what's wrong with this code?

private sub test(ctl as textbox)
ctl.text="blah blah"
end sub

private sub txttest_gotfocus()
test(txttest)
end sub

in this code i want to write blah blah when the textbox
get focus, but when the control does get focus in run
time, an error message pops up saying "type mismatch"

(i tried to write "ctl as control", but it didnt work as well)