我使用以下实体制作了代码优先模型
public abstract class Model
{
public Guid Id { get; set; }
}
public class Media : Model
{
public string Name { get; set; }
public IList<Tag> Tags { get; set; }
}
public class Tag : Model
{
public string Name { get; set; }
public IList<Media> Media { get; set; }
}
上下文:
public DbSet<Media> Media { get; set; }
public DbSet<Tag> Tags { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Tag>().HasMany(x => x.Media).WithMany(x => x.Tags).Map(x =>
{
x.ToTable("Tags_X_Media");
x.MapLeftKey("TagId");
x.MapRightKey("MediaId");
});
....
}
带接口的DataRepository:
public interface IDataRepository
{
T Update<T>(T model) where T : Model;
}
public class DataRepository : IDataRepository
{
public T Update<T>(T model) where T : Model
{
return PerformAction((context) =>
{
context.Set<T>().Attach(model);
context.Entry(model).State = System.Data.EntityState.Modified;
context.SaveChanges();
return model;
}
}
private T PerformAction<T>(Func<Context, T> toPerform) where T : Model
{
using (Context context = new Context())
{
context.Configuration.AutoDetectChangesEnabled = false;
context.Configuration.ValidateOnSaveEnabled = true;
context.Configuration.LazyLoadingEnabled = false;
context.Configuration.ProxyCreationEnabled = false;
return toPerform(context);
}
}
}
保存示例:
//get uses .Include(x => x.Tags)
var media = DbRepository.Get<Media>(p => p.Id == "the id", x => x.Tags);
media.Tags.Add(new Tag { Name = "A tag name" });
DbRepository.Update<Media>(media);
在上面的保存示例中,在交叉表Tags_X_Media中添加和删除实体的正确方法是什么?如果我将状态设置为更改,例如Media.Tags,则此状态应用于dbo.Tags中的tags-entity,我无法在表中添加新行。是否可以避免使用Tags_X_Media作为代码中的模型来实现此功能,或者这是添加或删除此实体的唯一方法吗?