我使用 EntityFramework 4.1。
我想要实现的是,每当对 FooEntity 的实体调用 SaveChanges 方法时,我首先要更新这些实体,然后再删除。
我尝试覆盖下面的默认行为,但我无法实现我想要的:它在 Db 上更新。但不是删除。
我怎样才能做到这一点?
public override int SaveChanges()
{
var entitiesMarkedAsDelete = ChangeTracker.Entries<FooEntity>()
.Where(e => e.State==EntityState.Deleted);
foreach (var e in entitiesMarkedAsDelete)
{
e.State = EntityState.Modified;
}
base.SaveChanges(); // To enforce an UPDATE first
// Now, I try to re-mark them to DELETE
foreach (var e in entitiesMarkedAsDelete)
{
e.State = EntityState.Deleted;
}
base.SaveChanges(); // And hope that they will be deleted
// RESULT: 1st call of base.Savechanges() updates the entities
// but the 2nd call of base.Savechanges() does not make any changes on the UPDATED
// entities -and they are NOT DELETED.
}