entity-framework

问题 I'm trying to access a two models in one view, basically i have two models User Model namespace SLMDemo0.Models { using System; using System.Collections.Generic; public partial class User { public int UID { get; set; } public string UserName { get; set; } public int PID { get; set; } public int LID { get; set; } public string SK { get; set; } public string Brand { get; set; } public string CN { get; set; } public string SN { get; set; } public string AT { get; set; } public string Ref { get;

问题 I am developing an application which will expose WCF services. I am using Entity Framework 4.1 at the DAL. The problem is when I load some entity (let say a Customer that has Order which in turn has OrderDetail). After loading it I make some changes in Customer, Order and OrderDetail objects (some new orders are added and some existing orders are removed/updated) and send the object graph to WCF service to update it as following. Customer oCustomer; using(var context = new MyContext) /

问题 Part 2 problem, which continues from here: EntityFramework Core - Update record fails with DbUpdateConcurrencyException Error: The derived type 'BinaryFile' cannot have KeyAttribute on property 'Id' since primary key can only be declared on the root type. I am trying to make inheritance for my entities as much as possible, so I remove duplication as much as possible. My inheritance structure: public interface IEntityMinimum { bool IsDeleted { get; set; } byte[] Version { get; set; } string

问题 This simple program private static void Main(string[] args) { Parallel.For(0, 1000000, InsertTestEntity); } private static void InsertTestEntity(int i) { using (var dbContext = new TestDbContext()) { dbContext.TestEntities.Add(new TestEntity { HugeString = "Baby shark," + string.Join(", ", Enumerable.Repeat("doo", 500)) }); dbContext.SaveChanges(); } } public class TestEntity { [Key] public int Id { get; set; } public string HugeString { get; set; } } public class TestDbContext : DbContext {

问题 I'm using entity framework with oracle database. I downloaded the provider from http://oracleef.codeplex.com/. Today I converted my project to work with VS2010. Is there a way (free) to work with oracle db using VS2010? Thanks! 回答1: Try express editions of some data providers. For example, http://www.devart.com/dotconnect/oracle/... 回答2: Well Visual Studio (and Windows) both require paying Microsoft, so "No, you can't do it for free". You can use Oracle XE (Express Edition) for free though.

问题 Code: public static IEnumerable<TableRowModel> GetRows() { var to_ret = db.TableRows.select(x=> new TableRowModel(){ TableRowId = x.TableRowId, Type = x.Type, Name = x.Name, CreatedAt = x.CreatedAt, ModifiedAt = x.ModifiedAt, Enums = x.Enums.Select(y => y.ToEnumModel()), }); return to_ret; } public static EnumModel ToEnumModel(this Enum x) { var to_ret = new EnumModel() { CFPId = x.CFPId, CreatedAt = x.CreatedAt, ModifiedAt = x.ModifiedAt, }; return to_ret; } I get the following error when

问题 I have a report in which the user can select different filters to apply to a dataset. At design time, I don't know what filters the user will apply, so I grab the whole dataset. For instance, if the user wants to see contacts that live in Chicago, I first grab all contacts... IList<contact> contacts = db.contacts.ToList(); then I check the form collection for filters and apply them... contacts = contacts.Where(t => t.state == form["state"]).ToList(); The issue is that getting all contacts to

问题 In SQL Server, uniqueidentifier columns can be used like strings with the LIKE comparison: SELECT * FROM dbo.Table WHERE GuidColumn LIKE '4c38e01e%' How can I use this feature in Entity Framework? I want something like this context.Table.Where(x => x.StringColumn.Contains("some string")) but for a Guid column instead for string columns: context.Table.Where(x => x.GuidColumn ???? "4c38e01e") 回答1: As far as I know there is no way to convert Guid to string on the fly in EntityFramework. I'm

问题 This is my first WinForm application using the Entity Framework and I have to be able to update the connection string for the entity model I created on the fly and in my app.config file I have the following connectionString: <add name="NCIPEntities" connectionString="metadata=res://*/NCIPModel.csdl|res://*/NCIPModel.ssdl|res://*/NCIPModel.msl;provider=System.Data.SQLite;provider connection string='data source="C:\Test\NCIP\NCIP.db3";pooling=True'" providerName="System.Data.EntityClient" />

问题 I have three classes Event, Dog, Result Each dog can participate in many events and for each event he will get a score related to this specifik event. Thus must mean that my result-class must contain 2 foreign keys. 1 that specifies the event and 1 that specifies the dog. I am very confused about how to set this up. I´ve been getting som help with this earlier and I hope someonen can help me again: Here are my classes now: public class Dog { public int DogId { get; set; } public string Name {