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.NET Forum / .NET Framework / New Users / March 2008LINQ delete
I have a problem. I am trying to delete an object like this try { dataClasses1.myobjetcs.DeleteOnSubmit(obj); dataClasses1.SubmitChanges(); } catch { MessageBox.Show("нельзя удалить"); } And if delete fails, i can not work with my database any more, because on any dataClasses1.SubmitChanges() called, i have an error. I have tryed to refresh obj state like this dataClasses1.Refresh(System.Data.Linq.RefreshMode.OverwriteCurrentValues, obj); but it don't helps. best regards Poly > I have a problem. > I am trying to delete an object like this [quoted text clipped - 14 lines] > > but it don't helps. In my experience with other ORMs, if anything fails at the database it's best to start with a fresh context anyway.  SignatureJon Skeet - <skeet@pobox.com> http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet World class .NET training in the UK: http://iterativetraining.co.uk >> I have a problem. >> I am trying to delete an object like this [quoted text clipped - 17 lines] > In my experience with other ORMs, if anything fails at the database > it's best to start with a fresh context anyway. thnks, i thought about it. but is there only way? Signature___________ best regards Poly <snip> > > In my experience with other ORMs, if anything fails at the database > > it's best to start with a fresh context anyway. > > thnks, i thought about it. > but is there only way? I don't know, I'm afraid - I'm far from an expert on LINQ to SQL. SignatureJon Skeet - <skeet@pobox.com> http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet World class .NET training in the UK: http://iterativetraining.co.uk > <snip> > [quoted text clipped - 4 lines] > > I don't know, I'm afraid - I'm far from an expert on LINQ to SQL. I tried to create new datacontext but i cant make this way =(. I have lots of objects traked datacontext and if i reload datacontext all tracking failed. Signature___________ best regards Poly > >>> In my experience with other ORMs, if anything fails at the database > >>> it's best to start with a fresh context anyway. [quoted text clipped - 6 lines] > lots of objects traked datacontext and if i reload datacontext all > tracking failed. What's your design here? In my previous experience, I've written web services using ORMs - and the whole service call fails if any database call fails (and any existing transactions are aborted). Do you really have to keep going with your half-working data? SignatureJon Skeet - <skeet@pobox.com> http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet World class .NET training in the UK: http://iterativetraining.co.uk > Do you really have to keep going with your half-working data? If i can not delete an item i need only to show message about it and to continue working. Signature___________ best regards Poly > > Do you really have to keep going with your half-working data? > > If i can not delete an item i need only to show message about it and to > continue working. In that case, I'm afraid you need someone with more LINQ to SQL experience than me :( SignatureJon Skeet - <skeet@pobox.com> http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet World class .NET training in the UK: http://iterativetraining.co.uk > > Do you really have to keep going with your half-working data? > > If i can not delete an item i need only to show message about it and > to continue working. The problem with Linq to Sql's context is that it is an entire unit of work. This means that all entities which are 'dirty' (== changed or new), or marked for deletion will be persisted in 1 transaction when you say SubmitChanges. If one of those entities fails, you'll run into the problem that the whole transaction has to roll back. With the GetChangeSet method you get the list of entities which are dirty or otherwise involved in the transaction. I don't know if Linq to Sql throws an exception which contains the entity which was involved, but the exception might be helpful in fixing the issue. The entity which caused the transaction to fail has to be removed from the context, otherwise you'll never make it work. FB Signature------------------------------------------------------------------------ Lead developer of LLBLGen Pro, the productive O/R mapper for .NET LLBLGen Pro website: http://www.llblgen.com My .NET blog: http://weblogs.asp.net/fbouma Microsoft MVP (C#) ------------------------------------------------------------------------ Frans, > I don't know if Linq to Sql throws an exception which contains the > entity which was involved, but the exception might be helpful in fixing > the issue. When you use SubmitChanges(ConflictMode.ContinueOnConflict); then you can query all conflicts via the DataContext property "ChangeConflicts". > The entity which caused the transaction to fail has to be removed from > the context, otherwise you'll never make it work. Each member of the ChangeConflicts collection (type ObjectChangeConflict) contains lots of data why it failed and also a method "Resolve" for reloading from database and an overload which helps with rows which where deleted in the database meanwhile. Signature/\/\arkus.
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