我当前正在尝试实现连接3个表的接线表。我坚持从这张桌子上删除物品。
连接表由表和导航属性的键和相关实体组成。(我简化了这一点,在完整的代码中,它具有用于备份字段的实现)
[Table("SeasonHasBroadcast")]
public partial class SeasonHasBroadcastModel : BaseModel
{
[Key]
[Column(Order = 0)]
[DatabaseGenerated(DatabaseGeneratedOption.None)]
public int SeasonShow {get; set;}
[Key]
[Column(Order = 1)]
[DatabaseGenerated(DatabaseGeneratedOption.None)]
public int SeasonNumber {get; set;}
[Key]
[Column(Order = 2)]
[StringLength(45)]
public string AirtimeDay {get; set;}
[Key]
[Column(Order = 3)]
public TimeSpan AirtimeTime {get; set;}
[Key]
[Column(Order = 4)]
[StringLength(45)]
public string NetworkName {get; set;}
public virtual AirtimeModel AirtimeLink {get; set;}
public virtual NetworkModel NetworkLink {get; set;}
public virtual SeasonModel SeasonLink {get; set;}
}
连接的表具有public virtual ICollection<SeasonHasBroadcastModel> SeasonHasBroadcasts { get; set; }
。
当我在此关系中添加新实体时,我只会在此表中添加新实体。问题是,当我尝试删除实体时。
我尝试的是用SeasonViewModel.Season.SeasonHasBroadcasts.Remove(selected);
删除。这样,我将从其他连接2个表的接线表中删除。这些表只是没有单独的表,仅通过收藏来存在。其他尝试是通过导航属性,我从每个集合中删除了selected
实体。
这两个给我带来了这个错误:
属性"季节"是对象关键信息的一部分,无法修改。
当我调试并查看dbcontext时,它在节目,播放时间和网络实体上显示了此错误,但在交界处没有。
如何从桌子上删除?
编辑
public class BaseModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
[NotifyPropertyChangedInvocator]
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
}
dbContext:
modelBuilder.Entity<AirtimeModel>()
.HasMany(e => e.SeasonHasBroadcasts)
.WithRequired(e => e.AirtimeLink)
.HasForeignKey(e => new { e.AirtimeDay, e.AirtimeTime })
.WillCascadeOnDelete(false);
modelBuilder.Entity<NetworkModel>()
.HasMany(e => e.SeasonHasBroadcasts)
.WithRequired(e => e.NetworkLink)
.WillCascadeOnDelete(false);
modelBuilder.Entity<SeasonModel>()
.HasMany(e => e.SeasonHasBroadcasts)
.WithRequired(e => e.SeasonLink)
.HasForeignKey(e => new { e.SeasonShow, e.SeasonNumber })
.WillCascadeOnDelete(false);
modelBuilder.Entity<SeasonHasBroadcastModel>()
.Property(e => e.AirtimeDay)
.IsUnicode(false);
modelBuilder.Entity<SeasonHasBroadcastModel>()
.Property(e => e.NetworkName)
.IsUnicode(false);
编辑2命令用于删除广播 公共覆盖void Execute(对象参数) { var parrentViewModel =(seleseviewModel)parrentViewModel; var selected = parrentViewModel.SelectedBroadcast;
if (selected == null) return;
if (parrentViewModel.Season.SeasonHasBroadcasts.Contains(selected))
{
//selected.SeasonLink.SeasonHasBroadcasts.Remove(selected);
//selected.AirtimeLink.SeasonHasBroadcasts.Remove(selected);
//selected.NetworkLink.SeasonHasBroadcasts.Remove(selected);
parrentViewModel.BroadcastsViewModel.Service.DeleteData(selected);
//parrentViewModel.Service.Context.SeasonHasBroadcasts.Remove(selected);
//parrentViewModel.Season.SeasonHasBroadcasts.Remove(selected);
}
parrentViewModel.SelectedBroadcast = null;
}
添加广播的命令:
public override void Execute(object parameter)
{
var parrentViewModel = (SeasonViewModel)ParrentViewModel;
parrentViewModel.NewBroadcast.SeasonLink = parrentViewModel.Season;
if (!parrentViewModel.Season.SeasonHasBroadcasts.Contains(parrentViewModel.NewBroadcast))
{
parrentViewModel.Season.SeasonHasBroadcasts.Add(parrentViewModel.NewBroadcast);
}
parrentViewModel.NewBroadcast = new SeasonHasBroadcastModel();
}
服务:(这是今天的尝试,仍然无法解决,同样的错误)
public override void DeleteData(SeasonHasBroadcastModel toDelete)
{
if (toDelete.AirtimeLink != null && Context.Entry(toDelete.AirtimeLink).State == EntityState.Detached)
Context.Airtimes.Attach(toDelete.AirtimeLink);
if (toDelete.NetworkLink != null && Context.Entry(toDelete.NetworkLink).State == EntityState.Detached)
Context.Networks.Attach(toDelete.NetworkLink);
if (toDelete.SeasonLink != null && Context.Entry(toDelete.SeasonLink).State == EntityState.Detached)
Context.Seasons.Attach(toDelete.SeasonLink);
base.DeleteData(toDelete);
}
base.deletedata:
public virtual void DeleteData(TModel toDelete)
{
_context.Set<TModel>().Remove(toDelete);
}
因此,在与我的大学的教授咨询后,我们可能会在SQL Server上存储"最简单"的解决方案。它不是最好的支出,而是它的工作。仍然想知道,如何在没有存储过程的情况下执行此操作。