Entity framework 条目框架4..5:查询生成器
我是入门框架的新手。我正在阅读Julia Lerman的书,我一直坚持使用查询生成器方法。我得到以下编译错误:Entity framework 条目框架4..5:查询生成器,entity-framework,entity,Entity Framework,Entity,我是入门框架的新手。我正在阅读Julia Lerman的书,我一直坚持使用查询生成器方法。我得到以下编译错误: Error 1 'System.Data.Entity.DbSet<Chapter2ConsoleApp.Contact>' does not contain a definition for 'Where' and the best extension method overload 'System.Linq.Queryable.Where<T
Error 1 'System.Data.Entity.DbSet<Chapter2ConsoleApp.Contact>' does not
contain a definition for 'Where' and the best extension method overload
'System.Linq.Queryable.Where<TSource>(System.Linq.IQueryable<TSource>,
System.Linq.Expressions.Expression<System.Func<TSource,bool>>)' has some invalid arguments
C:\EF\ProgrammingEntityFramework\Chapter2ConsoleApp\Program.cs 59 32
Chapter2ConsoleApp
具有lambda的Linq to实体工作正常。当我通过IntelliSense查看坏代码时,我可以看到有一个Where方法。最后,我在上下文中尝试了cast[(IObjectContextAdapter)]
,但之后我无法获得联系人方法
有人能帮我吗?使用下面的代码(确保导入
System.Data.Entity.Infrastructure
命名空间)
var contacts=((IObjectContextAdapter)context.ObjectContext.CreateObjectSet()
.Where(“it.FirstName=‘Robert’”)
.OrderBy(“it.LastName”);
谢谢,
金维
using (SampleEntities context = new SampleEntities())
{
var contacts = context.Contacts.Where("it.FirstName = 'Robert'").OrderBy("it.LastName");
foreach (Contact contact in contacts)
{
Console.WriteLine("{0} {1}",
contact.FirstName.Trim(),
contact.LastName);
}
}
Console.Write("Press Enter...");
Console.ReadLine();
}
var contacts = ((IObjectContextAdapter)context).ObjectContext.CreateObjectSet<Contact>()
.Where("it.FirstName = 'Robert'")
.OrderBy("it.LastName");