asp.net populate dropdown problem

Hello,

I am having difficulty in trying to populate a dropdown, I can do this fine untill i add WHERE to the statement.

I have created a page where the user logs in and the username is then displayed in a text field called 'user' - i want the sql statement to do this:

SELECT regnumber
FROM regdetails
WHERE username = user

If i substitute the user for the actual user for eg
WHERE username = 'Peter'
then it works fine

i have tried using Dreamweaver dataset complier but can not get it to work. (also its in C#)

Hope somebody can help or advise

many thanks

Lance