Yeah, that's the code, but there is a good chance that the resulting Query is not what you think it is. In some scenarios, ComboBox1.SelectedItem will return something considerably different from what you are expecting. In fact, it might return a type name.

So, the first thing you need to do is put a breakpoint on this line:

COMMAND = New MySqlCommand(Query, mydbcon)

When execution stops on the breakpoint, take a look at what is in Query. If it looks right, then that's not the issue, but there's a good chance that you'll have concatenated something into that query that will really surprise you.

One other point I would make is about what you are selecting. I don't know MySQL, so you may well have that right. It wouldn't be right for the T-SQL in SQL Server, though. Wrapping something in single quotes would create a string literal in the output, with no field name. If that's the right syntax for MySQL, then that's fine. I know they're different.