Auto manage and protect Created\Updated fields with Entity Framework 5 - sql-server-2008

Question

I want so every added\changed record will have a time stamp of creation\change.
But - so it will be easy to embed and easy to manage - automatically.

Answer 1

Overwrite the 'DbContext' class or embed this in the '.tt' file (Codefirst \ DBFirst)
The code assume so you have the fields 'CreatedOn'\'ModifiedOn' inside the POCO.
If you don't have them, or you have only one - the code will work fine.
Be aware! If you use a extension (as this one) so allow you to do batch updates or changes from a stored procedure - this will not work
EDIT:
I found the source of my inspiration - thanks 'Nick' here
public override int SaveChanges()
{
var context = ((IObjectContextAdapter)this).ObjectContext;
var currentTime = DateTime.Now;
var objectStateEntries = from v in context.ObjectStateManager.GetObjectStateEntries(EntityState.Added | EntityState.Modified)
where v.IsRelationship == false && v.Entity != null
select v;
foreach (var entry in objectStateEntries)
{
var createdOnProp = entry.Entity.GetType().GetProperty("CreatedOn");
if (createdOnProp != null)
{
if (entry.State == EntityState.Added)
{
if (createdOnProp != null)
{
createdOnProp.SetValue(entry.Entity, currentTime);
}
}
else
{
Entry(entry.Entity).Property("CreatedOn").IsModified = false;
}
}
var modifiedOnProp = entry.Entity.GetType().GetProperty("ModifiedOn");
if (modifiedOnProp != null)
{
modifiedOnProp.SetValue(entry.Entity, currentTime);
}
}
return base.SaveChanges();
}