MVC Linq to SQL Update Object in database

Question

I have a table called Code in my LINQ to SQL datacontext. I also have a class called Codes in my Models folder. What I want to do is save the updated object Codes to my database table Code. Is this possible?

In my controller, I would pass the edited Object to my Model. My CodesRepository file contains this:

public Codes EditCode(Codes CodeToEdit)
        {
            private EventsDataContext _db = new EventsDataContext();
            Codes C = new Codes();
            C = CodeToEdit;

            _db.Codes.InsertOnSubmit(C); //error here, something about invalid arguments
             //InsertOnSubmit is for adding a new object, but I don't know the syntax
             // for editing an existing object.  

            _db.SubmitChanges();


        }

This is probably not the correct way of doing this so can someone point me in the right direction? Do I even need a class called Codes or do I need to somehow just use my database table? Thanks.

Solution: I decided to change from Linq to SQL to an Entity Framework and it works much better. This way, I don't have to define my Codes class since it comes straight from the database and I was able to delete the Codes class file.

Anders Abel · Accepted Answer · 2011-12-08 13:59:27Z

1

You should use DataContext.Attach when you get an object back that corresponds to en existing row in the database. For Linq-to-sql's optimistic concurrency handling to work this requires that you either have the original, unsaved object available, or that you have a TimeStamp column in the database. The latter is preferred, as it only requires one extra field to be handled (probably through a hidden field in the web form).

answered Dec 8, 2011 at 13:59

Anders Abel

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3 Comments

Craig Over a year ago

+1 for answering Linq To SQL and not Entity Framework! Cheers

MikeB55 Over a year ago

I tried this: _db.Codes.Attach(CodeToEdit); but i still get an error. I don't think I can take an instance of my object Codes and save it to my Code database table.

Anders Abel Over a year ago

There is some more info at msdn.microsoft.com/en-us/library/bb546187.aspx, which describes how to handle the attaching and optimistic concurrency.

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