NullReferenceException when calling InsertOnSubmit in Linq to Sql

Question

I\'m trying to insert a new object into my database using LINQ to SQL but get a NullReferenceException when I call InsertOnSubmit() in the code snippet below. I\'m passing i

Answer 1

After doing a little research, I came to the conclusion that there's no easy way to solve this problem of submitting the inherited object directly. It's possible to Map Inheritance Hierarchies but this has nothing to do with what you pretend. You just want to submit the base class and don't care if it's actually a derived class.

If you don't want to use a partial class to add additional properties or behavior to your table class, as suggested in the thread you mentioned, I would do a simple Clone method as a workaround:

    public partial class Audit
    {
        // ...
        public Audit Concrete()
        {
            if (this.GetType().Equals(typeof(Audit)))
                return this;
            else
            {
                Audit audit = new Audit();
                // clone properties
                return audit;
            }
        }
    }

//...
dataContext.Audits.InsertOnSubmit(audit.Concrete());