Entity Framework 4 Code First - Virtual properties not updating when changed to null

Question

So I have a model in my domain similar to this:

public class Product
{
    public virtual Tag Methodology { get; set; }
}

Then in an webform project I update it like so:

if (!string.IsNullOrWhiteSpace(ddlMethodology.SelectedValue))
    product.Methodology = TagRepo.GetTagById(int.Parse(ddlMethodology.SelectedValue));
else
    product.Methodology = null;

But this wasn't updating when product.Methodology was previously set to an object and I wanted to change it back to nothing. I.e. the product.Methodology = null; line didn't seem to work as expected.

When I ran it in the debugger I found that sometimes it would work and sometimes it wouldn't. After a small amount of hair pulling, I realised it was due to the proxy type that the entity framework was creating for that property at runtime and it was working when I inspected it in the debugger.

So to fix the issue, I created this hack which works well: (NOTE: now an else if)

if (!string.IsNullOrWhiteSpace(ddlMethodology.SelectedValue))
    product.Methodology = TagRepo.GetTagById(int.Parse(ddlMethodology.SelectedValue));
else if (product.Methodology != null)
    product.Methodology = null;

So I guess my questions are:

• Am I doing something wrong?
• Is there another way it can be done remembering to do a hack everytime?
• Could it be considered a bug in the entity framework code first CTP?

Cheers,
Charles

Answer 1

I'm having the same kind of problem, but my entity will not save. I've tried to attach it to the context before calling save. but it does not seem to work.