class MenuItem { public Guid Id {get;set;} public virtual Guid? ParentMenuItemId {get;set;} public virtual MenuItem ParentMenuItem {get;set;} public virtual ICollection<MenuItem> ChildMenuItems {get;set;} } current mapping: HasOptional(m => m.ParentMenuItem).WithMany(p => p.ChildMenuItems).HasForeignKey(m => m.ParentMenuItemId); I tried adding the WillCascadeOnDelete(true) , but I got an error. How should I update my mapping to allow for cascading deletes? So, If I delete a

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