how to restrict usercontrol event in windows form application

hi,
i created one usercontrol FromAddress  and i placed one textbox and button in that and i am also created textbox text changed event.
FromDetails user control is calling into my  windows main form.
i am assigning value to usercontrol (FromDetails) textbox control in main form,that time textbox textchanged event also fired.
plz tell me how to restrict that textboxtextchange(Usercontrol(FromDetails) control(textbox)) event in our main form.