Error - you tried to assign a null value to a variable that is not a variant data type

When I want to enter data into the main form I get the error: you tried to assign a null value to a variable that is not a variant data type, when I click out of it everything works fine.

What is causing that error?
How can I fix it?

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Eric ShermanAccountant/DeveloperCommented:
I have your main form open ... Please post the steps to reproduce your error.


Eric ShermanAccountant/DeveloperCommented:
Your sub form is linked to the main form using the Contact ID field.  When you create a new record you must populate the Contact ID field first.

Coaster_brook_troutAuthor Commented:
Thanks etsherman, my Contact ID field is an autonumber. How do I get it and set it before a new record is created?
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Eric ShermanAccountant/DeveloperCommented:
<<<<<hanks etsherman, my Contact ID field is an autonumber. How do I get it and set it before a new record is created?>>>>>

Ok, looks like you have your main form and sub forms not properly structured.  Your main form should be the Contact information form that establishes the record.  Then link that main from to the sub forms such as Children, Interest, etc.

See picture below.


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It doesn't even need to be that complex...

From what I can tell the main purpose of the main form is to located a contact record and to display it in the subform.

That structure is fine, but there is no need for the link between the master and child forms, or for the main form to be bound to a table.

You can make the main form unbound, remove the master/child links and use the combo boxes to search for the subform record, simplifying the after update code like this (you'll have to use your own form/field/control names, etc):

Dim rs as Dao.recordset
Set rs = Me.MySubformName.Form.Recordset Clone
rs.FindFirst "Field1 LIKE '" & NZ(me.combo1, "*")  & "' AND Field2 LIKE '" & NZ(me.combo2, "*") &"'"
if rs.NoMatch = False Then
    Me.MySubformName.Form.Bookmark = rs.BookMark  '<---- moves the subform to the selected record
   msgbox "Record Not Found"
End If

Open in new window

And also move your navigation controls to the subform, so that they control the records in the subform directly rather than indirectly through the master child links (which is the source of your error message).
Eric ShermanAccountant/DeveloperCommented:
My solution was geared at answering the question that was asked as opposed to redeveloping what was already done.  If he makes the main form the Contact form to establish the Contact ID record given what he already has ... that seems a lot LESS complex compared to the last post!!!

Coaster_brook_troutAuthor Commented:
Both of you are incredibly thorough and easy to understand, thank you, excellent responses!
Glad to help out!

>>  If he makes the main...

ET,  I think 'she' in this case :-)
Eric ShermanAccountant/DeveloperCommented:
OOPs ... Sorry Coaster brook trout for referring to you as he instead she.  Thanks for the points.

Thanks mbizup for reminding me!!!

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