How to get id from entity for Auditlog in Entity Framework 6
I know it's several similar posts out there, but I cannot find any with a solution to this issue.
I want to add a (sort of) AudioLog when adding, changing or deleting entities (soft-delete) in Entity Framework 6. I've overridden the SaveChanges and because I only want to add log entries for EntityStates Added, Modified or Deleted, I fetch the list before I call SaveChanges the first time. The problem is, because I need to log what operation has been executed, I need to inspect the EntityState of the entities. But after SaveChanges is called, the EntityState is Unchanged for all entries.
public override int SaveChanges()
{
using (var scope = new TransactionScope())
{
var modifiedEntries = ChangeTracker.Entries()
.Where(e => e.State == EntityState.Added || e.State == EntityState.Deleted || e.State == EntityState.Modified)
.ToList();
int changes = base.SaveChanges();
foreach (var entry in modifiedEntries)
{
ApplyAuditLog(entry);
}
base.SaveChanges();
scope.Complete();
return changes;
}
}
private void ApplyAuditLog(DbEntityEntry entry)
{
ILog entity = entry.Entity as ILog;
if (entity != null)
{
LogOperation operation;
switch (entry.State)
{
case EntityState.Added:
operation = LogOperation.CreateEntity;
break;
case EntityState.Deleted:
operation = LogOperation.DeleteEntity;
break;
case EntityState.Modified:
operation = LogOperation.UpdateEntity;
break;
default:
throw new ArgumentOutOfRangeException();
}
AuditLog log = new AuditLog
{
Created = DateTime.Now,
Entity = entry.Entity.GetType().Name,
EntityId = entity.Id,
Operation = operation,
};
AuditLog.Add(log);
}
}
Ahhh... Off course!! The id will only be a "problem" for the entities that are newly added, so by splitting the list into two (one for modified/deleted and one for added), I create the AuditLog in two stages.
For anyone else who want to apply this kind of AuditLog, here is my working code:
public override int SaveChanges()
{
using (var scope = new TransactionScope())
{
var addedEntries = ChangeTracker.Entries().Where(e => e.State == EntityState.Added).ToList();
var modifiedEntries = ChangeTracker.Entries().Where(e => e.State == EntityState.Deleted || e.State == EntityState.Modified).ToList();
foreach (var entry in modifiedEntries)
{
ApplyAuditLog(entry);
}
int changes = base.SaveChanges();
foreach (var entry in addedEntries)
{
ApplyAuditLog(entry, LogOperation.CreateEntity);
}
base.SaveChanges();
scope.Complete();
return changes;
}
}
private void ApplyAuditLog(DbEntityEntry entry)
{
LogOperation operation;
switch (entry.State)
{
case EntityState.Added:
operation = LogOperation.CreateEntity;
break;
case EntityState.Deleted:
operation = LogOperation.DeleteEntity;
break;
case EntityState.Modified:
operation = LogOperation.UpdateEntity;
break;
default:
throw new ArgumentOutOfRangeException();
}
ApplyAuditLog(entry, operation);
}
private void ApplyAuditLog(DbEntityEntry entry, LogOperation logOperation)
{
ILog entity = entry.Entity as ILog;
if (entity != null)
{
AuditLog log = new AuditLog
{
Created = DateTime.Now,
Entity = entry.Entity.GetType().Name,
EntityId = entity.Id,
Operation = logOperation,
};
AuditLog.Add(log);
}
}
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