comboBox_SelectedIndexChanged

Question

hey...
i'm working on windows form, and on that form i have a comboBox that attached to a dataBase, and several empty
textBoxes that dosen't attached to anything...
now what i want is this:
when i choose a value from the comboBox then the empty textBoxes will fill with data from the dataBase...
for example, if the comboBox attached to a "person" table to the "ID" column, then when i choose an ID number from the comboBox then the empty textBoxes will fill with that same person data, like age,birthDate,height exc...

i know that i'm suppose to use the function "SelectedIndexChanged", but how?
if someone can help me or even post a similer example it will help alot
thanks!