DataGridView binding after replacing column with comboboxcolumn

I'm in C# Express 2010 and SQL Server Express 2008, making a winforms front end for simple table editing. User picks a table from a combobox, and a datagridview is populated with that table. There's a Submit and Reload button at the bottom of the form. It's loosely based on Microsoft's example for binding a DGV to a database.

So, I have this datagridview that is populated by a data adaptor. After it's been populated, I go through the resulting table and replace any columns with foreign keys with comboboxcolumns so it's easier for the user.

This bit all works fine. The comboboxcolumn shows up, with the correct data in it etc etc. I've set the Headertext, DataProprtyName, and Name properties to match the column it has replaced.

It DOES seem to have broken my 'submit' button that does the update command. Basically, if I change the value in one of the comboboxcolumns, I get a concurrency violation. If I change a value in any other column, it silently fails (when the data is reloaded into the DGV, the updated value vanishes).

Any ideas what the problem could be here?

If you need to see code just let me know. There's rather a lot开发者_如何学Python of it as I'm a newbie and have probably done things in a horrendously messy way!

Thanks in advance.

Never mind - I figured it out - I had copy/pasted a procedure and forgotten to create a new DataAdaptor, so it was using the same one as the one used to populate the DGV, hence things went A over T...