public void UpdateParent()
{
if (_modifiedEntries != null)
{
_dbContextScope.RefreshEntitiesInParentScope(_modifiedEntries);
}
}
public void SendWelcomeEmail(Guid userId)
{
/*
* Demo of forcing the creation of a new DbContextScope
* to ensure that changes made to the model in this service
* method are persisted even if that method happens to get
* called within the scope of a wider business transaction
* that eventually fails for any reason.
*
* This is an advanced feature that should be used as rarely
* as possible (and ideally, never).
*/
// We're going to send a welcome email to the provided user
// (if one hasn't been sent already). Once sent, we'll update
// that User entity in our DB to record that its Welcome email
// has been sent.
// Emails can't be rolled-back. Once they're sent, they're sent.
// So once the email has been sent successfully, we absolutely
// must persist this fact in our DB. Even if that method is called
// by another busines logic service method as part of a wider
// business transaction and even if that parent business transaction
// ends up failing for any reason, we still must ensure that
// we have recorded the fact that the Welcome email has been sent.
// Otherwise, we would risk spamming our users with repeated Welcome
// emails.
// Force the creation of a new DbContextScope so that the changes we make here are
// guaranteed to get persisted regardless of what happens after this method has completed.
using (IDbContextScope dbContextScope = _dbContextScopeFactory.Create(DbContextScopeOption.ForceCreateNew))
{
UserManagementDbContext dbContext = dbContextScope.DbContexts.Get <UserManagementDbContext>();
#if EF6
User user = dbContext.Users.Find(userId);
#elif EFCore
var user = dbContext.Users.SingleOrDefault(x => x.Id == userId);
#endif
if (user == null)
{
throw new ArgumentException($"Invalid userId provided: {userId}. Couldn't find a User with this ID.");
}
if (!user.WelcomeEmailSent)
{
SendEmail(user.Email);
user.WelcomeEmailSent = true;
}
dbContextScope.SaveChanges();
// When you force the creation of a new DbContextScope, you must force the parent
// scope (if any) to reload the entities you've modified here. Otherwise, the method calling
// you might not be able to see the changes you made here.
dbContextScope.RefreshEntitiesInParentScope(new List <User> {
user
});
}
}
