>In my app when the user clicks a contact name I get a reader of the contact data and use it to load the data into the UI. If I click around on multiple contacts very fast I get
>
>"There is already an open DataReader associated with this Command which must be closed first." in my app.
>
>I have DataReader.Close() in all the right places, but it's possible to initiate another call to the ExecuteReader before the previous reader is closed.
>
>I tried Thread.Sleep(15), but it's still possible to click from one contact to another before the previous reader is done.
>
>Anyone?
>
>[UPDATE] - Now I'm not sure why I'm seeing this, because I'm clicking from one contact to another slowely and it still errors.

What version of SQL? Have you tried adding "MultipleActiveResultSets=True" to your connection string? If you are using SQL 2005 and ADO.Net 2 it should work. Otherwise, you have to ensure that you always close the connection before initiating a new one or create a separate connection for each one. It's difficult to determine without seeing code, but you could also try enclosing your DBDataReader object in a using()...(it does an implicit dispose) in some cases that won't work though so you may need the MultipleActiveResultSets set to True.

(Sorry for the typos - edited to fix most of them)