Back color update issue

[GraemeG]

Hello,

I have a button which at the end of the form the user hits to validate all repsonses and completes the survey. If fields are missing they highlight red.

However some combo boxes auto fill other combo boxes depending on a repsonse. (They also hide these fields when filled in but that is not relevant at the minute)

The issue:


Say a user selects an option which auto fills other fields and then realises that that was a mistake and changes it.
The autofilled fields are set to (= "") So they become blank again.
However if they forget to fill in one of these fields and try to complete the survey it does not highlight RED but it is required so will not complete, therefore rendering the user confused.
However I have noticed that if you reenter one of these autofilled fields which are now blank and select something and delete it manually and then press the complete button it highlights red. Therefore leading me to believe that the (me.fieldname = "") is causing the issue - not actually making the field null!

Any help much appreciated!
Thanks

[GraemeG]

RESOLVED:
Changed the autofill code to:
Me.fieldname = Null (upon selection in the combobox)

[orange]

GraemeG, Be cautious with x = NULL

The syntax is along these lines
if IsNull(fieldname)......

See this link for an explanation of NULL Empty etc.
http://allenbrowne.com/vba-NothingEmpty.html

[GraemeG]

GraemeG, Be cautious with x = NULL

The syntax is along these lines
if IsNull(fieldname)......

See this link for an explanation of NULL Empty etc.
http://allenbrowne.com/vba-NothingEmpty.html

thanks - I know the about the If isnull and use it alot in my code.
But this is terms of:

Private Sub txtComAreaDecorationRenewYear_AfterUpdate()
If IsNull(txtComAreaDecorationRenewYear.Value) Then
    Me.[txtComAreaDecorationRenewYear] = ""
ElseIf Me.[txtComAreaDecorationRenewYear] < Format(Date, "yyyy") Then
    MsgBox "Renew Year Invalid:  < Current Year!"
    Me.txtComAreaDecorationRenewYear = Null
ElseIf CLng(Me.[txtComAreaDecorationRenewYear] > CLng(Format(Date, "yyyy") + 5)) Then
    MsgBox "Renew Year Invalid:  Exceeds Life Expectancy!"
    Me.txtComAreaDecorationRenewYear = Null
End If
Me.txtComAreaDecorationRenewYear.BackColor = vbWhite
End Sub