get data in textbox from SQL server 2005

hi
im having problem in retreiving data in text box in C# web form.i have a dropdownlist and a textbox.i have successfully populated dropdownlist with data from SQL table.there are 2 tables namely employee and worker.dropdownlist is populated with employeee data and when i select an employee it shows relevant info. in text box from the worker table.this is the point where im having problem.
Kindly help me.