0

我有以下代码：

using (var db = new SourceLogContext())
{
    db.LogEntries.Attach(this);
    db.Entry(this).Collection(c => c.ChangedFiles).Load();
}

我得到以下异常：

System.InvalidOperationException occurred
  Message=Conflicting changes to the role 'LogEntry_LogSubscription_Target' of the relationship 'SourceLog.Model.LogEntry_LogSubscription' have been detected.
  Source=System.Data.Entity
  StackTrace:
       at System.Data.Objects.DataClasses.RelatedEnd.IncludeEntity(IEntityWrapper wrappedEntity, Boolean addRelationshipAsUnchanged, Boolean doAttach)
       at System.Data.Objects.DataClasses.EntityCollection`1.Include(Boolean addRelationshipAsUnchanged, Boolean doAttach)
       at System.Data.Objects.DataClasses.RelatedEnd.WalkObjectGraphToIncludeAllRelatedEntities(IEntityWrapper wrappedEntity, Boolean addRelationshipAsUnchanged, Boolean doAttach)
       at System.Data.Objects.DataClasses.RelatedEnd.AddGraphToObjectStateManager(IEntityWrapper wrappedEntity, Boolean relationshipAlreadyExists, Boolean addRelationshipAsUnchanged, Boolean doAttach)
       at System.Data.Objects.DataClasses.RelatedEnd.IncludeEntity(IEntityWrapper wrappedEntity, Boolean addRelationshipAsUnchanged, Boolean doAttach)
       at System.Data.Objects.DataClasses.EntityReference`1.Include(Boolean addRelationshipAsUnchanged, Boolean doAttach)
       at System.Data.Objects.DataClasses.RelationshipManager.AddRelatedEntitiesToObjectStateManager(Boolean doAttach)
       at System.Data.Objects.ObjectContext.AttachTo(String entitySetName, Object entity)
       at System.Data.Entity.Internal.Linq.InternalSet`1.<>c__DisplayClass2.<Attach>b__1()
       at System.Data.Entity.Internal.Linq.InternalSet`1.ActOnSet(Action action, EntityState newState, Object entity, String methodName)
       at System.Data.Entity.Internal.Linq.InternalSet`1.Attach(Object entity)
       at System.Data.Entity.DbSet`1.Attach(TEntity entity)
       at SourceLog.Model.LogEntry.LoadChangedFiles() in C:\github.com\tomhunter-gh\SourceLog\SourceLog.Model\LogEntry.cs:line 62
  InnerException: (empty)

违规行在这里：https ://github.com/tomhunter-gh/SourceLog/blob/443fb74a37db89522f85b4dfc941c52922785e7a/SourceLog.Model/LogEntry.cs#L62

LogEntry 在此处分配了 LogSubscription：https ://github.com/tomhunter-gh/SourceLog/blob/443fb74a37db89522f85b4dfc941c52922785e7a/SourceLog.Model/LogSubscription.cs#L88

看起来该分配创建了一个新的 LogSubscription 实例并对其进行分配，然后 Attach 引用了一个不同的实例（但具有相同的 Id）。为什么这会导致错误，我将如何避免它？

在 LogSubscription L88 中，我基本上是在尝试将 LogEntry 添加到 LogSubscription 的集合属性中，但没有加载整个 LogEntry 集合。这是正确的方法吗？

4

2 回答 2

0

通过不附加 LogEntry 实体来避免错误，而只是在数据库中查询 ChangedFiles 集合：

using (var db = new SourceLogContext())
{
    ChangedFiles = db.LogEntries.Where(x => x.LogEntryId == LogEntryId).Include(x => x.ChangedFiles).Single().ChangedFiles;
}
于 2012-11-05T09:16:53.543 回答
0

在另一种情况下，我实际上通过覆盖Equals()and解决了这个问题GetHashCode()：

public override bool Equals(object obj)
{
    var logEntry = obj as LogEntry;
    if (logEntry == null)
        return false;
    return LogEntryId.Equals(logEntry.LogEntryId);
}

public override int GetHashCode()
{
    return LogEntryId.GetHashCode();
}
于 2013-01-20T23:01:54.377 回答