LINQ DataContext.SubmitChanges() in C# Reporting "Object reference not set to an instance of an object."

Question

Hi. I think a lot of people have had this issue but I'm not able to fix it or understand why I'm having it. I've been tearing hair out for a couple of hours now.

I'm getting the error, "Object reference not set to an instance of an object." on my datacontext.SubmitChanges() on the SECOND time this method runs (I'm looping through a set of ObjectName strings):

    private Object CreateObject(string ObjectName, SystemClassEnum SystemClass)
    {
        Object result = new Object();
        result.Name = ObjectName;
        result.SystemClassID = (int)SystemClass;
        _dataContext.Objects.InsertOnSubmit(result);
        _dataContext.SubmitChanges();
        return result;
    }

I thought it was because the result.Name value can be null but I don't think that anymore.

It seems like somehow the dataContext is getting closed? but in Debug Mode I check the status of the connection and it's "Open" after the error occurs.

I'm using the repository pattern and ASP.NET MVC.

The result object (new Object()) is an instance of a LINQ DBML auto-generated class that also has a partial class that I created with a single extension method attached. I don't see how the extension to the class could be causing the problem.

I'm out of ideas.

Any thoughts? Thanks for any help you can provide!!

Best regards,

Eric

Answer 1

Don't call one of your types Object - that is a seriously bad idea; you will regret it... pick a different name... (or System, etc).

Are you sure the error isn't actually on the line above (_dataContext.Objects. etc)? Unfortunately, you don't show any of the code relating to _dataContext (for example, could it have become null), and you don't indicate if (for example) you have added any partial methods to the data-context or entity, or have any events. I would expect the problem to be in one of those areas.