Before Update Event

Hi,

In Form of the MS Access.

How can I make the form cannot close if the field is Null when I click the close button?

frm1:
Field Name: Date, Id, Name

The 3 field names are required to input.

Before Update Event:
if (isnull(date)) then
date.setforce
end if
if (isnull(id)) then
id.setforce
end if
if (isnull(name)) then
name.setforce
end if

It works well when I go to next record (suppose I miss one field)
However, It doesn't work when I click the close button, the form is closed.
I want the form cannot close until fill out all fields. It cannot go to the missing fields.

I have a question, when I click close button, Must the form be closed even though I set up the field to be "setforce"?

Thanks.