GUI help, with making tEdit change username.

How would i make the tEdit change a global variable just as the username/password and any other global variables i might want to change.

Code:

---

var
  S : String;
  Edit : TEdit;

begin
  // code
  S := Edit.Text;
end.

---

Thanks but i got it working with somethign alot simpler! :) But thanks for input.