>In my application, I am using a data adapter, and I am filling it in code with dataadaptor.fill without using a connection.open and a connection.close. I assume the adapter does that myself. My question is whether or not this is a good practice or not. Does the connection always close?

Yes, this is a good practice. A .Fill() opens the connection if it's not already open and closes it only if it wasn't previously open. So, if you're going to filling more than one table you should open the connection first manually and then close it after the last .Fill(), but if you're only filling one DataSet, then don't bother with the open and close.

~~Bonnie