Try doing it in hard code and see what happens.

I did it in hard code and had no change.

I remembered that I had the "Error List" window minimized, so when I opened it, it was saying that it couldn't find the database - then I realized that somehow, in my Solution Explorer window, the path to my db (that I was no longer using!) was pointing to a 'file' that was where my db was - it was looking there all the time. So I removed the db reference from within my Soluton Explorer and was then able to compile my app successfully.

Because it was looking for a file in my Solution Explorer, none of the changes I made to the db location in code made any difference, but once that reference was removed, I was then able to debug my code as I should.