How to stop subform from creating a blank line

[JeffreyDavid]

I have a form with a subform, if the form is opened and closed with no data input, it creates a blank line in the table. Over an extended period of time, that table will be mess.
How would one go about stopping a subform from creating a blank line in the table?

 

[Kodo]

this is not a normal event. What's going on in your FORM OPEN event for the sub-form.

 

[JeffreyDavid]

this is not a normal event. What's going on in your FORM OPEN event for the sub-form.

There is nothing in the FormOpen event of the subform. My subform does have 3 cascading text boxes. In the BeforeUpdate event, I have
If IsNull(Me.ProjectNo) = "" Then
Cancel = True
End If
But when I close the form with nothing done to anything, I get an error saying 'Type Mismatch' and it refers to line:
If IsNull(Me.ProjectNo) = "" Then

So I don't know...

 

[Kodo]

If IsNull(Me.ProjectNo) = "" Then


that is not valid.

you either do

IF ISNULL(ME.PROJECTNO) THEN


or

IF ME.PROJECTNO="" THEN

but not both at the same time.